Battery Revolution Clubhouse Recording - Battery Basics

0:00Transcript

0:00Thank you very much, Catherine. Yeah, just also a warm welcome from my side. You know, as Catherine has mentioned, we have both been very happy to run this for 28 weeks now. So it's been quite a journey, but I very much enjoyed it and very grateful also for many people to keep joining us. You know, there's a couple of familiar faces, so, you know, wonderful to have you with us. And yeah, looking forward to have you part of this discussion as well. Maybe just a quick word on kind of where this today's topic comes from. Last week, we had a session as well. The Basim was actually part of it as well. And we have been, you know, writing then and kind of thinking about, you know, maybe it would make sense actually to have a session which goes really, you know, just kind of covering some of these basics, some of these terms you always hear, you know, which come up in the sessions you might have read in any news or, you know, just you come across with.

0:49Because I think, you know, part of the session or like part of the idea of these sessions is to find educational content, you know, where people can learn, people can understand the sector better, you know, and be looking at this from many different angles. And we thought actually it would be quite nice to do like a more like a basic overview and, you know, really have a chance where all of you who are, you know, either in this field for a long time or new to the field can come up and ask any questions or also clarify anything, you know, which has been maybe, you know, you know, wasn't really perceived or maybe the misconceptions they came across in their own journey. And yeah, for today, we're very happy to have Basin with us, you know, who has a master's degree in the system from Upset University, a selective vehicle enthusiast and now is battery safety and cybersecurity architect at Volvo Cars in Sweden. But I'm sure you can tell us also much more about himself.

1:38And yeah, very excited for him to kick up, start the session and then open up the session for everyone to come on, share their questions, their thoughts, and we have a enjoyable session. So with this, Basin, I will pass it over to you. Yes, thank you. I hope you can hear me well. Please let me know because I'm kind of back in Egypt now. I'm not in Sweden. I'm on vacation. So I hope connections quite okay. How is this going? Can you hear me? Yes, we can. Connections. Yeah, thank you so much. So I try to try to summarize some basics, which according to me are needed to be able to understand more when it comes to the batteries and to a lot of our topics and discussions. I will get for sure support from Catherine and Simon and a lot of you who have a lot of experience in the field as well. But I have a question. Simon, would you like to have interruptions in the middle or questions in the end?

2:46I'm okay with both because I have kind of a presentation which I used to have as part of a course about batteries. So I can follow even if someone will stop me. What do you prefer? I mean, from our side, you know, whatever works best, but it can also be quite nice to have a bit of like, you know, like a block of a discussion if people want to just listen to that. But yeah, I've been also hoping for questions. I mean, you see when people raise their hand, you know, both works well from our side. So we can also see how it goes if you just... Perfect. Okay. Thank you so much. I will try to go... It's not a lot. And let me know, please, if I missed something. I try to collect as much as possible without making it too complicated or too scientific. I would just go fast. Who am I? My name is Bassem. I'm originally from Egypt. I have a master's degree in embedded systems from Opsala University in Sweden.

3:40And I have been working with batteries since for the last five years. Mainly working with software and auto-hardware and working on building battery packs in Northvolt, which is a company in Sweden and Volvo Group. And now I'm in Volvo Cars, also in Sweden. And I'm specialised now more into battery pack safety and security. I will start kicking now. Any questions before I start? Okay. I will start back. Thank you. I think the first one to start with is maybe quite basic part, which is oxidation and reduction. So basically, when we have a battery, or maybe let's start like this, a very important thing to differentiate is when we say a cell and we say a battery. Because most, very important to understand that cell is the smallest unit that builds the battery pack, which is the big pack that is inside the vehicle or inside the motor site or something like that. So when we speak about it, we say cell or we say pack.

4:54So that's very important. I will try to keep this terminology. So inside the cell, which is the smallest unit, we have basically chemical reactions, oxidation and reduction. And through these reactions, we have electrons passing through the wire, which is the vehicle. So you have oxidation, reduction, you have electrons passing through the wires and you have ions passing through inside the cell itself. And then we have the cell voltage, which is the potential difference between the electrodes of the cell. So it's a bit hard maybe on Clubhouse because I cannot really show you the picture, but the cell consists of electrode, which is anode, and then you have electrolyte, electrolyte, which is the medium where the ions will transfer. And then you have separator, which separates the anode from the other electrode, which is the cathode. One point here is some people mix up anode and cathode and positive and negative. Personally, I prefer to say anode and cathode, not to say positive and negative because it depends are you charging or discharging.

6:15That's something also to take care of. Anyway, the voltage of the cell is the potential difference between the anode and the cathode or the cathode and the anode. That's the potential difference between the two electrodes. And the second one is the cell capacity. So the cells are mainly measured in amp hour and this capacity mainly depends on the material that you are using and the size of the cell itself. Am I going too fast or is it a good pace? I think it's perfect. Okay, thank you. The next one is the specific power and this is something that you will hear a lot. You will hear a lot specific power, specific energy and energy density. So this is three terms that's really important to know about. So specific power is the power per kilogram. kilogram. So you will say it's how many kilowatts per kilogram. And this is a way to understand, for example, the higher the number, the more the kilowatts per kilogram, the better is the cell or the battery pack if it's a big one because if it's in kilowatts, for sure, it's a battery pack.

7:35So if it's a cell, the better the watt-hour per kilogram, the more the watt-hour per kilogram, the better the cell. When it comes to energy, we measure it in energy density or specific energy. The energy density, it is the energy per liter. The specific energy is the energy per kilogram. You will hear it from different companies. Some of them will use energy density. Some of them will use specific energy. So just understand the main difference. Energy density is energy per liter. Specific energy is energy per kilogram. Next is, ah, that's very important. It's the C rate. So, and this you will hear maybe a lot when it comes to maybe charging, when it comes to aging of the battery. So a C rate, if the C rate is 1C, this is how it's explained. So if the C rate is 1C, it means that you can charge this cell or this battery pack in one hour. So it's the rate of current that can charge the battery pack in one hour.

8:50So if I would say that 1C is 100 amps, then the, it is, then the battery will take 100 amps. if you charge by 100 amps, it will go from 0 to 100 within one hour. And the same goes for discharging. So when you say I discharged this battery in, by 1C, means that I charge it by the amount of current that will discharge it fully in one hour. I hope it's not too detailed. Next is something called OCV, which is the open circuit voltage. And the open circuit voltage is the potential difference between the terminals of the cell when it is disconnected from the circuit, when there is no current. Some people say when it's very little current, but let's, for simplicity, let's say it's the voltage of the cell when there is no current passing by the cell for some time. So you have to leave the cell to rest for some time, maybe 12, 20 minutes around. And then you measure the voltage of the cell and that is the open circuit voltage.

10:07And this open circuit voltage is used in determining a lot of things, but most importantly something called state of charge, which is in a lot of manufacturers it is what you will see as the gauge, like the fuel gauge kind of. This is what you will see instead of the fuel gauge in your car, if it's an electric car or a plug-in hybrid or hybrid, you will see the state of charge. And the state of charge is something that you cannot measure. You cannot have a device that will measure the state of charge of the cell or the battery pack. You need to estimate the state of charge. And you estimate it using a lot of things, but most importantly, the open circuit voltage, the one I mentioned about. Next is the state of health or the health of the battery. And that's very, very, very, very important to understand that there is no international defined definition what is the state of health. But there is two things that mainly are used to define the state of health.

11:12The first one is the capacity loss, how much of the capacity of the cell or the battery pack is left compared to the capacity of this same cell or battery pack when it was in the beginning of life. So if the capacity is 80% of the capacity in the beginning of life, then people can say it's 80% state of health. The other factor used for state of health is the increase in the resistance and the internal resistance of the cell. This is one other way to determine the state of health. But again, after my knowledge, a lot of my colleagues, there is not really a standardized definition, but these are the tools that are being used in the industry. Next is, yes, very important thing to note also, is that there are two types of batteries that you will hear about, something called primary batteries, something called secondary batteries. The primary batteries are batteries that you cannot recharge them. Secondary are the ones, but you can recharge them.

12:27And when it comes to EVs, we are more interested in secondary and most importantly in lithium-ion cells. Next, yes. When it comes to lithium-ion cells, mainly we have three main cell formats. We have prismatic cells, we have pouch cells, and we have cylindrical cells. Every one of them has its own positives and negatives. For example, the pouch cell is very good when it comes to energy density on a pack level because you can squeeze a lot of the pouch cells in the smaller space, but the pouch cell is not very good when it comes to mechanical integrity. So you can penetrate it quite easier than the prismatic and cylindrical. Prismatic is better when it comes to mechanical, when it comes to how it can be, how to say the exact correct term. It can take better mechanical stress than the pouch one. And cylindrical is more on the prismatic side, so it has a strong shell as well. But the cylindrical is not really the best when it comes to energy density on a pack level because of its shape.

13:47So you will have spaces between the cells. So I worked with companies who work with cylindrical, like Tesla was working with cylindrical and still. And I worked with companies working with pouch, I worked with prismatic. So I don't have a specific understanding of why specifically a company will use this and not that because every one of them has its own positives and negatives. I'm not sure really if the industry, like five years ago, like in the industry of cells, a lot of people were telling me we are moving away from cylindrical, but I still see companies using cylindrical. So I don't have really a strong opinion there where one of them will leave and the others will not leave. Maybe that can be a point if we have more experts in that part. Sorry, I want to see if someone is raising hands because I cannot see. Okay, I will continue. Just a small point because you will hear it also in the news and industry a lot.

14:52Cylendrical cells, they have a specific way for naming specifically for cylindrical. So for example, the two most famous in cylindrical is the 18650 and 2170. And basically this 18650 means that it has 18 millimeter diameter and 65 millimeter height. When you look for example to the new Tesla cell, the 4680, it means that it has 46 millimeter diameter. So it's like bigger, but it's shorter. So it's 80, sorry, and it's longer. So it's 80 millimeter. So it's important to look at these numbers in that way. If you will meet a cell, then you can know directly 18650. Okay, it's 18 millimeter and 65 millimeter. Like that. I don't think that's important. I can ask this one. Yes. One more point. When you are building a cell, you cannot really build a cell up until now, up until my knowledge. You cannot build a cell, which is energy optimized and power optimized in the same time. Normally, when you build a cell, you are trying to choose, am I interested more in building a cell which is optimized more for more power or one optimized more for more energy and less power?

16:18So you cannot get really both because of the way that you build the cell. Like, will you put more emphasis on having more current collectors, which is the kind of wires, not really a wire, but just for simplicity, kind of wires that will collect the current or you will build more of those which will give you more power or you will minimize number of current collectors and focus more on adding more active material which will take the space and then it's an energy optimized. So that's very important. The cell itself can be power optimized energy optimized. I'm not aware of any cell which is both power and energy optimized, but also if someone knows about it, please let me know. Last two points. The first one is to make it simple. When you are saying the amount of energy inside the cell, that's a very tricky question because if you're driving your car, the amount of energy inside the battery pack is different from the amount of usable energy at the current moment in time.

17:33So if you're driving your car and you're consuming 100 amps while driving now, if you will reduce the current instead of discharging by 100 amps, you're discharging by 50, you can in fact get more energy out of the cell. So that's very important that if you, for example, are using the battery pack at 100 amps and then you stop and arrest the pack and then you start to drive again at 20, 30, 40, 50, you can in fact get kind of more energy. It's something called the recovery effect. But it's important that you, for example, if you're driving the car, it can tell you you can drive 200 kilometers more, but if you change your style of driving, then you can get more or you can get less. So that's very important. It's not that the estimation is wrong, but it's your style is wrong. It's not a fuel, you are not really, it's not a fuel gauge where you are measuring fuel, you are estimating the energy.

18:37So that's very important. With batteries, we are estimating a lot. We are basically measuring three main parameters. We are measuring the current, we are measuring the voltage, we are measuring the temperature. Sometimes you can measure the resistance, but it's not something that is common in the industry. But we measure these three, and then we estimate a lot of things that you see in front of you. They are estimations, they are not measurements. that's very important to know. Next is, I can skip, maybe very fast, but the cell itself, a bad and a good cell can be because of the age of the cell, which temperature are you using this cell now, and which temperature have you been using the cell before? What is the state of charge of the cell? What is the material that you use to develop the cell? Are you using cobalt? Are you using nickel and manganese and cobalt NMC cell? Are you using NCA cell? Are you using LFP? Sorry.

19:46Okay. I can continue. Are you using LFP cell, like lithium iron phosphate cell? Material selection is very important to determine the performance of the cell, among other things, including age and temperature and set of charge, etc. The last point is the age. So, normally, the cell can age according to our main factors affecting the age of the cell is the temperature that you have been using the cell, the pulses or the current that you have been drawing from the cell and to the cell, and the current and temperature and the state of charge or the window that you have been using the cell. So, have you been using the cell from 0 to 100 instead of charge, or you are using it from 20 to 80, or you are using it from 30 to 50? So, this window also affects the cell aging, the temperature and the current and the window of the sock window. also if you have a mechanical stresses or something like this, but I don't expect it to happen in a car like this because it should be protected.

21:08Last thing is, no, I can say that that's okay for now. I think I covered what was needed and I can take questions and also Milo's joint. So, I can take questions and other of the interviews. Thank you. Thanks so much, Basim. I think it's so great to have a session like this to really cover the overview of batteries. I think we haven't had a session like this before, so thank you so much for covering all the details of battery cells all the way to battery packs. I would just like to also invite Milo's and Marla who have joined us on stage to maybe share their views on this. Milo, would you like to go first? Yeah, maybe I can go first. I think the most common mistake what the people are making is a mistake between power and energy. So, can you, obviously I know it, but can you explain the difference and also measurement difference between the power and energy? Sure, I can try to take the analogy that I used to study, at least like this.

22:27 I think the difference between power and energy, so if we have a bucket of water and it's filled with water, the amount of water inside this bucket is the energy, but if you are throwing water out of this bucket, you are not throwing the water all at once, you are throwing the water a bit by a bit. So, whatever you are throwing out, that's the power out or in of the battery, and the whole bucket is the energy of the battery. For the power, mainly it's in watt or kilowatt, for the energy, it's in watt hour or kilowatt hour. Do you need more details, Myles, or that's enough? I mean, I know it, I said that. Yeah, I understand, I understand. but I mean, you need something with more detail or where the confusion comes from? I don't know, there is no confusion for me, but when I hear many people talking to me and they are mixing up power with the energy. So, power and energy are related, but they are not the same.

23:35And power is measured in watts and kilowatts and energy is measured by the kilowatts, kilowatt hours, watt hours, and kilowatt hours, and so on. And also one more point, I remember now, is that when you are building a battery pack, like let's say that we are trying to build a battery pack, which has its own constraints. So, if you are a battery manufacturer, and I say battery, again, it's a battery pack, not cell. So, if you are a battery pack manufacturer and then a car, an OEM will come to you and ask you for a battery pack, they will come and tell you we need this form factor. And the form factor is mainly like the size, like the length and width and height, and also the weight, et cetera. So, they will come and tell you we need to have this form factor and this weight. power and then power and this battery pack should be able to fulfill this power profile. And this power profile related to their performance, how fast they will do like the vehicle to accelerate, how much energy should this battery pack be able to gain when they break through the regenerative braking, which is when you use the electric machine, which is the motor, but it's better to call it electric machine because it does both.

25:00It's a machine and it's a generator and a machine. So, it's an electric machine. And then you are using the electric machine to brake the vehicle instead of using the brakes itself. So, they will come with you and give you this profile and then you need to fulfill it. And then you will either have a vehicle which can go very fast. I mean, I'm talking here about using the same size and using the same weight. So, you will be able either to have a vehicle which can go very fast, but at the same time it cannot go as long at the range or how many kilometers can it cut or can it task in one charge. It cannot be the one which can go the fastest and the one that can go the longest if you are using the same form factor. So, that's also very important. Yeah, another very important part is how do you get power? Basically, you are going to get power when you are multiplying voltage by current.

26:00So, you are multiplying volts, which is measured in volts, and amperes, which is current, you are going to get power. And how you are going to get the energy, you are multiplying voltage by capacity. Capacity is measured in ampere hours, and voltage is voltage, so energy is multiplied voltage by the capacity. Yeah, thank you, I think that's, and also, what was more, yeah, very important part as well is that when we develop a battery pack, we say we would like this battery pack to fulfill this power profile, which comes from the OEM, but then we need to make a deal with the OEM saying, because now I'm working in OEM, but before I was working in a battery pack supply. So, if a battery pack supplier, then the OEM will tell you, I need this battery pack to live 8 years, 10 years, 15 years. And when you have this, then you will start to talk to the cell supplier, give you some tables, which is related to the performance and safety.

27:11Then you will start to build your state of power algorithm, because the vehicle listens to the battery. So the battery will tell the vehicle, I can give you now 100 amps, or I can give you now 120 amps, and then the vehicle will take this power, and we estimate the power that the vehicle can take or give to the battery pack, which keeps the battery pack within the safety limits, as well as the health related limits. That's very important. It's not something that we measure when we are working with battery. We don't, I mean, we measure the power that's being drawn out of us or towards us, but we don't measure how much power can we give, we estimate, and that's very important, because if you do the wrong estimation, you can lead to either burning the battery, or you can lead to a degradation, health degradation very fast. So the battery, instead of living for 10 years, it will live only for five years.

28:12And I mean, live here is, maybe that's maybe one important thing to define. There is something called end of life, and this end of life is something that the battery supplier with the OEM or the vehicle manufacturer decide together, but mainly in a lot of companies, it's 80 or 75 to 80 percent of the state of health of the battery in the beginning of life. And the state of health in most of the companies is linked to the capacity loss of the vehicle. They also put one more condition when it comes to resistance increase, it's around 150 percent, but mainly they focus on the capacity loss. So when they say that when the capacity of the battery pack is 75 or 80 percent of the capacity of this battery pack in the beginning of life, then this battery pack should not be used any longer. It should be maybe taken into recycling or a second life or something like that. Any questions or something? Or reflections?

29:19Is there any use of super capacitors in the, I guess, car batteries for, I guess, like starting it? The use I saw for super capacitors was mainly for instantaneous power. So the part of the battery, because the battery is electromechanical system, electrochemical system, electrochemical system, you cannot have instantaneous power very high. I don't want to Yeah, but I mean, that when you look, for example, that you want very low amp power. That's another common mistake. Yeah. So when you are saying, for example, I want to break, for example, I worked with trucks before, okay? One big problem with trucks is that you want to break the truck when it's going down a slope. That's a legal requirement on trucks. And then you cannot break using the battery because the battery cannot take that much power suddenly. It has a limit on the power, and this limit is based upon the estimation we did. Then there, one of the solutions, I'm not saying that you do it, one of the solutions can be that you have a supercapacitor which will take the excess power from the electric machine, and then you can use it later on for any usage.

30:50You can either charge the battery with it, or you can use it for the electric machine. So you can basically put the supercapacitors in parallel with the cell, or with the battery. The problem with supercapacitors is that they don't have enough capacity, and at the same time, they are expensive. But there is a lot of companies who are talking about using them. I'm not aware of any companies using them. Sorry. Batteries are getting better, power, so they are getting better also in the power density. Basically, we don't need to use supercapacitors in many cases, because capacitors generally, they have much higher power density, but much lower energy density. So, basically, capacitors, you can accelerate very fast, very fast with the supercapacitors, but it will not last for a long time. And the battery is opposite way, like Bassem said in the beginning, because battery generally doesn't have a very high power density, but it has high energy density. Yeah, I've seen some stuff where they use the supercapacitor to start the car, but generally, they use a chemical battery for most of the usage.

32:22But when you mean to start the car, do you mean to start the hybrid battery? Yeah, like hybrid, just to start the car, because yes, the energy density is very low. No, you mean the power density, so it cannot provide enough power to... Okay, because when you say start the car, I mean, for me, in that industry, when you tell me start the car, I would say, are you using it as a 12 volt battery? But no, you're using it for acceleration, like in the beginning. Yeah. It's a choice, but I would say that you will pay money and you will pay space for it, and then you need to really, maybe you can have it in sports car, like a lot of sports cars, like Remax and different ones, which are really looking at the milliseconds, like I want to accelerate in one point whatever second from 0 to 100, like now. So that's something where you can use it, or you can use it, as I mentioned, for regenerative braking when you have dumping a lot of load due to braking like a truck or something.

33:25But it's still not something that's being used, or I have not seen it very common. It's not that common. Yeah, it's expensive. Yeah, exactly. I just thought it was cool because it was one of the solid-state batteries. Oh, solid-state. I don't know if you have a lot of, I mean, for me, solid-state batteries is something that will come in the future, but it's not going to come anytime soon, according to my following. I'm following quite a lot of different companies, but I don't think it's coming in two years or something. I don't believe in that. solid-state is not yet commercialized, and it may be not commercialized ever because we are trying to build solid-state batteries already for 50 years from the beginning of the lithium-ion battery. But for 50 years, nobody was able to do it, and up to now, nobody is able to do it. Yeah, I think it's a very good point, because I think you will see it a lot in newspapers, or newspapers related to EVs, and they mention breakthrough, like four times the energy, five times the power, but it's all in the lab, nothing manufactured yet.

34:48But a lot of companies are talking about 2025. I highly doubt it, but let's see. yes, there is another thing, a lot of hype and exaggeration in battery space. I was talking a lot about it previously. Thomas Edison warned about it more than 100 years ago. but another thing is that those solid-state batteries, they are not even claiming right now, even QuantumScape, that they have solid-state battery in laboratory scale. So it's not working even in the laboratory scale. Their solid-state battery, which is based on the so-called solid-state batteries, not solid-state, because they're claiming that they invented separator, not electrolytes. Electrolytes are still semi-liquid because they are gel electrolytes. They are not solid-state electrolytes. And they didn't disclaim to anybody what kind of material they are using for separator. Yeah. At one point, a lot of companies are investing heavily in that. A lot of companies. Because it will increase, it should increase energy and power and safety. So a lot are investing in that, but nobody reached yet.

36:14Thanks for the discussion, everyone. I really love how we went from the basics of batteries all the way to the forefront of battery technology. And solid-state is always a really hot topic in this room. So we will probably have another session on solid-state as well. I would love to pick up on that and explore different types of solid-state as well. Maybe we have Marla, who has joined us a stage a while back, to share her thoughts on this. Yes. Thank you, Retrin, and thank you for the talk. So I will go back, jump back to the basics. I had a question, actually. My question was regarding the effects that the phenomena that affects the aging of the battery, as you mentioned, temperature, state of charge, window, and so on. And I was wondering what is the contribution of each of them? For example, if I limit my SOC window to be flat, to be a flat resistance over this window, how much I would expect to see improvement in terms of performance?

37:22Well, I would say this is a $1 million question, because I am not aware of any company which was able to say exactly answer this question. So we just know that if you increase because a lot of these conditions are super intertwined, so they are not really separate where you can say it's a multidimensional equation that you need to solve. So you have the temperature, but the temperature also affects other things. So if you are having very high current, then you will have higher temperature increase inside, which can lead to that and this. So a lot of things are linked together, and then when you affect one, you affect the other without really knowing the one. I'm not sure if we have any. I'm not a cell expert. I'm not sure if we have any cell experts who say, yeah, we found out, but I'm not sure if any company did it before. Yeah, the battery, there is no one factor which you need to when you are trying to achieve.

38:27The quality of the battery, you have at least 10 factors which you need to balance them. You need to, everybody is trying to do high specific energy, high specific power, affordable cost, long life, safety, wide operating range, toxicity, fast charging, scalability, how fast you can, how big volume you can produce, recyclability, self-discharge, and so on and so on. I'm just echoing the point that Bustin mentioned earlier as well. It is very difficult to actually have a direct relationship because also considering the fact that battery cells, they don't operate in silo when they work in a pack. the arrangement of the cells and also how densely the cells have been packed in the battery pack will have an impact on the performance of the battery pack as a whole. It is a difficult question. It also depends on the type of battery cells and the type of thermometrium that they have as well in the pack. Maybe just to give you a flavor of what are some of the factors that would affect SOC and SOH in general.

39:53Speaking about that, maybe we can also have a little chat about SOC and SOH and residual usable lifetime. I think you've mentioned about that earlier, but if we could give some definitions to that to the audience here, that would be great. you mean to start with the state of charge, state of health? You mean the state of charge? Yeah, yeah. Yes, so the state of charge is the amount of energy left in the battery pack compared to the amount of energy when the battery pack is completely full. So when you're saying the state of charge is 20%, then you should have amount of 20%. I don't want to say capacity because some people can mix it with the health. So it's amount of 20% energy left compared to when the battery pack is fully charged. Maybe it's not the most correct scientific explanation, just as disclaimer, but just to keep it simple. the second one is the state of health. And the state of health is the health of the battery pack.

41:11And this is something that, per my knowledge and what I follow, there is no international definition per se. But the two common definitions that are being used is the loss in the capacity. And I mean here the capacity of the cell compared to the original capacity in the beginning of life. So when I say that the battery pack is 90% state of health, it means that the battery pack has lost 10% of its capacity, its capacity that you cannot gain anymore. You cannot, so for example, if this vehicle had 100, sorry, if this cell had 100 amp hour capacity, then it will have 90 amp hour capacity and you will be able to use this 90, not more. the other thing is the increase in the resistance. And this increase in the resistance because the battery, the cell has resistance and this resistance increases with age. It increases when you use a cell outside its optimal range. And the range here is related to temperature, it's related to the current and other factors, but let's focus on those.

42:25Then the resistance will increase. And then when the resistance increases, then this can be used as okay, now my resistance is 110% of the original resistance in the beginning of life. Normally manufacturers, they put limitations on the state of health when it comes to the capacity loss and the state of health when it comes to resistance increase. I know from a couple of suppliers that the problem is that after 80%, the how to say, the behavior of the cycle goes way up higher. No, I'm talking now about state of health. Because now the next thing, when you are saying that the battery is 90% state of charge, then you are having a 10% left that you need to charge to be fully charged. But when you're saying 90% state of health, then you cannot charge on more than the 90%. The capacity is lost because of a lot of things. I don't want to enter into this because it's quite dense, but you lose the lithium ions, so you cannot really use them anymore.

43:43They are lost. The cycle of lithium is lost, so you cannot really use it anymore. But back to the point, the manufacturers, when they reach 80%, a lot of them say, after 80% or 75%, I cannot guarantee the behavior of the cell. I don't know what will happen. Because when you look to the curve, you see that it's flat and then up until 80% and then suddenly they say it's dropping very fast. We cannot determine it. Maybe something will be better in the future. So they normally stop at 80%. The lowest I saw was 70%. After 70%, they will forbid you from using cells. what else? And again, the factors are temperature and current and state of charge window. And one more thing is one more point also is that when we are calculating, not calculating, that's the wrong word, when we are estimating, we are not calculating. It's very important. When we are estimating the state of health, we mainly look at two things.

44:49We have something called cyclic aging and we have something called calendar aging. So the calendar aging, let's start by the last because it's the easiest. The calendar aging is how many years have this cell lived since production? Because the cell, it ages with time. You are losing cyclic lithium just by the cell standing still. And the second point, so you cannot really save a lithium-ion battery for, I don't know, 100 years and say that the health will be the same. cyclic aging. And the cyclic aging is the aging that takes place due to charging and discharging the cell. Because physically, if you are having a dough, like a cake, you're making a cake and you're having a dough, you are basically, when you are charging and discharging, you are pushing seeds inside the dough and taking the seeds out of the dough. And this dough is basically expanding and contracting. And then doing this, you get cracks, and then when you want to fix these cracks, you are using lithium-ions to fix the cracks, and a lot of things happen.

46:08And there you are losing the cycle of lithium. You are losing it. I'm not sure if I went too far. Yeah. I think we should say that most movable part of your iPhone is battery, inside of the battery. You know, battery is never static. Basically, battery, lithium-ions and other elements of the battery are constantly moving, especially by the charging and discharging. So battery, a single battery, it's like electrochemical factory in very small space. Thanks so much for the explanation, Basim. I think that was super detailed and very helpful to everyone here as well. Maybe let's move on to Bharath. Sorry, Yue. Yue, do you have any other questions? If not, I'll move on to Bharath. Oh, one more. I remember reading about a new, I guess it's an old chemical battery that they were talking about that was very caustic, but they're talking about using a new casing for it. Do you know which one I'm talking about? It might have been sulfur or something.

47:30I heard about lithium sulfur ones, but are you, I'm not sure that I have the detail about it. It needs to be someone working with cells mainly. I'm not sure if Simon and Catherine have heard about it. No, not myself to be honest. Is there anyone in the audience who knows much about it? Doesn't seem like it. Maybe we can check on that and answer you offline or in another session. Yeah, I will have a look at it as well. here. Let's move on to Bharat. Yeah. So, hi, this is Bharat. Actually, my question is that when we started consulting with various startups who are working on a different space, everybody was looking towards a cooling system. in India especially, we work with two-wheeler and three-wheeler companies and also energy storage companies and things like that. So, I just want to ask you a question. Do we really need this cooling system for energy storage sectors or do we need only this kind of cooling system for the automobile industry where the dynamicity of the load is very high in the battery?

48:52That's my question always. And what is the effective cooling system? Because someone is proposing immersion cooling system. Someone is proposing some different cooling system. So, what is your view on it? Okay. I would say as follows. So, basically, the battery pack or let's say the cell from the cell because it's mainly the cell. The cell would like to live or lithium-ion cell would like always to live in the temperature where we are really happy as humans. So, it's around 25, 35 degrees. That's really nice. Catherine, you want to add something? No, I'm just applauding to that because that's literally how I explain to my clients most of the time for battery-thema management system. So, when we are looking, we are looking to this to be between 20 to 35, 25 to 35, in that range. and when we are talking about if we need, well, it depends on which power profile are you going to use it, which means how you will use it, how you will dimension the battery pack for that, are you going to use more cells in parallel to have more power on a vehicle level while having very low power on cells, which means that you are spending so much money which is not needed.

50:13So, basically, you need to keep them between 25, for 20 to 35, for 40, for example, which is the optimum. And if you, would you like to use supercharging or you don't care for supercharging and you're going to use it for a very slow charger, what is that ambient temperature outside? Because, for example, we have the Nissan Leaf, it used to have cooling, it used to have like air, and it's not really effective, and a lot of customers were complaining about it. So, it's more like what is the most important attributes? Yeah, you are going to save money and space by not having a cooling system. You are going to have a higher energy density on a battery pack level by having no cooling system because you will have more space to put more cells if you would like to. But you know that your battery pack will not live the same amount of years that it should have lived with a thermal management system.

51:09also, if you have a very hot outside, are you planning you as an engineering company to tell the customers that if it will reach 55 degrees, I will disconnect the battery pack from the vehicle and then the vehicle will be stranded in the middle of the highway or on the side of the highway because it's very hot outside. So, this is a lot of questions that you need to answer before taking the decision out there. Yeah, that's the same thing which is happening because a lot of government tenders and a lot of government discussions are happening in various parts of the world, but many companies are not providing the right data regarding the cooling and things like that. So, many people are asking us regarding the immersion cooling technology and things like that. So, that's it. And one more question is that do you think this battery management system is one of the crucial component in maintaining the thermal and electrical input and output? So, actually the main thing is that many people argue if we develop a very good quality battery management system, we can neglect the cooling system by means of having a very strong battery management system.

52:19Is it really true? Is it acceptable? Or just to clarify my conclusion? Okay. Mainly I work with battery management systems for almost all my work with batteries. So, the battery management system is the brain of the battery. It's the system that measures the voltages, measures the temperature, measures the current, measures other things, make all the estimation, the state of charge, etc., etc., etc. But this system is not an activator. It cannot reduce the temperature. So, for example, I can say like this, the battery management system can keep or can try to keep the battery pack within the temperature limits. But how it will do this? It will do this by reducing the power. So, when it will see that the temperature is reaching 45, it will tell you, okay, you cannot get the full power, you will get only 80% of the power. And then, if it's going higher, it will tell you, okay, you cannot get 80, you will get only 50% of the power.

53:22And if you will not obey the battery management system and you will continue taking the 100, the battery management system will open the conductors. So, you will lose the propulsion. And the second, for me, I believe, maybe it's an exaggeration, but I think the battery management system and the autonomous driving system will be the most, or almost now, the most important system in the vehicle. Because if I am able to save 1% in state of health of the battery, in my estimation, I can save millions for the company. If I can save 1% in a state of power or not 1% in a state of power, or I can save 1% or 5% in a state of charge, I can save millions. If I can control the battery good enough that I can live longer, I can save billions. So, for me, it's one of the most crucial systems in the vehicle, not even the pack. But still, it is a system that monitors and controls the contactor.

54:25So, the battery management system cannot do anything more than opening contactor. It's the only the last defense it can do. It cannot force the vehicle to take a certain amount of power. It politely asks the vehicle, don't take more than X, don't give me more than Y, but it cannot physically force the vehicle. It can just open contactor. So, yes, it can control the temperature to a certain way, but it will control it in a way that will not make you as a customer happy because you will not be able to accelerate properly because I limited the acceleration or you will not respect as a vehicle, you will not respect the limits and then I will end up opening contactor and then you are on the side of the road. Yeah, thank you so much for this. I hope I answered the question. Yeah, exactly. Thank you so much. And one more question. I'm just curious about is it necessary that many companies in India, I don't know, because you have a very good battery analytics companies and things like that, but second world countries like India, Afghanistan or Pakistan or some other countries, they are not using any battery analytics in their products, not even in their automobiles, not even in the energy storage system.

55:41So do you have anything to say? What is the necessity of having a battery analytics connected with your product which has a battery? Yeah, I think it's a very very important. I think it's data analytics, in fact, it's very important in almost every industry, but when I look to the batteries, I would say that if I will be looking at analyzing the data that I get, for example, I would see that very simple example. If you look at the users that are using the battery packs, most of the personal vehicles users, they basically will play in the 100 to 80, 70% of the window, the charge window, which is not the most pleasant window for the battery. The battery would prefer to be in the middle, not at the 10, 20%, not at the 180%, it would prefer to be in the middle. But if I will analyze the data coming from the customers and I can see that they are always driving, some of them or most of them, they are always driving a short distance and then stopping to charge and then driving a short distance and then charging again at home, then they are keeping the battery in the highest state-of-charge window, which is not very healthy for the battery.

56:55Then I can suggest to them, hey, if you are going into your daily trip, you can always leave the battery within the 50 to 70. And when they are going into a long trip, then they can activate the long trip mode and then they can charge up until 100. And like this, I can prolong the health of the battery. But if I don't know the usage, if I'm not analyzing the data, I will never know an information like this. And much, much, much more can be used. I can see what the customer is doing and then I can optimize my algorithms towards the customer. And also this data can be used for modeling because we have a lot of models inside the battery management system. And if I have that user pattern, I can use this as a train the battery management system. If you are talking about AI, for example, battery management system, I can train the battery management system on the real data that's in use.

57:58Yeah. Thanks for the comment. It's really helpful. Yeah, but you need always also the mechanical physical stuff because battery management system needs to manage something. So basically, if you don't have the what to manage, battery management system cannot manage. the of health of health Maybe just a quick add here. Some of the battery packs that we have seen as well, especially with two-wheelers, they adopt for the podcast. It's also on BatteryMBA, so feel free to check that out with Simon. I do have a national question on this topic. And just with the use of battery packs and active, you've seen OEMs using active BMS to kind of stabilize the pack. And how often is it? Catherine, I'm having a very hard time to hear you. Is it only my connection problem? I think it's me as well, so I think it might be your connection. Catherine, can you hear us? Maybe in the meantime, maybe your internet is acting up. Quick question, because you already maybe addressed it a bit.

1:00:25You know, you talk a bit about state of health and things like this and state of charge. I mean, one thing for me quite interesting is also the point of what actually counts as a cycle, right? Especially when you look at usage and we spoke. I spoke to a few people from different companies, etc. I was just curious maybe how Basima, how you see what is a use cycle? So, like, you know, like, because of course, I mean, the reason why, because you mentioned earlier as well, right? People wouldn't usually completely discharge and completely charge their car or something. And of course, there's different implications, right? If you completely charge it, discharge it, or if you're like only partially charging and discharging and you add these ones up as a cycle. But this, of course, could be less demanding as actually fully discharge and charging it. Not sure if this made sense, but that's something I'm just finding fascinating. And Basima, if you have some thoughts on this from an industry perspective.

1:01:10Yeah, I saw. So, I mean, I saw two different opinions. That is that one opinion was taking that one charge, or maybe that's the most common I saw, was that you wait until you finish one full charge. So, even if you did charge, discharge, little amount of charge, little amount of discharge, like if you're going 10% up, 10% down, 10% up, 10% down, they relate until you do it 10 times and then you've finished your cycle. So, it's also a problem when it comes to data logging. Like, what is, like when you are saying, you will, we will do this every drive cycle. And then we are saying, okay, what's a drive cycle? So, we have this, I saw it in different companies, doing different things, but I think the most common I saw was that they wait until you charge or discharge the full capacity or the full current, and not current, because current can be with current, the full present capacity of the pack.

1:02:11So, if the capacity is 100 amp hours, then when you are, when you discharge 100 amp hours, then you finish, and then you charge one amp hour, then you finish one cycle. I'm not sure if you saw something different. Well, that's something else I've heard from some companies. So, yeah, just something I find fascinating, as you say, because I think different organizations and companies do different things. I also see Jonas is on stage, and there's also Stefan trying to come on, we're trying to get you on, but it doesn't work. So, Jonas. Yeah, so I have a question for Basim. You seem quite knowledgeable about the BMS systems. Maybe you could explain to us a bit on the role of the BMS in terms of balancing cells and keeping the voltage level between modules and such. Oh, that's an interesting question. Very good one. So, I think, when you are looking to a battery pack, and then you have cells, they are all in series, and then these cells, which are in series, they are having the same current through them, charge and charge direction, but due to a lot of fat reasons, like temperature difference, like age difference, and other chemical reactions inside the cells, you will have, these cells will have different voltages after some time, so they will deviate.

1:03:33So, instead of having all the cells having the same voltage, you will have some cells with higher voltage than the other. And this is something that you cannot have because you will basically lose kind of capacity of the whole battery pack because when you are trying to charge, the cell with the highest voltage will be the limiter for you. So, you will charge until this cell reaches in the best case because if you don't know that this cell having a higher voltage than the other, you can in fact go into cell venting or even a thermal runaway and fire. So, I'm talking about the best case that you measure and you know everything. Then you will reach that your cell with your charge of charging and then the cell with the highest voltage will hit the limit and then you will stop charging. But the rest of the cells, they didn't fully charge. Then you are losing capacity and you are not using the full capacity of the battery pack and then when you are discharging, the one with the lowest voltage will be the one that limits you first and then you will not discharge the rest of the cells inside the battery pack to the maximum that you should have done and then you are losing capacity.

1:04:37And there we have two ways. So, the BMS has two ways to do balancing. Basically, you have balancing between, sorry, we have passive balancing and active balancing. The passive balancing is the balancing that you do by connecting a resistor in parallel with the cells with the highest voltage. And then you burn this energy through the resistor. And when you burn this energy through the resistor, the voltage will drop inside this cell to reach the voltage of the lowest cell. So, you bring the highest cells towards the lowest cell. Okay? And this is by burning the energy, by connecting this resistor in parallel. The other way, and this is the most common way, I have seen almost in every OEM, I have went through there. And then the second is an active balancing. An active balancing is done by charging one cell from the other, for example. So, you connect one cell in parallel to the other cell and then they will balance each other. Or you can connect or you can have a capacitor in parallel with the cell.

1:05:49But this is expensive and not very, like you don't gain much more that can make you pay that amount of money to do the active balancing. One also, other domain which is people maybe don't look at, in previous companies, I saw before they used to call it online versus offline balancing. I'm not sure if it's industry-wide terminology, where online means that you are doing the balancing all the time. And offline means that you have to wait until the vehicle is standing still. There is no current being drawn from the vehicle for maybe 12 to 20 minutes. And then you can measure the open circuit voltage if you are with us from the beginning. It's something that I explained, which is the voltage on the cell when there is no current passing through it for some amount of time. And then you can know, because that's the true voltage, and then you can know, okay, I have this cell with this voltage, this cell with this true voltage, and then I will reduce the voltage of the higher cells to reach the lower cells by burning the energy through resistors.

1:06:58But the online one, it is something that a lot of companies are using where you are doing this balancing all the time. But this needs, you need to be super careful, because when you are driving the vehicle, the voltage that you are measuring on the cells, that is not the open circuit voltage, that's not the true voltage, that is the voltage of the open circuit voltage plus other voltages that are being built up through the resistors and the capacitors, okay, I don't know what to say resistors and capacitors, due to the phenomena inside the cell that we model using resistors and capacitors. so, for example, when you are having a cell which is quite old, it will have a higher resistance compared to the same cell when it was younger or like in the beginning of life, and then when you apply current, then you will have a higher voltage drop or a higher voltage increase depending on which direction are you applying the current, and then if you measure this, you're not really measuring the OCZ or the open circuit voltage, you're measuring the whole voltage, and then you cannot use this for balancing.

1:08:08So, one of the techniques is that you, I don't know, let's like screenshot, so when you are standing still, you look to the OCV and you know that you need to dissipate this amount of, you need to drop this amount of voltage from these cells, this means that you need to dissipate this amount of energy, and then when you start driving, you will continue dissipating the amount of energy because you know how much energy you would like to dissipate, you can calculate the amount of current going through the cell, and then you know that, okay, fine, I will dissipate this amount of energy, and when I finish, I will stop. And then in the next cycle, when I stop the vehicle, I will look at the OCV again, and then see how much balancing I need to do more. I'm not sure if I took that. That was absolutely good. So, would you say then that I would actually prolong the lifetime of a battery pack with having proper BMS than just taking care of the voltage regulation as well?

1:09:09Yeah, I mean, balancing can be quite bad if it will, like, normally they talk about 500 mV as maximum level, but when it comes to talk about health, I'm not sure really about the health in that fact. I mean, to be pragmatic, you can still keep the battery in a good health, but you will lose really a lot of the capacity because you will keep hitting the limits up down very fast, so you will not have really a very usable battery pack, but you can still have a healthy battery pack, but not usable. The other problem can be if you are having a battery pack with old and new cells or old and new modules, which are connected in parallel. And for example, if you are talking about the kind of old architecture, when you have cell to module, module to pack, because a lot of the companies now, maybe it's something that we need to look up next time, Catherine, which is cell to pack, like Tesla and other suppliers are talking about or other OEMs are talking about.

1:10:11So if you talk about the old style, when you have cell to module, module to pack, and then these modules are in parallel to increase power, and then if one of the modules died for somebody, then you should not always put a new module, because maybe it will be more beneficial for you to use the rest of the battery pack as a replacement, like a spare part for other battery packs, because if you have a battery pack with all the modules are 90% or 85%, and then you throw in a new module, this module has a lower resistance, and it's connected in parallel, it will take more current in the charge and discharge direction, which will lead to this module going to edge very fast compared to what should have normally happened to it, and then you are basically burning money, then you're basically burning money by just putting a new module to an old module, it's the same as if you have more than one battery pack in parallel, if one of them will die, it's not always the smart decision to replace it with a new one, you can replace, in fact, the three or four battery packs left, you can replace five of them or four of them, all of them, better than replacing one of them, and it's a very, very tricky question to answer.

1:11:35Yeah, when looking at, for example, old leaf models, it seems like they were suffering from not managing this correctly, as some cells would pretty much be depleted, while others were more or less at full charge, so what we saw was that we could do a manual recalibration of the entire pack, by slowly discharging it, and doing slow charging back up to it several times, and by that actually waking some of the old cells back to life. Yeah, but will this be a permanent solution, or it will, I mean, is it a permanent solution, or you will have this coming back to you very fast due to the age of the battery pack? Because I'm not sure if this was due to age as well. Well, we haven't seen it come back on several of the cells, but it seems like the previous owner of that specific car didn't manage his charging good. He depleted the entire battery pack, and he charged it full with quick chargers, and so on.

1:12:44So just recalibrating with slow charge seems to have woken up a few of the cells back. probably some built-in protection there of having someone in too long. But I would say just a small comment here, I would say that from an engineering point of view, I would say the customer should never be able to harm the battery. I should have the control. So if I don't have the good algorithm, then the customer should be able to do that. But if I'm doing a good engineering and good battery management system, I will stop the charging, I will stop the discharging at a certain limit. I will not reach a deep discharge, and I will not, because one of the things, there is something called lithium plating, I don't want to start it now, but it's some kind of a phenomena inside the cell that can lead to cell venting and fire. And one of the ways to do that is by having deep discharge and then fast charging, or fast charging at very low temperature, among other things I know about this too.

1:13:50So me, working with battery management system, I should have enough knowledge to build a good battery management system that will protect against this behavior of the customer. So that's very important that from an industry point of view, the customer shall not be able to horn the battery unless he or she will come and throw it with fire or destroy it with some mechanical force. But I should be in control or we should be in control. Yeah, and what I'm talking about here is a really old car as well. It's a 2013, so it probably wasn't the best technology-wise either back then. I agree, I agree. Lauren, thanks so much for joining us. We have Lauren also joining us. And if you're actually the first one, today we discuss battery basics. We have Massim with us, many other battery experts on the stage and the audience. So if you have any questions you ever wondered about, either an understanding question or what does something mean, we need to raise it now.

1:14:52I have a question about batteries generally in the EV space that we see a bunch of vehicle manufacturers, I think Mercedes and Lucid Air are using nickel-manganese cobalt 811 battery chemistry and I don't know if we know how long the life of these batteries will be. I don't know how long NMC 811 has been around, how thoroughly it's been tested. How good their battery management systems will be to preserve the long life of the batteries. You know, Teslas have been using some kind of nickel-cobalt aluminum chemistry that they really have a lot of experience with. So I was just curious whether people have any opinions about particularly the cycle life of NMC 811 and how important is a good battery management system and do they have adequate battery management to maintain cycle life. Well, maybe what I saw before, I think, I would say that from what I saw and worked with, I think I worked with mainly NMC 111, but when it comes to 811, I saw it with previous manufacturer, I can't say who because of the policy, and I think it's more of the thermal stability that is something that worries the people about the 811, one, but the battery management system should be the one handling this.

1:16:38I did not see a very long time testing for these cells. They did hundreds of cycles and it was quite okay. I'm more worried, I would say, as now I'm working with safety for some time, I'm more worried about an NCA cell than an NMC cell, in fact. So I will worry the least about LFP, worry more about the NMC, and worry the most about NCA. So, but I did not see like a vehicle with very long time, but I know that a couple of vehicles in the street already have this in 811. So, which vehicles have 811 already? I cannot say that because of that, yeah, they did not share it, so I cannot share it publicly, but yeah, a couple of ones in the last two years. Are they on the road today and being sold to customers? Yeah, two years ago, like from two years ago, exactly, because I know the cell manufacturer, so when the cell manufacturer sold to those ones, so, but it's not, I mean, I think I would, I don't know, sure if some cell experts can share their opinion there, because for me, the NCA is more dangerous than NMC.

1:17:59Well, the thing with NCA, I'm not talking about dangerous, Tesla's been using NCA for a long time, and I think they've demonstrated adequate reliability, and particularly some of their vehicles have lasted, some of their battery packs have lasted hundreds of thousands of miles or kilometers, where I don't think we've seen NMC, and I don't know what you're referring to, so I can't respond to it, but I don't know if we've seen NMC 811 in any volume, you know, maybe it's a low-volume manufacturer, maybe it's a limited application, I don't know, you know, the thing with EVs, one of the advantages of them is if you can get them to last, let's say 500,000 miles, then you can amortize the cost per mile over 500,000 miles instead of 150,000 miles, and that makes the vehicle a lot more attractive. If the cycle life isn't high, then, the battery pack doesn't last as long and you have to amortize the vehicle over, or the battery pack anyway, over a shorter lifetime, and that makes the cost per mile higher.

1:19:07So that's, you know, I just, I see it particularly with Mercedes-Benz EQS and Lucid Air and maybe there's others, and they're both using LG Chem as far as I know, but I just was curious, and I don't know if anybody else has an opinion on that, you know, do people think that's an important question? Do people think there are solid answers on it? Maybe, also, I can chime in here and just give one other thought on this one is, as you mentioned, you know, like Tesla, et cetera, and I mean, one thing also why Tesla's last that long is because the batteries have been quite oversized, right, just in the dimension, and then, you know, you can use the BMS and you can do some nice cell balancing and you really, you know, you really can reduce, let's say, the issue on your cells. If you have a very small battery pack, right, you have to charge it literally every day. Things like that it looks a bit different, so I think one thing is, one of the reasons why they've lasted so long, the Tesla batteries is because they've been, you know, really, really big and, you know, just on the capacity-wise it's been absolutely big.

1:20:05The second thing also, just really quickly. I'm sorry, Simon. I think, Simon, you are wrong. The Tesla from the established electrical vehicles, electrical vehicle makers, it's most efficient battery and power train. So, the other companies are oversized, like the Audi e-tron is oversized. I think Simon's point is, if you have a 300-mile range, then 2,000 cycles will get you to 600,000 miles. If you only have a 200-mile range, then 2,000 cycles only gets you to 400,000 miles. So, having a longer range pack means your cycles get you more miles. I understand that. That's what you meant, Simon? That's part of it, right? I mean, I agree with you, there's some other batteries now coming with much larger batteries. But if you just look at Nissan Leafs and things mentioned earlier, these batteries have been much smaller, right? That's one of the range, as you say, Warren. Another one is also just from, yeah, if you use it, let's say, most cars are used quite less, let's say, less than 300 miles a day, right?

1:21:20So, that's just one thing. Another quick thing I just want to add quickly, then I'm happy also for anybody else to chime in, is that chemistries are changing quite rapidly. It's quite interesting because I remember 811 was like, at least when we went in Cambridge and did our PhDs there and research, we didn't assume it would come anytime soon and then it became commercially much quicker. Now we can see 9, 0.5, 0.5, we can see NMX from S-Volt and other companies now, especially S-Volt companies now, claiming they can't go without cobalt at all. And one thing here is, as you say, the reason is that cobalt is one of these things you want to replace, one because of costs, but also from an environmental and ethical standpoint. But cobalt has been a great way to stabilize these cathodes. And it is something to be curious about. It's quite hard to compare these batteries at times because if they're installed in different configurations, different vehicles have different drivetrains, different driving behavior, different user groups, all these kind of things make it quite tough to compare it.

1:22:27But one thing maybe, Warren, you might be interested in, there's a cool tool. If you Google, and I will send you a private message, but for other people as well, if you Google Geotap and then degradation, they have essentially looked at all kinds of different vehicles because they're like a telematics company and they have been looking at the degradation of all kinds of different electric vehicles and also different versions of theirs, like different years, let's say, and when they were launched so they can see the change in battery systems, etc. It's just quite interesting to see the degradation. Overall, the degradation is lower than what many people expected, which I think you also hinted at. There are some tools, but I'm absolutely with you. It's a big challenge to compare in real market or in real environment conditions because all the vehicles are different, etc. And just one quick thing, I'm just looking at the time. We're almost at the end, so if you have a quick follow-up on Milo's, Warren, or someone else, otherwise we can also give a quick video to Srikant.

1:23:28Srikant. I say let Srikant go. Hi, everyone. I'm Srikant. I joined late for this session. I could not hear all of it, but what I understood about the discussion about the battery management system and stuff, and I mean, it's really important right now because we are seeing more and more cars getting caught fires. recently the Chevy Bolt had some kind of fire, battery fire, and it became such a big news right now because of even small accidents happening inside. EV causes much more outrage and stuff, and people really are looking for to find one mistake in electric vehicles or any such things. So what I think is right now we need to have the customers, the owners or the drivers really need to understand how the battery should work. The abuse of batteries really can be reduced by proper usage of the batteries, and we need to have a proper maybe recently because in the next decade it is going to be increasing. Every few months the amount of EVs sold is being increased, and it's really necessary for the drivers to know how to use the car, how to use the batteries, and we need to have much more details about the battery degradation inside the car or, for example, information for the customers so that they can understand how the battery degrades and not just suddenly catching fire and stuff.

1:25:17So we need much more than battery management system for getting a much more detailed analysis of a battery and then how it degrades. That's what I feel. What do you guys think about it? Just a quick comment here because the battery management system can prevent some external factors and some internal factors that leads to aging and leads to fire and venting, but a lot of the cases can be related to a cell fault. And here the battery management system, the maximum the battery management system can do is to warn the driver or to, if it's a thermal run away or it's venting and it's going to a thermal run away to warn the driver early enough so the driver can evacuate the vehicle. But the battery management system cannot always be the solution. So, for example, if we don't have, as I'm working with something called functional safety, I'm not sure if you're familiar with it, but this functional safety is related to the safety of the electronic systems, which includes the battery management system.

1:26:20But we cannot cover internal short circuit due to manufacturing defects. This should be covered by something called PFMEs and some other methodologies to make sure that we are using the correct way of manufacturing and cells and testing, et cetera. But I agree with you that we need to give the customer more data, but one problem I saw with customers is that if the customer does not know what does this mean, it can be too much information for them. So we need to find a very sweet spot where we can show enough but not too much. Yes, exactly. That is what, for example, I am working in a cloud-based battery analytics company and we really dig deep into the battery data from the, we get the data from the BMS and we really develop algorithms in a cloud-based environment. So we get even the short, very deep deep cell internal short circuit information from our analysis. So what I meant is, yeah, we need to have a sweet spot, but something like an app or something for the customers where, I mean, it should be go along with the BMS, kind of a solution, a cloud-based real time solution so that the customers get information as soon as possible.

1:27:36And yeah, that's what I meant about giving, initially, giving enough training for the customers. Some kind of OEMs should manage some kind of a workshop for customers initially, then it will catch on later on. And then once people get used to this EVs, then it become, as in any disruptive technology, the initial few years should be a kind of a learning phase for everyone involved. Hello, everyone. Just wanted to chime in here towards the end. I've been listening to this conversation about battery safety. So I do want to plug battery brunch here. Just last weekend, we had a discussion session on battery safety in EVs. And for the battery brunch coming up in August, on 28th, we're going to be talking about battery safety specifically for electric aviation. And I really like the conversation that we had right now about NMC and NCA and different cathodes and how battery management systems can help, thermal management system can help. I do want to say that the thermal management system has limited effects when you, you know, in controlling the internal temperature of the cell.

1:29:00You know, if you consider a cylindrical cell, the only data that you're getting through the battery management system is the surface temperature of the cell. And for a given surface temperature, you can reach that surface temperature in a variety of ways. You can have a really high internal temperature, if you're charging or discharging at, let's say, 4C. And you can have a very low internal surface temperature that's very close to the surface temperature if you're charging at a low rate, say, 1C. So the battery management system only has the surface temperature data and you will have to be able to predict what the internal temperature of the cell is and the internal temperature is what controls the degradation of the cathode, etc. And we don't really know how the modeling capabilities are going to be able to keep up with the different cathodes and the different use cycles. So those are all interesting questions. And yeah, so if you're more interested in the discussion and on continuing the discussion on battery safety, do join me next month on August 28th.

1:30:19Thanks. No, that's definitely, I can concur that. I mean, these battery brunch sessions are really fun. I've been there probably the last half a year or so. I've been running a few sessions the last time, so I definitely can recommend these. cool. There's also now, if you're in Europe, there's also something called battery pub, which just happened yesterday as well. So that's another version. But if you Google a battery brunch, you will find it, or you can also reach out to Sri Ram and Catherine and myself, we all know about these things. wonderful. Sorry, just another quick addition. I think we were talking about the thermal runway problem that Bassem mentioned as well. There's really very little that we can do once a cell has gone into thermal runway. Like Bassem said, a lot of the internal short circuiting can stem from manufacturing defects. And I think most top tier manufacturers, tier one manufacturers, have internal manufacturing defects at the rate of maybe one in 10 million.

1:31:29That's still a high number, because if you think about having 5,000 to 10,000 cylindrical cells in a vehicle, then you still have the potential for failure in 1,000 vehicles. That's still a high number. And a lot of the manufacturing defects might actually increase in number when you go to things like LSD, because the capacity of each cell is going to increase quite a bit. And the dangers in vehicles such as the Bolt are quite a bit higher because they're in the pouch format. And whenever you see pouch format cells, the failure can cascade from one cell to another very easily. And the cascade failure is actually inherently more difficult when you have cylindrical cells. But of course, we don't know what's going to happen when Tesla goes to the 4680 cells with novel chemistry because you don't have individual modules. When you separate them with modules, then you do avoid the problem of the thermal runaway cascading from one module to the other. But if you have a structural battery pack, it's essentially one full module that's acting as the pack.

1:32:52So there's always the possibility of the entire pack going into thermal runaway very quickly. Of course, they will be conforming to the Chinese standards where you need about five minutes of functional safety before the entire pack goes into full thermal runaway and cascade. But I think some of the inherent dangers are much higher when you do go to the structural battery pack. Thank you, yeah, just looking at the time, I think actually I just want your message as well, maybe it would be nice also to have you in the future session. We're always looking for more conversation starters. We have some great ones coming up, but it would be great to add you as well. We can write about that. Awesome, thanks. And then with this, I'm just looking at the time, time flies as usual, so we're already a bit over one half hours as usual, but I want to first say a really big, big thank you to Basim for giving an excellent conversation style and answering many, many questions.

1:33:58I think it's all very clear, it's very knowledgeable on many of these topics, so very big thank you, big applause. If you know this app, if you've been for a while, you can do some applause by flicking our microphones and and yeah, so that's, you know, you can see a big applause for you, but also one thing, you can also see the fancy flag on his profiles whilst on some other ones. If you're wondering how you can do this, if you put a flag into your profile, then it's going to show up in a profile at least like, you know, next to your icon, at least during Olympia, as far as I know, or the Olympics. Wonderful, and with this, you know, before I give it to Catherine to close today's session, I just want to say we're going to have another session next week called Fit for 50-50, so here we're going to talk a bit about some of these, you know, European policies coming, you know, also related to batteries, but also beyond decarbonization in total.

1:34:52We're going to have probably an interesting discussion also about what does this maybe mean for OEMs and, you know, for like, you know, all the entire car industry with all the suppliers, etc. So I think it's going to be a highly interesting session again, so please join us for this. And then we actually probably have a bit of a one-week break. We might. We're still debating, Catherine and I, if we should do this, maybe one-week break, but then also afterwards, we also have a session coming with James Frith from BNF, so Bloomberg, and we're going to have a fun session. I'm talking about many of these numbers, which also maybe some of them have been mentioned today. And with this, I will pass it on to Catherine to close today's room and session. Oh, Catherine, I'm not sure if we can hear you. Maybe the internet is still a bit of a problematic. Thanks. Thank you so much, Basim, for joining us today. I think we could hear part of it, Catherine.

1:36:14So we heard your thanks for Basim from your side as well. And yeah, maybe, I don't know if the connection is still an issue there, so I can also close it for the two of us for today, and I'm sure next week it's going to be working again. Wonderful. Yeah, then a big thank you for everyone also from Basim, but also everyone on the panel and for sharing their thoughts and their questions and everyone to listen. And if you're interested to listen again, as Catherine mentioned at the beginning, you can find it on batteryinsiders.com or you can also just look for Battery Insiders on Spotify and Apple Podcasts. And maybe just one, you know, one ask from our side as well, if you listened to it on the podcast, and actually I met quite a few people recently who listened to the podcast, so that was really fun. But please also maybe give us a review or some rating because it really helps us for more people to find the podcast and more people to find the sessions.

1:37:05Wonderful. I wish you all a wonderful weekend and see you again next week. Bye-bye.