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March 30, 2022

044 - Improving fire safety of battery systems with Ofodike Ezekoye

044 - Improving fire safety of battery systems with Ofodike Ezekoye

Since Episode 6, the fire safety of battery systems was not very much visible in the show - a good time to change that! And we do this with a  true legend of fire safety - Ofodike Ezekoye. In the last year, I have learnt a lot about battery systems, which did not make me more afraid. Entirely opposite - the more I know, the more confident I am in fire science and engineers finding solutions for any outstanding issues with this emerging technology. In this episode, we go through the challenges at different scales of the battery system - from the chemistry of cathode, anode and electrolyte, through challenges in manufacturing and quality control, battery management systems up to the scale of whole off-grid systems. Each presents unique challenges. Each is a place of ongoing innovation. 

But the most important, IMHO, is to look at the threat holistically. Even if we remove all the intrinsic dangers of energy storage, the batteries may still be there when a fire starts for other reasons... We may be able to contain the 'thermal' threats, but are we looking for solutions to the smoke? And what to do with billions of already existing batteries that we deal with everywhere in our lives... All these questions got answered here, so you don't want to miss this episode!

Transcript

Hello, everybody. Welcome to the Fire Science Show session 44. The legend after legend. I'm pretty blessed with the guests in lineup, in the podcast in the last weeks. And it's not a other today. Enough to say that my today's guests along with, , Professor Babrauskas and Professor Horn alltogether they've published . almost 500. Academic papers. And I find that insane as an academic. Anyway, let's go with the big reveal quickly. My today's guest is professor Ofodike Ezekoye From the University of Texas at Austin. And DK is an expert in battery fire safety. And I cannot imagine a better place working on the fire safety of lithium-ion batteries than. And university of Texas Austin where the thing actually got kind of invented where professor John Goodenough Is lecturing and, yeah, he actually got the Nobel prize for inventing this type of battery. So. Great place to study battery, fire safety and the great research and going in there. I went into this interview with some tough questions about the safety of battery, his thermal runaways and things like that. But in fact, it ended up as quite reassuring talk with a good friend. About what's there to find out how complexity strikes at this. Again. And how smart people are battling for the safety of batteries. I think we've ended up with. Quite well-rounded. Discussion covering. Many many aspects of the battery fire safety. And I can tell you I'm I'm reassured I am a little less scared now. And more optimists. Towards a new solutions that will come for the safety of this technology. And yeah, knowing that the batteries are as a hot topic for the podcast as the wood in fire . I'm absolutely certain, I don't need to hype this anymore and that I already go to your attention and trust me. If you enjoy listening scientists who are absolutely passionate about what they're doing they're happy and enthusiastic about the research and about sharing it with everyone else. This is an episode for you. So I really hope you enjoy. So let's not prolong this anymore. Let's spend in show and jump into the episode. Hello everybody. I'm here today with Professor DK Ezekoye. Hello, DK. Great to have you in the show. Thank you. Welcome. Looking forward to it. I'm even more before the show, you told me that, for the cold chilly Texas, winters, you were thinking about building up some PV installation and batteries. Aren't you scared of that? Absolutely not. I am an advocate of this type of technology of, electrification generally, and certainly in terms of, battery systems. And so, last year, February, uh, we had a winter event here in Austin, which took out our electricity and, took out quite a bit of, infrastructure issues in, in terms of utilities. Even before then, I was very much planning on getting a photo-voltaic, panels and also battery energy storage. And so that obviously just in my mind, it's solidified the need to do this. And for all of us to, in some sense, capability on hand for a renewable energy generation and storage. So I'm very much looking forward to it. And as I said earlier, , my reasons to do what I do are to improve the overall safety of these types of systems. So it's not, , an indictment of the systems. It's not say that the systems themselves are, somehow intrinsically unsafe. It's just that, we need to improve the overall safety of these systems. So more of us can comfortably use them. that sounds like not a bad task you've set for yourself. I find the word safety quite a difficult in this matter, you know, because, I look into Internet, the net people are terrified of the technology. Like literally terrified to the level, uh, where we're banning in many countries, electrical vehicles in the car parks, and, in Poland we had a nice movement where they formated. Mandatory to provide, sufficient electrical power to power, at least a plug-in hybrid, every parking spot in your car park, and this law was put in place. So the buildings are now built with these types of installations, but now the fear has came here now, as we have these installations, we are thinking maybe we should ban the electric vehicles in the car parks. So it's kind of crazy that we've went all the way to invest in this. And now, because of fear, not facts, not science, not proof because of fear. We are rethinking that will not me and the government. Then not I'm in no way connected to them, but, uh, I would despise this connection. Anyway, uh, this safety, you what makes this battery system feel unsafe to people people are not scared of gasoline with heat of combustion of 46 megajoules per kilogram, which you contain like 50 liters on American, it would be like 20 gallons your car. Why we are not scared of riding on this bomb and we're scared of battery. What made us do that? oh, you know, that's a, great question. And. The issue in general, it's the risk perception versus actual risk. And we, in general, as humans are horrible with really understanding risk but risk perception is easy. And so with probably any new technology and especially with the way that we get information these days, that it's very easy to trigger, very irrational fears. And it's in some sense, and maybe I'm guilty of it too, because of just, the fact that we research it might make people think, oh my gosh, these systems are unsafe. Well, everything is unsafe, right? this is part of the issue. There's nothing that is absolutely safe. Well, that's entropy man. Right. Right. So the way, the only way that we can solve some of the really unsafe things, climate change global warming is to use renewable energy and to use energy storage. That is the way that we're going to deal with some of these, incredibly unsafe situations that we should be afraid of and fearful of. And from that perspective, I think that there's a responsibility for technologists who are working in the safety area to be very clear about why the circumstances and issues in which we're looking at safety of particular systems. And again, it's not that these things are, it's not, fear-mongering, it's not that these things are always unsafe and that we should, as a society, stay away from these types of technologies. But in fact, it's that, how do we. incentivize or move forward in terms of these technologies? Because we're improving the overall safety of these systems. And so I'd like to think about the work that I do in the battery area as. Create safer systems, trying to understand these systems better so that we can design against failures because failures to just happen. And we've seen the improvements in safety of, internal combustion engines over the last hundred years. Uh, we could argue that when they were first introduced, I mean, a lot of the safety systems that we take for granted now certainly were not implemented there. So why wouldn't we expect that there would be improvements in safety for whether it's electric vehicles or electric, storage systems within homes, within businesses at utility sites? So the goal of course, is to overall improve safety. And there's just so little data that currently exists. But I think that between the research and unfortunately incidents that occur, we're going to improve the overall safety of these. In fact, if you would look at it at the societal level, I'm obviously not a, not such a researcher. I think you're not either, but you've experienced blackouts last winter. Right. Uh, and, No. Yeah, this type of grid where everyone has a battery, for themselves, that would be probably a life changing experience at that moment. There, the, absolutely. uh, how big the benefit of this technology can be, it Oh yeah, And you, you've mentioned the energy generation and storage, like of the new, new types of fuels we're using, uh, wind solar, they're periodic at best and exactly. if you're nasty to them, Yeah. you yeah. need, you need to way to store that we need to solve that. I also observed this movement that the buildings should be like net zero or possibly positive energy generation. Like would be great if you're building the create more energy than it consumes, that would be the best building and like that exists today. And so it's something we would like. And again, it's something we're afraid of, you know, it's it's, you cannot have both, have to decide. and the more I learn about the systems, the less I am afraid of them. And I think that's probably the correct direction. Well, I guess oh, no, I completely agree. And so, part of it is how do we take industry? How do we take manufacturers from a position of being afraid of even acknowledging that there are safety concerns? To a point of acknowledgement of those safety concerns and with a goal of improvement. And so it's a delicate balance that they have to walk because if on the one hand they talk about safety concerns in their systems, and then it feeds into this perceived risk and perceived safety fears of the general public. Exactly. So that's, so from their perspective, and we've talked to, you know, lots of industrial concerns, about, well, we'd like to help you understand the safety of your battery systems and why battery systems. I mean, from again, the system level, whether to containerize battery system, to whether it's a particular type of appliance and the. Response you typically get is our systems are safe and there are no problems with our system. And as a researcher, who's looking at some of these safety issues. We know that's not true, that they can't possibly always be safe there considerations for I, the one I always think about is listen, fires have happened forever. Fire is always going to happen. Whether we go to space, whether we're on the sea, fire follows us. and so fires will happen. And the issue is that energy storage systems will be somewhere where a fire occurs. It may not be the cause of the fire, but it will be somewhere where a fire occurs, given that what can we do to make sure that your system doesn't add to the consequences of that fire that we know is going to occur? So, and so that's sometimes. Makes them feel a little bit better because it's an awareness that we're not saying that it's their system necessarily, that's the cause of the problem, but that we as researchers and safety science, and in particular on fire issues, we have a wearness about the frequency and intensity consequences of fire generally. And we understand how other fuel packages can get involved in, can exacerbate the fire consequences and fire impacts. So we're trying to help them in some sense, alleviate some of these consequences, some of these negative consequences. So it's a delicate balance then of taking manufacturers and having them acknowledge issues and try and improve the safety of their systems. making sure that the general public understands that the systems are generally safe and this is in fact, the future and providing guidance to regulators and. Permit authorities having jurisdiction, who are decision makers about how to sort of balance this and in their sense of, how do we PR you know, your example, how do we allow EVs in parking garages with the best available safety systems today and what are going to be improvements in safety systems tomorrow, and how do we retrofit or move those forward? That, that sort of, that's a, it's a lot of, it's a lot of work that we have to do for that, huh? Yeah, it seems so it seems like a roadmap to safety is needed or maybe even not to safety. Like it's a roadmap to improve from position A to position B to position C, doesn't mean that position A is unsafe. It's just position B can be safer, right? Yes. be calling it a road to safety that we are unsafe in some way at this point, which may not necessarily be true. For me, a very way. As someone looking around, at this field, which is very alien to me, I'm like, I did a lot of things in, in compartment fires. I've burned buildings. I've did a lot of smoke. but men batteries are alien to me. They are alien. I don't understand them. I know they have power and they serve my laptop. but, I'm not an expert on that. So I wondered We probably need solutions on all levels, but the level of complexity of this thing is really huge. you have the level of chemistry your kathode, anode and I know that the fluid inside, the chemical compounds and reactions that happen inside the battery, have the battery itself as a single cell, element, a single pouch. is an ecosystem on its own with its heat transfer with its with its capacity, right? Then you start merging them together, creating an environment when you've connected multiple of the. Not necessarily, well, you changed the risk. The question is how much do you, did you just add all the risk of them or have you created a system with exponentially higher risk than the cell individually? then again, I've also learned that, don't just put a bunch of them into a car. You need a system that manages them. So need to build a compartment for them or, or some, some case in which they're stalled, which is the technology need the battery management system that makes sure they're operating at the correct parameters that manages the charging and discharging and so on. then you, you have the whole system which would be a car, a building, or the benefactor of the energy of this system. you have this many level of complexities and I see Potential challenges and, also, but then will, opportunities for improving the safety at each of these levels. So please tell me at what level you act and do you think, biggest improvements can come from? Which someone can see, the one you act oh, so, I love what you just said for a lot of reasons. And it goes back to a little bit of what we were saying before. Technology in general and technological systems are getting more complex. So that's something that's absolutely occurring. The pace at which these things are changing and evolving is increasing. The rate is increasing. So we're getting increasing complexity. We're getting increasing complexity faster, and we are on the safety side. We're in some sense, the, boundaries, the, reigns to try to make sure that we manage the overall safety of these incredibly complex systems. And so these battery systems are one of the first, I'm not saying to say that the only, but they're one of the early sort of testing systems for us as safety, technologists, safety, engineers, safety profession, to try to really figure out how do we, allow this transition to occur in a way that makes sense. So. I see myself as really trying to impact the life safety and property protection issues associated with batteries. And the issue though becomes that I feel to do that appropriately inadequately. I need to understand this system because of the complexity that you mentioned, as an academic, I benefit from working with really smart people who can teach me about these systems. So my, sort of goal is to learn about this and to communicate this and to improve the overall safety of these systems. I, we can't do these things alone. We, as we discussed, we work in communities. we tell stories, we talk. And so from that perspective I've asked my students and my collaborators, how to bring me up to speed in terms of our research, by looking at things as sort of. Far from what I do as for example, electrical circuit modeling of cells. So I want to understand fundamentally how does a battery work? And so, uh, I've had students working on, uh, pseudo two D models of cells, of circuit models of cells, of all sorts of different models of cells, so that I can understand the electrical performance of cells and what issues cell researchers are interested in for that, that gives me some insight into what the challenges are at that scale and from a modeling perspective, because that's going to be important as we start to think about multiple cells or as we start to think about even layers of the sort of, uh, single layer cell systems, then at like increasing complexity, then we ask questions about what happens if we have cell failure? How do we think of. Electrical performance as for example, initiating thermal considerations. And so just even in the normal cycling of a cell there's heat generation, and we appreciate that, we know that now the question is can this heat generation itself iManage or is there some possibility of it cascading into a thermal and thermal chemical reaction rate that would occur. And so understanding that is important. And again, I'm not a chemist, but how do we think about parameterizing low order models that can allow us to understand how this reaction process occurs? Again, with an eye at consequence scale at largest largest scales for us, which might be the building or container or the electric vehicle. And so now again, Understanding, for example, cell to cell propagation. Now it's a little bit looking more like what we normally do in terms of heat, transfer, physics, mass transfer issues, solid fire Yeah, exactly. Exactly. So it's looking more like what we do, but it's a parameterization of the kinetics associated with that. I would argue. That's not that different from what we, as fire scientists, researchers have done for decades in terms of looking at condensed phase systems. My gosh, condensed phase, any condensed systems, incredibly complex. I say, Hey, talk about wood or polyurethane or anything. And you tell me that that's simple. That's there's nothing simple about understanding the degradation of these condensed phase systems. now with all the decades and number of researchers, who've put so much energy and intellectual effort into that. We have a better understanding of how these systems degrade and. Both in terms of the toxicity in terms of the energy release rates, in terms of all these factors, what happens with these complex engineered systems, like Polyurethane now, and we've devised tools. You had Vyto Babrauskas on earlier. We've devised tools to characterize and measure the energy release rate of the systems. The, again, the toxicity chemicals, et cetera. We haven't developed that to the same extent for a new technology. Like. a lithium-ion cell, there are tools out there, but maybe we don't understand them or wavy. We haven't fashioned them into a way to really understand some of the issues in terms of propagation. And we're in the early days of characterizing and really understanding those types of details. But arguably once we do understand that and we're able to parameterize these lower order models, then we can think about what propagation looks like. What rate of gas release looks like? What rate of energy release looks like for these types of components. And then we stitch it together at the higher level. Now you said also that the complexity is not just associated with the cells and that's absolutely true. The complexity is that it's a system and it's a software based system, which is increasingly true. So there's a battery management system. There are all sorts of other protection systems often. Some chip or in some sort of logic sequence that's associated with that. And unfortunately bugs can occur. You can buy a BMS for as cheap as $15, and you get what you pay for. So there are really strong battery management systems that no matter how, flawed a particular cell might be, that can overcome the flaws of cell. it and Yeah. Yeah, exactly. They can balance out some of the issues between poorly performing cells and better performing cells because natural variability exists in terms of sort of cells from a manufacturing perspective or otherwise. And then on top of it, we may have other components in the system, whether it's an inverter or other sort of traditional electrical mechanical systems, any of these can possibly fail on top of it because of failures, we have sensors. And so the sensors could initiate some sort of activity. one would say that, oh, that would be crazy for a sensor system to initiate. an intervention that might cause additional failures, but I think we've seen that even in the battery space where, oh, misdiagnosis of say smoke, the smoke could have been outside of the battery container. So a smoke detector could trigger intervention, for example, a water spray that could damage the cells and then lead to a cascading propagation. And so without again, naming names, things like this have occurred. So, as we think about these very complex systems, maybe B issue really is that we have to rethink how we, analyze safety for very complex systems. And maybe we're really learning with these battery systems. And this is the template by which our profession evolves in terms of understanding safety. I'm not even sort of, I know nothing about fusion, but every week there's another article that, yeah. that there are improvements and pathways towards workable fusion reactors. Somebody's got to protect. So we already protect nuclear reactors as a community. So the new, the nuclear industry uses fire and safety professionals to ensure that these incredibly complex systems don't catastrophic fail. we're going to have increasingly spaceports and we're going to have rocket systems and all the complexity associated with the fuels there. And we're going to be the ones asked to manage them. we think about the, there was a recently a large warehouse fire in the U S warehouses aren't supposed to burn, right. We, you know, we have all sorts of fire protection systems in place that should protect against them, but it's with the increasing complexity of all these systems that, you know, maybe we sort of, the piecemeal approaches to protection and the research associated with thinking about protection for these complex systems that it has to evolve also. And I know that you're doing a lot of work in terms of characterization of complex systems. And you know, whether it's, again, did, you said building scales buildings are increasingly complex systems with software controls, HVAC system sensor systems. It's insane. Yeah. It's incredible. Isn't it? Yeah. It's, I'm very safe about my war job with this complexity increase. I wanted also, going back to this, issue of fear and, safety, A failure is a failure. Not every failure is a catastrophe. I wondered if maybe we could try characterize what distinguishes a failure that could be acceptable or, negligent. From a failure that, turns into, first page of a newspaper, we've seen these videos. Uh, there was a video in the Shanghai with a huge fire. was a video of Chinese buses catching fire. there was a, this ship that burned down plenty of fancy cars for Americans, which you will not get. It's a shame when that's right. you, are going to ride Okay. now, Those aren't safe either. You know, you can get kicked by a horse. I would claim it's also rich people vehicle and that's, but yeah, What's the scenario when this fire of a battery system becomes catastrophical, what is the cause of such a fire? I know a phrase thermal runaway, and, it sounds scary. And, uh, I guess the videos have shown that, but how does, uh, a failure of a cell become a catastrophe good. Okay. So maybe first of all, we talk about possible failures of cells. And so, um, a cell itself could fail because of challenges in manufacturing. what's interesting is that, my university, university of Texas, uh, A long history of sort of excellence in, battery materials. And so we have distinguished, we have a Nobel Laureate with distinguished researchers who were working on the battery materials issues. there's a big step up between sort of designing and envisioning what the right battery materials are and the actual manufacturing of batteries. And so a couple of years ago, few years ago, we decided that we were going to embark on, an exercise to develop a battery fabrication of prototyping facility. And, I was fortunate enough be involved and I'm still involved in that process. And so, what I've learned about that is, is that battery manufacturing is A) really hard, there is limited metrology and in some sense, quality control there. The us government has finally realized that battery manufacturing is a strategically important national interest. So it's something that absolutely needs to be done because we're increasingly relying on these types of technologies. So learning about that has pointed out to me that very small mistakes can occur in terms of the manufacturing that would perhaps not immediately recognize in any kind of cell testing, but could have long term consequences when a cell is supposed to last years, for example, so thousands of cycles. well, I think when we're, when we were talking about battery manufacturing, I don't know if everyone realizes it, but we were talking about quantities manufactured at the same time, all. a line of battery produces like hundreds Oh, the few seconds oh, absolutely. quicker than, uh, machine gun in terms of Oh, it's So, here it's not a quality control where you would take every cell and put it into a on, say, oh, this cell is okay. No, we're talking about it's a printing press. Literally it it's a, it is a printing. It looks like a printing press. There's roll to roll technology. You're absolutely right. Everybody should watch, go to YouTube and take a look at a battery manufacturing facility in terms of how it's operating. So And so with manufacturing them, I can imagine even a small issues at random. Like every yes, you get the one that goes wrong, but yes, five minutes. Right. yes, no, no. You're you're so you're, you're hitting the exact points. Is that. Defects can happen when you're producing these types of large numbers and even with really good quality control, some things will slip by that may have a problem. Okay. Now, a particular cell might have that type of defect in it. otherwise a cell, could go into failure because of what we talked about before the battery management system. So one of the things that the battery management system is trying to do is it's trying to balance, for example, between all the different cells, in a battery. So again, when we talk about a battery, a battery is comprised of cells and these are individual cells and these cells can be as small as, a milli amp hour or so a hundred million amp hour or so, or as large as a hundred amp power. So, which, you know, we we've looked at and tested. . From that perspective, there's a scale range in terms of the energy storage associated with a given cell. a large cell failing has very different consequences from a small cell failing. And now the battery management system is trying to balance between the different cells and whether it's in parallel or series configurations. And, there is the possibility for example, that because the cells are not identical, that you might over time overcharge over discharge, any particular cell in the string of cells that comprise the battery and that could lead to failures. And those failures could be, for example, something like an overcharge that might occur. And so in terms of the overcharge that might be occurring, for lithium ion cells, you can get plating of the lithium metal because it's a transport issue, such a tray. So transport limitations of the ability of intercalated. Lithium ions into these active materials could cause something like a plating process to occur as this lithium played in this lithium metal occurring. For example, on the anode side, then you would get the possibility of dendrites forming. And these are again, just whiskers. If you think about them like that metal whiskers that could penetrate across the separator, which is trying to keep the, the electrical charges away from each other, if you will, from certain having sort of spontaneous discharge and then that could lead to a short circuit. so operationally one could get a failure to occur in terms of manufacturing. One could imagine that there's a failure that occurs and certainly in terms of mechanical damage, whether it's a belt bending process, Crash of a vehicle that causes a mechanical failure and, that bending, for example, puts elements the anode closer to the cathode or tears, the separator, or punctures, the separator. And then you can have a short that's formed because of this mechanical failure process. and then of course there's environmental failure. So we, again talk about the fact that fires occur. We know the fires occur, so, a high temperature environment could lead to the degradation of whether it's the separator, within the particular cell or two, reactions occurring, with. The, cell itself, and those could lead to this sort of cascading failure of all these different reactions. And that's the process that we talk about in terms of thermal runaway. So a single cell failure will occur. Single cells will fail from any number of reasons. And as you say, The issue becomes what is management of single cell failure look like? , and there are design professionals who are increasingly tasked to understand how to manage single cell failures, either through a heat transfer mechanisms. so, what kind of flows would we direct around a single cell or around the arrangement of cells? So that if a single cell failure occurred, it doesn't cascade. , in terms of compartmentalization, as you mentioned. So are there whether it's facing materials or other types of materials that one could layer into the systems to manage the heat transfer? Now that management heat transfer is complex because as we said before, just normal cycling of a cell causes the cell to heat up. So there is you think of it as a diode on under certain conditions, under normal operating conditions. I'm going to get heat out of the cell. and manage the overall system in terms of that heat transfer under abnormal operation conditions for a single cell, I may want to isolate that cell, so I will let that cell burn away, but I don't want it to cascade to the other cells. So, people and organizations are designing, developing, I should say design tools and it's not just CFD. It could be resistance network. It could be other types of tools that would now be increasingly used to design the safety systems and protection systems. Oftentimes we think about it really as a thermal protection systems for batteries. Okay. So batteries, single cells can fail. There are design professionals, whether it's an electric vehicle company or at a, an integrator developing for, onsite protection at a utility or at a big box, Uh, retail outlet, et cetera. these protection systems. Now having said that hopefully those protection systems are still able to manage single or two or three cell failures. I would say that there's a push there had been a push to going to larger cell capacities because of economies of scale and for all sorts of good reasons, , for electric vehicles. So people were saying, okay, well, let's go with, 94 amp hour cells or larger capacity cells. Those are harder to manage both thermally and otherwise in terms of failure. So in some sense, we know there are vehicle companies, a lot of them came out of Silicon valley that leverage what happened. Laptops and portable electronics that have much smaller capacity cells. and so these are whether it's 18650, 2170. So there are the smaller cell capacities and different formats that other companies have said, well, you know what? We can manage and control these better. Now there challenges in terms of, you know, having so many small cells. So there's probably some happy medium that, EV. .companies and others are going to think about in terms of, dense enough and high enough energy density and large enough cells, but not too large, that it becomes a control issue later on. Okay. So landscape wise, there has to be this idea then that there is some sweet spot in terms of size of cells that can be controlled so that if and when a failure occurs, it can be managed. So it doesn't cascade and propagate. Now I'm interested in that, but again, I say, well, if they don't do their job perfectly in quotes, um, we're still going to get larger scale propagation. And when we get larger scale propagation, we can get a whole module that fails. What are the impacts of that? Now it's kind of interesting. So, , probably you say the same thing. When I teach my fire science class, one of the first things we talk about is that the thing that sort of kills people most in fires is not the heat and fire. It's a smoke. So, I think that in some sense, we overthink the thermal issues associated with battery failures and under think. Toxicological impacts of it or the cascade of battery failures to other fuel packets. And then to really the thing that we're afraid of, or I'm afraid of, which is the smoke. So I think that connecting the dots between, okay, cell failure, what gases are released, what are the issues in terms of toxicity? How would this impede people in terms of egress or otherwise, what are the secondary fuel packages that could be involved in this failure? How do we understand that cascade? What are the ignition issues and how do we think about what the life safety implications of that might be? That's I think that's where I want to be clear and really sort of hammer on it and, and. that's that's a strong one, man. That's that's a good one. You're right. that's probably the biggest challenge I had when I started playing with, electric vehicle fires and trying to answer the doubts of people related about the car parks and electric fires goes. I, when I'm talking about, traditional fires, if you can call um, that you have this, let's say rule of thumb, tenability criteria, uh, visibility of 10 meters is let's say acceptable. You know, what amount of suit that, is, you know, the soot yield of your source. can figure that out. You can find the plausible answer, if I want to do, electrical fire, One thing that I noticed is they will have a completely different, uh, heat release rate curve and correct me if I wrong, but it looks like not, exponential is like logarithmic is like very, very sharp. It's not a huge release and suddenly dresses by, by a factor of 10 or 20. That, that's what I saw, from the measurements. And that's what you see in videos when there's like nothing, nothing, nothing, and the huge flame. Uh, so we figured that out. And we can in a way account for that by, making a very quick, uh, heat release rate, in our simulations, if we traditionally gave four minutes of fire growth to reach a one and a half megawatts of a car simulate a car fire in the car park, traditionally, as we did in past on TNO experimental results from many years ago, for electric vehicle, okay, let's start the simulation with one megawatt initially. Like goes from zero to one megawatt immediately. course I'm making an error. Of course I'm far away a reality, but who in fire science is not. so, but yeah, but then that's a way to solve it. Yeah. But then again, emissions, like do I account what's my. What's my, I didn't, I can't even call it a soot yiel what's my smoke yield. yeah, I think that's important. And, and, how bad is that? Am I still Yes. 10 meters visibility or, will I be very dead seeing for these 10 meters at this point? that so frightening because I, I don't even have a good idea how to make it up. Like it did with the you know, I love that. Work. That's been, the RISE folks have done in terms of the battery space and vehicle fire space. So when the shipboard fire just a curve, one of the things I wanted to talk to about to my class about was, um, well, let's look at the heat release rate from an ICE versus a, , battery electric vehicle. And when we looked at the data sets and I said, okay, let's here. I'm showing you the heat release rates. they were all between say five and seven megawatt peaks. And I said, okay, tell me which one you're more concerned about. And we looked at it and we looked at it and we looked at it and we thought, yeah, they look a hell of a lot of like, you know, it's very difficult to discern sort of the one that I'd be more afraid of. And so when you think about all the fuel involved in a vehicle, um, lot of stuff. That's not necessarily battery and there's lot of stuff to be afraid of that has nothing to do with the battery. So now the question in my mind then becomes, okay. And I like to think about it this way. , we all know that smoke is bad. Smoke is bad when fires occur, but are some smoke situation worse. So are there things that are being produced toxicity wise than might be worse because there is a battery involved and here's the thing. I don't know what the answer to that question is, but I'd like to know. And that's what I'd like to put effort into and it's, it impacts obviously, occupants, but it really dramatically also impacts the fire service because when they're fighting these fires, they are intimately involved. So while yes, but they're on S CBAs. They're on air. Yes they are. But when you go. less than a hundred meters away, you see all sorts of firefighters congregating around equipment and otherwise without air packs on what's happening to them. , are there issues in terms of the, over the, is there change? I don't, I'm not saying there is, is there a change in the overall toxicity of the smoke because of the amount of batteries that have been involved in it? In the U S we just saw an incident, we've seen a few incidents now, and we've seen it around the world where, there have been, evacuation orders that have been placed when fires that included large amounts of lithium-ion batteries were occurred. And all those required is it really just, is it essentially a regular. Or is there something much worse or different about those, plumes that we need to think about? So, there's so many different aspects of this, and again, we're not trying to say that no batteries intrinsically and just are such a bad technology and we should not be going in this direction, but it's a clarification. So we understand better when they can be used, how they can be used and how to improve it. And just talk about, just, you know, I'm rambling. I'm sorry, it's this that's the point of a podcast. yeah. We're, we're at a pub and, um, I'm drinking my coffee and just given an opportunity, ramble. Um, but you, you think about something you think about something else that I, I think that, there has been a lot of fear about which is a flame retardant chemistries. Okay. So flame retardant. have been, you know, in quotes, thrown under the bus as, and some of your guests on this podcast hate flame retards. I'm not going to name any names. but they say that they don't really do anything. And for the, the harm that they potentially have, that it's not worth putting them in place. Now, if you look at a airplane, I don't think anybody in terms of safety systems for planes in terms of, you know, the seats and et cetera, we'll say, oh, let's take out the flame retardant because we know that time is critical in those situations. And it's incredibly important. And then arguably, because of the complexity of flame tardy chemistries, they have gotten much, much better over the last 30, 40 years. It's enormous improvements in terms of their overall safety. So. Has research been important here in terms of identifying the potential issues and problems with it? Absolutely. I say, has the industry responded by making safer flame retardants? Absolutely. So I think that the same issue has to happen in terms of why we look at batteries that maybe the first few sort of ways that people put together, battery protection systems really inadequate, but something had to be done. And it's incumbent on researchers to understand what the limitations and issues associated with. The safety of these systems are point them out and allow industry and other organizations to respond, to require and improve the overall safety of these systems. So I think, I think that there were analogies and there are ways that we're going to move along this. Yeah, on them. What you said, that's the one thing that scares me, the longevity of this technology that, even if we figure out, if you go tomorrow and figure out your noble price, awards the technology to make batteries fireproof or something, Yeah. just going to be the new batteries while we have already millions of electric vehicles on the roads old batteries, you know, and from my perspective, people come to me and ask, we design a car parks for electric vehicles from now? And I tell them years ago, when you designed the car park, you designed it for electric vehicles. He just didn't know. and that's not the choice we make. so, have to deal uh, with this in a smart way, not only with the newly produced, well maybe if you're a manufacturer, you probably are responsible for what you're on the fracture, but us as a safety engineers, delivering safety to the we're also responsible about what's around and how to manage that. And I really wonder if there are ways we, manage that or do we just have to hope this, things replaced themselves. However, I also read somewhere lately that, the rates of fires in electric vehicles were remarkably low, uh, that there was some insurers claim. don't know if how much truth is in that, but it was very, if that is true, that would be very, very nice. Maybe you have some knowledge about the statistics of, vehicle battery fires in general. oh gosh, I wish I did. , uh, you know, every paper we write about that we, point to, other people's papers and it all sort of leads to one paper essentially about what failure rates look like. Uh, but like you said, I think insurers are increasingly getting information. I mean, we're just as the population and number of electric vehicles has come up. They seem to be much safer than, internal combustion engine vehicles in terms of fires. I mean, I think that's becoming quite clear that they are less prone to fires than, internal combustion engine vehicles. And so now it's like, okay, we're on the right path. And that's a good thing. There's something else that you said there was really, I thought it was really interesting. It's just, you everybody and their grandmother is looking at, what's the next battery technology. And so whenever I talked to, protection type companies, I said, well, what about solid state batteries? Aren't those supposed to get rid of sort of the safety problems associated? And I said, listen, we're increasingly getting higher energy density and higher power density in all these battery systems. When failure occurs and the failure does not have to be associated with the cell itself because of all the reasons that you and I've just talked about. If there's a fire and your battery is involved with it, how does it contribute or impact that fire evolution? So that's question number one. Okay. Even with solid state batteries, there are so many problems right now with all safety. I just read something recently about, there's an electric vehicle company. They said we have solid state batteries in our vehicle. The range is no different. In fact, it's less range than, uh, liquid solvent-based, electrolyte, batteries. And it still has the sort of standard electrolyte materials in it because the solid state electric. It's brittle it cracks. There are all sorts of problems with it. So it's really a mixture of the sort of conventional electrolytes and the solid state electrolyte, if you will. And so, there's probably a decade before really this just real implementation in this. When I talked to, the battery manufacturing people, and even then, as you said, the conventional batteries are commodity and are relatively inexpensive, and those will dominate in a lot of markets and in a lot of applications. So in some sense, we're going to be challenged with managing safety systems for new and evolving battery systems, as well as the old systems where, these large companies have dumped billions of dollars into manufacturing capability for these conventional systems. So we just have to keep working. Yes. but after this talk, I'm fascinated because now I see that, though the cell may be an old technology, it a new compartment, giving it a new battery management system, giving it, access to some new, uh, safety features, like active systems that, that could, uh, react it, it Yeah, improve their safety, despite it being, another technology from, uh, from ancient times, like 2013. Right. So. that's right. That's it? That is your spot on ancient times. Indeed. Yeah. And, and w one more thing. also mentioned this smoke, as a problem. And I often run into this issue discussing the problem with people. like, man, these fires are huge. their temperature is insane. Like, okay, that's, that's always nice. That's great. they, they will like destroy the concrete building. They burn so ferocious and they can burn for two days and I'm like, holy shit. That's like a, that's a noble price because you broke conservation of energy and mass, like, uh, so it's, either. And my experience with people who test the batteries is like, if it burns quickly and fiercefully, that's actually okay, because That's a good thing. that's, that's the best thing that's going to happen in the Oh, did gosh, you're saying you're so hot. It's funny. We just had a conversation with our local fire department. They were talking about electric vehicle fire and say, Hey, what you know is this really true? We need to apply in quotes, copious amounts of water. I said, Hey, you know what? I think, again, vehicle company X said this, and I really agree with it. if there's not an exposure that you're worrying about. Let the damn thing burn and let it burn quickly, let it burn quickly so that you don't have to babysit it forever so that you do get rid of all the stuff. stay in it. Yeah, that's true. That's right. You got it. You got it's exposures and those exposures, not just thermal exposures, it's thermal and emissions exposures, but it's really, it's managing exposures, but the way we might think about it as the safest batteries, a burnt battery. So if we can burn it, we're good. We no longer have a problem, you know, Hey, which I'm not even gonna speak to the fact that is one of the challenges. Is that when an electric vehicle or one of these appliances burn, there are a lot of cells in there dead. Go off. It's your point too? You said that she said, okay, if five cells go off, isn't that safe? Well, it's safe for somebody, but it might be safe, unsafe for somebody else who has to get those five cells out or manage that battery. Now that several cells have failed in it and others are compromised. So we don't know how compromised the other cells are. And that becomes a longer-term issue. But that's, there's going to be a whole industry that comes up to deal and manage with those issues. burns batteries is very difficult. Uh, Yeah. tell you how we do it, but I can just say that I would just, I can just say that, that having, having, uh, you know, fire resistance furnaces a lot in some things like, I like it. yeah. like it. I agree with you. I agree with you. when we, when you do this battery tests, like the rule is Yeah. leave them there for a week. And, uh, after a week there's, they're more or less, it would be very awkward if Uh, happened the week after and on the exact day, when you chose to pick it up, I would act, I would then consider it an act of God and I would just live with it. So that's, that's, the point of view, but, it should that, burns batteries, safer battery yeah, the unburned one. absolutely. discussed this with respondent, Yes. They need to know. There are two kinds of threads. They will be exposed to one being a huge fire to which they are used to word. The challenge Okay. toxicology because the fire will be there as they know it. It's just gonna to be a little different chemical composition of the smoke in which Yes, yes, anyway. yes, exactly. that's option a and option B if something weird is happening, it's, it's puffing, it's, Yes. smoking his gun that that's a completely different scenario. And then maybe I can imagine where you would have to isolate this vehicle or this battery, even four days. yeah. And let's say option C. And so, whether it's confined or unconfined becomes the issue. And so, we go to the surprise arson incident and other incidents. It's just that, I conventionally have dealt with non pre-mixed flames. I deal with, you know, natural burning systems. but in another life I did work on premixed lengths. And so the, the challenges becomes that explosions can occur. I mean, so we're not just, we're not just, so when does this thing becomes under ventilated, if it's confined, it's becomes under ventilated. The products are not just CEO that we might see in normal, under ventilated combustion systems. We had hydrogen and we have hydrocarbons in there. And so the explosion hazard is real. And so we have to start thinking about explosion protection in a serious way for our confined or partially confined battery systems. I know the last one we did blew up. Yes, yes, yes. Nah, but wow man. it's an hour already. I told you like Yeah. presentations are boring and long, but when I write, oh, this is great. like, it's good. So quickly. This is great. Any famous last words? This was a lot of fun. uh, no, but seriously, let's, let's close it up with some statements. So I think I share your mindsets. I'm not scared of this technology. It's a new technology, relatively new, we're on the front of making it safer, which does not mean it's unsafe and there's lots of smart people working on it and, trying to, make it better. Right. hopeful. I am. I'm very hopeful. I think that you, you summed it up perfectly. we're moving into, there's nothing we can do to change this trajectory. I don't think because it's incredibly required and, we're just trying to improve it. That's all. So I'm, I'm very hopeful that all of the effort that you and others and, we're all trying to collectively do in this space. we'll create safer systems. Yeah, man. Thanks. This was, this was excellent. I thought she was going to be excellent. He didn't believe that Ah, this is I really enjoyed it. It was a great pleasure having you in the fire sane show and I'm sure I'm going to see you here again, I hope to I hope so you in Austin as well. Uh, that would be wonderful. That would be wonderful. th there's supposedly some pickle challenge, posed was the better way to eat a pickle like Polish way, super sour or Texas way fried. So we were going to settle that in the battle. And it should be, it should be an Austin. We'll we'll do it in Austin. We'll do in Warsaw. We'll do it all over. Thank you so much. thanks. Absolutely. Thank you for doing this. See you around Take care. Goodbye. And that's it. Hope you've liked this. I've spent one hour talking to DK and he's my best friend now. It was an amazing episode. So enthusiastic, so happy about. The research he's doing and so optimistic towards the future. And I think that's what I really needed. And optimistic view towards the fire. See future of lithium-ion battery technology. Because it is a part of our future. Whether we like it or not. And, and it's great that smart people are working. To make this technology as safe as possible. And as we mentioned in the episode, It does not mean it's not safe. It means we are still seeking solutions, how to tackle problems better, how to identify problems better. How to apply solutions at many layers of the protection within the battery. And with all this. Just make it. Better more accessible. . Easier to replace, easier fire risk perspective. So I hope you've enjoyed this optimistic view on batteries. And you can share this with all of your friends who are. A little scared of the technology. And maybe they will give a little more enthusiastic about it. And with this optimistic. accent I would love to close this episode. Thank you so much for being here and listening. And I hope to see you next week. Another great interview coming your way next Wednesday. Cheers. Bye.