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thanks. this reminds me how expensive or terribly inefficient cylindrical cells is in space and thermals. while it was good enough years ago, EV makers definitely need to move on to LFP cells. additionally, EV makers should look into none-conductive mineral oils for battery thermal management-the coolant lines feels cringey in terms of expense and complexity to me.
I'm a chemical engineer and did a considerable amount of heat transfer design in the chemical process industry. I'm pretty sure the Lucid cooling plate, which looks like a dimple jacket on a vessel, operates in the turbulent regime (with a Reynolds Number over 4000), not laminar flow with a Reynolds Number under 2100. Turbulent flow increase the heat transfer coefficient at the boundary layer of fluid and the metal surface and therefore improves heat transfer during cooling and heating.
Yeah, that threw me for a loop as well. the dimples look like they would induce turbulent flow to create a uniform heat distribution in the fluid, but is it possible that the flow remains laminar past the dimples and they are placed to pick extract heat uniformly even though the flow is not turbulent? naively I’d guess turbulent flow would be the best way to extract heat, but I’m not familiar with this field
Thanks, Tom, for the interesting presentation. Several points: 1) it's worth noting for context that steady-state heat dissipation required for a battery pack is only about 1% of the average power level, perhaps around 200 - 300 watts while driving, of trivial concern compared to that when DC charging. 2) Several EVs use cooling panels on the outside of the pack in order (I believe) to enhance safety in the event of loss of coolant containment, those models being all Hyundai/Kia E-GMP, gen-2 Kona/Niro and VW iD. In the case of Hyundai/Kia this change coincided with a move away from using a 'low-conductivity' blue coolant which has proven to be problematic in terms of cost and reliability for owners. 3) The Ioniq 5 cooling panel (you were discussing) I'm fairly certain has a composite panel placed underneath for insulation and/or physical protection. 4) The solid/liquid cooling phases v.s temperature change you've eloquently described is exactly why the ongoing loss of summer Arctic sea ice poses such a problem for the containment of northern-hemisphere jet streams and therefore weather.
Thermal performance for driving and outright acceleration is important but I would submit that driving ~300 miles in about 4 hours typical means a discharge rate of 0.25C while charging a 75 kWh pack at 250kW is about 3.3C and so should generate MUCH more heat than discharging. So the thermal design robust enough for fast charging should prove more than enough for any kind of driving.
But, that is not the only use case for EVs. Some people, like OOS Kyle, drive them very hard on tracks or suitable roads. Surely, there is significant heat generation during high current discharge.
True that charging generates a lot more heat in the battery than normal driving. However, when racing the heat generated in the battery often overcomes the ability to cool the cells. At the Pikes Peak Hillclimb the Tesla Model 3 Performance and Model S Plaid reach max battery temperature, reducing the max available power.
@@georgepelton5645 The hill climb or at a track is about the only way you can require a lot of power from the battery long enough to make it overheat. On road with a 0-60 of about 3 seconds, you would far exceed any speed limit before the battery and drivetrain could get hot. I'm talking about normal hiway driving.
Perfect. Few people understand that charging is much more aggressive for battery than normal using. Even 30kw warms a lot, more than a normal urban driving
Fantastic rundown Tom, thank you for all the detail! In the 90's I worked for a test laboratory that measured the heat flow through window and door products, to determine their u-value (thermal conductance, or the inverse of r-vlaue) of each product for labeling. The end result was Btu's per square foot, per hour, per degree temperature difference, or BTu's/Ft2/Hr/Delta T. Your presentation brought back lots of memories and meant a lot to me! Thermal management of EV battery packs is no small task under the wide variety of both external conditions and driving conditions!!
Your explanation of the three types of heat transfer opened my eyes. I knew what they were but had a hard time defining how they were different from each other. Boiling (no pun intended) it down to how they are physically attached makes so much sense. One is physically connected, one is connected by a fluid, and the third is not connected by anything. 💡
The Caveat is that it's all just Radiation. The nuance is what that radiation is interacting with. The convection fluid is just mechanically removing the radiation that imparted energy into the molecules of the fluid.
really excellent discussion! I liked that you were able to mix in basic explanations of phenomena while still diving deeper and using precise terminology where appropriate. I’m not an aspiring engineer but I have to imagine that it’s immensely valuable to anyone who is to have a chance to hear the lingo and use it as a jumping off point for deeper study.
For a bit different kind of battery cooling, in the formula student team I was on, we cooled the battery with only phase change material. As the only times we are using it is either small quick runs or the endurance witch is in the order of the 2000 seconds of run time, so we could just heat soak the whole run and find that to be lighter than air or water cooling
Good timing and well done. I experienced a shutdown of charging at a Supercharger today, 95+ degrees. Car said to unplug and retry, no joy. The battery was replaced recently and developed a coolant leak from a broken fitting. They repaired, but the coolant pumps have been very active.
Great presentation! I would expect Lucid to have their cooling technology nailed due to their experience in Formula E. Sure would be cool to see a Formula E battery!
Thank you. It is interesting to note that the methods used by different manufacturers are all different. Clearly, everyone was doing the best they could to heat/cool their batteries. And thank you for mentioning the benefits of using the latent heat of fusion and latent heat of vaporization for temperature control. Good to see that we don't forget the basic thermodynamic properties of materials and apply them advantageously to achieve the requirements.
The issue with bottom cooling is the much smaller surface area. I've seen a detailed study, which concluded that side cooling is better. Turns out the steel casing of the cell conducts the heat from the bottom to the sides very efficiently. Another issue with Lucid's solution is that there's less protection against thermal runaway. Cooling pipes are pretty good at stopping fire.
Makes sense. When you think about the fluid dynamics of the heat its radiating outward through the sides. Who can remember high current vacuum tubes and Darlington Transistors that had big side mounted fin heatsinks to get that heat away. What's interesting about the peak heat and package thermal expansion is it is only during max charge and discharge cycles right? Run at 1C its not too bad - bump it to 6C and its rises dramatically.
Thank you and looking forward to more EE explanations. The biggest takeway I see is that T never commisioned Munro for an audit. The issue I see with the biggest EV supplier it that it cheaps out on innovation but it also does the same on experience. You should NEVER cheap out on experience. Sure, you can relearn the lessons, buy cheap but thrice, but, cars are a safety critical thing. Having worked with German automotive, the conservative alternative is almost as bad. I understand the lean design of T but it comes at the expense of paying customers, either financially or physically.
Fantastic summary for all us people that wanted to know the comparisons between all the manufacturers! Thanks for your vey clear and succinct description!
Fascinating presentation, Tom. It's really interesting to see how the different cell types influence cooling choices and how the cooling techniques have evolved over the last few years.
Thanks, Nice presentation which can be followed by regular people without much technical background. For those who know more than regular people would love to hear more about other design considerations, such as flow type (laminar/turbulent), liquid speed per channel, cooling efficiency (heat power/ pump power) corrosion erosion robustness, reliability, etc.
The cooling flow is interesting. Obviously some cells get better cooling than others when the flow is sequential. This was the primary issue for eventual failure of the original Prius battery pack. The prismatic packs at the outer ends lasted longer than the middle cells in the stack because the middle cells ran several degrees hotter. The packs still operated for more than double the warranteed life but if your removed those failures the pack lasted over a decade. And the first manifestation of error was imbalance.
Thanks a lot for your teardowns. These presentations are very important in laying bare EV technology for both users and the maintenance and support industry.
Thermal management of the battery cells is even more important when it comes to cooling while quick charging as well as preheating, and also when you like to maximize the lifespan of the cells.
This is a good breakdown of pack cooling for vehicles already in production, but you left out the immersive cooling scheme that Sandy looked at with Faraday 3 years ago. Using a dielectric fluid, possibly the same quasi-ATF Tesla uses to cool its motors, eliminates all the internal plumbing of cooling tubes and cold plates in favor of a continuous spray of fluid over the cells and suction to pump it back out through external heat exchangers. So a greatly simplified pack design at the expense of slightly more expensive coolant. You also didn't mention any scheme for a reserve bottle of coolant independently warmed or chilled that can be switched into place when sudden performance cooling or pre-conditioning is needed.
Excellent! Everything is is presented in detail and depth. Tom not only understands the minutiae, but how it all comes together, and the practical physical considerations to be considered. Best of all, everything is accurate! Well, almost... @ 3:20 he mentions the "vacuum of space" which as any Quantum Mechanic knows is actually crammed full of "Black Matter", which continuously pours out of Worm Holes which in turn get them from the bottom side of the Flat Earth. 🤪 As for efficient thermal coupling under all use cases, the flat, serpentine cylindrical, radius cooling channel is demonstrably the best, with pouch and prismatic not so much. Heat Pipes are primarily for space constrained uses and are not very efficient, unless you put a pump in them, in which case it's just another form of refrigeration (and huge, expensive and power hungry). Fun Fact: the smallest cell shown is the one made by Panasonic (in Japan and Nevada) and is quite likely to be in your Laptop PC. Laptop PCs are where you'll also find most heat pipes deployed as well.
I had to fix the pack on a 2018 Volt and it definitely had cold plates full of antifreeze between every couple batts. It has supe stable temperature but it does look somewhat expensive.
I wonder if it were possible to combine a battery array and a cooling system with a thermoelectric array to convert the heat produced into additional charge to lengthen the power longevity. Or would the thermoelectric array not generate enough charge to be of benefit and could affect the efficiency of the cooling system?
I am conducting research on heat dissipation through gas-liquid phase change, but directly immersing the battery in a boilable fluorinated liquid presents issues such as sealing and chemical compatibility. Therefore, I opted for a design similar to a heat pipe. The shape of the evaporation end of the heat pipe is conformally designed to perfectly fit the surface of the battery, increasing the heat dissipation area. The condensation end can utilize various cooling methods. Additionally, I proposed a 'Jelly Roll to Pack' design, where the Jelly Roll is directly inserted into the cavity of the battery pack.
I'd love a cooling concept for LMC cells. Especially the green one from ford you showed us at the beggining. I hope to rebuild a plug in cmax ernergi pack with newer higher AH cells of the same dimensions and I'd love to see if it's possible to build in a liquid cooling approach to prolong the battery life but realize there is not a lot of room to work with those packs.
Two things worth mentioning about the Hyundai cooling strategy: they're using an 800 Volt system and they're not trying to put up Tesla or Lucid levels of acceleration/power,. Since resistive heating goes as current squared times resistance, cutting your current needs in half (which using a higher voltage system will do) should reduce your cooling needs by a factor of 4. In short, Hyundai can likely use a less aggressive cooling solution because they're just not generating as much heat.
@@ryen7512 Nope. Cell voltage doesn't matter: current matters. The cells are in series so they see the same current. The PACK is at 800V allowing the same power as a 400V system but using 1/2 the current. All cells will see 1/2 the current as a 400V system and, therefore should produce less heat.
@@indeedgrasshopper your confusing pack voltage with cell voltage. All lithium ion cells are about 3.7 volts nominal. So they all produce the same current for a given total power output. For example when the user accelerates at 100 Kw on a 400v pack vs 800v pack, the cells all see the same current draw, thus produce the same heat (this is also assuming the total pack sizes are the same.
Cooling systems is Cool😊, I have a question, other day I needed to charge My Tesla Model Y for just for 40-50 miles range, Outside temp was about 85 F, When I plugged in for supercharger, battery needed to heat before it could charge to higher charging rate, Does Tesla’s battery staying too cool inside the battery pack !as it is surrounded by foam even in summer heat ?, May be it’s good for longevity of battery pack but for a supercharging purpose it would be helpful if battery is not too cold, also I have noticed in winter, charging at home 32 kw via Mobile chargers doesn’t warm battery. Any thoughtful answer will be appreciated.
I find it really interesting that the ionic 5 has such thick thermal the conductive material but they have some of the best thermal management of an electric car
Tom ,Thank You for your thermal cooling/ heating knowledge base transfer to me. You really did warm up my brain when flowing along to be later cooled down by sweating through the insight detailed here as in depth understanding concisely presented here in this video in much appreciated detail. Thank You again, Tom, for the gift of knowledge given so freely for just an effortless "like" click. An insightful video to watch was after repeat review created ! Thank You Sandy for paying for Tom to present to us wishing to soak up the knowledge with understanding so artfully presented by Tom. Nice !
As a Previous owner of a Tesla model 3 2018 to the new owner of a Honda Prolouge 2024 ( a chevy blazer EV with a honda badge) There is a huge difference between some things ive noticed. When the Model 3 got home to charge after a long road trip there was virtually no heat given off the car to make my garage warmer. But this new Honda on the Ultium platform 2024 Made my garage so hot after a long road trip while charging that the dry wall that covers my garage attic celling opening was lifted up and moved out of the way to let all the heat that came out of the car by itself just from the heat. Any insight on this? Is the Newer Honda able to expel heat better than the Tesla or is all this heat a sign of bad efficiency? Id love to hear your guys opinion on this Because it seems like the heat from the Honda comes from where your traditional radiator is on an Ice car and puts out a ton of very hot air if i pop the hood and feel the air. But the Tesla made almost zero noise and gave off nearly no heat. Thanks , Great Video guys.
@@Miata822 Possibly, im pretty sure the tesla dryer plug is equivalent to the honda one i hard wired as they both required the same breaker.I know there is more to it to that but maximum energy output is controlled by the breaker.
@@DerpMcDerp101 Max output is actually controlled by the EVSE, the thing plugged in to that socket. The EVSE sends a signal to the car saying how much it can deliver and the car won't draw more than that. The socket and breaker should be sized 20% higher than the EVSE's max capacity. A "30A" dryer plug is good for a 25A EVSE. My car came with a 40A EVSE so I put in a 50A socket and breaker. Munro actually has a video talking about using the right sockets since many appliance type sockets aren't really engineered to deliver their rated power for hours on end as happens when charging an EV. Sorry for the long sidetrack but getting this stuff wrong can have serious consequences.
@@Miata822 The Dryer socket i got came directly from Tesla and i trust them whole heartedly to make the best plug made for the job . Un fortunately i do not feel the same way about the GM brand. Thats just a gut thing thing from past experience. And what i meant about the breaker is that you cant get blood from a turnip its only capable of supplying and amount of power that can not exceed the breakers capability. And i know that since they have the same breaker requirement for both that they are somewhere near each other its not like im charging this new honda at break neck speeds or anything compared to the tesla. I feel as if maybe the Tesla was just better at getting rid of the heat while its driving which is why my garage didn't get 1000 degrees when i got home after a long road trip. Unlike the Honda was blowing out an enormous amount of heat when i got it home, But im not entirley sure.
I have a feeling your suspicions are correct. Tesla is much more efficient than other manufacturers. It could be that the Model 3 doesn't generate as much heat as the Honda.
heatpipes are good to cool CPUs because the range of conditions is pretty small ( like 50-150W ) so it's relatively easy to have a vapor chamber that uses phase change well in that range and conduct heat away from the source very effectively. In something the size of a car battery with all the different loads and exterior factors from freezing temps to 45°C+ outside, not sure about that one...
Thanks for the presentation! In addition to heating during acceleration, battery life can be impacted by heating during charging. Believe the failure mode is lithium plating at the anode during charging---especially supercharging.
Having studied and used heat transfer analysis, there is going to be larger temperature gradients with flat plate cooling (top or bottom). I’d expect the Tesla serpentine cooled batteries to significantly exceed the life of flat plate cooled batteries. My guess is legacy auto manufacturers are writing procurement specs consistent with ice vehicles, not in line with the potential life of an EV.
Looks to me like you would have greater thermal disparity within the battery the longer the coolant lines are, How much mechanical and temperature stress is that disparity causing and how much difference is causing due to local overheating due to coolant temperature and individual differences between discrete cells? You would need a certain maximum temp for the hottest cell in the battery during max electrical output or charging rate.
Fantastic presentation- thanks Tom! Does serviceability of packs and cells ever enter the design consideration? I can’t imagine what it would be like trying to pry one or two cells out of any of those packs if they went bad. The literature on my MiniCooper SE refers to a modular design to aid in service but I would doubt they mean right down to the cell level that you could pop out like the battery in your tv remote.
1. IONIQ5 N's cooling management is very good. Why? It proved the Pikes Peak hill clim. It reached the summit without any power loss due to heat, unlike the Tesla. Isn’t that the complete opposite of what he said? 2. Munro's cool(ing) Concept is a very dangerouse. If a car equipped with the battery gets hit in a side impact, at that moment, the battery turns into a massive bomb. Or imagine if there’s just one faulty cell in there.
Good job, very informative. Note you skipped over free vs forced convection heat transfer because little heat transfer in EVs is 'free'. BTW is that your Seebee fuselage back there..? 🙂👍
Genuinely always questioned why use liquid for heat transfer instead of gas. I feel you were starting to touch on this towards the end. Couldn't you use a heat pump refrigerant cycle to achieve greater results and less weight?
Good Thermals on 4680 structural battery pack, but no axis for repair of any kind, including BMS modules. I Don't need >$15k of disposable battery. "Our cells are lasting longer and longer" you say. Well loss of just one BMS is at least 25% battery degradation. If the pack still worked at all.
Question? What causes CELL failure? Overheating, Lack Of Cooling, or is it a Temperature difference? Is the Coolant pressurized when it's in the coolant loop or channel? Has Munro and associates ever used Thermocouples regarding the temperatures of the cells, or a infrared test? What's the Failure mode of the cold plates?
1. Cell intrnal defect. Just statistics, one in a million has a defect and shorts. 2.Coolant is not pressurized except in the beginning of the loop due to flow resistance (pressure drop). But this is in range of 1bar. Last question : common one is insulation failure. It is hard to insulate stuf electrically and yet more a cold plate which has a million holes for venting. Snake is easier to coat reliably but can still fail if you have a pinhole or a metalic particle which damages the coating. Cheers
If a piece of thermal conductive solid material (eg a piece of aluminum) was oriented vertically and heat applied mid vertical height, does heat in a solid rise like heat in a liquid?
Does the Ioniq 5 N use different cooling than the normal Ioniq 5? Or did the new model 3 performance change its cooling? I’ve been watching videos of it doing multiple Nurburgring laps without any heat issues, with regenerative braking on. But the new model 3 performance has to turn off regen because of battery temps. But then it can’t do multiple laps because the brakes over heat.
What did the sapphire run at the green hell? Rawlinson sure seems to be laboring under the impression lucid is ahead of tesla. But he could just be lucid dreaming. 👍🏻😀
Well of all the Manufacturers. Only Lucid has the experience with Battery used in extreme condition due to their Formula E experience. They know how to cool those batteries.
Thank you for sharing various battery cooling approach. I don't agree your view about Hyundai pouch cell cooling. As it was demonstrated at Pipe Peak International Hill Climb by Hyundai 5N, the battery was cooled well and there was no power limitation through the rally. According to Randy Pobst who drove Plaid last year and holding the best record as EV, Ioniq 5 could hold 100% power for the whole run but Plaid need to manage the battery temperature by derating the power. The hill climb time of Ioniq 5N TA was shorter than Plaid TA and broke the record of EV. It is impressive when we compare the power of the vehicles. Ioniq 5N is slightly tuned for this race as 677 HP by software while the power of Plaid is over 1000HP. I think the difference was achieved by battery cooling efficiency and cell performance of the pouch design. Since the pouch cell is flat and shallow, the heat dissipation is much easier than the cylindrical cell. Also, the path of electron transfer is much shorter than cylindrical cell which decrease the heat generation by internal resistance. In the race, the outright winner was Ford F-150 lightening Supertruck with 1600HP which is far different from the production model. Interestingly, both EV from Hyundai and Ford are applying pouch cell from SK ON. Especially Ioniq 5N is using same cell as EV9, Ioniq 5 Face lift, EV6 face lift and ST1 which is truck model. The cell from SK ON can be charged within 18 min from 20% to 80% which had the shortest charging time in the production EV models.
How about making a true structural "honeycomb" with cooling passages almost completely surrounding each cylinder, plus one-end cooling. Electrically isolate the cells within the cylinders, and have terminal connections at the same end for all cells. It would be possible to pressure and structurally test the honeycomb before cell insertion, and with some imagination many cooling paths are possible, as well as future cell replacement. The same concept would work for biaxially-symmetric prismatic cell assemblies (maybe solid-state cells). We'll never get to reasonable weight EVs until we start building proper structural battery packs, and since the necessary machining and welding technology is already available, why dally?
The 7 to 8 minute lap time at Nürburgring is another performance threshold. The Ioniq N seems to be able to have enough cooling capabilities for 2 laps. Then it goes in to charge. The new Taycan has cooling worth investigating. Cooling and heating is important for DC fast charging.
your mock up ignores the cte of plastic to the steel cans. They will fret and warp the pack hot to cold ambient. You are not controlling the pack temp during off times of course.
Maybe I missed it, but how come the LUCID system cools the end of the battery? Everybody else decided they have to use a serpentine cooling system which cools the sides of the batteries. Thanks in advancej.
BMW uses end cooling as well. The inside of cylindrical cells contain thin strips of metal, the anode and cathode, that are rolled up tightly and stuffed into the cell housing The anode (or strips of metal attached to the anode) make physical contact with the bottom of the cell housing. This provides a shorter path for heat to follow. With side cooling the heat follows a longer path and internal parts of the cell may be at very different temperatures. Recall that Tom mention that thermal conductivity depends on both the material and the distance travelled. Lucid developed this system for the Formula E racing series..
If a cell manufacturer was also made responsible for designing and building the pack I wonder if they would still use round cells over pouch or prismatic given the added complication of designing a pack? To me the round cell concept is much like one engineering group taking the easiest approach for themselves without any consideration of the overall application. Using serpentine cooling strips seems like a nightmare design for high volume production, nevermind safely connecting all those small cells together. And filling the pack with unpredictable expanding foam is a terrible idea in a production environment. One small change I've noticed in one of Hyundai/Kia newer battery pack designs is to using larger pouch cells to eliminate having 3 in parallel, now 96 cells in total instead of 294. Cell balancing is improved because 2 cells can't support a lagging third. And repairability of packs must become a required feature eventually.
Could the battery be flooded in oil? Truly, I would not mind slower supercharging and lower acceleration for a lower cost. I expect to supercharge my car very few times per year.
I have an electric dirtbike (Caofen FX) with an oil cooled 72v60ah battery. its enclosed in an aluminum alloy case and filled with what appears to be mineral oil and also has a built in battery heater that supposedly works in 40 below zero. I almost want to open the thing up to see what's inside. I think this method of cooling would be cost effective and simpler.
You could maybe say that they short in the sense that they create a shorter electrical pathway, but then they're electrically connected anyway; that's what makes them parallel.
Great stuff, Tom! I have been waiting for Munro & assoc. to mention thermodynamics. I have questions about Tesla's choice of side cooling the 4680. That cell is ideal for end cooling yet we see side cooling every second row on the structural pack. It seems obvious that there will be a large temperature gradient within each cell as the side away from the cooling channel has a much longer heat path that for instance in Tesla's 2170 and 18650 packs. This cooling scheme seems to greatly reduce any thermal advantage from the anode and cathode end tabs. Does the rigid support material foamed into the structural pack have particularly high thermal conductivity?
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thanks. this reminds me how expensive or terribly inefficient cylindrical cells is in space and thermals. while it was good enough years ago, EV makers definitely need to move on to LFP cells. additionally, EV makers should look into none-conductive mineral oils for battery thermal management-the coolant lines feels cringey in terms of expense and complexity to me.
I enjoyed that advertisment. Can't say that for many ads.
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Mandarin.
Speaking of. When will do a BYD teardown? Would love to see one.
This is the level of technical detail that got me hooked on this channel. Nice to see it again 👍
Glad to hear it!
I'm a chemical engineer and did a considerable amount of heat transfer design in the chemical process industry. I'm pretty sure the Lucid cooling plate, which looks like a dimple jacket on a vessel, operates in the turbulent regime (with a Reynolds Number over 4000), not laminar flow with a Reynolds Number under 2100. Turbulent flow increase the heat transfer coefficient at the boundary layer of fluid and the metal surface and therefore improves heat transfer during cooling and heating.
Mach-E cooling plates are dimpled for turbulence also.
Even if laminar flow, these dimples mimics the mixing effect of turbulent flow that helps increase heat transfer
Lucid declared in one of their tech talks that they designed for turbulent flow.
I think he just meant that it would transit the maze uniformly without hotspots.
Yeah, that threw me for a loop as well. the dimples look like they would induce turbulent flow to create a uniform heat distribution in the fluid, but is it possible that the flow remains laminar past the dimples and they are placed to pick extract heat uniformly even though the flow is not turbulent?
naively I’d guess turbulent flow would be the best way to extract heat, but I’m not familiar with this field
Great presentation - love seeing all the differences between brands and over the years.
Thanks for watching!
Thanks, Tom, for the interesting presentation. Several points: 1) it's worth noting for context that steady-state heat dissipation required for a battery pack is only about 1% of the average power level, perhaps around 200 - 300 watts while driving, of trivial concern compared to that when DC charging. 2) Several EVs use cooling panels on the outside of the pack in order (I believe) to enhance safety in the event of loss of coolant containment, those models being all Hyundai/Kia E-GMP, gen-2 Kona/Niro and VW iD. In the case of Hyundai/Kia this change coincided with a move away from using a 'low-conductivity' blue coolant which has proven to be problematic in terms of cost and reliability for owners. 3) The Ioniq 5 cooling panel (you were discussing) I'm fairly certain has a composite panel placed underneath for insulation and/or physical protection. 4) The solid/liquid cooling phases v.s temperature change you've eloquently described is exactly why the ongoing loss of summer Arctic sea ice poses such a problem for the containment of northern-hemisphere jet streams and therefore weather.
Tell us about the red Taurus in the background as well!
@@dogownrpennaI'm more interested in knowing what that other "vehicle" next to the Taurus is. Looks like a boat. What is that?
Thermal performance for driving and outright acceleration is important but I would submit that driving ~300 miles in about 4 hours typical means a discharge rate of 0.25C while charging a 75 kWh pack at 250kW is about 3.3C and so should generate MUCH more heat than discharging. So the thermal design robust enough for fast charging should prove more than enough for any kind of driving.
Absolutely
But, that is not the only use case for EVs. Some people, like OOS Kyle, drive them very hard on tracks or suitable roads. Surely, there is significant heat generation during high current discharge.
True that charging generates a lot more heat in the battery than normal driving. However, when racing the heat generated in the battery often overcomes the ability to cool the cells. At the Pikes Peak Hillclimb the Tesla Model 3 Performance and Model S Plaid reach max battery temperature, reducing the max available power.
@@georgepelton5645 The hill climb or at a track is about the only way you can require a lot of power from the battery long enough to make it overheat. On road with a 0-60 of about 3 seconds, you would far exceed any speed limit before the battery and drivetrain could get hot. I'm talking about normal hiway driving.
Perfect. Few people understand that charging is much more aggressive for battery than normal using. Even 30kw warms a lot, more than a normal urban driving
Thorough AF... Thanks. I loved the comparson across time & manuifacturers.
Fantastic rundown Tom, thank you for all the detail! In the 90's I worked for a test laboratory that measured the heat flow through window and door products, to determine their u-value (thermal conductance, or the inverse of r-vlaue) of each product for labeling. The end result was Btu's per square foot, per hour, per degree temperature difference, or BTu's/Ft2/Hr/Delta T. Your presentation brought back lots of memories and meant a lot to me! Thermal management of EV battery packs is no small task under the wide variety of both external conditions and driving conditions!!
You know your stuff & present it really well. Thank you.
Thanks for watching
Your explanation of the three types of heat transfer opened my eyes. I knew what they were but had a hard time defining how they were different from each other. Boiling (no pun intended) it down to how they are physically attached makes so much sense. One is physically connected, one is connected by a fluid, and the third is not connected by anything. 💡
The Caveat is that it's all just Radiation. The nuance is what that radiation is interacting with. The convection fluid is just mechanically removing the radiation that imparted energy into the molecules of the fluid.
really excellent discussion! I liked that you were able to mix in basic explanations of phenomena while still diving deeper and using precise terminology where appropriate. I’m not an aspiring engineer but I have to imagine that it’s immensely valuable to anyone who is to have a chance to hear the lingo and use it as a jumping off point for deeper study.
For a bit different kind of battery cooling, in the formula student team I was on, we cooled the battery with only phase change material.
As the only times we are using it is either small quick runs or the endurance witch is in the order of the 2000 seconds of run time, so we could just heat soak the whole run and find that to be lighter than air or water cooling
Good timing and well done. I experienced a shutdown of charging at a Supercharger today, 95+ degrees. Car said to unplug and retry, no joy. The battery was replaced recently and developed a coolant leak from a broken fitting. They repaired, but the coolant pumps have been very active.
Great presentation! I would expect Lucid to have their cooling technology nailed due to their experience in Formula E. Sure would be cool to see a Formula E battery!
Thank you. It is interesting to note that the methods used by different manufacturers are all different. Clearly, everyone was doing the best they could to heat/cool their batteries. And thank you for mentioning the benefits of using the latent heat of fusion and latent heat of vaporization for temperature control. Good to see that we don't forget the basic thermodynamic properties of materials and apply them advantageously to achieve the requirements.
Good post. Most liquid cooled EVs today can use a change of state (refrigerant from the HVAC system) to cool the coolant sent to the battery pack.
The issue with bottom cooling is the much smaller surface area.
I've seen a detailed study, which concluded that side cooling is better. Turns out the steel casing of the cell conducts the heat from the bottom to the sides very efficiently.
Another issue with Lucid's solution is that there's less protection against thermal runaway. Cooling pipes are pretty good at stopping fire.
Makes sense. When you think about the fluid dynamics of the heat its radiating outward through the sides. Who can remember high current vacuum tubes and Darlington Transistors that had big side mounted fin heatsinks to get that heat away. What's interesting about the peak heat and package thermal expansion is it is only during max charge and discharge cycles right? Run at 1C its not too bad - bump it to 6C and its rises dramatically.
This was an incredibly informative and well done video. Thanks Tom and the Munro team!
Thank you and looking forward to more EE explanations. The biggest takeway I see is that T never commisioned Munro for an audit. The issue I see with the biggest EV supplier it that it cheaps out on innovation but it also does the same on experience. You should NEVER cheap out on experience. Sure, you can relearn the lessons, buy cheap but thrice, but, cars are a safety critical thing. Having worked with German automotive, the conservative alternative is almost as bad. I understand the lean design of T but it comes at the expense of paying customers, either financially or physically.
Fantastic summary for all us people that wanted to know the comparisons between all the manufacturers! Thanks for your vey clear and succinct description!
This was a wonderful presentation and well presented.
Great comparative deep dive and excellent demo of what Munro is all about!
Thanks
Fascinating presentation, Tom. It's really interesting to see how the different cell types influence cooling choices and how the cooling techniques have evolved over the last few years.
Very informative vid.
My compliments.
Many thanks!
Thanks, Nice presentation which can be followed by regular people without much technical background.
For those who know more than regular people would love to hear more about other design considerations, such as flow type (laminar/turbulent), liquid speed per channel, cooling efficiency (heat power/ pump power) corrosion erosion robustness, reliability, etc.
Including entering & leaving fluid temperature, and temperature of the battery cells at different locations...
The cooling flow is interesting. Obviously some cells get better cooling than others when the flow is sequential. This was the primary issue for eventual failure of the original Prius battery pack. The prismatic packs at the outer ends lasted longer than the middle cells in the stack because the middle cells ran several degrees hotter. The packs still operated for more than double the warranteed life but if your removed those failures the pack lasted over a decade. And the first manifestation of error was imbalance.
I'm sure he'd be wasting his talents doing it, but Tom would make for a great teacher!
That was a great introduction into batterry cooling. Thank you.
Glad you liked it
Thanks a lot for your teardowns.
These presentations are very important in laying bare EV technology for both users and the maintenance and support industry.
Excellent summary of battery cooling methods. A mention to Faraday's immersion cooling would be nice.
Always enjoy your analysis professor👍!!!
Thanks Tom. Wow! Truly a comprehensive breakdown of BEV batteries, Fascinating. ❤❤❤
Cool, we finally got to learn more about computation fluid dynamics~
Thermal management of the battery cells is even more important when it comes to cooling while quick charging as well as preheating, and also when you like to maximize the lifespan of the cells.
Great info as always! Keep up the amazing work/content Sandy & team! You’ve got some serious Superstars there! ⚡️😎
Thanks so much!!
Excellent conversation
Impressive presentation.
Thank you so much for the detailed data!
Our pleasure!
This is a good breakdown of pack cooling for vehicles already in production, but you left out the immersive cooling scheme that Sandy looked at with Faraday 3 years ago. Using a dielectric fluid, possibly the same quasi-ATF Tesla uses to cool its motors, eliminates all the internal plumbing of cooling tubes and cold plates in favor of a continuous spray of fluid over the cells and suction to pump it back out through external heat exchangers. So a greatly simplified pack design at the expense of slightly more expensive coolant. You also didn't mention any scheme for a reserve bottle of coolant independently warmed or chilled that can be switched into place when sudden performance cooling or pre-conditioning is needed.
Excellent! Everything is is presented in detail and depth. Tom not only understands the minutiae, but how it all comes together, and the practical physical considerations to be considered. Best of all, everything is accurate! Well, almost... @ 3:20 he mentions the "vacuum of space" which as any Quantum Mechanic knows is actually crammed full of "Black Matter", which continuously pours out of Worm Holes which in turn get them from the bottom side of the Flat Earth. 🤪
As for efficient thermal coupling under all use cases, the flat, serpentine cylindrical, radius cooling channel is demonstrably the best, with pouch and prismatic not so much. Heat Pipes are primarily for space constrained uses and are not very efficient, unless you put a pump in them, in which case it's just another form of refrigeration (and huge, expensive and power hungry).
Fun Fact: the smallest cell shown is the one made by Panasonic (in Japan and Nevada) and is quite likely to be in your Laptop PC. Laptop PCs are where you'll also find most heat pipes deployed as well.
Thanks for video!
My pleasure!
Loving this series. Cheers.
Thanks!
I like this guy.. I watch at 2x speed and he's still a smooth
I had to fix the pack on a 2018 Volt and it definitely had cold plates full of antifreeze between every couple batts. It has supe stable temperature but it does look somewhat expensive.
I wonder if it were possible to combine a battery array and a cooling system with a thermoelectric array to convert the heat produced into additional charge to lengthen the power longevity.
Or would the thermoelectric array not generate enough charge to be of benefit and could affect the efficiency of the cooling system?
I always like Peltier cooling but that may be hard to scale to whole battery pack?
Likely too costly and too heavy to justify a small added amount of electricity.
Wow. This is next level deep.
Thank you.
Fascinating! Thank you.
Glad you enjoyed it!
Nicely done. Great explanation and overview of the differing cooling tactics.
I am conducting research on heat dissipation through gas-liquid phase change, but directly immersing the battery in a boilable fluorinated liquid presents issues such as sealing and chemical compatibility. Therefore, I opted for a design similar to a heat pipe. The shape of the evaporation end of the heat pipe is conformally designed to perfectly fit the surface of the battery, increasing the heat dissipation area. The condensation end can utilize various cooling methods. Additionally, I proposed a 'Jelly Roll to Pack' design, where the Jelly Roll is directly inserted into the cavity of the battery pack.
Very interesting discussion. Thanks!
I'd love a cooling concept for LMC cells. Especially the green one from ford you showed us at the beggining. I hope to rebuild a plug in cmax ernergi pack with newer higher AH cells of the same dimensions and I'd love to see if it's possible to build in a liquid cooling approach to prolong the battery life but realize there is not a lot of room to work with those packs.
I guess that was demonstrated on the module side of your concept at the end.
Two things worth mentioning about the Hyundai cooling strategy: they're using an 800 Volt system and they're not trying to put up Tesla or Lucid levels of acceleration/power,. Since resistive heating goes as current squared times resistance, cutting your current needs in half (which using a higher voltage system will do) should reduce your cooling needs by a factor of 4. In short, Hyundai can likely use a less aggressive cooling solution because they're just not generating as much heat.
The ➗ 4 only applies for the cables.
the cells are all the same voltage so they all produce the same heat.
@@ryen7512 Nope. Cell voltage doesn't matter: current matters. The cells are in series so they see the same current. The PACK is at 800V allowing the same power as a 400V system but using 1/2 the current. All cells will see 1/2 the current as a 400V system and, therefore should produce less heat.
@@ralanham76 Why is that? Chemical inefficiencies? I'm not a battery engineer (mechanical) but it should be less at the very least.
@@indeedgrasshopper your confusing pack voltage with cell voltage. All lithium ion cells are about 3.7 volts nominal. So they all produce the same current for a given total power output. For example when the user accelerates at 100 Kw on a 400v pack vs 800v pack, the cells all see the same current draw, thus produce the same heat (this is also assuming the total pack sizes are the same.
Cooling systems is Cool😊, I have a question, other day I needed to charge My Tesla Model Y for just for 40-50 miles range, Outside temp was about 85 F, When I plugged in for supercharger, battery needed to heat before it could charge to higher charging rate, Does Tesla’s battery staying too cool inside the battery pack !as it is surrounded by foam even in summer heat ?, May be it’s good for longevity of battery pack but for a supercharging purpose it would be helpful if battery is not too cold, also I have noticed in winter, charging at home 32 kw via Mobile chargers doesn’t warm battery. Any thoughtful answer will be appreciated.
I find it really interesting that the ionic 5 has such thick thermal the conductive material but they have some of the best thermal management of an electric car
Great video on a confusing subject. Thx
Tom ,Thank You for your thermal cooling/ heating knowledge base transfer to me. You really did warm up my brain when flowing along to be later cooled down by sweating through the insight detailed here as in depth understanding concisely presented here in this video in much appreciated detail. Thank You again, Tom, for the gift of knowledge given so freely for just an effortless "like" click. An insightful video to watch was after repeat review created ! Thank You Sandy for paying for Tom to present to us wishing to soak up the knowledge with understanding so artfully presented by Tom. Nice !
What is the weight of the pack casing, the batteries and the water piping for the various systems? A couple of examples?
As a Previous owner of a Tesla model 3 2018 to the new owner of a Honda Prolouge 2024 ( a chevy blazer EV with a honda badge) There is a huge difference between some things ive noticed. When the Model 3 got home to charge after a long road trip there was virtually no heat given off the car to make my garage warmer. But this new Honda on the Ultium platform 2024 Made my garage so hot after a long road trip while charging that the dry wall that covers my garage attic celling opening was lifted up and moved out of the way to let all the heat that came out of the car by itself just from the heat. Any insight on this? Is the Newer Honda able to expel heat better than the Tesla or is all this heat a sign of bad efficiency? Id love to hear your guys opinion on this Because it seems like the heat from the Honda comes from where your traditional radiator is on an Ice car and puts out a ton of very hot air if i pop the hood and feel the air. But the Tesla made almost zero noise and gave off nearly no heat. Thanks , Great Video guys.
That could be influenced by your charging speed.
@@Miata822 Possibly, im pretty sure the tesla dryer plug is equivalent to the honda one i hard wired as they both required the same breaker.I know there is more to it to that but maximum energy output is controlled by the breaker.
@@DerpMcDerp101 Max output is actually controlled by the EVSE, the thing plugged in to that socket. The EVSE sends a signal to the car saying how much it can deliver and the car won't draw more than that. The socket and breaker should be sized 20% higher than the EVSE's max capacity. A "30A" dryer plug is good for a 25A EVSE. My car came with a 40A EVSE so I put in a 50A socket and breaker.
Munro actually has a video talking about using the right sockets since many appliance type sockets aren't really engineered to deliver their rated power for hours on end as happens when charging an EV. Sorry for the long sidetrack but getting this stuff wrong can have serious consequences.
@@Miata822 The Dryer socket i got came directly from Tesla and i trust them whole heartedly to make the best plug made for the job . Un fortunately i do not feel the same way about the GM brand. Thats just a gut thing thing from past experience. And what i meant about the breaker is that you cant get blood from a turnip its only capable of supplying and amount of power that can not exceed the breakers capability. And i know that since they have the same breaker requirement for both that they are somewhere near each other its not like im charging this new honda at break neck speeds or anything compared to the tesla. I feel as if maybe the Tesla was just better at getting rid of the heat while its driving which is why my garage didn't get 1000 degrees when i got home after a long road trip. Unlike the Honda was blowing out an enormous amount of heat when i got it home, But im not entirley sure.
I have a feeling your suspicions are correct. Tesla is much more efficient than other manufacturers. It could be that the Model 3 doesn't generate as much heat as the Honda.
heatpipes are good to cool CPUs because the range of conditions is pretty small ( like 50-150W ) so it's relatively easy to have a vapor chamber that uses phase change well in that range and conduct heat away from the source very effectively.
In something the size of a car battery with all the different loads and exterior factors from freezing temps to 45°C+ outside, not sure about that one...
Considering that 1) heat rises, 2) Bottom of the pack is exposed to impact, why are the cold plates installed at the bottom of the cells?
Thanks for the presentation! In addition to heating during acceleration, battery life can be impacted by heating during charging. Believe the failure mode is lithium plating at the anode during charging---especially supercharging.
when over discharged and in cold conditions. yes.
Having studied and used heat transfer analysis, there is going to be larger temperature gradients with flat plate cooling (top or bottom). I’d expect the Tesla serpentine cooled batteries to significantly exceed the life of flat plate cooled batteries. My guess is legacy auto manufacturers are writing procurement specs consistent with ice vehicles, not in line with the potential life of an EV.
Looks to me like you would have greater thermal disparity within the battery the longer the coolant lines are, How much mechanical and temperature stress is that disparity causing and how much difference is causing due to local overheating due to coolant temperature and individual differences between discrete cells? You would need a certain maximum temp for the hottest cell in the battery during max electrical output or charging rate.
😄Good day from GOONELLABAH, NSW!🌏 Tom's article on battery cooling is very instructive. Thank you. I am a structural engineer.
🤗Cheers, Ian Cleland
Fantastic presentation- thanks Tom! Does serviceability of packs and cells ever enter the design consideration? I can’t imagine what it would be like trying to pry one or two cells out of any of those packs if they went bad. The literature on my MiniCooper SE refers to a modular design to aid in service but I would doubt they mean right down to the cell level that you could pop out like the battery in your tv remote.
Amazing video, thanks for this type of content
Can you guys do a formula E race car tear down or similar. Must be some cool stuff in there
Probably not
@@MunroLive maybe you could ask for an older or even a crashed one? Formula e is just about to switch over to the awd gen 3.5 beta car.
When will we see more of the Munro 4680 concept?
1. IONIQ5 N's cooling management is very good. Why? It proved the Pikes Peak hill clim. It reached the summit without any power loss due to heat, unlike the Tesla. Isn’t that the complete opposite of what he said?
2. Munro's cool(ing) Concept is a very dangerouse. If a car equipped with the battery gets hit in a side impact, at that moment, the battery turns into a massive bomb. Or imagine if there’s just one faulty cell in there.
Thank you for a great presentation
Good job, very informative. Note you skipped over free vs forced convection heat transfer because little heat transfer in EVs is 'free'. BTW is that your Seebee fuselage back there..?
🙂👍
Genuinely always questioned why use liquid for heat transfer instead of gas. I feel you were starting to touch on this towards the end.
Couldn't you use a heat pump refrigerant cycle to achieve greater results and less weight?
Good Thermals on 4680 structural battery pack, but no axis for repair of any kind, including BMS modules. I Don't need >$15k of disposable battery. "Our cells are lasting longer and longer" you say. Well loss of just one BMS is at least 25% battery degradation. If the pack still worked at all.
Why not just periodically reverse the flow? seems like that would be a much simpler method.
Your phase transition idea sounds cool but what about heating a pack? Seems it only works for cooling.
Fascinating. Thanks.
Excellent
Thanks
Is cooling more important during DC fast charging or a high performance/ fast discharge situation?
Question?
What causes CELL failure?
Overheating, Lack Of Cooling, or is it a Temperature difference?
Is the Coolant pressurized when it's in the coolant loop or channel?
Has Munro and associates ever used Thermocouples regarding the temperatures of the cells, or a infrared test?
What's the Failure mode of the cold plates?
1. Cell intrnal defect. Just statistics, one in a million has a defect and shorts. 2.Coolant is not pressurized except in the beginning of the loop due to flow resistance (pressure drop). But this is in range of 1bar. Last question : common one is insulation failure. It is hard to insulate stuf electrically and yet more a cold plate which has a million holes for venting. Snake is easier to coat reliably but can still fail if you have a pinhole or a metalic particle which damages the coating. Cheers
If a piece of thermal conductive solid material (eg a piece of aluminum) was oriented vertically and heat applied mid vertical height, does heat in a solid rise like heat in a liquid?
Does the Ioniq 5 N use different cooling than the normal Ioniq 5? Or did the new model 3 performance change its cooling? I’ve been watching videos of it doing multiple Nurburgring laps without any heat issues, with regenerative braking on. But the new model 3 performance has to turn off regen because of battery temps. But then it can’t do multiple laps because the brakes over heat.
Thank you!
You're welcome!
I'm curious. At what size battery would side and bottom cooling be needed ?
If Sapphire battery cooling is so good, why was it not able to beat the plaid time at Nürburgring?
What did the sapphire run at the green hell? Rawlinson sure seems to be laboring under the impression lucid is ahead of tesla.
But he could just be lucid dreaming. 👍🏻😀
Well of all the Manufacturers. Only Lucid has the experience with Battery used in extreme condition due to their Formula E experience. They know how to cool those batteries.
Thank you for sharing various battery cooling approach.
I don't agree your view about Hyundai pouch cell cooling.
As it was demonstrated at Pipe Peak International Hill Climb by Hyundai 5N, the battery was cooled well and there was no power limitation through the rally.
According to Randy Pobst who drove Plaid last year and holding the best record as EV, Ioniq 5 could hold 100% power for the whole run but Plaid need to manage the battery temperature by derating the power. The hill climb time of Ioniq 5N TA was shorter than Plaid TA and broke the record of EV. It is impressive when we compare the power of the vehicles. Ioniq 5N is slightly tuned for this race as 677 HP by software while the power of Plaid is over 1000HP.
I think the difference was achieved by battery cooling efficiency and cell performance of the pouch design. Since the pouch cell is flat and shallow, the heat dissipation is much easier than the cylindrical cell. Also, the path of electron transfer is much shorter than cylindrical cell which decrease the heat generation by internal resistance.
In the race, the outright winner was Ford F-150 lightening Supertruck with 1600HP which is far different from the production model.
Interestingly, both EV from Hyundai and Ford are applying pouch cell from SK ON.
Especially Ioniq 5N is using same cell as EV9, Ioniq 5 Face lift, EV6 face lift and ST1 which is truck model. The cell from SK ON can be charged within 18 min from 20% to 80% which had the shortest charging time in the production EV models.
What about running ac in the batterie cooling plate?
How much heat is made during normal driving?
Good job. 👍
Thanks 👍
How about making a true structural "honeycomb" with cooling passages almost completely surrounding each cylinder, plus one-end cooling. Electrically isolate the cells within the cylinders, and have terminal connections at the same end for all cells. It would be possible to pressure and structurally test the honeycomb before cell insertion, and with some imagination many cooling paths are possible, as well as future cell replacement. The same concept would work for biaxially-symmetric prismatic cell assemblies (maybe solid-state cells). We'll never get to reasonable weight EVs until we start building proper structural battery packs, and since the necessary machining and welding technology is already available, why dally?
The 7 to 8 minute lap time at Nürburgring is another performance threshold. The Ioniq N seems to be able to have enough cooling capabilities for 2 laps. Then it goes in to charge. The new Taycan has cooling worth investigating. Cooling and heating is important for DC fast charging.
@26:30 you want turbulent flow not laminar for extraction of heat
your mock up ignores the cte of plastic to the steel cans. They will fret and warp the pack hot to cold ambient. You are not controlling the pack temp during off times of course.
Maybe I missed it, but how come the LUCID system cools the end of the battery? Everybody else decided they have to use a serpentine cooling system which cools the sides of the batteries. Thanks in advancej.
BMW uses end cooling as well. The inside of cylindrical cells contain thin strips of metal, the anode and cathode, that are rolled up tightly and stuffed into the cell housing The anode (or strips of metal attached to the anode) make physical contact with the bottom of the cell housing. This provides a shorter path for heat to follow. With side cooling the heat follows a longer path and internal parts of the cell may be at very different temperatures. Recall that Tom mention that thermal conductivity depends on both the material and the distance travelled. Lucid developed this system for the Formula E racing series..
Finally a video not completely about Tesla! First video I have watched in months!
But still TESLA biased! Basically, saying TESLA design is better than anyone's else . . .
@@pritambissonauth2181 Monro's entire business is now centered around Tesla.
Bunch of crybabies that can't handle the truth that Tesla has the best tech.
@@themonsterunderyourbed9408 Do you understand what you call 'tech'?
Can't wait to buy the Lucid Gravity and travel with it! God damn, so spacious !!!
Is immersion cooling dealt with in this video?
Watch the video
If a cell manufacturer was also made responsible for designing and building the pack I wonder if they would still use round cells over pouch or prismatic given the added complication of designing a pack? To me the round cell concept is much like one engineering group taking the easiest approach for themselves without any consideration of the overall application. Using serpentine cooling strips seems like a nightmare design for high volume production, nevermind safely connecting all those small cells together. And filling the pack with unpredictable expanding foam is a terrible idea in a production environment. One small change I've noticed in one of Hyundai/Kia newer battery pack designs is to using larger pouch cells to eliminate having 3 in parallel, now 96 cells in total instead of 294. Cell balancing is improved because 2 cells can't support a lagging third. And repairability of packs must become a required feature eventually.
Sandy, please do a BYD tear down
Could the battery be flooded in oil?
Truly, I would not mind slower supercharging and lower acceleration for a lower cost. I expect to supercharge my car very few times per year.
Porsche did this(oil cooling via submersion) with the cayman gt4 awd dual motor 1,008 hp e demonstrator.
I have an electric dirtbike (Caofen FX) with an oil cooled 72v60ah battery. its enclosed in an aluminum alloy case and filled with what appears to be mineral oil and also has a built in battery heater that supposedly works in 40 below zero. I almost want to open the thing up to see what's inside. I think this method of cooling would be cost effective and simpler.
excellent
So i guess if the 2 metal cases of 2 batteries in series touch, there will be a short, but if in parallel, they won't?
You could maybe say that they short in the sense that they create a shorter electrical pathway, but then they're electrically connected anyway; that's what makes them parallel.
Great stuff, Tom! I have been waiting for Munro & assoc. to mention thermodynamics. I have questions about Tesla's choice of side cooling the 4680. That cell is ideal for end cooling yet we see side cooling every second row on the structural pack. It seems obvious that there will be a large temperature gradient within each cell as the side away from the cooling channel has a much longer heat path that for instance in Tesla's 2170 and 18650 packs. This cooling scheme seems to greatly reduce any thermal advantage from the anode and cathode end tabs. Does the rigid support material foamed into the structural pack have particularly high thermal conductivity?