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The reason DC fast charging beyond specifications could contribute is that it can cause dendrites and other swelling within the pouch, which over time could make the cell more susceptible to fires when under pressure by a faulty separator.
Right. So the solution is to limit the cause of the damage, not limit the top charge level where the damage becomes evident. Unless you just accept the damage and look for the results of the damage in software, which seems like a poor solution.
 

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Right. So the solution is to limit the cause of the damage, not limit the top charge level where the damage becomes evident. Unless you just accept the damage and look for the results of the damage in software, which seems like a poor solution.
No, the solution is to replace the cells/modules with faulty separators because, eventually, those cells will catch fire, regardless of the other precautions taken.
 

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No, the solution is to replace the cells/modules with faulty separators because, eventually, those cells will catch fire, regardless of the other precautions taken.
How does that solve the issue of charge rate being the root cause of the problem (your point)? I suppose you're implying that it's a dual issue of faulty separators and charge rate causing the defect to become evident. If that's the case, the software solution would still be the same... reduce the maximum charge rate.
 

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How does that solve the issue of charge rate being the root cause of the problem (your point)? I suppose you're implying that it's a dual issue of faulty separators and charge rate causing the defect to become evident. If that's the case, the software solution would still be the same... reduce the maximum charge rate.
I didn't say it was the root cause. I said it exacerbates the problem, hence there were more Kona Electric fires per unit sold than Bolt EV fires.
 

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How does that solve the issue of charge rate being the root cause of the problem (your point)? I suppose you're implying that it's a dual issue of faulty separators and charge rate causing the defect to become evident. If that's the case, the software solution would still be the same... reduce the maximum charge rate.
If faster charging than is safe contributes to dendrites piercing the separator, a slower charge rate may reduce or delay the inevitable. At the end of the day, if the separator is sub-standard, it will eventually fail.

It seems the speculation is around how a percentage of battery cells were manufactured with substandard separators. Apparently, LG\GM were more effective at identifying these before they went into cells, but a small percentage slipped through the cracks. Hyundai presumably focussed less on this important QA step and seems to have a higher rate of failure. When LG\GM started making 2019 Bolt batteries in MI mid-year, they presumably contracted with a different supplier for the separator, and feel confident this results in lower failure rates.
 

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I would assume that the software fix will not shut the car down when a fault is found, but rather reduce the charging capacity to something less than 100% (like currently) and pop up a message about the fault. I would also assume an extended warranty relating to this specific battery fault versus normal degradation. A free battery repair would likely not be ignored by most owners. There will always be some unhappy owners, but this should be an acceptable remedy to most of us in my opinion.
 

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I would assume that the software fix will not shut the car down when a fault is found, but rather reduce the charging capacity to something less than 100% (like currently) and pop up a message about the fault. I would also assume an extended warranty relating to this specific battery fault versus normal degradation. A free battery repair would likely not be ignored by most owners. There will always be some unhappy owners, but this should be an acceptable remedy to most of us in my opinion.
I feel like some people are looking for a free upgrade out of this. I'm of the opinion that, if it ain't broke, why should I bother fixing it?
 

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No, the solution is to replace the cells/modules with faulty separators because, eventually, those cells will catch fire, regardless of the other precautions taken.
Well, that is the "best solution" for the customer. (us) But, IF they can provide a software solution that gets people back their 100% available battery and scans for "problem" packs. And then flags the car for cell/pack replacement in that case...
(Which might be exactly what you were saying as I re-read this..)
That might be the best solution for GM and an acceptable solution for their owners.
The real question for me around this is, how long is this good for?
Would they do this for the life of the pack? (i.e. as long as the car is driving)
Would they do this for the warranted life of the pack? (which could be MUCH less)
Would they do this for an extended period? (150,000 or 200,000 miles? something like that?)
So, I am not saying GMs solution is the wrong option.
But as a high(ish) mileage Bolt owner who was planning on keeping the car for a while, I am watching...
 

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September of 2019 was the first...two and three quarter years after the first Bolts were delivered in December of 2016.

I know, I was being silly.
 

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No, the fires have typically been associated with packs that were charged to 100%. Because the issue appears to be the separators, the more full the battery is, the more likely there is severe pressure on the separators.

The reason DC fast charging beyond specifications could contribute is that it can cause dendrites and other swelling within the pouch, which over time could make the cell more susceptible to fires when under pressure by a faulty separator.
Do we know if the Konas that caught fire had been doing a lot of high DCFC?
 

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I try to remember: "Those who don't know, talk, those who know, don't talk."
Is GM obliged to disclose the root cause to the public?
 

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Do we know if the Konas that caught fire had been doing a lot of high DCFC?
No, which is why I said:

It's also very likely that Hyundai's approach and design exacerbated the fire risk. As far as anyone can tell, the Bolt EV and Kona's cells are nearly identical. These cells are rated at a maximum 1 C charging rate. The Bolt EV's peak charging rate is .9 C. The Kona Electric's peak charging rate is 1.1 C. So Hyundai made the decision to exceed cell specifications by over 10%.
 

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Totally agree.
Although I do wonder about the warranty part...
I'm over 80k now. I'd hate to get notified at 125k of the issue and be out of warranty (assuming it is tied to the current or just a bit over), so this is something I will be watching.
They will almost certainly be extending the battery warranty, some time down the road. They simply can't have an owner with 125k miles with a bad cell who refuses to get the battery back replaced for $10k+, then the car starts on fire. My Hyundai and my Kia both got a LIFETIME engine warranty in a court settlement, due to a fire situation, and I would be very surprised if GM wasn't held to a similar standard. They will almost certainly have to extend the battery warranty to 150k miles, like New Jersey already has now, and most likely even further than that. They may not include battery "degradation", but they will have an extended warranty for any dangerous situation for sure. It will just take time in the courts.
 

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They will almost certainly be extending the battery warranty, some time down the road. They simply can't have an owner with 125k miles with a bad cell who refuses to get the battery back replaced for $10k+, then the car starts on fire. My Hyundai and my Kia both got a LIFETIME engine warranty in a court settlement, due to a fire situation, and I would be very surprised if GM wasn't held to a similar standard. They will almost certainly have to extend the battery warranty to 150k miles, like New Jersey already has now, and most likely even further than that. They may not include battery "degradation", but they will have an extended warranty for any dangerous situation for sure. It will just take time in the courts.
This is my expectation as well.
 

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Except, they haven't had 4 years to work on this. It hasn't been that long that they had enough information to know there was an actionable problem.
As for designing a system without ANY defensive code, I think that's wrong also.
I am sure they had a lot of defensive code in there.
What they didn't have was code that caught this particular event.
That happens...
And there are almost always engineers/developers saying they disagree with things. Sometimes they are right. Sometimes not.
Time will tell, but I don't presume to know what actually is happening here with the information we have seen.

Have a good one.
Bolts have been having fires since day one?
Ha ha! No. But the failure mode of Lithium batteries (i.e. their propensity to burn), is well-known and understood from what's been learned through their use in smaller devices.

So here you are scaling everything up into these "monster" battery packs, and putting them in automobiles for people to drive around in. The stakes are very high - from both a safety and business-image standpoint. You want this to succeed because you say it's the future of your company. So then you need to do everything possible to ensure there isn't a single fire with these batteries! And that means you need extensive fire-detection logic in your BMS, and you also need to continue lab testing - even after the vehicles are out there - to try to uncover any weaknesses that may not show up immediately.

And I can already hear people reading this and saying: "it was only 4 battery packs out of 70,000 ... how are you going to find that?"

Yeah .. I'd buy that if these 4 vehicles all failed under different, and very peculiar, circumstances. But they didn't. They all failed pretty much the same way: sitting still, having been charged recently.

So ... cars can sit still and be repeatedly charged in a GM lab environment, right? They had 4 years to do this and neither they (nor their BMS software) were able to find this problem before one of their customers did?

I'm sorry, but they dropped the ball here. And now they're scrambling to do what they should've done at the beginning, or certainly could've done over the last 4 years, and it's taking them an eternity to come up with their (better-late-then-never) "solution".
 

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I'm sorry, but they dropped the ball here. And now they're scrambling to do what they should've done at the beginning, or certainly could've done over the last 4 years, and it's taking them an eternity to come up with their (better-late-then-never) "solution".
AH, I see what you are saying now..
Yeah, I really totally don't agree with that at all...
:)
Have a good one!
 

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In Korea (where LG and Hyundai both have strong backers in gov't), LG will pay ">50%" of the cost to replace batteries in 25k Konas in Korea (on another site, I read "2/3 of cost", and LG is probably going to split that with the manufacturer of the separator film).

In the US, GM should have a far stronger position in court vs LG Chemical of America. With precedent set in Korea, it should be a "slam dunk" for GM to hit LG with 2/3 of the cost of battery replacements. If I were GM, I would run, not walk, to court and file papers against LG.

Could GM really be pushing a software solution to avoid paying a small portion of the cost of battery replacements? At this point, anything GM does which may keep affected batteries on the road (including a GM software change) only transfers liability from LG to GM.

The question of whether the software change is good enough is moot. LG can be made to pay for new batteries. The more GM talks-up a firmware solution being good enough, the more it undercuts its future court case against LG.
 

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The thread is about: in Korea (where LG and Hyundai both have strong backers in gov't), LG will pay ">50%" of the cost to replace batteries in 25k Konas in Korea (on another site, I read "2/3 of cost", and LG is probably going to split that with the manufacturer of the separator film).

In the US, GM should have a far stronger position in court vs LG Chemical of America. With precedent set in Korea, it should be a "slam dunk" for GM to hit LG with 2/3 of the cost of battery replacements. If I were GM, I would run, not walk, to court and file papers against LG.

Could GM really be pushing a software solution to avoid paying a small portion of the cost of battery replacements? At this point, anything GM does which may keep affected batteries on the road (including a GM software change) only transfers liability from LG to GM.

The question of whether the software change is good enough is moot. LG can be made to pay for new batteries. The more GM talks-up a firmware solution being good enough, the more it undercuts its future court case against LG.
GM has big EV plans with LG. Would GM be able to find a new battery partner if they stomp all over LG? Would they have the expertise to go it alone? Even Tesla partners with battery makers.

It is a balancing act. Just because they could win the battle, would they prevail long term by taking an adversarial position against a key supplier?

If SW can effectively detect the conditions, and if the actual failure rate is relatively low, why wouldn't GM proceed with SW solution for all, and replacements only when defective cells are discovered?
 

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Ha ha! No. But the failure mode of Lithium batteries (i.e. their propensity to burn), is well-known and understood from what's been learned through their use in smaller devices.

So here you are scaling everything up into these "monster" battery packs, and putting them in automobiles for people to drive around in. The stakes are very high - from both a safety and business-image standpoint. You want this to succeed because you say it's the future of your company. So then you need to do everything possible to ensure there isn't a single fire with these batteries! And that means you need extensive fire-detection logic in your BMS, and you also need to continue lab testing - even after the vehicles are out there - to try to uncover any weaknesses that may not show up immediately.

And I can already hear people reading this and saying: "it was only 4 battery packs out of 70,000 ... how are you going to find that?"

Yeah .. I'd buy that if these 4 vehicles all failed under different, and very peculiar, circumstances. But they didn't. They all failed pretty much the same way: sitting still, having been charged recently.

So ... cars can sit still and be repeatedly charged in a GM lab environment, right? They had 4 years to do this and neither they (nor their BMS software) were able to find this problem before one of their customers did?

I'm sorry, but they dropped the ball here. And now they're scrambling to do what they should've done at the beginning, or certainly could've done over the last 4 years, and it's taking them an eternity to come up with their (better-late-then-never) "solution".
By the time we first heard about a Chevrolet Bolt EV fire, GM was already transitioning battery production to the United States with better quality control (based on faulty cells, not faulty separators). So yes, it's completely believable that GM wasn't able to identify this issue before one lucky customer out of every 15,000 found out the hard way.

You could argue that GM should have acted earlier on the fire issue, but the first fire was in the Ukraine, with a U.S. built Bolt EV that was transported overseas under unknown circumstances. It's no wonder GM didn't just drop everything to investigate.
 
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