Possible Widespread 2018-19 Traction Battery Quick Charge Problems

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LeftieBiker said:
No, that's because replacement laptop batteries and cell phone batteries are very cheap and easy to self-install, and the weight of a TMS would be a problem for consumers. If laptop batteries were essentially permanently installed, there would be better cooling systems in them.

My laptop batteries are permanently installed, as are my cell phone batteries. OK, with special tools you can disassemble both and then glue back together. Not for the non-technical, to say the least. I've never seen a cell phone with a battery thermal management system. Or a laptop.

Now for some real reasons. How much battery power would be needed to keep the battery in the cell phone cool for a day? How much bigger would the cell phone battery need to be?

Why are there no warm blooded mammals much smaller than a mouse? Why does a bee humming bird (the smallest warm blooded bird) need to eat well over twice its mass every day... and still can't be warm blooded full time? And cooling is a harder problem than warming.

Heat loss/gain is proportional to surface area. Battery energy storage is proportional to volume. As an object gets smaller, the energy storage goes down faster than the surface area. Get small enough, and it gets harder to maintain at any temperature other than ambient. A laptop is not as thermally insulated as a mouse, has a higher ratio of surface area to volume, because it is thin, and needs to be cooled rather than heated.

Want a laptop or a cell phone with active cooling battery and similar operational time? It would be at least as thick as a brick. Larger battery, thermal insulation, cooling hardware, etc.

I can turn my cell phone off, and the battery will stay at almost the same charge level for months. Same with my laptop, if I shutdown. Same with my Leaf. If there was a TMS system? The shutdown time for a laptop or cell phone would be hardly longer than the operational time. The laptop would drain in a day. Leaf would be much better, would drain the battery in weeks, much as a Tesla will drain to bricked batteries in a few months.

Active cooling isn't free. I don't want it for my laptop or my car.
 
SageBrush said:
Sure it is. A good TMS is a a great thing, everything else being equal.

Actually, not.

I live in a cool place. Assuming my Leaf had a TMS, and that the TMS started to cool at 86F/32C, it would have turned on 14 times in total in the past 2 years, according to my LeafSpy log. Most of the time for less than 2 C. For driving time, 1.7% of the time. I don't have logs for no-driving times, but none of the logs started at or above this temperature. The only way I've noticed such temperatures is a DCQC and a long drive.

If battery life halved on a 10C increase, I might have 1% or less improved battery life.

Hardly great, at best.

Why would I want this added cost, weight, complexity?

Why would I want this reduction in reliability?
 
WetEV said:
Why would I want this added cost, weight, complexity?

To avoid this:

uc
 
SageBrush said:
WetEV said:
Why would I want this added cost, weight, complexity?

To avoid this:

This is a chart of reported bar losses, not how far you can expect to drive before losing a bar. Having not lost a bar, my car isn't on it. As is every car that hasn't lost a bar.

I don't see anything there that makes me want a TMS. Active cooling would only be working less than 1.7% of my driving time, and probably less than 0.1% of total time. The gain in battery life would be microscopic.

I like it how Leaf batteries don't catch fire, unlike Tesla's batteries. Sure, gasoline is even worse.
 
WetEV said:
This is a chart of reported bar losses, not how far you can expect to drive before losing a bar.
Look at the chart again.

E.g., there is about an 80% chance a LEAF owner will drop a bar by the time they drive 40k miles.
 
SageBrush said:
WetEV said:
This is a chart of reported bar losses, not how far you can expect to drive before losing a bar.
Look at the chart again.

E.g., there is about an 80% chance a LEAF owner will drop a bar by the time they drive 40k miles.

Notice again that is a chart of currently reported bar losses. Leafs that have not lost a bar are not on that chart. My car is not on that chart, as I have yet to lose a bar. This is not how far you can drive before losing a bar. Those are two different things, unless all cars have lost a bar.

I'm past 40k miles, and perhaps a year or two or three and 10k to 30k more miles from losing a bar.
 
WetEV said:
SageBrush said:
WetEV said:
This is a chart of reported bar losses, not how far you can expect to drive before losing a bar.
Look at the chart again.

E.g., there is about an 80% chance a LEAF owner will drop a bar by the time they drive 40k miles.

Notice again that is a chart of currently reported bar losses. Leafs that have not lost a bar are not on that chart. My car is not on that chart, as I have yet to lose a bar. This is not how far you can drive before losing a bar. Those are two different things, unless all cars have lost a bar.

I'm past 40k miles, and perhaps a year or two or three and 10k to 30k more miles from losing a bar.
I understand your argument but there is no good reason to think it will apply here. Just look at the histogram shape.
 
SageBrush said:
I understand your argument but there is no good reason to think it will apply here. Just look at the histogram shape.

My car is not on that chart. And when it gets put on that chart, I'm already past 40k miles. As is a co-worker's Leaf, a 2013 SV with almost 60k miles.

A TMS would not increase my battery life. My battery stays too cool almost all the time for active cooling to do anything.

As the co-worker doesn't QC, I suspect active cooling would do exactly nothing for his battery life. Yes, he has the option to do so, but has done so exactly once. Mostly just to try it out.

I'd rather not pay for active cooling, my battery life isn't improved by active cooling, and I'd rather not have a battery pack that catches fire like a T esla.
 
WetEV said:
SageBrush said:
I understand your argument but there is no good reason to think it will apply here. Just look at the histogram shape.

My car is not on that chart. And when it gets put on that chart, I'm already past 40k miles. .

<<sigh>>
I know it is not. And when it is the bars are not going to change. There are too few of you to matter. You are in the 4% group.
 
I'd rather not pay for active cooling, my battery life isn't improved by active cooling, and I'd rather not have a battery pack that catches fire like a T esla.

Do you believe that it's the cooling system that causes the Tesla fires? Do you think that if Nissan added a TMS to the Leaf pack, that it would then be prone to catching fire?
 
WetEV said:
SageBrush said:
I understand your argument but there is no good reason to think it will apply here. Just look at the histogram shape.

My car is not on that chart. And when it gets put on that chart, I'm already past 40k miles. As is a co-worker's Leaf, a 2013 SV with almost 60k miles.

A TMS would not increase my battery life. My battery stays too cool almost all the time for active cooling to do anything.

As the co-worker doesn't QC, I suspect active cooling would do exactly nothing for his battery life. Yes, he has the option to do so, but has done so exactly once. Mostly just to try it out.

I'd rather not pay for active cooling, my battery life isn't improved by active cooling, and I'd rather not have a battery pack that catches fire like a T esla.

That's a strawman argument. Active cooling doesn't mean actively cooling 100% of the time. During QC, when temps can reach well above 100F, active cooling helps and is only really needed for long enough to bring the temps to ambient. When parked, why would the TMS turn on if the battery's at ambient temps? Even in AZ, it's not above 100F the entire day.

Then there's the added benefit of a warmed battery while charging that gives you more usable range. If temps drop below freezing, the battery isn't going to degrade from that, just have less usable range for the day. Much more preferable to a permanently capped range.
 
Oils4AsphaultOnly said:
WetEV said:
A TMS would not increase my battery life. My battery stays too cool almost all the time for active cooling to do anything.

As the co-worker doesn't QC, I suspect active cooling would do exactly nothing for his battery life. Yes, he has the option to do so, but has done so exactly once. Mostly just to try it out.

I'd rather not pay for active cooling, my battery life isn't improved by active cooling, and I'd rather not have a battery pack that catches fire like a T esla.

That's a strawman argument. Active cooling doesn't mean actively cooling 100% of the time. During QC, when temps can reach well above 100F, active cooling helps and is only really needed for long enough to bring the temps to ambient.

In exactly one of the 64+ QCs to date, temperatures exceeded 100F. All the way to 101.1F or 38.4C. I don't want to pay for hardware that will almost never get used. I know that I never exceeded 100F with my 2012, but I don't have a count of QCs for my 2012.

Perhaps it is different were you live. I don't see any utility for me from active cooling.
 
WetEV said:
Oils4AsphaultOnly said:
WetEV said:
A TMS would not increase my battery life. My battery stays too cool almost all the time for active cooling to do anything.

As the co-worker doesn't QC, I suspect active cooling would do exactly nothing for his battery life. Yes, he has the option to do so, but has done so exactly once. Mostly just to try it out.

I'd rather not pay for active cooling, my battery life isn't improved by active cooling, and I'd rather not have a battery pack that catches fire like a T esla.

That's a strawman argument. Active cooling doesn't mean actively cooling 100% of the time. During QC, when temps can reach well above 100F, active cooling helps and is only really needed for long enough to bring the temps to ambient.

In exactly one of the 64+ QCs to date, temperatures exceeded 100F. All the way to 101.1F or 38.4C. I don't want to pay for hardware that will almost never get used. I know that I never exceeded 100F with my 2012, but I don't have a count of QCs for my 2012.

Perhaps it is different were you live. I don't see any utility for me from active cooling.

Do you pay for AC for your car? Did I pay for heat for mine? Just because it might not be used [Edit: "as in used by you"], doesn't mean it's useless.
 
Oils4AsphaultOnly said:
WetEV said:
In exactly one of the 64+ QCs to date, temperatures exceeded 100F. All the way to 101.1F or 38.4C. I don't want to pay for hardware that will almost never get used. I know that I never exceeded 100F with my 2012, but I don't have a count of QCs for my 2012.

Perhaps it is different were you live. I don't see any utility for me from active cooling.

Do you pay for AC for your car? Did I pay for heat for mine? Just because it might not be used [Edit: "as in used by you"], doesn't mean it's useless.

I'm old enough that I've bought two cars with no AC. It used to be an option...But the take rate rose with time, until it was cheaper to just make all cars with it.

So what would the take rate be if active cooling was an option?

I'd guess fairly low locally, and might not be very large in moderate climates, most of the USA. Fairly high in Arizona and the rest of the Southern USA. 20% active cooling? 80% active cooling? Hard to say, as might depend on lots things not known. Less on small battery cars, more on larger battery cars. The gain is larger, the larger the battery, and the cost is similar. Also small battery cars are more likely to be commuter cars, where QC isn't common, than performance cars, where multiple QCs per day at high power is a bragging point, if not more common.

Active cooling isn't just extra cost, and isn't just reducing reliability, but also may be reducing battery life in cool places. That is worse than useless.
 
WetEV said:
Oils4AsphaultOnly said:
WetEV said:
In exactly one of the 64+ QCs to date, temperatures exceeded 100F. All the way to 101.1F or 38.4C. I don't want to pay for hardware that will almost never get used. I know that I never exceeded 100F with my 2012, but I don't have a count of QCs for my 2012.

Perhaps it is different were you live. I don't see any utility for me from active cooling.

Do you pay for AC for your car? Did I pay for heat for mine? Just because it might not be used [Edit: "as in used by you"], doesn't mean it's useless.

I'm old enough that I've bought two cars with no AC. It used to be an option...But the take rate rose with time, until it was cheaper to just make all cars with it.

So what would the take rate be if active cooling was an option?

I'd guess fairly low locally, and might not be very large in moderate climates, most of the USA. Fairly high in Arizona and the rest of the Southern USA. 20% active cooling? 80% active cooling? Hard to say, as might depend on lots things not known. Less on small battery cars, more on larger battery cars. The gain is larger, the larger the battery, and the cost is similar. Also small battery cars are more likely to be commuter cars, where QC isn't common, than performance cars, where multiple QCs per day at high power is a bragging point, if not more common.

Active cooling isn't just extra cost, and isn't just reducing reliability, but also may be reducing battery life in cool places. That is worse than useless.

Warming has increased the need for AC. I used it briefly last week and the temps were in the mid 60's but the solar effects made it very uncomfortable in the car. In town it was ok to roll around with windows down but on the freeway, it was A/C...

One that has not been mentioned here is that Nissan picked one of the worst chemistries for heat tolerance. Now that formula has been tweaked constantly but the results do not appear to be trending consistently... to say the least
 
DaveinOlyWA said:
One that has not been mentioned here is that Nissan picked one of the worst chemistries for heat tolerance. Now that formula has been tweaked constantly but the results do not appear to be trending consistently... to say the least

Yes. One of the worst for heat tolerance, but also one of the best for safety. No battery pack fires, unlike T esla.
 
WetEV said:
DaveinOlyWA said:
One that has not been mentioned here is that Nissan picked one of the worst chemistries for heat tolerance. Now that formula has been tweaked constantly but the results do not appear to be trending consistently... to say the least

Yes. One of the worst for heat tolerance, but also one of the best for safety. No battery pack fires, unlike T esla.

Nissan didn't have to change the chemistry, they just had to make the passive cooling as effective (preferably more effective) as it is in the 24kwh packs. Instead they appear to have made it LESS effective.
 
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