Battery temp management for new leaf

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lorenfb said:
johnlocke said:
edatoakrun said:
It would have been an odd decision, IMO to add either liquid cooling or pack insulation to the 2018 LEAF.

Even more bizarre, would be to add it to only some of (the likely lower production volume, higher capacity pack versions) the 2019 LEAFs.

Adding either feature is relatively trivial from an engineering standpoint, though very expensive in terms of production cost and efficiency.

If Nissan saw any benefit, why did it not add either or both features to the 2018 MY?

So, while anything is possible, until a high integrity source reports otherwise, I think we should expect Nissan to retain passive thermal management, primarily utilizing conductive cooling, in all 2019 MY LEAFs.

Either or both pack designs could use suppplementary active air cooling, much as some other BEV manufactures have, which is very low cost, but provides minimal benefits in terms of reducing battery temperature.

I'd regard blowing air from the standard AC system over the cell cases as mainly a placebo for those suffering from capacity loss anxiety, but it would allow Nissan to tout this benefit, to those misinformed buyers for which it could be appealing.
Air cooling via internal fans would be relatively cheap to do and have a minimal drain on the battery. Even a small airflow will remove a surprising amount of heat. MIght not help much while driving but could certainly help during charging. Could also cool down the battery while parked particularly overnight. It would have to be better than sitting in stagnant air trying to cool. I suppose that you could even vent into the rear passenger compartment for a little extra heat in the winter and dump it outside in the summer.

It depends how the battery is mounted/attached to the vehicle's chassis and the thermal resistance between
the battery and the chassis. If the thermal resistance is effectively zero, then the fans must also cool the
vehicle's chassis to cool the battery.
The battery is bolted onto the chassis. There aren't any thermal transfer pads and the battery is a sealed unit. The chassis is probably cooler than the battery anyway. The only reason that Nissan didn't implement cooling for the battery is cost. They are using the same battery casing and chassis to save money. Probably short-sighted on their part since it looks like the failure rate on the 16-17 30KWH batteries is going to be higher than the old 24KWH batteries. The 40KWH batteries are likely to have even more heat problems just because they will charged for longer periods and are capable of higher current draw(150 HP motor). There are rumors that the 60 KWH battery will require a TMS just for that reason.

My point was that regardless of the details, fan cooling would still be better than just leaving the battery sitting in still air and trying to cool itself by convection. If you could implement an air tunnel through the center with heatpipes to transfer heat from the battery stacks to the tunnel that would be even better.
 
johnlocke said:
lorenfb said:
johnlocke said:
Air cooling via internal fans would be relatively cheap to do and have a minimal drain on the battery. Even a small airflow will remove a surprising amount of heat. MIght not help much while driving but could certainly help during charging. Could also cool down the battery while parked particularly overnight. It would have to be better than sitting in stagnant air trying to cool. I suppose that you could even vent into the rear passenger compartment for a little extra heat in the winter and dump it outside in the summer.

It depends how the battery is mounted/attached to the vehicle's chassis and the thermal resistance between
the battery and the chassis. If the thermal resistance is effectively zero, then the fans must also cool the
vehicle's chassis to cool the battery.
The battery is bolted onto the chassis. There aren't any thermal transfer pads and the battery is a sealed unit. The chassis is probably cooler than the battery anyway. The only reason that Nissan didn't implement cooling for the battery is cost. They are using the same battery casing and chassis to save money. Probably short-sighted on their part since it looks like the failure rate on the 16-17 30KWH batteries is going to be higher than the old 24KWH batteries. The 40KWH batteries are likely to have even more heat problems just because they will charged for longer periods and are capable of higher current draw(150 HP motor). There are rumors that the 60 KWH battery will require a TMS just for that reason.

My point was that regardless of the details, fan cooling would still be better than just leaving the battery sitting in still air and trying to cool itself by convection. If you could implement an air tunnel through the center with heatpipes to transfer heat from the battery stacks to the tunnel that would be even better.

"The battery is bolted onto the chassis. There aren't any thermal transfer pads and the battery is a sealed unit."

So the thermal resistance to the chassis is zero, right? Then using fans will have minimal effect cooling the battery,
since they will also attempt to cool the chassis (the chassis and the battery will always be at the same temp).

Please explain your rational.
 
lorenfb said:
johnlocke said:
lorenfb said:
It depends how the battery is mounted/attached to the vehicle's chassis and the thermal resistance between
the battery and the chassis. If the thermal resistance is effectively zero, then the fans must also cool the
vehicle's chassis to cool the battery.
The battery is bolted onto the chassis. There aren't any thermal transfer pads and the battery is a sealed unit. The chassis is probably cooler than the battery anyway. The only reason that Nissan didn't implement cooling for the battery is cost. They are using the same battery casing and chassis to save money. Probably short-sighted on their part since it looks like the failure rate on the 16-17 30KWH batteries is going to be higher than the old 24KWH batteries. The 40KWH batteries are likely to have even more heat problems just because they will charged for longer periods and are capable of higher current draw(150 HP motor). There are rumors that the 60 KWH battery will require a TMS just for that reason.

My point was that regardless of the details, fan cooling would still be better than just leaving the battery sitting in still air and trying to cool itself by convection. If you could implement an air tunnel through the center with heatpipes to transfer heat from the battery stacks to the tunnel that would be even better.

"The battery is bolted onto the chassis. There aren't any thermal transfer pads and the battery is a sealed unit."

So the thermal resistance to the chassis is zero, right? Then using fans will have minimal effect cooling the battery,
since they will also attempt to cool the chassis (the chassis and the battery will always be at the same temp).

Please explain your rational.
Tell that to Toyota and to Renault, since they both use active air cooling and both have MUCH better battery stories than Nissan.
True though, that I don't know if the air cooling is around the battery case or inside. I have always presumed the latter but I don't know that for sure.
 
SageBrush said:
Tell that to Toyota and to Renault, since they both use active air cooling and both have MUCH better battery stories than Nissan.

Which Toyota? The original RAV4EV had a NiMH battery, with no forced cooling, which had very good life. The second had a Tesla pack with liquid active cooling.

What Renault? Not sold in the USA.

The Ford Focus Electric has active liquid cooling, and does not seem to do better than the Leaf.

Battery life is a messy, complex subject. Amazing how many "experts" there are out there.
 
All this discussion or other cars' battery cooling is irrelevant to the Leaf.

The Leaf has what it has, and talking about the others is like saying that your neighbor has a nicer house than you.... So? Nissan is not going to give a hoot about what you think they should do... Buy or don't buy, That is our part that we can control....
 
SageBrush said:
WetEV said:
SageBrush said:
Tell that to Toyota and to Renault, since they both use active air cooling and both have MUCH better battery stories than Nissan.

Which Toyota?

What Renault? Not sold in the USA..
Prius, Prius Prime
Zoe

Prius has NiMH battery, which is very heat tolerant. Is cooled by cabin air exhaust.

Battery chemistries are very different.

PP is new.
 
WetEV said:
SageBrush said:
WetEV said:
Which Toyota?

What Renault? Not sold in the USA..
Prius, Prius Prime
Zoe

Prius has NiMH battery, which is very heat tolerant. Is cooled by cabin air exhaust.

Battery chemistries are very different.

PP is new.
Prius also had Li battery version
Zoe
I know Prime is new; my point is that Toyota thought it worthwhile to engineer active cooling. Toyota may be a bit slow jumping into the BEV arena but their engineering is top notch.
 
lorenfb said:
"The battery is bolted onto the chassis. There aren't any thermal transfer pads and the battery is a sealed unit."

So the thermal resistance to the chassis is zero, right? Then using fans will have minimal effect cooling the battery,
since they will also attempt to cool the chassis (the chassis and the battery will always be at the same temp).

Please explain your rational.

It sounds more like his claim is that the thermal resistance to the chassis is quite high. The sentences you quote claim that the battery is well insulated from the chassis, thermally speaking.
 
GetOffYourGas said:
lorenfb said:
"The battery is bolted onto the chassis. There aren't any thermal transfer pads and the battery is a sealed unit."

So the thermal resistance to the chassis is zero, right? Then using fans will have minimal effect cooling the battery,
since they will also attempt to cool the chassis (the chassis and the battery will always be at the same temp).

Please explain your rational.

It sounds more like his claim is that the thermal resistance to the chassis is quite high. The sentences you quote claim that the battery is well insulated from the chassis, thermally speaking.

So no one really knows what the overall design parameters were/are for TMS being used in a Leaf.
Please, no more guessing!
 
I may be the only one on the forum who feels this way, but I will never buy (or lease) an EV that requires active cooling to keep its battery alive. I routinely park for extended time in locations where I cannot plug in so active cooling would be of no benefit while parked (and might even discharge the battery trying to keep it cool). I suspect that battery chemistries which require active cooling would deteriorate in my climate more while parked than the Leaf battery does. Active cooling is probably a benefit if a car will be driven long distances each day with multiple quick charging sessions, but I have other vehicles for long trips.
 
GerryAZ said:
I may be the only one on the forum who feels this way, but I will never buy (or lease) an EV that requires active cooling to keep its battery alive. I routinely park for extended time in locations where I cannot plug in so active cooling would be of no benefit while parked (and might even discharge the battery trying to keep it cool). I suspect that battery chemistries which require active cooling would deteriorate in my climate more while parked than the Leaf battery does. Active cooling is probably a benefit if a car will be driven long distances each day with multiple quick charging sessions, but I have other vehicles for long trips.
Phoenix is a tough go for sure, and your use profile just adds to the difficulties.

Tesla owners seem to do quite well in Phoenix like environments although I don't know if any of them have your parking behaviors. If you can find parking that is shaded when you arrive the average ambient temperature in the summer is 90F. That is nasty but I don't know if active TMS systems operate at that temperature when parked. And of course we can hope that the charging infrastructure will continue to expand. For now you may be right about active TMS in your hands, but passive TMS in Phoenix has already proved to be a failure. Things can only get better, right ?
 
I just skimmed this whole thread because we need TMS in Florida but it wasn't clear to me... has Nissan said whether the new version of the LEAF will have TMS? Or is it still all speculation at this point?
 
SageBrush said:
GerryAZ said:
I may be the only one on the forum who feels this way, but I will never buy (or lease) an EV that requires active cooling to keep its battery alive. I routinely park for extended time in locations where I cannot plug in so active cooling would be of no benefit while parked (and might even discharge the battery trying to keep it cool). I suspect that battery chemistries which require active cooling would deteriorate in my climate more while parked than the Leaf battery does. Active cooling is probably a benefit if a car will be driven long distances each day with multiple quick charging sessions, but I have other vehicles for long trips.
Phoenix is a tough go for sure, and your use profile just adds to the difficulties.

Tesla owners seem to do quite well in Phoenix like environments although I don't know if any of them have your parking behaviors. If you can find parking that is shaded when you arrive the average ambient temperature in the summer is 90F. That is nasty but I don't know if active TMS systems operate at that temperature when parked. And of course we can hope that the charging infrastructure will continue to expand. For now you may be right about active TMS in your hands, but passive TMS in Phoenix has already proved to be a failure. Things can only get better, right ?

I guess I should have mentioned that I do park in the shade when parking for extended time. I do not consider passive TMS (as you call it) to be a failure because my 2015 is doing quite well. I have 46,400 miles and 31 months of use with only one capacity bar loss in spite of above average temperatures for Phoenix the past two summers. The 2011 had already lost one capacity bar on the replacement battery by the time of the crash at 42 months and 50,000 miles.
 
GerryAZ said:
I may be the only one on the forum who feels this way, but I will never buy (or lease) an EV that requires active cooling to keep its battery alive. I routinely park for extended time in locations where I cannot plug in so active cooling would be of no benefit while parked (and might even discharge the battery trying to keep it cool). I suspect that battery chemistries which require active cooling would deteriorate in my climate more while parked than the Leaf battery does. Active cooling is probably a benefit if a car will be driven long distances each day with multiple quick charging sessions, but I have other vehicles for long trips.

The airport parking has 120 volt plugs for vehicles and I don't know the additional or other long term parking that you do. I might disagree that other car chemistry's won't hold up better than Leaf in hot temperatures even without active cooling. But... they have been smart to provide active cooling. I agree that having to cool or heat the battery is not as efficient.

Nissan has not been successful with changing chemistry and not cooling our batteries. They need to provide cooling to customers now, and continue in their Experimental Department to maybe develop a non thermal battery management, if that is even possible. If (or when) they perfect it, then put it in our cars.

Most cars only need a 120 volt outlet to plug in for long periods of non use or inactivity. Hopefully soon, you can get rid of your ice for an affordable long distance all electric vehicle. I, myself, am wanting an all electric Pickup truck.
 
GerryAZ said:
SageBrush said:
GerryAZ said:
I may be the only one on the forum who feels this way, but I will never buy (or lease) an EV that requires active cooling to keep its battery alive. I routinely park for extended time in locations where I cannot plug in so active cooling would be of no benefit while parked (and might even discharge the battery trying to keep it cool). I suspect that battery chemistries which require active cooling would deteriorate in my climate more while parked than the Leaf battery does. Active cooling is probably a benefit if a car will be driven long distances each day with multiple quick charging sessions, but I have other vehicles for long trips.
Phoenix is a tough go for sure, and your use profile just adds to the difficulties.

Tesla owners seem to do quite well in Phoenix like environments although I don't know if any of them have your parking behaviors. If you can find parking that is shaded when you arrive the average ambient temperature in the summer is 90F. That is nasty but I don't know if active TMS systems operate at that temperature when parked. And of course we can hope that the charging infrastructure will continue to expand. For now you may be right about active TMS in your hands, but passive TMS in Phoenix has already proved to be a failure. Things can only get better, right ?

I guess I should have mentioned that I do park in the shade when parking for extended time. I do not consider passive TMS (as you call it) to be a failure because my 2015 is doing quite well. I have 46,600 miles and 31 months of use with only one capacity bar loss in spite of above average temperatures for Phoenix the past two summers. The 2011 had already lost one capacity bar on the replacement battery by the time of the crash at 42 months and 50,000 miles.

While you are doing well compared to others, you have lost over 15%. The Nissan battery starts out with some headroom and the first bar is double the rest. If you extrapolate, you will lose 2 more bars in even less time that it took you to lose the first. That all appears to be an acceptable rate to you... for many others it is not. Tesla, for example, is projected to lose 20% in 25-30 years.
 
Evoforce said:
While you are doing well compared to others, you have lost over 15%. The Nissan battery starts out with some headroom and the first bar is double the rest. If you extrapolate, you will lose 2 more bars in even less time that it took you to lose the first. That all appears to be an acceptable rate to you... for many others it is not. Tesla, for example, is projected to lose 20% in 25-30 years.

The expected loss is not linear. It is much steeper at first, and then levels off to a more linear rate. This is the real reason that the first bar is twice the capacity of the rest. The loss of bars should - in theory - be linear in time.
 
That all appears to be an acceptable rate to you... for many others it is not. Tesla, for example, is projected to lose 20% in 25-30 years.

I will eat that Tesla battery if it's any good after 25-30 years. That's nonsense.
 
Joe6pack said:
That all appears to be an acceptable rate to you... for many others it is not. Tesla, for example, is projected to lose 20% in 25-30 years.

I will eat that Tesla battery if it's any good after 25-30 years. That's nonsense.

https://docs.google.com/spreadsheets/d/t024bMoRiDPIDialGnuKPsg/edit#gid=154312675
I would not care to extrapolate out to 25 years but clearly the Tesla battery in a BEV is in a class of its own for now.

uc
 
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