Featured Nissan Leaf vs Chevy Bolt battery management system

part of the equation will be price. no one knows how many potential plug in buyers are savvy to thermal management. we probably take it for granted that many (most) are aware due to sites like prius chat and the like.
if air cooling works decently, and can be done cheaply enough to offer a similar car a price point that gets attention, it sell very well.

 

The rumor is the 60 kwh leaf will use liquid cooled ncm 811 cells which are smaller and less expensive (they may be as heavy) than those in the current bolt pack, but not available until this summer. Here is a good comparison of the bolt versus tesla cooling design. GM Versus Tesla: Bolt EV And Model 3 Battery Packs Compared

 

Air cooled large battery packs have more expensive battery cells. Today's technology likely makes a 60 kwh air cooled battery pack more expensive but lighter than a 60kwh liquid conditioned pack.

 

then that would eliminate any reason to not go liquid?

 

Very small packs like that in the prime might be better air cooled, but get much bigger and today's battery prices say liquid ;-) unless simplicity is more important than cost and reliability. Who knows about technology in 5 years. My guess is a plate system like that in a i3 and bolt will be used in the 60 kwh leaf..

bolt has a 60 kwh pack weighing 960 lbs
Prime has a 8.8 kwh pack weighing 265 lbs.

Somewhere between these 2 values liquid cooled wins especially if the pack can be used as a structural element in the car.

Additional information - on the bolt the cooling plates are estimated to be around 2 pounds each and their are 10 of them. On a 18 kwh pack I'd expect 3 or 6 pounds + maybe 30 pounds for radiator and other cooling stuff - call it 35 pounds. The casing may need to be a little heavier to provide protection for the cooled pack, which on the bolt is about 4 pounds/kwh.

 

non sequiter

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only for you.

 

Several other folks too, that got seriously burned (pun intended) with air cooled.
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they've already moved on to chevy. wait, did they also get burned on the ev1?

 

Lease only, never offered for sale.

 

it will sell better, if the perspective owners don't bother to read the precautions as they go through their warranty. From the OP's article;

wow - not storing the car in hot environments? Ok, good thing all of us folks that have 95°+ summer weather ALSO have a beachfront home around the San Francisco bay, to protect our delicately/crappy traction Leaf batteries.
Oh!! And whatever you do, don't charge the car after you use it. (rolling eyes) That's going to make for some mighty expensive X-country trips, getting a hotel every 150 miles, while your traction pack cools down. Make sure your journey isn't in a hot place while you're at it. I wouldn't have believed reading this .... if i hadn't read that Nissan actually published it. But what's a crappy battery car manufacturer going to do .....
You either tell your buyers up front so they can't sue you for failing to disclose their battery packs are potentially self cooking, or you publish these truths - so you can't get sued, like what happened to Nissan with their 1st few years worth of self cooking Leaf battery cars. Oh well, at least they're cheaper than other BEV's.

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Whether buyers are aware of thermal management or not doesn’t matter.

Nearly all folks I talk to figure the battery in my Volt degrades so much it needs replacement every 5 years.

We can thank Nissan for making that misconception get rooted in by screwing early adopters with a battery that really is almost useless every 5 years.


Every time, I have to repeatedly explain my Volt is very different than a leaf and at 5 years old it actually has gained about a 1/10 kwhr capacity validated off the wall, compared to the day it left the lot.

I’ve even had to explain that to folks that own leafs who figure Chevies quality is much more terrible than Nissan.

Sort of like having a conversation about how your liberal Chevy is aging better than their republican Nissan.

 

Having owned both types of cooling in PHEV designs (VOLT, ENERGI), this subject is of keen interest to me. I've followed both vehicles since inception through today and see these pro's and cons of each.

Air cooled: simple, cheap, reliable, lighter, easy to work on. Heat issues cause a loss in capacity over time.
Liquid cooled: complex, expensive, heavier, lower reliability due to complexity, difficult to work on. Better heat management, less capacity loss over time.

My anecdotal evidence from watching those forums for both vehicles have led me to the conclusion that I prefer for long term ownership (IN A PHEV DESIGN) the range loss issue of the air-cooled pack over the reliability issues of the liquid cooled design. Philosophical view: I'd rather reach my destination having burned a little gas than to have not arrived at all.

In a BEV, it's got to liquid cooled: The packs are too big and too dense (tremendous heat sinks) along with the need for quick charging speeds that creates tremendous heat as a by-product.

 

In theory your words sound good but I know a few folks that tried to sue ford because their energi lost over half its EV range in a few years, their fuel economy also dropped.

Ford doesn’t warranty capacity loss.

I think an EV is too large of an investment to skimp on battery thermal management.

At that
Sparkie the Volt is still on the road with 428,000 miles it’s original battery with 2% degradation and some issues starting to form in the last 5000 miles that don’t keep it from driving .

https://www.voltstats.net/Stats/Details/1579

I rather have minor maintenance like a temperature sensor, wheel bearings and fluid changes in 428,000 miles than have my EV range tank and have to replace the battery every 5 years

 

The volt battery design choice means one purchases additional battery capacity up front. That's nearly 6 kWhr of capacity purchased but never used and taking up a lot of interior space. Toyota has shown manufactures will drop the pack prices down the road. I rather purchased that 6 kWhr's in the future at a cheaper price and get to a "new" car again. And just like my Gen2, it's something I can DIY.

FWIW

 

as the medium becomes more sophisticated, and users increase, this type of knowledge will also increase and change buying habits.
but in this infancy, i do believe many will purchase without knowledge and due diligence. you can see it here over and over again. newbies first posts: 'i just bought a prius and nobody told me...'

 

Doesn't the PiP and Prime manual warn against charging right after driving?

 

Duno - but a PHEV puts no where NEAR as much of a load on its traction pack as an EV does. And the only PHEV that charges at L3 is the Outlander - all the rest of the PHEV's only charge at 3 or 6kW's ... so that too, is really not that much heat generation.
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yes, and also leaving the car charged for long periods of time. these are the kind of things that savvy buyers will weigh, and innocent newbies will stumble on.
and sales people will likely be of little help.