kovadam
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Location: Hungary, Europe

Adding 3rd party cooling to 40kWh battery pack

Fri Jul 13, 2018 1:57 am

Hi!

I am thinking on a way how to add cooling to the traction battery pack. I checked lot of videos about dismounting leaf batteries, even found some Russian videos where the guy was dismounting a 40kWh battery pack.

There is not much space indeed, but I think there would be a way to put some fans and a small heat exchanger into the battery pack. The fans could operate constantly while the car is turned on, it would give a better distribution of the heat across the battery cells, also would probably speed up cooling of the battery pack, since it could give more heat towards the outside. The small heat exchanger (like in the eNV200) could be attached to the on-board A/C units piping, with a valve, which is opened when the battery temperature requires it.

One controller electronics is required to sniff CAN bus messages (like battery temp, is a QC session running, etc) and start the A/C, A/C pump and open the valve towards the battery pack if necessary, so the small heat exchanger inside the battery pack could be cooled down using the A/C. This could start whenever the battery temp is above 25°C.

This will not allow to keep the temp low during QC (it definitely would reduce the heat buildup, but won't prevent it), but would allow to cool down the battery much better till the next QC. (You start with 25°C battery and <20% SOC a QC, it will bring up your temp to 45°C or even above if you charge to >80%. This kind of cooling would probably give you 3-5°C reduction, so you arrive somewhere around 40°C. But when you then start to drive, the cooling would continue and if you drive like 2hrs it would bring down the temp below 30°C, then you would get a full charge speed again.)

The only drawback is, that you have to dismount the battery pack, drill two (eventually three, 1 for the FAN controlling) holes on it to bring the cooling liquid inside, then also inside some piping, installing the FANs and the heat exchanger (find proper fans, proper size heat exchanger for the place available). This will void your warranty definitely. So the question who would sacrifice the 8 year warranty for a battery cooling?

What do you think?

Regards

kovadam

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Stanton
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Re: Adding 3rd party cooling to 40kWh battery pack

Fri Jul 13, 2018 7:02 am

I think if you want to do that much to your car...you need to find another car.
Even if it achieved the goal, I wouldn't want to void the warranty on a brand new car.
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Phatcat73
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Re: Adding 3rd party cooling to 40kWh battery pack

Fri Jul 13, 2018 8:01 am

That's a good way to void your warranty. I wouldn't even consider this route until the 8 yr degradation warranty is expired. By then solid state technology may be released and cooling may no longer be needed. (wishful thinking)
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WetEV
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Re: Adding 3rd party cooling to 40kWh battery pack

Fri Jul 13, 2018 8:31 am

kovadam wrote:I am thinking on a way how to add cooling to the traction battery pack.


A bad idea. Drilling holes in the battery case may admit water, which may cause bad results... corroded connections, even battery fires.

Get a Leaf that is out of warranty, or totaled, or some other way to play.
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Nubo
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Re: Adding 3rd party cooling to 40kWh battery pack

Fri Jul 13, 2018 1:00 pm

kovadam wrote:...found some Russian videos where the guy was dismounting a 40kWh battery pack. ...
...So the question who would sacrifice the 8 year warranty for a battery cooling?...


Russian with a stolen LEAF?
I noticed you're still working with polymers.

kovadam
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Joined: Wed Jun 06, 2018 12:07 am
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Re: Adding 3rd party cooling to 40kWh battery pack

Sat Jul 14, 2018 3:24 am

WetEV wrote:
kovadam wrote:I am thinking on a way how to add cooling to the traction battery pack.


A bad idea. Drilling holes in the battery case may admit water, which may cause bad results... corroded connections, even battery fires.

Get a Leaf that is out of warranty, or totaled, or some other way to play.


You can drill holes on the battery pack without having water, dust, dirt enter the battery pack, since it has already 5 holes on it, and it is not an issue. The key word is here proper sealing of the coolant pipes / FAN connectors which is not a problem.

Totaled car is not good, because you cannot test then the system, but a highly degraded battery pack which is cheap to buy would be a possibility to start testing with. Then may be a cheap Leaf without a battery pack to mount the modified pack and test how it's working.

If it is working well, a company could produce the parts, and may be also bear the warranty for the battery pack (for this, I'm sure an insurance company can help for some additional fee, but it should be in the cooling kit price calculated, then the company would take the warranty instead of Nissan). May be if it is successful, Nissan would consider to implement, support this kind of modification. Who knows.

I'm not saying that the first thing I will do when I finally get my Leaf in September to add cooling to the battery pack, however theoretically it is possible.

kovadam
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Re: Adding 3rd party cooling to 40kWh battery pack

Sat Jul 14, 2018 3:25 am

Nubo wrote:
kovadam wrote:...found some Russian videos where the guy was dismounting a 40kWh battery pack. ...
...So the question who would sacrifice the 8 year warranty for a battery cooling?...


Russian with a stolen LEAF?


Well I'm not in Russia, but probably they would :D

TexasLeaf
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Re: Adding 3rd party cooling to 40kWh battery pack

Tue Jul 17, 2018 8:52 am

The 2019 model is suppose to have TMS and there is going to be very little difference between the 2018 and 2019 models this soon after the 2018 refresh. The form factor of the battery packs of the 2018 and 2019 models even look like the packs would fit on older Leafs. If you don't want to pay for a 2019+ model you can wait until you can pick up a 2019+ wreck and swap battery packs.

The battery overheating issue is not that bad unless you are driving on a 300+ mile trip. And even then there are ways to manage battery overheating, like driving for range instead of speed and driving at night. I think I will wait until my battery pack needs replacement before I will worry about replacing it with a 2019+ battery pack with TMS and by then I will probably want to upgrade to an EV that is a lot more capable (300+ mile range, AWD, real towing capacity, etc.)

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