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Re: Cabin Air Cooling the Battery

Posted: Sun Jul 29, 2018 1:32 pm
by jjeff
The crazy thing is the Nissan eNV-200 does have air cooling, when charging :?
I would think it would quite easy to implement it on the Leaf, if Nissan cared :(

Re: Cabin Air Cooling the Battery

Posted: Mon Jul 30, 2018 12:08 am
by Evoforce
jjeff wrote:The crazy thing is the Nissan eNV-200 does have air cooling, when charging :?
I would think it would quite easy to implement it on the Leaf, if Nissan cared :(


While that might help in some climates, very hot climates, it does not do enough. A person uses their car about 4% of the time. In a hot climate,a battery can be overheated just by setting going nowhere. Kia Soul, which has cabin air battery cooling, has been failing in hot climates. The problem is going to show itself in the Hyundai brand too if they don't end up changing to liquid cooling.

Re: Cabin Air Cooling the Battery

Posted: Mon Jul 30, 2018 12:25 am
by alozzy
The Kona is liquid cooled, so I would assume that all future EVs built by Hyundai will be liquid cooled as well. Perhaps liquid cooling will be added to the IONIQ in the next generation...

Re: Cabin Air Cooling the Battery

Posted: Mon Jul 30, 2018 7:34 am
by WetEV
jjeff wrote:The crazy thing is the Nissan eNV-200 does have air cooling, when charging :?
I would think it would quite easy to implement it on the Leaf, if Nissan cared :(


Easy to implement, perhaps. But not very effective. And liquid cooling has both safety concerns and is more expensive to implement.

There is a real reason why a passive cooled BEV should exist, at least in climates where battery life is reasonable.

Re: Cabin Air Cooling the Battery

Posted: Mon Jul 30, 2018 1:03 pm
by arnis
WetEV wrote:Easy to implement, perhaps. But not very effective. And liquid cooling has both safety concerns and is more expensive to implement.

There is a real reason why a passive cooled BEV should exist, at least in climates where battery life is reasonable.


I agree. For different climates different solutions. In California, all Leafs should have naked battery (not covered with plastics) and
lots of air passages. That would help considerably. In Norway, no need for cooling, just heating and even thermal insulation.



About liquid cooling. Battery cells absolutely do not care the medium that is used for cooling. Be it refrigerant tube walls,
cold air or liquid glycol. Battery only cares about the temperature, in the worst possible place (so usually in the center of the cell).
If Leaf had that eNV200 cooling unit, it would help a LOT. BUT.... it would not help for those Leafs that degraded all the time at
30-35*C weather. As cooling unit mostly only works when parked (it is unreasonable to keep it running randomly when parked.

Problem with Leaf is chemistry, that does not accept 40*C in 30-35*C climate. That was the biggest mistake.
Tesla's chemistry loves 40*C. Though hates cold. So much that Tesla is CONSIDERABLY worse than Leaf, for my climate.
Not that it degrades. No. It is just heavily restricting and heat-hungry.

Re: Cabin Air Cooling the Battery

Posted: Tue Jul 31, 2018 7:47 pm
by GRA
arnis wrote:
WetEV wrote:Easy to implement, perhaps. But not very effective. And liquid cooling has both safety concerns and is more expensive to implement.

There is a real reason why a passive cooled BEV should exist, at least in climates where battery life is reasonable.


I agree. For different climates different solutions. In California, all Leafs should have naked battery (not covered with plastics) and
lots of air passages. That would help considerably. In Norway, no need for cooling, just heating and even thermal insulation <snip>.

No. In California most LEAFs need active cooling. You might want to check summer temps here, including this past week's. Here's an example of some July records in SoCal:
All-time high temperature records set throughout Southern California, including Los Angeles
https://www.washingtonpost.com/news/capital-weather-gang/wp/2018/07/06/monster-heat-dome-threatens-all-time-high-temperature-records-in-southern-california-friday/?noredirect=on&utm_term=.8eed91e8b44c

Triple digit (100+ deg. F.) highs are common throughout the Central Valley and in various other areas of the state in summer, including most of the major metro areas. I live in one of the more moderate Bay Area microclimates ('70s F. this week), but I only need to go 10 miles east to see 90s and 100s (32 - 38C+) on a regular basis in summer. The large wildfires burning in the Redding area and in Lake County now are all being made worse by triple digit temps, with the lows only falling into the '70s (22-28C) at night:
Nearly 2 weeks of 100-plus heat bakes Redding: Everything becoming 'susceptible to burning'
https://www.sfgate.com/weather/article/Carr-Fire-Redding-weather-heat-record-high-temp-13111435.php

Hottest temp I've ever experienced here was 114F (45.5C) in Red Bluff (central valley, 30 miles south of Redding), but I've seen 111 in parts of the Bay Area. Some cities in desert areas were hitting 119 (48C) this past week, and Death Valley held the world record for some years at 134 (56.7C).

Re: Cabin Air Cooling the Battery

Posted: Wed Aug 01, 2018 6:50 am
by arnis
GRA wrote:No. In California most LEAFs need active cooling. ..
Triple digit (100+ deg. F.) highs are common throughout the Central Valley and in various other areas of the state in summer, including most of the major metro areas.


What's wrong with triple digits and air cooling? Tesla tries to warm up the pack to 104F.
The reason LEAF pack fails is not lack of cooling, it is lack of temperature tolerance.
As soon as vehicle is switched off (which is 95% of 24h, except charging, applies to plugin vehicles) cooling
system will be deactivated. So if parked outside in 105*F, battery will reach that really really fast.

PS: It's been extremely hot in Europe lately. Here (Scandinavian corner) we have 28-32*C pretty much every day.
This is extraordinary, but I don't mind :D
Leaf's pack is hovering between 33-39*C.

Re: Cabin Air Cooling the Battery

Posted: Wed Aug 01, 2018 7:10 am
by WetEV
GRA wrote:No. In California most LEAFs need active cooling.


Or perhaps different battery chemistry for hotter places. The problem with one size fits all is that it doesn't.

Re: Cabin Air Cooling the Battery

Posted: Wed Aug 01, 2018 8:51 am
by arnis
WetEV wrote:
GRA wrote:No. In California most LEAFs need active cooling.


Or perhaps different battery chemistry for hotter places. The problem with one size fits all is that it doesn't.


Exactly. BTW, Tesla's chemistry is NOT good in cold climates where I live (or Norway).
It is not acceptable that battery can not charge (at all) below 0*C. Nonsense. It's not like it has water for electrolyte :|

Schrödinger's Leaf has a chemistry that fits everybody. And doesn't.

Re: Cabin Air Cooling the Battery

Posted: Wed Aug 01, 2018 12:46 pm
by goldbrick
arnis wrote:Schrödinger's Leaf has a chemistry that fits everybody. And doesn't.


Of course the problem is you can't tell which it is until you buy it to find out. Maybe if it was just leased the answer could remain uncertain and then you wouldn't have to worry about it.