cwerdna
Gold Member
Posts: 7260
Joined: Fri Jun 03, 2011 4:31 pm
Delivery Date: 28 Jul 2013
Location: SF Bay Area, CA

Re: Battery temp management for new leaf

Sun Oct 08, 2017 12:08 am

Regarding density and size, http://nissannews.com/en-US/nissan/usa/ ... issan-leaf says
The new battery design adds energy-storage capacity without increasing the size. The battery pack occupies the exact same dimensions as that of the previous-generation LEAF. The individual cell structure of the laminated lithium-ion battery cells has been improved, representing a 67 percent increase in energy density versus the original 2010 LEAF model.

'13 blue Leaf SV w/premium package (owned)
'13 blue Leaf SV w/QC + LED & premium packages (lease over, car returned)
'06 Prius

DaveinOlyWA
Posts: 12328
Joined: Sat Apr 24, 2010 7:43 pm
Delivery Date: 10 Nov 2016
Leaf Number: 314199
Location: Olympia, WA
Contact: Website

Re: Battery temp management for new leaf

Sun Oct 08, 2017 6:50 am

cwerdna wrote:Regarding density and size, http://nissannews.com/en-US/nissan/usa/ ... issan-leaf says
The new battery design adds energy-storage capacity without increasing the size. The battery pack occupies the exact same dimensions as that of the previous-generation LEAF. The individual cell structure of the laminated lithium-ion battery cells has been improved, representing a 67 percent increase in energy density versus the original 2010 LEAF model.


your information is obvious and implied but that does not work for everyone.
2011 SL; 44,598 miles. 2013 S; 44,840 miles.2016 S30 (build 10/2016)"low water marks" 27,000 miles.363GID Ahr 79.13Hx95.17%kwh28.1QCs238,L2's 251
My Blog; http://daveinolywa.blogspot.com" onclick="window.open(this.href);return false;

SageBrush
Posts: 1495
Joined: Sun Mar 06, 2011 2:28 am
Delivery Date: 13 Feb 2017
Location: Colorado

Re: Battery temp management for new leaf

Sun Oct 08, 2017 7:28 am

cwerdna wrote:Regarding density and size, http://nissannews.com/en-US/nissan/usa/ ... issan-leaf says
The new battery design adds energy-storage capacity without increasing the size. The battery pack occupies the exact same dimensions as that of the previous-generation LEAF. The individual cell structure of the laminated lithium-ion battery cells has been improved, representing a 67 percent increase in energy density versus the original 2010 LEAF model.

I wonder what 'individual cell structure' means.
Sounds like packaging rather than chemistry, but I am not sure.

Since the pack dimensions are the same and that dictates the heat loss rate, I'll surmise that the 40 kWh pack will have the same degradation problems as the earlier generations.
2013 Model 'S' with QC & rear-view camera
Bought off-lease Jan 2017 from N. California with 63.9 Ahr after 22k miles
Car is now enjoying an easy life in Colorado

DaveinOlyWA
Posts: 12328
Joined: Sat Apr 24, 2010 7:43 pm
Delivery Date: 10 Nov 2016
Leaf Number: 314199
Location: Olympia, WA
Contact: Website

Re: Battery temp management for new leaf

Sun Oct 08, 2017 7:31 am

SageBrush wrote:
cwerdna wrote:Regarding density and size, http://nissannews.com/en-US/nissan/usa/ ... issan-leaf says
The new battery design adds energy-storage capacity without increasing the size. The battery pack occupies the exact same dimensions as that of the previous-generation LEAF. The individual cell structure of the laminated lithium-ion battery cells has been improved, representing a 67 percent increase in energy density versus the original 2010 LEAF model.

I wonder what 'individual cell structure' means.
Sounds like packaging rather than chemistry, but I am not sure.

Since the pack dimensions are the same and that dictates the heat loss rate, I'll surmise that the 40 kWh pack will have the same degradation problems as the earlier generations.


why should you "surmise" when I have to provide proof of every little statement I make no matter how intuitive the statement is?
2011 SL; 44,598 miles. 2013 S; 44,840 miles.2016 S30 (build 10/2016)"low water marks" 27,000 miles.363GID Ahr 79.13Hx95.17%kwh28.1QCs238,L2's 251
My Blog; http://daveinolywa.blogspot.com" onclick="window.open(this.href);return false;

Dooglas
Posts: 176
Joined: Thu Apr 03, 2014 10:08 pm
Delivery Date: 04 Jan 2017
Leaf Number: 314779
Location: Oregon City, OR

Re: Battery temp management for new leaf

Sun Oct 08, 2017 9:56 am

SageBrush wrote:Since the pack dimensions are the same and that dictates the heat loss rate, I'll surmise that the 40 kWh pack will have the same degradation problems as the earlier generations.

Number 1 - Heat loss rate is NOT simply a result of pack dimensions. The pack is not solid. Number 2 - The 24 kwh lizard battery does not have the same degradation rate as the 2011/12 24 kwh battery. There is no basis for your conclusion (prediction?) that the 40 kwh pack will have the same degradation rate as any one of the previous generation packs. This discussion has become long on undocumented assumptions and guestimates that are more belief than conclusion. I'd say it is time to put the thread out of its misery.
2013 Leaf SV - lease ended, 2016 Leaf S30

SageBrush
Posts: 1495
Joined: Sun Mar 06, 2011 2:28 am
Delivery Date: 13 Feb 2017
Location: Colorado

Re: Battery temp management for new leaf

Sun Oct 08, 2017 10:08 am

Dooglas wrote:
SageBrush wrote:Since the pack dimensions are the same and that dictates the heat loss rate, I'll surmise that the 40 kWh pack will have the same degradation problems as the earlier generations.

Number 1 - Heat loss rate is NOT simply a result of pack dimensions. The pack is not solid.

This has nothing to do with being solid or not, it has to do with surface area for passive heat dissipation. The other parameters in play are the temperature gradient, heat generation, and the case material. Since no mention was made of changes to the pack casing, the power to move the car stays about the same, and we do not control ambient temperatures, the surface area becomes the difference. Same pack, same surface area.
2013 Model 'S' with QC & rear-view camera
Bought off-lease Jan 2017 from N. California with 63.9 Ahr after 22k miles
Car is now enjoying an easy life in Colorado

johnlocke
Posts: 178
Joined: Fri Jan 08, 2016 3:47 pm
Delivery Date: 14 Dec 2015
Leaf Number: 300582

Re: Battery temp management for new leaf

Sun Oct 08, 2017 10:51 am

SageBrush wrote:
Dooglas wrote:
SageBrush wrote:Since the pack dimensions are the same and that dictates the heat loss rate, I'll surmise that the 40 kWh pack will have the same degradation problems as the earlier generations.

Number 1 - Heat loss rate is NOT simply a result of pack dimensions. The pack is not solid.

This has nothing to do with being solid or not, it has to do with surface area for passive heat dissipation. The other parameters in play are the temperature gradient, heat generation, and the case material. Since no mention was made of changes to the pack casing, the power to move the car stays about the same, and we do not control ambient temperatures, the surface area becomes the difference. Same pack, same surface area.

Same dimensions but higher energy density. 40KWH vs 30KWH or 24KWH. Not a huge effect while driving (lots of airflow around the battery) but a substantial difference while charging (longer charge time and no airflow to dissipate heat buildup). Unless you intentionally limit the battery capacity (I.E. 12% to 88%) there will be more heat buildup due to a longer charge time. Plus the fact that you are likely to charge it to 100% from a low state(30% or less). This likely to really problematic if you are DCFC'ing on a trip. With the 30KWH battery, adding 2 temp bars during fast charging is common. I expect it to be worse with 40KWH battery. Add in the heating effect from high discharge rates from freeway driving and long trips encouraged by the longer range battery and you could have a recipe for a disaster.
2016 SV
Jamul, CA
San Diego East County

Dooglas
Posts: 176
Joined: Thu Apr 03, 2014 10:08 pm
Delivery Date: 04 Jan 2017
Leaf Number: 314779
Location: Oregon City, OR

Re: Battery temp management for new leaf

Sun Oct 08, 2017 12:08 pm

SageBrush wrote:This has nothing to do with being solid or not, it has to do with surface area for passive heat dissipation.

Ah, BINGO. As the pack is not a solid object, or of a uniform density for that matter - the spaces inside the pack, the density of the individual cells, and any number of other factors are also relevant to how the pack passively dissipates heat.
2013 Leaf SV - lease ended, 2016 Leaf S30

WetEV
Posts: 1784
Joined: Fri May 04, 2012 8:25 am
Delivery Date: 16 Feb 2014
Location: Near Seattle, WA

Re: Battery temp management for new leaf

Sun Oct 08, 2017 2:09 pm

SageBrush wrote:The other parameters in play are the temperature gradient, heat generation, and the case material.


So what about pack chemistry? Does that have anything at all to do with lifetime?
WetEV
#49
Most everything around here is wet during the rainy season. And the rainy season is long.
2012 Leaf SL Red (Totaled)
2014 Leaf SL Red

lorenfb
Posts: 1406
Joined: Tue Dec 17, 2013 10:53 pm
Delivery Date: 22 Nov 2013
Leaf Number: 416635
Location: SoCal

Re: Battery temp management for new leaf

Sun Oct 08, 2017 2:16 pm

Dooglas wrote:
SageBrush wrote:This has nothing to do with being solid or not, it has to do with surface area for passive heat dissipation.

Ah, BINGO. As the pack is not a solid object, or of a uniform density for that matter - the spaces inside the pack, the density of the individual cells, and any number of other factors are also relevant to how the pack passively dissipates heat.


Or how "the pack" passively absorbs heat (chassis/ambient), i.e. its effective thermal resistance to the
chassis and ambient - both paths are in parallel. Like parallel resistors, one path may dominate,
i.e. the much lower thermal resistance.

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