Battery Pack Climate Management

[blatt]

Hello LEAF-enthusiasts!

Does anyboone know more about how the battery heat is controlled?

Am I right to asume, that the air inlet is in the passenger cabin to use the cabin a/c and the outlet is somewhere under the car? So it would help the battery to have the a/c switched on rather than trying to save energy by keeping it off?

Does anyone know where the battery-cooling air is let out? I am interested in meassuring its temperature.

Thank you!

blatt

 

[surfingslovak]

Does anyboone know more about how the battery heat is controlled?

Hi blatt, the pack is sealed in a steel container and it does not have any active heat management. Not even a fan. If I recall correctly, there is a breather valve to let air out of the pack, but that's about it. I tried to find a reference to prior posts for you, but the search on this forum is somewhat challenged as of this writing.

 

[blatt]

surfingslovak! Thank you!

After all I also found that kind of quite shoking information in another thread: http://www.mynissanleaf.com/viewtopic.php?f=27&t=5331&p=125937&hilit=passive+battery+cooling#p125937" onclick="window.open(this.href);return false;

 

[SnaxMuppet]

Nissan have announced that the model year 2012 will have active battery management but it sounds like it is only going to be active at temperature extremes... useful in hot or cold locations but for most people not much benefit.

 

[Herm]

Nissan have announced that the model year 2012 will have active battery management but it sounds like it is only going to be active at temperature extremes... useful in hot or cold locations but for most people not much benefit.

Only active in very cold conditions, an electric resistance heater IN the battery comes on at -4°F, there is nothing for hot extremes besides shutting down the car.

 

[blatt]

Only active in very cold conditions, an electric resistance heater IN the battery comes on at -4°F, there is nothing for hot extremes besides shutting down the car.

Herm,

Thank you! Do you have any reference for the given information? Is ist from the manual?

thx ;-)

 

[TomT]

Actually, the battery pack is completely sealed and is at slight positive pressure inside. The cold weather package simply includes a resistance heater internal to the pack that goes on at something like -14 degrees Fahrenheit and off at -4 (I don't recall the exact values from the Service Manual off the top of my head), controlled by a pack internal thermostat. Other than that, it is at the mercy of the ambient conditions. It does have appreciable thermal mass, however, so any internal temperature changes brought about from the ambient outside influence will take place slowly...

Does anyboone know more about how the battery heat is controlled?

Hi blatt, the pack is sealed in a steel container and it does not have any active heat management. Not even a fan. If I recall correctly, there is a breather valve to let air out of the pack, but that's about it. I tried to find a reference to prior posts for you, but the search on this forum is somewhat challenged as of this writing.

 

[DarkStar]

Actually, the battery pack is completely sealed and is at slight positive pressure inside. The cold weather package simply includes a resistance heater internal to the pack that goes on at something like -14 degrees Fahrenheit and off at -4 (I don't recall the exact values from the Service Manual off the top of my head), controlled by a pack internal thermostat. Other than that, it is at the mercy of the ambient conditions. It does have appreciable thermal mass, however, so any internal temperature changes brought about from the ambient outside influence will take place slowly...

+1 for what TomT said. I'll just add that these types of batteries have a typical operational temperature of about -4 F to around 90 F.

 

[Herm]

usually up to 122°F and you start running away at 135°F

 

[mechkid]

more or less when i do get my nissan leaf i would do major hacks to it's system's and componets so i can get even more out of my nissan leaf without paying for the crummy manufactured stuff like for example a battery without a fan is like a laptop without a cooling pad!!!!!!!!!!

 

[EVDRIVER]

more or less when i do get my nissan leaf i would do major hacks to it's system's and componets so i can get even more out of my nissan leaf without paying for the crummy manufactured stuff like for example a battery without a fan is like a laptop without a cooling pad!!!!!!!!!!

What hacks do you intend to consider?

 

[Herm]

He could drill some holes in the battery case and duct some cold air from the AC into it, thats major hacking.

 

[TomT]

That is basically how the Coda thermal management system works. It is a completely separate closed loop air system that can either heat or cool the air, which is then passed internally down the center of the pack between the cells and loops around the two outsides of the cells, and then back to the pack air handler.

He could drill some holes in the battery case and duct some cold air from the AC into it, thats major hacking.

 

[Herm]

In the Coda, is the chiller internal to the battery pack or they duct cold air into the pack?

 

[TomT]

The heater/chiller is external to the pack and ducted in.

In the Coda, is the chiller internal to the battery pack or they duct cold air into the pack?

 

[AndyH]

Hello LEAF-enthusiasts!

Does anyboone know more about how the battery heat is controlled?

Am I right to asume, that the air inlet is in the passenger cabin to use the cabin a/c and the outlet is somewhere under the car? So it would help the battery to have the a/c switched on rather than trying to save energy by keeping it off?

Does anyone know where the battery-cooling air is let out? I am interested in meassuring its temperature.

Thank you!

blatt

FYI blatt. Welcome aboard!
http://www.mynissanleaf.com/viewtopic.php?f=8&t=120

Battery heat control starts with the cell chemistry and laminated design - we don't need a battery cooling system if we don't make heat. As already mentioned, the 2012 Leaf has a battery heater for extremely cold temperatures (check Nissan's Leaf page for standard features, or scan the battery forum for earlier messages).

Since the Leaf is using a very safe and stable battery chemistry, there is no metallic lithium inside to burn, and there is absolutely no thermal runaway (like laptop or Tesla Roadster cells). At extremely high temperatures - well above anything we'll see in operation - the electrolyte will break down. If severely overheated, cells will die but they won't damage the rest of the car.

The battery box has four temperature sensors inside. The computer uses the temp data for charging, discharging, state of charge adjustment, and to drive the temperature gauge on the left side of the instrument panel. Folks are working on the data network but I don't know if they've isolated the battery temperature code yet.

edit... To put numbers on this, standard lithium electrolyte is good to 60° C (140° F), with some electrolytes good to higher temps. The Nissan engineers doing hot-weather testing in the summer in Phoenix said the battery temperature only rose 1-3 degrees above ambient. Assuming those temps were in Celsius (worst case), then the battery temp only ran 46° C on a 110°F (43° C) day.

 

[TonyWilliams]

I noticed today that the battery that Nissan has on display at the "Electric Tour" in San Diego must be an earlier prototype. The front of the battery, where the High DC voltage connects to the inverters (DC/AC and DC/DC), the plugs are different. Also, I could only find 3 temperature sensors; not the four on our current production cars:


The front DC connections. Note that the top cover is off the battery which is sealed with the orange strip.

Temperature sensor on the left side of the battery pack:

Temperature probe on rear of the battery pack:

Temperature probe on the right side of the battery pack, looking down:

 

[TickTock]

This looks like the same display unit as they had at the Phoenix stop. I, too, head a hard time finding the fourth temp sensor. It is on the left side near the other left sensor, but closer to the bottom of the assembly. The wire connecting to it is visible in your picture.

 

[LEAFfan]

I'll just add that these types of batteries have a typical operational temperature of about -4 F to around 90 F.

Where did you get the info that typical operating temp is only up to 90*F? If you check your temp gauge chart it will show a much higher range before it goes into the red (10th bar). When there are 7 bars, the battery pack can be 100 degrees or more and that is STILL within the normal range.

 

[LEAFfan]

usually up to 122°F and you start running away at 135°F

Actually, when the batteries reach 123 degrees, it will shut down the LEAF immediately. If you are driving, turtle appears and then it instantly shuts down. Again, the techs that tested these batteries in the AZ heat told me that.