blatt said:
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.