I'm confused about storing Litium Ion batteries

[Philippine Mango]

http://www.batteryuniversity.com/parttwo-34.htm

I hear that you're not suppose to freeze Li-on batteries yet they show in the graph the slowed rate of reduced capacity at 0C. What *is the best* temp to store the batteries at? I was thinking of storing them in my fridge.

http://en.wikipedia.org/wiki/Lithium_ion_battery#_note-0

0 °C (32 °F)
40% Charge
2% loss after 1 year
100% Charge
6% loss after 1 year

I'm not completely sure about the info on wikipedia.

 

[Lord Evermore]

According to Dan, the freezing point of Lithium-Ion electrolyte is under -20C, and they'll work at much lower capacity down to that point.

Oxidation is a chemical reaction, so it makes sense that it slows down at lower temperatures. Note however that according to that graph, storing them with a 40% charge instead of 100% makes a huge difference as well, considering that a 40% charge keeps the capacity up very high no matter the temperature.

You could e-mail Dan for what can be considered a "definitive expert opinion". He pretty much knows everything, and maybe you'll get your email published on his site. He might even find things on the batteryuniversity site to debunk with hilarity.

At any rate, storing them in your fridge will get them down to about 35 to 40F, which is between 1.5 and 4.5C. The freezer would be a few degrees below 0C but nowhere near enough to damage the battery, but also probably not a significant difference in battery life.

 

[corkyg]

Standard practice in the military has been for years to store batteries in a refrigerator - not a freezer. It just keeps them fresher. But, look at stores - they are on the shelf at room temp. No problems.

The problems with lithium batteries is disposing of them after they are morte. They are supposed to be treated as hazmat.

 

[Lord Evermore]

Well as Dan points out, lithium-ion batteries that have been sitting on a store shelf for a year have lost a year's worth of lifespan when they'll only last 2 to 3 years at best anyway. Not that many lithium-ion batteries sit on store shelves, but they can sit at the warehouse for a parts dealer for awhile, and may well be sitting in a very warm environment, at who knows what charge level.

 

[JimPhelpsMI]

Hi, Don't freeze any rechargable battery. Just put them in the refrigerator where it's about 40 degrees F. Self discharge increases with temperature. Keeping them cool reduces the self discharge. They still go down only not quite as fast. Works with any battery.

Good Luck, Jim