Lithium-Ion batteries degrade even without use. So the battery wouldn't be as good as new anymore. But a lot of factors affect battery degradation. State of ch

Lithium-Ion batteries degrade even without use. So the battery wouldn't be as good as new anymore. But a lot of factors affect battery degradation. State of charge is probably the easiest -- make sure that the battery is not full, and make sure they don't run empty either (check the charge every couple of months or so to make sure they don't get empty). I'm not sure what charge percentage and temperature is best for storing, but around 50% to 70% and a cool, but not freezing room is probably a good idea. I'd assume that the fridge is too cold, but I don't have any data to back that up.