Freezing a battery can slow the natural, self discharge rate of the battery, thus prolonging its life. Although the effects are minimal on alkaline batteries, NiMh and NiCd batteries can retain up to 90 per cent of their charge after being stored for a month in a freezer. In addition to helping retain the life of the batteries, freezing a rechargeable battery can help restore its life. Dead rechargeable cells may be rejuvenated through the extreme temperatures that freezing produces. Once the battery is brought back to room temperature, the cells may effectively charge again.
Inspect the battery. Look for signs of leaking, corrosion and large dents. If any of these are noticed, do not attempt to freeze the battery. The battery should be discarded immediately.
Place the battery in a sealable plastic bag or container. Not only does this protect the battery from any possible water damage, it also protects food stored in the freezer in case of a battery leak or explosion.
Place the battery in the freezer. When storing the battery for prolonged periods of time, rechargeable batteries should be removed and recharged once every 3-6 months to help maintain the life of the battery.
Remove the batteries from the freezer the day before you wish to use them. Allow them to heat back to room temperature before using or charging them. Do not attempt to reheat the batteries using a heater, oven, microwave or other heating agent. They should naturally be brought to room temperature.