Storing Batteries In The Freezer

Is it an old wives tale ? I once heard that keeping batteries in the freezer will prolong or even suspend their shelf life. Is this true ?

Is there a certain chemistry that this will work on ? NiMH, NiCD, or alkaline ?

Low temperature has a tendency to retard chemical processes. If a cell was nothing but chemical, the reasoning would be sound. However, a cell is also a physical container to seal or contain the reactive chemicals made of materials that respond to temperature. As the materials of the container warm they expand. As they cool, they contract. In extreme temperatures there is a corresponding extreme expansion or contraction. Since they are made from differing materials, constructed in a manner to act as a seal for containment of the reactive chemicals, the expansion rate of the materials are dissimilar. As a result, extreme temperatures act on the different materials making up the sealed container just like a bi-metal thermometer works. The materials expand differently and as a result cause a shape distortion in the materials. The result could be a compromised seal that can no longer insure the containment of the reactive chemicals.

Those factors could be considered in the manufacture of cells, but I wouldn't trust it to be the case unless the manufacture specifically states that they are operative in sub-freezing temperatures.

So would it be better to store them in the fridge ? Would that still prolong their shelf life ?

Data sheets from Energizer state operating temperatures down to -18degC. IIRC, freezers are -5degC. Should be alright, though YMMV. Fridge is probably safer though. One thing to remember is to keep them in a dry air-tight container. Moisture will also ruin your cells.

Charged NiMH cells self-discharge much slower when frozen. But they should be at room temp before using.

I keep all my batteries in the fridge. I think it cuts the self discharge rate of NIMH by a factor of three. I keep them in the plastic holders I get from Thomas Distributing.
I find the air inside a modern air-conditioner type refrigerator is at least as dry as the air outside the fridge.

I guess they would be okay in the freezer. I keep flashlights in the car, and it occasionally gets colder there than in the freezer.

I read somewhere it was a bad idea to fast-charge cold NiMH.
So when I take them out of the fridge, I hold them in my hand for a minute before charging. It probably doesn't do any good, but it makes me feel better.

The moisture I mentioned will more likely come from condensation. Fridge and freezer air itself, if using a modern frost-free fridge, should be pretty dry. Came back from a month away and found all the ice-cubes in the freezer had "sublimed" to little "ice-pebbles". /ubbthreads/images/graemlins/smile.gif

For NiMH from the fridge, it would be good to leave them on the desk for at least an hour before charging.

I think this one came from old carbon-zinc 'dry cells.' Modern chemistries are much better. Alkaline cells last, what, 8 years or so? (Energizer, Duracell, Rayovac) How much electricity you losing just opening the door for the batteries, not counting the annoyance of waiting for them to warm up? Lithiums won't see much of an improvement from cold storage.

Considering the cost of recharging my NiMH cells (Both electricity and cycle-life) it's not worth the hassle or waiting for them to warm up, or using food-space. I just leave them next to my Ray-o-vac PS4 and PS6 chargers.