What is the theory behind battery heating? Does it allow the batteries to take a greater charge? Or does it allow the batteries to discharge more of the potential energy within the hour?
I find the theory part a little hard to answer. A battery converts chemical energy into electrical energy. I assume that a warm battery allows a more vigorous chemical reaction and that releases more energy.
A little web research gives this link: http://www.mpoweruk.com/thermal.htm
Quoting:
"Arrhenius Law tells us that the rate at which a chemical reaction proceeds, increases exponentially as temperature rises (See Battery Life). This allows more instantaneous power to be extracted from the battery at higher temperatures. "
I read this as the same power is there but the heat allows it to be used more easily.
The author goes on to say:
"At the same time higher temperatures improve electron or ion mobility reducing the cell's internal impedance and increasing its capacity."
So less energy is lost to internal resistance, so you are able to utilize more energy.
The very basic answer my dad told me many years ago is that when you heat the battery it expands, allowing more of a charge. As you race it cools, shrinking some allowing the battery to think it has more of a charge.
