Why do some people store batteries in the freezer? Should you store batteries in the freezer? Ask Science looks into the deep freeze.
Of Cells and Batteries
To get to the truth of this important matter, it’s important that we fist have a basic understanding of what batteries are and how they work.
As I mentioned in my previous episode on capacitors, a battery is a collection of one or more cells capable of generating electricity. There are lots of different types of these cells, but they all work according to the same basic principle.
Part of the cell consists of chemicals that undergo a special reaction called an oxidation reaction, which is a reaction that causes atoms to lose electrons. (For more on oxidation reactions check out my episode on The Science of Fire).
The other part of the cell consists of a different set of chemicals that undergo what is called a reduction reaction. In reduction reactions, atoms gain electrons.
Quick and Dirty Tip:If you’re confused about which type of reaction is which, just remember the handy mnemonic: OIL RIG - Oxidation Is Loss, Reduction Is Gain.
As one part of the cell has an excess of electrons, and another part of the cell has a deficiency in electrons, the logical thing to do would be to send the extra electrons from one side of the cell to the other side. This is exactly what happens when you hook both ends of the cell up to a circuit. The excess electrons flow out of one side of the cell (called the anode) through the circuit and into the other side of the cell (called the cathode).
Over time, these chemical reactions can result in changes to the materials that make up the cathode and anode, resulting in the cell losing its ability to carry out the chemical reactions needed to produce electricity. When this happens, we say the cell (or the battery of cells) is “dead.”