Batteries
[edit] How Batteries work?
Batteries are all over the place -- in our cars, our PCs, laptops, portable MP3 players and cell phones. A battery is essentially a can full of chemicals that produce electrons. Chemical reactions that produce electrons are called electrochemical reactions. In this article, you'll learn all about batteries -- the basic concept at work, the actual chemistry going on inside a battery, rechargeable versions, what the future holds for batteries and possible power sources that could replace them.
If you look at any battery, you'll notice that it has two terminals. One terminal is marked (+), or positive, while the other is marked (-), or negative. In an AA, C or D cell (normal flashlight batteries), the ends of the battery are the terminals. In a large car battery, there are two heavy lead posts that act as the terminals.
Electrons collect on the negative terminal of the battery. If you connect a wire between the negative and positive terminals, the electrons will flow from the negative to the positive terminal as fast as they can (and wear out the battery very quickly -- this also tends to be dangerous, especially with large batteries, so it is not something you want to be doing). Normally, you connect some type of load to the battery using the wire. The load might be something like a light bulb, a motor or an electronic circuit like a radio.
Inside the battery itself, a chemical reaction produces the electrons. The speed of electron production by this chemical reaction (the battery's internal resistance) controls how many electrons can flow between the terminals. Electrons flow from the battery into a wire, and must travel from the negative to the positive terminal for the chemical reaction to take place. That is why a battery can sit on a shelf for a year and still have plenty of power -- unless electrons are flowing from the negative to the positive terminal, the chemical reaction does not take place. Once you connect a wire, the reaction starts. The ability to harness this sort of reaction started with the voltaic pile.
Next, we'll check out how a voltaic pile works and look at other types of batteries.
[edit] Green Batteries
[edit] Batteries in the fridge or freezer
We searched on "batteries freezer" and also looked at several battery manufacturer's web sites to find the answer to this question. The search results led to a very detailed frequently asked questions (FAQ) page about AA and AAA cell batteries, as well as its related battery myths page that provided a plethora of information about batteries.
According to these sources, storing batteries in the freezer (or refrigerator) will make them last longer, but it depends on what kind of battery you're using. And in the long run, it may not be worth the hassle.
For alkaline batteries (the most common kind of household battery), putting them in the freezer will extend their shelf life by less than 5%. And cold batteries can't be used immediately -- you have to wait until they've warmed up to room temperature first. If you need those batteries for a flashlight in an emergency, this could prove problematic. When stored at room temperature, alkaline batteries retain 90% of their power, and the average shelf life of alkaline batteries is five to seven years.
For NiMH and Nicad batteries (often used for electronics), storing them in the freezer might be more practical. These kinds of batteries lose their charge after a few days when kept at room temperature. But they'll retain a 90% charge for months if you store them in the freezer. Just like alkaline batteries, you'll need to wait until they've warmed up before using them. However, this isn't a problem when you need new batteries for your digital camera or other electronic gadget.
Battery manufacturers tend to agree. Kodak says "refrigeration is not necessary, nor is it recommended" and "freezing is not recommended" for its alkaline batteries. Duracell advises: "Do not refrigerate Duracell batteries. This will not make them last longer." Both recommend storing batteries in a cool, dry place.
See also - Refrigerator and Freezer tips
