BATTERY BASICS
How do these portable power sources store and release electricity?
WORDS LAURA MEARS
DID YOU KNOW? You can charge your phone between 200 and 300 times before its battery capacity starts to drop
Batteries are pocket reactors. They generate electricity using chemicals that release currents of electrons. These subatomic particles have a negative charge. When they travel from place to place, they take that charge with them, providing the energy to power our devices. Batteries work because of three basic principles: first, that electrons in metals can move around. Second, that particles with positive or negative charges can move freely when they dissolve in liquids like water. And third, that when you put two different metals together with a liquid containing charged particles, one metal can take electrons from the other.
It took humanity thousands of years to put these principles together to create batteries as we know them. But our ancestors did manage to create something like a battery long before the science of electricity really took off. In fact, the very first example predates the Colosseum. Known as a Parthian galvanic cell or a Baghdad Battery, it was about the size of a football. On the outside it looked like a normal clay pot, but inside it held an iron rod, a copper cylinder and an acid like vinegar or wine. Acids contain dissolved ions, allowing the iron and the copper to exchange electrons. Science historians think that these ancient batteries would only have been able to generate a very small voltage. But these early cells laid the foundations for a revolution thousands of years in the future.