A storage device that converts chemical energy into electrical energy. Used by the billions each year from tiny hearing aid batteries to units that some day may be 40 feet long (see illustration below), the battery is constructed of positive and negative metal electrodes. When the two electrodes are connected together by a circuit on the outside, a chemical reaction is created inside, and electrons flow from the negative electrode through an electrolyte to the positive electrode creating a voltage difference. The electrolyte material prevents the electrons from flowing until the circuit is completed on the outside.
The First Battery
Alessandro Volta invented the first battery in 1800 to sustain an electric current. His "voltaic pile" was a stack of cells, each containing a brine-soaked cloth sandwiched between zinc and copper discs. He got the idea from Luigi Galvani, who in the late 1700s generated current from two dissimilar metals joined together by a frog's muscle. Over time, there has been progress! See batteries
The Liquid Metal Battery
This battery technology uses molten metals and was invented for the U.S. electrical grid, but all batteries work the same. When the electrodes are connected to a load on the outside (light bulb, electronic circuit, electrical grid, etc.), electrons flow from the negative electrode to the positive electrode through the electrolyte. See liquid metal battery