Batteries are a kind of energy conversion and storage device, which converts chemical energy or physical energy into electrical energy through reaction. According to the different energy conversion, the battery can be divided into chemical battery and physical battery.

Chemical battery or chemical power supply is a device that converts chemical energy into electrical energy. It is composed of two kinds of electrochemical active electrodes with different components, which are used as electrolyte. When connected to an external carrier, it can provide electric energy by converting its internal chemical energy.

Physical battery is a device that converts physical energy into electrical energy.