The internal structure of LiFePO4 battery: LiFePO4 with olivine structure on the left is used as the positive electrode of the battery. The aluminum foil is connected with the positive electrode of the battery. The middle is the separator of the polymer. It separates the positive electrode from the negative electrode, but the lithium ion Li+ can pass and the electron e- Can not pass, the right side is a battery negative electrode composed of carbon (graphite), connected by copper foil to the negative electrode of the battery. Between the upper and lower ends of the battery is the electrolyte of the battery, and the battery is hermetically sealed by a metal casing.