BATTERY, BATTERY MODULE, BATTERY PACK, AND ELECTRIC VEHICLE

A battery, a battery module, a battery pack, and an electric vehicle are provided. The battery includes a metal shell and a plurality of electrode core assemblies sealed in the metal shell and arranged in sequence. The electrode core assemblies are connected in series. Each of the electrode core assemblies includes at least one electrode core. The electrode core assemblies are sealed in a packaging film. An air pressure between the metal shell and the packaging film is lower than an air pressure outside the metal shell. An air pressure inside the packaging film is lower than the air pressure between the metal shell and the packaging film.