ENERGY STORAGE DEVICE

The present disclosure discloses an energy storage device (100), including a battery pack (10), a waterproof plug (20), and a water immersion detection unit (30). The battery pack (10) includes a housing (11) and a connection terminal (12). The housing has an opening (111), and the connection terminal is disposed at the opening. The waterproof plug (20) includes an electrical connection member (21) configured to electrically connect to the connection terminal in response to the waterproof plug covering the opening, and configured to generate a first signal in response to water flowing into the opening. The water immersion detection unit (30) is configured to determine that the water flows into the opening through detecting the first signal. With the energy storage device provided by implementations of the present disclosure, by disposing the waterproof plug at an opening of the lowest battery pack and allowing the waterproof plug to generate the first signal in response to the water flowing into the opening, while utilizing the water immersion detection unit to detect the first signal to determine whether there is any water leakage at the opening, a water immersion detection at the opening is achieved, thereby effectively improving safety and reliability of the energy storage device. In addition, the waterproof plug is small in size and has a simple structure, which is beneficial for reducing production costs of the energy storage device.