A circuit breaker refers to a mechanical switching device that can connect, carry, and break the current under normal circuit conditions, as well as connect, carry a certain amount of time and break the current under specified abnormal circuit conditions. It has the function of short circuit/overload protection. In energy storage systems, circuit breakers are mainly used to detect and protect electrical equipment from overload, short circuit, and other fault conditions. According to their different application scenarios and functions, circuit breakers can be divided into the following types:

1. Air circuit breaker: mainly used in low-voltage circuits, it can quickly cut off the circuit and protect electrical equipment and personnel safety in the event of electrical faults.

2. Micro circuit breaker: Commonly used in low-voltage circuits in homes and commercial buildings to protect circuits from short circuits and overloads, it is a common low-voltage protection device.

3. Circuit breaker switch: can be used in medium and high voltage circuits to cut off circuits and provide protection, usually used in industrial and power systems.

4. DC circuit breaker: mainly used in DC circuits, such as solar photovoltaic systems, electric vehicle charging systems, etc., to cut off and protect DC circuits.

5. Isolation switch: usually used to disconnect circuits, not for overload or short circuit protection, to ensure safe operation of electrical equipment during maintenance and repair.

The functions of circuit breakers include the following aspects:

1. Overload protection: capable of detecting and cutting off overload current to prevent equipment damage due to current overload.

2. Short circuit protection: It can quickly cut off the circuit and protect the equipment from the impact of short circuit faults.

3. Personal safety: It can protect personnel from electrical shock hazards and ensure the safety of electrical equipment and personnel.

4. Equipment protection: It can protect the equipment and components in the circuit from the influence of abnormal currents and voltages, extending the service life of the equipment.

The circuit breaker in the energy storage system plays an important protective role, ensuring the safe and stable operation of the system, preventing faults and accidents, and protecting the safety of equipment and personnel. Different types of circuit breakers have different functions and protection characteristics according to their application scenarios and circuit characteristics.