POWER MANAGEMENT SYSTEM, MICRO-CONTROLLER UNIT, BATTERY MANAGEMENT SYSTEM, AND BATTERY

Provided in the embodiments of the present application are a power management system, an MCU, a BMS and a battery, which can satisfy the power supply requirements of the MCU, and achieve a higher reliability. The power management system comprises: a primary power supply module, which is connected to a power source, and is used for generating a first voltage according to the voltage of the power source, diagnosing the first voltage, and storing a diagnosis result of the first voltage; and a secondary power supply module, which is connected to the primary power supply module and is used for generating a second voltage according to the first voltage, wherein the second voltage is less than the first voltage, and the second voltage is an operating voltage of an MCU; and the MCU, which is connected to the primary power supply module and the secondary power supply module, and is used for reading the diagnosis result of the first voltage from the primary power supply module and determining, according to the diagnosis result of the first voltage, whether to control a BMS to enter a safe state.