Uninterruptible power supply auxiliary power supply method for energy storage system

The invention discloses an uninterruptible power supply auxiliary power supply method for an energy storage system, and relates to the technical field of energy storage batteries. When the energy storage system is in a running state, firstly, whether input alternating current exists or not is monitored, if yes, a contact of a circuit breaker Q1 is disconnected, the alternating current of a power grid is supplied to a UPS host, and the UPS host is used for charging a UPS battery; when the power grid is always electrified, the circuit breaker Q1 is always switched off, and the UPS battery is charged by the power grid; when the energy storage system is in a non-running state, firstly, whether alternating current exists or not is monitored, if yes, a circuit breaker Q1 is manually switched on, and photovoltaic power generation is used for supplying power to a solar controller; and when the alternating current input is suddenly detected to be electrified, the circuit breaker Q1 is immediately switched off, and the