In a battery heating system an inverter includes a first-phase bridge arm, a second-phase bridge arm and a third-phase bridge arm connected in parallel, each of a upper bridge arm and a lower bridge arm is provided with a switch module, the switch module is connected in parallel with a buffer module; and a motor controller in the inverter is provided for providing driving signals to the switch module of a target upper bridge arm and the switch module of a target lower bridge arm to control the switch module of the upper bridge arm of any bridge arm among the three phases of bridge arms and the switch module of the lower bridge arm of at least one bridge arm among the bridge arms except the bridge arm where the switch module of the target upper bridge arm is located to be periodically turned on and off.