Battery self-heating device and method and electric vehicle

The invention relates to a battery self-heating device and method and an electric vehicle, the battery self-heating device comprises a first control switch, a second control switch, a bridgeless PFC circuit and a controller, the controller is configured to control the first control switch and the second control switch to be switched on in a preset battery self-heating state, and the bridgeless PFC circuit is configured to control the bridgeless PFC circuit to be switched off in the preset battery self-heating state. And the bridgeless PFC circuit and the power battery are charged or discharged by controlling the on-off of a switching tube in the bridgeless PFC circuit, so that the self-heating of the power battery is realized. Thus, under the condition that the electric vehicle is not in a charging state, charging and discharging between the electric vehicle and the power battery can be achieved at any time through the bridgeless PFC circuit, self-heating of the power battery is achieved on the premise that e