Abstract: A battery self-heating device includes a battery self-heating circuit and a controller. The battery self-heating circuit includes a first battery group, a second battery group, a bridge arm, and a winding corresponding to the bridge arm. A negative electrode of the first battery group and a positive electrode of the second battery group are connected to each other, and are connected to an output end of the winding. An input end of the winding is connected to a midpoint of the bridge arm. A positive electrode of the first battery group is connected to a first bus end of the bridge arm. A negative electrode of the second battery group is connected to a second bus end of the bridge arm. The controller is configured to adjust the duty ratio of the bridge arm according to a target duty ratio range.

Abstract: A battery self-heating control method includes: in a first period of each of control periods, configuring a conduction state of an upper bridge arm assembly and a conduction state of a lower bridge arm assembly to be a self-heating state, and in the self-heating state, alternately charging and discharging a first battery pack and/or a second battery pack to heat the battery pack by a current on a second connecting wire between a motor and the battery pack.

Abstract: A battery heating system includes: a power battery pack including a first battery assembly and a second battery assembly connected to each other at a connection point, buck-boost inverters connected in parallel to form a first bus terminal and a second bus terminal, and a controller connected to a control terminal of the inverter bridge and configured to control self-heating of the first battery assembly and the second battery assembly. A center line is led out at the connection point. Each buck-boost inverters includes an inverter bridge and an inductor. The first bus terminal is connected to a positive electrode of the power battery pack. The second bus terminal is connected to a negative electrode of the power battery pack. A first terminal of the inductor is connected to a midpoint of the inverter bridge. A second terminal of the inductor is connected to the center line.