CROSS-REFERENCE TO RELATED APPLICATION

The present application is a National Stage of International Application No. PCT/CN2019/072663 filed on Jan. 22, 2019, which claims priority to Chinese Patent Application No. 201822274044.X, filed on Dec. 29, 2018 and entitled “BATTERY HEATING SYSTEM”, which is incorporated herein by reference in its entirety.

TECHNICAL FIELD

The disclosure relates to the field of battery power, in particular to a battery heating system.

BACKGROUND

With development of new energies, these new energies are used in more and more fields as power. Due to advantages of high energy density, recyclable charging, safety and environmental protection, batteries are widely used in fields such as new energy vehicles, consumer electronics and energy storage systems.

However, utilization of a battery in a lower-temperature environments is subject to certain restrictions. Specifically, discharge capacity of the battery in a lower-temperature environment may be severely degraded, and the battery may not be charged in a lower-temperature environment. Therefore, it is necessary to heat the battery in a lower-temperature environment in order for normal utilization of the battery.

At present, the battery can be heated by equipping the battery with a special thermal circulation container and indirectly heating heat-conducting material in the thermal circulation container to conduct heat to the battery. However, this heating method takes a long time and has lower heating efficiency.

SUMMARY

The embodiments of the disclosure provides a battery heating system, which can improve heating efficiency of a battery pack and enhance safety of the battery heating system.

The disclosure provides a battery heating system, including a switch assembly connected to a battery pack, an inverter connected to the switch assembly, and a motor connected to the inverter; the inverter comprises a first-phase bridge arm, a second-phase bridge arm and a third-phase bridge arm connected in parallel, wherein each of the first-phase bridge arm, the second-phase bridge arm and the third-phase bridge arm includes an upper bridge arm and a lower bridge arm, the upper bridge arm is provided with a switch module, the lower bridge arm is provided with a switch module, the switch module is connected in parallel with a buffer module, and the buffer module is configured to protect the switch module; a first-phase input terminal, a second-phase input terminal and a third-phase input terminal of the motor are connected respectively to a connection point of the upper bridge arm and the lower bridge arm in the first-phase bridge arm, a connection point of the upper bridge arm and the lower bridge arm in the second-phrase bridge arm and a connection point of the upper bridge arm and the lower bridge arm in the third-phase bridge arm; and the inverter further comprises a motor controller for outputting 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 target upper bridge arm and the switch module of the target lower bridge arm to be periodically turned on and off so as to generate an alternating current, wherein the switch module of the target upper bridge arm is the switch module of the upper bridge arm of any bridge arm among the first-phase bridge arm, the second-phase bridge arm and the third-phase bridge arm, and the switch module of the target lower bridge arm is the switch module of the lower bridge arm of at least one of the bridge arms except the bridge arm where the switch module of the target upper bridge arm is located.

The disclosure provides a battery heating system, in which the motor controller outputs driving signals to the switch module of the target upper bridge arm and the switch module of the target lower bridge arm to control the switch module of the target upper bridge arm and the switch module of the target lower bridge arm to be periodically turned on and off, such that an alternating current is generated in a circuit formed by the battery pack, the main positive switch, the switch module of the target upper bridge arm, the motor, the switch module of the target lower bridge arm and the main negative switch, that is, the battery pack is alternately charged and discharged. In the process of alternate charging and discharging of the battery pack, since there is an internal resistance in the battery pack, it will generates heat, that is, heat is generated internally in the battery pack, thereby improving heating efficiency of the battery pack. In addition to improvement of heating efficiency of the battery pack, the buffer module can absorb electric energy, which prevents a sudden change in the alternating current generated by the battery heating system (such as a spike voltage or the like) from damaging the battery heating system, and thereby enhancing safety of the battery heating system.

