A Novel Technical Approach for Battery Self-Heating in Electric Vehicles based on Inherent Resonance

The application of low temperature heating to lithium-ion batteries represents an effective strategy for mitigating performance degradation. In this digest, the overall architecture of electric vehicles is considered, wherein a multi-period offset-square-wave injection (MPOSWI) method is proposed. By injecting direct current and high-frequency voltage into the d-axis of the motor, a bipolar alternating current is induced in battery bus, resulting in Joule heating to achieve battery self-heating. The proposed method utilizes the existing hardware structure of the original electric drive system and incorporates an injection signal into the basic vector control, offering a straightforward implementation approach suitable for all electric vehicles equipped with electric drive systems. A comprehensive analysis of the principle whereby injecting high frequency results in the generation of alternating current in the DC bus is provided. Meanwhile, preliminary experimental results are derived by using drive system and battery pack verifies the effectiveness of the proposed method.