基于无线电能传输的锂离子电池交直流复合加热方法研究

The development of electric vehicles is China’s national strategy and a strong support for achieving the carbon peaking and carbon neutrality goals. Lithium-ion battery is an important energy source for electric vehicles, and its low-temperature charging and discharging characteristics directly lead to the dilemma that electric vehicles fail to start and exhibit severe range degradation. This study focuses on the rapid heating of lithium-ion batteries at low temperature: A DC-AC hybrid heating system based on wireless energy transmission topology is designed. The efficient switching between AC heating and pulse self-heating is realized based on the heat generation characteristics of the battery. The heat generation characteristics of AC heating and DC heating methods under different initial conditions were studied. The influence of different heating parameters such as effective value of heating current, initial power, switching frequency and duty cycle on heating effect and the influence of different heating methods on battery life were clarified. Based on the fuzzy control theory, the AC and DC compound heating strategy is established. The test results show that the power consumption from −20 °C to 0 °C is less than 5%, the temperature rise rate is more than 3 °C/min, and the battery capacity degradation of 200 times heating is less than 2.37%.