Research on the Thermal Performance of Thick Film Heater for Electric Vehicle Battery

The life of power battery and its discharge efficiency in electric cars will be significantly reduced in a low temperature environment. Therefore, in order to ensure its working mileage and safety, heating the power battery is required. Heat pump air conditioners and PTC-based onboard heaters are usually way to heat the power battery under lower temperature so far. In low temperature environment, due to the lower heating efficiency of the heat pump air conditioner, onboard heaters are widely used in electric cars. A specific thick film heater(TFH) for electric vehicles is investigaed in this study, and its three dimensional heat tansfer analysis model is established. The heat transfer and fluid performace of the TFH is analied using a computational fluid dynamics software. The performance of TFH is measured on a test bench, and the measured data is used to validate the developed model. Using the established model, the heating efficiency of TFH is studied for different inlet temperatures and flow rates, and the influence of the fin spoiler structure on TFH heating efficiency and the heating board temperature is investigated. The result indicates that the spoiler structure has a large effect on the board heating temperature, but has little effect on the heating efficiency. An orthogonal experimental design method is used to optimize the design of the fins and water channels, and the purpose is to reduce the board heating temperature for preventing over burning. Under the 25℃ inlet temperature and 10L/min inlet flow rate, the calculation and experimental result demonstrates that, the board heating temperature is controlled within 190℃ after optimizing the structure, and the heating efficiency is higher than 95%. The optimization method for the channels and spoiler structures in this study provides a method for calculation and analysis to design TFH.