Experimental and numerical study of energy and thermal management system for a hydrogen fuel cell-battery hybrid electric vehicle

The aims of this study were fourfold: firstly, develop a fuzzy logic control algorithm for enhancing overall energy efficiency of the fuel cell hybrid electric vehicle, secondly, balance the energy consumptions of the battery and fuel cell with aid of gradient descent optimization method, thirdly, use the waste heat of hydrogen vessels by controlling the fuel flow, and finally, operate two energy sources at cold and hot ambient temperatures safely and efficiently. In the current study, a fuzzy logic controller is used to keep of operate the hydrogen fuel cell and battery pack at their optimum temperatures. A detailed mathematical model is established, which includes electric vehicle dynamics, thermal behavior of battery, hydrogen fuel cell and vessel, and the efficiency model of electric motor. Furthermore, numerical simulations related to vessel temperature changes and energy consumption of the hybrid electric vehicle under actual road conditions are validated by experiments. The results demonstrate that total energy consumption including the propulsion system, thermal management system, and fuel supply system is decreased by 9,1% at 18 °C thanks to the fuzzy logic control algorithm. Besides, energy efficiency is increased around 7% and 11% at −10 °C and 35 °C ambient temperatures, respectively, which are extreme scenarios for electric vehicles. Moreover, the developed algorithm provides a successful thermal management strategy regarding waste heat recovery from hydrogen vessels, the temperature of which is controlled by the fuel supply system.