Simulation Of Bipolar Plates Thermal Conductivity Of Proton Exchange Membrane Fuel Cells

Proton exchange membrane fuel cell(PEMFC)is an energy conversion device using hydrogen as fuel and avoided the burning process.PEMFC is catching rising attention with advantages like high energy conversion efficiency,clean,fast-start and no noise.The heat dissipation of PEM is important to keep the temperature distributed uniformly and between the working window.For high power PEMFC,manufacturing cooling flow is the universal way to transfer heat which corresponded with high cost and more complicated structure The paper established single channel and muti-channel PEMFC models via Fluent,then researched the enhanced thermal conductivity of bipolar plates can optimize the heat management of PEMFC.Firstly,the paper established single channel PEMFC model and analyzed how the working voltage,thermal conductivity and heat-exchange way influenced the temperature distribution inside the PEMFC.The results showed that: the highest temperature is in the membrane,the lower working voltage leads to more heat production and lower energy efficiency;under the convection current,the highest temperature lowered 0.40 K and the temperature difference lowered to 0.30 K when the thermal conductivity enhanced to 500 W/m·K.Secondly,the paper established 10\20\30 channels PEMFC models with cooling flow,compared the consequences of the enhanced thermal conductivity and the adding of cooling flow.The results showed that: the more channels corresponding to big size bipolar plates and higher central temperature,the 30 channels PEMFC model's central temperature lowered the most when enhance the heat conductivity;the highest temperature in membrane is linear dependence with the flow rate when adding the cooling flow,also it is irrelevant with the PEMFC size;the membrane temperature difference is 3.0 K when the cooling flow rate is 0.035 m/s,the 20 channels model can reach the same result with thermal conductivity rise to 200 W/m·K,the 30 channels model can reach the same result with thermal conductivity rise to 500 W/m·K.The conclusion is that enhancing the thermal conductivity of bipolar plates can reach the same cooling effect as the cooling flow exists.Finally,the paper established large size PEMFC with the t 500 W/m·K thermal conductivity.When the transverse size reached 80 flows(0.128m),the PEM temperaturedifference reached 10 K,which was smaller than the PEMFC with 40 flows(0.064m)under 100 W/m·K,It means that the high thermal conductivity PEMFC size can be two times under the condition.