Experimental Study On The Performance Of Metal Foam Flow Field PEMFC

Proton exchange membrane fuel cell(PEMFC)is a new type of energy device that converts chemical energy in fuel directly into electric energy by electrochemical reaction.In internal combustion engines,the chemical energy of the fuel must first be converted into heat energy.The energy conversion efficiency of PEMFC is higher.compared with the internal combustion engine.The conventional graphite flow field in PEMFC is prone to the uneven distribution of reaction gas due to the existence of ribs.In order to improve this phenomenon,metal foam is used as a new type of PEMFC flow field.The metal foam flow field arrangement,structural parameters of metal foam,and the effect of metal foam filling in conventional parallel flow field on the performance of PEMFC are studied in this paper.In order to study the effect of metal foam flow field arrangement on PEMFC performance,we would like to study three cases,namely the use of metal foam either in the cathode side or anode side,and the simultaneous use of metal foam in both sides and compared with the conventional parallel flow PEMFC.The effect of different operating conditions on the performance of PEMFC was studied.Experimental results showed that nickel metal foam flow field can make the temperature distribution at the MEA more uniform,which is conducive to the durability of the MEA,and improves the fuel utilization rate.The nickel metal foam flow field has water retention function in low humidity condition.However,when relative humidity(RH)is high,the cathode side using nickel metal foam flow field is more prone to flooding.In view of the flooding phenomenon of the metal foam flow field applied to the PEMFC cathode side,and the difference of electrochemical reaction and the nature of the reaction gas between PEMFC anode and cathode.The structural parameters of the metal foam flow field are further studied in this paper.The effects of the depth of the metal foam flow field,the compression ratio of the metal foam flow field and the PPI of the metal foam flow field on the PEMFC performance are studied respectively.The experiment result show that reducing the depth of metal foam flow field is conducive to improving the performance of PEMFC.The metal foam flow field with a compression ratio of 0.375 and a pore density of 110PPI can promote the uniform distribution of hydrogen and improve the PEMFC performance,When the metal foam flow field is separately applied to the anode side of PEMFC.The metal foam flow field with a compression ratio of 0.75 and a pore density of 75PPI should be selected,When the metal foam flow field is separately applied to the cathode side of PEMFC.With the increase of compression ratio,the pressure drop between the inlet and outlet is increased,and the water management at the cathode side is improved.The metal foam of 75PPI can promote the liquid water of the gas diffusion layer on the cathode side to enter the metal foam flow field and discharge in time,which improves the water management of the cathode side,compared with the metal foam of 110PPI and35PPI.A new filled flow field is formed by filling metal foam in the flow field of conventional parallel flow field,and is compared with the parallel flow field and the wavy-like flow field PEMFC.The experiment result show that compared with the conventional parallel flow field PEMFC,the hydrogen consumption of wavy-like flow field and filled flow field is reduced by 5.65%and 9.35%,and the air consumption is reduced by 9.74%and 15.03%,when the power density is 0.6w/cm~2and under the same operating conditions.