Elucidating the automobile proton exchange membrane fuel cell of innovative double-cell structure by full-morphology simulation

•The full-morphology simulation of the large-scale automobile PEM fuel cell is proposed.•All components, the realistic morphology of distribution area and the coolant flow is fully considered.•The advantages and disadvantages and its influence on physical and chemical processes of double-cell structure are deeply analyzed.•Novel double-cell structure can significantly improve power density (almost 20%) under actual operating conditions. The structural design of PEM fuel cell is crucial to improving its power density, and the cell structure largely depends on the bipolar plate (BP). This study compares the conventional single-cell structure and double-cell structure through three-dimensional (3D) large-scale (cell area: 312 cm2) full-morphology simulation. As for the double-cell structure, the channels are arranged in a dislocation manner and there is one cooling flow field per two cells. For the structure of the BP, we also fully considered the realistic morphology of distribution area and the coolant flow. It is found that the heat dissipation effect of double-cell structure is worse but the performance is very close compared to single-cell structure. Moreover, its volumetric power density is significantly improved (∼ 20%) due to the reduction in height. It is also found that increasing the velocity of coolant in the double-cell structure increases the performance first and then decreases.