The capacity of power batteries is an important factor affecting the structural composition of fuel cell vehicles. By comparing the durability and lowtemperature environmental adaptability of power batteries and fuel cells, it is concluded that equipping largecapacity power batteries can reduce the operating time of fuel cells under adverse working conditions and improve lowtemperature cold start performance. Research on the braking energy recovery of fuel cell vehicles has found that increasing the power battery capacity can improve the regenerative braking recovery ability of the vehicle during longdistance slow braking. The analysis of the full lifecycle cost of fuel cell systems indicates that a reasonable match between power batteries and fuel cells can reduce system costs. Furthermore, it is pointed out that one of the important future development directions for fuel cell vehicles is plugin electrification, which provides some guidance for the commercial development of fuel cell vehicles.