Stop method of vehicle electrical power system

A stop method of a vehicle electrical power system that includes:

• a fuel cell that generates electric power when fuel gas is supplied to an anode flow channel and oxidant gas is supplied to a cathode flow channel;
• an electrical storage device that stores electric power generated by the fuel cell;
• a stop switch that generates a signal to cause electric power generation by way of the fuel cell to stop;
• and
• a load that is driven by way of supply of electric power from the fuel cell or the electrical storage device,
• wherein, after the stop switch has been operated, the system executes charge processing to charge electric power generated by the fuel cell to the electrical storage device, and concentration adjustment processing to adjust a concentration of gas inside at least one of the anode flow channel and the cathode flow channel, the method comprising the steps of:
• calculating a charge time corresponding to a time in which charge processing can be executed, after the stop switch has been operated, by subtracting a time required in the concentration adjustment processing from a predetermined stop processing permitted time;
• calculating a target charge amount of the electrical storage device;
• executing the charging processing while controlling output of the fuel cell based on the charge time and the target charge amount;
• and
• executing the concentration adjustment processing after the charge processing has ended.