Fuel cell system

Abstract

A fuel cell system (10) includes: a fuel cell stack (20) which receives a reaction gas and generates electricity; and a controller (70) which supplies to the fuel cell stack (20), a high-pressure reaction gas as compared to the normal operation pressure when the temperature of the fuel cell stack (20) is below a predetermined threshold value and a water amount contained in the fuel cell stack (20) is below a predetermined threshold value. When the reaction gas supply pressure is increased, the water removal amount by the reaction gas is lowered and the water balance in the fuel cell stack proceeds in such a direction that the water contained in the reaction gas is accumulated in a film-electrode assembly. However, since the water amount contained in the fuel cell stack (20) is below the threshold value, it is possible to increase the low-temperature start performance while suppressing flooding.

Description

technical field [0001] The present invention relates to a fuel cell system including a fuel cell stack that generates electricity by receiving a supply of reaction gas. Background technique [0002] A fuel cell stack has a stack structure in which a plurality of unit cells are stacked in series. Each unit cell has a membrane-electrode assembly in which an anode is disposed on one side of an electrolyte membrane and a cathode is disposed on the other side. By supplying a reaction gas to the membrane-electrode assembly, an electrochemical reaction is performed, and chemical energy is converted into electrical energy. Among them, a solid polymer electrolyte fuel cell stack using a solid polymer membrane as an electrolyte is expected to be used as a vehicle-mounted power source because it is easy to be compacted at low cost and has a high output density. [0003] However, in the cell reaction of the fuel cell system, since moisture is generated, there is a concern that the mois...

AI Technical Summary

Problems solved by technology

At the time of low-temperature start-up, in the state where sufficient moisture required to ensure proton conductivity required for power generation is contained in the membrane-electrode assembly, if the reaction gas supply pressure is increased, flooding may occur, which may be caused by reaction gas diffusion. The increase in concentration polarization due to performance degradation leads to a decrease in the output characteristics of the fuel cell stack

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