Polymer electrolyte fuel cell, method of manufacturing the same and inspection method therefor

A method of manufacturing a polymer electrolyte fuel cell, comprising processes of:

• forming a plurality of unit cells;
• stacking the plurality of unit cells to form a cell stack;
• and tightening the cell stack in a stacking direction of the stack;
• the process of forming the plurality of unit cells comprising steps of:
• placing, on opposite major surfaces of a hydrogen ion conductive polymer electrolyte membrane, a first and a second electrode, each electrode comprising a gas diffusion layer and a catalyst layer, to form an electrolyte membrane-electrode assembly;
• placing a first electrically conductive separator plate contacting the first electrode and having a first gas flow channel for supplying and exhausting a fuel gas to and from the first electrode;
• and placing a second electrically conductive separator plate contacting the second electrode and having a second gas flow channel for supplying and exhausting an oxidant gas to and from the second electrode;
• and further comprising an inspection process comprising steps of:
• measuring a short-circuit conductivity of each electrolyte membrane-electrode assembly and/or measuring a hydrogen leak current of each unit cell;
• and removing such electrolyte membrane-electrode assemblies or unit cells or cell stack or cell stacks that have a short-circuit conductivity exceeding a predetermined short-circuit conductivity value or have a hydrogen leak current exceeding a predetermined hydrogen leak current value.

A method of manufacturing a polymer electrolyte fuel cell, comprising processes of:

• forming a plurality of unit cells;
• stacking the plurality of unit cells to form a cell stack;
• and tightening the cell stack in a stacking direction of the stack;
• the process of forming the plurality of unit cells comprising steps of:
• placing, on opposite major surfaces of a hydrogen ion conductive polymer electrolyte membrane, a first and a second electrode, each electrode comprising a gas diffusion layer and a catalyst layer, to form an electrolyte membrane-electrode assembly;
• placing a first electrically conductive separator plate contacting the first electrode and having a first gas flow channel for supplying and exhausting a fuel gas to and from the first electrode;
• and placing a second electrically conductive separator plate contacting the second electrode and having a second gas flow channel for supplying and exhausting an oxidant gas to and from the second electrode;
• wherein the process of forming the plurality of unit cells further comprises, before the step of forming each electrolyte membrane-electrode assembly, a step of smoothing both major surfaces of each gas diffusion layer.

An inspection method for a polymer electrolyte fuel cell comprising a cell stack having a plurality of unit cells tightened in a stacking direction of the stack, each unit cell comprising:

• an electrolyte membrane-electrode assembly comprising a hydrogen ion conductive polymer electrolyte membrane and first and second electrodes respectively placed on opposite major surfaces of the electrolyte membrane, each electrode comprising a gas diffusion layer and a catalyst layer;
• a first electrically conductive separator plate contacting the first electrode and having a first gas flow channel for supplying and exhausting a fuel gas to and from the first electrode;
• and a second electrically conductive separator plate contacting the second electrode and having a second gas flow channel for supplying and exhausting an oxidant gas to and from the second electrode;
• the inspection method comprising, before operation of electric power generation of the polymer electrolyte fuel cell, and before or after formation of the cell stack, steps of:
• measuring a short-circuit conductivity of each electrolyte membrane-electrode assembly and/or measuring a hydrogen leak current of each unit cell;
• and inspecting whether the measured short-circuit conductivity exceeds a predetermined short-circuit conductivity value, and/or whether the measured hydrogen leak current exceeds a predetermined hydrogen leak current value.