Membrane electrode assembly for fuel cell and fuel cell stack

A fuel cell stack, comprising:

• unit cells in which membrane electrode assemblies (MEAs) are disposed at a center and separators are positioned closely adjacent to two opposite sides of the MEAs;
• and
• a pressing plate that presses and supports the unit cells,
• each MEA comprising:
• an electrolyte membrane for a fuel cell;
• a microporous layer (MPL) that is disposed at a surface of the electrolyte membrane;
• a backing layer that is disposed on the MPL;
• and
• a circumferential edge protective layer disposed at a circumferential edge of the electrolyte membrane, the circumferential edge protective layer being located between the backing layer and the electrolyte membrane,
• an entire extension of the backing layer along a direction perpendicular to a stacking direction of the MEA being positioned farther inside of the MEA than an entire extension of the electrolyte membrane along the direction perpendicular to the stacking direction of the MEA being positioned farther inside of the MEA, an entire extension of the MPL along the direction perpendicular to the stacking direction of the MEA being positioned farther inside of the MEA than the entire extension of the backing layer along the direction perpendicular to the stacking direction of the MEA.

A membrane electrode assembly (MEA), comprising:

• an electrolyte membrane for a fuel cell;
• a microporous layer (MPL) that is disposed at a surface of the electrolyte membrane;
• a backing layer that is disposed on the MPL;
• and
• a circumferential edge protective layer that is disposed at a circumferential edge of the electrolyte membrane,
• an outermost periphery of the microporous layer (MPL) and an innermost periphery of the circumferential edge protective layer being disposed opposite to each other and facing each other, and
• an entire extension of the backing layer along a direction perpendicular to a stacking direction of the MEA being positioned farther inside of the MEA than an entire extension of the electrolyte membrane along the direction perpendicular to the stacking direction of the MEA being positioned farther inside of the MEA, an entire extension of the MPL along the direction perpendicular to the stacking direction of the MEA being positioned farther inside of the MEA than the entire extension of the backing layer along the direction perpendicular to the stacking direction of the MEA.