Flow control for multiple stacks

A method of making a fuel cell stack comprising the steps of:

• (a) positioning a plurality of fuel cells adjacent one another, at least one fuel cell of said plurality of fuel cells having an electrode plate with a flow field formed therein, a membrane electrode assembly (MEA) and a compressible fluid-permeable diffusion media disposed between said MEA and said electrode plate;
• (b) compressing said adjacent fuel cells together so that in said at least one fuel cell a portion of said diffusion media intrudes into said flow field of said adjacent electrode plate;
• and
• (c) adjusting said compression so that a velocity of a feed stream flowing through the fuel cell stack is maintained above a predetermined level while maintaining at least some intrusion of said portion of said diffusion media into said flow field.

A method of making a fuel cell stack comprising the steps of:

• (a) positioning a plurality of fuel cells adjacent one another, at least one fuel cell of said plurality of fuel cells having an electrode plate with a flow field formed therein, a membrane electrode assembly (MEA) and a compressible fluid-permeable diffusion media disposed between said MEA and said electrode plate;
• (b) compressing said adjacent fuel cells together so that in said at least one fuel cell a portion of said diffusion media intrudes into said flow field of said adjacent electrode plate;
• and
• (c) adjusting said compression so that a feed stream flowing through the fuel cell stack experiences a pressure drop of a magnitude generally equal to a known pressure drop of a different fuel cell stack.

A method of making a fuel cell stack comprising the steps of:

• (a) positioning a plurality of fuel cells adjacent one another, at least one fuel cell of said plurality of fuel cells having an electrode plate with a flow field formed therein, a membrane electrode assembly (MEA) and a compressible fluid-permeable diffusion media disposed between said MEA and said electrode plate;
• (b) compressing said adjacent fuel cells together so that in said at least one fuel cell a portion of said diffusion media intrudes into said flow field of said adjacent electrode plate;
• and
• (c) adjusting said compression so that, at a predetermined power output of the fuel cell stack, a feed stream flowing through said fuel cell stack is adjusted toward a value corresponding to a known pressure drop of a different fuel cell stack at a substantially similar power output.

A method of making a fuel cell stack comprising the steps of:

• (a) positioning a plurality of fuel cells adjacent one another, at least one fuel cell of said plurality of fuel cells having an electrode plate with a flow field formed therein, a membrane electrode assembly (MEA) and a compressible fluid-permeable diffusion media disposed between said MEA and said electrode plate;
• (b) compressing said adjacent fuel cells together so that in said at least one fuel cell a portion of said diffusion media intrudes into said flow field of said adjacent electrode plate;
• (c) supplying a fluid flow through said fuel cell stack including said flow field;
• and
• (d) changing an intrusion of said diffusion media into said flow field of said adjacent electrode plate and achieving a predetermined flow characteristic while maintaining at least some intrusion of said portion of said diffusion media into said flow field.

A method of making a fuel cell stack comprising the steps of:

• (a) positioning a plurality of fuel cells adjacent one another, at least one fuel cell of said plurality of fuel cells having an electrode plate with a flow field formed therein, a membrane electrode assembly (MEA) and a compressible fluid-permeable diffusion media disposed between said MEA and said electrode plate;
• (b) compressing said adjacent fuel cells together so that in said at least one fuel cell a portion of said diffusion media intrudes into said flow field of said adjacent electrode plate;
• and
• (c) changing an intrusion of said diffusion media into said flow field of said adjacent electrode plate and achieving a predetermined flow characteristic.

A method of making a fuel cell stack comprising the steps of:

• positioning a plurality of fuel cells adjacent one another, at least one fuel cell of said plurality of fuel cells having an electrode plate with a flow field formed therein, a membrane electrode assembly (MEA) and a compressible fluid-permeable diffusion media disposed between said MEA and said electrode plate;
• compressing said adjacent fuel cells together so that in said at least one fuel cell a portion of said diffusion media intrudes into said flow field of said adjacent electrode plate;
• supplying a fluid stream to said plurality of fuel cells;
• monitoring a pressure drop of said fluid stream across said plurality of fuel cells;
• and
• adjusting a compression of said plurality of fuel cells so that said pressure drop is within a predetermined range.