Abstract: A disassembly procedure of a fuel cell places a sloped edge of a cracking tool on a bottom of a recess. The bottom of the recess as a point of application, an opening edge of the recess where a flat side of the cracking tool is placed, is a point of support, and force is applied at a base end of the cracking tool. Leverage is applied to the point of application by an external force creating a crack starts in a separator. The crack goes from the point of application toward a position outside electrodes of an MEA (membrane electrode assembly) but inside sealing members. The procedure then removes the broken separator to expose the MEA outside and cuts off an electrolyte membrane along a cut line CL outside the electrodes but inside the sealing members.

Abstract: A membrane electrode assembly for a fuel cell includes an electrolyte membrane having ionic conductivity and a pair of gas diffusion electrodes having gas diffusivity and electric conductivity. Each of the pair of gas diffusion electrodes is bonded to one side or the other of the electrolyte membrane in a thickness direction. A bonding force for bonding at least one part of an outer circumferential area of the gas diffusion electrodes to the electrolyte membrane is set to at an inferior level to that of the bonding force for bonding a central area of the gas diffusion electrodes to the electrolyte membrane, so that an area of the electrolyte membrane facing the at least one part of the outer circumferential area of the gas diffusion electrodes can be protected from damage.

Abstract: A disassembly procedure of a fuel cell 10 first provides a cracking tool 12 having a sloped edge and places the sloped edge of the cracking tool 12 on a bottom of a recess 11. The disassembly procedure subsequently sets the bottom of the recess 11 where the sloped edge of the cracking tool 12 is placed, as a point of application, an opening edge of the recess 11 where a flat side of the cracking tool 12 is placed, as a point of support, and a base end of the cracking tool 12 where a force is applied, as a point of power, and applies an external force to the point of application by the principle of leverage. A crack starts from the point of application in a separator 6. The crack goes from the point of application toward a position outside electrodes 4 and 5 of an MEA (membrane electrode assembly) 2 but inside sealing members 8.

Abstract: A membrane electrode assembly for a fuel cell includes an electrolyte membrane having ionic conductivity and a pair of gas diffusion electrodes having gas diffusivity and electric conductivity. Each of the pair of gas diffusion electrodes is bonded to one side or the other of the electrolyte membrane in a thickness direction. A bonding force for bonding at least one part of an outer circumferential area of the gas diffusion electrodes to the electrolyte membrane is set to at an inferior level to that of the bonding force for bonding a central area of the gas diffusion electrodes to the electrolyte membrane, so that an area of the electrolyte membrane facing the at least one part of the outer circumferential area of the gas diffusion electrodes can be protected from damage.

Abstract: A fuel cell wherein (a) an MEA and a separator are layered in a direction perpendicular to gravity, and (b) a fuel gas inlet, a fuel gas outlet and a fuel gas passage, and an oxidant gas inlet, an oxidant gas outlet and an oxidant gas passage are arranged such that a humidity distribution of fuel gas at an anode and a humidity distribution of oxidant gas at a cathode are counter to each other. The fuel cell has a coolant passage, and the humidity distribution and a temperature distribution at the cathode correspond to each other. Each gas passage has a concave portion at a lower wall thereof.

Abstract: A fuel cell system calculates a water quantity Qw produced by a fuel cell from an output current I of the fuel cell, and at the same time calculates saturated water vapor contents Qwa and Qwc in exhaust gases based on exhaust-gas flow rates Qa and Qc, exhaust-gas pressures Pa and Pc, and exhaust-gas temperatures Ta and Tc of the anode side and the cathode side, respectively. Then the system calculates a water quantity control ratio that is defined as t=Qw/(Qwa+Qwc) and controls operation of the fuel cell by controlling one or more of the exhaust-gas flow rates Qa and Qc, the exhaust-gas pressures Pa and Pc, the exhaust-gas temperatures Ta and Tc, and a current I of the anode side and the cathode side in a direction such that a deviation At between the water quantity control ratio t and a value of one is canceled out. By this control, the fuel cell can be operated with excellent performance, without humidifying gases of the anode side and the cathode side.