Membrane electrode assembly for fuel cells and method of manufacturing the membrane electrode assembly for fuel cells
A membrane electrode assembly includes an electrolyte membrane stacked between different electrodes, wherein an ionomer layer of the electrolyte membrane comprises an adjacent electrode, a first layer having at least a same cross-sectional area as that of the adjacent electrode, a reinforcing layer and a second layer stacked at a side of the first layer, the second layer having at least the same cross-sectional area as that of the reinforcing layer.
1. A method of manufacturing a membrane electrode assembly (MEA) for fuel cells comprising:
(a) coating release paper with an electrode slurry to produce a cathode and an anode:
(b) coating the cathode and the anode with a cathode-side first ionomer layer and an anode-side first ionomer layer, respectively;
(c) coating each of two opposing sides of a reinforcing layer with a second ionomer layer;
(d) conducting transfer by placing the reinforcing layer coated with the second ionomer layers between the cathode coated with the cathode-side first ionomer layer and the anode coated with the anode-side first ionomer layer;
(e) stacking a sub-gasket by adhesion on each edge of opposing surfaces of a stacked group of the cathode coated with the cathode-side first ionomer layer, the anode coated with the anode-side first ionomer layer, and the reinforcing layer coated with the second ionomer layers to produce a membrane electrode assembly; and
(f) heat-treating the membrane electrode assembly by application of heat and pressure thereto,
wherein each of the cathode-side first ionomer layer and the anode-side first ionomer layer has a smaller cross-sectional area than a cross-sectional area of the reinforcing layer,
wherein a thickness of each of the second ionomer layers is less than a thickness of each of the cathode-side first ionomer layer and the anode-side first ionomer layer,
wherein each of the cathode-side first ionomer layer and the anode-side first ionomer layer has a larger cross-sectional area than each cross-sectional area of the cathode and the anode, and
wherein the cathode-side first ionomer layer is in direct contact with one of the second ionomer layers and the anode-side first ionomer layer is in direct contact with the other of the second ionomer layers.
2. The method according to claim 1 , wherein the reinforcing layer coated with the second ionomer layers includes a porous film having a thickness of 3 to 50 μm and made of expanded polytetrafluoroethylene(e-PTFE).
3. The method according to claim 1 , wherein the formation of the cathode-side, anode-side, and second ionomer layers in steps (b) and (c) is carried out using spraying.
4. The method according to claim 1 , wherein the transfer of step (d) is carried out using roll pressing at a temperature of 90 to 120° C., a pressure of 40 to 130 kgf, and a rate of 0.1 to 1.0 m/min, or using plate pressing at a temperature of 100 to 180° C. and a pressure of 0.1 to 10.0 MPa, for 10 to 500 seconds.
5. The method according to claim 1 , wherein the bonding of the membrane electrode assembly (MEA) in steps (e) and (f) is carried out using roll pressing or plate pressing.
6. A method of manufacturing a membrane electrode assembly (MEA) for fuel cells comprising:
(a) coating release paper with an electrode slurry to produce a cathode and an anode:
(b) coating the cathode and the anode with a cathode-side first ionomer layer and an anode-side first ionomer layer, respectively;
(c) coating each of two opposing sides of a reinforcing layer with a second ionomer layer;
(d) conducting transfer by placing the reinforcing layer coated with the second ionomer layers between the cathode coated with the cathode-side first ionomer layer and the anode coated with the anode-side first ionomer layer;
(e) stacking a sub-gasket by adhesion on each edge of opposing surfaces of a stacked group of the cathode coated with the cathode-side first ionomer layer, the anode coated with the anode-side first ionomer layer, and the reinforcing layer coated with the second ionomer layers to produce a membrane electrode assembly; and
(f) heat-treating the membrane electrode assembly by application of heat and pressure thereto,
wherein each of the cathode-side first ionomer layer and the anode-side first ionomer layer has a smaller cross-sectional area than a cross-sectional area of the reinforcing layer,
wherein a thickness of each of the second ionomer layers is less than a thickness of each of the cathode-side first ionomer layer and the anode-side first ionomer layer,
wherein each of the cathode-side first ionomer layer and the anode-side first ionomer layer has a larger cross-sectional area than each cross-sectional area of the cathode and the anode, and
wherein the cathode-side first ionomer layer is disposed between the reinforcing layer and the cathode, and the anode-side first ionomer layer is disposed between the reinforcing layer and the anode.