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EP-4086994-B1 - MEMBRANE-ELECTRODE ASSEMBLY, METHOD FOR MANUFACTURING SAME, AND FUEL CELL COMPRISING SAME

EP4086994B1EP 4086994 B1EP4086994 B1EP 4086994B1EP-4086994-B1

Inventors

  • KONG, NAK WON
  • NAM, Kyoung Sik
  • SONG, Ka Young
  • KIM, JUN YOUNG
  • LEE, JU SUNG

Dates

Publication Date
20260506
Application Date
20201223

Claims (13)

  1. A fuel cell comprising: a membrane-electrode assembly (1000) comprising a first electrode (1210); a second electrode (1220); and a polymer electrolyte membrane (1100) between the first and second electrodes (1210, 1220), wherein the first electrode (1210) has a first surface that faces the polymer electrolyte membrane (1100) and a second surface opposite the first surface, the first surface having a first patterned structure (1211), and the second surface having a second patterned structure (1212); and a separator (1510) disposed on the second patterned structure (1212) of the first electrode (1210), wherein the separator (1510) has a third surface that faces the membrane-electrode assembly (1000) and a fourth surface opposite the third surface, the third surface comprising a groove-shaped channel part (1511) functioning as a fluid path and a non-channel part (1512), the fuel cell characterized in that : the second patterned structure (1212) comprises at least one projected pattern (1212a) extending in a direction parallel to the first and second surfaces and a recessed pattern (1212b) adjoining the projected pattern (1212a); and the membrane-electrode assembly (1000) and the separator (1510) are aligned such that the non-channel part (1512) corresponds to the recessed pattern (1212b).
  2. The fuel cell according to claim 1, wherein the first electrode (1210) comprises an intermediate layer (1213) between the first and second patterned structures (1211, 1212), and a thickness of the intermediate layer (1213) is 10 to 90% of a thickness of the first electrode (1210).
  3. The fuel cell according to claim 1, wherein the first patterned structure (1211) is different from the second patterned structure (1212).
  4. The fuel cell according to claim 1, wherein the first patterned structure (1211) has a plurality of projected parts scattered over an entire region of the first surface.
  5. The fuel cell according to claim 4, wherein each of the projected parts has a height of 1 to 50 µm, and a circle circumscribed about a base plane of each of the projected parts has a diameter of 10 to 1000 µm.
  6. The fuel cell according to claim 1, wherein the projected pattern (1212a) has a height of 1 to 50 µm and a width of 10 to 1000 µm.
  7. The fuel cell according to claim 1, wherein the projected pattern (1212a) has a zigzag shape.
  8. A method for manufacturing the fuel cell according to claim 1, the method comprising: (i) manufacturing the membrane-electrode assembly (1000); and (ii) disposing the separator (1510) on the second patterned structure (1212) of the first electrode (1210), wherein the manufacturing the membrane-electrode assembly (1000) comprises: applying a catalyst dispersion (1210') to a first release film (10) having a first recessed pattern (11) corresponding to the second patterned structure (1212); covering the applied catalyst dispersion (1210') with a second release film (30) having a second recessed pattern or a plurality of holes (31) corresponding to the first patterned structure (1211); drying at least a surface of the catalyst dispersion (1210') to form the first electrode (1210); removing the second release film (30); transferring the first electrode (1210) to the polymer electrolyte membrane (1100); and removing the first release film (10), the method characterized in that when the separator (1510) is disposed on the second patterned structure (1212) of the first electrode (1210), the membrane-electrode assembly (1000) and the separator (1510) are aligned such that the non-channel part (1512) corresponds to the recessed pattern (1212b).
  9. The method according to claim 8, wherein the first recessed pattern (11) comprises at least one groove extending in a direction parallel to a surface of the first release film (10), and the groove has a depth of 1 to 50 µm.
  10. The method according to claim 8, wherein the second recessed pattern is different from the first recessed pattern (11).
  11. The method according to claim 8, wherein the second release film (30) has the plurality of holes (31), the second release film (30) has a thickness of 10 to 100 µm, and each of the holes (31) has a diameter of 10 to 1000 µm.
  12. The method according to claim 8, further comprising drying the first electrode (1210) immediately after removing the second release film (30).
  13. The fuel cell according to claim 1, wherein the projected pattern (1212a) of the second patterned structure (1212) has an identical shape to the channel part (1511) and a width not greater than a width of the channel part (1511).

Description

[TECHNICAL FIELD] The present disclosure relates to a membrane-electrode assembly, a method of manufacturing the same, and a fuel cell including the same, and more particularly to a membrane-electrode assembly having an increased active area, improved fluid management ability, and reduced gas transport resistance due to a double-sided patterned electrode, a method of manufacturing the same, and a fuel cell including the same. [Background Art] A polymer electrolyte membrane fuel cell (PEMFC), which is configured to generate electricity using a structure in which unit cells, each of which includes a membrane-electrode assembly (MEA) and a separator (also referred to as a bipolar plate), are stacked, has attracted attention as a next-generation energy source capable of replacing fossil fuels due to high energy efficiency and environmentally friendly characteristics thereof. The membrane-electrode assembly generally includes an anode (also referred to as a fuel electrode), a cathode (also referred to as an air electrode), and a polymer electrolyte membrane (PEM) therebetween. When fuel such as hydrogen gas is supplied to the anode, hydrogen ions (H+) and electrons (e-) are generated at the anode as the result of hydrogen oxidation reaction. The generated hydrogen ions are transported to the cathode via the polymer electrolyte membrane (PEM), and the generated electrons are transported to the cathode via an external circuit. Oxygen in air supplied to the cathode is bonded with the hydrogen ions and the electrons, and water is generated as the result of reduction. Since each of an electrode and a polymer electrolyte membrane (PEM) of a general membrane-electrode assembly has a smooth surface, the active area of each of the electrode and the polymer electrolyte membrane is substantially equal to the projected area of the electrode. In order to increase the active area of each of the electrode and the polymer electrolyte membrane, therefore, the size of the electrode must be increased, which causes a cost increase. In addition, when a separator including a flow channel part that functions as a fluid path (i.e. a groove) and the other part, i.e. a non-channel part, is pressure-fastened to the membrane-electrode assembly, the portion of the electrode corresponding to the non-channel part is compressed, whereby movement of a fluid (e.g. oxygen, hydrogen, or water) is disturbed. In particular, oxygen that must be reduced at the cathode is merely about 20% of air supplied to the cathode, and water generated as the result of oxygen reduction reaction disturbs the spread of oxygen in the cathode. For the cathode, therefore, it is particularly required to increase an active area, to achieve smooth discharge of water, and to reduce oxygen transport resistance. In order to increase the active area of each of the electrode and the polymer electrolyte membrane, forming unevenness on the surface of the polymer electrolyte membrane has been proposed. However, this method has a problem in that it is impossible to use a decal transfer method, which is a general electrode forming method, and it is required to directly coat the polymer electrolyte membrane with a catalyst dispersion. Furthermore, if a catalyst dispersion state of the catalyst dispersion directly coated on the polymer electrolyte membrane is poor, the catalyst cannot permeate into patterned grooves of the polymer electrolyte membrane, whereby interfacial resistance between the electrode and the polymer electrolyte membrane is increased. Meanwhile, in order to minimize oxygen transport resistance of the cathode, forming a cathode constituted by a plurality of sub-electrodes spaced apart from each other has been proposed. However, exposure of the electrolyte membrane between the sub-electrodes causes loss in active area and deterioration in durability of the membrane-electrode assembly. JP 2006 310166 A relates to a cell structure of a fuel cell having a configuration in which a catalyst layer and a porous layer serving as an electrode are laminated on both surfaces of an electrolyte membrane. KR 2012 0032331 A relates to a manufacturing method of flat tubular electrode supporter comprising: a step of extrusion-molding an flat-pipe type electrode support in which a fuel flow part penetrating along longitudinal direction is formed; a step of cutting the electrode support to the size of a unit cell by pressuring both ends of the electrode support; a step of forming uneven patterns on the surface of the electrode support; and a step of drying the support. The step of forming uneven patterns is conducted by pressurizing a molding flame in which a stamp pattern corresponding to the uneven patterns in the side contacting the electrode support. JP 2009 170271 A relates to a method for manufacturing a membrane electrode assembly constituting a fuel cell. KR 2019 0079137 A relates to an apparatus for manufacturing an electrode for a membrane electrode assembly and a method for