JP5114899B2 - Polymer electrolyte fuel cell - Google Patents

Description

  The present invention relates to a polymer electrolyte fuel cell.

  A solid polymer fuel cell is one in which a fuel gas containing hydrogen and an oxidant gas containing oxygen such as air are electrochemically reacted by a gas diffusion electrode, and electricity and heat are generated simultaneously. FIG. 7 shows an exploded cross-sectional view showing the basic unit cell structure of such a polymer electrolyte fuel cell. The side in which fuel gas such as hydrogen is involved is called an anode, and in the figure, a is added after the symbol, the side in which oxidant gas such as air is involved is called the cathode, and in the drawing, c is added after the symbol. did.

  In FIG. 7, a catalytic reaction layer mainly composed of carbon powder carrying a platinum-based metal catalyst is disposed on both surfaces of a polymer electrolyte membrane 101 that selectively transports hydrogen ions. Further, a pair of diffusion layers having both gas permeability and conductivity are disposed in close contact with the outer surface of the catalyst reaction layer. The diffusion layer and the catalytic reaction layer constitute the electrodes 104a and 104c. The membrane electrode assembly 105 is formed by the electrodes 104 a and 104 c and the polymer electrolyte membrane 101. The membrane electrode assembly is generally referred to as MEA.

  The membrane electrode assembly 105 is mechanically fixed to the outside of the membrane electrode assembly 105, adjacent membrane electrode assemblies are electrically connected to each other in series, and a reaction gas is supplied to the electrode, and the reaction is performed. Conductive separators 107 a and 107 c formed on the surface in contact with the membrane electrode assembly 105 are provided with gas flow paths 106 a and 106 c for carrying away the gas generated by the above and surplus gas. Between the membrane electrode assembly 105 and the conductive separators 107a and 107c, the membrane electrode assembly gasket 110a prevents the supplied fuel gas or oxidant gas from leaking to the outside or mixing the two gases with each other. 110c.

  When a unit cell is formed by combining the membrane electrode assembly 105 and the pair of separators 107a and 107c, if the electrodes 104a and 104c of the membrane electrode assembly 105 and the gas flow paths 106a and 106c of the separators 107a and 107c are displaced, The reaction area effective for the electrochemical reaction is reduced. In some cases, the positions of the membrane electrode assembly gaskets 110a and 110c may be shifted and gas may be leaked.

Therefore, in the conventional polymer electrolyte fuel cell, the positioning pin 111 is passed through a through hole provided in a place other than the reaction surface of the membrane electrode assembly 105 and the separators 107a and 107c, and positioning is performed by the retaining ring part 112 from the opposite side. By preventing the pins 111 from coming off, the membrane electrode assembly 105 and the pair of separators 107 are integrated (see, for example, Patent Document 1).
JP 2000-12067 A

  However, the conventional polymer electrolyte fuel cell has the following problems. That is, there is a problem that the use of fastening parts such as positioning pins may increase the number of parts, the manufacturing cost, and prolong the manufacturing lead time.

  The polymer electrolyte fuel cell of the present invention solves the above-mentioned conventional problems, and without increasing the number of parts, manufacturing cost, and prolonging the manufacturing lead time, the membrane electrode assembly and the pair of separators It is an object of the present invention to provide a polymer electrolyte fuel cell that can be positioned and integrated relatively accurately and can realize stable sealing performance and output.

In order to solve the above-mentioned problems, the present invention provides a membrane electrode assembly comprising a solid polymer electrolyte membrane and a pair of electrodes having a catalytic reaction layer disposed with the solid polymer electrolyte membrane interposed therebetween, and the membrane electrode A frame body that holds the outer periphery of the assembly and is integrated with the membrane electrode assembly, and a fuel gas containing hydrogen is supplied to one of the electrodes of the membrane electrode assembly and an oxidant gas containing oxygen is supplied to the other A pair of conductive separators having means for supplying, a plurality of protrusions in a part of the frame, and at least one unit cell having a hole to fit the protrusion in the separator. It has, on one surface of the frame body is provided with a long stack positioning projection than the thickness of the separator, and the one surface of the frame in which the positioning projections of the pair of the separators is provided The separator Has a larger through-hole than the projection determined, the other separator is a solid polymer electrolyte fuel cell stacking a plurality of unit cells having a hole to be fitted with the positioning projection.

  Thereby, it becomes possible to determine the position by fitting the projection of the frame body integrated with the membrane electrode assembly and the hole of the separator, and the membrane electrode assembly and the separator can be integrated. it can.

  The polymer electrolyte fuel cell of the present invention can relatively accurately position and integrate the membrane electrode assembly and the pair of separators without increasing the number of parts, manufacturing cost, and prolonging the manufacturing lead time. It is possible to provide a polymer electrolyte fuel cell capable of realizing stable sealing performance and output.

The invention according to claim 1 is a membrane electrode assembly comprising a solid polymer electrolyte membrane and a pair of electrodes having a catalytic reaction layer disposed with the solid polymer electrolyte membrane interposed therebetween, and the membrane electrode assembly. A frame body that holds the outer periphery and is integrated with the membrane electrode assembly, and means for supplying a fuel gas containing hydrogen to one of the electrodes of the membrane electrode assembly and an oxidant gas containing oxygen to the other A pair of conductive separators having a plurality of protrusions on a part of the frame, and the separator has at least one unit cell having a hole to be fitted to the protrusions, One surface of the frame body is provided with a stacking positioning protrusion longer than the thickness of the separator, and a separator in contact with the one surface of the frame body provided with the positioning protrusion among the pair of separators. Is the positioning protrusion Also has a large through hole Ri, the other separator is a solid polymer electrolyte fuel cell stacking a plurality of unit cells having a hole to be fitted with the positioning projection. As a result, the membrane electrode assembly and the pair of separators can be relatively accurately positioned and integrated without increasing the number of parts, manufacturing cost, and prolonging the manufacturing lead time, and stable sealing performance and output can be achieved. A solid polymer fuel cell that can be realized can be provided.

  According to a second aspect of the present invention, there is provided a membrane electrode assembly comprising a solid polymer electrolyte membrane and a pair of electrodes having a catalytic reaction layer disposed with the solid polymer electrolyte membrane interposed therebetween, and the membrane electrode assembly. A frame body that holds the outer periphery and is integrated with the membrane electrode assembly, and means for supplying a fuel gas containing hydrogen to one of the electrodes of the membrane electrode assembly and an oxidant gas containing oxygen to the other A pair of conductive separators having a plurality of protrusions each having a key claw-like tip at a part of the frame, and the separator has a plurality of steps corresponding to the protrusions. A polymer electrolyte fuel cell having at least one unit cell having a hole, thereby increasing the number of parts, manufacturing cost, and prolonging the production lead time, and without causing a long lead time of the membrane electrode assembly and a pair of separators And positioning relatively accurately Te can be integrated, it is possible to provide a polymer electrolyte fuel cell capable of realizing a stable sealing performance and output.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, in addition to the protrusions, a stacking positioning protrusion longer than the thickness of the separator is provided on one surface of the frame, and the pair of separators A plurality of integrated cells by having a through-hole larger than the positioning projection in the separator in contact with the positioning projection, and having a hole to be fitted in the positioning projection in the other separator. When stacking, it is relatively easy to regulate the position of each unit cell.

  Thereby, even when a plurality of unit cells are stacked, it is possible to provide a polymer electrolyte fuel cell that realizes stable sealing performance between the unit cells.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited to the embodiments. In addition, about the part same as a prior art example, the same code | symbol is attached | subjected and the description is abbreviate | omitted.

(Embodiment 1)
FIG. 1 is a perspective exploded view of a unit cell of a polymer electrolyte fuel cell according to Embodiment 1 of the present invention, and FIG. 2 is a partial cross-sectional view of a main part of the unit cell.

  As shown in FIG. 1, the cell 1 includes a membrane electrode assembly 105 configured by sandwiching a polymer electrolyte membrane 101 between a pair of electrodes 104, and a membrane electrode assembly 105 formed by insert molding around the membrane electrode assembly 105. The polypropylene frame 2 formed in the above is sandwiched between a pair of anode side separator 3a and cathode side separator 3c. The anode side separator 3a, the cathode side separator 3c, and the frame 2 are provided with a fuel gas inlet manifold 4 for introducing a fuel gas containing hydrogen from the outside, and a fuel gas that has not been used for power generation is discharged to the outside. Fuel gas outlet manifold 5, oxidant gas inlet manifold 6 for introducing oxidant gas containing oxygen from the outside, and oxidant gas outlet manifold for discharging oxidant gas not used for power generation to the outside 7 is provided penetrating in the vicinity of the outer peripheries of the separators 3a and 3c and the frame 2. A gas flow path 8 a for connecting the fuel gas inlet manifold 4 and the fuel gas outlet manifold 5 and supplying fuel gas to the electrode 104 is provided on the surface of the anode separator 3 a that contacts the membrane electrode assembly 105. ing. Similarly, the surface of the cathode-side separator 3 c that contacts the membrane electrode assembly 105 is connected to the oxidant gas inlet manifold 6 and the oxidant gas outlet manifold 7, and a gas flow path 8 c for supplying oxidant gas to the electrode 104. Is provided. The gas flow paths 8 a and 8 c are formed by meandering a plurality of flow paths in order to supply gas to the electrode 104 as uniformly as possible. The fuel gas and the oxidant gas supplied to the unit cell are humidified in order to exert the hydrogen ion conductivity of the polymer electrolyte membrane 101, and the polymer electrolyte membrane 101 is always kept in a wet state. Water vapor generated in the gas condenses or is generated along with power generation accumulates in the gas flow paths 8a and 8c to close the flow path, and is introduced from above and discharged from below so as not to obstruct the gas flow. The gas flow paths 8a and 8c were configured as described above.

  Further, on the gas flow path 8a side of the anode-side separator 3a, a membrane electrode assembly gasket made of fluororubber is considered so that fuel gas does not leak to the outside and oxidant gas and circulating water do not enter this surface. 9a is provided. Similarly, a membrane electrode assembly gasket 9c is provided on the gas flow path 8c side of the cathode side separator 3c in consideration of preventing oxidant gas from leaking to the outside and preventing fuel gas and circulating water from entering this surface. Yes. The membrane electrode assembly gaskets 9a and 9c are compressed by the frame 2 and the separators 3a and 3c to exhibit a sealing property.

  Further, a protrusion 10 having a height less than or equal to the thickness of the separators 3a and 3c is formed in the vicinity of the outer periphery of the frame 2, and a hole into which the protrusion 10 is press-fitted into a position corresponding to the protrusion 10 is formed in the separators 3a and 3c. 11 is formed.

  Note that a plurality of protrusions 10 and holes 11 are provided so as to be positioned outside the membrane electrode assembly gaskets 9a and 9c, and the tip of the protrusion 10 is chamfered at the tip.

  In addition, since the output of the unit cell 1 is small, it is necessary to stack a plurality of the unit cells 1 in series in order to obtain the necessary electric and heat output, but the anode side separator 3a and the cathode side separator 3c, The frame 2 is opposite to the surface in contact with the membrane electrode assembly 105 of the anode side separator 3a and the cathode side separator 3c for circulating water for removing heat generated with power generation when a plurality of unit cells 1 are stacked. A circulating water inlet manifold 13 and a circulating water outlet manifold 14 for introducing into and discharging from the circulating water channel 12 formed on the surface are provided in the vicinity of the outer periphery, and are provided on the circulating water channel 12 side of the cathode side separator 3c. A separator gasket 15 is provided on the surface so that circulating water does not leak to the outside and oxidant gas and fuel gas do not enter the surface. There.

  Further, at the four corners of the separators 3a and 3c and the frame body 2, when a plurality of unit cells 1 are stacked, through holes 16 through which a plurality of unit cells are integrated and a fastening rod for applying a fastening force is passed are membrane electrode junctions. The body gaskets 9a and 9c and the separator gasket 15 are provided so as to be positioned outside.

  The operation of the polymer electrolyte fuel cell configured as described above will be described below.

  A unit cell 1 is formed by sandwiching the membrane electrode assembly 105 and the frame body 2 together with a pair of separators 3a and 3c. At that time, a fastening force is applied from both sides of the separators 3a and 3c. Thus, the projection 10 of the frame body 2 is press-fitted into the holes 11 of the separators 3a and 3c.

  Thereby, the membrane electrode assembly 105, the frame 2, and the separators 3a and 3c are integrated.

  Further, by integrating the membrane electrode assembly 105 with the frame body 2, it is easy to position the membrane electrode assembly 105 with respect to the separators 3 a and 3 c when the unit cell 1 is assembled. The positional relationship between the gas flow paths 8a and 8c and the electrode 104 and the positional relationship between the membrane electrode assembly gaskets 9a and 9c and each manifold can be accurately regulated by the holes 10 and the holes 11.

  Furthermore, since the membrane electrode assembly gaskets 9a and 9c are sandwiched between the frame body 2 and the separators 3a and 3c, which are relatively hard, the sealing performance can be improved as compared with sandwiching between the membrane electrode assembly and the separator.

(Embodiment 2)
FIG. 3 is an exploded perspective view of the unit cell of the polymer electrolyte fuel cell according to Embodiment 2 of the present invention, and FIG. 4 is a partial cross-sectional view of the main part of the unit cell.

  As shown in FIGS. 3 and 4, the polymer electrolyte fuel cell according to the present embodiment includes the shape of the protrusion of the polymer electrolyte fuel cell shown in Embodiment 1 and the shape of the hole into which the protrusion is fitted. However, it differs from the previous embodiment in that the tip 17 is a key-like protrusion 17 and a stepped hole 18.

  With this configuration, when the membrane electrode assembly 105 and the frame body 2 and the pair of separators 3a and 3c are combined and pressed in the stacking direction, the tip key-like portion of the protrusion 17 fits into the stepped hole 18. Accordingly, the membrane electrode assembly 105, the frame body 2, and the separators 3a and 3c can be integrated with each other with an accurate positional relationship.

  Furthermore, since the integrated product of the membrane electrode assembly 105 and the frame 2 and the separators 3a and 3c can be easily disassembled, maintenance performance such as replacement of the membrane electrode assembly 105 and replacement of the separators 3a and 3c can be improved. Improvement is possible.

(Embodiment 3)
FIG. 5 is a perspective exploded view of a unit cell of a polymer electrolyte fuel cell according to Embodiment 3 of the present invention, and FIG. 6 is a partial cross-sectional view of the main part when two unit cells are stacked.

  As shown in FIGS. 5 and 6, the polymer electrolyte fuel cell according to the present embodiment has a cathode on the surface in contact with the cathode-side separator 3c of the frame 2 in addition to the protrusions and holes shown in the previous embodiment. A positioning projection 19 longer than the thickness of the side separator 3c and reaching the anode side separator 3a of the adjacent unit cell 1, a through hole 20 through which the positioning projection 19 penetrates the cathode side separator 3c, and an anode side separator It differs from the polymer electrolyte fuel cell of the previous embodiment in that a fitting hole 21 into which the positioning projection 19 is fitted is provided in 3a.

  Thereby, when a plurality of unit cells 1 in which the integral product of the membrane electrode assembly 105 and the frame 3 and the separators 3 a and 3 c are integrated, the positioning protrusions 19 constitute the cathodes constituting the unit cell 1. By passing through the through-hole 20 of the side separator 3c and fitting into the fitting hole 21 of the anode-side separator 3a of the adjacent unit cell 1, it is possible to stack a plurality of unit cells without shifting their positional relationship. It is.

  As described above, the polymer electrolyte fuel cell according to the present invention can be applied to uses such as a portable power source, a power source for an electric vehicle, and a stationary cogeneration system.

1 is an exploded perspective view of a unit cell of a polymer electrolyte fuel cell according to Embodiment 1 of the present invention. FIG. Cross section of the main part of the cell of the same embodiment The perspective exploded view of the unit cell of the polymer electrolyte fuel cell in Embodiment 2 of this invention Cross section of the main part of the cell of the same embodiment The perspective exploded view of the unit cell of the polymer electrolyte fuel cell in Embodiment 3 of this invention Cross-sectional view of the main part of a polymer electrolyte fuel cell in which two unit cells of the same embodiment are stacked Disassembled cross-sectional view of a conventional unit cell of a polymer electrolyte fuel cell

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cell 2 Frame 3a Anode side separator 3c Cathode side separator 4 Fuel gas inlet manifold 5 Fuel gas outlet manifold 6 Oxidant gas inlet manifold 7 Oxidant gas outlet manifold 8a, 8c Gas flow path 9a, 9c Membrane electrode assembly gasket DESCRIPTION OF SYMBOLS 10 Protrusion 11 Hole 12 Circulating water flow path 13 Circulating water inlet manifold 14 Circulating water outlet manifold 15 Separator gasket 16 Through hole 17 Protrusion 18 Stepped hole 19 Positioning protrusion 20 Through hole 21 Fitting hole 101 Polymer electrolyte membrane (solid polymer Electrolyte membrane)
104 electrode 105 membrane electrode assembly

Claims (3)

A membrane electrode assembly comprising a solid polymer electrolyte membrane and a pair of electrodes having a catalytic reaction layer disposed with the solid polymer electrolyte membrane interposed therebetween;
A frame that holds the outer periphery of the membrane electrode assembly and is integrated with the membrane electrode assembly;
A pair of conductive separators having means for supplying a fuel gas containing hydrogen to one of the electrodes of the membrane electrode assembly and supplying an oxidant gas containing oxygen to the other;
Have
A part of the frame has a plurality of protrusions, and the separator has at least one unit cell having a hole to be fitted with the protrusions,
One surface of the frame body is provided with a stacking positioning protrusion longer than the thickness of the separator, and a separator in contact with the one surface of the frame body provided with the positioning protrusion among the pair of separators. Has a through-hole larger than the positioning projection, and the other separator is laminated with a plurality of unit cells having holes that fit into the positioning projection.
Solid polymer fuel cell. A membrane electrode assembly having a solid polymer electrolyte membrane and a pair of electrodes having a catalytic reaction layer arranged with the solid polymer electrolyte membrane interposed therebetween, and holding the outer periphery of the membrane electrode assembly, the membrane electrode assembly And a pair of conductive separators having means for supplying a fuel gas containing hydrogen to one of the electrodes of the membrane electrode assembly and supplying an oxidant gas containing oxygen to the other And
A solid polymer fuel having at least one unit cell having a plurality of protrusions each having a key claw-like tip at a part of the frame, and having a plurality of stepped holes corresponding to the protrusions in the separator. battery. One surface of the frame body is provided with a stacking positioning protrusion longer than the thickness of the separator, and a separator in contact with the one surface of the frame body provided with the positioning protrusion among the pair of separators. 3. The solid height according to claim 2, wherein a plurality of unit cells having a through hole larger than the positioning projection and having a hole fitted to the positioning projection are stacked on the other separator. Molecular fuel cell.

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