JP5104062B2 - Fuel cell and gas sealing method thereof - Google Patents

Description

  The present invention relates to a fuel cell and a gas sealing method thereof. More specifically, the present invention relates to an improvement in the internal structure of a fuel cell.

  In general, a fuel cell (for example, a polymer electrolyte fuel cell) is composed of an electrolyte membrane and a joined body (eg, MEA) composed of a pair of electrodes disposed on both surfaces thereof, and a pair of separators that sandwich the joined body. . In addition, a plurality of such cells are stacked to form a so-called fuel cell stack.

Conventionally, in such a fuel cell, a seal member such as a gasket is provided between the joined body and the separator or between the separator and the separator in order to suppress gas leakage. For example, a technique or the like in which a sealing member is provided so as to cover the edge portion of each separator and gas is sealed is disclosed (for example, see Patent Document 1).
JP 2004-213930 A

  However, even if the structure is sealed with the sealing member as described above, if there is a gap in the electrode, the gas may flow in a gap that easily flows without passing through the reaction portion of the electrode that should pass through. Then, a part of the reaction gas (oxidizing gas, fuel gas) is not used for the power generation reaction, and there is a possibility that the performance as a fuel cell is not sufficient. Moreover, since the gaps in the electrodes are narrow or have large variations, existing sealing members may not be able to seal sufficiently.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a fuel cell and a gas sealing method thereof that can improve sealing performance by making the sealing of electrodes of the fuel cell easier and more reliable.

  As described above, sufficient sealing performance may not be ensured with existing sealing members. The present inventor, who has earnestly studied this matter, has obtained the following knowledge. That is, for example, gas also passes through the electrode (porous body, diffusion layer) (that is, the edge portion), so that the portion also needs to be sealed, but there is a gap in the side portion. In some cases, some of the gas that would otherwise be used for the power generation reaction flows out into the gap where it easily flows through these porous bodies and diffusion layers (so-called side flow, bypass).

  On the other hand, for example, the porous body and the end portions of the diffusion layer constituting the electrode are not completely aligned, so there is a step, which may cause a very small gap. In addition, since there are variations in the size of the gaps, it is difficult to fill these gaps with an existing seal member such as an O-ring.

  In addition, when the sealing member is sandwiched between separators, the sealing member is interposed between the porous body, the diffusion layer, the catalyst layer, the electrolyte membrane, and the separator, but the amount of the sealing member entering is generally not visible. Therefore, there is a problem that it is difficult to manage the current collection area and the surface pressure. In some cases, it may be difficult to confirm whether or not the seal has been achieved.

  The present inventor, who has further studied focusing on these matters, has come to obtain new knowledge that leads to the solution of such problems. The present invention is based on such knowledge, an electrolyte membrane, a porous support layer provided outside the electrolyte membrane, a separator provided further outside the support layer and partitioning fuel cells, The edge of the support layer protrudes from the edge of the separator, and the edge of the support layer that protrudes from the separator is sealed from the outside.

  The fuel cell gas sealing method according to the present invention includes an electrolyte membrane, a porous support layer provided outside the electrolyte membrane, and a fuel cell provided further outside the support layer. In the fuel cell having a separator, the edge of the support layer protrudes from the edge of the separator, and the edge of the support layer protrudes from the separator is sealed from the outside.

  Thus, in this invention, it is supposed that the fuel cell of the state which a part (edge part) of the support layer protruded from the separator is comprised. In such a case, the portion to be sealed by the seal member, particularly the edge portion of the support layer, is in a so-called exposed state (visible state), so that the sealing operation becomes easier.

  In this invention, the support layer may include a porous body formed larger than the separator and a diffusion layer formed larger than the porous body. In this case, it is preferable that each edge part of an electrolyte membrane, a diffusion layer, and a porous body is formed in step shape. Further, it is more preferable that at least a portion of the porous body and the diffusion layer protruding from the edge of the separator is covered with the sealing member.

  When the support layer includes a porous body and a diffusion layer, the size (size) of each member is increased in the order of “separator <porous body <diffusion layer”. By sticking out, it becomes easier to seal. That is, in the case of such a structure, the porous body and the diffusion layer, which are parts to be sealed, are arranged in a stepped manner in an exposed state, so that the sealing work is extremely easy. In addition, if the exposed portion is sealed from the outside, a narrow gap between the members can be filled with the seal member, so that the sealing performance can be further improved.

  According to the present invention, the sealing of the electrode of the fuel cell becomes easier and more reliable, and the sealing performance can be improved.

  Hereinafter, the configuration of the present invention will be described in detail based on an example of an embodiment shown in the drawings.

  1 to 5 show an embodiment of the present invention. The fuel cell 1 according to the present invention includes an electrolyte membrane 31, catalyst layers 32A and 33A and porous support layers 32B and 33B provided outside the electrolyte membrane 31, and further outside the support layers 32B and 33B. And a separator 20 (20a, 20b) that is provided and partitions the fuel cells 2 from each other. Furthermore, in the fuel cell 1 according to the present embodiment, the edge portions of the support layers 32B and 33B protrude from the edge of the separator 20, and the edge portions of the support layers 32B and 33B protrude from the separator 20 from the outside. It is sealed.

  In the embodiment described below, first, a schematic configuration of a fuel cell stack in which a cell (power generation cell) 2 and a plurality of cells 2 constituting the fuel cell 1 are stacked will be described, and then the support layers 32B and 33B. A structure for sealing the edge of the outer side will be described.

  FIG. 1 shows a schematic configuration of a cell 2 of a fuel cell 1 in the present embodiment. The cells 2 configured as shown in the figure are sequentially stacked to form a cell stack 3 (see FIG. 2). Further, in the fuel cell stack composed of the cell stack 3 or the like, for example, both ends of the stack are sandwiched between a pair of end plates 7, and a restraining member including a tension plate 8 is disposed so as to connect the end plates 7 to each other. In this state, a load in the stacking direction is applied and fastened (see FIG. 2).

  The fuel cell 1 configured by such a fuel cell stack or the like can be used in, for example, an in-vehicle power generation system of a fuel cell vehicle (FCHV; Fuel Cell Hybrid Vehicle), but is not limited thereto. It can also be used in power generation systems mounted on various mobile bodies (for example, ships, airplanes, etc.), self-propelled devices such as robots, and stationary power generation systems.

  As an electrolyte contained in the cell 2, a membrane-electrode assembly (MEA) or a membrane-electrode-diffusion layer assembly (MEGA) can be used. For example, in this embodiment, a membrane-electrode-diffusion layer assembly (hereinafter also referred to as MEGA) 30 is used (see FIG. 1 and the like).

  The cell 2 includes a MEGA 30 and a pair of separators 20 (indicated by reference numerals 20a and 20b in FIG. 1 and the like) that sandwich the MEGA 30 (see FIG. 1). The MEGA 30 and the separators 20a and 20b are formed in a substantially rectangular plate shape. The MEGA 30 is formed so that its outer shape is smaller than the outer shapes of the separators 20a and 20b.

  The MEGA 30 includes a polymer electrolyte membrane (hereinafter also simply referred to as an electrolyte membrane) 31 made of a polymer material ion exchange membrane, and a pair of electrodes (an anode side diffusion electrode and a cathode side diffusion electrode) sandwiching the electrolyte membrane 31 from both sides. 32 and 33 (see FIG. 1). The electrolyte membrane 31 is formed larger than the electrodes 32 and 33. The electrodes 32 and 33 are joined to the electrolyte membrane 31 by, for example, a hot press method with the peripheral edge 34 left.

  The electrodes 32 and 33 constituting the MEGA 30 are made of, for example, porous carbon materials (diffusion layers 32b and 33b) carrying a catalyst such as platinum attached to the surface thereof. One electrode (anode) 32 is supplied with hydrogen gas as a fuel gas (reactive gas), and the other electrode (cathode) 33 is supplied with an oxidizing gas (reactive gas) such as air or an oxidizing agent. An electrochemical reaction is generated in the MEGA 30 by the gas, so that an electromotive force of the cell 2 can be obtained.

  The separator 20 (20a, 20b) is made of a gas impermeable conductive material. Examples of the conductive material include carbon and a hard resin having conductivity, and metals such as aluminum and stainless steel. The base material of the separator 20 (20a, 20b) of the present embodiment is formed of a plate-like metal (metal separator), and a film with excellent corrosion resistance is provided on the surface of the base material on the electrode 32, 33 side. (For example, a film formed by gold plating) is formed.

  Further, a groove-like flow path constituted by a plurality of concave portions is formed on both surfaces of the separators 20a and 20b. These flow paths can be formed by press molding in the case of the separators 20a and 20b of the present embodiment in which the base material is formed of, for example, a plate-like metal. The groove-like flow path formed in this way constitutes a gas flow path 35 for oxidizing gas, a gas flow path 36 for hydrogen gas, or a cooling water flow path 37. More specifically, a gas channel 36 for hydrogen gas is formed on the inner surface of the separator 20a on the electrode 32 side, and a cooling water channel 37 is formed on the back surface (outer surface) ( (See FIG. 1). Similarly, an oxidizing gas flow channel 35 is formed on the inner surface of the separator 20b on the electrode 33 side, and a cooling water flow channel 37 is formed on the back surface (outer surface) (see FIG. 1). . For example, in the case of the present embodiment, regarding the two adjacent cells 2, 2, when the outer surface of the separator 20 a of one cell 2 and the outer surface of the separator 20 b of the cell 2 adjacent to this are combined, The channel 37 is integrated to form a channel having a rectangular or honeycomb cross section.

  Furthermore, as described above, the separators 20a and 20b have a relationship in which at least the uneven shape for forming a fluid flow path is reversed between the front surface and the back surface. More specifically, in the separator 20a, the back surface of the convex shape (convex rib) forming the hydrogen gas gas flow path 36 is a concave shape (concave groove) forming the cooling water flow path 37, and the gas flow path The back surface of the concave shape (concave groove) forming 36 is a convex shape (convex rib) forming the cooling water channel 37. Further, in the separator 20 b, the back surface of the convex shape (convex rib) that forms the gas flow path 35 of the oxidizing gas has a concave shape (concave groove) that forms the cooling water flow path 37, and the concave that forms the gas flow path 35. The back surface of the shape (concave groove) is a convex shape (convex rib) forming the cooling water channel 37.

  Further, in the vicinity of the longitudinal ends of the separators 20a and 20b (in the case of this embodiment, in the vicinity of one end shown on the left side in FIG. 1), the manifold 15a on the inlet side of the oxidizing gas, hydrogen gas An outlet side manifold 16b and a cooling water inlet side manifold 17a are formed. For example, in the case of this embodiment, these manifolds 15a, 16b, and 17a are formed by substantially rectangular or trapezoidal holes provided in the respective separators 20a and 20b, or long and thin rectangular through holes having semicircular ends (FIG. 1). Etc.). Further, an oxidizing gas outlet side manifold 15b, a hydrogen gas inlet side manifold 16a, and a cooling water outlet side manifold 17b are formed at opposite ends of the separators 20a and 20b. In the case of this embodiment, these manifolds 15b, 16a, and 17b are also formed by a substantially rectangular or trapezoidal shape, or a long and narrow rectangular through hole having semicircular ends (see FIG. 1).

  Of the manifolds as described above, the inlet side manifold 16a and the outlet side manifold 16b for the hydrogen gas in the separator 20a are connected via the inlet side communication passage 61 and the outlet side communication passage 62 formed in the separator 20a. Each communicates with a gas flow path 36 for hydrogen gas. Similarly, the inlet side manifold 15a and the outlet side manifold 15b for the oxidizing gas in the separator 20b are each formed of an oxidizing gas via an inlet side connecting passage 63 and an outlet side connecting passage 64 formed in the separator 20b. It communicates with the flow path 35 (see FIG. 1). Further, the inlet side manifold 17a and the outlet side manifold 17b of the cooling water in each separator 20a, 20b are respectively connected via an inlet side communication passage 65 and an outlet side communication passage 66 formed in each separator 20a, 20b. It communicates with the cooling water flow path 37. With the configuration of the separators 20a and 20b as described above, the cell 2 is supplied with oxidizing gas, hydrogen gas, and cooling water. As a specific example, when the cells 2 are stacked, for example, hydrogen gas passes from the inlet side manifold 16a of the separator 20a through the communication passage 61 and flows into the gas flow path 36, and is supplied to the MEGA 30 for power generation. After that, the fluid passes through the communication passage 62 and flows out to the outlet side manifold 16b.

  In the present embodiment, the cooling water inlet side manifold 17a and the outlet side manifold 17b are arranged on one side and on the other side of the separator 20 in the cooling water flow direction, respectively (see FIG. 1). That is, in this embodiment, the inlet side manifold 17a and the outlet side manifold 17b of the cooling water are arranged on the diagonal line of the separator 20 so that the cooling water can easily spread over the separator 20 over the entire surface. .

  The first seal member 13a and the second seal member 13b are provided as necessary (see FIG. 1). When provided between the separators 20a and 20b, the first seal member 13a and the second seal member 13b are, for example, both a plurality of members (for example, four independent small rectangular frames to form a fluid flow path. (See FIG. 1). Among these, the first seal member 13a is provided between the MEGA 30 and the separator 20a. More specifically, a part of the first seal member 13a is a peripheral portion 34 of the electrolyte membrane 31 and a gas flow path 36 of the separator 20a. It is provided so that it may interpose between the surrounding parts. Further, the second seal member 13b is provided between the MEGA 30 and the separator 20b. More specifically, a part of the second seal member 13b includes the peripheral edge 34 of the electrolyte membrane 31 and the gas flow path 35 of the separator 20b. It is provided so as to be interposed between the surrounding portions.

  Further, a plurality of members (for example, four independent small rectangular frames and a large frame for forming a fluid flow path) are formed between the separators 20b and 20a of the adjacent cells 2 and 2. A third seal member 13c is provided (see FIG. 1). The third seal member 13c is provided so as to be interposed between a portion around the cooling water passage 37 in the separator 20b and a portion around the cooling water passage 37 in the separator 20a, and seals between them. It is.

  In addition, as the first to third seal members 13a to 13c, an elastic body (gasket) that seals a fluid by physical contact with an adjacent member, or an adhesive that is bonded by chemical bonding with an adjacent member. An agent or the like can be used. For example, in this embodiment, a member that is physically sealed by elasticity is employed as each of the seal members 13a to 13c, but instead, a member that is sealed by a chemical bond such as the adhesive described above may be employed.

  The frame-like member 40 is a member made of, for example, resin (hereinafter also referred to as a resin frame) that is sandwiched between the separators 20a and 20b together with the MEGA 30. For example, in the present embodiment, a thin frame-shaped resin frame 40 is interposed between the separators 20a and 20b, and at least a part of the MEGA 30 such as a portion along the peripheral edge 34 is sandwiched from the front side and the back side by the resin frame 40. I have to. The resin frame 40 provided in this way functions as a spacer between the separators 20 (20a, 20b) that supports the fastening force, functions as an insulating member, and as a reinforcing member that reinforces the rigidity of the separator 20 (20a, 20b). Demonstrate the function.

  Next, the configuration of the fuel cell 1 will be briefly described (see FIG. 2). The fuel cell 1 according to the present embodiment includes a cell stack 3 formed by stacking a plurality of cells 2, and sequentially heat-insulating cells outside the cells (end cells) 2 and 2 located at both ends of the cell stack 3. 4 and a terminal plate 5 with an output terminal 5a, an insulator (insulating plate) 6, and an end plate 7. A predetermined compressive force in the stacking direction is applied to the cell stack 3 by a tension plate 8 that is bridged so as to connect both end plates 7. Further, a pressure plate 9 and a spring mechanism 9a are provided between the end plate 7 on one end side of the cell stack 3 and the insulator 6, so that the fluctuation of the load acting on the cell 2 is absorbed. ing.

  The heat insulation cell 4 has a heat insulation layer formed of, for example, two separators and a seal member, and plays a role of suppressing heat generated by power generation to be radiated to the atmosphere. That is, in general, the temperature of the end portion of the cell stack 3 is likely to be lowered by heat exchange with the atmosphere, and thus heat exchange (heat dissipation) is suppressed by forming a heat insulating layer at the end of the cell stack 3. Has been done. As such a heat insulating layer, for example, there is a structure in which a heat insulating member 10 such as a conductive plate is sandwiched between a pair of separators similar to those in the cell 2 instead of the membrane-electrode assembly. The heat insulating member 10 used in this case is more suitable as it has better heat insulating properties. Specifically, for example, a conductive porous sheet or the like is used. Moreover, an air layer is formed by sealing the circumference | surroundings of such a heat insulation member 10 with a sealing member.

  The terminal plate 5 is a member that functions as a current collecting plate, and is formed in a plate shape from a metal such as iron, stainless steel, copper, or aluminum. The surface of the terminal plate 5 on the heat insulating cell 4 side is subjected to a surface treatment such as a plating treatment, and the contact resistance with the heat insulating cell 4 is ensured by the surface treatment. Examples of the plating include gold, silver, aluminum, nickel, zinc, tin, and the like. For example, in this embodiment, tin plating is performed in consideration of conductivity, workability, and low cost.

  The insulator 6 is a member that functions to electrically insulate the terminal plate 5 from the end plate 7 and the like. In order to fulfill such a function, the insulator 6 is formed in a plate shape from a resin material such as polycarbonate.

  The end plate 7 is formed in a plate shape with various metals (iron, stainless steel, copper, aluminum, etc.) like the terminal plate 5. For example, in the present embodiment, the end plate 7 is formed using copper, but this is merely an example, and the end plate 7 may be formed of another metal.

  The tension plate 8 is provided so as to bridge between the end plates 7 and 7 and is disposed so that, for example, a pair is opposed to both sides of the cell stack 3 (see FIG. 2). The tension plate 8 is fixed to the end plates 7 and 7 with bolts or the like, and maintains a state in which a predetermined fastening force (compression force) is applied in the stacking direction of the single cells 2. An insulating film is formed on the inner surface of the tension plate 8 (the surface facing the cell stack 3) in order to prevent leakage or sparks. Specifically, the insulating film is formed by, for example, an insulating tape attached to the inner surface of the tension plate 8 or a resin coating applied so as to cover the surface.

  Next, the seal structure at or near the edges of the support layers 32B and 33B of the fuel cell 1 will be described (see FIG. 3 and the like).

  In this embodiment, the electrodes 32 and 33 of the fuel cell 1 are structured to seal the edges of the support layers 32B and 33B from the outside in order to make the sealing of the electrodes 32 and 33 easier and more reliable and improve the sealing performance (FIG. 3 and the like). reference). More specifically, the edges of the support layers 32B and 33B protrude from the edges of the separators 20a and 20b, and the edges of the support layers 32B and 33B protruding from the separators 20a and 20b are sealed from the outside. Like to do.

  Here, the porous support layers 32B and 33B will be described as follows. That is, the support layers 32B and 33B are provided on the outer side of the catalyst layers 32A and 33A provided on both surfaces of the electrolyte membrane 31, and the reaction gas (oxidizing gas, fuel) is supplied to the catalyst layers 32A and 33A. It functions as a gas supply layer for supplying gas. These support layers 32B and 33B and catalyst layers 32A and 33A form electrodes (gas diffusion electrodes) 32 and 33 of the fuel cell 1 (see FIG. 3). The specific structure of the porous support layers 32B and 33B is not particularly limited. For example, in the present embodiment, the gas diffusion layers 32b and 33b and the layered porous bodies 32c and 33c support the support. Layers 32B and 33B are formed (see FIG. 3).

  In the present embodiment, with respect to the size (size) of each member, the porous bodies 32c and 33c are made larger than the separators 20a and 20b, and the gas diffusion layers 32b and 33b are further made larger than the porous bodies 32c and 33c. It is getting bigger. The size of the electrolyte membrane 31 is larger than those of the porous bodies 32c and 33. As described above, in the fuel cell 1 according to the present embodiment, the edge portions of the electrolyte membrane 31, the diffusion layers 32b and 33b, and the porous bodies 32c and 33c reach the edge portions of the separators 20a and 20b. (Refer to the oval portions in FIGS. 3 and 4).

  In such a case, among the diffusion layers 32b and 33b and the porous bodies 32c and 33c, at least a portion protruding from the edges of the separators 20a and 20b and visualized is easily covered with a seal member (indicated by reference numeral 13d in FIG. 3). For this reason, the operation | work required for a seal | sticker becomes very easy (refer FIG. 3 etc.). In addition, in the case of this embodiment in which sealing is performed on the electrodes 32 and 33 whose edges are stepped as described above, a narrow gap that may be generated between the members is formed by the sealing member (for example, a liquid gasket) 13d. Since it is possible or easy to fill, it is possible to block gas outflow and further improve the sealing performance (see FIGS. 5A and 5B).

  That is, in the conventional structure, the support layers (diffusion layers 32b and 33b and porous bodies 32c and 33c) are not stepped as in the present embodiment, and therefore between the separators 20a and 20b. There may be a gap (see FIG. 6). In this case, the reaction gas that would otherwise be used for the chemical reaction (that is, power generation) through the diffusion layers 32b and 33b and the porous bodies 32c and 33c may flow out into the gap where the fuel flows more easily. A so-called side flow of the reaction gas that avoids the power generation reaction portion (indicated by symbol R in FIG. 7) of the battery 1 occurs (see the broken line arrow in FIG. 7), and the power generation performance is not used for power generation due to bypassing. (See FIG. 7).

  In the case of the conventional structure, since the gap to be sealed is not clearly visible, it is difficult to perform the sealing work, and it is also difficult to confirm whether or not the sealing has been performed. In addition, even if the edges of the electrodes 32 and 33 are sealed, a gap remains, and even if the seal member 13d is crushed, it does not enter the gap and may not be sufficiently sealed (see FIG. 8). In addition, if the sealing member 13d is forcibly inserted in such a case, a part of the sealing member 13d enters between the members and affects the current collection area (gas chemical reaction region). The reaction force of the member 13d may affect the surface pressure (the pressure acting between the separator 20 and each member) (see FIG. 9).

  In this respect, as described so far, in this embodiment, the support layers (diffusion layers 32b and 33b and porous bodies 32c and 33c) are visualized as being exposed outside the separators 20a and 20b. It is easy to improve the sealing performance by making the sealing at 32 and 33 easier and more reliable. In addition, since it is not necessary to insert the sealing member 13d inward, it does not affect the current collection area (gas chemical reaction region) or the surface pressure (the pressure acting between the separator 20 and each member) (FIG. (See 5). Furthermore, since it can be realized only by changing the size of the diffusion layers 32b and 33b and the porous bodies 32c and 33c, there is an advantage that no other special device is required.

  Incidentally, if the diffusion layers 32b and 33b and a part of the porous bodies 32c and 33c are protruded outward from the catalyst layers 32A and 33A, the reaction gas is compared with the case where they are not protruded. The passage area (passage region) of the slab increases. However, compared to changes in the gas flow accompanying changes in the shape of the gap, etc., the influence on the uniformity, distribution, flow rate, etc. of the gas flow due to the increase in passage area is small, and there is almost no influence on the power generation performance.

  The above-described embodiment is an example of a preferred embodiment of the present invention, but is not limited thereto, and various modifications can be made without departing from the scope of the present invention. For example, in the present embodiment, the case where the MEGA (membrane-electrode-diffusion layer assembly) 30 is used has been described as an example. However, even if this is an MEA (membrane-electrode assembly), the same effect is realized. Yes.

  In the present embodiment, the uniform support layers 32B and 33B in which the edges of the diffusion layers 32b and 33b and the porous bodies 32c and 33c and the like are arranged substantially linearly are illustrated (see FIG. 3). It is only a suitable example, and the width of the stairs may not necessarily be uniform. In short, it is sufficient that each member is exposed in a state where there is a step so that the sealing is easy and reliable.

It is a disassembled perspective view which shows the structural example of the cell of the fuel cell in this embodiment. It is a side view which shows the structural example of a fuel cell. It is a partial side view of the cell of the fuel cell which shows the concept of this invention. It is the schematic which shows the mode of the flow of the reactive gas in a fuel cell. (A) It is the schematic which compares and shows the sealing material in the clearance gap of a conventional structure, and the (B) sealing material in this invention. It is a partial side view of the fuel cell of the conventional structure for showing the effect of the fuel cell concerning this invention by comparison. It is the outline figure which shows the mode of the side flow of the gas which bypasses the electric power generation reaction part of a fuel cell. It is a partial side view of the fuel cell of conventional structure. It is a partial side view of the fuel cell of conventional structure.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Fuel cell, 2 ... Cell (fuel cell), 13d ... Sealing member, 20 (20a, 20b) ... Separator, 31 ... Polymer electrolyte membrane (electrolyte membrane), 32 ... Anode side diffusion electrode (electrode), 32B 33B ... (porous) support layer, 33 ... cathode side diffusion electrode (electrode), 32b, 33b ... gas diffusion layer (diffusion layer), 32c, 33c ... porous body

Claims (5)

In a fuel cell comprising an electrolyte membrane, a porous support layer provided outside the electrolyte membrane, and a separator provided further outside the support layer and partitioning fuel cell cells,
The fuel cell, wherein an edge of the support layer protrudes from an edge of the separator, and an edge of the support layer protrudes from the separator is sealed from the outside.   The fuel cell according to claim 1, wherein the support layer includes a porous body formed larger than the separator and a diffusion layer formed larger than the porous body.   3. The fuel cell according to claim 2, wherein each of the electrolyte membrane, the diffusion layer, and the porous body has stepped edges.   4. The fuel cell according to claim 2, wherein at least a portion of the porous body and the diffusion layer protruding from an edge of the separator is covered with a sealing member.   For a fuel cell having an electrolyte membrane, a porous support layer provided outside the electrolyte membrane, and a separator provided further outside the support layer and partitioning the fuel cell, the support layer A gas sealing method for a fuel cell, wherein the edge of the support layer protrudes from the edge of the separator, and the edge of the support layer protruding from the separator is sealed from the outside.

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