JP2010086668A - Fuel cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an easy-to-manufacture and low cost solid polymer type fuel cell. <P>SOLUTION: Each of single cells constituting a stack of the fuel cell includes a solid polymer film 20, an anode catalyzer layer 21 and a cathode catalyzer 22 sandwiching the film, an anode gas diffusion layer 23 and a cathode gas diffusion layer 24 sandwiching the above and separators 3 sandwiching the above. A fuel gas flow path groove 8 is formed in a surface of the separator 3 facing the layer 23 and an oxidant gas flow path groove 7 is formed in a surface of the separator 3 facing the layer 24. Seal members 2 are fitted on both the sides of the separator 3 to sandwich the separator. The seal members 2 wrap at least each two corners of both the surfaces of the separator 3 to cover parts of both the surfaces of the separator 3 except the grooves 8, 7. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a fuel cell in which unit cells using a solid polymer film as an electrolyte layer are stacked, and more particularly to a fuel cell with improved assembly workability.

  A fuel cell is a device in which a catalyst layer is disposed on both sides of an electrolyte layer, and fuel and an oxidant are supplied to the catalyst layer to generate electricity by an electrochemical reaction. For example, in a general polymer electrolyte fuel cell, a catalyst layer made of platinum or a platinum compound and a gas diffusion layer made of porous carbon paper or the like are formed on both sides of a solid polymer membrane formed of an ion exchange membrane. It has a structure in which gas-impermeable separators are provided which are laminated and further have gas supply flow paths and cooling water flow paths for supplying cooling water for removing heat generated by power generation on both sides. . In addition, a seal portion for preventing gas and cooling water from flowing out from a predetermined flow path to the outside is provided between the laminated surfaces of the members.

  Here, as a sealing method between the laminated surfaces, a method of melting a thermoplastic polymer having a predetermined shape and bonding each member, and a method of sandwiching an elastic seal member having a predetermined shape have been proposed (for example, patents). Reference 1).

Also, as a method of simplifying the installation of the seal member by sandwiching a resilient seal member between the seals between the laminated surfaces, the seal members on both sides of the separator are connected and the cross section of the seal member is molded into a concave shape, There has been proposed a method of assembling a gasket by fitting a concave seal member and a convex separator end (see, for example, Patent Document 2).
JP-T-2004-523060 JP 2002260692 A

  However, in the case of using a separator formed so that the gas supply flow path reaches a part of the outer periphery of the separator, the method of sandwiching the elastic seal member according to Patent Document 1 uses the gas supply flow path. It is necessary to install a seal member avoiding the portion reaching the outer periphery of the separator. Generally, the surface of the separator on which the fuel gas channel groove is formed is 2 along the flow direction of the fuel gas channel. Since seal members are installed on the sides and two sides along the flow direction of the oxidant gas flow channel on the surface where the oxidant gas flow channel groove is formed, a total of four independent seal members are provided for each separator. It is necessary to install a sheet. At this time, since the sealing member is an elastic body, it is deformed relatively easily, and since the weight is small, the sealing member moves relatively easily during work, and the sealing member is installed at a predetermined position. It was difficult to work.

  In addition, there is a method of restricting the movement of the sealing member by adhering it to the separator in advance, but in this case, an additional cost for purchasing the adhesive and an operating cost for the adhering work are required, and the entire fuel cell is manufactured. There is a problem that the cost is increased and the material used for adhesion is eluted to lower the performance of the fuel cell.

  In addition, as described above, the method of assembling the gasket by connecting the seal members on both sides of the separator, molding the cross section of the seal member into a concave shape, and fitting the concave portion of the seal member and the convex portion of the separator end is as described above. When a separator formed so that the supply channel reaches a part on the outer periphery of the separator is used, the gas channel groove on the outer periphery of the separator is blocked by the concave seal member. It is impossible.

  The present invention has been proposed in order to solve the above-described problems of the prior art, and an object thereof is to provide a solid polymer fuel cell that is easy to manufacture and low in cost.

  In order to achieve the above object, a fuel cell according to the present invention comprises a solid polymer membrane as an electrolyte layer, an anode catalyst layer and a cathode catalyst layer disposed so as to sandwich the solid polymer membrane from both sides thereof, An anode gas diffusion layer and a cathode gas diffusion layer disposed so as to be in contact with and sandwiching the anode catalyst layer and the cathode catalyst layer, respectively, and an anode gas diffusion layer and a cathode gas diffusion layer are disposed between the anode catalyst diffusion layer and the cathode gas diffusion layer. A planar gas-impermeable separator that forms a fuel gas flow channel at a position facing the anode gas diffusion layer and an oxidant gas flow channel at a position facing the cathode gas diffusion layer; The separator and the anode gas diffusion layer are opposed to each other and the separator and the cathode gas diffusion layer are opposed to each other. It is arranged so as to be embedded, and is configured to wrap around at least two corners on both sides of the separator and to cover portions on both sides of the separator excluding the fuel gas passage groove and the oxidant gas passage groove. And a laminated body in which a plurality of unit cells having a sealing member made of an elastic material are laminated.

  According to the present invention, the sealing member between the laminated surfaces can be easily attached to the separator, and further, it is not necessary to take measures to prevent the sealing member from moving by, for example, bonding the sealing member to the separator or other members in advance. Therefore, a fuel cell with a low manufacturing cost can be provided.

  Embodiments of the present invention will be described below with reference to the drawings.

[First Embodiment]
A first embodiment of a fuel cell according to the present invention will be described with reference to FIGS.

  FIG. 1 is a developed perspective view showing a laminated body of a first embodiment of a fuel cell according to the present invention, FIG. 2 is an elevation view showing an assembled state of the laminated body of FIG. 1, and FIG. 3 is a membrane electrode composite of FIG. It is a typical partial expanded sectional view of a body. 4 is a perspective view showing the fuel cell according to the first embodiment, and FIG. 5 is a plan sectional view of the fuel cell of FIG. 6 is a perspective view of the separator and the seal member of FIG. 1 viewed from the fuel gas flow channel groove side, FIG. 7 is a perspective view of the separator of FIG. 1 viewed from the oxidant gas flow channel side, and FIG. 1 is a perspective view of the separator 1 viewed from the fuel gas flow channel groove side, FIG. 9 is a perspective view of the seal member of FIG. 1 viewed from the oxidant gas flow channel groove side, and FIG. 10 is a perspective view of the seal member of FIG. It is the perspective view seen from the road groove side.

  As shown in FIGS. 1 and 4, the fuel cell of this embodiment includes a rectangular or square membrane electrode assembly (MEA) 1 and a rectangular or square flat plate separator 3 made of a gas-impermeable material. The laminated body 4 which laminated | stacked alternately is provided. Moreover, the sealing member 2 is installed on both surfaces of each separator 3. The combination of the membrane electrode assembly 1 and the separator 3 is called a single cell, and the laminate 4 can be said to be a laminate of single cells.

  As shown in FIGS. 4 and 5, an oxidant-based gas manifold 5 and a fuel-based gas manifold 6 are installed around the laminated body 4. Here, each of the oxidant gas manifold 5 and the fuel gas manifold 6 is a box-shaped structure that is adjacent to the laminate 4 and has an opening with respect to the laminate 4, and the oxidant gas inlet pipe 30 and the fuel. An oxidant gas and a fuel gas are respectively supplied to the laminate 4 from the outside via the gas inlet pipe 31. Similarly, the gas that has not been consumed in the stacked body 4 is discharged to the outside through the oxidant gas outlet pipe 32 and the fuel gas outlet pipe 33.

  In the configuration shown in the figure, the internal space of the oxidant-based gas manifold 5 is divided into two by a partition plate 5a, and one space constitutes a flow path for supplying or discharging oxidant gas, and the other space is a laminate. The membrane electrode assembly 4 of No. 4 constitutes a flow path through which cooling water for removing heat generated by power generation flows. The cooling water is supplied from the outside through the cooling water inlet pipe 34 and the cooling water outlet pipe 35 and is discharged after being used for cooling the laminate 4.

  Fastening plates 36 are disposed on both end faces of the laminate 4, and the fastening plates 36 are fastened in a direction approaching each other by tie rods 37.

  As shown in FIG. 3, the membrane electrode assembly 1 has a pair of an anode catalyst layer 21 and a cathode catalyst layer 22 on both sides of a solid polymer membrane 20 that is an electrolyte layer so as to sandwich the solid polymer membrane 20. A pair of gas diffusion layers including an anode gas diffusion layer 23 and a cathode gas diffusion layer 24 are disposed so as to sandwich the anode catalyst layer 21 and the cathode catalyst layer 22.

  As shown in FIGS. 1, 2, and 5 to 8, an oxidant gas passage groove 7 and a fuel gas passage groove 8 are formed on both surfaces of the separator 3, respectively. A cooling water passage 9 is formed through the inside.

  The seal member 2 is made of an elastic material, and is configured such that each seal member 2 integrally wraps both surfaces of one separator 3 as shown in FIGS. 1, 6, 9, and 10. However, the fuel gas channel groove 8 and the oxidant gas channel groove 7 formed on the surface of the separator 3 are configured not to be covered with the seal member 2.

  The seal member 2 is installed along the oxidant gas flow channel groove 7 of the separator 3 to prevent the oxidant gas from leaking to parts other than the oxidant flow passage of the oxidant gas manifold 5. 2a, a fuel system seal portion 2b installed along the fuel gas flow channel groove 8 of the separator 3 to prevent the fuel gas from leaking into a portion other than the fuel flow passage of the fuel system gas manifold 6, and four separators And a seal member connecting portion 2c for connecting the oxidant seal portion 2a and the fuel seal portion 2b.

  The seal member connecting portion 2c is sandwiched between the oxidant gas manifold 5, the fuel gas manifold 6, and the separator 3, and the gas flowing through the oxidant gas manifold 5 and the fuel gas manifold 6 is exposed to the outside. Prevents leakage. Further, in this figure, a seal portion 2d of the partition plate is formed at a position sandwiched between the partition plate 5a of the oxidant gas manifold 5 and the separator 3 in the seal member 2, and between the cooling water system and the oxidant gas system. This prevents the gas and cooling water from moving. The illustrated seal member connection portion 2c covers both sides of the four corners and the entire portion connecting both sides.

  In the illustrated example, each part of the sealing member 2 is made of a rectangular parallelepiped or a combination thereof, and the cross section of each part is made of a rectangle or a combination thereof.

  Here, the oxidant seal part 2a, the fuel seal part 2b, the seal member connection part 2c, and the seal part 2d of the partition plate can be manufactured by adhering separately molded products. Considering the cost of molding and bonding, it is desirable to mold as a single piece from the beginning. Further, as the material of the seal member 2, EPDM (ethylene propylene diene rubber), silicon rubber, or the like can be applied. However, the seal member 2 is a material that does not affect the operation of the fuel cell due to a decrease in sealability and elution from the material. Any other single material or a combination of materials may be used.

  Next, the operation of the first embodiment having the above configuration will be described. In the first embodiment having the above-described configuration, when the separator 3 and the seal member 2 are viewed from the direction of the fuel gas manifold 6, the left and right ends of the oxidant seal portion 2 a are connected to the seal member connection portion 2 c and The end portion of the fuel system seal portion 2b is connected, and has a shape that is folded back so as to wrap around the end portion of the separator 3 facing the fuel system gas manifold 6. Accordingly, when viewed from the direction of the fuel gas manifold 6, the seal member 2 installed on the separator 3 cannot move in the vertical and horizontal directions.

  Similarly, when the separator 3 and the seal member 2 are viewed from the direction of the oxidant gas manifold 5, the left and right ends of the fuel system seal portion 2b are connected to the seal member connection portion 2c and the oxidizer seal portion 2a. The end portion is connected, and the shape of the separator 3 is folded so as to wrap around the side of the end portion facing the oxidant gas manifold 5. Therefore, when viewed from the direction of the oxidant-based gas manifold 5, the seal member 2 installed in the separator 3 cannot move in the vertical and horizontal directions as well.

  Therefore, the seal member 2 is installed in the separator 3 in a state where the seal member 2 cannot move in any direction unless an external force that elastically deforms the seal member 2 is applied. In order to prevent the seal member 2 from moving after installation. It is not necessary to previously adhere the seal member 2 to the separator 3 or the membrane electrode assembly 1.

  Regarding the mounting operation of the seal member 2, since the seal member 2 is made of an elastic body, the seal member 2 is deformed within the range of the elastic deformation, and the portion of the seal member 2 that is folded is separated into the separator. When the four corners 3 are fitted, the seal member 2 returns to its original shape again, and can be installed at a predetermined position without requiring special alignment.

  Further, since the seal member connecting portion 2c of the seal member 2 and the seal portion 2d of the partition plate form a seal portion between the laminate 4, the oxidant gas manifold 5 and the fuel gas manifold 6, a new portion is added to this portion. There is no need to install sealing parts on the

  As described above, in the present embodiment, the seal member 2 is installed on the separator 3 in a state in which it cannot move in any direction, and the seal member 2 is attached to the separator 3 to prevent the seal member 2 from moving after installation. Alternatively, it is not necessary to bond the membrane electrode assembly 1 in advance. Accordingly, there is no need to purchase an adhesive and work costs for the bonding work, and it is not necessary to install a plurality of independent sealing members for each separator 3, and the sealing member 2 requires special alignment. It becomes possible to install in a predetermined position without. Thereby, the purchase cost of seal parts and the installation work time of seal parts are reduced. Moreover, since the problem that the substance used for adhesion elutes and the performance of the fuel cell deteriorates does not occur, an inexpensive and high-performance fuel cell can be provided.

  Further, since the seal member connecting portion 2c of the seal member 2 and the seal portion 2d of the partition plate form a seal portion between the laminate 4, the oxidant gas manifold 5 and the fuel gas manifold 6, a new portion is added to this portion. It is no longer necessary to install a seal part in the battery, and the purchase cost of the seal part and the installation work time of the seal part are reduced, and an inexpensive fuel cell can be provided.

[Second Embodiment]
A first embodiment of the fuel cell according to the present invention will be described with reference to FIGS. 11 and 12. Here, the same or similar components as those in the first embodiment are denoted by common reference numerals, and redundant description is omitted.

  FIG. 11 is a perspective view of the separator and the sealing member in the second embodiment of the fuel cell according to the present invention viewed from the oxidant gas flow channel groove side, and FIG. 12 shows the fuel gas in the separator and the sealing member in the second embodiment. It is the perspective view seen from the channel groove side.

  The second embodiment corresponds to the case where the cooling water flow path 9 in the first embodiment is not formed in the separator 3. In this case, both the oxidant gas passage groove 7 and the fuel gas passage groove 8 are linear and extend in directions orthogonal to each other. In this case, the sealing member 2 does not have a partition plate sealing portion 2d (see FIGS. 1 and 6). Further, in the illustrated example, the sealing member connecting portion 2 c does not completely cover the corner portion of the separator 3, and has a shape in which a plurality of strips extending in a direction perpendicular to the surface of the separator 3 are arranged. Some are exposed. In this manner, the oxidant seal portion 2a, the fuel seal portion 2b, and the seal member connection portion 2c are connected to each other, and the movement of the seal member 2 in each direction with respect to the corner portion of the separator 3 is restricted. If present, the sealing member connecting portion 2 c may not completely cover the corner portion of the separator 3.

[Other Embodiments]
The embodiments described above are merely examples, and the present invention is not limited to these. Moreover, each part structure of this invention is not restricted to the said embodiment, A various deformation | transformation is possible within the technical scope as described in a claim.

  For example, the cross-sectional shape of each part of the sealing member is not limited to a rectangle or a combination thereof, and a circular cross-section may be used partially, a convex part may be provided, or a hollow material may be used.

  The seal member is basically made of an elastic material, but it goes without saying that a material other than the elastic material may be partially used.

  Furthermore, in the said embodiment, although each sealing member becomes a structure which wraps all the corner | angular parts (a total of eight corner | angular parts) of both surfaces of one rectangular separator, each sealing member, If it is the structure which wraps at least two corner | angular parts of both surfaces of one separator integrally, the workability | operativity at the time of an assembly will improve significantly compared with a prior art.

  In particular, if each sealing member is configured to integrally wrap the diagonal corners of both sides of one separator, once the sealing member is attached to the separator, it becomes difficult to come off, so the workability during assembly is improved. Further improve.

  Alternatively, the seal member connecting portion 2c and the seal portion 2d of the partition plate may not be in contact with the oxidant gas manifold 5 and the fuel gas manifold 6.

  In the description of each of the above embodiments, expressions such as a plan view and an elevation view, and expressions such as top and bottom are used for convenience of explanation, and the fuel cell according to the present invention is gravity. It can be arranged regardless of the direction.

FIG. 2 is a developed perspective view showing the laminated body of the first embodiment of the fuel cell according to the present invention. The elevation view which shows the assembly state of the laminated body of FIG. The typical partial expanded sectional view of the membrane electrode assembly of FIG. 1 is a perspective view showing a first embodiment of a fuel cell according to the present invention. FIG. 5 is a plan sectional view of the fuel cell of FIG. 4. The perspective view which looked at the separator and seal member of Drawing 1 from the fuel gas channel slot side. The perspective view which looked at the separator of FIG. 1 from the oxidant gas flow path groove side. The perspective view which looked at the separator of Drawing 1 from the fuel gas channel slot side. The perspective view which looked at the seal member of Drawing 1 from the oxidant gas channel slot side. The perspective view which looked at the seal member of Drawing 1 from the fuel gas channel slot side. The perspective view which looked at the separator and sealing member in 2nd Embodiment of the fuel cell which concerns on this invention from the oxidizing agent gas flow path groove side. The perspective view which looked at the separator and sealing member in 2nd Embodiment of the fuel cell which concerns on this invention from the fuel gas flow-path groove side.

Explanation of symbols

1: Membrane electrode assembly (MEA)
2: Seal member 2a: Oxidant seal part 2b: Fuel seal part 2c: Seal member connection part 2d: Seal part 3 of the partition plate: Separator 4: Stack 5: Oxidant gas manifold 5a: Partition plate 6: Fuel system gas manifold 7: Oxidant gas channel groove 8: Fuel gas channel groove 9: Cooling water channel 20: Solid polymer film 21: Anode catalyst layer 22: Cathode catalyst layer 23: Anode gas diffusion layer 24: Cathode gas Diffusion layer 30: Oxidizing gas inlet pipe 31: Fuel gas inlet pipe 32: Oxidant gas outlet pipe 33: Fuel gas outlet pipe 34: Cooling water inlet pipe 35: Cooling water outlet pipe 36: Clamping plate 37: Tie rod

Claims (5)

A solid polymer film as an electrolyte layer;
An anode catalyst layer and a cathode catalyst layer disposed so as to sandwich the solid polymer membrane from both sides thereof;
An anode gas diffusion layer and a cathode gas diffusion layer disposed in contact with each of the anode catalyst layer and the cathode catalyst layer and sandwiching the catalyst layers; and
The anode gas diffusion layer and the cathode gas diffusion layer are arranged so as to be sandwiched therebetween, a fuel gas flow channel is formed at a position facing the anode gas diffusion layer, and an oxidant gas is positioned at a position facing the cathode gas diffusion layer. A flat, gas-impermeable separator that forms a flow channel groove;
The separator and the anode gas diffusion layer are disposed so as to be opposed to each other and the separator and the cathode gas diffusion layer are disposed so as to be opposed to each other, so as to enclose at least two corners on both surfaces of the separator, A seal member configured to cover portions on both sides of the separator excluding the fuel gas channel groove and the oxidant gas channel groove, and formed of an elastic material;
A fuel cell comprising: a stacked body in which a plurality of single cells having the same structure are stacked.   2. The fuel cell according to claim 1, wherein the seal member is configured so that each seal member is a single member and wraps at least diagonal portions of both surfaces of each separator.   3. The fuel cell according to claim 1, wherein the seal member is configured such that each seal member wraps around each separator alone.   The fuel cell according to any one of claims 1 to 3, wherein a cooling water flow path is formed in at least a part of the separator constituting the laminated body. A fuel system gas manifold disposed along a side surface in the stacking direction of the stacked body, pressed against the periphery of the seal member and sealed to communicate with the fuel gas flow channel groove;
An oxidant-based gas manifold that is disposed along the side surface in the stacking direction of the laminate, pressed against the periphery of the seal member, sealed, and communicated with the oxidant gas passage groove;
The fuel cell according to any one of claims 1 to 4, further comprising:

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