JP5254771B2 - Fuel cell - Google Patents

Description

  The present invention relates to a fuel cell including a unit cell that sandwiches an electrolyte / electrode structure having a pair of electrodes provided on both sides of an electrolyte with a separator.

  For example, in a polymer electrolyte fuel cell, an electrolyte membrane / electrode structure (an electrolyte / electrode structure) in which an anode electrode and a cathode electrode are disposed on both sides of an electrolyte membrane (electrolyte) made of a polymer ion exchange membrane, respectively. ) (MEA) is provided with a unit cell sandwiched between separators.

  In this case, in the unit cell, when the electrolyte membrane / electrode structure and the separator are integrated, it is necessary to accurately position the electrolyte membrane / electrode assembly and the separator with respect to each other. This is because if the electrolyte membrane / electrode structure deviates from a predetermined position of the separator, the contact resistance may increase and the power generation performance may be degraded, or the reactive gas sealing performance may be degraded.

  Therefore, for example, in the solid polymer electrolyte fuel cell disclosed in Patent Document 1, the MEA 1 is sandwiched between the separators 2 and 3 as shown in FIG. Multiple layers are stacked. The holding device 4 includes a cylindrical body 6 in which a hexagonal head 6a and a groove 6b are formed, and a retaining ring 7 attached to the groove 6b. In the separators 2 and 3, stepped holes 8 a and 8 b for inserting the respective cylindrical bodies 6 are formed at a plurality of locations.

JP-A-8-37012

  However, in the above-mentioned Patent Document 1, a plurality of cylindrical bodies 6 are inserted into the stepped holes 8a and 8b for each single battery body 5 and the retaining ring 7 is attached to the groove 6b of the cylindrical body 6 is necessary. For this reason, when laminating | stacking many cell bodies 5 especially, there exists a problem that said operation | work becomes quite complicated and workability | operativity falls remarkably. In addition, a large number of cylindrical bodies 6 and retaining rings 7 must be prepared, resulting in a problem that the manufacturing cost increases.

  The present invention solves this type of problem, and an object thereof is to provide a fuel cell in which unit cells can be assembled with high accuracy and easily with a simple and economical configuration.

  The present invention relates to a fuel cell including a unit cell that sandwiches an electrolyte / electrode structure having a pair of electrodes provided on both sides of an electrolyte with a separator.

  One separator constituting the unit cell is integrally provided with a positioning pin member on the separator surface, and the other separator constituting the unit cell has a position corresponding to the positioning pin member along the separator stacking direction. In addition, a positioning hole for inserting the positioning pin member is provided.

  Moreover, it is preferable that a positioning pin member has a latching | locking part which penetrates a positioning hole and is latched by another separator.

  Further, the fuel cell includes a plurality of unit cells stacked, and the unit cells adjacent to each other include a positioning pin member provided in one unit cell and a positioning pin member provided in the other unit cell. It is preferable that the positions are shifted from each other in the stacking direction.

  Furthermore, one unit cell is formed with a relief hole at a position corresponding to the positioning pin member provided in the other unit cell along the stacking direction, and the other unit cell has one It is preferable that a relief hole is formed at a position corresponding to the positioning pin member provided in the unit cell along the stacking direction.

  The positioning pin member is preferably formed of a resin material that can be elastically deformed.

  According to the present invention, the unit cell can be positioned and held only by inserting the positioning pin member integrally provided in one separator into the positioning hole provided in the other separator. Therefore, the assembling work of the unit cells is simplified, and the assembling workability is improved at a time when stacking a large number of the unit cells. In addition, since the number of parts is greatly reduced, the manufacturing cost can be reduced favorably. Thereby, the unit cell can be assembled with high accuracy and easily with a simple and economical configuration.

  FIG. 1 is an exploded perspective view of a fuel cell 10 according to the first embodiment of the present invention, and FIG. 2 is a cross-sectional view of the fuel cell 10 taken along line II-II in FIG.

  The fuel cell 10 constitutes a stack in which a plurality of unit cells 12 are stacked in the horizontal direction (arrow A direction). Each unit cell 12 includes an electrolyte membrane / electrode structure (electrolyte / electrode structure) 14, and a cathode side separator 16 and an anode side separator 18 that sandwich the electrolyte membrane / electrode structure 14. The cathode side separator 16 and the anode side separator 18 are made of metal separators, but may be made of carbon separators, for example.

  One end edge of the unit cell 12 in the direction of arrow B communicates with each other in the direction of arrow A to supply an oxidant gas supply communication hole 20a for supplying an oxidant gas, for example, an oxygen-containing gas, and a cooling medium. A cooling medium supply communication hole 22a and a fuel gas discharge communication hole 24b for discharging a fuel gas, for example, a hydrogen-containing gas, are provided.

  The other end edge of the unit cell 12 in the direction of the arrow B communicates with each other in the direction of the arrow A, the fuel gas supply communication hole 24a for supplying the fuel gas, and the cooling medium discharge communication hole for discharging the cooling medium. 22b and an oxidant gas discharge communication hole 20b for discharging the oxidant gas are provided.

  As shown in FIGS. 1 and 2, for example, an oxidant gas flow path 26 extending in the direction of arrow B is provided on the surface 16 a of the cathode separator 16 on the electrolyte membrane / electrode structure 14 side. The oxidant gas flow channel 26 communicates with the oxidant gas supply communication hole 20a and the oxidant gas discharge communication hole 20b. A cooling medium flow path 28 is formed on the surface 16 b opposite to the surface 16 a of the cathode separator 16. The cooling medium flow path 28 communicates with the cooling medium supply communication hole 22a and the cooling medium discharge communication hole 22b.

  On the surface 18a of the anode separator 18 on the electrolyte membrane / electrode structure 14 side, there is a fuel gas passage 30 that communicates with the fuel gas supply communication hole 24a and the fuel gas discharge communication hole 24b and extends in the direction of arrow B. It is formed. The fuel gas flow path 30 communicates with the fuel gas supply communication hole 24a and the fuel gas discharge communication hole 24b. A cooling medium flow path 28 communicating with the cooling medium supply communication hole 22a and the cooling medium discharge communication hole 22b is formed on the surface 18b opposite to the surface 18a of the anode separator 18.

  The cathode-side separator 16 is integrally molded with a first seal member 32 on a thin metal plate, and the anode-side separator 18 is integrally molded with a second seal member 34 on a thin metal plate.

  The electrolyte membrane / electrode structure 14 includes, for example, a solid polymer electrolyte membrane 36 in which a perfluorosulfonic acid thin film is impregnated with water, and a cathode side electrode 38 and an anode side electrode 40 that sandwich the solid polymer electrolyte membrane 36. With.

  The cathode side electrode 38 and the anode side electrode 40 are formed by uniformly coating the surface of the gas diffusion layer with a gas diffusion layer made of carbon paper or the like and porous carbon particles carrying a platinum alloy on the surface. An electrode catalyst layer. The electrode catalyst layers are formed on both surfaces of the solid polymer electrolyte membrane 36.

  In one separator constituting the unit cell 12, for example, the cathode side separator 16, a plurality of positioning pin members 42 are integrally provided on the separator surface. The positioning pin member 42 may be formed of the same material as the first seal member 32, and is preferably formed of a resin member having excellent chemical resistance. Specifically, an elastically deformable resin material such as polyethylene (PE), polypropylene (PP), ABS resin, polyphenylene sulfide (PPS), or polyether ether ketone (PEEK) is used.

  The positioning pin member 42 is formed by insert molding, outsert molding, mold molding, or the like in addition to a method of integrally molding the separator side (surface 16a) of the cathode-side separator 16 by injection molding or injection press molding. Further, the positioning pin member 42 may be fixed to the separator surface of the cathode side separator 16 by welding (FMS), screw fastening or the like.

  The positioning pin member 42 includes four elastic piece portions 44 arranged concentrically. As shown in FIGS. 2 and 3, each elastic piece 44 has an inclined surface (locking portion) 44 a that is inclined outward in a direction away from the cathode-side separator 16, and the elastic piece 44. At the open end portion on the large diameter side, a folded portion 44b bent inward is provided.

  In order to insert the positioning pin member 42 into a position corresponding to each positioning pin member 42 along the separator stacking direction (arrow A direction) in another separator constituting the unit cell 12, for example, the anode side separator 18. Positioning hole 46 is provided. The opening diameter D1 of the positioning hole 46 is set to a smaller diameter (D1 <D2) than the maximum virtual diameter D2 of the positioning pin member 42 (see FIG. 3).

  In the solid polymer electrolyte membrane 36 constituting the electrolyte membrane / electrode structure 14, a hole 48 having the same diameter or a larger diameter as the positioning hole 46 is formed coaxially with the positioning hole 46.

  The operation of assembling the fuel cell 10 configured as described above will be described below.

  First, as shown in FIGS. 1 and 3, the cathode side separator 16 and the anode side separator 18 are disposed with the electrolyte membrane / electrode structure 14 interposed therebetween. Then, by pressing the cathode side separator 16 and the anode side separator 18 together, each positioning pin member 42 provided in the cathode side separator 16 is provided in each hole 48 provided in the solid polymer electrolyte membrane 36. And it inserts in each positioning hole 46 provided in the anode side separator 18.

  At that time, the opening diameter D1 of the positioning hole 46 is set to be smaller than the maximum virtual diameter D2 of the positioning pin member 42. For this reason, each elastic piece part 44 which comprises the positioning pin member 42 is pushed in in the positioning hole 46 in the state which mutually elastically deformed mutually in the radial inside direction.

  Next, when the pressing force to each elastic piece portion 44 is released, the inclined surface 44 a of each elastic piece portion 44 is locked to the inner peripheral surface of each positioning hole portion 46. Therefore, the unit cells 12 are positioned and assembled via the positioning pin members 42 and the positioning holes 46 (see FIG. 2).

  In this case, in the first embodiment, the unit cell 12 can be accurately aligned only by inserting the positioning pin member 42 provided integrally with the cathode separator 16 into the positioning hole 46 provided in the anode separator 18. Can be assembled. For this reason, the assembling work of the unit cells 12 is simplified, and particularly when the fuel cell 10 is assembled by stacking a large number of the unit cells 12, the assembling workability is improved at once.

  In addition, since the number of parts of the fuel cell 10 is greatly reduced, the manufacturing cost can be reduced favorably. Thereby, the effect that the unit cell 12 can be assembled with high accuracy and easily with a simple and economical configuration is obtained.

  The operation of the fuel cell 10 configured as described above will be described below.

  First, as shown in FIG. 1, an oxidant gas such as an oxygen-containing gas is supplied to the oxidant gas supply communication hole 20a, and a fuel gas such as a hydrogen-containing gas is supplied to the fuel gas supply communication hole 24a. Further, a coolant such as pure water, ethylene glycol, or oil is supplied to the coolant supply passage 22a.

  For this reason, the oxidant gas is introduced from the oxidant gas supply communication hole 20a into the oxidant gas flow path 26 provided in the cathode side separator 16. The oxidant gas is supplied to the cathode side electrode 38 constituting the electrolyte membrane / electrode structure 14 while moving in the direction of arrow B through the oxidant gas flow path 26.

  On the other hand, the fuel gas is introduced into the fuel gas flow path 30 provided in the anode separator 18 from the fuel gas supply communication hole 24a. The fuel gas introduced into the fuel gas flow path 30 is supplied to the anode side electrode 40 constituting the electrolyte membrane / electrode structure 14 while moving in the arrow B direction.

  Therefore, in the electrolyte membrane / electrode structure 14, the oxidant gas supplied to the cathode side electrode 38 and the fuel gas supplied to the anode side electrode 40 are consumed by an electrochemical reaction in the electrode catalyst layer, thereby generating power. Is done.

  Next, the oxidant gas consumed by being supplied to the cathode side electrode 38 is discharged to the oxidant gas discharge communication hole 20b. On the other hand, the used fuel gas consumed by being supplied to the anode side electrode 40 is discharged into the fuel gas discharge communication hole 24b.

  The cooling medium flows along the arrow B direction after being introduced into the cooling medium flow path 28 from the cooling medium supply communication hole 22a. The cooling medium cools the electrolyte membrane / electrode structure 14 and then is discharged into the cooling medium discharge communication hole 22b.

  4 is an exploded perspective view of a fuel cell 50 according to a second embodiment of the present invention, and FIG. 5 is a cross-sectional view of the fuel cell 10 taken along line VV in FIG. The same components as those of the fuel cell 10 according to the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted. Similarly, the detailed description of the third and subsequent embodiments is also omitted.

  The fuel cell 50 is configured by alternately stacking first unit cells 12a and second unit cells 12b. A plurality of positioning pin members 42a are integrally provided on the cathode-side separator 16 constituting the first unit cell 12a. A plurality of positioning holes 46a and holes 48a are formed in the anode separator 18 and the electrolyte membrane / electrode structure 14 constituting the first unit cell 12a, respectively.

  A plurality of positioning pin members 42b are integrally provided on the cathode-side separator 16 constituting the second unit cell 12b. A plurality of positioning holes 46b and holes 48b are formed in the anode separator 18 and the electrolyte membrane / electrode structure 14 constituting the second unit cell 12b, respectively.

  The positioning pin member 42a of the first unit cell 12a and the positioning pin member 42b of the second unit cell 12b are arranged so as to be shifted (offset) from each other in the stacking direction (arrow A).

  In the cathode-side separator 16 constituting the first unit cell 12a, a relief hole 52a is formed at a position corresponding to the positioning pin member 42b along the stacking direction. In the cathode-side separator 16 constituting the second unit cell 12b, a relief hole 52b is formed at a position corresponding to the positioning pin member 42a along the stacking direction.

  The first unit cell 12a and the second unit cell 12b are provided with a plurality of guide holes 54 for positioning them integrally. A guide rod (not shown) is integrally inserted into the guide hole 54 to position and hold the entire fuel cell 50.

  In the second embodiment configured as described above, the assembly work of the first unit cell 12a and the second unit cell 12b is simplified, and the assembly workability of the entire fuel cell 50 is improved at once. The same effect as that of the first embodiment can be obtained.

  Moreover, in the second embodiment, the positioning pin member 42a of the first unit cell 12a and the positioning pin member 42b of the second unit cell 12b are arranged so as to be shifted from each other in the stacking direction. Accordingly, there is an advantage that the positioning pin member 42a and the positioning pin member 42b which are stacked on each other do not interfere with each other, and the size of the entire fuel cell 50 in the stacking direction is favorably shortened.

  FIG. 6 is a partial cross-sectional explanatory view of a fuel cell 60 according to the third embodiment of the present invention.

  The fuel cell 60 is configured by stacking a plurality of power generation units (unit cells) 62 along the horizontal direction (arrow A direction). The power generation unit 62 includes a first separator 64, a first electrolyte membrane / electrode structure (electrolyte / electrode structure) 66 a, a second separator 68, a second electrolyte membrane / electrode structure 66 b, and a third separator 70.

  The first and second electrolyte membrane / electrode structures 66a, 66b include solid polymer electrolyte membranes 36a, 36b, cathode side electrodes 38a, 38b and anode side electrodes 40a sandwiching the solid polymer electrolyte membranes 36a, 36b, 40b. The anode side electrodes 40a and 40b constitute a so-called step type MEA having a smaller surface area than the cathode side electrodes 38a and 38b.

  A first oxidant gas flow path 26a is provided on the surface of the first separator 64 on the first electrolyte membrane / electrode structure 66a side. A surface of the second separator 68 on the first electrolyte membrane / electrode structure 66a side is provided with a first fuel gas flow path 30a, and a surface of the second separator 68 on the second electrolyte membrane / electrode structure 66b side. Is provided with a second oxidizing gas channel 26b. A second fuel gas flow path 30b is provided on the surface of the third separator 70 on the second electrolyte membrane / electrode structure 66b side.

  The first separator 64 is integrally provided with a plurality of positioning pin members 42 on the separator surface. The third separator 70 is provided with a positioning hole 46 for inserting the positioning pin member 42 at a position corresponding to each positioning pin member 42 along the separator stacking direction (arrow A direction). A hole 48 is formed in the second separator 68 coaxially with the positioning hole 46.

  In the third embodiment configured as described above, the power generation unit is obtained by merely inserting the positioning pin member 42 provided integrally with the first separator 64 into the positioning hole 46 provided in the third separator 70. 62 can be assembled by positioning and holding. Thereby, in 3rd Embodiment, while the assembly workability | operativity of the fuel cell 60 improves effectively, it becomes possible to reduce manufacturing cost, etc., and the same effect as said 1st Embodiment is acquired. .

  Note that the third embodiment can be configured in the same manner as the second embodiment. Further, as shown in FIG. 7, the positioning pin members 42 of the unit cells 12a and 12b adjacent to each other may be configured to face each other and be offset from each other. The same applies to the fourth and subsequent embodiments described below.

  FIG. 8 is a partial cross-sectional explanatory view of a fuel cell 80 according to the fourth embodiment of the present invention.

  In the unit cell 82 constituting the fuel cell 80, a plurality of positioning pin members 84 are integrally provided on the separator surface of the cathode separator 16. As shown in FIG. 9, the positioning pin member 84 includes two elastic legs 86 arranged concentrically. A claw-shaped locking portion 88 that bulges outward in the radial direction is integrally provided at the tip of each leg portion 86. The distal end surface of the locking portion 88 constitutes a spherical guide surface 88a that is inclined outward from the center side.

  The anode separator 18 is provided with a positioning hole 46 having a diameter smaller than that of the claw-shaped locking portion 88, and a hole 48 is formed in the electrolyte membrane / electrode structure 14.

  In the fourth embodiment configured as described above, the cathode-side separator 16 and the anode-side separator 18 are provided on the front end surface of the locking portion 88 when they are overlapped with the electrolyte membrane / electrode structure 14 interposed therebetween. The engaging portions 88 are elastically deformed inward from each other under the guiding action of the spherical guide surface 88a. And each latching | locking part 88 spreads mutually outward after penetrating the positioning hole part 46 (refer FIG. 8).

  Accordingly, since the locking portion 88 is locked to the inner peripheral surface of the positioning hole portion 46, the unit cell 82 is positioned and held and assembled through the positioning pin members 84 and the positioning hole portions 46. Thereby, the fourth embodiment can obtain the same effects as those of the first to third embodiments.

  FIG. 10 is a partial cross-sectional explanatory view of a fuel cell 90 according to the fifth embodiment of the present invention.

  In the unit cell 92 constituting the fuel cell 90, a plurality of positioning pin members (groups) 94 are integrally provided on the separator surface of the cathode separator 16. As shown in FIG. 11, the positioning pin member 94 includes four elastic struts 96 arranged concentrically. A locking sphere (locking part) 98 is integrally formed at the tip of each strut 96. Provided.

  The anode side separator 18 is provided with a positioning hole 46 having a diameter smaller than the virtual circle diameter formed through the four locking spheres 98, and the electrolyte membrane / electrode structure 14 has a hole 48. It is formed.

  In the fifth embodiment configured as described above, when the cathode side separator 16 and the anode side separator 18 are overlapped with each other with the electrolyte membrane / electrode structure 14 interposed therebetween, the locking sphere 98 is positioned in the positioning hole 46. It abuts on the inner peripheral surface of. For this reason, after each support | pillar part 96 is elastically deformed mutually inward and penetrates the positioning hole part 46, it mutually expands outward (refer FIG. 10).

  Accordingly, since the locking sphere 98 is locked to the inner peripheral surface of the positioning hole 46, the unit cell 92 is positioned and assembled via the positioning pin members 94 and the positioning holes 46. Thereby, the fifth embodiment can obtain the same effects as those of the first to fourth embodiments.

1 is an exploded perspective view of a fuel cell according to a first embodiment of the present invention. It is the II-II sectional view taken on the line of the said fuel cell in FIG. It is a perspective explanatory view of the positioning pin member which constitutes the fuel cell. FIG. 6 is an exploded perspective view of a fuel cell according to a second embodiment of the present invention. FIG. 5 is a cross-sectional view of the fuel cell taken along line VV in FIG. 4. It is a partial cross section explanatory view of the fuel cell concerning a 3rd embodiment of the present invention. It is explanatory drawing of the structure which each positioning pin member of the adjacent electric power generation unit faced mutually and was mutually offset. It is a partial cross section explanatory view of the fuel cell concerning a 4th embodiment of the present invention. It is a perspective explanatory view of the positioning pin member which constitutes the fuel cell. It is a partial cross section explanatory view of the fuel cell concerning a 5th embodiment of the present invention. It is a perspective explanatory view of the positioning pin member which constitutes the fuel cell. 1 is an explanatory diagram of a solid polymer electrolyte fuel cell disclosed in Patent Document 1. FIG.

Explanation of symbols

10, 50, 60, 80, 90 ... Fuel cells 12, 12a, 12b, 82, 92 ... Unit cells 14, 66a, 66b ... Electrolyte membrane / electrode structures 16, 18, 64, 70 ... Separator 26 ... Oxidant gas Flow path 28 ... Cooling medium flow path 30 ... Fuel gas flow path 32, 34 ... Seal member 36 ... Solid polymer electrolyte membrane 38 ... Cathode side electrode 40 ... Anode side electrodes 42, 42a, 84, 94 ... Positioning pin member 44 ... Elastic piece 44a ... Inclined surface 46, 46a, 46b ... Positioning hole 48, 48a, 48b ... Hole 62 ... Power generation unit 86 ... Leg 88 ... Locking portion 88a ... Spherical guide surface 96 ... Strut 98 ... Stop ball part

Claims (5)

A fuel cell comprising a unit cell for sandwiching an electrolyte / electrode structure provided with a pair of electrodes on both sides of an electrolyte with a separator,
In one of the separators constituting the unit cell, a positioning pin member is integrally provided on the separator surface, and
The other separator constituting the unit cell is provided with a positioning hole portion for inserting the positioning pin member at a position corresponding to the positioning pin member along the separator stacking direction. battery.   2. The fuel cell according to claim 1, wherein the positioning pin member has a locking portion that penetrates the positioning hole and is locked to the other separator. The fuel cell according to claim 1 or 2, wherein a plurality of the unit cells are stacked,
In the unit cells adjacent to each other, the positioning pin member provided in one of the unit cells and the positioning pin member provided in the other unit cell are arranged so as to be displaced from each other in the stacking direction. A fuel cell. 4. The fuel cell according to claim 3, wherein one of the unit cells has a relief hole formed at a position corresponding to the positioning pin member provided in the other unit cell along the stacking direction. ,
In the other unit cell, a escape hole is formed at a position corresponding to the positioning pin member provided in one unit cell along the stacking direction.   5. The fuel cell according to claim 1, wherein the positioning pin member is formed of an elastically deformable resin material. 6.

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