JP6123635B2 - Fuel cells and fuel cells - Google Patents

Description

  The present invention relates to a fuel cell and a fuel cell.

  The fuel cell has a stack structure in which a plurality of fuel cells serving as power generation units are stacked, and each fuel cell sandwiches a membrane electrode assembly between both anode-side and cathode-side separators facing each other. In this way, when sandwiching the membrane electrode assembly between both separators, a method has been proposed for ensuring sealing performance on the outer peripheral side of the membrane electrode assembly (for example, Patent Document 1).

JP 2013-149438 A

  According to the sealing method proposed in this patent document, an elastic sealing material made of rubber is disposed between the separators sandwiching the membrane electrode assembly, and this is adhered to the separator, whereby the sealing property between the separators Is demonstrating. By the way, the fuel cell is mounted on, for example, a vehicle or the like in a stack structure in which a plurality of fuel cells are stacked and fastened in the stacking direction. In such a stack structure, both the anode-side and cathode-side separators sandwiching the sealing material are in contact with one of the separators of adjacent fuel cells via a gasket for sealing between the cells. Since the contact state of such a separator is normally maintained by the fastening force in the state of the stack structure, there is no particular problem. However, it has been pointed out that the following new problems may arise.

  Each fuel cell sandwiches a membrane electrode assembly in the central region between both anode-side and cathode-side separators. In addition, the fuel battery cell includes a sealing material adhered between the separators on the periphery of the membrane electrode assembly. Therefore, a plurality of fuel cells are stacked in the central region of the separator and the outer peripheral region of the separator, and a plurality of the fuel cells are stacked to form a stack structure fuel cell. Since the material of the sealing material is rubber, the sealing material can be damaged due to aging and volume shrinkage under a low temperature environment. As a result, both the anode-side and cathode-side separators in a certain fuel battery cell are attracted in the outer peripheral area of the separator by the seal material that has been drastically or contracted in volume due to the adhesion to the sealing material, and the thickness of the separator outer peripheral area is increased. Can be thin. If it becomes like this, the clearance gap between the separators in an adjacent fuel battery cell will expand, and there exists a concern about the fall of the sealing performance by the gasket which aims at the sealing between cells. Such expansion of the gap between the separators can occur in each of the stacked fuel cells. In addition, in the case where some fuel cells are blocked by sticking a separator between adjacent cells, the fuel cell at the end of the block and the fuel cell at the next block In between, the expansion of the gap between the separators can be significant. In the above-mentioned patent document, since the situation that the thickness of the outer peripheral region of the separator can be reduced with the settling or volume shrinkage of the sealing material is not assumed at all, the sealing performance between the stacked fuel cells is maintained. Has been requested. In addition, it is also required to reduce the manufacturing cost of a fuel cell having a stack structure in which fuel cells are stacked.

  In order to achieve at least a part of the problems described above, the present invention can be implemented as the following forms.

  (1) According to one aspect of the present invention, a fuel battery cell is provided. The fuel cell is a fuel cell in which a membrane electrode assembly is sandwiched between a first separator and a second separator, and the first and second separators are connected to a power generation region of the membrane electrode assembly. Each of the outer edge portions extending from the opposing separator central region to the peripheral outer edge is opposed to the outer edge portion with an elastic sealing material that performs a sealing function on the outer peripheral edge side of the membrane electrode assembly interposed therebetween. The thickness of the outer edge from the first separator to the second separator at the outer edge facing each other is such that the first electrode sandwiching the membrane electrode assembly in the central region of the separator The thickness from the separator to the second separator is larger.

  A plurality of fuel cells of the above form are stacked to constitute a fuel cell having a stack structure. In the fuel cell having the stack structure, the first separator of one fuel battery cell of the adjacent fuel battery cells is fastened so as to come into contact with the second separator of the other fuel battery cell. The fastening force that brings about such fastening is naturally applied to the outer edge of the fuel cell of the above-described form, and the outer edge of one fuel cell of the adjacent fuel cell contacts the outer edge of the other fuel cell. Then, the elastic sealing material at the outer edge of each fuel cell is compressed. In the fuel cell of the above aspect, the thickness of the outer edge portions of the first and second separators facing each other with the elastic sealing material interposed therebetween is changed from the first separator holding the membrane electrode assembly to the second in the separator central region. Since the thickness is larger than the thickness applied to the separator, the load based on the fastening force that brings about the cell fastening is increased at the outer edge portion through which the elastic sealing material is interposed. As a result, according to the fuel cell of the above embodiment, even if the elastic sealing material is drooped or contracted in volume, the load applied to the outer edge portion through which the elastic sealing material is interposed is large. The expansion of the gap between the separators in adjacent fuel cells can be suppressed, and the sealing performance between the cells can be maintained. In the fuel cell of the above embodiment, the thickness of the outer edge portion may be increased, and the thickness of the outer edge portion can be easily increased by adjusting the shape of the separator. Therefore, according to the fuel cell of the above embodiment, it is possible to reduce the cell manufacturing cost, and hence the manufacturing cost as a fuel cell, and to seal between adjacent fuel cells by a simple measure of separator shape adjustment. Performance can be maintained.

  (2) In the fuel cell of the above aspect, the thickness of the outer edge portion is set to be larger than the thickness of the outer edge portion of the fuel cell included in the stack structure in which the plurality of fuel cells are stacked. May be. By doing so, the load based on the fastening force is increased by an amount corresponding to the difference from the thickness of the outer edge portion in the stack structure, and the sealing performance between the cells can be maintained as described above.

  (3) In the fuel battery cell according to the above aspect, the first and second separators are formed of metal steel plates, and the outer edges of the first and second separators are opposed to each other. It is possible to have a convex portion protruding toward the surface, and to define the thickness of the outer edge portion at the convex portion. In this way, the convex part of the outer edge part functions as a spring when the adhesive seal is compressed by receiving a fastening load because the separator itself formed from the metal steel plate protrudes outward from the cell. To do. Therefore, according to the fuel cell of this embodiment, since the elastic function of the elastic sealing material can be resisted by the spring function of the convex portion, it can contribute to the maintenance of the sealing performance between the cells.

  (4) In the fuel cell of the above aspect, each of the first and second separators includes a connector mounting portion to which a cell monitor connector is mounted on the outer edge portion. You may make it oppose through the interposition of an elastic sealing material. In this way, the thickness of the connector mounting portion with the elastic seal material interposed can be made larger than the thickness described above in the central region of the separator. The expansion of the gap between the connector mounting portions in the adjacent fuel battery cells in the battery can be suppressed. As a result, the cell monitor connector can be mounted on the connector mounting portion without any trouble, and the connector can be prevented from dropping or being damaged or broken.

  (5) According to another aspect of the present invention, a fuel cell is provided. The fuel cell is a fuel cell in which a plurality of fuel cells each having a membrane electrode assembly sandwiched between a first separator and a second separator are stacked, and each of the fuel cells includes the first and second fuel cells. The separator is a separator having an outer edge extending from the separator central region facing the power generation region of the membrane electrode assembly to a peripheral outer edge, and the outer edge is an elastic material that performs a sealing function on the outer peripheral edge of the membrane electrode assembly. It is made to oppose with a sealing material interposed. Then, the second separator of the other fuel battery cell comes into contact with and is pressed against the first separator of one fuel battery cell of the adjacent fuel battery cells, and the load applied to the outer edge portion is applied to the separator. It is fastened so as to be larger than the load applied to the central region.

  In the fuel cell of the above aspect, the load based on the fastening force that brings about the cell fastening is made larger than the central region of the separator at the outer edge portion with the elastic sealing material interposed. As a result, according to the fuel cell of the above aspect, even if the elastic sealing material is drooped or contracted in volume, the load applied to the outer edge portion where the elastic sealing material is interposed is large. The expansion of the gap between the separators can be suppressed, and the sealing performance between the cells can be maintained.

  (6) In the fuel cell of the above aspect, each of the fuel battery cells may be the fuel battery cell of each of the above aspects. In this way, each of the stacked fuel cells itself defines the thickness of the outer edge portion with the elastic sealing material interposed therebetween as described above, so that the load based on the fastening force that brings about the cell fastening causes the elastic sealing material to In the outer edge part interposed, it is made larger than the central region of the separator. Therefore, according to the fuel cell of this embodiment, it is only necessary to replace the existing battery cell, so that the fuel cell manufacturing cost can be reduced in addition to maintaining the sealing performance between the cells.

  In addition, this invention can be implement | achieved with various forms, for example, can be implement | achieved with the form as a manufacturing method of a fuel cell, or a manufacturing method of a fuel cell.

It is a schematic perspective view which shows the structure of the fuel cell 10 as embodiment of this invention. FIG. 2 is a schematic perspective view showing an exploded configuration of a unit cell 100. 3 is a schematic plan view showing a configuration of an anode separator 120. FIG. FIG. 4 is a schematic cross-section of the fuel cell 10 taken along line 4-4 at an enlarged portion of C part in FIG. 3. It is explanatory drawing which shows typically the dimensional relationship of each structural member in a unit cell independent. It is explanatory drawing which shows the mode of manufacture of the unit cell 100 typically. It is explanatory drawing which shows a mode that the unit cell 100 is laminated | stacked and fastened. It is a schematic perspective view which shows roughly the mode of the separator corner part D shown in FIG. It is explanatory drawing which shows typically the mode of the convex part 123t accompanying compression of the adhesive seal | sticker 140. FIG. It is explanatory drawing which shows typically the dimensional relationship of each structural member in the cell single of unit cell 100A of other embodiment. 5 is a schematic cross-sectional view of a fuel cell 10A of another embodiment corresponding to FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic perspective view showing the configuration of a fuel cell 10 as an embodiment of the present invention. The fuel cell 10 has a stack structure in which a plurality of unit cells 100 as fuel cells are stacked in the Z direction (hereinafter also referred to as “stacking direction”) and sandwiched between a pair of end plates 170F and 170E. The fuel cell 10 is fastened in the cell stacking direction by a fastening bolt 20 at the lower center of the cell and a fastening bolt (not shown) at the cell corner. The fuel cell 10 has a front end side terminal plate 160F between a front end side end plate 170F and the unit cell 100 with a front end side insulating plate 165F interposed therebetween. Similarly, the fuel cell 10 has a rear end side terminal plate 160E between the rear end side end plate 170E and the unit cell 100 with a rear end side insulating plate 165E interposed therebetween. The unit cell 100, the terminal plates 160F and 160E, the insulating plates 165F and 165E, and the end plates 170F and 170E each have a plate structure having a substantially rectangular outer shape, and the long sides are in the X direction (horizontal direction). ) And the short sides are arranged along the Y direction (vertical direction, vertical direction).

  The end plate 170F, the insulating plate 165F, and the terminal plate 160F on the front end side include a fuel gas supply hole 172IN and a fuel gas discharge hole 172OT, a plurality of oxidant gas supply holes 174IN and an oxidant gas discharge hole 174OT, and a plurality of cooling waters. It has a supply hole 176IN and a cooling water discharge hole 176OT. These supply / discharge holes are connected to respective holes (not shown) provided at corresponding positions of the unit cells 100 to constitute gas / cooling water supply / discharge manifolds corresponding to the respective holes. On the other hand, these supply / discharge holes are not provided in the end plate 170E, the insulating plate 165E, and the terminal plate 160E on the rear end side. This is because the reaction gas (fuel gas, oxidant gas) and cooling water are supplied from the front end plate 170F to each unit cell 100 via the supply manifold, while the exhaust gas from each unit cell 100 is discharged. In addition, the fuel cell is a type that discharges discharged water from the front end side end plate 170F to the outside through a discharge manifold. However, the present invention is not limited to this, for example, a type in which reaction gas and cooling water are supplied from the end plate 170F on the front end side, and exhaust gas and discharge water are discharged to the outside from the end plate 170E on the rear end side. Can be of various types.

  The plurality of oxidant gas supply holes 174IN are arranged along the X direction (long side direction) at the outer edge of the lower end of the front end side end plate 170F, and the plurality of oxidant gas discharge holes 174OT are arranged at the outer edge of the upper end. It is arrange | positioned along the X direction in the part. The fuel gas supply hole 172IN is disposed at the upper end in the Y direction (short side direction) of the outer edge at the right end of the front end plate 170F, and the fuel gas discharge hole 172OT is disposed in the Y direction at the outer edge at the left end. It is arranged at the lower end. The plurality of cooling water supply holes 176IN are arranged along the Y direction below the oxidant gas supply holes 174IN, and the plurality of cooling water discharge holes 176OT are arranged above the oxidant gas discharge holes 174OT in the Y direction. Are arranged along.

  The terminal plate 160F on the front end side and the terminal plate 160E on the rear end side are current collecting plates for the generated power of each unit cell 100, and output the power collected from terminals not shown to the outside.

  FIG. 2 is a schematic perspective view showing the structure of the unit cell 100 in an exploded manner. As shown in the figure, a unit cell 100 includes a membrane electrode gas diffusion layer assembly (MEGA) 110, an anode-side separator 120 disposed so as to sandwich both surfaces of the MEGA 110, and a cathode-side separator. 130, an adhesive seal 140, and a gas flow path member 150.

  The MEGA 110 includes a membrane electrode assembly (MEA) in which a pair of catalyst electrode layers are formed on both surfaces of an electrolyte membrane, and this MEA is a gas diffusion layer (Gas Diffusion Layer / GDL) that allows gas diffusion and permeation of the MEA. It is a power generator configured to be sandwiched. Note that MEGA may be referred to as MEA.

  The anode-side separator 120 and the cathode-side separator 130 are composed of members having gas barrier properties and electronic conductivity, for example, carbon members such as dense carbon that compresses carbon particles and makes gas impermeate, It is made of a press-molded metal member such as stainless steel or titanium steel. In this embodiment, the anode-side separator 120 was produced by press molding stainless steel.

  The anode separator 120 includes a plurality of grooved fuel gas flow paths on the MEGA 110 side surface, and a plurality of grooved cooling water flow paths on the opposite surface. They are arranged alternately on the front and back of the separator. These flow paths will be described later. The anode-side separator 120 includes a fuel gas supply hole 122IN and a fuel gas discharge hole 122OT, a plurality of oxidant gas supply holes 124IN and an oxidant gas discharge hole 124OT, and a plurality of supply and discharge holes constituting the manifold described above. A cooling water supply hole 126IN and a cooling water discharge hole 126OT are provided. Similarly, the cathode separator 130 includes a fuel gas supply hole 132IN and a fuel gas discharge hole 132OT, a plurality of oxidant gas supply holes 134IN and an oxidant gas discharge hole 134OT, a plurality of cooling water supply holes 136IN and a cooling water discharge. Hole 136OT. Similarly, in the adhesive seal 140, the fuel gas supply hole 142IN and the fuel gas discharge hole 142OT, and the plurality of oxidant gas supply holes 144IN and the oxidant corresponding to the supply / discharge holes of the anode separator 120 are provided. A gas discharge hole 144OT, a plurality of cooling water supply holes 146IN, and a cooling water discharge hole 146OT are provided.

  The adhesive seal 140 is formed of rubber having sealing properties, insulating properties, and elasticity, such as ethylene / propylene / diene rubber (EPDM), nitrile rubber (NBR), fluorine rubber (FKM), and the like. A power generation window 141 adapted to a rectangular shape is included. The peripheral edge of the power generation area window 141 has a stepped shape, and the MEGA 110 is assembled and attached to the stepped portion. The MEGA 110 thus mounted on the power generation region window 141 overlaps the adhesive seal 140 at the step portion of the adhesive seal 140, and the region exposed at the power generation region window 141 is supplied with fuel gas from the anode separator 120 described later. Region 112 is assumed. The adhesive seal 140 includes the supply / discharge holes described above in the peripheral region of the power generation region window 141 in which the MEGA 110 is incorporated, and the anode-side separator 120 and the cathode-side separator 130 are connected in a state where the MEGA 110 is incorporated in the power generation region window 141. , Seal around each supply and discharge hole. That is, the adhesive seal 140 seals the MEGA 110 at the step portion over the outer region of the power generation region 112, and is interposed between the anode-side separator 120 and the cathode-side separator 130 in the rectangular outer peripheral region of the MEGA 110. And seal. Thus, the adhesive seal 140 that seals both the anode and cathode separators functions as an elastic seal material in the present application, and therefore is also referred to as an elastic seal material 140 as appropriate. In FIG. 2, the adhesive seal 140 is shown as having a rectangular shape alone. However, after the above-described rubber materials are disposed between both separators, the adhesive seal 140 is subjected to heat melting and cooling curing in FIG. 2. Shaped as shown. The manner in which the adhesive seal 140 is formed will be described later. Both the anode-side separator and the separator-side separator are described later in order to ensure the sealing performance of the supply / discharge holes for each of the fuel gas, oxidant gas, and cooling water when the unit cells 100 are stacked. As shown in FIG. 3, a fuel gas sealing material 300, an oxidant sealing material 301, and a cooling water sealing material 302 are provided.

  The gas flow path member 150 is located between the MEGA 110 and the cathode-side separator 130 with the adhesive seal 140 interposed therebetween, and the oxidant gas applied from the oxidant gas supply hole 134IN to the oxidant gas discharge hole 134OT. The flow path is formed. The gas flow path member 150 has its upper and lower ends extending so as to overlap the upper end of the oxidant gas supply hole 134IN and the lower end of the oxidant gas discharge hole 134OT. For this reason, the gas flow path member 150 introduces the oxidant gas supplied from the oxidant gas supply hole 134IN of the cathode separator 130 from the lower end of the member, and introduces the introduced oxidant gas into the surface direction (XY) of the MEGA 110. Flow along the plane direction). Then, the gas flow path member 150 discharges excess oxidant gas from the upper end of the member to the oxidant gas discharge hole 134OT of the cathode separator 130. As such a gas flow path member 150, a porous material having gas diffusibility and conductivity such as a metal porous body (for example, expanded metal) is used. Further, the gas flow path member 150 includes gas-impermeable thin leaf-like sealing sheets 151 at the upper and lower ends in FIG. 2, and the sheets are joined to the upper and lower end regions of the MEGA 110.

  FIG. 3 is a schematic plan view showing the configuration of the anode separator 120. FIG. 3 shows a state as viewed from the surface facing the other unit cell 100 adjacent to the anode separator 120 (hereinafter also referred to as “cooling surface”). A surface facing the MEGA 110 opposite to the cooling surface is also referred to as a “gas surface”. The anode-side separator 120 is formed by press-molding stainless steel or the like, and sandwiches the MEGA 110 together with the cathode-side separator 130 with an adhesive seal 140 and a gas flow path member 150 interposed therebetween as shown in FIG. The anode-side separator 120 includes a separator central region 121 facing the power generation region 112 of the MEGA 110 described above, and a plurality of first and second grooves 202 and 204 described later are alternately arranged. A fuel gas supply hole 122IN, a fuel gas discharge hole 122OT, and a plurality of oxidant gas supply holes 124IN An oxidant gas discharge hole 124OT, a plurality of cooling water supply holes 126IN and a cooling water discharge hole 126OT are provided. Of these supply and discharge holes, the fuel gas supply hole 122IN and the fuel gas discharge hole 122OT are individually sealed by the fuel gas sealing material 300, and have a plurality of oxidant gas supply holes 124IN and a plurality of oxidant gas discharge holes 124OT. Is sealed for each row of holes by the oxidant sealing material 301. The cooling water sealing material 302 surrounds the cooling water circulation area including the plurality of cooling water supply holes 126IN, the cooling water discharge holes 126OT, and the separator central area 121 on the cooling surface side, and seals the cooling water circulation area. . Such a supply / discharge hole seal is also made in the cathode separator 130.

  The first groove 202 is a concave groove that is concave on the gas surface side of the anode-side separator 120 as described above, and in FIG. 3 on the back surface side of the paper surface, and extends in this gas surface. The second groove 204 is a concave groove on the cooling surface side of the anode-side separator 120 described above, which is a concave groove on the front surface side in FIG. 3, and extends on this cooling surface. Then, the first groove 202 and the second groove 204 are formed as a plurality of streaky ridges by press molding in which a concavo-convex mold adapted to both groove shapes is pressed against the separator central region 121, and the separator central region 121. Are alternately arranged on the front and back surfaces of the anode-side separator 120. That is, the anode-side separator 120 has a cross-sectional uneven shape (cross-sectional corrugated shape) in which the first grooves 202 and the second grooves 204 are alternately and repeatedly arranged in a longitudinal sectional view in FIG.

  The first groove 202 that is concave on the gas surface side is a fuel gas passage groove that supplies fuel gas to the MEGA 110 exposed to the power generation area window 141 of the adhesive seal 140 (hereinafter also referred to as “fuel gas passage groove 202”). The second groove 204 that is configured and concave on the cooling surface side constitutes a rib that partitions the fuel gas flow channel groove 202, and the cooling water passes through when the anode separator 120 comes into contact with the cathode separator 130 described later. The cooling water channel groove (hereinafter also referred to as “cooling water channel groove 204”) is configured. Then, the fuel gas flow path 200 constituted by the plurality of fuel gas flow path grooves 202 is formed in a serpentine shape from the fuel gas supply hole 122IN to the fuel gas discharge hole 122OT, and the gas surface described above on the back side of the paper in FIG. Formed on the side. The unit cell 100 of the present embodiment includes a serpentine-shaped fuel gas flow channel 200 in which a fuel gas flow channel groove 202 positioned on the upper and lower ends of the separator central region 121 shown in FIG. The region 121 extends in the left-right direction, that is, the x direction in FIG. In this way, when the separator central region 121 faces the power generation region 112 of the MEGA 110, the fuel gas flow path extending in the left-right direction of the separator central region 121 on the outer edge 123 side also on the periphery of the power generation region 112 Fuel gas can be supplied from the groove 202. 3, the first groove 202 that is positioned on the upper and lower ends of the separator central region 121 and extends in the left-right direction of the separator central region 121 on the outer edge portion 123 side is provided in the separator central region. In order to distinguish from the 1st groove | channel 202 located inside 121, it shall call the edge part 1st groove | channel 202t.

  Since the fuel gas channel groove 202 takes a serpentine-like groove path, the direction of the groove path is changed from the X direction to the Y direction in the conversion area A which is the left and right horizontal end area of the separator central area 121 shown in FIG. Change or vice versa. The fuel gas channel groove 202 functions as a rib that partitions the cooling water channel groove 204 on the cooling surface side in the linear channel region extending in the X direction including the conversion region A. Although the fuel gas channel groove 202 functions as a rib that partitions the coolant channel groove 204 in the linear channel region extending in the X direction, the flow of the coolant in the second groove 204 toward the coolant discharge hole 126OT side. Does not disturb. However, in the conversion region A in which the groove path direction changes, the fuel gas flow channel groove 202 serves as a wall, and the flow of the cooling water from the cooling water supply hole 126IN to the cooling water discharge hole 126OT can be hindered. In view of this, the fuel gas passage groove 202 in this region has dotted portions where the groove depth is shallow along the groove path, whereby the coolant flow between the adjacent second grooves 204 can be increased. Allow. Accordingly, the flow of the cooling water is not hindered in the conversion area A, and the cooling water flows from the cooling water supply hole 126IN toward the cooling water discharge hole 126OT. In addition, since such a groove | channel structure is not directly related to the summary of this invention, the description is abbreviate | omitted.

  In addition, the anode-side separator 120 has a cutting portion 120c and a connector mounting portion 125 at the outer edge portion 123 in the separator corner portion D on the fuel gas discharge hole 122OT side. As will be described later, the anode-side separator 120 is overlapped with the cathode-side separator 130 with an adhesive seal 140 interposed therebetween, so that the cathode-side separator 130 is exposed at a portion of the cutting portion 120c of the anode-side separator 120, The exposed portion is a cell monitor connector potential measurement unit 130Ct (not shown). The positional relationship between these parts will be described later. The connector mounting portion 125 performs a function of preventing the cell monitor connector when the cell monitor connector is mounted together with the connector mounting portion 135 of the cathode separator 130. The cell monitor connector stopped by the connector mounting portion 125 is a potential measuring unit. 130 Ct is sandwiched between measurement terminals and a measurement potential is output. The cell monitor connector is attached to the connector attachment portion 125 after the assembly of the fuel cell 10 is completed with the predetermined number of unit cells 100 as attachment / measurement units, not for each unit cell 100.

  As shown in FIG. 2, the cathode separator 130 has a substantially flat plate shape, and the upper and lower ends of the separator central region 137 facing the power generation region 112 of the MEGA 110, that is, in the vicinity of the upper and lower ends of the gas flow path member 150. The leg 131 is protruded to the back side of the paper surface in FIG. When the unit cells 100 are stacked, the legs 131 come into contact with an outer edge portion 123 (described later) in the anode-side separator 120 of the adjacent unit cell 100. This situation will be described later. Further, the cathode-side separator 130 extends from the guide convex portion 127 to the outer edge portion 138 surrounding the central region, and serves as a fuel gas supply hole 132IN and a fuel gas discharge port as the above-described reaction gas and cooling water supply / discharge holes. It has a hole 132OT, a plurality of oxidant gas supply holes 134IN and oxidant gas discharge holes 134OT, and a plurality of cooling water supply holes 136IN and cooling water discharge holes 136OT.

  Next, how the unit cells 100 are stacked in the fuel cell 10 will be described. FIG. 4 is a schematic cross-sectional view of the fuel cell 10 taken along the line 4-4 at the enlarged portion C of FIG. As illustrated, the fuel cell 10 is configured by stacking a plurality of unit cells 100, and the unit cell 100 sandwiches the MEGA 110 between an anode-side separator 120 and a cathode-side separator 130. In FIG. 4, the MEGA 110 is shown in a form in which an MEA 110D having a catalyst electrode layer bonded to both membrane surfaces of the electrolyte membrane is sandwiched between the anode-side gas diffusion layer 110A and the cathode-side gas diffusion layer 110C. Each unit cell 100 includes an outer edge portion 123 (see FIGS. 2 to 3) provided by the anode separator 120 extending outside the separator central region 121, and a power generation region 112 (see FIGS. 2 to 3) of the MEGA 110. Are joined to the MEGA 110 at the periphery. Further, each unit cell 100 is brought into contact with the separator central region 121 in which the first groove 202 and the second groove 204 are formed facing the power generation region 112 of the MEGA 110. As a result, the end first groove 202t and the first groove 202 in another part function as the fuel gas flow channel 202 extending as described above, with the concave groove opening end closed by the MEGA 110. In the cathode-side separator 130, the separator central region 137 (see FIG. 2) is opposed to the power generation region 112 of the MEGA 110 with the gas flow path member 150 interposed.

  In addition, each unit cell 100 has the outer edge portion 123 of the anode side separator 120 and the outer edge portion 138 of the cathode side separator 130 facing each other with an adhesive seal 140 that performs a sealing function on the outer peripheral edge side of the MEGA 110 interposed therebetween. ing. As shown in FIG. 4, the outer edge portion 123 of the anode side separator 120 includes a convex portion 123t that protrudes toward the outside of the cell on the oxidant gas discharge hole 124OT side. The space between the outer edge portion 138 and the outer edge portion 123 and the convex portion 123t is filled without a gap and sealed. The manner in which the adhesive seal 140 is formed will be described later.

  In the unit cells 100 stacked adjacent to each other, the bottom wall 202 s of the first groove 202 included in the anode-side separator 120 of one unit cell 100 is brought into contact with the cathode-side separator 130 of the other unit cell 100. As a result, the second groove 204 functions as the cooling water channel groove 204 that extends as described above, with the concave groove opening end closed. In the unit cells 100 stacked adjacent to each other, the legs 131 included in the cathode separator 130 of one unit cell 100 are brought into contact with the outer edge 123 of the anode separator 120 of the other unit cell 100. Accordingly, the legs 131 function as supports for the unit cells 100 at the outer edge portion 123 of the anode separator 120. In the unit cells 100 stacked adjacent to each other, the convex portion 123t of the anode side separator 120 of one unit cell 100 on the outer edge portion 123 is brought into contact with the outer edge portion 138 of the cathode side separator 130 of the other unit cell 100. As a result, the recess between the protrusions 123t is the oxidant seal on the outside of the cell from the oxidant gas discharge hole where the oxidant gas discharge hole 124OT, the oxidant gas discharge hole 134OT, and the oxidant gas discharge hole 144OT are connected. This is where the material 301 is disposed. In the following description, the oxidant gas discharge hole connected to each gas discharge hole is simply referred to as an oxidant gas discharge hole 124OT. The same applies to the supply and discharge holes for fuel gas and cooling water.

  In addition, the unit cells 100 stacked adjacent to each other have a coolant flow including a separator central region 121 and a fuel gas discharge hole 122OT on the cooling surface side where the fuel gas supply hole 122IN and the coolant flow channel 204 are opened. The cooling water sealing material 302 (see FIG. 3) surrounding the area and the oxidant sealing material 301 surrounding the oxidant gas discharge hole 124OT are connected to the anode side separator 120 of one unit cell 100 and the other at the upper end side of the separator. The unit cell 100 is sandwiched between the cathode side separator 130. The cooling water sealing material 302 and the oxidizing gas sealing material 301 surrounding the oxidizing gas supply hole 124IN are provided at the lower end of the separator, and the cooling water sealing material 302 and the fuel gas supply hole 122IN are provided at the left and right ends of the separator. The fuel gas sealing material 300 surrounding the fuel gas and the fuel gas sealing material 300 surrounding the fuel gas discharge hole 122OT are sandwiched between the anode separator 120 of one unit cell 100 and the cathode separator 130 of the other unit cell 100. The

  Thus, the fuel cell 10 in which the unit cells 100 are stacked is fastened in the cell stacking direction by a plurality of fastening bolts including a fastening bolt 20 (see FIG. 1). The fuel cell 10 having such a fastened stack structure is fastened so that the anode-side separator 120 of one unit cell 100 of the adjacent unit cells 100 contacts the cathode-side separator 130 of the other unit cell 100. Since the fastening force by the fastening bolts 20 and the like naturally extends to the outer edge portions of the stacked unit cells 100, the fuel cell 10 having the stack structure has the outer edge portion 123 of one unit cell 100 of the adjacent unit cells 100. In contact with the outer edge portion 138 of the other unit cell 100, more specifically, the leg 131 included in the outer edge portion 138, and the convex portion 123t included in the outer edge portion 123 of one unit cell 100 of the adjacent unit cell 100 is in contact with the other unit cell 100. After contacting the outer edge 138 of the unit cell 100, the adhesive seal 140 in each unit cell 100 is compressed.

  FIG. 5 is an explanatory view schematically showing the dimensional relationship of each component member in the unit cell alone, FIG. 6 is an explanatory view schematically showing the manufacturing state of the unit cell 100, and FIG. It is explanatory drawing which shows a mode that it fastens. As shown in FIG. 5, in the unit cell 100, in the state of the cell alone, the adhesive seal 140 is attached to the convex portion 123 t of the outer edge portion 123 of the anode side separator 120 and the outer edge portion 138 of the cathode side separator 130 as described above. It is opposed to intervene. In addition, the unit cell 100 has an anode-side separator that sandwiches the MEGA 110 in the separator central regions 121 and 137 with the thickness Ht of the outer edge portion between the convex portion 123t and the outer edge portion 138 facing each other with the adhesive seal 140 interposed therebetween. The cell thickness Hs from 120 to the cathode-side separator 130 is larger. In the unit cell 100 of the present embodiment, the difference ΔH between the outer edge thickness Ht and the cell thickness Hs is set to 0.1 to 0.2 mm. The difference ΔH may be determined in consideration of the compression allowance of the adhesive seal 140 accompanying the unit cell fastening, the cell thickness Hs of the unit cell 100, and the like, and is not limited to the above numerical values.

  In obtaining the unit cell 100 shown in FIG. 5, as shown in FIG. 6, in the anode separator 120, the protrusion height Hta of the convex portion 123 t is set to the groove from the opening of the first groove 202 to the bottom wall 202 s. The difference H is made larger than the depth Hsa. Then, the anode side separator 120 is superposed on the cathode side separator 130 on which the MEGA 110 and the gas flow path member 150 are laminated, and the rubber material 140m is interposed at the position where the adhesive seal 140 is formed. Next, the bottom wall of the second groove 204 is brought into contact with the MEGA 110 while pressing the anode side separator 120 toward the cathode side separator 130 with a predetermined pressure while maintaining the above difference ΔH in the anode side separator 120. In this state, the rubber material 140m is heated and melted, and the rubber material 140m surrounds the outer periphery of the MEGA 110 and is subjected to cooling curing. As a result, the outer edge 123 of the anode separator 120 and the outer edge 138 of the cathode separator 130 face each other with the adhesive seal 140 interposed therebetween, and the MEGA 110 is sealed on the outer peripheral edge side by the adhesive seal 140. After the formation of the adhesive seal 140, the adhesive seal 140 is formed by a punching tool or the like at the gas / cooling water supply / discharge hole forming portion of the separator so as to connect the supply / discharge hole from the anode side separator 120 to the cathode side separator 130. Are punched out to form an oxidant gas discharge hole 124OT, an oxidant gas supply hole 124IN, and the like.

  When the unit cell 100 shown in FIG. 5 is obtained in this way, as shown in FIG. 7, a plurality of unit cells 100 are stacked and fastened with the fastening bolts 20 shown in FIG. 1 so that a fastening load is applied to each part of the cell surface. . At this time, before the fastening, the difference ΔH described above remains in each unit cell 100 between the convex portion 123t and the first groove 202, but the unit cell 100 receives the fastening load, The adhesive seal 140 is compressed at the convex portion 123t so that the difference ΔH becomes zero, and then each bottom wall 202s of the first groove 202 is brought into contact with the cathode-side separator 130 of the adjacent unit cell 100. Thereby, the fuel cell 10 having the stack structure shown in FIG. 4 is obtained.

  FIG. 8 is a schematic perspective view schematically showing the state of the separator corner portion D shown in FIG. As shown in the figure, the unit cell 100 of this embodiment includes an outer edge portion 123 (specifically, a convex portion 123t) of the anode-side separator 120 and an outer edge portion 138 of the cathode-side separator 130 that sandwich the MEGA 110 with an adhesive seal 140 interposed therebetween. In addition, a connector mounting portion 125 and a connector mounting portion 135 are provided, and both the mounting portions are opposed to each other with an adhesive seal 140 interposed therebetween. Then, the cell monitor connector measures the potential measuring unit 130Ct in a state where the cell monitor connector is mounted on the connector mounting portion 125 and the connector mounting portion 135 and is removed by this mounting portion in units of a predetermined number of unit cells 100. It is clamped at the terminal and outputs the measured potential.

  As shown in FIG. 5, the unit cell 100 according to the present embodiment has outer edge portions (hereinafter referred to as separator outer edge portions) of the anode-side separator 120 and the cathode-side separator 130 facing each other with a rubber adhesive seal 140 interposed therebetween. ), More specifically, the thickness Ht of the convex portion 123t and the outer edge portion 138 at the outer edge portion 123 is applied to the cathode side separator 130 from the anode side separator 120 sandwiching the MEGA 110 in the separator central region 121 and the separator central region 137. The cell thickness Hs is larger. Therefore, the load based on the cell fastening force by the fastening bolt 20 and other fastening bolts is increased at the separator outer edge portion with the rubber adhesive seal 140 interposed. As a result, according to the unit cell 100 of the present embodiment, even if the adhesive seal 140 is drooped or contracted in volume, the load applied to the outer edge of the separator with the adhesive seal 140 interposed is large. In the battery 10, in the unit cell 100 adjacent to each other, expansion of the gap between the separators at the outer edge of the separator can be suppressed, and the sealing performance between the cells can be maintained. Further, in the unit cell 100 of this embodiment, the thickness of the outer edge of the separator may be increased, and the thickness Ht of the outer edge of the separator can be easily increased by adjusting the shape of the separator, and eventually by adjusting the shape of the press die. it can. Therefore, according to the unit cell 100 of the present embodiment, it is possible to reduce the cell manufacturing cost, and thus the manufacturing cost as the fuel cell 10, as well as the simple adjustment of the shape of the separator and the shape of the press die. The sealing performance between the adjacent unit cells 100 can be reliably maintained.

  In the unit cell 100 of this embodiment, the thickness Ht of the separator outer edge when the cell is alone is made larger than the thickness of the separator outer edge of the unit cell 100 included in the stack structure in which the plurality of unit cells 100 are stacked. For this reason, since the load based on the fastening force is surely increased at the separator outer edge portion by an amount corresponding to the difference from the thickness of the separator outer edge portion in the stack structure, the sealing performance between the cells can be maintained as described above.

  In the unit cell 100 of this embodiment, both the anode-side separator 120 and the cathode-side separator 130 are made of a metal steel plate such as stainless steel and titanium, and the separator outer edge portion, in detail, the anode-side separator is opposed to both the separators. The outer edge 123 of 120 has a protrusion 123t protruding outward from the cell, and the thickness Ht of the separator outer edge is defined by the protrusion 123t. FIG. 9 is an explanatory view schematically showing the state of the convex portion 123t accompanying the compression of the adhesive seal 140. FIG. As shown in the figure, the protrusion 123t is formed so that the above separators are formed through press molding of a metal steel plate and protrudes outward from the cell, so that the difference ΔH is zero due to the fastening load of the adhesive seal 140. When compressed, it functions as a spring that stores its elasticity. Therefore, according to the unit cell 100 of this embodiment, since the spring function of the convex portion 123t can resist the settling and volume shrinkage of the adhesive seal 140, the sealing performance between the cells can be maintained with high effectiveness. .

  As shown in FIG. 8, the unit cell 100 of this embodiment includes an outer edge portion 123 and an outer edge portion 138 of both the anode-side separator 120 and the cathode-side separator 130, and a connector attachment portion 125 in which a cell monitor connector is attached. 135, both of these connector mounting portions are opposed to each other with an adhesive seal 140 interposed therebetween. By doing so, the thickness of the connector mounting portions 125 and 135 with the rubber adhesive seal 140 interposed therebetween can be made larger than the cell thickness Hs (see FIG. 5) described above. In the fuel cell 10, expansion of the gap between the connector mounting portions in the adjacent unit cells 100 can be suppressed. Therefore, according to the unit cell 100 of the present embodiment, the cell monitor connector can be mounted on the connector mounting portions 125 and 135 without hindrance, and the connector can be prevented from being dropped and the connector from being damaged or broken.

  In the fuel cell 10 according to the present embodiment, when stacking a plurality of unit cells 100 in which the MEGA 110 is sandwiched between the anode-side separator 120 and the cathode-side separator 130, the anode-side separator 120 of one unit cell 100 is adjacent to the unit cell 100. The cathode side separator 130 of the other unit cell 100 is pressed so as to come into contact with each other, and the load applied to the outer edge portion 123 and the outer edge portion 138 of both separators with the rubber elastic sealing material 140 interposed therebetween is the separator central region 121 of both separators. Fastening is performed so as to be larger than the load applied to 137. Therefore, according to the fuel cell 10 of the present embodiment, even if the elastic seal material 140 made of rubber is drooped or contracted in volume, it is applied to the outer edge portion 123 and the outer edge portion 138 with the elastic seal material 140 interposed therebetween. Since the load is large, the expansion of the gap between the separators in the adjacent unit cells 100 can be suppressed, and the sealing performance between the cells can be maintained.

  In the fuel cell 10 of the present embodiment, each unit cell 100 itself to be stacked has a separator outer edge thickness Ht with a rubber adhesive seal 140 interposed therebetween, which is larger than the cell thickness Hs, and is based on the cell fastening force. The load is set to be larger than the separator central regions 121 and 137 at the separator outer edge portion where the adhesive seal 140 is interposed. Therefore, according to the fuel cell 10 of the present embodiment, since the existing unit cell may be replaced with the unit cell 100 of the present embodiment, the fuel cell manufacturing cost can be reduced in addition to maintaining the sealing performance between the cells.

  The present invention is not limited to the above-described embodiment, and can be realized with various configurations without departing from the spirit of the present invention. For example, the technical features of the embodiments corresponding to the technical features in each embodiment described in the summary section of the invention are intended to solve part or all of the above-described problems, or part of the above-described effects. Or, in order to achieve the whole, it is possible to replace or combine as appropriate. Further, if the technical feature is not described as essential in the present specification, it can be deleted as appropriate.

  In the unit cell 100 of the above-described embodiment, the cathode side separator 130 is a flat plate separator. However, in the adjacent unit cells 100, the anode side separator 120 of one unit cell 100 is the cathode side separator of the other unit cell 100. The shape of the cathode-side separator 130 is not limited to a flat plate shape as long as it is pressed to contact 130 and forms a flow path as described above. FIG. 10 is an explanatory view schematically showing the dimensional relationship of each component member of a unit cell 100A of another embodiment, and FIG. 11 shows the fuel cell 10A of another embodiment corresponding to FIG. It is a schematic cross section shown in cross section. As shown in FIG. 10, the unit cell 100 </ b> A includes the first grooves 303 and the second grooves 304 alternately arranged in the central region 137 of the separator, similarly to the anode separator 120, even in the cathode separator 130. The outer edge portion 138 includes a convex portion 138t. Even in the unit cell 100A, in the single cell state, the outer edge 123 of the anode separator 120 and the outer edge 138 of the cathode separator 130 are opposed to each other with the adhesive seal 140 interposed therebetween as described above. Yes. In addition, the unit cell 100A has a thickness Ht (thickness Ht of the separator outer edge portion) between the convex portions 123t and 138t facing each other from the anode-side separator 120 that sandwiches the MEGA 110 in the separator central regions 121 and 137. The cell thickness Hs on the cathode-side separator 130 is larger. In the unit cell 100A of this embodiment, the thickness Ht of the separator outer edge is large on both sides of the cell, so that there is a difference in thickness by one half of the difference ΔH described above on one cell surface.

  In obtaining the unit cell 100A shown in FIG. 10, following the procedure described in FIG. 6, the placement of the rubber material 140m at the location where the adhesive seal 140 is formed and the predetermined pressure on the cathode side separator 130 side. Then, the anode side separator 120 is pressed to bring both bottom walls of the second groove 204 and the second groove 304 into contact with the MEGA 110. In this state, the rubber material 140m is heated and melted, and the rubber material 140m surrounds the outer periphery of the MEGA 110 and is subjected to cooling curing. As a result, the unit cell 100A shown in FIG. 10 is obtained, and a plurality of the obtained unit cells 100A are stacked and fastened with the fastening bolts 20 shown in FIG. 1 so that a fastening load is applied to each part of the cell surface. At this time, each unit cell 100A is subjected to a fastening load, and after compressing the adhesive seal 140 at the convex portion 123t and the convex portion 138t so that the difference ΔH / 2 is zero on both sides of the cell, Each bottom wall 202s of the first groove 202 is brought into contact with each bottom wall 303s of the first groove 303 of the cathode separator 130 of the adjacent unit cell 100A. As a result, the fuel cell 10A having the stack structure shown in FIG. 11 is obtained.

  Even in the unit cell 100A and the fuel cell 10A of the above-described embodiment, effects such as maintaining the sealing performance and the spring function described with reference to FIG. 9 can be achieved.

  In addition, a thin-leaf metal sheet is mounted on the top surface of the convex portion 123t of the above-described embodiment, and the thickness Ht of the outer edge including the metal sheet is made larger than the cell thickness Hs between the separators in the separator central region 121. It may be.

DESCRIPTION OF SYMBOLS 10, 10A ... Fuel cell 20 ... Fastening bolt 100, 100A ... Unit cell 110 ... MEGA
110A ... Anode-side gas diffusion layer 110C ... Cathode-side gas diffusion layer 110D ... MEA
DESCRIPTION OF SYMBOLS 112 ... Power generation area | region 120 ... Anode side separator 120c ... Cutting part 121 ... Separator center area | region 122IN ... Fuel gas supply hole 122OT ... Fuel gas discharge hole 123 ... Outer edge part 123t ... Protrusion part 124IN ... Oxidant gas supply hole 124OT ... Oxidant gas Discharge hole 125 ... Connector mounting part 126IN ... Cooling water supply hole 126OT ... Cooling water discharge hole 127 ... Guide convex part 130 ... Cathode side separator 130Ct ... Potential measuring part 131 ... Leg 132IN ... Fuel gas supply hole 132OT ... Fuel gas discharge hole 134IN ... Oxidant gas supply hole 134OT ... Oxidant gas discharge hole 135 ... Connector mounting portion 136IN ... Cooling water supply hole 136OT ... Cooling water discharge hole 137 ... Separator central region 138 ... Outer edge part 138t ... Convex part 140 ... Adhesive seal (elastic seal) Wood)
140m ... rubber material 141 ... power generation region window 142IN ... fuel gas supply hole 142OT ... fuel gas discharge hole 144IN ... oxidant gas supply hole 144OT ... oxidant gas discharge hole 146IN ... cooling water supply hole 146OT ... cooling water discharge hole 150 ... gas Flow path member 151 ... Sealing sheet 160E ... Terminal plate 160F ... Terminal plate 165E ... Insulating plate 165F ... Insulating plate 170E ... End plate 170F ... End plate 172IN ... Fuel gas supply hole 172OT ... Fuel gas discharge hole 174IN ... Oxidant gas supply hole 174OT ... Oxidant gas discharge hole 176IN ... Cooling water supply hole 176OT ... Cooling water discharge hole 200 ... Fuel gas flow path 202 ... First groove (fuel gas flow path groove)
202s ... bottom wall 202t ... end first groove 204 ... second groove (cooling water channel groove)
DESCRIPTION OF SYMBOLS 300 ... Fuel gas sealing material 301 ... Oxidant sealing material 302 ... Cooling water sealing material 303 ... 1st groove | channel 303s ... Bottom wall 304 ... 2nd groove | channel A ... Conversion area | region D ... Separator corner part Hs ... Cell thickness Ht ... Separator outer edge thickness Hsa ... groove depth Hta ... projection height

Claims (4)

A fuel battery cell in which a membrane electrode assembly is sandwiched between a first separator and a second separator,
A sheet-like elastic sealing material that surrounds the membrane electrode assembly so as to expose the power generation region of the membrane electrode assembly and seals the membrane electrode assembly on the outer peripheral side of the membrane electrode assembly;
The first and second separators are:
The film respectively provided from the power generation region facing the separator central region of the electrode assembly outer edge portion extending around the outer edge, the outer edge portion over the region of the outer edges are opposed by interposing the elastic-seal material,
The thickness of the outer edge portion of the over from the first separator in the outer edge portion in which the bullet seal member is opposed interposed the second separator, the membrane electrode assembly in the separator central region A thickness of the fuel cell that is larger than a thickness of the first separator sandwiched between the second separator and the second separator. The first and second separators are formed from a metal steel plate,
Wherein the first and the outer edge portion where the second separator is by the counter, it has a convex portion protruding toward the cell Le outward in the cell thickness direction, defining the thickness of the outer edge at the convex portion The fuel battery cell according to claim 1 . Said first and second separator, the outer edge portion, provided with a connector mounting portion cell monitor connector is mounted, even in the connector mounting portion, the connector mounting portion to each other interposing the pre-Symbol elastic sealing member The fuel cell according to claim 1, wherein the fuel cell faces each other. A fuel cell in which a plurality of fuel cells each having a membrane electrode assembly sandwiched between a first separator and a second separator are stacked,
Each of the fuel cells is a fuel cell according to any one of claims 1 to 3,
The second separator of the other fuel battery cell comes into contact with and is pressed against the first separator of one fuel battery cell of the adjacent fuel battery cells, and the load applied to the outer edge portion is the central region of the separator A fuel cell that is fastened to be larger than the load applied to the fuel cell.

Images