JP4545725B2 - Fuel cell - Google Patents

Description

  The present invention relates to a fuel cell in which an electrode membrane structure composed of a solid polymer electrolyte membrane and anode-side diffusion electrodes and cathode-side diffusion electrodes on both sides thereof is sandwiched by a pair of separators. The present invention relates to a fuel cell that can reliably seal an electrode membrane structure between them.

  Some fuel cells have a structure in which an electrode membrane structure composed of a solid polymer electrolyte membrane and anode-side diffusion electrodes and cathode-side diffusion electrodes on both sides thereof is sandwiched between a pair of separators. When fuel gas (for example, hydrogen gas) is supplied to the reaction surface of the anode side diffusion electrode, hydrogen is ionized here and moves to the cathode electrode side through the solid polymer electrolyte membrane. Electrons generated during this time are taken out to an external circuit and used as direct current electric energy. Since an oxidizing gas (for example, air containing oxygen) is supplied to the cathode electrode, hydrogen ions, electrons, and oxygen react to generate water.

An example of this will be described with reference to FIG. 20. In the figure, 1 indicates a solid polymer electrolyte membrane, and the solid polymer electrolyte membrane 1 is sandwiched between gas diffusion electrodes (anode side diffusion electrode and cathode side diffusion electrode) 2 and 3 from both sides. Thus, the fuel battery cell 4 is configured. A pair of separators 5, 5 are arranged on both surfaces of the fuel cell 4, and an O-ring 7 is set in a groove 6 formed in each separator 5, and the solid polymer electrolyte membrane 1 is formed by the O-ring 7. In this state, the fuel cells 4 are sandwiched between the separators 5 and 5 (see Patent Document 1).
JP-A-8-148169

In the conventional fuel cell, the space between the separator 5 and the gas diffusion electrodes 2 and 3 is blocked from the outside by the O-ring 7, so that the fuel gas and the oxidizing gas do not leak to the outside. In addition, since both of them are not mixed, it is excellent in that power generation can be performed without waste. However, when the positions of the O-rings 7 are slightly shifted from each other, a sufficient seal reaction force is obtained by this shift. In addition, there is a possibility that the sealing performance may be impaired, and when the thin solid polymer electrolyte membrane 1 is pulled up and down in FIG. There is a problem that a force in the peeling direction acts between the gas diffusion electrodes 2 and 3 and is not preferable.
Therefore, in order to avoid this, there is a problem that the dimensional accuracy of the groove 6 must be strictly managed, leading to an increase in cost.
Therefore, the present invention provides a fuel cell that can improve the sealing performance between the electrode membrane structure and the separator.

In order to solve the above problems, the invention described in claim 1 is directed to a solid polymer electrolyte membrane (for example, the solid polymer electrolyte membrane 18 in the embodiment) and anode-side diffusion electrodes on both sides thereof (for example, the anode in the embodiment). An electrode membrane structure (for example, a fuel cell in the embodiment) composed of the electrode 22 and the second gas diffusion layer 26) and a cathode side diffusion electrode (for example, the cathode electrode 20 and the first gas diffusion layer 24 in the embodiment) 12) is sandwiched between a pair of separators (for example, the first separator 14 and the second separator 16 in the embodiment), and the anode side diffusion electrode and the cathode side diffusion electrode are connected to either one of them. The electrode film structure is formed so that the surface of the anode side diffusion electrode and the cathode side diffusion electrode are larger than the other side surface. A first seal (for example, the first seal S1 in the embodiment) is provided between the outer peripheral portion of the product diffusion electrode and the one separator so as to surround the diffusion electrode having a small surface area. A second seal (for example, the second seal S2 in the embodiment) is provided so as to surround the diffusion electrode having a large surface area.
By comprising in this way, it becomes possible to make a 1st seal | sticker and a 2nd seal | sticker function independently from each other in a different position.

The invention described in claim 2 is characterized in that the solid polymer electrolyte membrane is formed smaller than the diffusion electrode having the large surface area.
By comprising in this way, an expensive solid polymer electrolyte membrane can be made small.

The invention described in claim 3 is characterized in that at least the first seal or the second seal is in close contact with either end face of the anode side diffusion electrode or the cathode side diffusion electrode.
By comprising in this way, the outflow of the reactive gas from an end surface can be blocked | prevented by the 1st or 2nd seal | sticker closely_contact | adhered to the said end surface.

The invention described in claim 4 is characterized in that the first seal is in close contact with an end face of the diffusion electrode having the small surface area and further spreads to the same area as the diffusion electrode having the large surface area.
By comprising in this way, while the 1st seal | sticker closely_contact | adhered to the said end surface can prevent outflow of the reactive gas from an end surface, the space part between 2nd seals can be eliminated, and anode side Of the diffusion electrode and the cathode side diffusion electrode, the diffusion electrode having a large surface area can be reliably supported by the first seal.

The invention described in claim 5 is characterized in that the second seal is in close contact with both end faces of the first seal and the diffusion electrode having a large surface area.
With this configuration, the second seal that is in close contact with both end surfaces of the first seal and the large surface area diffusion electrode prevents the reaction gas from flowing out from the end surface of the large surface area diffusion electrode. In addition, the space between the first seal and the first seal can be eliminated, and a diffusion electrode having a large surface area of the anode-side diffusion electrode and the cathode-side diffusion electrode can be reliably supported by the first seal.

The invention described in claim 6 is characterized in that the solid polymer electrolyte membrane and the large surface area diffusion electrode have the same size.
By comprising in this way, after manufacturing a solid polymer electrolyte membrane and the said large surface area diffusion electrode, it can manufacture by cut | disconnecting the outer peripheral part and making it flush | planar.

The invention described in claim 7 is characterized in that the size of the catalyst portion of the diffusion electrode having the large surface area is the same as the size of the catalyst portion of the diffusion electrode having the small surface area.
By comprising in this way, the expensive catalyst part which does not contribute to reaction can be reduced.

As in the invention described in claim 8, the separator may be made of dense carbon, or in the invention described in claim 9, the separator (for example, the first separator 114, the first separator in the embodiment, 2 separator 116) may be made of a thin metal plate.
When the separator is made of a thin metal plate, it can be easily manufactured by press molding, and the productivity is improved.

According to a tenth aspect of the present invention, the first seal (for example, the first seal S11 in the embodiment) and the second seal (for example, the second seal S12 in the embodiment) are integrally formed on the separator. It is characterized by being.
By comprising in this way, both seals can be manufactured in one process.

The invention described in claim 11 is characterized in that the first seal and the second seal are provided in separate separators.
By comprising in this way, the seal | sticker of a different material can each be used with respect to each metal separator.

As described above, according to the first aspect of the present invention, the first seal and the second seal can be made to function independently from each other at different positions, so that they face each other at the same position. Compared with the case, there is no effect such as the occurrence of seal breakage due to positional deviation, and there is an effect that the gap between the electrode film structure and the separator can be surely sealed. In addition, when facing each other at the same position, it was limited to the same material in order to equalize the reaction force, but since the reaction force is not exerted on each other, the material can be freely set, and the freedom of setting the material is There is an increased effect.
According to the second aspect of the present invention, there is an effect that the solid polymer electrolyte membrane and the overall cost can be reduced by the amount that can reduce the expensive solid polymer electrolyte membrane.
According to the invention described in claim 3, since the outflow of the reaction gas from the end surface can be prevented by the first or second seal closely adhered to the end surface, the reaction gas blows out to the outlet side without passing through the power generation surface. There is an effect that the sealing performance can be further improved.
According to the fourth aspect of the present invention, the first seal that is in close contact with the end face can prevent the reaction gas from flowing out from the end face, and the space between the second seal and the second seal can be eliminated. Therefore, it is possible to prevent the reactive gas from blowing through to the outlet side without passing through the power generation surface, and to further improve the sealing performance, and to eliminate the space between the first seal and the second seal, There is an effect that unnecessary pressure can be prevented from acting on the seal portion due to expansion and contraction of the space portion at the time.
According to the fifth aspect of the present invention, in addition to the above effect, the first gas and the second gas seal can prevent the reaction gas from flowing out from both end faces of the diffusion electrode. There is an effect that the sealing performance can be further improved by preventing the air from passing through to the outlet side.
According to the invention described in claim 6, since the solid polymer electrolyte membrane and the diffusion electrode having a large surface area are integrated, the outer peripheral portion can be cut to be flush with each other. There is an effect that can.
According to the invention described in claim 7, since an expensive catalyst portion that does not contribute to the reaction can be reduced, the manufacturing cost can be reduced.
The separator may be made of dense carbon as in the invention described in claim 8, or the separator may be made of a thin metal plate as in invention of claim 9. When the separator is made of a thin metal plate as in the invention described in claim 9, it can be easily manufactured by press molding, so that the productivity can be improved.
According to the invention described in claim 10, since both the seals can be manufactured in one step, there is an effect that the number of manufacturing steps can be reduced.
According to the eleventh aspect of the present invention, since different seals of different materials can be used for each metallic separator, there is an effect that the degree of freedom in design is increased.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is an exploded perspective view showing a fuel cell according to an embodiment of the present invention. The fuel cell 10 includes a fuel cell (electrode membrane structure) 12 and first and second separators 14 and 16 made of dense carbon that sandwich the fuel cell 10, and a plurality of these are laminated to form a fuel cell stack for a vehicle. Is constituted.
The fuel cell 12 includes a solid polymer electrolyte membrane 18 and a cathode electrode 20 and an anode electrode 22 that are disposed with the solid polymer electrolyte membrane 18 interposed therebetween. For example, a first gas diffusion layer 24 and a second gas diffusion layer 26 made of porous carbon cloth or porous carbon paper, which are porous layers, are disposed. Here, a perfluorosulfonic acid polymer is used as the solid polymer electrolyte membrane 18. The cathode electrode 20 and the anode electrode 22 are catalysts mainly composed of Pt. The cathode electrode 20 and the first gas diffusion layer 24 constitute a cathode side diffusion electrode, and the anode electrode 22 and the second gas diffusion layer 26 constitute an anode side diffusion electrode.

As shown in FIG. 6, the solid polymer electrolyte membrane 18 slightly protrudes from the outer periphery of the cathode electrode 20, the first gas diffusion layer 24, the anode electrode 22, and the second gas diffusion layer 26 disposed therebetween. The anode electrode 22 and the second gas diffusion layer 26 have a smaller surface area than the solid polymer electrolyte membrane 18, and the cathode electrode 20 and the first gas diffusion layer 24 have the anode electrode 22 and the second gas diffusion layer. The surface area is smaller than 26. The solid polymer electrolyte membrane 18, the cathode electrode 20, the first gas diffusion layer 24, the anode electrode 22, and the second gas diffusion layer 26 coincide with each other in the center portion, and have a dimensional difference in the vertical direction and the horizontal direction in FIG. The ratio is set to be equal.
As shown in FIG. 3, the first separator 14 has an inlet-side fuel gas communication hole for allowing a fuel gas such as a hydrogen-containing gas to pass through the upper ends of both lateral ends located in the outer peripheral edge within the plane. 36a and an inlet side oxidant gas communication hole 38a for allowing an oxidant gas, which is an oxygen-containing gas or air, to pass therethrough.

  An inlet-side cooling medium communication hole 40a for passing a cooling medium such as pure water, ethylene glycol, or oil, and an outlet for allowing the used cooling medium to pass through are provided at the center of both lateral ends of the first separator 14. A side cooling medium communication hole 40b is provided. Further, an outlet-side fuel gas communication hole 36b for allowing the fuel gas to pass therethrough and an outlet for allowing the oxidant gas to pass to the lower portions of both ends in the lateral direction located in the outer peripheral edge portion within the plane of the first separator 14 The side oxidant gas communication hole 38b is provided so as to be diagonal to the inlet side fuel gas communication hole 36a and the inlet side oxidant gas communication hole 38a.

  As shown in FIG. 1, on the surface 14a of the first separator 14 facing the cathode electrode 20, a plurality of, for example, six independent first oxidizers are provided in the vicinity of the inlet-side oxidant gas communication hole 38a. The gas flow path groove 42 is provided in the direction of gravity while meandering in the horizontal direction. The first oxidant gas flow channel 42 joins the three second oxidant gas flow channels 44, and the second oxidant gas flow channel 44 is adjacent to the outlet side oxidant gas communication hole 38b. It is terminated.

  As shown in FIG. 3, the first separator 14 penetrates through the first separator 14, and one end thereof communicates with the inlet-side oxidant gas communication hole 38a on the surface 14b opposite to the surface 14a. A first oxidant gas connection channel 46 whose end communicates with the first oxidant gas channel groove 42 on the surface 14a side, and one end communicates with the outlet side oxidant gas communication hole 38b on the surface 14b side, A second oxidant gas connection channel 48, the other end of which communicates with the second oxidant gas channel groove 44 on the surface 14a side, is provided through the first separator 14.

  As shown in FIGS. 4 and 5, the inlet-side fuel gas communication hole 36 a and the inlet are formed on both ends in the lateral direction within the plane of the second separator 16 and located on the outer peripheral edge, as with the first separator 14. A side oxidant gas communication hole 38a, an inlet side cooling medium communication hole 40a, an outlet side cooling medium communication hole 40b, an outlet side fuel gas communication hole 36b, and an outlet side oxidant gas communication hole 38b are formed.

In the surface 16a of the second separator 16, a plurality of, for example, six first fuel gas passage grooves 60 are formed in the vicinity of the inlet side fuel gas communication hole 36a. The first fuel gas flow channel 60 extends in the direction of gravity while meandering in the horizontal direction, and merges with the three second fuel gas flow channels 62 to form the second fuel gas flow channel 62. Terminates in the vicinity of the outlet side fuel gas communication hole 36b.
The second separator 16 includes a first fuel gas connection channel 64 that communicates the inlet side fuel gas communication hole 36a from the surface 16b side to the first fuel gas channel groove 60, and an outlet side fuel gas communication hole 36b. A second fuel gas connection channel 66 communicating with the second fuel gas channel groove 62 from the surface 16 b side is provided through the second separator 16.

As shown in FIGS. 2 and 5, the surface 16 b of the second separator 16 is close to the inlet side cooling medium communication hole 40 a and the outlet side cooling medium communication hole 40 b within a range surrounded by a seal S described later. A plurality of main flow path grooves 72a and 72b constituting the cooling medium flow path are formed. Between the main flow path grooves 72a and 72b, branch flow path grooves 74 that branch into a plurality of lines are provided extending in the horizontal direction.
The second separator 16 has a first cooling medium connection channel 76 that communicates the inlet side cooling medium communication hole 40a and the main channel groove 72a, and an outlet side cooling medium communication hole 40b and the main channel groove 72b that communicates with each other. A second cooling medium connection channel 78 is provided through the second separator 16.

  Here, as shown in FIG. 4, the inlet side fuel gas communication hole 36a, the inlet side oxidant gas communication hole 38a, the inlet side cooling medium communication hole 40a, and the outlet side cooling medium communication hole 40b of the surface 16a of the second separator 16 are provided. A groove 30 is formed around the outlet side fuel gas communication hole 36 b and the outlet side oxidant gas communication hole 38 b, and a seal S is attached to the groove 30. Here, the grooves 30 around the inlet side cooling medium communication hole 40a and the outlet side cooling medium communication hole 40b are formed so as to surround the first cooling medium connection channel 76 and the second cooling medium connection channel 78, respectively. Has been.

  5, the inlet-side fuel gas communication hole 36a, the inlet-side oxidant gas communication hole 38a, the inlet-side cooling medium communication hole 40a, the outlet-side cooling medium communication hole 40b, the surface 16b of the second separator 16, A groove 35 is also formed around the outlet-side fuel gas communication hole 36 b and the outlet-side oxidant gas communication hole 38 b, and a seal S is also attached to the groove 35. Here, the grooves 35 around the inlet side fuel gas communication hole 36a and the outlet side fuel gas communication hole 36b are formed so as to surround the first fuel gas connection channel 64 and the second fuel gas connection channel 66, respectively. Has been. A groove 35 around the inlet-side oxidant gas communication hole 38a and the outlet-side oxidant gas communication hole 38b is connected to the inlet-side oxidant gas communication hole 38a and the outlet-side oxidant gas communication hole of the surface 14b of the first separator 14. It is provided so as to surround the hole 38b.

2 and 3, the surface 14a of the first separator 14 surrounds the first oxidant gas communication channel groove 42 and the second oxidant gas communication channel groove 44, and has a solid height. A first seal S <b> 1 is attached so as to be in close contact with the molecular electrolyte membrane 18 and surround the cathode electrode 20.
A second seal S2 is attached to the surface 14a of the first separator 14 around the first seal S1. The second seal S2 is in close contact with the surface 16a of the second separator 16, and the anode The electrode 22 is surrounded.

  Therefore, as shown in FIGS. 2 and 7, when the fuel cell 12 is sandwiched between the first separator 14 and the second separator 16, the surface 14a of the first separator 14 and the surface 16a of the second separator 16 are The provided inlet side fuel gas communication hole 36a, the inlet side oxidant gas communication hole 38a, the inlet side cooling medium communication hole 40a, the outlet side cooling medium communication hole 40b, the outlet side fuel gas communication hole 36b, and the outlet side oxidant gas communication The seals S of the grooves 30 around the hole 38b are in close contact with each other so that the inlet side fuel gas communication hole 36a, the inlet side oxidant gas communication hole 38a, the inlet side cooling medium communication hole 40a, the outlet side cooling medium communication hole 40b, The periphery of the outlet-side fuel gas communication hole 36b and the outlet-side oxidant gas communication hole 38b is sealed, and the fuel cell is provided by the first seal S1 and the second seal S2. It can be reliably sealed around the 2.

  Also, as shown in FIG. 5, the surface 16b of the second separator 16 is a position facing the surface 14b of the first separator 14 when a plurality of fuel cells 10 are stacked, A groove 34 surrounding the periphery of 74 is provided, and a seal S is attached to the groove 34.

  In this way, when the fuel cells 10 are stacked, if the surface 14b of the first separator 14 and the surface 16b of the second separator 16 are polymerized, the inlet-side fuel gas communication hole 36a and the inlet-side oxidant gas communication hole 38a. The inlet side cooling medium communication hole 40a, the outlet side cooling medium communication hole 40b, the outlet side fuel gas communication hole 36b, the outlet side oxidant gas communication hole 38b, and the branch flow path groove 74 are arranged on the second separator 16 side. Since the seal S is in close contact with the surface 14 b of the first separator 14, water tightness between the first separator 14 and the second separator 16 is ensured.

  Here, the seal S, the first seal S1, and the second seal S2 are molded from silicon rubber (for example, hardness of about 50 °), and any of non-adhesiveness and adhesiveness can be used. It should be noted that it is desirable to use a non-adhesive seal S for a portion that needs to be replaced for maintenance, for example, the surface 14b of the first separator 14 and the surface 16b of the second separator 16.

The operation of the fuel cell 10 according to the first embodiment configured as described above will be described below.
The fuel cell 10 is supplied with a fuel gas, for example, a gas containing hydrogen obtained by reforming hydrocarbons, and is supplied with air or an oxygen-containing gas (hereinafter also simply referred to as air) as an oxidant gas. A cooling medium is supplied to cool the power generation surface. The fuel gas supplied to the inlet-side fuel gas communication hole 36a of the fuel cell 10 moves from the surface 16b side to the surface 16a side via the first fuel gas connection channel 64, as shown in FIG. The first fuel gas channel groove 60 formed on the 16a side is supplied.

  The fuel gas supplied to the first fuel gas channel groove 60 moves in the direction of gravity while meandering in the horizontal direction along the surface 16a of the second separator 16. At that time, the hydrogen-containing gas in the fuel gas is supplied to the anode-side electrode 22 of the unit fuel cell 12 through the second gas diffusion layer 26. Unused fuel gas is supplied to the anode-side electrode 22 while moving along the first fuel gas channel groove 60, while unused fuel gas passes through the second fuel gas channel groove 62. After being introduced into the second fuel gas connection channel 66 and moving to the surface 16b side, it is discharged to the outlet side fuel gas communication hole 36b shown in FIG.

  The air supplied to the inlet-side oxidant gas communication hole 38a in the fuel cell stack 10 passes through the first oxidant gas connection channel 46 that communicates with the inlet-side oxidant gas communication hole 38a of the first separator 14. Are introduced into the first oxidant gas channel groove 42. While the air supplied to the first oxidant gas flow channel 42 moves in the gravity direction while meandering in the horizontal direction, the oxygen-containing gas in the air is supplied from the first gas diffusion layer 24 to the cathode side electrode 20. Is done. On the other hand, unused air is discharged from the second oxidant gas connection channel 48 through the second oxidant gas channel groove 44 to the outlet side oxidant gas communication hole 38b shown in FIG. As a result, the fuel cell 10 generates power, and for example, power is supplied to a motor (not shown).

  Furthermore, after the cooling medium supplied to the fuel cell 10 is introduced into the inlet side cooling medium communication hole 40a shown in FIG. 1, as shown in FIG. 5, the first cooling medium connection flow path of the second separator 16 is used. It is supplied to the main flow path groove 72a on the surface 16b side through 76. The cooling medium cools the power generation surface of the unit fuel cell 12 through a plurality of branch channel grooves 74 branched from the main channel groove 72a, and then merges with the main channel groove 72b. Then, the used cooling medium is discharged from the outlet side cooling medium communication hole 40 b through the second cooling medium connection channel 78.

According to the above embodiment, the cathode electrode 20 and the first gas diffusion are achieved by the first seal S1 interposed between the surface 14a of the first separator 14 and the anode electrode 22 via the solid polymer electrolyte membrane 18. The periphery of the layer 24 can be surely sealed, and the anode electrode 22 and the second electrode S2 are provided by the second seal S2 interposed between the surface 14a of the first separator 14 and the surface 16a of the second separator 16. Since the periphery of the two-gas diffusion layer 26 can be reliably sealed, the first seal S1 and the second seal S2 can function independently of each other. Therefore, as compared with a case where sealing is performed by pressing each other with the O-rings facing each other, there is no longer any seal breakage due to positional deviation, and sealing can be performed reliably.
Also, when facing each other at the same position, it was limited to the same material in order to equalize the reaction force, but since the reaction force is not exerted on each other, the material can be freely set, and the freedom of setting the material is Enhanced.

The first seal S1 does not apply a force that causes kinking by the solid polymer electrolyte membrane 18, and the second seal S2 does not contact the fuel cell 12. Therefore, the force in the peeling direction does not act on the solid polymer electrolyte membrane 18.
Furthermore, since it is not necessary to match the arrangement positions of the first seal S1 and the second seal S2, dimensional accuracy management is facilitated, work can be easily performed, and costs can be reduced.
Further, since the cross-sectional area of the second seal S2 can be increased, the amount of elastic deformation can be increased and the sealing performance can be improved.

Next, FIG. 8 shows a second embodiment of the present invention.
In this embodiment, the surface area of the anode electrode 22 and the second gas diffusion layer 26 is larger than the surface area of the solid polymer electrolyte membrane 18, that is, the solid polymer electrolyte membrane 18 is the anode electrode 22 and the second gas diffusion layer 26. It is different in that it is formed with a smaller surface area than (a diffusion electrode having a larger surface area among the anode side diffusion electrode and the cathode side diffusion electrode). This embodiment also has an effect that can be surely sealed by the first seal S1 and the second seal S2 as in the first embodiment. In addition, the same code | symbol is attached | subjected to the part same as 1st Embodiment, and description is abbreviate | omitted. In this embodiment, a part of the solid polymer electrolyte membrane 18 that protrudes from the second gas diffusion layer 26 is not necessary, so that the expensive solid polymer electrolyte membrane 18 can be made small. Therefore, the cost of the solid polymer electrolyte membrane 18 is reduced. Can be lowered.

Next, FIG. 9 shows a third embodiment of the present invention.
In this embodiment, the first seal S1 interposed between the surface 14a of the first separator 14 and the anode electrode 22 via the solid polymer electrolyte membrane 18 is used for the cathode electrode 20 and the first gas diffusion layer 24. It is arranged in close contact with the end face. According to this embodiment, the outflow of the reaction gas from the end surfaces of the cathode electrode 20 and the first gas diffusion layer 24 can be prevented, and the reaction gas is prevented from blowing through to the outlet side without passing through the power generation surface. There is an effect of improving the sealing performance.

Next, FIG. 10 shows a fourth embodiment of the present invention.
In this embodiment, the first seal S1 is disposed at the same position as in the third embodiment, and the second seal S2 is brought into contact with the end faces of the first seal S1, the anode electrode 22 and the second gas diffusion layer 26. It is arranged in contact. According to this embodiment, the outflow of gas from the end surfaces of the cathode electrode 20 and the first gas diffusion layer 24 and the end surfaces of the anode electrode 22 and the second gas diffusion layer 26 can be reliably prevented, and the reaction gas can be prevented. There is an effect that it is possible to prevent blowing through to the exit side without passing through the power generation surface and to further improve the sealing performance.

Next, FIG. 11 shows a fifth embodiment of the present invention.
In this embodiment, the first seal S1 is extended in the surface direction of the cathode electrode 20 and the first gas diffusion layer 24 so as to extend to the same area as the anode electrode 22 and the second gas diffusion layer 26, and the first seal S1 is expanded. By eliminating the space between S1 and the second seal S2, the first seal S1 and the second seal S2 are not subjected to unnecessary pressure applied to the seal portion due to expansion and contraction of the space portion during cooling. The seal S2 is in contact with each other during lamination.
Therefore, according to this embodiment, the outflow of gas from the end surfaces of the cathode electrode 20 and the first gas diffusion layer 24 and the end surfaces of the anode electrode 22 and the second gas diffusion layer 26 as in the fourth embodiment. Can be reliably prevented and the sealing performance can be improved. Further, by eliminating the space between the first seal S1 and the second seal S2, unnecessary pressure is not applied to the seal portion due to expansion and contraction of the space portion during cooling, and the anode There is an effect that the electrode 22 and the second gas diffusion layer 26 can be reliably supported by the first seal S1.

Next, FIG. 12 shows a sixth embodiment of the present invention.
In this embodiment, the size of the solid polymer electrolyte membrane 18 of the first embodiment shown in FIG. 7, the anode electrode 22 and the second gas diffusion layer 26 are made the same size.
Although it is difficult to make such a configuration by positioning both of the same size, after the solid polymer electrolyte membrane 18 is integrated with the anode electrode 22 and the second gas diffusion layer 26 in the manufacturing process, the end thereof is integrated. By cutting the part flush with each other, even if the position is slightly shifted, it is possible to manufacture the parts with the same position, which is advantageous in manufacturing. Further, since the solid polymer electrolyte membrane 18, the anode electrode 22, and the second gas diffusion layer 26 can be accurately positioned as described above, the fuel cell can be reduced in size.

Next, FIG. 13 shows a seventh embodiment of the present invention.
In this embodiment, the anode electrode 22 is made the same size as the cathode electrode 20 in the second embodiment shown in FIG. Thereby, since the expensive catalyst which does not contribute to reaction can be reduced, manufacturing cost can be reduced.
In this embodiment, the adhesive 50 is disposed on the portion of the anode electrode 22 that has been reduced, and the solid polymer electrolyte membrane 18 is adhered to the second gas diffusion layer 26 by the adhesive 50. Accordingly, the step between the portion where the anode electrode 22 is removed by the adhesive 50 and the portion where the anode electrode 22 is not removed can be eliminated, and the solid polymer electrolyte membrane 18 is prevented from bending at the step portion, and the solid polymer electrolyte membrane 18 is formed from this portion. It can prevent peeling.

Next, FIG. 14 shows an eighth embodiment of the present invention.
The fuel cell of this embodiment includes a fuel cell (electrode membrane structure) 12 and first and second separators 114 and 116 made of a thin metal plate such as stainless steel that sandwiches the fuel cell (electrode membrane structure). A fuel cell stack for a vehicle is configured. The fuel cells of the ninth to eleventh embodiments described below also include a metal separator.

In the figure, a fuel cell 12 includes a cathode electrode 20 and an anode electrode 22 with a solid polymer electrolyte membrane 18 interposed therebetween. The cathode electrode 20 and the anode electrode 22 have a first gas diffusion layer 24 and a second gas diffusion layer 26 made of porous carbon cloth or porous carbon paper, which are porous layers, as in the above-described embodiment. It is arranged. Here, a perfluorosulfonic acid polymer is used as the solid polymer electrolyte membrane 18. The cathode electrode 20 and the anode electrode 22 are catalysts mainly composed of Pt.
The solid polymer electrolyte membrane 18 is formed in the same size as the anode electrode 22 and the second gas diffusion layer 26, and the cathode electrode 20 and the first gas diffusion layer 24 are more than the anode electrode 22 and the second gas diffusion layer 26. The surface area is small.

The first separator 114 is arranged outside the first gas diffusion layer 24 of the fuel battery cell 12 and the second separator 116 is arranged outside the second gas diffusion layer 26 thus configured. Here, a bridge portion (separator) 151 for introducing a reaction gas is formed in the first separator 114, and the bridge portion 151 has a first seal S11 on the inner peripheral side and a second seal on the outer peripheral side. S12 is integrally formed. Here, the first seal S <b> 11 and the second seal S <b> 12 are integrally formed with a common base portion 152.
In addition, although the said bridge | bridging part 151 is described apart from the 1st separator 114 on the illustrated city, both are united. The first seal portion S11 is in close contact with the anode electrode 22 and the second gas diffusion layer 26 via the solid polymer electrolyte membrane 18, and the second seal S12 is in close contact with the second separator 116.

  Therefore, also in this embodiment, since the periphery of the anode electrode 22 and the second gas diffusion layer 26 can be reliably sealed by the first seal S11 and the second seal S12, the first seal S11, the second seal S12, The two seals S12 can function independently of each other. Therefore, as compared with a case where sealing is performed by pressing each other with the O-rings facing each other, there is no longer any seal breakage due to positional deviation, and sealing can be performed reliably.

The first seal S11 does not apply a force that causes the solid polymer electrolyte membrane 18 to be kinked, and the second seal S12 does not contact the fuel cell 12. Therefore, the force in the peeling direction does not act on the solid polymer electrolyte membrane 18. Further, since it is not necessary to match the arrangement positions of the first seal S11 and the second seal S12, the dimensional accuracy management is facilitated, the work can be easily performed, and the cost can be reduced.
Furthermore, in this embodiment, since both separators 114 and 116 are formed of metal, they can be easily formed by press molding, and the manufacturing cost can be reduced. Further, since the first seal S11 and the second seal S12 are integrally formed on the same side, it can be easily manufactured in that respect, and the number of manufacturing steps can be reduced.

Next, FIG. 15 shows a ninth embodiment of the present invention. In this embodiment, the same components as those in the above embodiment are denoted by the same reference numerals and description thereof is omitted (the same applies to the following embodiments).
In this embodiment, the second seal S12 in the eighth embodiment is separated from the first seal S11 and attached to the second separator 116 side, and the second seal S12 is attached to the bridge portion 151 of the first separator 114. It is closely attached to.
Therefore, according to this embodiment, in addition to the basic effects of the above-described embodiment, each of the first seal S11 and the second seal S12 can be molded from different materials, and the degree of freedom in design can be increased.

Next, FIG. 16 shows a reference example.
In this reference example, the first seal S11 and the second seal S12 are provided on the outer periphery of the anode electrode 22 and the second gas diffusion layer 26, the cathode electrode 20 and the first gas diffusion layer 24, and the inner side and the outer side. The positions are shifted in a double manner.
Specifically, the cathode electrode 20 and the first gas diffusion layer 24 in the eighth embodiment are formed in the same size as the anode electrode 22 and the second gas diffusion layer 26, and the first gas diffusion layer 24 and the first gas diffusion layer 24 are The solid polymer electrolyte membrane 18 is formed larger than the two-gas diffusion layer 26. A solid polymer electrolyte membrane 18 sandwiched between the cathode electrode 20 and the first gas diffusion layer 24, the anode electrode 22 and the second gas diffusion layer 26 is disposed on the second separator 116. And the 1st seal | sticker S11 of the inner peripheral side formed in the bridge part 151 and the 2nd seal | sticker S12 of the outer peripheral side are integrally molded by the base part 152 by the same magnitude | size, and 1st seal | sticker S11 is a solid polymer. The second seal S12 is in close contact with the second separator 116 and is in close contact with the electrolyte membrane 18.
According to this reference example, in addition to the basic effect of the eighth embodiment, the manufacturing cost can be reduced because the first gas diffusion layer 24 and the second gas diffusion layer 26 are small. In addition, a double seal can be provided for the reaction gas inside the first seal, and the safety against leakage of the reaction gas is improved.

Next, FIG. 17 shows another reference example.
In this reference example, the cathode electrode 20 and the first gas diffusion layer 24, the anode electrode 22 and the second gas diffusion layer 26, and the solid polymer electrolyte membrane 18 are formed in the same size. A groove 153 is formed in the vicinity of the periphery of the second gas diffusion layer 26 so that the solid polymer electrolyte membrane 18 is exposed. That is, the second gas diffusion layer 26 is formed with a groove 153 that exposes the solid polymer electrolyte membrane 18 leaving an outer peripheral portion. The bridge portion 151 is provided with an inner first seal S11 and an outer second seal S12 which are integrally formed through the base portion 152. The first seal S11 is inserted into the groove 153. It is in close contact with the solid polymer electrolyte membrane 18. The second seal S12 is in close contact with the second separator 116.
According to this reference example, since the front surface of the solid polymer electrolyte membrane 18 can be pressed from both sides, the solid polymer electrolyte membrane 18 expands and contracts even if the water content of the solid polymer electrolyte membrane 18 changes. It is possible to prevent cracks from entering.

Next, FIG. 18 shows a leak test apparatus. In the test using the leak test apparatus, the first separator 14 and the second separator 16 are fastened with bolts with the fuel cell 12 sandwiched therebetween, and helium gas is reacted from the helium cylinder HB to the center of the first separator 14. The gas was supplied to the gas flow path, and the leak amount of helium from the seal portion to the outside was confirmed by the flow meter F. The test conditions were a fastening load of 1 N / mm, a measurement atmosphere temperature of 20 to 24 ° C., and a gas pressure of 200 kPa.
The samples used have a structure in which the solid polymer electrolyte membrane 18 is sandwiched using the first seal S1 and the second seal S2, Sample 1 (the structure of the first embodiment shown in FIGS. 1 to 7), Sample 2 (Structure of the second embodiment shown in FIG. 8), Sample 3 (structure of the third embodiment shown in FIG. 9), and Sample 4 (structure of the fourth embodiment shown in FIG. 10) were used. FIG. 18 shows a state in which the test of sample 2 is being performed. In Samples 1 to 4, a stainless steel separator was used for the convenience of the experiment.
The leak test was conducted at the initial stage of the test, at a cooling / heating cycle (−40 ° C./1 hr to 90 ° C./1 hr), and at high temperature heat resistance (90 ° C.). The results are shown in Table 1.

From the test results, samples 1 to 4 did not leak in the initial test, the cooling cycle, and the high temperature heat resistance.
Therefore, it is advantageous in terms of production technology in that the allowable deviation range between the first seal S1 and the second seal S2 can be increased, and the allowable value for the alignment of the upper and lower seals can be increased.

In addition, this invention is not restricted to the said embodiment, For example, as shown in FIG. 19, it is good also as a structure which sets 1st seal | sticker S1 and 2nd seal | sticker S2 in the groove part 6. As shown in FIG. By comprising in this way, positioning of 1st seal | sticker S1 and 2nd seal | sticker S2 can be performed easily, and a seal | sticker cross-sectional area can be taken large. Various modes such as attaching the first seal S1 to the first separator 14 in advance or attaching the second seal S2 to either the first separator 14 or the second separator 16 can be adopted. is there.
The inlet side fuel gas communication hole 36a, the inlet side oxidant gas communication hole 38a, the inlet side cooling medium communication hole 40a, the outlet side cooling medium communication hole 40b, the outlet side fuel gas communication hole 36b, and the outlet side oxidant gas communication hole. It is possible to eliminate the groove of each seal S in the groove portion 30 around 38b.
A thermosetting liquid seal may be used as each seal S, first seal S1, and second seal S2.

It is a disassembled perspective view of 1st Embodiment of this invention. It is AA sectional drawing of FIG. It is a B arrow directional view of FIG. 1 of the 1st separator of embodiment of this invention. It is C arrow line view of FIG. 1 of the 2nd separator of embodiment of this invention. It is the D arrow line view of Drawing 2 of the 2nd separator of an embodiment of this invention. It is a top view of the fuel cell of a 1st embodiment of this invention. It is a principal part schematic sectional drawing of FIG. 2 of 1st Embodiment of this invention. It is sectional drawing equivalent to FIG. 7 of 2nd Embodiment of this invention. It is sectional drawing equivalent to FIG. 7 of 3rd Embodiment of this invention. It is sectional drawing equivalent to FIG. 7 of 4th Embodiment of this invention. It is sectional drawing equivalent to FIG. 7 of 5th Embodiment of this invention. It is sectional drawing equivalent to FIG. 7 of 6th Embodiment of this invention. It is sectional drawing equivalent to FIG. 7 of 7th Embodiment of this invention. It is sectional drawing equivalent to FIG. 7 of 8th Embodiment of this invention. It is sectional drawing equivalent to FIG. 7 of 9th Embodiment of this invention. It is sectional drawing equivalent to FIG. 7 of a reference example. It is sectional drawing equivalent to FIG. 7 of another reference example. It is explanatory drawing of the leak test apparatus of this invention. It is sectional drawing corresponded in FIG. 7 of other Embodiment of this invention. It is sectional drawing of a prior art.

Explanation of symbols

12 Fuel cell (electrode membrane structure)
14, 114 First separator 16, 116 Second separator 18 Solid polymer electrolyte membrane 20 Cathode electrode 22 Anode electrode 24 First gas diffusion layer 26 Second gas diffusion layer S1, S11 Seal (first seal)
S2, S12 Seal (second seal)
153 groove

Claims (11)

  In a fuel cell constructed by sandwiching an electrode membrane structure composed of a solid polymer electrolyte membrane and anode-side diffusion electrodes and cathode-side diffusion electrodes on both sides thereof with a pair of separators, the anode-side diffusion electrode and cathode side An electrode film structure is formed by disposing a diffusion electrode so that one of the surfaces is within the other surface, and an outer peripheral portion of the diffusion electrode having a large surface area among the anode-side diffusion electrode and the cathode-side diffusion electrode; A first seal is provided so as to surround a diffusion electrode having a small surface area between one separator and a second seal so as to surround the diffusion electrode having a large surface area between the one separator and the other separator. A fuel cell provided with a seal.   2. The fuel cell according to claim 1, wherein the solid polymer electrolyte membrane is formed smaller than the diffusion electrode having the large surface area.   2. The fuel cell according to claim 1, wherein at least the first seal or the second seal is in close contact with one end face of the anode side diffusion electrode and the cathode side diffusion electrode.   2. The fuel cell according to claim 1, wherein the first seal is in close contact with an end face of the diffusion electrode having the small surface area and further extends to the same area as the diffusion electrode having the large surface area.   The fuel cell according to claim 4, wherein the second seal is in close contact with both end faces of the first seal and the diffusion electrode having the large surface area.   The fuel cell according to claim 1, wherein the solid polymer electrolyte membrane and the diffusion electrode having the large surface area are the same in size.   2. The fuel cell according to claim 1, wherein the size of the catalyst portion of the diffusion electrode having the large surface area is the same as the size of the catalyst portion of the diffusion electrode having the small surface area.   The fuel cell according to claim 1, wherein the separator is made of dense carbon.   The fuel cell according to claim 1, wherein the separator is made of a thin metal plate.   The fuel cell according to claim 9, wherein the first seal and the second seal are integrally formed with a separator.   The fuel cell according to claim 10, wherein the first seal and the second seal are provided in different separators.

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