JP2004103296A - Solid polymer type fuel cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a solid polymer type fuel cell having excellent reliability by securing sealing capability between a current collection plate, and adjacent conductive separator plate and insulation plate, and by using the current collection plate capable of preventing corrosion of a manifold hole in a long-time operation. <P>SOLUTION: The current collection plate has a thin part around the manifold hole; a ring-like sealing member having a cross-sectionally U-shaped peripheral part holding the thin part from both its front and rear surfaces is mounted in the manifold hole of the current collection plate; and the current collection plate is prevented from contacting an oxidizer gas, a fuel gas or cooling water by the sealing member. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a fuel cell using a solid polymer electrolyte used for a portable power supply, a power supply for an electric vehicle, a home cogeneration system, and the like.
[0002]
[Prior art]
A fuel cell using a solid polymer electrolyte generates electricity and heat simultaneously by electrochemically reacting a fuel gas containing hydrogen and an oxidizing gas containing oxygen such as air. This fuel cell includes a polymer electrolyte membrane for selectively transporting hydrogen ions, and a pair of electrodes formed on both sides of the polymer electrolyte membrane. The electrode is usually composed mainly of carbon powder carrying a platinum-based metal catalyst, a catalyst layer formed on the polymer electrolyte membrane, and formed on the outer surface of the catalyst layer, and has air permeability and electronic conductivity. And a gas diffusion layer also having
[0003]
In order to prevent fuel gas and oxidant gas supplied to the electrode from leaking out and mixing of the two types of reaction gases with each other, a gas seal material or gasket is placed around the electrode with a polymer electrolyte membrane interposed. Be placed. This gas seal material or gasket is integrated with an electrode and a polymer electrolyte membrane in advance, and this is called an MEA (electrolyte membrane / electrode assembly).
[0004]
A conductive separator plate is disposed outside the MEA to mechanically secure it and electrically connect adjacent MEAs to each other in series. A gas passage for supplying a reaction gas to the electrode surface and carrying away generated water and surplus gas is formed in a portion of the separator plate that comes into contact with the MEA. Although the gas flow path can be provided separately from the separator plate, a method in which a groove is provided on the surface of the separator plate to form a gas flow path is generally used.
[0005]
By alternately stacking these MEAs and separator plates, 10 to 200 unit cells each composed of MEAs and separator plates are stacked, and the obtained stacked body is sandwiched between end plates via a current collector plate and an insulating plate, and fastened. The structure of a general stacked battery is fixed from both ends with rods.
[0006]
As described above, in order to take out the power generated by the stacked battery to the outside, the current collectors are arranged outside the separator plates at both ends of the stacked body in which the unit cells are stacked. Usually, the current collector plate is manufactured by processing a brass or stainless steel plate into a predetermined shape and then applying a thin gold plating in order to reduce the loss of generated power due to unnecessary contact resistance. Here, if the gold plating is made thicker than necessary, the cost is increased.
[0007]
The current collector plate has a hole called a manifold hole for supplying and discharging fuel gas, oxidizing gas, and cooling water. In order to ensure the sealing property between the current collector plate and the adjacent insulating plate or separator plate, a seal groove for an O-ring is provided around the manifold hole, and the O-ring is filled in the groove. However, the inner surface of the manifold hole of the current collector is in direct contact with the humidified reaction gas or cooling water. Therefore, when operated for a long time, corrosion proceeds from a locally thin portion of the gold plating layer formed on the inner surface of the manifold hole of the current collector in contact with the reaction gas or the cooling water, and stainless steel or brass elutes . Further, there is a problem that the eluted metal ions are supplied to the MEA, and the battery characteristics deteriorate.
[0008]
[Problems to be solved by the invention]
SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems. In order to solve the above-mentioned problems, it is possible to secure a sealing property between a current collector plate and an adjacent conductive separator plate and an insulating plate, and to prevent corrosion of a manifold hole during a long operation. It is an object of the present invention to provide a polymer electrolyte fuel cell having excellent reliability by using an electric plate.
[0009]
[Means for Solving the Problems]
The polymer electrolyte fuel cell of the present invention comprises a plurality of conductive separator plates, and an electrolyte membrane / electrode assembly inserted between the conductive separator plates, wherein the electrolyte membrane / electrode assembly is a polymer electrolyte membrane. And a cell stack comprising a pair of electrodes sandwiching the polymer electrolyte membrane, fastening means for fastening the cell stack and a pair of current collector plates for extracting generated power, and provided on the cell stack and the current collector plate The oxidizing gas, the fuel gas and the cooling water, the inlet side manifold hole and the outlet side manifold hole of each of the cooling water, and the gas flow path provided in the conductive separator plate and connecting the inlet side manifold hole and the outlet side manifold hole; Oxidant gas including a cooling water flow path, fuel gas and cooling water supply means,
The current collector plate has a thin portion around the manifold hole, and a ring-shaped seal member having an outer peripheral portion having a U-shaped cross section that holds the thin portion from both front and back surfaces is attached to the manifold hole of the current collector plate. The current collector plate is blocked from contact with the oxidizing gas, the fuel gas, and the cooling water by the seal member.
[0010]
It is preferable that the thin portion has a convex portion at the periphery of the manifold hole on both the front and back surfaces.
The end of the holding piece in the seal member holding both the front and back surfaces of the thin portion is thick, and the thickness t of the end and the step h between the main surface of the current collector plate and the thin portion are 0. It is preferable to satisfy 2 ≦ (t−h) /h≦0.3.
The end of the holding piece in the sealing member that holds the front and back surfaces of the thin portion is thick, and the volume ratio of a portion of the end that fits in the step between the main surface of the current collector and the thin portion Is preferably 70 to 90%.
[0011]
It is preferable that the thin portion is made of a reinforcing material having higher mechanical strength than the current collector plate.
It is preferable that the seal member is made of at least one material selected from the group consisting of nitrile rubber, hydrogenated nitrile rubber, silicone rubber, fluorine rubber, ethylene propylene rubber and butyl rubber.
It is preferable that the hardness of the seal member is 40 to 70.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
The point of the present invention is to secure a sealing property between the current collector plate and an adjacent insulating plate or separator plate by attaching a ring-shaped seal member to each manifold hole of the current collector plate, and to collect the current. It has been found that a method for preventing deterioration of battery performance due to corrosion in a manifold hole portion of a plate has been found.
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0013]
FIG. 3 shows a typical configuration of a polymer electrolyte fuel cell.
This fuel cell comprises a cell stack in which conductive separator plates 1 and MEAs 2 are alternately stacked, a pair of end plates 5 having both ends sandwiched by a current collector plate 3 and an insulating plate 4, and a fastening rod 7 for fastening these. It consists of. The MEA 2 includes a polymer electrolyte membrane for selectively transporting hydrogen ions, a pair of electrodes sandwiching the electrolyte membrane, and a gasket disposed around the electrodes. The current collecting plate 3 has a terminal 9 for extracting electric power to the outside.
[0014]
The present invention is to improve a current collector plate of this type of fuel cell, and one embodiment thereof is shown in FIG.
The collector plate 3 has a fuel gas inlet-side manifold hole 10a and an outlet-side manifold hole 10b, an oxidant gas inlet-side manifold hole 11a and an outlet-side manifold hole 11b, a coolant inlet-side manifold hole 12a and a coolant-side manifold. A hole 12b is provided. A hole 14 for passing a fastening rod is provided at a corner of the current collector plate 3. Then, as shown in FIG. 2, the thickness around the manifold hole such as the fuel gas inlet side manifold hole 10a becomes thinner than the thickness of the current collector plate 3 main body, and the thin portion 3a is provided around each manifold hole. Have been. Seal members 8 are respectively mounted in manifold holes such as the fuel gas inlet side manifold hole 10a in the current collector plate 3 having such a thin portion 3a.
[0015]
As a first preferred embodiment of the current collector plate 3 with the seal member 8 mounted thereon, FIG. 2 shows a schematic longitudinal sectional view of the vicinity of the fuel gas inlet side manifold hole 10a of the current collector plate.
The seal member 8 according to the present invention has a ring shape, and its outer peripheral portion has a U-shaped cross section. On the other hand, a thin portion 3a having a reduced thickness is provided around the fuel gas inlet side manifold hole 10a. Then, the seal member 8 is mounted in the manifold hole 10a so as to cover the thin portion 3a on both front and back surfaces at the U-shaped section. In this manner, the seal members 8 are respectively mounted on the manifold holes such as the fuel gas inlet side manifold hole 10a. As described above, the seal members 8 are mounted so as to completely cover the respective manifold holes. Therefore, the current collector plate does not come into contact with the fuel gas, the oxidizing gas and the cooling water, and the corrosion of the manifold hole due to the contact with the fuel gas, the oxidizing gas and the cooling water during a long operation can be prevented.
[0016]
The end 8b of the holding piece 8a for holding both the front and back surfaces of the thin portion 3a is thick and protrudes outside the current collector plate 3. When the current collecting plate 3 is fastened in combination with the cell stack and the insulating plate 4 and the like, the end 8b of the sealing member 8 functions as a packing, so that the current collecting plate 3 and the adjacent insulating plate 4 and conductive separator plate 1 can be connected. The sealing property between them can be ensured.
[0017]
As shown in FIG. 2, the thickness t of the end portion 8b of the holding piece 8a of the sealing member 8 holding both the front and back surfaces of the thin portion 3a of the current collecting plate 3, the main surface of the current collecting plate 3 and the thin portion. It is preferable that the step h with respect to 3a satisfies 0.2 ≦ h / (th−h) ≦ 0.3. At this time, the current collector 3 with the seal member 8 attached thereto has excellent sealing properties with respect to the insulating plate 4 and the conductive separator plate 1 adjacent thereto.
It is preferable that the volume ratio of a portion of the end 8b of the seal member 8 that fits in the step between the main surface of the current collector plate 3 and the thin portion 3a is 70 to 90%. At this time, the current collector plate 3 can obtain excellent sealing properties with respect to the adjacent insulating plate 4 and conductive separator plate 1.
[0018]
As a second preferred embodiment of the current collector plate provided with the seal member, FIG. 5 shows a schematic longitudinal sectional view of the vicinity of the fuel gas inlet side manifold hole of the current collector plate.
As in FIG. 2, thin portions 13a are formed around the manifold holes such as the fuel gas inlet-side manifold holes 20a of the current collector 13 respectively. Further, a convex portion 13b is provided at the peripheral portion of each manifold hole on both the front and back surfaces of the thin portion 13a. A ring-shaped seal member 18 having an outer peripheral portion having a U-shaped cross section is mounted on the thin portion 13a of such a current collector plate 13. With such a configuration, the sealing member 18 attached to the current collector plate 13 does not come off during assembly of the fuel cell stack, and is securely fixed to the current collector plate 13. The end 18b of the holding piece 18a of the seal member 18 functions as a packing.
[0019]
In addition, the same effect as in FIG. 5 can be obtained even with the configuration as in FIG. A rounded convex portion 23b is provided at the periphery of the manifold hole such as the fuel gas inlet side manifold hole 30a on both the front and back surfaces of the thin portion 23a of the current collector plate 23. As described above, the convex portions provided on the peripheral edge portions of the manifold holes on both the front and back surfaces of the thin portion of the current collector plate ensure that the sealing member attached to the current collector plate during the assembly of the fuel cell stack does not come off, and the current collector plate is securely removed. Any shape may be used as long as the configuration is such that it is fixed to.
[0020]
FIG. 7 shows a schematic vertical sectional view of the current collector plate near the fuel gas inlet side manifold hole as a third preferred embodiment of the current collector plate provided with the seal member and the reinforcing member.
As shown in FIG. 2, instead of providing the thin portions 3a around the manifold holes such as the fuel gas inlet side manifold holes 40a as shown in FIG. 2, the current collector plate 33 has inner surfaces of the manifold holes such as the fuel gas inlet side manifold holes 40a. At the center of the current collecting plate 33 in the thickness direction, a groove 33a is provided. A disc-shaped reinforcing member 34 having higher mechanical strength than the current collector 33 is attached to the groove 33a.
[0021]
On the other hand, the sealing member 38 in which the end 38b of the holding piece 38a holding the front and back surfaces of the portion exposed from the groove 33a of the reinforcing member 34 is thick is ring-shaped, and the cross section of the outer periphery is U-shaped. It is. The seal member 38 is attached to a manifold hole such as a fuel gas inlet side manifold hole 40a so as to cover a portion of the reinforcing member 34 exposed from the groove portion 33a on both front and back surfaces at a portion having a U-shaped cross section. Is done. In this manner, the seal member 38 is fixed to the current collecting plate 33 via the reinforcing member 34 so as to cover each manifold hole.
[0022]
FIG. 8 is a schematic vertical cross-sectional view of the vicinity of a fuel gas inlet side manifold hole of a current collector plate as another third preferred embodiment in which a seal member and a reinforcing member are mounted.
A protrusion 43a is provided at the center in the thickness direction of the current collector 43 on the inner surface of the manifold hole such as the fuel gas inlet side manifold hole 50a in the current collector 43. On the other hand, the ring-shaped reinforcing member 44 having higher mechanical strength than the current collector plate has a concave portion on the outer peripheral portion. By fitting the concave portion of the reinforcing member 44 into the convex portion 43a on the inner surface of each manifold hole, the reinforcing member 44 is attached to each of the manifold holes such as the fuel gas inlet side manifold hole 50a.
[0023]
Further, a protrusion 44a is provided on an inner peripheral portion of the reinforcing member 44. On the other hand, the sealing member 48 having a thick end portion 48b of the holding piece 48a for holding both the front and back surfaces of the convex portion 44a of the reinforcing member 44 has a ring shape, and the cross section of the outer peripheral portion is U-shaped. The seal member 48 is attached to each of the manifold holes such as the fuel gas inlet-side manifold hole 50a so as to cover the convex portion 44a on both front and back surfaces at the U-shaped section. In this way, the seal member 48 is fixed to the current collector 43 via the reinforcing member 44 so as to cover each manifold hole.
[0024]
As shown in FIGS. 7 and 8, the thin portion of the current collector plate on which the seal member is mounted is formed of a reinforcing material having a higher mechanical strength than the current collector plate, so that deterioration of the thin portion during long-time operation can be prevented. Can be prevented. This is particularly effective when the thickness of the thin portion is reduced.
[0025]
It is preferable that the seal member is made of at least one material selected from the group consisting of nitrile rubber, hydrogenated nitrile rubber, silicone rubber, fluorine rubber, ethylene propylene rubber and butyl rubber. Among them, fluororubber is particularly preferred because it is excellent in heat resistance, acid resistance and water resistance.
If the hardness of the sealing member is too low, the sealing property is deteriorated, and if it is too high, the reaction force at the time of sealing becomes large, and therefore, it is preferably 40 to 70.
[0026]
【Example】
Hereinafter, embodiments of the present invention will be described with reference to FIGS.
[0027]
<< Example 1 >>
A platinum particle having an average particle size of about 30 ° was supported on an acetylene black-based carbon powder at a weight ratio of 4: 1 to obtain a catalyst powder for an electrode. An electrode paste was obtained by mixing 5 g of this catalyst powder in 15 g of water and 40 g of 10 wt% of perfluorocarbon sulfonic acid in ethyl alcohol in ethyl alcohol. .
[0028]
On the other hand, carbon paper having a thickness of 300 μm was immersed in an aqueous dispersion of polytetrafluoroethylene (PTFE) and then dried to obtain a water-repellent porous electrode substrate. An electrode paste was applied to one surface of the porous electrode substrate and dried to obtain an electrode. Next, the polymer electrolyte membrane is sandwiched between the pair of electrodes obtained above with the surface on which the electrode paste is applied inward, and this is hot-pressed at 110 ° C. for 30 minutes to obtain an electrolyte membrane-electrode assembly. 2 (MEA) was produced. As the polymer electrolyte membrane used here, perfluorocarbon sulfonic acid thinned to a thickness of 50 μm (Nafion, manufactured by DuPont) was used.
[0029]
The conductive separator plate 1 made of a 3 mm-thick isotropic graphite material and having a gas flow path formed by machining was alternately stacked with 50 cells of the MEA 2 obtained above to prepare a cell stack.
[0030]
On the other hand, the current collecting plate 3 equipped with the seal member of the present invention was manufactured as follows.
Using brass having a thickness of 5 mm, machining was performed in a predetermined shape as shown in FIGS. At this time, fuel gas inlet-side manifold holes 10a and outlet-side manifold holes 10b on both surfaces of the current collector plate, oxidant gas inlet-side manifold holes 11a and outlet-side manifold holes 11b, and coolant inlet-side manifold holes 12a and outlets. The thickness around the side manifold hole 12b was reduced by 1 mm to provide a thin portion 3a having a thickness of 3 mm. Thereafter, the surface of the current collector plate 3 was subjected to a gold plating treatment with a thickness of 1 μm. Then, as shown in FIG. 2, ring-shaped seal members 8 having thick end portions 8b of holding pieces 8a for holding both front and rear surfaces of the thin portion 3a were mounted on each manifold hole of the current collector plate.
[0031]
The seal member 8 used here is a fluorine rubber having a hardness of 50, and was manufactured by injection molding. At this time, the thickness t of the end portion 8b of the sealing member 8 is 1.2 mm, the step h between the main surface of the current collector and the thin portion is 1.0 mm, and the value (t−h) / h is 0. .2. In addition, the volume ratio of the portion of the end 8b of the sealing member 8 that fits in the step between the main surface of the current collector 3 and the thin portion 3a is set to 80%.
[0032]
The current collecting plate 3 to which the sealing member 8 obtained above was attached was disposed at both ends of the cell laminate obtained above, and the insulating plate 4 was further disposed outside the same. The terminal 9 was connected to the current collector 3. The laminate was sandwiched between end plates 5 made of stainless steel via the current collector plate 3 and the insulating plate 4, and the laminate was fastened with a fastening rod 7 and a screw spring 6 at a pressure of 10 kgf / cm ² . A fuel cell having the structure shown in FIG. This is called battery A.
[0033]
<< Comparative Example 1 >>
Instead of the current collecting plate equipped with the seal member of Example 1, a current collecting plate equipped with a conventional O-ring was used. The current collecting plate to which the O-ring was attached was manufactured as follows.
Using the same brass as in Example 1, a predetermined current collector plate was manufactured by machining. An O-ring groove 53a was provided at a predetermined position around the manifold hole such as the fuel gas inlet side manifold hole 60a. Then, as shown in FIG. 9, O-rings 58 made of fluorine rubber and having a circular cross section were mounted in O-ring grooves 53a provided around the respective manifold holes.
A fuel cell was manufactured in the same manner as in Example 1 except that the current collector 53 provided with the O-ring 58 obtained above was used. This battery is referred to as battery B.
[0034]
The battery A of Example 1 and the battery B of Comparative Example 1 produced above were subjected to the following durability test. Humidified and heated fuel gas was supplied to one electrode at a dew point of 83 ° C., and humidified and heated air was supplied to the other electrode at a dew point of 78 ° C. Then, an endurance test was performed in an environment of 85 ° C. under the conditions of a fuel utilization rate of 80%, an oxygen utilization rate of 30%, and a current density of 0.3 A / cm ² . The result is shown in FIG.
[0035]
In the battery B of Comparative Example 1, the reduction rate of the battery voltage became large after 500 hours from the start of the test, and the performance could not be completely obtained in 2000 hours. In contrast, the battery A of Example 1 exhibited stable performance even after lapse of 5000 hours.
After the endurance test, the battery B of Comparative Example 1 was disassembled, and the current collector plate was observed. As a result, there was no gold-plated portion near the inlet-side manifold hole and the outlet-side manifold hole of the fuel gas, oxidizing gas, and cooling water, and brass was removed. Elution was confirmed. This is because the corrosion progressed selectively from a locally thin portion of the gold plating layer formed on the current collector plate due to the electrolysis of the humidification water or the cooling water during power generation. Further, the metal ions eluted by the electrolysis were taken into the fuel gas, the oxidizing gas and the humidified water, and supplied to the MEA, thereby causing deterioration of the polymer electrolyte. On the other hand, the current collector of Example 1 did not show any corrosion even after 6000 hours, confirming the effectiveness of the current collector provided with the seal member of the present invention.
[0036]
<< Example 2 >>
The current collector 33 to which the reinforcing member 34 was attached was manufactured as follows.
A current collector plate having a predetermined shape was produced by machining using brass having a thickness of 2.5 mm. As shown in FIG. 7, a groove 33a is provided at the center of the current collector 33 in the thickness direction on the inner surface of the manifold hole such as the fuel gas inlet side manifold hole 40a in the current collector 33. Then, a stainless steel reinforcing member 34 having higher mechanical strength than brass was attached to the groove 33a.
[0037]
The seal member 38 was manufactured as follows.
A predetermined sealing member 38 was produced in the same manner as in Example 1 using a fluorine rubber having a hardness of 50. At this time, the thickness t of the end portion 38b of the holding member 38a holding the front and back surfaces of the reinforcing member 34 in the seal member 38 is 1.2 mm, and the step h between the surface of the current collector plate 33 and the reinforcing member 34 is 1 0.0 mm, and the (t−h) / h value was 0.2. The volume ratio of the portion of the end 38b that fits into the step between the surface of the current collector 33 and the reinforcing member 34 is set to 80%.
The seal member 38 obtained above was mounted on the current collecting plate 33 to which the reinforcing member 34 obtained above was attached.
A fuel cell was obtained in the same manner as in Example 1, except that this current collector was used instead of the current collector of Example 1. This battery is referred to as battery C.
[0038]
<< Example 3 >>
A current collector was produced in the same manner as in Example 1, except that brass having a thickness of 2.5 mm was used. Then, the same sealing member as in Example 2 was attached to this current collector plate. A fuel cell was obtained in the same manner as in Example 1 except that this current collector was used. This battery is referred to as Battery D.
[0039]
An endurance test was performed on the battery C of Example 2 and the battery D of Example 3 under the same conditions as in Example 1. After 6000 hours, Battery C and Battery D were each disassembled, and the current collector plate was examined. As a result, cracks were found at the base of the thin portion of the current collector plate of the battery D of Example 3. This is considered to be because the thickness of the current collector plate of Example 3 was smaller than that of Example 1, and cracks occurred at the root portion having the lowest strength due to long-time operation. On the other hand, in the battery C of Example 2, no crack was observed. From this, it was shown that when the thickness of the thin portion to which the seal member is attached becomes thin because the thickness of the current collector plate is thin, it is effective to configure the thin portion with a reinforcing material.
[0040]
【The invention's effect】
INDUSTRIAL APPLICABILITY As described above, according to the present invention, a current collector plate that can ensure the sealing performance between a current collector plate and an adjacent conductive separator plate and insulating plate, and can prevent corrosion of a manifold hole during long-time operation By using, a polymer electrolyte fuel cell with excellent reliability can be provided.
[Brief description of the drawings]
FIG. 1 is a front view showing a configuration of a current collector plate of the present invention.
FIG. 2 is a schematic vertical sectional view showing the vicinity of a fuel gas inlet-side manifold hole in a current collector provided with a seal member of the present invention.
FIG. 3 is a front view showing a configuration of a fuel cell using the current collector plate of the present invention.
FIG. 4 is a diagram showing the relationship between the cell voltage and the elapsed time of the batteries of Example 1 and Comparative Example 1 in an endurance test.
FIG. 5 is a schematic vertical cross-sectional view showing the vicinity of a fuel gas inlet-side manifold hole of a current collector plate provided with a seal member on a current collector plate having a convex portion formed on the periphery of a manifold hole on both front and rear surfaces of a thin portion according to the present invention. is there.
FIG. 6 is a schematic vertical cross-sectional view of a fuel gas inlet-side manifold hole near a fuel gas inlet plate in which a sealing member is mounted on a current collector plate provided with protrusions on the front and rear surfaces of the manifold holes on both sides of another thin portion of the present invention; FIG.
FIG. 7 is a schematic longitudinal sectional view of the vicinity of a fuel gas inlet side manifold hole in a current collector plate provided with a reinforcing member and a seal member of the present invention.
FIG. 8 is a schematic longitudinal sectional view of the vicinity of a fuel gas inlet side manifold hole in a current collector plate provided with another reinforcing member and a seal member according to the present invention.
FIG. 9 is a schematic vertical cross-sectional view of the vicinity of a fuel gas inlet side manifold hole in a current collector plate equipped with a conventional O-ring.
[Explanation of symbols]
1 conductive separator plate 2 MEA
3, 13, 23, 33, 43, 53 Current collector plates 3a, 13a, 23a Thin portion 4 Insulating plate 5 End plate 6 Screw spring 7 Fastening rods 8, 18, 28, 38, 48 Seal members 8a, 18a, 28a, 38a, 48a Holding pieces 8b, 18b, 28b, 38b, 48b End 9 Terminals 10a, 20a, 30a, 40a, 50a, 60a Fuel gas inlet side manifold hole 10b Fuel gas outlet side manifold hole 11a Oxidant gas Inlet-side manifold hole 11b Oxidant gas outlet-side manifold hole 12a Cooling water inlet-side manifold hole 12b Cooling water outlet-side manifold hole 13b, 23b Convex portion 14 Fastening rod holes 33a, 53a Grooves 34, 44 Reinforcement 43a, 44a convex

Claims (7)

A plurality of conductive separator plates, and an electrolyte membrane / electrode assembly inserted between the conductive separator plates, wherein the electrolyte membrane / electrode assembly is a polymer electrolyte membrane and a pair of electrodes sandwiching the polymer electrolyte membrane , A fastening means for fastening a pair of current collector plates for taking out the cell stack and the generated power, and oxidizing gas, fuel gas and cooling water provided in the cell stack and the current collector plate Oxidant gas, fuel gas including a gas flow path and a cooling water flow path provided at each of the inlet side manifold hole and the outlet side manifold hole, and provided on the conductive separator plate and connecting the inlet side manifold hole and the outlet side manifold hole, fuel gas And cooling water supply means,
The current collector plate has a thin portion around the manifold hole, and a ring-shaped seal member having an outer peripheral portion having a U-shaped cross section that holds the thin portion from both front and back surfaces is attached to the manifold hole of the current collector plate. A polymer electrolyte fuel cell in which the current collector plate is blocked from contact with the oxidizing gas, the fuel gas, and the cooling water by the seal member. The polymer electrolyte fuel cell according to claim 1, wherein the thin portion has a convex portion at the periphery of the manifold hole on both front and back surfaces. The end of the holding piece in the sealing member holding both the front and back surfaces of the thin portion is thick, and the thickness t of the end and the step h between the main surface of the current collector plate and the thin portion are 0. 3. The polymer electrolyte fuel cell according to claim 1, wherein 2 ≦ (t−h) /h≦0.3 is satisfied. The end of the holding piece in the sealing member holding the front and back surfaces of the thin portion is thick, and the volume ratio of a portion of the end that fits in the step between the main surface of the current collector and the thin portion The polymer electrolyte fuel cell according to any one of claims 1 to 3, wherein the content is 70 to 90%. The polymer electrolyte fuel cell according to any one of claims 1 to 4, wherein the thin portion is made of a reinforcing material having higher mechanical strength than the current collector plate. The solid height according to claim 1, wherein the sealing member is made of at least one material selected from the group consisting of nitrile rubber, hydrogenated nitrile rubber, silicone rubber, fluorine rubber, ethylene propylene rubber and butyl rubber. Molecular fuel cell. 5. The polymer electrolyte fuel cell according to claim 1, wherein the seal member has a hardness of 40 to 70.

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