JP4274892B2 - Polymer electrolyte fuel cell - Google Patents

Description

  The present invention relates to a polymer electrolyte fuel cell.

  A polymer electrolyte fuel cell is composed of a proton conductive polymer electrolyte thin film, anode and cathode reaction electrodes, gasket-like sealing material disposed at the periphery of each reaction electrode, carbon or metal It comprises a bipolar plate and a cooling plate for cooling the bipolar plate.

  The electrode catalyst layer that causes the electrochemical reaction of the battery uses a mixture of carbon powder supporting a noble metal catalyst and the same material as the proton conductive polymer electrolyte thin film described above. If necessary, a fluorocarbon compound-based water repellent material is added thereto. The reaction electrode has a configuration in which the electrode catalyst layer and the gas diffusion layer are joined.

  The constituent materials of the anode and the cathode can be the same when using pure hydrogen as a fuel. When hydrogen-rich gas obtained by reforming hydrocarbon fuel is used as fuel, in order to suppress poisoning of noble metal catalyst by carbon monoxide contained in the reformed gas, only the anode side is resistant to CO poisoning such as ruthenium. It has also been proposed to add materials.

As the polymer electrolyte, a fluorocarbon polymer having a pendant sulfone group at the end of the side chain can be used. This electrolyte has proton conductivity in a state containing moisture. Therefore, in order to operate the battery, it is necessary to always keep the polymer electrolyte in a state containing moisture. The polymer electrolyte in a moisture-containing state exhibits strong acidity due to H ⁺ dissociated from the terminal sulfone group. For this reason, acid resistance is required for the material of the portion in direct contact with the electrolyte. In addition, since the same material as the electrolyte is mixed in the reaction electrode, acid resistance is also required for the material used for the portion in direct contact with the reaction electrode. For these reasons, fluorocarbon polymer materials with strong acid resistance have been used for sealing materials such as gaskets that are in direct contact with the electrolyte.

  On the other hand, a gasket-like sealing material is disposed on the peripheral edge of the reaction electrode, and is sandwiched between a pair of bipolar plates so that the fuel gas supplied to each cathode and anode reaction electrode is not released to the outside. Conventionally, since a hard gasket such as a fluorine-based resin has been previously installed on the peripheral edge of the electrode and then sandwiched between bipolar plates, it has been necessary to adjust the thickness of the electrode and gasket in advance with high accuracy.

  However, if the gasket has rubber-like elasticity, strict dimensional accuracy is not required, and it is possible to fulfill the function as a gasket with a certain degree of thickness adjustment. Thus, it is desirable that the gasket has a rubber-like elasticity as well as acid resistance. For this reason, acid resistance is inferior to that of fluororesin, but elastic ethylene-propylene-diene rubber (EPDM) or the like may be used as a gasket material.

  In addition, since the bipolar plate is in direct contact with the electrode, acid resistance is required, and at the same time, the bipolar plate is required to be gas tight and have high electrical conductivity. In addition, when air is used as the oxidant, it is necessary to efficiently remove water or water vapor generated by increasing the flow rate of air supplied to the cathode. Therefore, a complicated flow channel structure generally called a serpentine type as shown in FIG. 1 has been used for the gas flow channel structure of the bipolar plate. The material of the bipolar plate is a dense carbon plate that is gas tight, a carbon plate impregnated with a resin, or a carbon-based material such as glassy carbon, and this is subjected to cutting and a gas flow groove is provided to form a bipolar plate. Further, if necessary, a corrosion-resistant alloy plate is cut and plated with a noble metal and used as a bipolar plate.

In addition, if necessary, the carbon-based material or the corrosion-resistant metal material is used only for the part that needs electrical conductivity in contact with the electrode, and the resin is used for a part that does not require electrical conductivity, such as a peripheral manifold part. There have also been attempts to use bipolar plates for composite materials.
It has also been proposed to mix carbon powder or metal powder with a resin and form it by pressing or injection molding.

  However, when a fluorocarbon material is used for a sealing material such as a gasket, there is a problem that the cost is high. In addition, fluorocarbon materials are generally very hard as a resin, and a gasket must be tightened with a very large load in order to seal gas or cooling water. For this reason, attempts have been made to use porous fluorocarbon-based materials and paste-type fluorocarbon materials applied to bipolar plates and the like, and attempts have been made to use them in a dry or semi-dried state. However, porous fluorocarbon-based materials are still used. Expensive. In addition, there is a problem that a sufficient sealing effect cannot be obtained unless a load is applied until the porosity is lost.

  On the other hand, even if a paste-like fluorocarbon material is used for the sealing material, the material itself is still expensive, and it is still hard in the dried state, so that it is difficult to adjust the thickness at the time of application. In addition, rubber-like materials such as EPDM are not suitable for long-time use because they do not have acid resistance as high as that of fluorine-based resins. Furthermore, since general EPDM has thermoplasticity, when it is used at a battery operating temperature of about 80 ° C., it is accompanied by deformation over time, and in some cases, the gas flow path is blocked to reduce the amount of fuel supplied. There was a problem of making it happen.

  Furthermore, regarding the material of the bipolar plate, when a gas tight and dense carbon plate or glassy carbon is used, the gas flow path or the like must be cut. This is not suitable from the viewpoint of mass production and cost reduction. Further, when a carbon plate impregnated with resin is used, since the resin has little elasticity, if the resin is impregnated after processing such as a gas flow path, the carbon plate is warped. Therefore, after impregnating the resin in advance, it is necessary to process the gas flow path and the like, and post-processing such as cutting is necessary. In addition, when phenol resin or silicon resin is used as an impregnation material, there is a problem in acid resistance. Also, when using a corrosion-resistant alloy, a noble metal plating plate, or the like, cutting is necessary to use the serpentine type flow path structure.

  Furthermore, even when carbon powder or metal powder and a resin are mixed and molded by pressing or injection molding, the resin itself needs to have acid resistance. In this regard, when a hard material such as a fluorine-based resin is used, the fluidity is low and molding is difficult. Also, if a resin with poor fluidity is used, it is necessary to reduce the resin content. Therefore, after molding, post-treatment such as re-impregnating the resin with a part that requires gas tightness is necessary, and it is configured accordingly. There was a problem that became complicated.

In order to solve the above problems, the present invention sandwiches a pair of reaction electrodes sandwiching a solid polymer electrolyte membrane with a pair of bipolar plates for supplying and discharging fuel gas and oxidant gas to and from the reaction electrodes, A polymer electrolyte fuel cell in which a cooling jig is attached to a bipolar plate,
Said bipolar plate, and a carbon material or a metal material, the Lee isobutylene is constituted by a material shown in the main chain skeleton is (of 1), R ₁ and R ₂ is a non-functional group terminated, Z Is a functional group formed by combining functional groups X and Y, both functional groups X and Y are allyl groups, and the repeat number m of isobutylene is an integer satisfying 56 ≦ m ≦ 72. A polymer electrolyte fuel cell having a polymerization degree i of an integer of 8000 or more is provided.

The repeating number m of isobutylene materials described in the Lee isobutylene as a main chain skeleton (Formula 1) is preferably a mean 64.

Moreover, sealing material composed of a material shown in the Lee isobutylene as a main chain skeleton (of 1), after applying the solution, sealing portions containing at least a reactive oligomer shown in (Formula 2), wherein It is formed by curing by copolymerization of a reactive oligomer.

Fuel cell according to the present invention, by using the materials described in the Lee isobutylene as a main chain skeleton (Formula 1), it is possible to realize a polymer electrolyte fuel cell having high reliability.

Polymer electrolyte fuel cell of the present invention, as a bipolar plate, wherein the carbon material or a metal material, the Lee isobutylene was and the point of using a bipolar plate that is made of a material shown in the main chain skeleton (of 1) Have Moreover, and sealing material of a component reactive electrodes, sealing materials of the cooling water or the material that seals the internal humidification of the water or gas, the material described in the Lee isobutylene as a main chain skeleton (of 1) Thus, an inexpensive and acid-resistant sealing material can be made available.

Manufacturing method of this time, a solution containing at least a reactive oligomer shown in (Formula 2) was applied to the seal portion, by curing by copolymerization of the reactive oligomer, it can be manufactured at low cost.

Material shown in the Lee isobutylene as a main chain skeleton (of 1), superior in acid resistance, is inexpensive, and has elasticity, since it has a heat resistance, a fluorine-based resin as the sealing material of the gasket and the cooling water It is superior to resin based on resin and EPDM.

In the case of using a carbon plate impregnated with material described in the Lee isobutylene as a main chain skeleton (Formula 1) as a bipolar plate, since the resin has elasticity, no denseness to the carbon plate gas passage such It is possible to impregnate the resin after the above processing. Since the non-dense carbon plate before impregnation with the resin is softer and has better processability than after the resin impregnation, the processing can be greatly facilitated.

Further, by mixing a polymer material showing a carbon powder or metal powder and Lee isobutylene in a main chain skeleton (Formula 1), it may be molded by pressing or injection molding, during molding the resin has elasticity Can improve fluidity. Even if the amount of resin added is increased, the flowability at the time of molding is good, so steps such as post-processing after molding can be omitted.

Also, of the bipolar plate, using carbon or metal only to a portion that requires electrical conductivity, main chain and b isobutylene in the peripheral portion and the sealing portion to form a complex shape, such as no electrically conductive required manifold In the case of using the material shown in (Chemical Formula 1), since it has rubber-like flexibility, sealing is easy. And a carbon or metal material used in the necessary portion of the electrically conductive material of the heat indicated by Louis isobutylene electrical conductivity has been used in a portion not required as a main chain skeleton (of 1) Even if the expansion coefficients are different, since they have rubber-like flexibility, there is no risk of the bipolar plate itself being damaged due to the difference in the thermal expansion coefficient when the battery is raised or lowered.

  In the above description, the material represented by (Chemical Formula 1) is obtained by cross-linking at the terminal functional group portion, with 1 unit of the terminal functional groups X and Y added to an isobutylene oligomer having a repeating number of m. When allyl group, acryloyl group, methacryloyl group, isocyanate group, and epoxy group are used as X and Y, these functional groups are polyfunctional groups. A cross-linked network structure is obtained.

At this time, the physical properties of the polymer, (Formula 1) in the material shown in, receives a repeating number m of Isobuchire down, the overall degree of polymerization i, greatly affected by the type of terminal functional groups. The inventor of the examination results, when using this material in the sealant in a polymer electrolyte fuel cell, the number of repetitions m of Isobuchire emissions are 56 ≦ m ≦ 72, it is desirable average is 64, Moreover, it discovered that it was desirable for the polymerization degree i to be 8000 or more.

The present invention will be described below with reference to the drawings.
《Reference example》
A catalyst comprising 25% by weight of platinum particles having an average particle size of about 30 supported on acetylene black carbon powder was used as a catalyst for the reaction electrode. A dispersion solution in which perfluorocarbon sulfonic acid powder represented by (Chemical Formula 3) was dispersed in ethyl alcohol was mixed with a solution in which the catalyst powder was dispersed in isopropanol to obtain a paste. Using this paste as a raw material, an electrode catalyst layer was formed on one surface of a carbon nonwoven fabric having a thickness of 250 μm using a screen printing method. Amount of platinum contained in the reaction electrode after forming the 0.5 mg / cm ^2, the amount of perfluorocarbon sulfonic acid was adjusted to be 1.2 mg / cm ^2.

These electrodes have the same configuration for both the positive electrode and the negative electrode, and as shown in FIG. 2, the printed catalyst layer is on the electrolyte membrane side on both sides of the central portion of the proton conductive polymer electrolyte membrane having a slightly larger area than the electrode. The electrode / electrolyte assembly (MEA) was formed by bonding by hot pressing so as to be in contact with each other. Here, as the proton conductive polymer electrolyte, a perfluorocarbon sulfonic acid shown in (Chemical Formula 4) having a thickness of 25 μm was used.

  Next, as shown in FIG. 3, a gasket-shaped seal was prepared by providing holes for reaction electrodes and gas manifolds and molding them into a plate shape. The electrolyte membrane part around the MEA electrode was sandwiched between two gasket seals so that the reaction electrode part of the MEA fits into the reaction electrode hole in the center. Further, a polymer electrolyte fuel cell is constructed by sandwiching an MEA and a gasket seal between two bipolar plates in such a manner that the gas flow paths of the bipolar plate made of the non-porous carbon plate having the shape shown in FIG. 1 face each other. did.

A heater plate, current collector plate, insulation plate, and end plate with gas manifold holes are attached to both outer sides of this polymer electrolyte fuel cell, and bolts, springs, and nuts are installed between the outermost end plates. A single cell of a polymer electrolyte fuel cell was constructed by tightening at a pressure of 20 kg / cm ² with respect to the electrode area.

Or plate-like molded gasket-like seal, the ones having a thickness of 250μm was a material shown in the Lee isobutylene as a main chain skeleton (Formula 1), it was used by punching the necessary holes.

  The polymer electrolyte fuel cell produced in this way is maintained at 75 ° C., humidified and heated to a dew point of 73 ° C. on one electrode side, and a dew point of 68 ° C. on the other electrode side. Then, humidified and heated air was supplied. As a result, a battery open voltage of 0.98 V was obtained at no load when no current was output to the outside.

Further, gas leakage from the gasket-like seal portion (peripheral portion) of this battery was measured, but there was no gas leakage. Further, when this battery was subjected to a continuous power generation test under the conditions of a fuel utilization rate of 80%, an oxygen utilization rate of 40%, and a current density of 0.3 A / cm ² , a battery voltage of 0.7 V or more was maintained for 5000 hours or more. .

Used in the present reference example, materials described in the isobutylene as a main chain skeleton (of 1), the repeating number m of 56 ≦ m ≦ 72, average 64 isobutylene in the configuration shown in (Formula 2), Polymerization was performed by irradiating an electron beam with an acceleration voltage of 200 keV and an irradiation dose of 10 Mrad on an allyl group having both functional groups X and Y. The degree of polymerization was about 10,000.

  When the repeating number m of isobutylene was made smaller than 56, the polymer after polymerization was stiff, and a larger tightening pressure was required to eliminate hydrogen gas leakage from the gasket part of the assembled battery. Further, when m was larger than 72, it was too soft, and hydrogen gas leak was detected from the gasket-like seal portion when about 2000 hours passed after the battery test was started.

  In addition, as a result of studying the influence of the degree of polymerization by controlling the amount of electron beam irradiation, if the degree of polymerization is less than 8000, the polymer is too soft, and the hydrogen gas from the gasket-like seal portion during the battery test described above. A leak was detected.

  Moreover, it confirmed that what was hardened | cured by the polymerization reaction suitable for each as a terminal functional group other than this as an acryloyl group, a methacryloyl group, an isocyanate group, and an epoxy group can be used similarly. At this time, when an acryloyl group or a methacryloyl group is used as a terminal functional group, the same electron beam irradiation is used. When an isocyanate group is used, a urethane bond is formed by moisture. When an epoxy group is used, a known amine such as ethyldiamine is used. It hardened | cured by heating using a system hardening | curing agent. However, at this time as well, when the functional group is an allyl group, when the number of repetitions of isobutylene in the structure represented by (Chemical Formula 2) is 56 ≦ m ≦ 72 and the degree of polymerization is 8000 or more, It was confirmed that gas leakage could be prevented for a long time.

Example 1
A catalyst comprising 25% by weight of platinum particles having an average particle size of about 30 supported on acetylene black carbon powder was used as a catalyst for the reaction electrode. A dispersion solution in which perfluorocarbon sulfonic acid powder represented by (Chemical Formula 3) was dispersed in ethyl alcohol was mixed with a solution in which the catalyst powder was dispersed in isopropanol to obtain a paste. Using this paste as a raw material, an electrode catalyst layer was formed on one surface of a carbon nonwoven fabric having a thickness of 250 μm using a screen printing method. Amount of platinum contained in the reaction electrode after forming the 0.5 mg / cm ^2, the amount of perfluorocarbon sulfonic acid was adjusted to be 1.2 mg / cm ^2.

  These electrodes have the same configuration for both the positive electrode and the negative electrode, and as shown in FIG. 2, the printed catalyst layer is on the electrolyte membrane side on both sides of the central portion of the proton conductive polymer electrolyte membrane having a slightly larger area than the electrode. The electrode / electrolyte assembly (MEA) was formed by bonding by hot pressing so as to be in contact with each other. Here, as the proton conductive polymer electrolyte, a perfluorocarbon sulfonic acid shown in (Chemical Formula 4) having a thickness of 25 μm was used.

  Two plate-like shapes are formed so that the electrode portion of the MEA fits into the square-shaped electrode hole in the center of the plate-like molded gasket provided with the electrode, cooling water, and gas manifold holes shown in FIG. The electrolyte membrane part around the MEA electrode is sandwiched between the molded gaskets, and the two gas plate-shaped bipolar plates shown in FIG. 5 are opposed to each other. A polymer electrolyte fuel cell was constructed by sandwiching a molded gasket.

In this case the bipolar plate used was the expanded graphite powder, the material shown in the isobutylene as a main chain skeleton (Formula 1) were mixed, was prepared by press molding. At this time, one surface of the bipolar plate is configured to have the gas flow path shown in FIG. 5, and a groove for cooling water flow path is formed on the opposite surface.

At this time the plate-shaped molded gasket used was a layer thickness of 100μm heat polyethylene terephthalate (PET) resin in the center, on both sides of the PET, the thickness 75μm increments Lee isobutylene main chain skeleton ( of 1 material having a structure sandwiched by sheet layers shown in), it was used by punching the necessary holes.

Incidentally, used in the present example, materials shown in the isobutylene as a main chain skeleton (Formula 1), has the structure of the same position as that used in Reference Example was constructed in the same manufacturing process.

This polymer electrolyte fuel cell was used as a unit cell, and 50 polymer electrolyte fuel cells having the same configuration were stacked in the configuration schematically shown in FIG. At this time, the cooling water passage near Gasushi - in pole tip, a material shown in the Lee isobutylene as a main chain skeleton (Formula 1). A current collector plate, insulation plate, and end plate with holes for the required gas manifold and cooling water manifold are installed on both sides of the laminated battery, and bolts, springs, and nuts are used between the outermost end plates. Then, the polymer electrolyte fuel cell stack was constructed by tightening at a pressure of 20 kg / cm ² with respect to the electrode area.

The polymer electrolyte fuel cell stack is maintained at 75 ° C. while flowing cooling water, and humidified and heated so that the dew point is 73 ° C. on the negative electrode side, and the dew point is 68 ° C. on the positive electrode side. When humidified and heated air was supplied, a battery voltage of 49 V was obtained at no load. Further, the gas leak from the gasket part (peripheral part) of this battery was measured, but no gas leak was detected. Furthermore, when this battery was subjected to a continuous power generation test under the conditions of a fuel utilization rate of 80%, an oxygen utilization rate of 40%, and a current density of 0.7 A / cm ² , while maintaining a battery voltage of 31 V or more for 5000 hours or more, Power generation was possible without deterioration of battery voltage.

Example 2
A catalyst comprising 25% by weight of platinum particles having an average particle size of about 30 supported on acetylene black carbon powder was used as a catalyst for the reaction electrode. A dispersion solution in which perfluorocarbon sulfonic acid powder represented by (Chemical Formula 3) was dispersed in ethyl alcohol was mixed with a solution in which the catalyst powder was dispersed in isopropanol to obtain a paste. Using this paste as a raw material, an electrode catalyst layer was formed on one surface of a carbon nonwoven fabric having a thickness of 250 μm using a screen printing method. Amount of platinum contained in the reaction electrode after forming the 0.5 mg / cm ^2, the amount of perfluorocarbon sulfonic acid was adjusted to be 1.2 mg / cm ^2.

  These electrodes have the same configuration for both the positive electrode and the negative electrode, and as shown in FIG. 2, the printed catalyst layer is on the electrolyte membrane side on both sides of the central portion of the proton conductive polymer electrolyte membrane having a slightly larger area than the electrode. The electrode / electrolyte assembly (MEA) was formed by bonding by hot pressing so as to be in contact with each other. Here, as the proton conductive polymer electrolyte, a perfluorocarbon sulfonic acid shown in (Chemical Formula 4) having a thickness of 25 μm was used.

  Two plate-like shapes are formed so that the electrode portion of the MEA fits into the square-shaped electrode hole in the center of the plate-like molded gasket provided with the electrode, cooling water, and gas manifold holes shown in FIG. The electrolyte membrane part around the MEA electrode is sandwiched between the molded gaskets, and the two gas plate-shaped bipolar plates shown in FIG. 5 face each other, and the MEA and the plate shape are sandwiched between the two bipolar plates. A polymer electrolyte fuel cell was constructed by sandwiching a molded gasket.

In this case the bipolar plate used is a preformed porous sheet of expanded graphite powder, the material shown in the isobutylene as a main chain skeleton (Formula 1) was impregnated, it was prepared by press molding. At this time, one surface of the bipolar plate is configured to have the gas flow path shown in FIG. 5, and a groove for cooling water flow path is formed on the opposite surface.

At this time the plate-shaped molded gasket used was a heat-resistant polyethylene terephthalate (PET) resin having a thickness of 100μm on a layer of the central portion, on both sides of the PET, the Lee isobutylene-by thickness 75μm and main chain skeleton ( of 1 in the material structure of those sandwiched by sheet layer described in), it was used by punching the necessary holes.

Incidentally, used in the present example, materials shown in the isobutylene as a main chain skeleton (Formula 1), has the structure of the same position as that used in Reference Example was constructed in the same manufacturing process.

This polymer electrolyte fuel cell was used as a unit cell, and 50 polymer electrolyte fuel cells having the same configuration were stacked in the configuration schematically shown in FIG. At this time, also the gas seal portion near the cooling water flow path, using the material described in the Lee isobutylene as a main chain skeleton (Formula 1). A current collector plate, insulation plate, and end plate with holes for the required gas manifold and cooling water manifold are installed on both sides of the laminated battery, and bolts, springs, and nuts are used between the outermost end plates. Then, the polymer electrolyte fuel cell stack was constructed by tightening at a pressure of 20 kg / cm ² with respect to the electrode area.

The polymer electrolyte fuel cell stack is maintained at 75 ° C. while flowing cooling water, and humidified and heated so that the dew point is 73 ° C. on the negative electrode side, and the dew point is 68 ° C. on the positive electrode side. When humidified and heated air was supplied, a battery voltage of 49 V was obtained at no load. Further, the gas leak from the gasket part (peripheral part) of this battery was measured, but no gas leak was detected. Furthermore, when this battery was subjected to a continuous power generation test under the conditions of a fuel utilization rate of 80%, an oxygen utilization rate of 40%, and a current density of 0.7 A / cm ² , while maintaining a battery voltage of 31 V or more for 5000 hours or more, Power generation was possible without deterioration of battery voltage.

Example 3
A catalyst comprising 25% by weight of platinum particles having an average particle size of about 30 supported on acetylene black carbon powder was used as a catalyst for the reaction electrode. A dispersion solution in which perfluorocarbon sulfonic acid powder represented by (Chemical Formula 3) was dispersed in ethyl alcohol was mixed with a solution in which the catalyst powder was dispersed in isopropanol to obtain a paste. Using this paste as a raw material, an electrode catalyst layer was formed on one surface of a carbon nonwoven fabric having a thickness of 250 μm using a screen printing method. Amount of platinum contained in the reaction electrode after forming the 0.5 mg / cm ^2, the amount of perfluorocarbon sulfonic acid was adjusted to be 1.2 mg / cm ^2.

  These electrodes have the same configuration for both the positive electrode and the negative electrode, and as shown in FIG. 2, the printed catalyst layer is on the electrolyte membrane side on both sides of the central portion of the proton conductive polymer electrolyte membrane having a slightly larger area than the electrode. The electrode / electrolyte assembly (MEA) was formed by bonding by hot pressing so as to be in contact with each other. Here, as the proton conductive polymer electrolyte, a perfluorocarbon sulfonic acid shown in (Chemical Formula 4) having a thickness of 25 μm was used.

  Two plate-like shapes are formed so that the electrode portion of the MEA fits into the square-shaped electrode hole in the center of the plate-like molded gasket provided with the electrode, cooling water, and gas manifold holes shown in FIG. The electrolyte membrane part around the MEA electrode is sandwiched between the molded gaskets, and the two gas plate-shaped bipolar plates shown in FIG. 5 are opposed to each other. A polymer electrolyte fuel cell was constructed by sandwiching a molded gasket.

  The bipolar plate used at this time was formed by press-molding a porous sheet obtained by preliminarily molding expanded graphite powder, and after applying water repellency treatment to the surface of the molded gas flow path, the reactivity shown in (Chemical Formula 2) After impregnating a mixed solution of oligomer and cyclohexane (mixing weight ratio 10: 2), it was prepared by heating at 85 ° C. for 48 hours. At this time, one surface of the bipolar plate is configured to have the gas flow path shown in FIG. 5, and a groove for cooling water flow path is formed on the opposite surface. The water repellent treatment was performed by heating a dispersion solution of a tetrafluoroethylene-hexafluoropropylene copolymer at about 350 ° C.

At this time the plate-shaped molded gasket used was a heat-resistant polyethylene terephthalate (PET) resin having a thickness of 100μm on a layer of the central portion, on both sides of the PET, the Lee isobutylene-by thickness 75μm and main chain skeleton ( of 1 to those of structure sandwiched by a material sheet layer described in), it was used by punching the necessary holes.

This polymer electrolyte fuel cell was used as a unit cell, and 50 polymer electrolyte fuel cells having the same configuration were stacked in the configuration schematically shown in FIG. At this time, also the gas seal portion near the cooling water flow path, using the material described in the Lee isobutylene as a main chain skeleton (Formula 1). A current collector plate, insulation plate, and end plate with holes for the required gas manifold and cooling water manifold are installed on both sides of the laminated battery, and bolts, springs, and nuts are used between the outermost end plates. Then, the polymer electrolyte fuel cell stack was constructed by tightening at a pressure of 20 kg / cm ² with respect to the electrode area.

The polymer electrolyte fuel cell stack is maintained at 75 ° C. while flowing cooling water, and humidified and heated so that the dew point is 73 ° C. on the negative electrode side, and the dew point is 68 ° C. on the positive electrode side. When humidified and heated air was supplied, a battery voltage of 49 V was obtained at no load. Further, the gas leak from the gasket part (peripheral part) of this battery was measured, but no gas leak was detected. Furthermore, when this battery was subjected to a continuous power generation test under the conditions of a fuel utilization rate of 80%, an oxygen utilization rate of 40%, and a current density of 0.7 A / cm ² , while maintaining a battery voltage of 31 V or more for 5000 hours or more, Power generation was possible without deterioration of battery voltage.

In the material represented by (Chemical Formula 1) having isobutylene as the main chain skeleton used in this example, the repeating number m of isobutylene in the configuration represented by (Chemical Formula 1) is 56 ≦ m ≦ 72, average 64, Benzoyl peroxide as a polymerization initiator was added in an amount of 0.2% by weight to the isobutylene oligomer to the functional group X and Y both having an allyl group, and radical polymerization by heating was performed. After curing, the degree of polymerization was examined and found to be about 9000.

The figure which showed the structure of the bipolar plate used by the reference example of this invention The figure which showed the structure of MEA of the bipolar plate used by the reference example of this invention The figure which showed the structure of the plate-shaped molded object gasket used by the reference example of this invention The figure which showed the structure of MEA used in the Example of this invention The figure which showed the structure of the plate-shaped molded object gasket used in the Example of this invention Cross-sectional configuration diagram of a polymer electrolyte fuel cell stack used in an example of the present invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Bipolar board 2 Gas flow path groove 3 Inlet gas manifold 4 Outlet gas manifold 5 Gas manifold 6 Electrode 7 Electrolyte membrane 8 Plate-shaped molded body gasket 9 Electrode fitting hole 15 Cooling water manifold 16 Cooling water flow path groove

Claims (1)

A polymer in which a pair of reaction electrodes sandwiching a solid polymer electrolyte membrane is sandwiched between a pair of bipolar plates for supplying and discharging fuel gas and oxidant gas to and from the reaction electrodes, and a cooling jig is attached to the bipolar plate. An electrolyte fuel cell,
It said bipolar plate, and a carbon material or a metal material, is constituted by a material shown in the Lee isobutylene as a main chain skeleton (of 1)
R ₁ and R ₂ are terminal non-functional groups,
Z is a functional group formed by combining the functional groups X and Y, and the functional groups X and Y are all allyl groups,
The repetition number m of isobutylene is an integer satisfying 56 ≦ m ≦ 72,
A polymer electrolyte fuel cell having a polymerization degree i of an integer of 8000 or more .

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