JP2005174646A - Solid polymer fuel cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a solid polymer fuel cell capable of better restraining flooding. <P>SOLUTION: At least a catalyst layer 20, a gas diffusion layer 10, and a conductive gas separator 60 are arranged on both sides of a solid polymer electrolyte film 30, and fuel gas is guided to one side thereof, and oxidant gas is guided to the other side. A proton conductive intermediate layer 40c having pores is arranged at least at one side of the solid polymer electrolyte film 30 between the catalyst layer 20c and itself with the solid polymer electrolyte film 30 as an interface, and water is exhausted to an outer peripheral gap part 70 formed at the outer periphery of the intermediate layer 40c. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a structure of a polymer electrolyte fuel cell. In particular, the present invention relates to a configuration for improving water management in a polymer electrolyte fuel cell.

  In general, a polymer electrolyte fuel cell (hereinafter referred to as a fuel cell) is a gas separation in which a catalyst layer is provided on both sides of a solid polymer membrane, a gas diffusion layer is disposed on the outside thereof, and a gas flow path is provided from the outside. It is formed by holding with a vessel (gas separator). By supplying a fuel gas containing at least hydrogen to the fuel electrode of the fuel cell and an oxidant gas containing at least oxygen to the oxidant electrode side, the following reaction occurs, and electric energy can be taken out of the fuel cell. It becomes possible.

Fuel electrode side: H ₂ → 2H ⁺ + 2e ⁻ (1)
Oxidant electrode side: 2H ⁺ + 2e ⁻ + 1 / 2O ₂ → H ₂ O (2)
Here, in order to efficiently take out the electric energy generated at the fuel electrode and the oxidant electrode to the outside of the fuel cell, the fuel such as the electrical resistance of the constituent members constituting the fuel cell unit cell, the contact resistance between the constituent members, etc. It is necessary to reduce the internal resistance of the battery. Further, it is necessary that the fuel gas and the oxidant gas introduced into the electrodes of the fuel electrode and the oxidant electrode reach the catalyst layer satisfactorily through the gas diffusion layers arranged on the respective electrode sides.

  Therefore, the water (product water) generated at the oxidizer electrode by the reaction shown in the formula (2) is discharged better than the catalyst layer and the gas diffusion layer, and the water generated by the generated water in the catalyst layer and the gas diffusion layer It is important to prevent clogging and keep the gas supply to the catalyst layer stable.

  In order to solve such a problem, for example, the hydrophobicity is increased toward the catalyst layer side in the gas diffusion layer on the fuel electrode side so that the hydrophobicity is increased toward the catalyst layer side in the oxidant electrode side gas diffusion layer. In addition, those using gas diffusion layers each having a hydrophobic gradient are known (for example, see Patent Document 1).

Or, in order to prevent clogging of the gas diffusion layer by the generated water and to supply the fuel gas or oxidant gas satisfactorily to the catalyst layer, the opening diameter from the gas separator side to the catalyst layer side in the gas diffusion layer It is known that it is configured so that the value decreases. (For example, refer to Patent Document 2).
JP-A-7-134993 JP 2000-58073 A

  However, in the technique presented in Patent Document 1, the supply path of the fuel gas or the oxidant gas to the catalyst layer and the drainage path from the catalyst layer of generated water are the same path. For this reason, there was a problem that the gas supply path (drainage path) of the gas diffusion layer may be blocked by the generated water during fuel cell operation, and flooding may occur.

  Also in the technique described in Patent Document 2, as in Patent Document 1, the gas supply path to the catalyst layer and the drainage path from the catalyst layer of generated water are the same path, and flooding may occur. There was a problem. In addition, since the opening diameter of the gas diffusion layer is reduced from the gas separator side toward the catalyst layer, the electron conduction path of the gas diffusion layer is reduced, and the contact area between the gas diffusion layer and the gas separator is reduced. There was a problem that the internal resistance of the fuel cell increased.

  In view of the above problems, an object of the present invention is to provide a polymer electrolyte fuel cell that can further suppress flooding.

  The present invention provides a solid polymer fuel comprising at least a catalyst layer, a gas diffusion layer, and a conductive gas separator on both sides of an electrolyte membrane, and introducing a fuel gas on one side and an oxidant gas on the other side The battery comprises a proton conductive intermediate intervening layer having a gap in at least a part of the electrolyte membrane and the catalyst layer on at least one side of the electrolyte membrane, and an outer periphery of the intermediate intervening layer Water is discharged into the outer peripheral gap formed in

  An outer peripheral gap formed on the outer periphery of the intermediate intervening layer, having a proton conductive intermediate intervening layer having a gap in at least part of the electrolyte membrane and the catalyst layer on at least one side of the electrolyte membrane Drain the water. This makes it possible to remove moisture from the catalyst layer without hindering gas supply to the catalyst layer. In addition, it is possible to prevent moisture from entering the catalyst layer from the electrolyte membrane. As a result, flooding is further suppressed, and a polymer electrolyte fuel cell with excellent power generation characteristics can be provided.

  A first embodiment will be described. FIG. 1 shows the configuration of a fuel cell 1 used in a solid polymer fuel cell (hereinafter referred to as fuel cell). The fuel cell may be composed of one fuel cell 1 or a fuel cell stack formed by stacking a plurality of fuel cells 1.

  The fuel cell 1 is configured by laminating a solid polymer electrolyte membrane 30, an intermediate intervening layer 40, a catalyst layer 20, a gas diffusion layer 10, and a gas separator 60. Here, the intermediate intervening layer 40c, the catalyst layer 20c, the gas diffusion layer 10c, and the gas separator 60c are laminated on the surface of the solid polymer electrolyte membrane 30 on the oxidant electrode 1c side from the solid polymer electrolyte membrane 30 side. Further, the catalyst layer 20a, the gas diffusion layer 10a, and the gas separator 60a are laminated on the surface on the fuel electrode 1a side from the solid polymer electrolyte membrane 30 side. Between the gas separator 60 and the gas diffusion layer 10, a gas flow path 61 through which fuel gas or oxidant gas flows is configured. Here, the gas flow path 61 is configured by providing a groove on the surface of the gas separator 60 that contacts the gas diffusion layer 10. This groove may be provided on the plate forming the gas separator 60 by pressing, grinding, or the like, or may be configured by disposing ribs that form between the flow paths on the plate.

  Although the intermediate intervening layer 40 is disposed on the oxidant electrode 1c side of the solid polymer electrolyte membrane 30 here, it may be disposed on the fuel electrode 1a side. Alternatively, the intermediate intervening layer 40 may be disposed on both sides of the solid polymer electrolyte membrane 30, that is, on the oxidant electrode 1c side and the fuel electrode 1a side.

  As the intermediate intervening layer 40, a layer having proton conductivity and having voids 41 in the layer is used. For example, the porosity in the intermediate intervening layer 40 is increased in the region overlapping the downstream side compared to the region overlapping the upstream side of the gas flow path 61 formed between the gas diffusion layer 10 and the gas separator 60. Constitute. The porosity of the intermediate intervening layer 40 may be changed continuously in the gas flow direction, or may be changed stepwise.

  Further, a sealing material 50 is provided between the solid polymer electrolyte membrane 30 and the gas separator 60 so as to surround the outer periphery of the reaction surface. Thereby, the fuel gas and the oxidant gas existing in the gas flow path 61, the gas diffusion layer 10, the catalyst layer 20, and the intermediate intervening layer 40 are sealed in the respective reaction regions. At this time, on the oxidant electrode 1c side, an outer peripheral gap portion 70c that is a space sandwiched between the solid polymer electrolyte membrane 30 and the gas separator 60c on the outer periphery of the intermediate intervening layer 40c, the catalyst layer 20c, and the gas diffusion layer 10c. Is formed. Also on the fuel electrode 1a side, an outer peripheral gap portion 70a that is a space sandwiched between the solid polymer electrolyte membrane 30 and the gas separator 60a is formed on the outer periphery of the catalyst layer 20a and the gas diffusion layer 10a. The outer peripheral gap portion 70 communicates with the gas flow path 61 directly or through the gas diffusion layer 10. Or you may comprise so that it may communicate with the manifold which is not shown in figure which introduce | transduces or discharges fuel gas or oxidant gas to the gas flow path 61.

  In such a fuel battery cell 1, during operation, a power generation reaction as shown in the equation (1) occurs in the catalyst layer 20a on the fuel electrode 1a side, and in the catalyst layer 20c on the oxidant electrode 1c side, as shown in equation (2). Such a power generation reaction occurs. That is, in the catalyst layer 20c on the oxidant electrode 1c side, water is generated along with the power generation reaction. At this time, as shown in FIG. 2, the oxidant gas in the fuel cell 1 is supplied from the gas flow path 61c to the gas diffusion layer 10c and further supplied to the catalyst layer 20c. A part of the oxidant gas is used for the reaction in the catalyst layer 20c and consumed, while the other is unreacted and moves to the intermediate intervening layer 40c having a large porosity. Since the unreacted gas contains water generated in the catalyst layer 20 c, the water is likely to be condensed in the intermediate intervening layer 40. Further, even when condensed in the catalyst layer 20c, it becomes easier to move to the intermediate intervening layer 40 side due to the flow of the unreacted gas.

  Further, the unreacted gas passes through the intermediate intervening layer 40 and is discharged from the side surface 40v of the intermediate intervening layer 40 to the outer peripheral gap portion 70c. At this time, the moisture concentrated in the intermediate intervening layer 40 is also discharged to the outer peripheral gap 70c together with the unreacted gas.

  As a result, moisture can be removed from the catalyst layer 20c without hindering the diffusion of gas from the gas flow path 61c to the catalyst layer 20c. In other words, the fuel battery cell 1 in which the occurrence of flooding is prevented is disposed inside the battery. A stable configuration can be achieved without affecting the resistance. Moreover, since this effect becomes remarkable by increasing the gas flow rate, it is possible to stably operate even in a high current density region where a large amount of generated water is generated. Therefore, it is possible to stably provide a fuel cell suitable for mounting on a moving body such as a vehicle.

  The moisture discharged from the intermediate intervening layer 40 to the outer peripheral gap 70 can be discharged outside the fuel cell 1 through a gas discharge manifold (not shown) communicating with the outer peripheral gap 70c, for example.

  Next, the manufacturing process of such a fuel cell 1 will be described.

  First, a material having conductivity and porosity is used as a gas diffusion layer base material having both gas diffusibility and electrical conductivity. Here, a commercially available carbon paper (for example, carbon paper TGP-H-060 manufactured by Toray Industries, Inc.) is punched into a 5 cm square to prepare the gas diffusion layer 10. Carbon cloth or carbon nonwoven fabric may be used instead of carbon paper.

  Subsequently, water repellent with a fluorine-based aqueous dispersion solution such as polytetrafluoroethylene (PTFE) adjusted to a predetermined concentration as a water repellent (for example, a mixed solution of D-1 and pure water manufactured by Daikin Industries, Ltd.) A treatment solution is prepared. In order to perform the water repellent treatment, the gas diffusion layer 10 is immersed in this solution for 5 minutes, and then the gas diffusion layer 10 is pulled up from the solution and drained.

  Thereafter, the gas diffusion layer 10 is dried in the air or in a nitrogen atmosphere. The drying temperature should just be 100 degrees C or less, for example, it is made to dry for 30 minutes in 60 degreeC air | atmosphere. Further, in order to weld and fix the water repellent, baking is performed at 350 ° C. for 30 minutes. Thereby, the water-repellent-treated gas diffusion layer 10 is created. Although the water repellent treatment is performed here, a hydrophilic treatment may be performed. Alternatively, a carbon layer formed of carbon black powder and PTFE or the like may be disposed after drying after the water repellent treatment.

  Next, the catalyst layer 20 is formed on the surface of the water-repellent treated gas diffusion layer 10. For example, a catalyst powder such as carbon powder supporting a noble metal such as platinum, an alcohol solution of a solid polymer electrolyte (for example, Nafion solution manufactured by DuPont), pure water is mixed at a predetermined ratio, stirred, and degassed to obtain an electrode. A catalyst paste is prepared.

  This electrode catalyst paste is applied to the surface of the previously prepared water-repellent treated gas diffusion layer 10 by the doctor blade method to form the catalyst layer 20. In addition, the formation method of the catalyst layer 20 is not restricted to this, For example, it can form by arbitrary methods, such as a screen printing method and a spray method.

  After that, in an electrolyte solution similar to that used in the previous electrocatalyst paste (for example, Nafion solution manufactured by DuPont, etc.), camphor is mixed at a predetermined ratio as a pore-forming agent to prepare an intermediate intervening layer paste. . At this time, the space | interval of the intermediate | middle intervening layer 40 can be changed by changing the quantity of the camphor to mix. For example, when the fuel battery cell 1 is formed, the amount of camphor to be mixed is increased in the region overlapping the downstream side compared to the region overlapping the upstream side of the gas flow path 61. Alternatively, a plurality of types of intermediate intervening layer pastes are produced, and the intermediate intervening layer 40 having an arbitrary configuration is formed by applying the intermediate intervening layer paste in various ways in the plane or thickness direction of the catalyst layer 20. Also good. For example, when the fuel battery cell 1 is formed, an intermediate intervening layer paste in which the amount of camphor mixed is larger in the region overlapping the downstream side than the intermediate intervening layer paste applied to the region overlapping the upstream side of the gas flow path 61. Apply. Moreover, you may adjust electrolyte concentration using solvents, such as arbitrary alcohol.

  Subsequently, this intermediate intervening layer paste is applied to the surface of the catalyst layer 20 by a spray method. Thereby, the proton conductive intermediate intervening layer 40 having voids can be formed.

  In addition, although the space | gap of the intermediate | middle intervening layer 40 was formed with camphor, it is not restricted to this, Arbitrary pore forming agents, such as a calcium carbonate, and a foaming agent can be used. Or you may form a space | gap, without using a pore making agent or a foaming agent.

  Here, the intermediate intervening layer 40 is formed by applying the intermediate intervening layer paste to the catalyst layer 20 formed in the gas diffusion layer 10. However, the intermediate intervening layer 40 is formed by applying it to the surface of the solid polymer electrolyte membrane 30. Also good.

  Next, the gas diffusion layer 10 is disposed on both sides of the solid polymer electrolyte membrane 30 (for example, Nafion 112 manufactured by DuPont, about 50 μm thick, etc.). Here, the gas diffusion layer 10a coated only with the catalyst layer 20a is disposed on the fuel electrode 1a side so that the catalyst layer 20a contacts the solid polymer electrolyte membrane 30. On the oxidant electrode 1c side, the gas diffusion layer 10c coated with the catalyst layer 20c and the intermediate intervening layer 40c is disposed so that the intermediate intervening layer 40 is in contact with the solid polymer electrolyte membrane 30. Here, the gas diffusion layer 10c having the intermediate intervening layer 40c is disposed on the oxidant electrode 1c side of the solid polymer electrolyte membrane 30, but this is not restrictive. You may arrange | position to the fuel electrode 1a side, and may arrange | position the gas diffusion layer 10 which has the intermediate | middle intervening layer 40 and the catalyst layer 20 on both sides.

Subsequently, pressing is performed for 60 seconds at a temperature of 120 ° C. and a pressure of 20 kgf / cm ² by a hot pressing method, and the solid polymer electrolyte membrane 30, the catalyst layer 20, the gas diffusion layer 10, and the intermediate intervening layer 40 having the voids 41 are joined and integrated. To form a membrane electrode assembly (MEA).

  Furthermore, the gas separator 60 provided with the gas flow path 61 is arrange | positioned on both surfaces of MEA. In addition, a sealing material 50 is disposed along the outer periphery between the solid individual molecular electrolyte membrane 30 and the gas separator 60. The fuel cell 1 is configured by tightening the stacked surfaces so as to have a predetermined surface pressure. In addition, when using a fuel cell stack, after laminating | stacking the several fuel cell 1, it tightens so that between lamination surfaces may become a predetermined surface pressure.

  By manufacturing in this way, it is possible to configure the fuel cell 1 in which the proton conductive intermediate intervening layer 40 having voids is disposed between the solid polymer electrolyte membrane 30 and the catalyst layer 20.

  Next, the effect of this embodiment will be described.

  At least the catalyst layer 20, the gas diffusion layer 10, and the conductive gas separator 10 are provided on both sides of the solid polymer electrolyte membrane 30, and a fuel gas is introduced into one side thereof and an oxidant gas is introduced into the other side thereof. Proton-conducting material having voids in at least a part between the solid polymer electrolyte membrane 30 and the catalyst layer 20c on at least one side, here the oxidant electrode 1c side, with the solid polymer electrolyte membrane 30 as a boundary. An intermediate intervening layer 40c is provided, and moisture is discharged to the outer peripheral gap portion 70c of the intermediate intervening layer 40c. Since the intermediate intervening layer 40c is disposed between the solid polymer electrolyte membrane 30 and the catalyst layer 20c, moisture can be moved to the intermediate intervening layer 40c and discharged to the outer peripheral gap portion 70c. As a result, it becomes possible to remove moisture from the catalyst layer 20c without hindering gas supply to the catalyst layer 20c. Further, it is possible to prevent moisture from entering the catalyst layer 20c from the solid polymer electrolyte membrane 30. Thereby, flooding can be prevented and a fuel cell with excellent power generation characteristics can be provided.

  Further, the intermediate intervening layer 40 is disposed on the side where the oxidant gas is introduced (oxidant electrode 1c side). Water is generated with power generation, and the intermediate intervening layer 40 serving as a drainage path is disposed on the side where moisture easily enters the catalyst layer 20c from the solid polymer electrolyte membrane 30. The removal function can be improved efficiently. As a result, flooding can be suppressed and a fuel cell with excellent power generation characteristics can be provided.

  In addition, a gas flow path 61 through which fuel gas or oxidant gas flows is formed between the gas diffusion layer 10 and the gas separator 60. The porosity of the intermediate intervening layer 40 is configured to increase downstream as compared to upstream of the gas flow path 61c. As a result, it is possible to further remove moisture from the catalyst layer 20c on the downstream side of the gas flow path 61 where the amount of moisture contained in the catalyst layer 20c increases. As a result, flooding is further suppressed, and a fuel cell with excellent power generation characteristics can be provided.

  Next, a second embodiment will be described. The configuration of the fuel cell 1 is shown in FIG. Hereinafter, a description will be given centering on differences from the first embodiment.

Here, the intermediate intervening layer 40c is provided on the oxidant electrode 1c side, and the intermediate intervening layer 40a is also formed on the fuel electrode 1a side. Thereby, since it is possible to prevent moisture from moving from the polymer electrolyte membrane 30 to the catalyst layer 20a, it is possible to prevent flooding from occurring on the fuel electrode 1a side.

  Further, the intermediate intervening layer 40 is provided with a void 41 a communicating with the catalyst layer 20. Further, the intermediate intervening layer 40 is provided with a gap 41 b that opens toward the side surface 40 v of the intermediate intervening layer 40. That is, the gap 41 b is a gap communicating with the outer circumferential gap portion 70.

  Next, the manufacturing process of such a fuel cell will be described.

  Similarly to the first embodiment, the water-repellent treated gas diffusion layer 10 having the catalyst layer 20 is formed. Subsequently, an electrolyte solution (for example, a Nafion solution manufactured by DuPont) in which isopropyl alcohol is mixed at a predetermined ratio is prepared as a paste for forming the intermediate intervening layer 40 having voids on the surface of the catalyst layer 20. Thereafter, by stirring the mixed solution of isopropyl alcohol and the electrolyte solution, fine bubbles are generated in the intermediate intervening layer paste solution. A void 41 is formed in the intermediate intervening layer 40 by the bubbles. In addition, the formation method of a space | gap is not necessarily limited to this, You may use a pore making material and a foaming agent similarly to 1st Embodiment.

  The intermediate intermediate layer paste thus generated is applied to the surface of the catalyst layer 20 of the gas diffusion layer 10 by brushing to form the proton conductive intermediate intermediate layer 40 having voids. In addition, although application | coating of the intermediate | middle intervening layer paste was performed by brush painting, it is not this limitation, Arbitrary methods can be selected similarly to 1st Embodiment.

  Thereafter, the gas diffusion layer 10 is disposed on both sides of the solid polymer electrolyte membrane 30. Here, the gas diffusion layer 10 in which the intermediate intervening layer 40 and the catalyst layer 20 are formed is arranged on both surfaces of the solid polymer electrolyte membrane 30 so that the intermediate intervening layer 40 is in contact with the solid polymer electrolyte membrane 30. As in the first embodiment, the gas diffusion layer 10 in which the catalyst layer 20 and the intermediate intervening layer 40 are formed is disposed on one side of the solid polymer electrolyte membrane 30, and the intermediate intervening layer 40 is disposed on the other side. Alternatively, the gas diffusion layer 10 in which only the catalyst layer 20 is formed may be disposed.

Next, as in the first embodiment, an MEA is formed by hot pressing. Here, the MEA is formed by pressing at a temperature of 150 ° C. and a pressure of 20 kgf / cm ² for 60 seconds. In this way, by performing hot pressing using the intermediate interposed layer slurry containing bubbles, the gas in the bubbles in the intermediate interposed layer 40 is discharged to the catalyst layer 20 side. In addition, since the catalyst layer 20 permeates the gas but the solid polymer electrolyte membrane 30 side is cut off, the gas is discharged to the catalyst layer 20 side. As a result, a gap 41 a communicating with the catalyst layer 20 is formed in the intermediate intervening layer 40. A part of the gas is discharged through the side surface 40v. As a result, a gap 41 b communicating with the outer peripheral gap 70 is formed in the intermediate intervening layer 40.

  Thereafter, the gas separator 60 provided with the gas flow path 61 and the sealing material 50 are disposed on both surfaces of the MEA, and are tightened to a predetermined surface pressure to produce the fuel cell 1.

  The fuel cell 1 having the proton conductive intermediate intervening layer 40 having the gap 41 a communicating with the catalyst layer 20 between the solid polymer electrolyte membrane 30 and the catalyst layer 20 is thus produced. Can be configured.

  Next, the effect of this embodiment will be described. Here, only effects different from those of the first embodiment will be described.

  The intermediate intervening layer 40 has a gap 41 a communicating with the catalyst layer 20. As a result, the moisture generated in the catalyst layer 20 is more likely to move to the intermediate intervening layer 40 side, and the moisture discharge from the catalyst layer 20 is improved, so that the occurrence of flooding can be suppressed.

  In addition, the intermediate intervening layer 40 has a gap 41 b that communicates with the outer peripheral gap 70 formed between the solid polymer electrolyte membrane 30 and the gas separator 60. As a result, moisture is easily discharged from the intermediate intervening layer 40 to the outer peripheral gap portion 70. As a result, it is possible to remove the moisture that has moved to the intermediate intervening layer 40 to the gas flow path 61 side, prevent flooding more continuously, and provide a fuel cell with excellent power generation characteristics. .

  Next, a third embodiment will be described. The configuration of the fuel cell 1 is shown in FIG. In the following, the description will focus on parts that are different from the first and second embodiments.

  A part of the intermediate intervening layer 40 is configured to be formed along the outer periphery of the catalyst layer 20. Here, in addition to the outer periphery of the catalyst layer 20, the intermediate intervening layer 40 is configured along a part of the outer periphery of the gas diffusion layer 10. Thereby, the area of the surface where the intermediate intervening layer 40 is exposed in the outer peripheral gap 70 is increased.

  In addition, it is configured such that there are many voids 41b in the intermediate intervening layer 40 in the region overlapping the downstream side from the region overlapping the upstream side of the gas flow path 61 formed between the gas diffusion layer 10 and the gas separator 60. . The abundance ratio of the air gap 41b may be changed continuously in the gas flow direction or may be changed stepwise.

  Next, the manufacturing process of such a fuel cell will be described.

  As in the first embodiment, the water-repellent treated gas diffusion layer 10 coated with the catalyst layer 20 is formed. Subsequently, as in the second embodiment, a paste containing fine bubbles is produced in the intermediate intervening layer paste solution. Next, in the same manner as in the second embodiment, this intermediate intervening layer paste is applied to the surface of the catalyst layer 20 formed by applying to the gas diffusion electrode layer 10 by, for example, brushing, so that intermediate The intervening layer 40 is formed. At this time, the intermediate intervening layer paste is applied so as to cover the outer peripheral portion of the catalyst layer 20, so that a part of the intermediate intervening layer 40 exists on the outer peripheral portion of the catalyst layer 20. Here, in addition to the outer periphery of the catalyst layer 20, a part of the outer periphery of the gas diffusion layer 10 is covered.

  Next, similarly to the first embodiment, the gas diffusion layers 10 are disposed on both sides of the solid polymer electrolyte membrane 30. Here, the gas diffusion layer 10 having the catalyst layer 20 and the intermediate intervening layer 40 is disposed on both surfaces of the solid polymer electrolyte membrane 30 so that the intermediate intervening layer 40 is in contact with the solid polymer electrolyte membrane 30. As in the first embodiment, the gas diffusion layer 10 having the catalyst layer 20 and the intermediate intervening layer 40 is disposed on one side of the solid polymer electrolyte membrane 30, and the intermediate intervening layer 40 is provided on the other side. Instead, the gas diffusion layer 10 having only the catalyst layer 20 may be disposed.

Subsequently, the MEA is manufactured by pressing in a reduced pressure atmosphere at a temperature of 150 ° C. and a pressure of 20 kgf / cm ² for 60 seconds by a vacuum hot pressing method. By hot-pressing in the reduced pressure atmosphere using the intermediate interposed layer 40 slurry containing bubbles in this way, the gas in the bubbles in the intermediate interposed layer 40 can easily escape to the catalyst layer 20 side and the side surface 40v side. . As a result, voids 41a and 41b communicating with the catalyst layer 20 and the outer circumferential gap portion 70 can be formed.

  Then, the gas separator 60 provided with the gas flow path 61 is disposed on both surfaces of the MEA, and the fuel cell 1 is manufactured by tightening to a predetermined surface pressure.

  By producing in this way, there are voids 41a and 41b communicating with the catalyst layer 20 and the outer peripheral gap 70 between the solid polymer electrolyte membrane 30 and the catalyst layer 20 and on the outer peripheral portion of the catalyst layer 20. A fuel cell including the proton conductive intermediate intermediate layer 40 can be configured.

  Next, the effect of this embodiment will be described. Hereinafter, the effects different from those of the first and second embodiments will be mainly described.

  The intermediate intervening layer 40 has a gap 41 b that communicates with the outer peripheral gap 70 formed between the solid polymer electrolyte membrane 30 and the gas separator 60. As a result, moisture is easily discharged from the intermediate intervening layer 40 to the outer peripheral gap portion 70. As a result, it is possible to remove the moisture that has moved to the intermediate intervening layer 40 to the gas flow path 61 side, continuously prevent flooding, and provide a fuel cell with excellent power generation characteristics. .

  Here, in particular, a gas flow path 61 through which fuel gas or oxidant gas flows is formed between the gas diffusion layer 10 and the gas separator 60, and is formed between the solid polymer electrolyte membrane 30 and the gas separator 60. The gap 41 b communicating with the outer peripheral gap 70 is configured to increase from the upstream side to the downstream side of the gas channel 61. Thereby, the water moved to the intermediate intervening layer 40 on the downstream side of the gas channel 61 where a large amount of generated water is generated can be configured to be easily discharged by the outer peripheral gap portion 70. As a result, moisture removal from the catalyst layer 20 is promoted, flooding can be suppressed more continuously, and a fuel cell with excellent power generation characteristics can be provided.

  A part of the intermediate intervening layer 40 is formed along the outer periphery of the catalyst layer 20. As a result, the contact area between the catalyst layer and the intermediate intervening layer (water discharge path from the catalyst layer) and the area exposed to the outer peripheral gap 70 of the intermediate intervening layer 40 can be increased. In particular, when the air gap 41 b communicating with the outer peripheral gap portion 70 is formed, the number of the air gaps 41 formed by increasing this area can also be increased. As a result, it is possible to more effectively drain moisture from the catalyst layer and drain moisture from the intermediate intervening layer 40 to the outer circumferential gap portion 70. As a result, flooding can be further suppressed, and a fuel cell having excellent power generation characteristics can be provided.

  As a result, even in a high current density region where a large amount of generated water is generated, it is possible to operate more stably and continuously, and to stably provide a fuel cell more suitable for mounting on a moving body such as a vehicle. be able to.

  The present invention is not limited to the best mode for carrying out the invention, and it goes without saying that various modifications can be made within the scope of the technical idea described in the claims.

  The present invention can be applied to a polymer electrolyte fuel cell. In particular, the present invention can be applied to a fuel cell that requires high output, such as a fuel cell mounted on a moving body such as a vehicle.

It is a schematic block diagram of the fuel cell used for 1st Embodiment. It is explanatory drawing of the flow of the reactive gas and water | moisture content in 1st Embodiment. It is a schematic block diagram of the fuel cell used for 2nd Embodiment. It is a schematic block diagram of the fuel cell used for 3rd Embodiment.

Explanation of symbols

10 Gas diffusion layer 20 Catalyst layer 30 Solid polymer electrolyte membrane (electrolyte membrane)
40 Intermediate interposed layer 41 Void 41a Void communicating with catalyst layer 41b Void communicating with outer circumferential gap 60 Gas separator 61 Gas flow path 70 Outer circumferential gap

Claims (7)

In a polymer electrolyte fuel cell comprising at least a catalyst layer, a gas diffusion layer, and a conductive gas separator on both sides of an electrolyte membrane, and introducing a fuel gas on one side and an oxidant gas on the other side,
A proton conductive intermediate intervening layer having a gap is provided at least in part between the electrolyte membrane and the catalyst layer on at least one side of the electrolyte membrane, and is formed on the outer periphery of the intermediate intervening layer. A polymer electrolyte fuel cell, characterized in that moisture is discharged to an outer peripheral gap.   2. The polymer electrolyte fuel cell according to claim 1, wherein the intermediate intervening layer is disposed on a side where the oxidant gas is introduced. Between the gas diffusion layer and the gas separator, a gas flow path for flowing fuel gas or oxidant gas is formed,
The polymer electrolyte fuel cell according to claim 1, wherein the porosity of the intermediate intervening layer is configured to increase downstream as compared to upstream of the gas flow path.   The polymer electrolyte fuel cell according to claim 1, wherein the intermediate intervening layer has a gap communicating with the catalyst layer.   The polymer electrolyte fuel cell according to claim 1, wherein the intermediate intervening layer has a gap communicating with the outer peripheral gap. Between the gas diffusion layer and the gas separator, a gas flow path for flowing fuel gas or oxidant gas is formed,
The fuel cell according to claim 5, wherein a gap communicating with the outer peripheral gap portion is configured to increase downstream as compared with upstream of the gas flow path. The polymer electrolyte fuel cell according to any one of claims 1 to 6, wherein a part of the intermediate intermediate layer is formed along an outer periphery of the catalyst layer.

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