JP4723828B2 - Polymer electrolyte fuel cell - Google Patents

Description

  The present invention relates to an improvement in an electrode of a polymer electrolyte fuel cell, and more particularly to a structure for efficiently discharging water generated in an electrode from a catalyst layer or an electrode.

  Due to the recent increase in energy problems and environmental problems, fuel cells are attracting attention as a power source with high energy density and clean emissions. Among them, the polymer electrolyte fuel cell can be driven at a low temperature of 100 ° C. or less, and thus has good start-up characteristics. In particular, the polymer electrolyte fuel cell is actively being developed as a stationary distributed power source, an automobile power source, and a portable device power source.

  In a conventional polymer electrolyte fuel cell, as a configuration of an electrode, a catalyst layer is arranged at a portion in contact with the polymer electrolyte membrane, and then a gas diffusion layer and a current collector are laminated. Furthermore, fuel and oxygen flow paths are formed along the electrode surfaces. In many cases, the flow path is a separator that also serves as a current collector. A fuel cell is an apparatus that simultaneously performs electrochemical oxidation of fuel at a negative electrode and reduction of oxygen at a positive electrode, and obtains an output from a potential difference between both electrodes and a current taken out by an electrochemical reaction.

  The reaction at the positive electrode when the fuel cell is operated is a reaction that generates water using oxygen as a reactant. Therefore, a problem arises because the polymer electrolyte fuel cell is operated at 100 ° C. or lower. In other words, when the current density is small, the water generation rate is slow, so water is discharged to the outside as water vapor, but when the current density is large, the water condenses in the electrode and stays in the gas diffusion layer, The pores of the diffusion layer are blocked by water. So-called flooding occurs. As a result, the amount of oxygen supplied to the positive electrode catalyst layer is reduced, resulting in a problem that the amount of power generation is reduced. The higher the current density, the more conspicuous the influence of the decrease in the oxygen supply amount, and the faster the output decreases.

  Furthermore, water is also generated at the positive electrode by moving from the negative electrode to the positive electrode when ions are conducted through the polymer electrolyte membrane.

  In addition, when the negative electrode fuel is dry, a phenomenon called reverse diffusion occurs in which water generated at the positive electrode moves the polymer electrolyte membrane from the positive electrode to the negative electrode side, and water may be generated and stay at the negative electrode.

  In order to solve the above problems, each research institution has conventionally devised a member around the electrode, particularly a catalyst layer and a gas diffusion layer. For example, an example in which the gas diffusion layer is made of fibrous carbon, the fiber direction is one direction and the water flow direction is constant, the catalyst layer is divided into two parts, the polymer electrolyte membrane side and the gas diffusion layer side, An example in which the degree of water repellency is changed by changing the content of the solvent-soluble fluoropolymer contained in the layer (see, for example, Patent Document 1).

Moreover, the example which shows the manufacturing method which makes adhesion of water-repellent resin to a carbon fluid uniform in the process of manufacturing a gas diffusion layer is mentioned (for example, refer patent document 2).
JP 2001-357858 (page 4-6, FIG. 1) JP2003-109611 (page 3-4)

  However, flooding is unavoidable by either method. This is because there is a problem in the structure of the catalyst layer and gas diffusion layer and the drainage route of water in those layers.

  As for the structure of the catalyst layer and the gas diffusion layer, as shown in the background art, it is general to contain a water repellent. However, since water hardly penetrates into a layer having a high concentration of the water repellent, water is stored between the layer and the polymer electrolyte membrane. Further, in order for water to pass through the layer and reach the gas diffusion layer, a certain level of force is required due to the balance between the water repellency, the cross-sectional area of the passage site, and the surface tension of the water. Therefore, pressure is applied to the water between the layer and the polymer electrolyte membrane. From the above, it is inevitable that the amount of oxygen supplied to the catalyst layer decreases due to the stored water.

  Further, as a problem concerning the drainage route, first, it is mentioned that water must pass through a distance corresponding to the size of the gas diffusion layer from the in-plane center portion to the end portion of the gas diffusion layer. For example, when the gas diffusion layer is rectangular, the maximum distance of the drainage route is a distance from the center in the plane to the end of the side of the side of the gas diffusion layer. Another problem is that various resistances that hinder the movement of water exist in the drainage route. In other words, the water flow path and the hydrophobic part for the outside gas to enter are mixed, making the drainage route complex, blocking the flow path by causing gas accumulation near the drainage route, Since each member of the electrode is assembled by being pressed in the thickness direction, resistance caused by the fact that an effective volume as a drainage route cannot be obtained obstructs the smooth flow of water. As described above, according to the conventional method, since long-distance water has to travel along the route with resistance, it takes time for the water to move to the end of the electrode. As a result, the water generation rate becomes slower than that, so that a large amount of water is retained in the electrode, and flooding cannot be avoided.

  Further, the cost increases due to the deterioration of the water repellent agent, changing the manufacturing method to prevent the deterioration, and the kind and structure of the gas diffusion layer are limited. In order to avoid this, it is preferable to produce the drainage structure simply and inexpensively.

  An object of the present invention is to provide a structure for discharging water generated in an electrode of a polymer electrolyte fuel cell from the electrode and capable of being easily produced.

  In order to solve the above problems, in the present invention, in a polymer electrolyte fuel cell electrode comprising a polymer electrolyte membrane that conducts hydrogen ions and a pair of electrodes that sandwich the polymer electrolyte membrane, a polymer electrolyte membrane is provided. A catalyst layer that is disposed in contact with each other and that performs an electrochemical reaction, and is disposed on a side of the catalyst layer that faces the polymer electrolyte membrane. The catalyst layer is formed of a conductive material, and gas is generated by pores and gaps that exist between the conductive materials. A plurality of holes formed by a gas diffusion layer having permeability and a current collector disposed on a side of the gas diffusion layer facing the catalyst layer, the gas diffusion layer penetrating perpendicularly to the catalyst layer It is characterized by comprising.

  As a function of the hole, the side surface of the hole can discharge water in the same way as the end face of the gas diffusion layer, the number of holes can be increased by increasing the number of holes to discharge water, the discharge speed can be improved, and when water reaches the hole, The surface tension works and pulls water from the gas diffusion layer. Therefore, according to the present invention, it is possible to solve the problems of the structure of the catalyst layer and the gas diffusion layer and the drainage route of water in those layers, which are the problems described above. That is, the maximum distance of the water drainage route is ½ of the distance between adjacent holes, the distance that water passes through the electrode can be extremely shortened, and water can pass through the holes in the gas diffusion layer. It becomes possible to move to the side facing the catalyst layer without receiving any resistance. As described above, this structure can reduce the action of storing water in the catalyst layer.

  In addition, formation of holes in the gas diffusion layer can be performed easily and at low cost because a general technique such as pressing can be used.

  Further, the range of the hole width is characterized in that the lower limit is substantially the same as the width of the pores or gaps existing between the conductive materials of the gas diffusion layer, and the upper limit is 50 times the thickness of the gas diffusion layer. .

  This makes it easy for water that has reached the hole to flow out of the electrode due to the relationship between the surface tension of water and the flow path resistance in the gas diffusion layer. The flow becomes efficient. Also, when assembling the fuel cell, the gas diffusion layer is laminated and compressed together with the polymer electrolyte membrane, the catalyst layer, and the current collector. If the size of the hole, it is possible to retain water without collapsing the hole. Therefore, the water discharge function by the hole is not impaired. However, when the pore size exceeds the upper limit value, the pore area per unit area increases, so that the oxygen supply rate to the catalyst layer decreases and the output of the fuel cell decreases.

  Furthermore, in a plurality of holes present in the periphery, the distance between the pair of holes is characterized by being 1/2 or more of the gas diffusion layer thickness and 50 times or less of the gas diffusion layer thickness.

  This is an efficient distance for water generated from the central part of adjacent holes to reach the holes. However, when the hole interval is less than the lower limit value, the number of holes per unit area increases, so the oxygen supply rate to the catalyst layer decreases, and the output of the fuel cell decreases.

  Further, the hole is filled with a hydrophilic member.

  Accordingly, the interaction between the hydrophilic member and water causes an effect of drawing water into the hole, and promotes water discharge. Although not specifically limited here, the hydrophilic member is made of a polymer resin (for example, acrylic, cellulose, or polyvinyl alcohol resin) or a fiber material (for example, carbon or glass) that has been given water absorption by capillary force. It can be manufactured using a material selected from the group consisting of a fiber material as a substrate, a synthetic fiber made of acrylic, nylon, etc.), a porous ceramic material, or carbon.

  Further, it has a water absorption band that absorbs and retains water that has reached the hole, a part of the water absorption band is at least on the same surface as the surface of the gas diffusion layer facing the catalyst layer, and the opening of the hole It is characterized by being located.

  As a result, the water reaching the hole is absorbed and retained in the water absorption zone, so that even if the fuel cell is operated for a long time, the water does not overflow from the hole, and the water discharge performance can be maintained. In addition, water is not leaked outside the fuel cell.

  Although not specifically limited here, the water absorption band is composed of a polymer resin (eg, acrylic, cellulose, polyvinyl alcohol resin, etc.), an organic water-absorbing material such as fibrous paper or cloth, silica gel, It can be formed from one or more materials selected from the group consisting of inorganic water-absorbing materials such as alumina gel and zeolite.

  Alternatively, it has a water conduction zone for leading water that has reached the hole to the outside of the electrode, a part of the water conduction zone is at least on the same surface as the surface of the gas diffusion layer facing the catalyst layer, and the opening of the hole It is characterized by being located.

  Thereby, the water that has reached the inside of the hole travels through the water guiding zone and is discharged outside the gas diffusion layer. Accordingly, the water in the hole does not overflow even when operated for a long time, and the output of the fuel cell can be kept constant.

  Although not specifically limited here, the water conveyance zone is made of a fiber of a water-absorbing polymer resin (for example, cellulose-based or polyvinyl alcohol-based resin) or a material imparted with water absorption by capillary force (for example, carbon or glass). It can be produced by using at least one material selected from the group consisting of a fiber material as a substrate, a synthetic fiber made of acrylic, nylon or the like, or a porous ceramic material or carbon.

  Further, the present invention is characterized in that a water storage part for storing water derived from the water conveyance zone is disposed in the polymer electrolyte fuel cell.

  As a result, the water storage unit stores water in the water conveyance zone, so that even if it is operated for a long time, the water in the hole does not overflow and continues to flow through the water conveyance zone to the water storage unit, so the output of the fuel cell can be kept constant. It becomes. Although not specifically limited here, the water storage section is composed of a polymer resin (for example, acrylic, cellulose, polyvinyl alcohol resin, etc.), an organic water-absorbing material such as fibrous paper or cloth, silica gel, It can be formed from one or more materials selected from the group consisting of inorganic water-absorbing materials such as alumina gel and zeolite. If the water-absorbing material as described above is used, the water storage section has an effect of pulling water from the water conveyance zone. Therefore, the water conveyance zone also draws water from the hole, and water can be actively discharged to the outside of the electrode.

As another method for solving the above problems, in the present invention, in an electrode of a polymer electrolyte fuel cell comprising a polymer electrolyte membrane that conducts hydrogen ions and a pair of electrodes that sandwich the polymer electrolyte membrane,
A catalyst layer that is disposed in contact with the polymer electrolyte membrane and performs an electrochemical reaction, and a pore that is disposed on the side of the catalyst layer facing the polymer electrolyte membrane and is formed of a conductive material and exists between the conductive materials. And a gas diffusion layer having gas permeability by a gap and a current collector disposed on the side of the gas diffusion layer facing the catalyst layer, so that the gas diffusion layer cuts a plane parallel to the catalyst layer. It is characterized by comprising a plurality of cuts formed.

  As a function of the incision, the side surface of the incision can discharge water in the same way as the end face of the gas diffusion layer, the number of incisions can be increased to increase the number of parts that discharge water, the discharge speed can be improved, and when water reaches the incision, First, the surface tension works and pulls water from the gas diffusion layer. Therefore, according to the above invention, it is possible to solve the problems of the structure of the catalyst layer and the gas diffusion layer and the drainage route of water in those layers, which are the above-mentioned problems. That is, the maximum distance of the water drainage route is ½ of the distance between adjacent cuts, and the distance that water passes through the electrode can be extremely shortened. It is possible to move to the side facing the catalyst layer and the side surface of the gas diffusion layer without receiving any resistance. As described above, this structure can reduce the action of storing water in the catalyst layer.

  Further, since water freely flows along the notch, the amount of water cannot be distributed in the electrode, and the current distribution in the electrode is not biased regardless of long-time operation. Accordingly, the deterioration rate of the polymer electrolyte membrane can be reduced, and the life of the fuel cell can be extended.

  In addition, the formation of the cut into the gas diffusion layer can be performed easily and at low cost because a general technique such as press punching or cutting can be used.

  Furthermore, the range of the cut width is characterized in that the lower limit is substantially the same as the width of the voids and gaps existing between the conductive materials of the gas diffusion layer, and the upper limit is 50 times the thickness of the gas diffusion layer. .

  This makes it easier for water that reaches the cut to flow out of the electrode due to the relationship between the surface tension of the water and the flow path resistance in the gas diffusion layer. The flow becomes efficient. Also, when assembling the fuel cell, the gas diffusion layer is laminated and compressed together with the polymer electrolyte membrane, the catalyst layer, and the current collector. If the dimensions of the notch, the water can be retained without breaking the notch. Therefore, the water discharge function by cutting will not be impaired. However, when the cut dimension exceeds the upper limit value, the cut area per unit area increases, so that the oxygen supply rate to the catalyst layer decreases and the output of the fuel cell decreases.

  Furthermore, in the plurality of cuts, the interval between the cuts is characterized by being 1/2 or more of the gas diffusion layer thickness and 50 times or less of the gas diffusion layer thickness.

  This is an efficient distance for the water generated from the central part of adjacent cuts to reach the cut. However, when the cutting interval is less than the lower limit value, the number of cuttings per unit area increases, so that the oxygen supply rate to the catalyst layer decreases and the output of the fuel cell decreases.

  In addition, a hydrophilic member is filled in the cut.

  Thus, the interaction between the hydrophilic member and water produces an effect of drawing water into the cut and promotes water discharge. Although not specifically limited here, the hydrophilic member is made of a polymer resin (for example, acrylic, cellulose, or polyvinyl alcohol resin) or a fiber material (for example, carbon or glass) that has been given water absorption by capillary force. It can be manufactured using a material selected from the group consisting of a fiber material as a substrate, a synthetic fiber made of acrylic, nylon, etc.), a porous ceramic material, or carbon.

  Moreover, it is characterized by having a water absorption zone that absorbs and retains water that has reached the cut.

  Regarding the connection relationship between the water absorption zone and the gas diffusion layer, at least a part of the water absorption zone is arranged on the same plane as the surface of the gas diffusion layer facing the catalyst layer and at the upper part of the cut.

  Moreover, you may arrange | position so that a part of water absorption zone may contact the edge part of a notch. Here, the end of the cut refers to a portion on the same plane as the side surface of the gas diffusion layer of the cut.

  As a result, a part of the cut and the part of the water absorption zone are arranged so that the water reaches the inside of the cut and is absorbed and retained by the water absorption band. Water will not overflow and will continue to maintain water discharge performance. In addition, water is not leaked outside the fuel cell.

  Although not specifically limited here, the water absorption band is composed of a polymer resin (eg, acrylic, cellulose, polyvinyl alcohol resin, etc.), an organic water-absorbing material such as fibrous paper or cloth, silica gel, It can be formed from one or more materials selected from the group consisting of inorganic water-absorbing materials such as alumina gel and zeolite.

  Alternatively, it is characterized by having a water guide zone for leading water that has been cut into the outside of the electrode.

  Here, with respect to the connection relationship between the water conveyance zone and the gas diffusion layer, a configuration in which at least a part of the water conveyance zone is disposed on the same surface as the surface of the gas diffusion layer facing the catalyst layer and at the upper part of the cut To do.

  Moreover, you may arrange | position so that a part of water conveyance zone may contact the edge part of a notch.

  Thereby, since it arrange | positions so that a part of notch and a part of water conveyance zone may contact | connect, the water which reached the inside of a cut will pass along a water conveyance zone, and will be discharged | emitted outside a gas diffusion layer. Therefore, even if the operation is performed for a long time, the cut water does not overflow, and the output of the fuel cell can be kept constant.

  Although not specifically limited here, the water conveyance zone is made of a fiber of a water-absorbing polymer resin (for example, cellulose-based or polyvinyl alcohol-based resin) or a material imparted with water absorption by capillary force (for example, carbon or glass). It can be produced by using at least one material selected from the group consisting of a fiber material as a substrate, a synthetic fiber made of acrylic, nylon or the like, or a porous ceramic material or carbon.

  Further, the present invention is characterized in that a water storage part for storing water derived from the water conveyance zone is disposed in the polymer electrolyte fuel cell.

  As a result, the water storage unit stores water in the water conveyance zone, so that even if it is operated for a long time, the cut water does not overflow and continues to flow through the water conveyance zone to the water storage unit, so the output of the fuel cell can be kept constant. It becomes. Although not specifically limited here, the water storage section is composed of a polymer resin (for example, acrylic, cellulose, polyvinyl alcohol resin, etc.), an organic water-absorbing material such as fibrous paper or cloth, silica gel, It can be formed from one or more materials selected from the group consisting of inorganic water-absorbing materials such as alumina gel and zeolite. When the water-absorbing material as described above is used, the water storage section has an effect of pulling water from the water conveyance zone, so that the water conveyance zone also draws water from the cut, and water can be actively discharged to the outside of the electrode.

  As described above, in order to solve the above problems, in the present invention, an electrode of a polymer electrolyte fuel cell comprising a polymer electrolyte membrane that conducts hydrogen ions and a pair of electrodes that sandwich the polymer electrolyte membrane. In, a catalyst layer that is disposed in contact with the polymer electrolyte membrane and performs an electrochemical reaction, and is disposed on the side of the catalyst layer facing the polymer electrolyte membrane, is formed of a conductive material, and exists between the conductive materials It consists of a gas diffusion layer having gas permeability due to pores and gaps, and a current collector disposed on the side of the gas diffusion layer facing the catalyst layer, and the gas diffusion layer is perpendicular to the catalyst layer and straight The gas diffusion layer is provided with a plurality of holes penetrating therethrough.

  As a result, the water generated at the cathode or anode can reach the hole if it moves at least half the distance between adjacent holes, and the water that has reached the hole can be separated from the catalyst layer of the gas diffusion layer. It is possible to move to the opposite side without receiving any resistance. Therefore, this structure makes it possible to reduce the action of water remaining in the gas diffusion layer and the catalyst layer.

  Further, it is characterized in that a cut is formed in the gas diffusion layer.

  Thereby, since water freely flows through the cut, the amount of water cannot be distributed in the electrode, and the generated power can be kept constant regardless of long-time operation.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a schematic view of a cross section of an electrode according to the present invention. The structure is such that the cathode catalyst layer 21 and the anode catalyst layer 22 are joined to the polymer electrolyte membrane 10 with the polymer electrolyte membrane 10 interposed therebetween. Each of the cathode catalyst layer 21 and the anode catalyst layer 22 is disposed in contact with the cathode side gas diffusion layer 31 and the anode side gas diffusion layer 32 on the side facing the polymer electrolyte membrane 10, and further, the cathode side current collector. A body 41 and an anode current collector 42 are disposed. Here, the polymer electrolyte membrane 10 is Nafion 112 manufactured by DuPont, the cathode catalyst layer 21 and the anode catalyst layer 22 are PEFC catalysts manufactured by Tanaka Kikinzoku Kogyo Co., Ltd., the cathode side gas diffusion layer 31 and the anode side gas diffusion layer. For 32, carbon paper manufactured by Toray Industries, Inc. was used, and Ni net (100 mesh) was used as the cathode side current collector 41 and the anode side current collector 42. The above parts are not limited to the members used in the present embodiment, but may be other parts having the functions shown below.

  As a function of each element, the polymer electrolyte membrane 10 is a separation membrane that prevents the cathode and anode reactants from being mixed, and at the same time has a function of conducting ions between the two electrodes. In addition, the cathode catalyst layer 21 and the anode catalyst layer 22 perform an electrochemical reaction here, and can extract electric power from the potential difference and reaction rate of both electrodes. Further, the cathode side gas diffusion layer 31 and the anode side gas diffusion layer 32 are used to uniformly supply the reactants used in each catalyst layer to the entire catalyst layer and between each catalyst layer and the corresponding current collector. It is arranged to transfer electric charges. The current collector has a function of delivering charges to the gas diffusion layer and delivering charges to an external circuit connected to the fuel cell.

  In this embodiment, holes 110 are provided in the cathode-side gas diffusion layer 31 in order to discharge the electrochemical reaction and the water generated in the cathode by moving the polymer electrolyte membrane 10 from the electrode. This is shown in the cathode side gas diffusion layer top view of FIG. Incidentally, the cut surface at A-A 'corresponds to FIG. The cathode-side gas diffusion layer 31 had a thickness of 0.2 mm, a hole diameter of 0.5 mm, and an interval between adjacent holes of 1 mm. Further, on the side of the cathode-side current collector 41 facing the cathode-side gas diffusion layer 31, a water conduit 112 made of cellulose as a base material was installed. In the cathode current collector 41, a hole was formed at a position corresponding to the hole 110, and the water conduit 112 was inserted into the hole 110. As a result, a part of the water conveyance zone 112 is located on the same surface as the surface facing the cathode catalyst 21 of the cathode side gas diffusion layer 31 and at the opening of the hole 111. The accumulated water can be led out of the hole. Furthermore, a water reservoir 113 made of sponge was provided at the end of the water conduit 112 opposite to the fuel cell, and the water passing through the water conduit 112 was absorbed by the water reservoir 113.

  According to the above structure, the water generated at the cathode was discharged through the water conduit 112 through the hole 110. As a result, as shown in the current-voltage curve shown in FIG. 3, no significant voltage drop was observed even at high currents. As shown in FIG. 4, the change in the output voltage was extremely small as the change with time. Note that a drop in voltage at an elapsed time of 20 hours indicates that power generation was terminated by stopping the supply of hydrogen as fuel on the anode side. Further, it was observed that the water generated at the cathode once accumulated in the hole 110 through the water feeding zone 112 through the water guiding zone 112 during the power generation. Therefore, the power generation characteristics shown in FIGS. 3 and 4 are the effects obtained because the water generated at the cathode is appropriately drained to the outside, and it is shown that this structure is effective for flooding. .

  FIG. 5 is a schematic view of a cross section of an electrode according to the present invention. The structure and the function of each element are the same as those in the first embodiment.

  In this embodiment, a hole is connected to the cathode side gas diffusion layer 31 to form a cut 111. This is shown in the cathode side gas diffusion layer top view of FIG. As shown in FIG. 6, the gas diffusion layer was not completely cut off by the notch 111, but a part of the gas diffusion layer was connected so that the fuel cell was easily manufactured. However, of course, it may be completely separated, and the cut shape is not particular. Incidentally, the cut surface at B-B 'corresponds to FIG. The cathode-side gas diffusion layer 31 had a film thickness of 0.1 mm, a cut width of 0.2 mm, and an interval between adjacent cuts of 2 mm. Further, around the cathode side gas diffusion layer 31, a water absorption band 114 made of cellulose as a base material was installed so as to be in contact with the cathode side gas diffusion layer 31 and the end of the cut 111.

  According to the above structure, the water generated at the cathode was discharged to the water absorption zone 114 through the notch 111 and retained. The tendency of the power generation characteristics was the same as in FIGS. 3 and 4, and no large voltage drop was observed even at high currents, and the change in output voltage with time was very small. Further, during the power generation, it was observed that water generated at the cathode oozes into the cut 111 and water is absorbed into the water absorption zone 114. Therefore, it was shown that the water generated at the cathode was drained to the outside appropriately, and that this structure was effective against flooding.

  Moreover, in this structure, since it is not necessary to laminate the water conduction zone on the electrode, the fuel cell can be further reduced in size.

  As a comparative example, a fuel cell was produced without making the hole 110 in the member used in Example 1, and the power generation characteristics were evaluated. The results are as shown in the current-voltage curve of FIG. 3 and the graph showing the change with time of the output voltage of FIG. According to FIG. 3, a rapid drop in voltage is observed in a high current region of 0.8 A or more. In addition, according to FIG. 4, it can be seen that the power generation was completed in about one hour of power generation time. Both of these are caused by the fact that water has accumulated in the vicinity of the electrode, so that the supply rate of oxygen to the cathode catalyst layer is reduced by flooding.

The schematic diagram of the cross section of the electrode by this invention. The top view of the cathode side gas diffusion layer by this invention. The current-voltage curve of the fuel cell by Example 1 and a comparative example. The time-dependent change of the output voltage of the fuel cell by Example 1 and a comparative example. The schematic diagram of the cross section of the electrode by this invention. The top view of the cathode side gas diffusion layer by this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Polymer electrolyte membrane 21 Cathode catalyst layer 22 Anode catalyst layer 31 Cathode side gas diffusion layer 32 Cathode side gas diffusion layer 41 Cathode side current collector 42 Anode side current collector 110 Hole 111 Cut 112 Water conduction zone 113 Water storage part 114 Water absorption zone AA ′ Cut surface BB ′ of FIG. 1 Cut surface of FIG.

Claims (13)

In a polymer electrolyte fuel cell comprising a polymer electrolyte membrane that conducts hydrogen ions and a pair of electrodes that sandwich the polymer electrolyte membrane,
A catalyst layer disposed in contact with the polymer electrolyte membrane and performing an electrochemical reaction;
A gas diffusion layer disposed on the side of the catalyst layer facing the polymer electrolyte membrane, formed of a conductive material, and having gas permeability due to pores and gaps existing between the conductive materials;
A current collector disposed on a side of the gas diffusion layer facing the catalyst layer;
The gas diffusion layer and the current collector include a plurality of through portions formed so as to penetrate perpendicularly to the catalyst layer,
The penetrating portion includes an absorbing portion that absorbs water reaching the penetrating portion,
The absorbing portion is on the same surface as the facing surface that is the surface facing the polymer electrolyte membrane of the catalyst layer and is in contact with the catalyst layer, and a spacing portion spaced from the catalyst layer A polymer electrolyte fuel cell comprising:   The range of the width of the penetrating portion is that the lower limit is substantially the same as the width of pores and gaps existing between the conductive materials of the gas diffusion layer, and the upper limit is 50 times the thickness of the gas diffusion layer. 2. The polymer electrolyte fuel cell according to claim 1, wherein   2. The polymer electrolyte fuel cell according to claim 1, wherein the interval between the through portions is not less than ½ of the thickness of the gas diffusion layer and not more than 50 times the thickness of the gas diffusion layer.   The polymer electrolyte fuel cell according to any one of claims 1 to 3, wherein the penetrating portion is filled with a hydrophilic member. The polymer electrolyte fuel cell according to any one of claims 1 to 4, wherein the penetrating portion is a hole. The polymer electrolyte fuel cell according to any one of claims 1 to 4, wherein the through portion is a cut formed so as to cut a surface parallel to the catalyst layer. In a polymer electrolyte fuel cell comprising a polymer electrolyte membrane that conducts hydrogen ions and a pair of electrodes that sandwich the polymer electrolyte membrane,
A catalyst layer disposed in contact with the polymer electrolyte membrane and performing an electrochemical reaction;
A gas diffusion layer disposed on the side of the catalyst layer facing the polymer electrolyte membrane, formed of a conductive material, and having gas permeability due to pores and gaps existing between the conductive materials;
A current collector disposed on a side of the gas diffusion layer facing the catalyst layer;
The gas diffusion layer comprises a plurality of cuts provided so as to separate a part of the side surface of the gas diffusion layer perpendicular to the catalyst layer,
In the same plane as the gas diffusion layer, it comprises an absorption part that absorbs water that has reached the cut,
The polymer electrolyte fuel cell according to claim 1, wherein at least a part of the absorbing portion is in contact with an end of the cut. The polymer electrolyte fuel cell according to claim 7, wherein the whole of the plurality of cuts has a meander shape.   The lower limit of the range of the cut width is substantially the same as the width of pores or gaps existing between the conductive materials of the gas diffusion layer, and the upper limit is 50 times the thickness of the gas diffusion layer. The polymer electrolyte fuel cell according to any one of claims 7 and 8.   9. The polymer electrolyte according to claim 7, wherein the interval between the cuts is ½ or more of the thickness of the gas diffusion layer and 50 times or less of the thickness of the gas diffusion layer. Fuel cell. The polymer electrolyte fuel cell according to any one of claims 1 to 10 , wherein the absorption part is a water absorption zone for holding water. The polymer electrolyte fuel cell according to any one of claims 1 to 10 , wherein the absorption part is a water guide zone for leading water out of the catalyst layer. The polymer electrolyte fuel cell according to claim 12 , further comprising a water storage unit that stores water derived from the water conveyance zone.

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