JP2012064481A - Manufacturing method of porous body layer for fuel battery, and fuel battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture a porous body layer for a fuel battery which can satisfy both an appropriate drainage and water retention for the fuel battery.SOLUTION: This manufacturing method includes: a first plating step where a part of a resin base material 52 is immersed in a plating bath 62 for a first prescribed time to form a porous body 48; and a second plating step where the other part of the resin base material 52 is immersed in the plating bath for a second prescribed time which is longer than the first prescribed time to form a porous body 50. The porous body 50 has smaller average pore diameter than the porous body 48.

Description

  The present invention relates to a method for producing a porous layer for a fuel cell and a fuel cell.

  An outline of a configuration of a main fuel cell (also referred to as a single cell) corresponding to the minimum unit of the fuel cell, in particular, a main part including an electrode portion will be described. As illustrated in FIG. 14, a membrane electrode assembly (MEA) 30 is configured in which the oxidation electrode catalyst layer 12 and the fuel electrode catalyst layer 14 are provided so as to face each other with the electrolyte membrane 10 interposed therebetween. An oxidation electrode diffusion layer 16 is provided outside the oxidation electrode catalyst layer 12, and a fuel electrode diffusion layer 18 is provided outside the fuel electrode catalyst layer 14. The oxidation electrode catalyst layer 12 and the oxidation electrode diffusion layer 16 disposed on one side of the electrolyte membrane 10 are also collectively referred to as an oxidation electrode (or cathode) 32, and the fuel electrode catalyst layer 14 and the fuel disposed on the other side of the electrolyte membrane 10. The pole diffusion layer 18 is also collectively referred to as a fuel electrode (or anode) 34.

  Further, an oxidation electrode side separator 26 in which an oxidant gas flow channel 20 and a cell refrigerant flow channel 22 are formed is formed outside the oxidation electrode diffusion layer 16, and a fuel gas flow channel 24 is formed outside the fuel electrode diffusion layer 18. The fuel electrode side separator 28 in which the cell refrigerant flow path 22 is formed is provided, and these are integrated by, for example, adhesion or pressure bonding to form the fuel cell 500.

  In general, a fuel cell including a cell stack in which a plurality of fuel cells 500 are stacked so as to obtain a desired electromotive force generally uses an oxidant gas such as oxygen gas or air flowing through the oxidant gas flow path 20 as an oxidant electrode catalyst. Fuel gas such as hydrogen gas and reformed gas flowing through the fuel gas flow path 24 is supplied to the layer 12 to the fuel electrode catalyst layer 14, and electricity between the oxidant gas and the fuel gas through the electrolyte membrane 10 is supplied. Power is generated by chemical reaction. The oxidant gas and the fuel gas that have flowed into the oxidant electrode 32 and the fuel electrode 34 from the upstream side of the oxidant gas channel 20 and the fuel gas channel 24 are respectively supplied to the cell reaction. Thereafter, the oxidant gas and the off-gas of the fuel gas are respectively sent to the downstream side of the oxidant gas flow path 20 and the fuel gas flow path 24 and discharged to the outside of the fuel cell 500 or the fuel cell.

  In general, in order for a fuel cell to generate favorable power, a predetermined amount of water (water content) is maintained with respect to the electrolyte membrane 10 using, for example, a fluorine-based ion exchange resin such as perfluoro-based or perfluorosulfonic acid-based. Thus, it is preferable to exhibit the function as a proton permeable membrane. In order to prevent so-called dry-up due to insufficient water content of the electrolyte membrane 10, for example, one or both of the reaction gases supplied into the fuel cell are humidified to adjust the moisture of the electrolyte membrane 10.

  On the other hand, if excessive moisture stays in the fuel cell, a phenomenon called so-called flooding occurs, and the supply of the raw material gas necessary for the reaction becomes insufficient, causing a decrease in power generation efficiency and unstable operating conditions. Can be a friend. Particularly on the oxidation electrode side, since water is generated by power generation, good drainage performance is required.

  For example, Patent Documents 1 to 4 are disclosed as fuel cells that can maintain / adjust the moisture content in the gas flow path and / or the fuel cell in an appropriate state.

  Patent Document 1 describes a fuel cell including a diffusion layer in which porous layers having different opening diameters are laminated so that the opening diameter decreases from the separator side toward the catalyst layer side.

  Patent Document 2 describes a gas diffusion layer in which the average pore diameter in the gas downstream portion is larger than the average pore diameter in the gas upstream portion.

  Patent Document 3 includes a porous material layer made of carbon having communication holes with a pore diameter of 10 nm to 500 nm, and a catalytic metal plating layer formed on the surface of the porous material layer, and a catalytic metal plating layer Is described for a fuel cell electrode whose surface is in contact with a solid polymer membrane.

  In Patent Document 4, the gas diffusion layer is formed by impregnating or adhering a solution in which a water-absorbent resin material is dispersed by spraying or screen printing so that the pore diameter changes according to the water content state on the electrolyte membrane side. A fuel cell in which a water absorbent resin is disposed is described.

JP 2000-058073 A JP 2001-057218 A JP 2006-100056 A JP 2008-147145 A

  Thus, for more stable operation of the fuel cell, it is required to maintain a suitable amount of water according to the operation conditions and electrode characteristics, and a fuel cell structure suitable for this requirement has been proposed.

  However, when producing a gas diffusion layer by a method as described in Patent Document 4, for example, it is difficult to accurately control the pore diameter. In addition, for example, cracks may occur during the production of the gas diffusion layer, so that desired drainage and water retention cannot be obtained, and appropriate power generation performance may not be exhibited.

  An object of this invention is to produce easily the porous body layer for fuel cells which can make the moderate drainage property and water retention of a fuel cell compatible.

  The configuration of the present invention is as follows.

  (1) A method for producing a porous layer for a fuel cell using a resin substrate having a predetermined average pore diameter as a material for a porous layer for a fuel cell, wherein a part of the resin substrate is removed for a first predetermined time. A first plating process for forming a first porous body part by immersing in a plating bath, and immersing the other part of the resin base material in a plating bath for a second predetermined time longer than the first predetermined time And a second plating process step for forming a second porous body part. A method for producing a porous layer for a fuel cell.

  According to the above configuration, the porous body layer for a fuel cell in which the pore diameter of the first porous body portion can be controlled to be larger than the pore diameter of the second porous body portion, and the pore diameter is inclined in the in-plane direction. Can be produced.

  (2) An electrolyte membrane and an oxidation electrode and a fuel electrode sandwiching both surfaces of the electrolyte membrane are provided, and power is generated by an electrochemical reaction between an oxidant gas supplied to the oxidation electrode side and a fuel gas supplied to the fuel electrode side. The oxidation electrode includes, in order from the electrolyte membrane side, an oxidation electrode catalyst layer, an oxidation electrode porous body layer, and an oxidation electrode diffusion layer. ), Wherein the second porous body portion is upstream of the oxidant gas in the flow direction, and the first porous body portion is the oxidant gas. In the fuel cell, the fuel cell porous body layer is disposed so as to be on the downstream side in the flow direction.

  According to the above configuration, the flow direction of the oxidant gas is achieved by arranging the fuel cell porous body layer so that the pore diameter on the upstream side in the flow direction of the oxidant gas is smaller than the pore diameter on the downstream side. Drying of the MEA including the electrolyte membrane facing the upstream portion side can be suppressed, and the power generation performance during high-temperature operation is improved.

  (3) A method for producing a porous layer for a fuel cell using a resin substrate having a predetermined average pore diameter as a porous material for a fuel cell, wherein a third conductive material is applied to a part of the resin substrate. A first vapor deposition process for forming a third porous body part by vapor deposition for a predetermined period of time, and a fourth predetermined period longer than the third predetermined period of time with a conductive material on the other part of the resin substrate. And a second vapor deposition treatment step of forming a fourth porous body portion by vapor deposition for a time.

  According to the above configuration, the pore diameter of the third porous body portion can be controlled to be larger than the pore diameter of the fourth porous body portion, and the pore diameter is inclined in the in-plane or surface thickness direction (stacking direction). Thus, a porous layer for a fuel cell can be produced.

  (4) An electrolyte membrane and an oxidation electrode and a fuel electrode sandwiching both surfaces of the electrolyte membrane are provided, and power is generated by an electrochemical reaction between an oxidant gas supplied to the oxidation electrode side and a fuel gas supplied to the fuel electrode side. The oxidation electrode includes, in order from the electrolyte membrane side, an oxidation electrode catalyst layer, an oxidation electrode porous body layer, and an oxidation electrode diffusion layer. ), The fourth porous body portion is upstream of the oxidant gas in the flow direction, and the third porous body portion is the oxidant gas. In the fuel cell, the fuel cell porous body layer is disposed so as to be on the downstream side in the flow direction.

  According to the above configuration, the flow direction of the oxidant gas is achieved by arranging the fuel cell porous body layer so that the pore diameter on the upstream side in the flow direction of the oxidant gas is smaller than the pore diameter on the downstream side. Drying of the MEA including the electrolyte membrane facing the upstream portion side can be suppressed, and the power generation performance during high-temperature operation is improved.

  (5) An electrolyte membrane and an oxidation electrode and a fuel electrode that sandwich both surfaces of the electrolyte membrane are provided, and power is generated by an electrochemical reaction between an oxidant gas supplied to the oxidation electrode side and a fuel gas supplied to the fuel electrode side. The oxidation electrode includes, in order from the electrolyte membrane side, an oxidation electrode catalyst layer, an oxidation electrode porous body layer, and an oxidation electrode diffusion layer. The porous body layer for fuel cells produced by the method described in (5), wherein the third porous body portion is on the oxidation electrode diffusion layer side and the fourth porous body portion is on the electrolyte membrane side. It is a fuel cell which arrange | positions the porous body layer for batteries.

  According to the above configuration, an appropriate capillary force can be generated by arranging the fuel cell porous body layer so that the pore diameter on the electrolyte membrane side is smaller than the pore diameter on the oxidation electrode diffusion layer side. The drainage performance on the oxidation electrode side is improved.

  (6) An electrolyte membrane and an oxidation electrode and a fuel electrode sandwiching both surfaces of the electrolyte membrane are provided, and power is generated by an electrochemical reaction between an oxidant gas supplied to the oxidation electrode side and a fuel gas supplied to the fuel electrode side. The oxidizing electrode includes an oxidizing electrode catalyst layer, an oxidizing electrode porous layer, and an oxidizing electrode diffusion layer in order from the electrolyte membrane side, and the oxidizing electrode porous layer has a predetermined average A part of the first resin base material having a pore diameter is immersed in a plating bath for a first predetermined time to form a first porous body part, and the other part of the first resin base material is the first part. A first porous body layer formed by immersing in a plating bath for a second predetermined time longer than the predetermined time to form a second porous body portion, and a second resin substrate having a predetermined average pore diameter A conductive material is deposited on a portion of the substrate for a third predetermined time to form a third porous body portion, and the second resin A second porous body layer formed by depositing a conductive material on the other portion of the material for a fourth predetermined time longer than the third predetermined time to form a fourth porous body portion, The first porous body layer is disposed such that the second porous body portion is on the upstream side in the flow direction of the oxidant gas and the first porous body portion is on the downstream side in the flow direction of the oxidant gas. The second porous body layer is disposed such that the third porous body portion is on the oxidation electrode diffusion layer side and the fourth porous body portion is on the electrolyte membrane side, and the first porous body layer It is a fuel cell formed by laminating the second porous body layer.

  (7) An electrolyte membrane and an oxidation electrode and a fuel electrode sandwiching both surfaces of the electrolyte membrane are provided, and power is generated by an electrochemical reaction between an oxidant gas supplied to the oxidation electrode side and a fuel gas supplied to the fuel electrode side. The oxidizing electrode includes an oxidizing electrode catalyst layer, an oxidizing electrode porous layer, and an oxidizing electrode diffusion layer in order from the electrolyte membrane side, and the oxidizing electrode porous layer has a predetermined average A conductive material is vapor-deposited on a part of the first resin base material having a pore diameter for a first predetermined time to form a first porous body part, and the other part of the first resin base material is electrically conductive. A first porous layer formed by vapor-depositing a functional material for a second predetermined time longer than the first predetermined time to form a second porous body portion, and a second having a predetermined average pore diameter A conductive material is deposited on a part of the resin base material for a third predetermined time to form a third porous body portion. A second porous layer formed by depositing a conductive material on the other part of the second resin base material for a fourth predetermined time longer than the third predetermined time to form a fourth porous body portion The first porous body layer is formed such that the second porous body portion is on the upstream side in the oxidant gas flow direction and the first porous body portion is on the downstream side in the oxidant gas flow direction. And arranging the second porous body layer so that the third porous body portion is on the oxidation electrode diffusion layer side and the fourth porous body portion is on the electrolyte membrane side, and the first porous body layer And the second porous body layer.

  (8) An electrolyte membrane, an oxidation electrode and a fuel electrode sandwiching both surfaces of the electrolyte membrane, wherein the oxidation electrode includes an oxidation electrode catalyst layer and an oxidation electrode diffusion layer in order from the electrolyte membrane side, In the fuel cell that generates electric power by an electrochemical reaction between the oxidant gas supplied to the fuel electrode and the fuel gas supplied to the fuel electrode side, the oxidation electrode provided between the oxidation electrode catalyst layer and the oxidation electrode diffusion layer A porous body layer having a pore diameter on the electrolyte membrane side smaller than a pore diameter on the oxidation electrode diffusion layer side, and a pore diameter on the upstream side in the flow direction of the oxidant gas; It is an oxidation porous body layer formed by laminating a second porous body portion smaller than the pore diameter.

  It becomes possible to achieve both moderate drainage and water retention.

1 is a diagram showing an outline of a configuration of a fuel cell 100. FIG. 4 is an enlarged cross-sectional view for explaining the configuration of an oxidized porous body layer 36. FIG. 2 is a diagram showing an outline of a configuration of a fuel battery cell 200. FIG. 4 is an enlarged cross-sectional view for explaining the configuration of an oxidized porous body layer 40. FIG. FIG. 2 is a diagram showing an outline of the configuration of a fuel cell 300. 4 is an enlarged cross-sectional view for explaining the configuration of an oxidized porous body layer 46. FIG. FIG. 6 is a diagram for explaining an example of a method for manufacturing the oxidized porous layer 40. It is a figure for demonstrating the modification of the manufacturing method of the oxidation porous body layer. FIG. 5 is a diagram for explaining an example of a method for producing the oxidized porous body layer 46. FIG. 5 is a diagram for explaining another example of the method for producing the oxidized porous body layer 46. FIG. 5 is a diagram for explaining another example of a method for manufacturing the oxidized porous body layer 46. FIG. 10 is a diagram for explaining still another example of the method for manufacturing the oxidized porous body layer 46. FIG. 10 is a diagram for explaining a modification of the manufacturing method of the oxidized porous body layer 46. It is the figure which showed the outline of the structure of the conventional fuel cell.

  Hereinafter, it explains in detail using a drawing. Note that in each embodiment described below, the same reference numerals are given to the same components, and the description thereof may be omitted or may be simply described. Also, the dimensions of each member in the drawing do not necessarily correspond to the actual dimensions of each member.

[Fuel battery cell 100]
The fuel cell 100 shown in FIG. 1 includes an oxidation electrode porous body layer 36 between the oxidation electrode catalyst layer 12 and the oxidation electrode diffusion layer 16, and between the fuel electrode catalyst layer 14 and the fuel electrode diffusion layer 18. In some cases, the fuel electrode porous body layer 38 can be provided, and the fuel cell 500 has the same configuration as that shown in FIG.

  As illustrated in FIG. 2, the porous resin base material 52 having a predetermined average pore diameter is subjected to a conductive treatment to form a conductive film 54, so that the average pore diameter and / or the pore diameter distribution of the pores 56 can be obtained. The adjusted porous layer can be applied as the oxidized extreme porous layer 36.

  In the embodiment of the present invention, the oxidation electrode diffusion layer 16 can have, for example, an average pore diameter of 10 μm or more, more specifically 10 μm to 200 μm, and more specifically 10 μm to 100 μm. If the average pore diameter of the oxidation electrode diffusion layer 16 is less than 10 μm, drainage may be deteriorated, gas diffusion may be inhibited, and power generation performance may be deteriorated.

  The oxidized porous body layer 36 includes, for example, Ni plating by a base treatment on a porous resin base material 52 made of, for example, tetrafluoroethylene or other fluororesin, and further a plating bath such as gold plating or gold sputtering. For example, the average pore diameter of the oxidized porous body layer 36 due to the presence of the pores 56 is approximately smaller than the pore diameter of the oxidized electrode diffusion layer 16. It can be about 0.1 μm to 10 μm. The oxidized porous body layer 36 generally has water repellency.

  More specifically, when the fuel battery cell 100 shown in FIG. 1 is operated at a relatively low temperature of, for example, about 25 ° C. to 60 ° C., the average pore size of the oxidized porous body layer 36 is, for example, 1 μm to It can be about 10 μm. If the average pore diameter of the oxidized porous body layer 36 is less than 1 μm, for example, the drainage property may be lowered, and the gas diffusion resistance may be increased, and the power generation performance may be lowered. Moreover, when the average pore diameter of the oxidized porous body layer 36 exceeds 10 μm, for example, gas diffusion resistance may decrease, and the amount of water contained in the electrolyte membrane 10 may decrease.

  On the other hand, when the fuel cell 100 shown in FIG. 1 is operated at a relatively high temperature of about 60 ° C. to 100 ° C., the average pore size of the oxidized porous layer 36 is set to, for example, about 0.1 μm to 1 μm. be able to. When the average pore diameter of the oxidized electrode porous layer 36 is less than 0.1 μm, for example, the drainage from the oxidized electrode may be deteriorated. Further, when the average pore diameter of the oxidized porous body layer 36 exceeds 1 μm, for example, the diffusion resistance may decrease, and the water retention may decrease. Here, the “average pore diameter” is an average value of equivalent circle diameters when the pore shape is regarded as a columnar shape or a conical shape. For example, a mercury porosimeter can be used to measure the average pore diameter of the oxidized electrode porous layer 36.

  Also, the porosity of the oxidized porous body layer 36 can be set to, for example, 50% to 80%, more specifically 70% to 80%. If the porosity of the oxidized porous layer 36 is less than 50%, for example, flooding may occur. On the other hand, if the porosity of the oxidized porous layer 36 exceeds 80%, for example, dry up may occur. For the measurement of the porosity, for example, form observation with a mercury porosimeter or SEM can be used.

  Further, the width in the stacking direction of the oxidized porous layer 36, that is, the thickness of the oxidized porous layer 36 is, for example, 200 μm or less, more specifically 20 μm to 200 μm, and more specifically 50 μm to 200 μm. be able to. When the thickness of the oxidized porous body layer 36 is less than 20 μm, the function as the oxidized porous body layer 36 may not be sufficiently exerted. On the other hand, when the thickness of the oxidized porous body layer 36 exceeds 200 μm, for example There is a possibility that the drainage performance is lowered.

  On the other hand, the fuel electrode diffusion layer 18 shown in FIG. 1 can have the same configuration as that of the oxidation electrode diffusion layer 16, for example, but is not limited to this, and any known configuration can be applied. It is. In addition, the fuel electrode porous layer 38 that is arbitrarily applied as necessary can be configured, for example, similar to the oxide electrode porous layer 36, but is not limited thereto, and any known public electrode layer 36 can be used. It is also possible to apply a configuration.

  According to this configuration, by controlling the thickness and average pore diameter of the oxidized porous body layer 36, for example, gas diffusion resistance is increased, and a decrease in the amount of water contained in the electrolyte membrane 10 can be suppressed.

[Fuel battery cell 200]
A fuel cell 200 shown in FIG. 3 has an oxidation electrode in which a first porous body portion 42 and a second porous body portion 44 are stacked in the cross-sectional direction of the fuel cell 200 instead of the oxidation electrode porous layer 36. Except for the provision of the porous body layer 40, it has the same configuration as the fuel cell 100 shown in FIG. The first porous body portion 42 is disposed on the oxidation electrode diffusion layer 16 side, and is adjacent to the oxidation electrode diffusion layer 16 in the embodiment shown in FIG. On the other hand, the 2nd porous body part 44 is arrange | positioned at the electrolyte membrane 10 side, and is adjacent to the oxidation-electrode catalyst layer 12 in embodiment shown in FIG.

  As illustrated in FIG. 4, conductive films 54 a and 54 b are formed on the oxidized porous body layer 40 by conducting conductive treatments on the porous resin base materials 52 a and 52 b, respectively. Further, the average pore diameters of the pores 56a and 56b are adjusted with the formation of the conductive films 54a and 54b, respectively. In the embodiment, the resin base materials 52a and 52b and the conductive films 54a and 54b can be made of the same material as the resin base material 52 and the conductive film 54 shown in FIG.

  In the embodiment, the average pore diameter of the pores 56 b formed in the second porous body portion 44 is configured to be smaller than the average pore diameter of the pores 56 a formed in the first porous body portion 42. . More specifically, the average pore diameter of the pores 56a formed in the first porous body portion 42 is, for example, 10 μm or less, more specifically about 10 μm to 0.1 μm, and more specifically 10 μm to 2 μm. It can be. On the other hand, the average pore diameter of the pores 56b formed in the second porous body portion 44 is, for example, 1 μm or less, more specifically about 1 μm to 0.01 μm, and more specifically 1 μm to 0.1 μm. be able to. By making the average pore diameter on the second porous body portion 44 side smaller than the average pore diameter on the first porous body portion 42 side, the pore diameter from the electrolyte membrane 10 side toward the oxidant gas flow path 20 side, That is, the volume of the fluid flow path is increased stepwise. Therefore, according to this structure, it becomes easy to move the generated water accompanying power generation to the oxidant gas flow path 20 side by utilizing the capillary force difference between the pores 56a and 56b, and a fuel cell having excellent drainage properties can be obtained. Can be provided.

  In the embodiment, the porosity of the first porous body portion 42 can be set to, for example, 50% to 80%, more specifically 70% to 80%. When the porosity of the first porous body portion 42 is less than 50%, for example, flooding may occur. On the other hand, when the porosity of the first porous body portion 42 exceeds 80%, it may dry up, for example. .

  Moreover, the porosity of the 2nd porous body part 44 can be 50%-80%, for example, More specifically, you can be 70%-80%. When the porosity of the second porous body portion 44 is less than 50%, for example, flooding may occur. On the other hand, when the porosity of the second porous body portion 44 exceeds 80%, it may dry up, for example. .

  In the embodiment, the thickness of the first porous body portion 42 and the thickness of the second porous body portion 44 may be the same or different. More specifically, the thickness of the first porous body portion 42 can be set to, for example, about 10 μm to 100 μm, and the thickness of the second porous body portion 44 can be set to, for example, about 10 μm to 100 μm. And the thickness as the oxidation pole body layer 40 whole can be about 20 micrometers-200 micrometers, for example.

<Method for Producing Oxidized Porous Layer 40>
As shown in FIG. 7, a resin base material 52 having a predetermined average pore diameter (for example, 3 μm) is prepared. In the embodiment, the porosity of the resin base material 52 can be set to, for example, 50% to 80%. The resin base material 52 is preferably made of a material having substantially uniform pore diameters in which pores having a pore diameter of 2.5 to 3.5 μm occupy 90% or more of the total pore volume. The first porous body portion 42 and the second porous member having different average pore diameters in the cross-sectional direction are obtained by performing the vapor deposition treatment of the conductive material by gold sputtering or the like from both surfaces of the resin base material 52 with different treatment times. The oxidized porous body layer 40 having the body part 44 can be produced. Generally, the average pore diameter on the second porous body portion 44 side is increased by making the conductive treatment time during the production of the second porous body portion 44 longer than the conductive treatment time during the production of the first porous body portion 42. Can be made smaller than the average pore diameter on the first porous body portion 42 side.

  On the other hand, as shown in FIG. 8, each of the first porous body portion 42 having a desired cross-sectional thickness and an average pore diameter, each of which is subjected to a conductive treatment on a resin base material processed into a desired shape, and It is also possible to produce the oxidized porous body layer 40 by preparing a material corresponding to the second porous body portion 44 in advance and joining them by, for example, pressure bonding or other appropriate methods.

[Fuel battery cell 300]
A fuel battery cell 300 shown in FIG. 5 is an oxidation in which a third porous body portion 48 and a fourth porous body portion 50 are stacked in the in-plane direction of the fuel battery cell 300 in place of the oxidized porous layer 36. Except for the provision of the polar porous body layer 46, it has the same configuration as the fuel cell 100 shown in FIG. In the embodiment, the fourth porous body part 50 branches from the oxidant gas flow path 20 to send the oxidant gas to the oxidant electrode 32 side, and to send out the oxidant off-gas. The oxidant gas supply side, that is, the upstream side (downward in FIG. 5) side of the oxidant gas flow direction, the third porous body portion 48 of the oxidant gas flow path 20 They are arranged so as to be on the discharge side, that is, on the downstream side (upward in FIG. 5) in the flow direction of the oxidizing gas.

  As illustrated in FIG. 6, conductive films 54 c and 54 d are formed on the third porous body portion 48 by conducting a conductive treatment on the porous resin base materials 52 c and 52 d, respectively. Further, the average pore diameters of the pores 56c and 56d are adjusted with the formation of the conductive films 54c and 54d, respectively. In the embodiment, the resin base materials 52c and 52d and the conductive films 54c and 54d can be made of the same material as the resin base material 52 and the conductive film 54 shown in FIG.

  In the embodiment, the average pore diameter of the pores 56d formed in the fourth porous body portion 50 is configured to be smaller than the average pore diameter of the pores 56c formed in the third porous body portion 48. . More specifically, the average pore diameter of the pores 56c formed in the third porous body portion 48 is, for example, 10 μm or less, more preferably about 10 μm to 0.1 μm, and more specifically about 5 μm. it can. On the other hand, the average pore diameter of the pores 56d formed in the fourth porous body portion 50 can be set to, for example, 1 μm or less, more preferably about 1 μm to 0.01 μm, and more specifically about 1 μm. By making the average pore diameter on the fourth porous body portion 50 side smaller than the average pore diameter on the third porous body portion 48 side, from the inlet side to the outlet side of the oxidant gas in the in-plane direction of the fuel cell. The pore diameter increases stepwise.

  In the embodiment, the porosity of the third porous body portion 48 can be set to, for example, 50% to 80%, more specifically 70% to 80%. If the porosity of the third porous body portion 48 is less than 50%, for example, flooding may occur. On the other hand, if the porosity of the third porous body portion 48 exceeds 80%, for example, dry-up may occur. .

  Moreover, the porosity of the 4th porous body part 50 can be 50%-80%, for example, More specifically, you can be 70%-80%. When the porosity of the fourth porous body portion 50 is less than 50%, for example, flooding may occur. On the other hand, when the porosity of the fourth porous body portion 50 exceeds 80%, for example, dry-up may occur. .

  In the embodiment, the thickness of the oxidized porous body layer 46 can be set to about 20 μm to 200 μm, for example. If the thickness of the oxidized porous body layer 46 is less than 20 μm, water retention may be reduced. Moreover, when the thickness of the oxidized porous body layer 46 exceeds 200 μm, drainage may be deteriorated.

  In addition, the area ratio in the in-plane direction of the fuel cell between the third porous body portion 48 and the fourth porous body portion 50 in the oxidized electrode porous body layer 46 is, for example, arranged on the inlet side of the oxidizing gas. The region of the fourth porous body portion 50 is about 1/20 to 1/3 of the entire oxidized electrode porous layer 46, and the remaining portion on the outlet side is the region of the third porous body portion 48. The porous layer 46 can be produced.

  According to the present embodiment, the fourth porous body portion 50 having a relatively small pore diameter is arranged on the inlet side of the oxidant gas, thereby operating at a relatively high temperature of about 60 ° C. to 100 ° C., for example. Even in such a case, it is possible to suppress a decrease in the amount of water contained in the electrolyte membrane 10, but by arranging the third porous body portion 48 having a relatively large pore diameter on the outlet side of the oxidizing gas, it is excellent. It is possible to provide a fuel battery cell having excellent drainage.

<Method for Producing Oxidized Polar Porous Layer 46>
As shown in FIG. 9, a resin base material 52 having a predetermined average pore diameter (for example, 3 μm) is prepared. In the embodiment, the porosity of the resin base material 52 can be set to, for example, 50% to 80%. The resin base material 52 is preferably made of a material having substantially uniform pore diameters in which pores having a pore diameter of 2.5 to 3.5 μm occupy 90% or more of the total pore volume. By performing the plating process of the conductive material in the plating bath 62 such as gold plating from both ends of the resin base material 52 with different processing times, the third porous body portion 48 having an average pore diameter different in the in-plane direction and The oxidized polar porous body layer 46 having the fourth porous body portion 50 can be produced. In general, the average pore diameter on the fourth porous body portion 50 side is made longer by increasing the conductive treatment time during the production of the fourth porous body portion 50 than the conductive treatment time during the production of the third porous body portion 48. Can be made smaller than the average pore diameter on the third porous body 48 side.

Further, as shown in FIG. 10, the oxidized porous body layer 46 can be suitably produced also by controlling the drawing speed from the plating bath 62. That is, the resin base material 52 immersed in the plating bath 62 is pulled out by a predetermined length at a predetermined speed v ₁ (for example, 5 cm / second), and a predetermined speed v ₂ (for example, 1 cm / second) slower than v _1. ) To pull out the remaining resin base material 52, thereby suitably producing the oxidized porous body layer 46 having the third porous body portion 48 and the fourth porous body portion 50 having different average pore diameters in the in-plane direction. be able to.

  On the other hand, as shown in FIGS. 11 and 12, the oxidized porous body layer 46 can also be produced by vapor deposition such as gold sputtering.

  As shown in FIG. 11, a part of one surface of the resin base material 52 is covered with a mask 64, and the exposed portion is subjected to vapor deposition (first vapor deposition). Next, the exposed portion and the mask portion of the resin base material 52 are switched, and the remaining portion of the resin base material 52 exposed from the mask 66 is subjected to a vapor deposition process (second vapor deposition process). At this time, the processing time of the first vapor deposition treatment and the second vapor deposition treatment are made different, and in this embodiment, the second vapor deposition treatment time is made longer than the first vapor deposition treatment time, so that in the in-plane direction. The oxidized porous body layer 46 having the third porous body portion 48 and the fourth porous body portion 50 having different average pore diameters can be suitably produced.

  In FIG. 12, first, the entire one surface of the resin base material 52 is subjected to a vapor deposition process for a predetermined time, and a part of the resin base material 52 is covered with a mask 68 to further vapor-deposit, thereby varying the overall processing time. Like the method illustrated in FIG. 11, the oxidized porous body layer 46 can be suitably produced.

  In addition, in the manufacturing method of the oxidation porous body layer 46 including a vapor deposition treatment process as shown in FIGS. 11 and 12, not only the one surface (front) side but also the other surface (back) side (see FIG. It is necessary to perform the same vapor deposition process (not shown) (see, for example, FIG. 7). At this time, for example, the oxidized porous body layer 46 and the oxidized porous body layer 40 are combined by changing the processing method and / or the processing time between the one surface side and the other surface side of the resin base material 52. It is also possible to produce an oxidized porous body layer having different pore sizes in the cross-sectional direction of the fuel cell.

  On the other hand, as shown in FIG. 13, the third porous body portion 48 and the fourth porous body, each having a desired average pore diameter and subjected to a conductive treatment on a resin base material processed into a desired shape, respectively. It is also possible to produce the oxide porous body layer 46 by producing a material corresponding to the part 50 in advance and bonding them by, for example, pressure bonding or other appropriate methods.

  The present invention can be used for various fuel cells, such as those that can be mounted on vehicles and other moving bodies, and stationary types.

  DESCRIPTION OF SYMBOLS 10 Electrolyte membrane, 12 Oxide electrode catalyst layer, 14 Fuel electrode catalyst layer, 16 Oxide electrode diffusion layer, 18 Fuel electrode diffusion layer, 20 Oxidant gas channel, 22 Cell refrigerant channel, 24 Fuel gas channel, 26 Oxide electrode Side separator, 28 Fuel electrode side separator, 30 Membrane electrode assembly (MEA), 32 Oxide electrode, 34 Fuel electrode, 36, 40, 46 Oxide porous body layer, 38 Fuel electrode porous body layer, 42, 44, 48, 50 porous body part, 52, 52a, 52b, 52c, 52d resin base material, 54, 54a, 54b, 54c, 54d conductive film, 56, 56a, 56b, 56c, 56d pore, 62 plating bath, 64, 66, 68 Mask, 100, 200, 300, 500 Fuel cell.

Claims (8)

A method for producing a porous layer for a fuel cell using a resin substrate having a predetermined average pore diameter as a porous material for a fuel cell,
A first plating treatment step of immersing a part of the resin base material in a plating bath for a first predetermined time to form a first porous body portion;
A second plating step of immersing the other part of the resin base material in a plating bath for a second predetermined time longer than the first predetermined time to form a second porous body part;
The manufacturing method of the porous body layer for fuel cells containing this. A fuel cell comprising an electrolyte membrane, an oxidation electrode and a fuel electrode sandwiching both surfaces of the electrolyte membrane, and generating electric power by an electrochemical reaction between an oxidant gas supplied to the oxidation electrode side and a fuel gas supplied to the fuel electrode side Because
The oxidation electrode includes, in order from the electrolyte membrane side, an oxidation electrode catalyst layer, an oxidation electrode porous body layer, and an oxidation electrode diffusion layer.
The oxidized porous layer is a porous layer for a fuel cell produced by the method according to claim 1,
The fuel cell porous body layer is formed so that the second porous body portion is on the upstream side in the flow direction of the oxidant gas and the first porous body portion is on the downstream side in the flow direction of the oxidant gas. A fuel cell that is arranged. A method for producing a porous layer for a fuel cell using a resin substrate having a predetermined average pore diameter as a porous material for a fuel cell,
A first vapor deposition process for forming a third porous body part by depositing a conductive material on a part of the resin base material for a third predetermined time; and
A second vapor deposition treatment step in which a conductive material is vapor deposited on the other portion of the resin base material for a fourth predetermined time longer than the third predetermined time to form a fourth porous body portion;
The manufacturing method of the porous body layer for fuel cells containing this. A fuel cell comprising an electrolyte membrane, an oxidation electrode and a fuel electrode sandwiching both surfaces of the electrolyte membrane, and generating electric power by an electrochemical reaction between an oxidant gas supplied to the oxidation electrode side and a fuel gas supplied to the fuel electrode side Because
The oxidation electrode includes, in order from the electrolyte membrane side, an oxidation electrode catalyst layer, an oxidation electrode porous body layer, and an oxidation electrode diffusion layer.
The oxidized porous body layer is a porous body layer for a fuel cell produced by the method according to claim 3,
The fuel cell porous body layer is formed such that the fourth porous body portion is on the upstream side in the flow direction of the oxidant gas, and the third porous body portion is on the downstream side in the flow direction of the oxidant gas. A fuel cell that is arranged. A fuel cell comprising an electrolyte membrane, an oxidation electrode and a fuel electrode sandwiching both surfaces of the electrolyte membrane, and generating electric power by an electrochemical reaction between an oxidant gas supplied to the oxidation electrode side and a fuel gas supplied to the fuel electrode side Because
The oxidation electrode includes, in order from the electrolyte membrane side, an oxidation electrode catalyst layer, an oxidation electrode porous body layer, and an oxidation electrode diffusion layer.
The oxidized porous body layer is a porous body layer for a fuel cell produced by the method according to claim 3,
A fuel cell in which the fuel cell porous body layer is disposed so that the third porous body portion is on the oxidation electrode diffusion layer side and the fourth porous body portion is on the electrolyte membrane side. A fuel cell comprising an electrolyte membrane, an oxidation electrode and a fuel electrode sandwiching both surfaces of the electrolyte membrane, and generating electric power by an electrochemical reaction between an oxidant gas supplied to the oxidation electrode side and a fuel gas supplied to the fuel electrode side Because
The oxidation electrode includes, in order from the electrolyte membrane side, an oxidation electrode catalyst layer, an oxidation electrode porous body layer, and an oxidation electrode diffusion layer.
The oxidized porous body layer is
A part of the first resin base material having a predetermined average pore diameter is immersed in a plating bath for a first predetermined time to form a first porous body part, and the other part of the first resin base material is A first porous body layer formed by immersing in a plating bath for a second predetermined time longer than the first predetermined time to form a second porous body portion;
A conductive material is deposited on a part of the second resin base material having a predetermined average pore diameter for a third predetermined time to form a third porous body portion. A second porous body layer formed by depositing a conductive material on the portion for a fourth predetermined time longer than the third predetermined time to form a fourth porous body portion,
The first porous body layer is disposed such that the second porous body portion is on the upstream side in the flow direction of the oxidant gas and the first porous body portion is on the downstream side in the flow direction of the oxidant gas. And
Disposing the second porous body layer so that the third porous body portion is on the oxidation electrode diffusion layer side and the fourth porous body portion is on the electrolyte membrane side;
A fuel cell formed by laminating the first porous body layer and the second porous body layer. A fuel cell comprising an electrolyte membrane, an oxidation electrode and a fuel electrode sandwiching both surfaces of the electrolyte membrane, and generating electric power by an electrochemical reaction between an oxidant gas supplied to the oxidation electrode side and a fuel gas supplied to the fuel electrode side Because
The oxidation electrode includes, in order from the electrolyte membrane side, an oxidation electrode catalyst layer, an oxidation electrode porous body layer, and an oxidation electrode diffusion layer.
The oxidized porous body layer is
A conductive material is deposited on a part of the first resin base material having a predetermined average pore diameter for a first predetermined time to form a first porous body portion. A first porous layer formed by depositing a conductive material on the portion for a second predetermined time longer than the first predetermined time to form a second porous body portion;
A conductive material is deposited on a part of the second resin base material having a predetermined average pore diameter for a third predetermined time to form a third porous body portion. A second porous body layer formed by depositing a conductive material on the portion for a fourth predetermined time longer than the third predetermined time to form a fourth porous body portion,
The first porous body layer is disposed so that the second porous body portion is on the upstream side in the oxidant gas flow direction and the first porous body portion is on the downstream side in the oxidant gas flow direction,
Disposing the second porous body layer so that the third porous body portion is on the oxidation electrode diffusion layer side and the fourth porous body portion is on the electrolyte membrane side;
A fuel cell formed by laminating the first porous body layer and the second porous body layer. Provided with an electrolyte membrane, an oxidation electrode and a fuel electrode sandwiching both surfaces of the electrolyte membrane, and the oxidation electrode includes an oxidation electrode catalyst layer and an oxidation electrode diffusion layer in order from the electrolyte membrane side, and is supplied to the oxidation electrode side In the fuel cell that generates electric power by an electrochemical reaction between the oxidant gas to be supplied and the fuel gas supplied to the fuel electrode side, the porous oxide layer provided between the oxidizing electrode catalyst layer and the oxidizing electrode diffusion layer Because
A first porous body portion having a pore diameter on the electrolyte membrane side smaller than a pore diameter on the oxidation electrode diffusion layer side;
A second porous body portion in which the pore diameter at the upstream portion in the flow direction of the oxidant gas is smaller than the pore diameter at the downstream portion;
An oxidized porous layer made by laminating layers.

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