JP2005302674A - Fuel cell provided with porous separator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technology of effectively removing moisture generated at a cathode through a separator. <P>SOLUTION: The fuel cell comprises an electrolyte layer 122, the cathode 126, a gas diffusion layer 140, and the separator 160. The separator includes a porous part 162 having a convex part 162a facing the gas diffusion layer 140. A reticulate member 170 having conductivity is arranged between the gas diffusion layer 140 and the porous part 162. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a fuel cell including a porous separator.

  The fuel cell includes a plurality of cells, and a separator is provided between two adjacent cells.

  In Patent Document 1, two separators are provided between two adjacent cells. Each separator has a plurality of convex portions on both surfaces, and a flow path is formed by the concave portions. The first separator is in contact with the first MEA (ion exchange membrane electrolyte / electrode assembly) at the plurality of convex portions formed on the first surface side, and the first separator, the first MEA, A hydrogen gas flow path through which hydrogen gas passes is formed between the recesses. Similarly, the second separator is in contact with the second MEA at the plurality of convex portions formed on the first surface side, and a concave portion is provided between the second separator and the second MEA. An oxygen gas flow path through which air (oxygen gas) passes is formed. In addition, the plurality of convex portions formed on the second surface side of the first separator are in contact with the plurality of convex portions formed on the second surface side of the second separator, and the two separators A cooling water flow path through which the cooling water passes is formed between the concave portions facing each other.

  The water (generated water) generated at the cathode permeates the porous second separator and moves to the cooling water flow path. Thereby, generation | occurrence | production of the flooding state in an oxygen gas flow path can be suppressed. The movement of the generated water is realized by generating a predetermined pressure difference between the pressure of the oxygen gas and the pressure of the cooling water.

Japanese National Patent Publication No. 11-508726

  However, the conventional technique has a problem that it is difficult to efficiently remove water generated at the cathode through the porous separator. This is because the porous separator is difficult to efficiently take in moisture.

  The present invention has been made to solve the above-described problems in the prior art, and an object thereof is to efficiently remove moisture generated by an electrode through a separator.

In order to solve at least a part of the problems described above, an apparatus of the present invention is a fuel cell,
An electrolyte layer;
An electrode layer provided on one side of the electrolyte layer;
A gas diffusion layer provided on the one side of the electrolyte layer and sandwiching the electrode layer with the electrolyte layer;
A separator provided on the one side of the electrolyte layer and sandwiching the gas diffusion layer with the electrode layer, wherein a reactive gas is supplied to the electrode layer via the gas diffusion layer And the separator includes a porous portion having a convex portion that constitutes a part of the reaction gas passage so as to face the gas diffusion layer; and
A mesh member having conductivity provided between the gas diffusion layer and the porous portion;
It is characterized by providing.

  In this apparatus, since the mesh member is provided between the gas diffusion layer and the porous portion, it is possible to suppress the gas diffusion layer from being deformed by being pressed by the convex portion of the porous portion. . For this reason, the gas diffusion layer can efficiently store moisture, and the porous portion can efficiently take in moisture stored in the gas diffusion layer from the convex portion via the mesh member. As a result, the separator can efficiently remove moisture generated by the electrode.

In the above device,
The mesh member is preferably a metal member.

  By doing so, the mesh member can exhibit relatively high conductivity.

  In addition, as a metal member, the member containing titanium can be used, for example. However, when the electrolyte layer contains fluorine atoms, the network member is preferably a member in which a titanium-containing substrate is formed with plating having corrosion resistance to fluorine.

In the above device,
The mesh member is provided in a region corresponding to the porous portion,
It is preferable that a hydrophilic treatment is applied to a partial region corresponding to the convex portion of the porous portion included in the mesh member.

  If it carries out like this, since a water | moisture content will become easy to be hold | maintained at the partial area | region of a mesh member, the porous part can take in a water | moisture content more efficiently.

In the above device,
The mesh member may be selectively provided in a region corresponding to the convex portion of the porous portion.

  By doing so, the amount of the mesh member used can be reduced, and the manufacturing cost of the fuel cell can be reduced.

  Note that the present invention can be realized in various forms, for example, in the form of a fuel cell, a fuel cell system including the fuel cell, and a device such as a moving body equipped with the fuel cell system. be able to.

Next, embodiments of the present invention will be described in the following order based on examples.
A. First embodiment:
A-1. Overall configuration of the fuel cell system:
A-2. Schematic configuration of the cell:
A-3. Specific cell configuration:
B. Second embodiment:
C. Third embodiment:

A. First embodiment:
A-1. Overall configuration of the fuel cell system:
FIG. 1 is an explanatory diagram showing a schematic configuration of the fuel cell system in the first embodiment. The fuel cell system is mounted on a vehicle.

  The fuel cell system includes a fuel cell stack 100, a fuel gas supply system for supplying fuel gas (hydrogen gas) to the fuel cell stack, an air supply system for supplying air to the fuel cell stack, and a fuel cell stack And a coolant supply system for supplying the coolant. The fuel cell system also includes a controller 600 for controlling the operation of the entire system.

  A fuel cell stack (hereinafter also simply referred to as “stack”) 100 is a polymer electrolyte fuel cell that is relatively small and excellent in power generation efficiency. The stack 100 includes a plurality of stacked cells. A plurality of internal passages are provided inside the stack 100. Specifically, inside the stack, an internal fuel gas passage 210 through which fuel gas passes, an internal oxidizing gas passage 220 through which oxidizing gas (air) passes, an internal cooling fluid passage 230 through which coolant flows, and a cooling gas (air) ) Through which an internal cooling gas passage 240 passes.

  The fuel gas supply system includes a hydrogen tank 302, a pressure reducing valve 304, and a flow rate control valve 306. The hydrogen tank 302 stores hydrogen gas (fuel gas) at a relatively high pressure. The pressure reducing valve 304 reduces the fuel gas supplied from the hydrogen tank 302 to a predetermined pressure. The flow control valve 306 adjusts the flow rate of the fuel gas. The fuel gas is supplied to the stack 100 through the fuel gas passage 310. When the fuel gas passes through the internal fuel gas passage 210, it is used for an electrochemical reaction inside the stack. The spent fuel off gas that has passed through the internal fuel gas passage 210 is discharged to the outside through the fuel off gas passage 390. A shutoff valve 392 is provided in the fuel off gas passage 390. The shut-off valve 392 is intermittently set to an open state, whereby the fuel off-gas is discharged from the stack 100.

  The air supply system includes an air blower 402. Air is supplied to the stack 100 via an air passage. Here, the air passage includes first and second external air passages 410 and 420 provided outside the stack, and an internal cooling gas passage 240. When the air passes through the internal cooling gas passage 240, the air functions as a cooling gas and cools the stack 100. In addition, the air functions as an oxidizing gas when passing through the internal oxidizing gas passage 220 and is used for an electrochemical reaction inside the stack. Spent air (oxidation off gas) that has passed through the internal oxidation gas passage 220 is discharged to the outside through the oxidation off gas passage 490.

  The coolant supply system includes a circulation pump 502 and a heat exchanger 504. The circulation pump 502 circulates the coolant (for example, water) between the circulation passage 510 provided outside the stack and the internal coolant passage 230. The coolant cools the stack 100 as it passes through the internal coolant passage 230. The heat exchanger 504 cools the coolant having a relatively high temperature discharged from the stack 100.

  In this embodiment, the air passing through the internal cooling gas passage 240 is supplied to the internal oxidizing gas passage 220, but instead, the internal oxidizing gas passage 220 and the internal cooling gas passage 240 have the following: Independently, air may be supplied.

  In this embodiment, the air that has passed through the internal cooling gas passage 240 is supplied to the internal oxidizing gas passage 220 through the second external air passage 420, but is replaced with the second external air passage 420. Thus, an air passage for supplying air that has passed through the internal cooling gas passage 240 to the internal oxidizing gas passage 220 may be provided inside the stack.

A-2. Schematic configuration of the cell:
FIG. 2 is an explanatory diagram schematically showing the configuration of cells inside the fuel cell stack 100. As shown in the figure, the cell 110 includes a membrane-electrode assembly (MEA) 120, two gas diffusion layers 130 and 140, and two separators 150 and 160.

  The MEA 120 includes an electrolyte membrane 122 and two electrode layers (catalyst layers) 124 and 126 formed on both sides of the electrolyte membrane. The first electrode layer 124 is an anode (hydrogen electrode), and the second electrode layer 126 is a cathode (oxygen electrode). As the electrolyte membrane, a membrane formed of a solid polymer material such as a fluorine-based resin can be used. For example, a Nafion membrane manufactured by DuPont can be used. As the electrode layer, a catalyst layer in which a catalyst such as platinum is supported on carbon particles can be used.

  Two gas diffusion layers (hereinafter also simply referred to as “diffusion layers”) 130 and 140 sandwich the MEA 120. The anode side diffusion layer 130 has a function of diffusing fuel gas supplied from the outside and supplying it to the anode 124, and the cathode side diffusion layer 140 diffuses air (oxygen gas) supplied from the outside to form a cathode. 126 has a function to supply to 126. The diffusion layer is made of a material having sufficient gas diffusibility and conductivity, such as carbon cloth woven from carbon fibers, carbon paper, and carbon felt.

  The two separators 150 and 160 sandwich the MEA 120 and the two diffusion layers 130 and 140. A plurality of holes and recesses are formed in the anode side separator 150 and the cathode side separator 160. The plurality of holes and recesses form internal passages 210, 220, 230, and 240 (FIG. 1). Specifically, the pair of holes of each separator is provided so as to penetrate through the plurality of cells when the plurality of cells are stacked. That is, the pair of holes of each separator forms an upstream inter-cell passage and a downstream inter-cell passage. Moreover, the recessed part of each separator is provided so that a pair of hole may be connected. That is, the recess of each separator forms an in-cell passage that allows fluid to flow between the upstream inter-cell passage and the downstream inter-cell passage.

  More specifically, each separator 150, 160 has a pair of holes constituting upstream and downstream inter-cell fuel gas passages 210a, 210c, and upstream and downstream inter-cell oxidizing gas passages 220a, 220c. And a pair of holes are formed. Each separator 150, 160 has a pair of holes constituting upstream and downstream inter-cell coolant passages 230a, 230c and a pair constituting upstream and downstream inter-cell cooling gas passages 240a, 240c. Are formed.

  FIG. 3 is an explanatory view schematically showing the cathode separator 160. FIGS. 3A and 3B respectively show the first surface Sc1 and the second surface Sc2 of the cathode-side separator 160 shown in FIG. As shown in the figure, the first surface Sc1 of the cathode side separator is formed with a recess that constitutes an in-cell oxidizing gas passage (cathode side passage) 220b. In addition, the second surface Sc2 is formed with a recess that constitutes the in-cell coolant passage 230b and a recess that constitutes the in-cell cooling gas passage 240b. The concave portion constituting the in-cell cooling liquid passage 230b is formed on the back surface of the upstream portion of the concave portion constituting the intra-cell oxidizing gas passage 220b, and the concave portion constituting the intra-cell cooling gas passage 240b is formed within the cell. It is formed on the back surface of the downstream portion of the recess that constitutes the oxidizing gas passage 220b.

  The anode side separator 150 is the same as the cathode side separator 160. However, the first surface Sa1 of the anode-side separator is formed with a recess that constitutes an in-cell fuel gas passage (anode-side passage). In addition, the second surface Sa2 is formed with a recess that constitutes the in-cell coolant passage 230b and a recess that constitutes the in-cell cooling gas passage 240b.

  In practice, a plurality of convex portions are provided in each concave portion constituting the in-cell gas passages 210b, 220b, 240b.

  FIG. 4 is an explanatory diagram schematically showing a cross section of the cell 110. As shown in the figure, the in-cell fuel gas passage (anode side passage) 210b is formed between the recess provided in the first surface Sa1 of the anode-side separator 150 and the anode-side diffusion layer 130, The oxidizing gas passage (cathode side passage) 220b is formed between the concave portion provided on the first surface Sc1 of the cathode side separator 160 and the cathode side diffusion layer 140. The in-cell coolant passage 230b and the in-cell cooling gas passage 240b are formed by combining recesses provided on the second surfaces Sa2 and Sc2 of the two separators 150 and 160. The upstream and downstream inter-cell oxidizing gas passages 220 a and 220 c are formed by a pair of holes provided in the separators 150 and 160.

  By the way, the anode-side separator 150 is a member including only a dense region. On the other hand, the cathode-side separator 160 is a composite member that includes a dense region 161 and a porous region 162. The dense region 161 and the porous region 162 are continuous from the first surface Sc1 side to the second surface Sc2 side of the cathode separator 160, respectively. For this reason, both the dense region 161 and the porous region 162 appear on the surface of the cathode-side separator 160. The porous region 162 is provided in the region P shown in FIGS.

  The dense regions included in the two separators 150 and 160 have a relatively small porosity and have a property of not allowing water and gas to pass therethrough. On the other hand, the porous region included in the cathode-side separator 160 has a relatively large porosity and has a property of allowing water and gas to pass therethrough.

  Note that the dense region and the porous region are formed using a conductive material. Specifically, the dense region and the porous region are respectively formed using a dense member and a porous member obtained by compression molding a mixture of carbon powder and a binder. Note that the porosity of the porous region can be changed by adjusting the shape and size of the carbon powder, the mixing ratio of the carbon powder and the binder, and the like. The cathode-side separator 160 can be formed, for example, by combining a dense member and a porous member that are individually prepared, and heating to a temperature equal to or higher than the melting temperature of the binder.

  By using the separators 150 and 160 as described above, the stack can be cooled by supplying the cooling gas (air) to the in-cell cooling gas passage 240b. Further, by supplying the cooling gas (air) to the in-cell cooling gas passage 240b, the moisture generated at the cathode 126 can be removed through the porous region 162. Specifically, the moisture generated at the cathode 126 is stored in the cathode side diffusion layer 140. The porous region 162 takes in moisture stored in the cathode-side diffusion layer 140 by capillary attraction. The moisture moves inside the porous region 162 and is discharged into the cooling gas (air) flowing through the in-cell cooling gas passage 240b.

  In the present embodiment, since the porous region 162 is provided between the downstream portion of the in-cell oxidizing gas passage 220b and the in-cell cooling gas passage 240b, the moisture generated inside the stack is made porous. It can be efficiently removed through the quality region 162. Specifically, the moisture generated inside the stack is vaporized into the oxidizing gas passing through the in-cell oxidizing gas passage 220b and goes downstream together with the oxidizing gas. For this reason, in the in-cell oxidizing gas passage 220b, the moisture content in the upstream portion is relatively small, and the moisture content in the downstream portion is relatively large. Therefore, by providing the porous region 162 in the downstream portion of the in-cell oxidizing gas passage 220b, it is possible to efficiently remove the moisture generated inside the stack through the porous region 162.

  Further, in this embodiment, the humidified oxidizing gas is supplied to the in-cell oxidizing gas passage 220b via the in-cell cooling gas passage 240b. For this reason, the humidified oxidizing gas can give moisture to the upstream portion of the in-cell oxidizing gas passage 220b having a relatively small amount of moisture, and can suppress drying of the upstream portion.

A-3. Specific cell configuration:
FIG. 5 is an explanatory diagram showing a specific structure of the cell 110Z in the comparative example. 5, the vicinity of the porous region (porous portion) 162 of the cathode-side separator 160 shown in FIG. 4 is enlarged. In the fuel cell stack, the plurality of cells are pressurized from both sides by fastening members (not shown) provided at both ends thereof. For this reason, as illustrated, the diffusion layers 130 and 140 are pressed and deformed by the convex portions of the separators 150 and 160, respectively. Thus, by applying pressure in the cell stacking direction, the electrical conductivity between the anode 124 and the anode side separator 150 and between the cathode 126 and the cathode side separator 160 is enhanced.

  FIG. 6 is an explanatory diagram showing a specific structure of the cell 110 in the first embodiment. FIG. 6 is substantially the same as FIG. 5 except that a mesh member 170 having conductivity is added. The mesh member 170 is provided between the cathode side diffusion layer 140 and the cathode side separator 160. More specifically, as described in FIG. 4, the cathode-side separator 160 includes a dense portion 161 and a porous portion 162, and the mesh member 170 includes the cathode-side diffusion layer 140 and the porous portion 162. Between. The top surface of the convex portion 162a on the first surface Sc1 side of the porous portion 162 is a facing surface that faces the cathode-side diffusion layer 140 and contacts the mesh member 170, and the side surface and the convex portion of the convex portion 162a. The bottom surface around 162a (that is, the bottom surface of the recess) is a passage forming surface that constitutes the wall surface of the in-cell oxidizing gas passage 220b without contacting the mesh member 170.

  FIG. 7 is an explanatory view showing a part of the mesh member 170 in an enlarged manner. The mesh member 170 is a member in which platinum (Pt) plating is formed on a mesh-like titanium (Ti) -containing substrate (Ti substrate or Ti alloy substrate). The size of each opening of the mesh member 170 is set to, for example, about 1 mm × about 1 mm. The mesh member 170 is obtained by applying Pt plating to a Ti-containing substrate obtained by expanding a Ti-containing sheet in which a plurality of cuts (perforations) are formed in a direction perpendicular to the cuts.

  By the way, in the comparative example (FIG. 5), the cathode side diffusion layer 140 is pressed by the convex part 162a of the porous part 162 and is deformed. As described above, the cathode-side diffusion layer 140 is formed of, for example, carbon cloth. When the cathode-side diffusion layer 140 is pressed by the protrusion 162a, the cathode-side diffusion layer 140 in the cathode-side diffusion layer 140 corresponds to the top surface of the protrusion 162a. The pores, in other words, the gaps between the carbon fibers are crushed. On the other hand, in this embodiment (FIG. 6), a mesh member 170 is provided between the cathode-side diffusion layer 140 and the porous portion 162. For this reason, even if the cathode side diffusion layer 140 is pressed by the convex portion 162a, the deformation of the cathode side diffusion layer 140 is suppressed. More specifically, in the area CA corresponding to the top surface of the convex portion 162a, the pores in the cathode side diffusion layer 140 are prevented from being crushed.

  If the configuration of the present embodiment is employed, moisture generated at the cathode 126 can be efficiently discharged to the in-cell cooling gas passage 240b. That is, as described above, the moisture generated at the cathode 126 is stored in the cathode side diffusion layer 140. Further, the cathode side diffusion layer 140 captures and stores moisture evaporated in the in-cell oxidizing gas passage 220b. The porous part 162 takes in the moisture stored in the cathode side diffusion layer 140 through the top surface of the convex part 162a. The absorbed moisture moves inside the porous portion 162 and is discharged into the in-cell cooling gas passage 240b. If the mesh member 170 is not provided, it is difficult for the porous portion 162 to efficiently take in moisture through the top surface of the convex portion 162a. This is because the pores in the corresponding area CA of the cathode-side diffusion layer 140 are crushed, which makes it difficult for moisture to permeate the corresponding area CA and to store water in the corresponding area CA. However, in the present embodiment, the mesh member 170 is provided between the cathode side diffusion layer 140 and the porous portion 162. For this reason, the pores in the corresponding area CA of the cathode-side diffusion layer 140 are prevented from being crushed, and moisture easily passes through the corresponding area CA and is easily stored in the corresponding area CA. Therefore, the porous portion 162 can efficiently take in moisture stored in the cathode-side diffusion layer 140 from the convex portion 162a through the mesh member 170. As a result, the cathode separator 160 can efficiently discharge the moisture generated at the cathode 126 to the in-cell cooling gas passage 240b, and can suppress the occurrence of a flooding state in the in-cell oxidizing gas passage 220b.

  In the present embodiment, since the mesh member 170 is provided, the output characteristics of the stack 100 can be improved. That is, as shown in FIG. 5, when the mesh member 170 is not provided, the oxygen gas passes through the corresponding region CA of the cathode side diffusion layer 140 and the electrode reaction field RF near the top surface of the convex portion 162a. The amount of oxygen gas supplied to the electrode reaction field RF is relatively small. For this reason, the concentration overvoltage of the cathode increases, and as a result, the output voltage of the stack decreases. On the other hand, when the mesh member 170 is provided as in this embodiment, the oxygen gas is near the top surface of the convex portion 162a via the mesh member 170 and the corresponding region CA of the cathode-side diffusion layer 140. The amount of oxygen gas supplied to the electrode reaction field RF is relatively large. For this reason, the concentration overvoltage of the cathode can be made relatively small, and as a result, a decrease in the output voltage of the stack can be suppressed.

  In this embodiment, as described above, since the porous portion 162 is provided in the downstream portion of the in-cell oxidizing gas passage 220b, the partial pressure of oxygen gas in the vicinity of the porous portion 162 is relatively low. . For this reason, when the mesh member 170 is not provided, the oxygen gas is particularly difficult to be supplied to the electrode reaction field RF. That is, when the porous portion 162 is provided in the downstream portion of the in-cell oxidizing gas passage 220b as in the present embodiment, the above-described effect due to the provision of the mesh member 170 becomes significant.

  Furthermore, in this embodiment, by providing the mesh member 170, the stress concentration in the compression direction received by the cathode side diffusion layer 140 is alleviated. More specifically, when the mesh member 170 is not provided, stress concentrates on the corresponding region CA of the cathode side diffusion layer 140, but by providing the mesh member 170, the cathode side diffusion layer 140 of the cathode side diffusion layer 140 is provided. The stress distribution is made uniform. For this reason, mechanical damage to the electrolyte membrane 122 can be alleviated, and as a result, the life of the electrolyte membrane 122 can be extended.

  By the way, the mesh member 170 of the present embodiment is a member in which Pt plating is formed on a mesh Ti-containing substrate as described above. Since the Ti-containing substrate has high strength, the stress concentration applied to the cathode-side diffusion layer 140 can be efficiently reduced. Further, since the Ti-containing substrate has a small specific gravity, the stack 100 can be reduced in weight. However, in this embodiment, a fluororesin ion exchange membrane (Nafion membrane) known as a perfluoro type membrane is used as the electrolyte membrane 122. Thus, when the electrolyte membrane 122 contains a fluorine atom, the Ti-containing substrate is corroded due to the fluorine. Therefore, in this embodiment, the Ti-containing base material is subjected to Pt plating having corrosion resistance against fluorine.

B. Second embodiment:
FIG. 8 is an explanatory diagram showing a specific structure of the cell 110B in the second embodiment. FIG. 8 is substantially the same as FIG. 6 except that the mesh member 170B is changed.

  In this embodiment, the mesh member 170B includes a hydrophilic treatment layer 171 that has been subjected to a hydrophilic treatment. Specifically, in the mesh member 170, a partial region corresponding to the convex portion 162a of the porous portion 162 is subjected to a hydrophilic treatment. The hydrophilic treatment layer 171 can be obtained by selectively applying a coating agent containing Nafion liquid and carbon to the partial region of the mesh member 170B.

  If the configuration of this example is adopted, moisture is easily retained in the hydrophilic treatment layer 171, and thus the porous portion 162 can take in moisture more efficiently via the hydrophilic treatment layer 171.

C. Third embodiment:
FIG. 9 is an explanatory diagram showing a specific structure of the cell 110C in the third embodiment. FIG. 9 is substantially the same as FIG. 6 except that the mesh member 170C is changed.

  In the first embodiment, the mesh member 170 is provided in a region corresponding to the entire porous portion 162. However, in this embodiment, the mesh member 170C is a region corresponding to the convex portion 162a of the porous portion 162. Only provided selectively.

  Even when the configuration of the present embodiment is adopted, the deformation of the cathode side diffusion layer 140 can be suppressed as in the first embodiment. Moreover, since the usage-amount of the mesh member 170C can be reduced, the manufacturing cost of a stack can be reduced.

  Similar to the second embodiment, the mesh member 170C may be subjected to a hydrophilic treatment.

  In addition, this invention is not restricted to said Example and embodiment, In the range which does not deviate from the summary, it can be implemented in a various aspect, For example, the following deformation | transformation is also possible.

(1) In the above embodiment, a member in which Pt plating is formed on a reticulated Ti-containing base material is used as the reticulated member. Instead, gold (Au) plating is applied to a reticulated stainless steel base material. Alternatively, a member formed with, or a net-like gold (Au) member may be used. In general, the net member may be a metal member having corrosion resistance to the environment inside the stack.

(2) In the above embodiment, a member (expanded member) obtained by expanding a metal sheet having a plurality of cut lines is used as the mesh member. It may be. Further, the net member may be a member in which a plurality of openings (for example, punch holes) are provided in a metal sheet.

  Moreover, in the said Example, although the net-like member which has a substantially square opening is used, it replaces with this and the net-like member which has an opening of another shape may be used. FIG. 10 is an explanatory view showing an enlarged part of the mesh member 170 ′. As illustrated, the mesh member 170 'has a substantially rectangular opening. The mesh member 170 ′ is formed by arranging a plurality of wires inside the frame-like wire. Even when such a net-like member 170 ′ is used, deformation of the cathode side diffusion layer 140 can be suppressed.

  In general, the net member only needs to have a plurality of openings having an arbitrary shape.

(3) In the said Example, although the metal member is used as a mesh member, a carbon member may be used as a mesh member. The carbon member preferably has higher rigidity than the cathode side diffusion layer 140. As the net-like carbon member, carbon paper in which a plurality of openings are formed can be used. However, the metal mesh member has an advantage that it can exhibit relatively high conductivity.

  In general, a net-like member having conductivity may be provided between the gas diffusion layer and the porous portion.

(4) In the above embodiment, the molding material for each separator contains carbon powder and a resin binder, but other molding materials may be used. For example, the molding material may include a metal material (metal powder) and a resin binder. Further, the dense region constituting each separator may be a metal member.

(5) In the above embodiment, the porous portion has an uneven surface in which the convex portion has a substantially rectangular cross-sectional shape. A surface may be provided. Generally, the porous part should just have the convex part which opposes a cathode diffusion layer.

(6) In the above embodiment, the cathode-side separator includes the porous portion. However, instead of this, the anode-side separator may include the porous portion. In this case, for example, a net-like member may be provided between the anode side diffusion layer 130 and the porous portion of the anode side separator.

It is explanatory drawing which shows schematic structure of the fuel cell system in 1st Example. 2 is an explanatory view schematically showing a configuration of cells inside the fuel cell stack 100. FIG. It is explanatory drawing which shows the cathode side separator 160 typically. 3 is an explanatory diagram schematically showing a cross section of a cell 110. FIG. It is explanatory drawing which shows the specific structure of the cell 110Z in a comparative example. It is explanatory drawing which shows the specific structure of the cell 110 in 1st Example. It is explanatory drawing which expands and shows a part of net-like member 170. FIG. It is explanatory drawing which shows the specific structure of the cell 110B in 2nd Example. It is explanatory drawing which shows the specific structure of the cell 110C in 3rd Example. It is explanatory drawing which expands and shows a part of net-like member 170 '.

Explanation of symbols

100 ... Fuel cell stack 110, B, C, Z ... Cell 120 ... MEA
122 ... Electrolyte membrane 124 ... Electrode layer (anode)
126 ... Electrode layer (cathode)
DESCRIPTION OF SYMBOLS 130 ... Anode side diffusion layer 140 ... Cathode side diffusion layer 142, 142C ... Contacted layer 144 ... Hydrophilic treatment layer 146 ... Water repellent treatment suppression layer 147 ... Water repellent treatment layer 150 ... Anode side separator 160 ... Cathode side separator 161 ... Dense Quality area (dense part)
162 ... porous region (porous portion)
162a ... convex portions 170, B, C, 170 '... mesh member 171 ... hydrophilic treatment layer 210 ... internal fuel gas passage 210a, 210c ... inter-cell fuel gas passage 210b ... in-cell fuel gas passage (anode side passage)
220 ... Internal oxidizing gas passage 220a, 220c ... Inter-cell oxidizing gas passage 220b ... In-cell oxidizing gas passage (cathode side passage)
230 ... Internal coolant passage 230a, 230c ... Inter-cell coolant passage 230b ... In-cell coolant passage 240 ... Internal cooling gas passage 240a, 240c ... Inter-cell cooling gas passage 240b ... In-cell cooling gas passage 302 ... Hydrogen tank 304 ... Pressure reducing valve 306 ... Flow control valve 310 ... Fuel gas passage 390 ... Fuel off gas passage 392 ... Shut-off valve 402 ... Air blower 410, 420 ... External air passage 490 ... Oxidation off gas passage 502 ... Circulation pump 504 ... Heat exchanger 510 ... Circulation passage 600 ... Controller

Claims (4)

A fuel cell,
An electrolyte layer;
An electrode layer provided on one side of the electrolyte layer;
A gas diffusion layer provided on the one side of the electrolyte layer and sandwiching the electrode layer with the electrolyte layer;
A separator provided on the one side of the electrolyte layer and sandwiching the gas diffusion layer with the electrode layer, wherein a reactive gas is supplied to the electrode layer via the gas diffusion layer And the separator includes a porous portion having a convex portion that constitutes a part of the reaction gas passage so as to face the gas diffusion layer; and
A mesh member having conductivity provided between the gas diffusion layer and the porous portion;
A fuel cell comprising: The fuel cell according to claim 1, wherein
The net member is a fuel cell, which is a metal member. The fuel cell according to claim 1 or 2,
The mesh member is provided in a region corresponding to the porous portion,
A fuel cell, wherein a hydrophilic region is applied to a partial region corresponding to the convex portion of the porous portion included in the mesh member. The fuel cell according to claim 1 or 2,
The net member is a fuel cell that is selectively provided in a region corresponding to the convex portion of the porous portion.

Images