JP2006310220A - Fuel cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cell which has a sealing structure of each unit cell and can be made light and thin and can obtain an ample power output, by enhancing the contact pressure of an electrode plate. <P>SOLUTION: The fuel cell has a solid polymer electrolyte plate 1, a cathode electrode plate 2 fixed on one side of the electrolyte plate 1, an anode electrode plate 3 fixed on the other side of the electrolyte plate 1, a cathode metal plate 4 fixed on the surface of the cathode electrode plate 2 and making gas to flow to the inner surface side, and an anode metal plate 5 fixed on the surface of the anode electrode plate 3 and making fuel flow inside. The circumference of both plates 4, 5 are in the electrically insulated and sealed state, passage grooves are formed at least on the inside of the anode metal plate 5 and a convex and curved contact part 5r is formed between the passage grooves 9 that is formed in parallel. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a fuel cell having a structure in which a positive and negative electrode plate and a solid polymer electrolyte are sandwiched between a pair of metal plates, and more particularly to a polymer fuel cell capable of reducing the thickness while maintaining output.

  Polymer fuel cells that use solid polymer electrolytes such as polymer electrolytes have high energy conversion efficiency, are thin, small, and lightweight, and are therefore being actively developed for household cogeneration systems and automobiles . As a conventional structure of such a fuel cell, one shown in FIG. 7 is known (for example, see Non-Patent Document 1).

  That is, as shown in FIG. 7, the anode 101 and the cathode 102 are disposed with the solid polymer electrolyte membrane 100 interposed therebetween. Further, the unit cell 105 is configured by being sandwiched by a pair of separators 104 via a gasket 103. Each separator 104 is formed with a gas flow path groove. A flow path for reducing gas (for example, hydrogen gas) is formed by contact with the anode 101, and an oxidizing gas (for example, for example, hydrogen gas) is contacted with the cathode 102. Oxygen gas) flow paths are formed. Each gas is supplied to the electrode reaction (chemical reaction at the electrode) by the action of the catalyst supported in the anode 101 or the cathode 102 while flowing through each flow path in the unit cell 105, and the generation of current and ions Conduction occurs.

  A large number of the unit cells 105 are stacked, and the unit cells 105 are electrically connected in series to constitute the fuel cell N, and the electrode 106 can be taken out from the unit cells 105 at both ends. Such a fuel cell N is attracting attention as a power source for electric vehicles and a distributed power source for home use in various applications because of its clean and high efficiency.

  On the other hand, with the recent activation of IT technology, mobile devices such as mobile phones, notebook computers, and digital cameras tend to be frequently used, but most of these power sources use lithium ion secondary batteries. However, as mobile devices become more sophisticated, power consumption is increasing, and clean and highly efficient fuel cells are attracting attention as power sources.

  However, in the conventional structure as shown in FIG. 7, there is no degree of freedom in the structure. Therefore, there is a problem in that it is difficult to reduce the thickness and size and increase the degree of freedom of shape required as a power source for mobile devices, and the maintenance property is poor. There was also. In addition, it is difficult to supply the redox gas so as not to mix with each other in the fuel cell and to seal it, and it is difficult to reduce the size and weight of the fuel cell while satisfying these conditions. Met.

  By the way, the following Patent Document 1 discloses a solid polymer electrolyte membrane / electrode assembly, a cathode-side metal plate in which a flow channel for an oxidant gas is formed, and an anode-side metal plate in which a flow channel for fuel gas is formed. A fuel cell having a structure in which the peripheral edges of the metal plates on both sides are fastened with fixing pins and sealed with a gas packing around the inside is disclosed. Then, press forming is used when the flow path grooves are formed in the anode side metal plate or the like.

  However, a flat contact surface is formed between the flow channel grooves on the inner surface of the metal plate, and the contact pressure is evenly distributed. Then, the contact pressure between the electrode plate and the metal plate may not be obtained sufficiently. When the contact pressure is insufficient, there is a problem that the electrical resistance of the contact increases and the output of the fuel cell decreases.

Nikkei Mechanical separate volume "Fuel Cell Development Frontline" Date of issue: June 29, 2001, Publisher: Nikkei BP, Chapter 3, PEFC, 3.1 Principles and Features p46 JP-A-8-162145

  Therefore, an object of the present invention is to provide a fuel cell that has a sealing structure for each unit cell, can be reduced in weight and thickness, and can obtain a sufficient output by increasing the contact pressure of the electrode plate. There is.

The above object can be achieved by the present invention as described below.
That is, the fuel cell of the present invention includes a plate-shaped solid polymer electrolyte, a cathode-side electrode plate disposed on one side of the solid polymer electrolyte, an anode-side electrode plate disposed on the other side, and the cathode A cathode-side metal plate that is disposed on the surface of the side electrode plate and allows gas to flow to the inner surface side, and an anode-side metal plate that is disposed on the surface of the anode-side electrode plate and allows fuel to flow to the inner surface side A fuel cell comprising a metal plate on both sides sealed in a state of being electrically insulated, and at least an inner surface of the anode-side metal plate is formed with a flow channel groove. A convex curved contact portion is formed between the channel grooves formed in parallel.

  According to the fuel cell of the present invention, the cathode side metal plate enables the gas to flow to the cathode side electrode plate, and the anode side metal plate enables the fuel to flow to the anode side electrode plate. An electrode reaction can be caused by the plate, and an electric current can be extracted from the metal plate. At that time, if a metal plate is used for thinning as in the present invention, it becomes difficult to maintain the contact pressure with the electrode plate. Since the curved curved contact portion is formed, even when the contact pressure to the electrode plate is not sufficient, the contact resistance can be reduced and the output can be improved.

  In the above, it is preferable that the flow path groove is formed by pressing, and the convex curved contact portion has a curved contact portion with a radius of curvature of 0.1 to 100 mm. By forming the flow path groove by press working, it becomes easy to form a curved surface contact portion with such a radius of curvature, and even if the contact pressure on the electrode plate is not sufficient when the radius of curvature is within the range, The contact resistance can be reduced more reliably and the output can be improved.

  Further, it is preferable that the metal plates on both sides are sealed by a bending press in a state where the peripheral edges are electrically insulated. According to this structure, the metal plate is sealed with a bending press in a state where the periphery of the metal plate is electrically insulated, so that each unit cell is reliably sealed without increasing the thickness while preventing short circuit between the two. It can be performed. Thereby, since rigidity is not required for the cell member, each unit cell can be significantly reduced in thickness.

  Moreover, it is preferable that the thickness of the said anode side metal plate is 0.05-1 mm. If the thickness is less than this range, the contact pressure against the electrode plate will be too small even if the rigidity improvement by pressing is taken into account.If the thickness is greater than this range, the purpose of weight reduction will be achieved. It is difficult to obtain a sufficient contact pressure on the contact surface without forming the curved contact portion.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is an assembled perspective view showing an example of a unit cell of the fuel cell of the present invention, and FIG. 2 is a longitudinal sectional view showing an example of a unit cell of the fuel cell of the present invention.

  As shown in FIGS. 1 to 2, the fuel cell of the present invention includes a plate-shaped solid polymer electrolyte 1, a cathode-side electrode plate 2 disposed on one side of the solid polymer electrolyte 1, and the other side. The anode side electrode plate 3 arranged, the cathode side metal plate 4 arranged on the surface of the cathode side electrode plate 2 and allowing the gas to flow to the inner surface side, and the surface of the anode side electrode plate 3 arranged on the inner surface side And an anode-side metal plate 5 that enables the fuel to flow through. In this embodiment, the cathode side metal plate 4 shows an example in which an opening 4c for naturally supplying air is formed.

  The solid polymer electrolyte 1 may be any solid polymer membrane battery as long as it is used in conventional solid polymer membrane batteries. From the viewpoint of chemical stability and conductivity, a perfluorocarbon having a sulfonic acid group which is a super strong acid. A cation exchange membrane made of a polymer is preferably used. Nafion (registered trademark) is preferably used as such a cation exchange membrane.

  In addition, for example, a porous film made of a fluororesin such as polytetrafluoroethylene impregnated with the above Nafion or other ion conductive material, a porous film made of a polyolefin resin such as polyethylene or polypropylene, or a non-woven fabric. A material carrying Nafion or another ion conductive material may be used.

  The thinner the solid polymer electrolyte 1 is, the more effective it is to make the whole thinner. However, in consideration of ion conduction function, strength, handling property, etc., 10 to 300 μm can be used, but 25 to 50 μm is preferable. .

  The electrode plates 2 and 3 can function as a gas diffusion layer, and can supply and discharge fuel gas, oxidizing gas, and water vapor, and at the same time can exhibit a current collecting function. As the electrode plates 2 and 3, the same or different ones can be used, and it is preferable to support a catalyst having an electrode catalytic action on the base material. The catalyst is preferably supported at least on the inner surfaces 2 b and 3 b in contact with the solid polymer electrolyte 1.

  As the electrode base material, for example, conductive carbon materials such as carbon paper, fibrous carbon such as carbon fiber nonwoven fabric, and aggregates of conductive polymer fibers can be used. In general, the electrode plates 2 and 3 are prepared by adding a water-repellent substance such as a fluororesin to such a conductive porous material. When the catalyst is supported, a catalyst such as platinum fine particles and fluorine It is formed by mixing a water-repellent substance such as a resin, mixing it with a solvent to form a paste or ink, and then applying this to one side of an electrode substrate that should face the solid polymer electrolyte membrane. The

  In general, the electrode plates 2 and 3 and the solid polymer electrolyte 1 are designed according to the reducing gas and the oxidizing gas supplied to the fuel cell. In the present invention, it is preferable to use air as the oxidizing gas and hydrogen gas as the reducing gas. In addition, methanol, dimethyl ether, or the like can be used instead of the reducing gas.

  For example, when hydrogen gas and air are used, the cathode-side electrode plate 2 on the side where air is naturally supplied causes a reaction between oxygen and hydrogen ions, so that water is generated. Is preferred. In particular, under the operating conditions of low operating temperature, high current density, and high gas utilization rate, the electrode porous body is likely to be clogged (flooded) due to the condensation of water vapor, particularly at the air electrode where water is generated. Therefore, in order to obtain stable characteristics of the fuel cell over a long period of time, it is effective to ensure the water repellency of the electrode so that the flooding phenomenon does not occur.

  As the catalyst, at least one metal selected from platinum, palladium, ruthenium, rhodium, silver, nickel, iron, copper, cobalt and molybdenum, or an oxide thereof can be used. A supported one can also be used.

  The thickness of the electrode plates 2 and 3 is more effective for reducing the overall thickness as the thickness is reduced, but is preferably 50 to 500 μm in view of electrode reaction, strength, handling properties, and the like.

  The electrode plates 2 and 3 and the solid polymer electrolyte 1 may be laminated and integrated in advance by adhesion, fusion, or the like, or may simply be arranged in a stacked manner. Such a laminated body can also be obtained as a thin film electrode assembly (MEA), and may be used.

  A cathode side metal plate 4 is disposed on the surface of the cathode side electrode plate 2, and an anode side metal plate 5 is disposed on the surface of the anode side electrode plate 3.

  The cathode side metal plate 4 is provided with an opening 4c for supplying oxygen in the air. As long as the cathode side electrode plate 2 can be exposed, the number, shape, size, formation position, and the like of the opening 4c may be any. However, in consideration of the supply efficiency of oxygen in the air and the current collection effect from the cathode side electrode plate 2, the area of the opening 4c is preferably 10 to 50% of the area of the cathode side electrode plate 2, In particular, 20 to 40% is preferable.

  The opening 4c of the cathode side metal plate 4 may be provided with a plurality of circular holes, slits, or the like regularly or randomly, or may be provided with a metal mesh.

  As the metal plates 4 and 5, any metal can be used as long as it does not adversely affect the electrode reaction, and examples thereof include stainless steel plates, nickel, copper, and copper alloys. However, from the viewpoints of elongation, weight, elastic modulus, strength, corrosion resistance, press workability, etc., a stainless steel plate, nickel and the like are preferable.

  In the present invention, as shown in FIG. 2, at least the inner surface of the anode side metal plate 5 is formed with a flow channel groove 9, and a convex curved contact portion 5r is formed between the flow channel grooves 9 formed in parallel. Is formed. In the present embodiment, an example is shown in which the anode side metal plate 5 is provided with a fuel injection port 5c and a discharge port 5d, and a channel groove 9 is provided between them by pressing.

  In the present invention, the shape of the curved contact portion 5r between the flow channel grooves 9 is not limited to the one having a circular cross section, but as shown in FIG. 3, when the cross section of the curved contact portion 5r is a circular arc, It is preferable that the curvature radius R of the inner surface is 0.1 to 100 mm, and it is more preferable that the curvature radius R of the inner surface is 0.1 to 10 mm. When the radius of curvature R is less than 0.1 mm, problems such as workability and durability are likely to occur. When the radius of curvature R exceeds 100 mm, the curved contact portion 5r approaches a flat surface, so that the contact pressure against the electrode plate is increased. If it is not sufficient, the contact resistance increases and the output tends to decrease.

  The channel groove 9 provided in the anode side metal plate 5 may have any planar shape or cross-sectional shape as long as the curved contact portion 5r as described above is formed. However, in consideration of the channel density, the lamination density at the time of lamination, the flexibility, etc., it is preferable to mainly form the vertical groove 9a parallel to one side of the metal plate 5 and the vertical groove 9b. In this embodiment, a plurality of (three in the illustrated example) vertical grooves 9a are connected in series to the horizontal grooves 9b to balance the flow path density and the flow path length.

  A part of the channel groove 9 (for example, the lateral groove 9 b) of the metal plate 5 may be formed on the outer surface of the electrode plate 3. As a method of forming the flow channel groove on the outer surface of the electrode plate 3, a mechanical method such as a hot press or cutting may be used. However, it is preferable to perform groove processing by laser irradiation in order to suitably perform fine processing. From the viewpoint of performing laser irradiation, the base material for the electrode plates 2 and 3 is preferably an aggregate of fibrous carbon.

  One or a plurality of inlets 5c and outlets 5d communicating with the channel groove 9 of the metal plate 5 can be formed. In addition, although the thickness of the metal plates 4 and 5 is effective for the whole thickness reduction, so that it is thin, from the reason mentioned above, 0.05-1 mm is preferable and 0.07-0.7 mm is more preferable.

  In the present invention, from the viewpoint of obtaining a reinforcing effect by forming the flow channel groove 9 while reducing the thickness by reducing the thickness of the metal plate 5, the flow channel groove 9 is formed by deformation of the metal plate 5 by press working. preferable. When the flow channel 9 is formed by press working, the flow channel 9 preferably has a width of 0.1 to 10 mm and a depth of 0.1 to 10 mm. The cross-sectional shape of the channel groove 9 is preferably substantially square, substantially trapezoidal, substantially semicircular, V-shaped or the like. It is also possible to form the flow channel 9 by etching or cutting, and in this case, it is preferable to form the flow channel 9 having the same width.

  Etching, punching, drilling, or the like is preferably used for forming the opening 4c in the metal plate 4, thinning the outer edges of the metal plates 4 and 5, and forming the inlet 5c and the like in the metal plate 5.

  In the present invention, a noble metal coating layer is preferably formed on at least one inner surface of the cathode side metal plate 4 or the anode side metal plate 5. The coating layer is not particularly limited as long as it prevents oxidation of the metal plates 4 and 5 and lowers the contact resistance with the electrode plates 2 and 3 such as carbon paper and the electrical extraction terminal. , Gold, platinum, palladium, ruthenium, and the like.

  The method for forming the coating layer of the noble metal is not particularly limited as long as it can be formed with good adhesion to the metal of the cell, and various types of forming methods can be used. As typical examples, plating, sputter deposition, ion plating, deposition, CVD, CAT-CVD, and the like can be used.

  In the present invention, the periphery of the metal plates 4 and 5 on both sides is sealed in an electrically insulated state. At that time, the periphery 1a of the solid polymer electrolyte 1 is removed from the electrode plates 2 and 3 on both sides. A structure in which the peripheral edge portion 1a is extended and held between the metal plates 4 and 5 opposed thereto is preferable. The sealing is preferably performed by mechanical sealing such as bending press, that is, so-called caulking.

  In the present embodiment, the peripheral portion 1 a of the solid polymer electrolyte 1 is sandwiched between the metal plates 4 and 5 with the insulating material 6 interposed therebetween, and the peripheral edge of the metal plates 4 and 5 is caulked with the insulating material 6 interposed. The example sealed by is shown. Electrical insulation can be performed by interposing the insulating material 6, the peripheral edge of the solid polymer electrolyte 1, or both.

  In the present invention, when caulking, as shown in FIG. 2, a structure in which the solid polymer electrolyte 1 is sandwiched between the outer edges of the metal plates 4 and 5 is preferable, and the solid polymer electrolyte 1 is sandwiched with the insulating material 6 interposed. More preferable is the structure. According to such a structure, inflow of gas or the like from one of the electrode plates 2 and 3 to the other can be effectively prevented. The thickness of the insulating material 6 is preferably 0.1 mm or less from the viewpoint of thinning. In addition, it is possible to further reduce the thickness by coating the insulating material (for example, the insulating material 6 can have a thickness of 1 μm).

  As the insulating material 6, a sheet-like resin, rubber, thermoplastic elastomer, ceramics, and the like can be used. However, in order to improve the sealing performance, resin, rubber, thermoplastic elastomer, and the like are preferable, and in particular, polypropylene, polyethylene, polyester, fluorine Resin and polyimide are preferable. The insulating material 6 can be integrated with the metal plates 4 and 5 in advance by sticking or coating the peripheral edges of the metal plates 4 and 5 directly or via an adhesive.

  As the caulking structure, the structure shown in FIG. 2 is preferable from the viewpoint of sealing performance, ease of manufacture, thickness, and the like. That is, the outer edge portion 5a of one metal plate 5 is made larger than the other outer edge portion 4a, and the insulating material 6 is interposed, while the outer edge portion 5a of one metal plate 5 is changed to the outer edge portion 4a of the other metal plate 4. A caulking structure that is folded back so as to sandwich pressure is preferable. In this caulking structure, it is preferable to provide a step in the outer edge portion 4a of the metal plate 4 by pressing or the like. Such a caulking structure itself is known as metal processing, and can be formed by a known caulking device.

  In the present invention, one or a plurality of unit cells as shown in FIG. 2 can be used. The unit cell is composed of a solid polymer electrolyte 1, a pair of electrode plates 2, 3, and a pair of metal plates 4, 5. It is also possible to stack a plurality of unit cells or arrange them on the same surface. By doing so, it is possible to provide a high-power fuel cell without the need to apply a certain pressure to the cell parts by mutually coupling with the fastening parts of the bolts and nuts.

  In use, a fuel supply tube can be directly joined to the fuel inlet 5c and the outlet 5d of the metal plate 5, but the thickness of the fuel cell is reduced in order to reduce the thickness of the fuel cell. A tube joint having a pipe parallel to the surface of the metal plate 5 is preferably provided.

  Since the fuel cell of the present invention can be thinned and can be designed to be small, light and free, it can be suitably used particularly for mobile devices such as mobile phones and notebook PCs.

[Other Embodiments]
(1) In the above-described embodiment, an example in which the caulking structure shown in FIG. 2 is adopted is shown. However, in the present invention, a caulking structure as shown in FIGS. 4A to 4B may be adopted.

  The crimped structure shown in FIG. 4A is a crimped structure in which the outer edge portions 4a and 5a of both the metal plates 4 and 5 are folded back. In this example, the metal plate 5 is not provided with a step portion, but the metal plate 4 is provided with a step portion. In this unit cell, a sealing member S is interposed between each of the metal plates 4 and 5 and the solid polymer electrolyte 1 so that the gas diffused from each of the electrode plates 2 and 3 is not mixed. .

  Further, the caulking structure shown in FIG. 4B is an insulating material that insulates each of the metal plates 4 and 5 by another metal plate 7 without folding the outer edge portions 4a and 5a of both the metal plates 4 and 5. It is the crimping structure clamped via 6a, 6b. In this example, the metal plate 4 and the metal plate 5 are provided with stepped portions that are gently inclined. In the caulking structure, both the metal plates 4 and 5 can be used as they are without being pressed.

  (2) In the above-described embodiment, an example in which the peripheral edges of the metal plates on both sides are electrically insulated and sealed by a bending press is shown, but in the present invention, the sealing method is not particularly limited, Mechanical sealing using fastening means such as rivets and bolts and nuts, or sealing by fusion of an adhesive or a sealing material may be used.

  (3) In the above-described embodiment, an example in which an opening for naturally supplying air to the cathode side metal plate is shown. However, as with the anode side metal plate, air or the like is obtained by etching or pressing. The oxygen-containing gas channel groove, inlet, and outlet may be formed. In that case, as with the anode side metal plate, power generation is performed while supplying air or the like from the inlet of the cathode side metal plate.

  (4) In the above-described embodiment, the cathode side electrode plate is exposed as it is from the opening of the cathode side metal plate. However, in the present invention, the cathode side metal plate is hydrophobic so as to cover the opening. A porous polymer porous membrane may be laminated. The polymer porous membrane may be laminated inside or outside the cathode side metal plate.

  The average pore diameter of the polymer porous membrane is preferably 0.01 to 3 μm in order to prevent water droplets from leaking while maintaining air permeability. The thickness of the polymer porous membrane is preferably 10 to 100 μm. Examples of the material for the polymer porous membrane include fluororesins such as polytetrafluoroethylene, polyolefins such as polypropylene and polyethylene, polyurethane, and silicone resins.

  Examples and the like specifically showing the configuration and effects of the present invention will be described below.

[Example 1]
Twenty-one grooves (width 0.5 mm, depth 0.2 mm, spacing 1.0 mm, radius of curvature of curved contact portion 0.2 mm) are provided by press working on corrosion-resistant SUS (50 mm x 26 mm x 0.1 mm thickness) It was. The obtained metal plate was gold-plated (plating thickness 0.3 μm) on the entire surface.
Then, an insulating sheet (50 mm × 26 mm × 2 mm width, thickness 80 μm) was bonded to SUS.

A thin film electrode assembly (49.3 mm × 25.3 mm) was prepared as follows. As the platinum catalyst, a 20% platinum-supported carbon catalyst (EC-20-PTC) manufactured by US Electrochem Co., Ltd. was used. The platinum catalyst, carbon black (Akzo Ketjen Black EC), and polyvinylidene fluoride (Kayner) were mixed at a ratio of 75% by weight, 15% by weight, and 10% by weight, respectively, and dimethylformamide was added by 2.5% by weight. The catalyst paste was prepared by adding to the mixture of the platinum catalyst, carbon black, and polyvinylidene fluoride in such a ratio as to give a% polyvinylidene fluoride solution, and dissolving and mixing in a mortar. Carbon paper (TGP-H-90 manufactured by Toray, thickness 370 μm) is cut into 20 mm × 43 mm, and about 20 mg of the catalyst paste prepared as described above is applied with a spatula and heated at 80 ° C. Dried in the dryer. Thus, a carbon paper carrying 4 mg of the catalyst composition was produced. The amount of platinum supported is 0.6 mg / cm ² .

  Using the platinum catalyst-supported carbon paper produced as described above and a Nafion film (Nafion 112 manufactured by DuPont) (25.3 mm × 49.3 mm, thickness 50 μm) as a solid polymer electrolyte (cation exchange membrane), On both sides, hot pressing was performed for 2 minutes using a mold at 135 ° C. and 2 MPa. The thin-film electrode assembly thus obtained is sandwiched between the two SUS plates in the center and crimped as shown in FIG. 2 to obtain a thin and small micro fuel cell having an outer dimension of 50 mm × 26 mm × 1.4 mm. I was able to do things. In addition, the mass of the whole cell was 2.72g.

  The battery characteristics of the micro fuel cell were evaluated. The fuel cell characteristics were evaluated using a fuel cell evaluation system manufactured by Toyo Technica at room temperature using pure hydrogen gas and pure oxygen gas. The gas flow rate was 0.2 L / min. A graph showing the relationship between current density and voltage at that time is shown in FIG. 5, and a graph showing the relationship between current density and cell resistance is shown in FIG.

[Comparative Example 1]
In Example 1, when producing a cathode side metal plate and an anode side metal plate, a metal plate having a thickness of 0.3 mm was used to etch only the inner surface, and a width of 0. A fuel cell was produced in the same manner as in Example 1 except that a 5 mm flat contact portion was formed, and evaluated in the same manner. The results are also shown in FIGS. As is clear from this graph, the thickness of the metal plate increased and the contact pressure increased, so the battery characteristics were the same as in Example 1. However, the mass of the entire cell was greatly increased to 4.65 g. This is a problem in reducing weight.

[Comparative Example 2]
In Example 1, when producing the cathode side metal plate and the anode side metal plate, the inner surface and the outer surface were formed using a metal plate having a thickness of 0.3 mm so that the mass of the entire cell was the same as in Example 1. A fuel cell was fabricated in exactly the same manner as in Example 1, except that a plane contact portion having a width of 0.5 mm was formed between the parallel channel grooves with the same concavo-convex shape as in Example 1 by etching. Then, the evaluation was performed in the same manner. The results are also shown in FIGS. As apparent from this graph, the bending rigidity of the metal plate was lowered and the contact pressure was lowered, so that the cell resistance was increased by the flat contact portion, and the battery characteristics were greatly deteriorated as compared with Example 1. In addition, the mass of the whole cell was 2.81g.

Assembly perspective view showing an example of the fuel cell (unit cell) of the present invention The longitudinal cross-sectional view which shows an example of the fuel cell (unit cell) of this invention Sectional drawing which shows the principal part of an example of the fuel cell (unit cell) of this invention Sectional drawing of the principal part which shows the other example of the crimping structure in the fuel cell of this invention The graph which shows the relationship between the current density and voltage of the fuel cell obtained by the Example of this invention, etc. The graph which shows the relationship between the current density and cell resistance of the fuel cell obtained by the Example of this invention, etc. Assembly perspective view showing an example of a conventional fuel cell

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Solid polymer electrolyte 2 Cathode side electrode plate 2a Peripheral part of cathode side electrode plate 3 Anode side electrode plate 3a Peripheral part of anode side electrode plate 4 Cathode side metal plate 4c Opening part 5 Anode side metal plate 5c Inlet 5d Outlet 5r Curved surface contact portion 6 Insulating material 9 Channel groove R Curvature radius of the inner surface of curved surface contact portion

Claims (4)

A plate-shaped solid polymer electrolyte, a cathode side electrode plate disposed on one side of the solid polymer electrolyte, an anode side electrode plate disposed on the other side, and an inner surface disposed on the surface of the cathode side electrode plate A fuel cell comprising: a cathode-side metal plate that allows gas to flow to the side; and an anode-side metal plate that is disposed on the surface of the anode-side electrode plate and allows fuel to flow to the inner surface side. ,
The peripheral edges of the metal plates on both sides are sealed in an electrically insulated state, and at least the inner surface of the anode side metal plate is formed with a flow channel groove, and the flow channel grooves formed in parallel are formed. A fuel cell having a convex curved contact portion formed therebetween.   2. The fuel cell according to claim 1, wherein the flow path groove is formed by pressing, and the convex curved contact portion forms a curved contact portion having a radius of curvature of 0.1 to 100 mm.   The fuel cell according to claim 1, wherein the metal plates on both sides are sealed by a bending press in a state where the peripheral edges of the metal plates are electrically insulated.   The fuel cell according to any one of claims 1 to 3, wherein the anode side metal plate has a thickness of 0.05 to 1 mm.

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