JP5713343B2 - Fuel cell and manufacturing method thereof - Google Patents

Description

  The present invention relates to a fuel cell and a method for manufacturing the same, and more particularly to a fuel cell having an integrated thin structure.

  In recent years, along with the portability, miniaturization, and high performance of various electric devices, there is an increasing demand for improving the performance of small batteries that serve as power sources. In addition, with these developments, further thinning of the battery is required. On the other hand, as a battery suitable for miniaturization, in particular, a polymer electrolyte fuel cell is used, and various research and development are underway. Conventional polymer fuel cells generally have a seven-layer structure of a fuel channel (separator), a diffusion layer, a catalyst layer, a polymer electrolyte membrane, a catalyst layer, a diffusion layer, and a fuel channel (separator). Many. Further, in a conventional polymer fuel cell, a powdered catalyst in which fine platinum particles are supported on the surface of carbon powder is used for the catalyst layer. However, in order to reduce the electrical contact resistance between components, such as a catalyst powder-electrolyte membrane manufactured in a separate process, in this type of conventional fuel cell in response to the demand for further thinning, It is necessary to tighten the fuel cell sandwiched between the pair of separators with a strong force. For this reason, it is said that there is a limit in reducing the thickness of a conventional polymer battery from the viewpoint of the strength of the fuel flow path.

  On the other hand, an electrode structure for a fuel cell using metal-supported porous silicon has been proposed as a structure used for a fuel cell capable of being miniaturized and capable of high output (see Patent Document 1 below). In addition, a membrane electrode assembly has been proposed that is less likely to be damaged during production or battery operation as compared with the prior art.

JP 2007-119897 A JP 2008-98070 A S. Mohghdam, E .; Pengwang, Y. et al. B. Jiang, A .; R. Garcia, D .; J. et al. Burnett, C.I. J. et al. Brinker, R.A. I. Masel, M .; A. Shannon et al., Nature Nanotechnology, 5, 210 (2010).

  In the electrode structure for a fuel cell using metal-supporting porous silicon described in Patent Document 1, a silicon substrate having a porous layer on one surface is immersed in a plating solution, and a metal is applied to the porous layer of the silicon substrate. Is deposited to form a catalyst layer. According to such an electrode structure, a fuel cell having a thickness of 300 μm or less can be formed by sandwiching a polymer electrolyte membrane (Polymer Electrolyte Membrane) between the electrode structures.

On the other hand, for manufacturing the metal-supporting porous silicon, MEMS (Micro Electro Mechanical Systems) technology can be used. Here, the MEMS technology refers to a technology for manufacturing a microstructure having a mechanical function and an electrical function by using a semiconductor manufacturing process or a microfabrication process used in a semiconductor integrated circuit or the like. .
However, in order to produce a fuel cell using the electrode structure, a process of bonding the polymer electrolyte membrane and the electrode structure is required. Such a bonding process is an independent process from the process by the MEMS technique, and furthermore, it is difficult to manage the adhesion state at the time of bonding.

  In addition, the membrane electrode assembly described in Patent Document 2 has an electrolyte membrane in which pores of a porous membrane are filled with an electrolyte polymer, and an anode electrode is joined to one surface and a cathode electrode is joined to the other surface. At least one of the electrodes is formed using MEMS technology.

  However, even when the above electrolyte membrane is used, it is necessary to bond the electrolyte membrane and the electrode, and the same problems as in the fuel cell using the electrode structure occur.

  Non-Patent Document 1 reports an example in which a proton exchange membrane made of porous silicon is used as an electrolyte layer of a fuel cell. However, in Non-Patent Document 1, the catalyst layer is formed by applying a catalyst such as platinum on the silicon surface. When the catalyst layer is provided by means such as coating, it is difficult to manage the interface between the electrolyte layer and the catalyst layer and to ensure electrical conduction, and there is room for improvement from the viewpoint of electrical resistance between the catalysts. is there.

  In view of the above-described facts, an object of the present invention is to provide a fuel cell that is high in productivity and yield, and that can be thinned, and a method for manufacturing the fuel cell.

<1> has a porous region, and a silicon region provided around the porous region, and, on the porous region, a first porous metal area catalytic metal is supported, porous A silicon substrate comprising in this order a proton conducting region and a second porous metal region on which a catalytic metal is supported;
A first current collecting layer joined to the first porous metal region on one surface of the silicon substrate, and a second current joined to the second porous metal region on the other surface of the silicon substrate. A current collecting layer, an insulating layer provided on one surface of the silicon substrate,
Equipped with a,
At least one of the first porous metal region and the first current collecting layer, the second porous metal region and the second current collecting layer, and the silicon substrate. Electrically isolated from the silicon region,
The portion composed of the first porous metal region and the first current collecting layer and the portion composed of the second porous metal region and the second current collecting layer are insulated via the insulating layer. This is a fuel cell.

  The fuel cell of the present invention uses a silicon substrate that includes first and second porous metal regions and a porous proton conducting region, and in which a catalyst layer and an electrolyte layer are integrally formed. This eliminates the need for a step of attaching a catalyst layer or the like to the polymer electrolyte membrane or the like, so that the reliability of the product is high and the manufacturing process can be simplified. Further, in the fuel cell of the present invention, since the catalyst layer is formed by the porous metal region formed in the porous region of the silicon substrate, it is compared with the polymer electrolyte fuel cell using a powder catalyst. Thus, the fuel cell itself can be easily thinned.

<2> and the porous region, and the silicon region provided around the porous region, and the insulating layer forming step of forming an insulating layer on one surface of the silicon substrate to have a,
A silicon substrate having a porous proton conductive region in the porous region is immersed in a plating solution, and a catalytic metal is deposited in the porous region, and a first porous metal is formed on each side of the porous proton conductive region. A porous metal region forming step of forming the region and the second porous metal region ;
A current collecting layer forming step of forming a first current collecting layer joined to the first porous metal region and a second current collecting layer joined to the second porous metal region, Current collection layer formation for forming the first current collection layer and the second current collection layer so that the first current collection layer and the second current collection layer are insulated via the insulating layer Process,
The method for producing a fuel cell according to <1> , including:

  The method for producing a fuel cell of the present invention (hereinafter sometimes simply referred to as “the production method of the present invention”) includes a porous metal region step of forming a porous metal region on a silicon substrate having a porous proton conducting region. By including the catalyst region (porous metal region) and the proton conducting region can be integrally formed in the porous region of the silicon substrate.

<3> the insulating layer forming step, the one surface of the silicon substrate, a step of forming the insulating layer so as to overlap the porous region and partially the porous metal region forming step, the a method for manufacturing a fuel cell of the <2> is a step of forming the first and second porous metal region in the silicon substrate in which an insulating layer is formed.

  According to the manufacturing method of the present invention, before forming the porous metal region, the insulating layer is formed so as to partially overlap (cover) the porous region, so that the porous metal region is formed in the porous metal region forming step. In forming the porous metal region, the first or second porous metal region can be formed so as to be isolated from the silicon region of the silicon substrate.

  As described above, according to the present invention, it is possible to provide a fuel cell that has high productivity and a high yield and can be thinned, and a method for manufacturing the fuel cell.

It is sectional drawing which shows one Embodiment of the fuel cell of this invention. It is the schematic which shows the porous area | region of a silicon substrate. It is explanatory drawing which shows one Embodiment of the structure which laminated | stacked the fuel cell of this invention. It is explanatory drawing which shows one Embodiment of the manufacturing process of the fuel cell of this invention. It is a graph which shows the voltage of the cell which concerns on an Example, a current density, and an output density characteristic.

"Fuel cell"
The fuel cell of the present invention has a porous region and a silicon region, and the porous region includes a first porous metal region in which a catalytic metal is supported, a porous proton conducting region, and a catalytic metal. A silicon substrate provided with a supported second porous metal region in this order; a first current collecting layer bonded to the first porous metal region on one surface of the silicon substrate; And a second current collecting layer bonded to the second porous metal region on the other surface of the silicon substrate. Here, the “porous region” of the silicon substrate means a region where a plurality of pores are formed in the silicon substrate. On the other hand, the “silicon region” of the silicon substrate means a portion where no pore is provided in the silicon substrate, that is, a non-porous region. However, the fuel cell according to the following embodiment has a porous region and a silicon region provided around the porous region, and the porous region has a first catalyst metal supported thereon. A porous silicon region, a porous proton conducting region, and a second porous metal region on which a catalytic metal is supported in this order, and a silicon substrate on one surface of the silicon substrate. A first current collecting layer bonded to one porous metal region; a second current collecting layer bonded to the second porous metal region on the other surface of the silicon substrate; and one of the silicon substrates. And an insulating layer provided on the surface. Further, at least one of the first porous metal region and the portion comprising the first current collecting layer, and the portion comprising the second porous metal region and the second current collecting layer, and The silicon region of the silicon substrate is electrically isolated from the first porous metal region and the first current collecting layer, and the second porous metal region and the second current collecting layer. It is assumed that a portion made of an electric layer is insulated through the insulating layer.

  Hereinafter, an embodiment of a fuel cell of the present invention will be described with reference to FIG. FIG. 1 is a cross-sectional view showing an embodiment of a fuel cell of the present invention. In FIG. 1, the fuel cell 100 is composed of a silicon substrate 2, an insulating layer 10, a current collecting layer 12, and a current collecting layer 14.

(Silicon base)
As shown in FIG. 1, a silicon region (non-porous region) 3 and a porous region 4 are formed in the silicon substrate 2. As the silicon substrate 2, a commercially available silicon wafer can be used without any limitation regardless of n-type and p-type. For example, n-type silicon is preferably used from the viewpoint of relatively high etching rate. it can. Further, from the viewpoint of controlling the pore diameter of the porous region, highly doped n-type silicon having a low resistivity can be used. The resistivity is preferably 0.1Ω or less, and more preferably 0.02Ω or less.

The thickness of the silicon substrate 2 is not particularly limited, but is preferably 200 μm or less, more preferably 150 μm or less, and particularly preferably 100 μm or less from the viewpoint of forming a porous region.
On the other hand, from the viewpoint of the strength of the substrate and the fuel permeability, it is preferably 10 μm or more, more preferably 20 μm or more, and particularly preferably 50 μm or more.

(Porous region)
The porous region 4 of the silicon substrate 2 is provided with a plurality of pores. The shape of the pores of the porous region 4 is not particularly limited. For example, when the porous region is formed by anodizing the silicon substrate 2 as described later, one of the silicon substrates 2 is formed. A plurality of through holes penetrating from one surface to the other surface can be formed. The through holes provided in the porous region 4 will be described with reference to FIG. FIG. 2 is a schematic view showing the porous region of the silicon substrate. As shown in FIG. 2, the porous region 4 is provided with a plurality of through holes 16 relating to one surface of the silicon substrate 2 to the other surface. As shown in FIG. 2, the through-hole 16 is provided substantially in parallel with the thickness direction of the silicon substrate 2 (arrow A in FIGS. 1 and 2). The through-hole 16 may penetrate, for example, substantially perpendicular to the film surface, may penetrate through the film surface at an angle of less than 90 °, meander, zigzag, etc. , May penetrate at random. In addition to the through holes 16, non-through holes may exist as the pores provided in the porous region 4. A specific method for forming the porous region will be described later.

  The number of pores provided in the porous region 4, the cross-sectional shape, the average pore diameter, and the like are not particularly limited, and can be appropriately selected in accordance with the formation of the porous proton conductive region described later. For example, examples of the cross-sectional shape of the pore include a circle, an ellipse, a polygon, a shape in which these are connected, and a combination thereof. The average pore diameter of the pores is preferably 11 nm to 10 μm, and more preferably 100 nm to 1 μm, when the electrolyte is filled. In the case of chemical modification with a molecule having an acidic group at the end, 0.5 nm to 1 μm is preferable, and 5 nm to 50 nm is more preferable. In addition, the pore diameter can be changed by placing in the porous region.

  As the ratio (porosity) of the pores of the porous region 4 to the silicon substrate 2 (the total of the silicon region 3 and the porous region 4), the viewpoint of the balance between the electrolyte group amount per unit area and the film strength Therefore, the upper limit is preferably 95% or less, more preferably 90% or less, particularly preferably 85% or less, and most preferably 80% or less. Further, the lower limit is preferably 5% or more, more preferably 10% or more, particularly preferably 15% or more, and further preferably 20% or more.

The porosity can be obtained by measuring the volume and weight of the silicon substrate 2 and calculating the proportion of air in the total volume from the specific gravity of the constituent material.
Specifically, it can be obtained by the following equation.
Porosity% = (volume of silicon substrate 2−weight of silicon substrate 2 / specific gravity of silicon constituting silicon substrate 2) / (volume of silicon substrate 2) × 100

  As shown in FIG. 1, a porous proton conducting region 6 and porous metal regions 8A and 8B are formed in the porous region 4, and these form an electrolyte layer and a catalyst layer. As described above, the porous proton conductive region 6 and the porous metal regions 8A and 8B adjacent to the porous proton conductive region 6 are integrally formed on the silicon substrate 2. For this reason, in the manufacture of the fuel cell 100 of the present embodiment, it is not necessary to attach a polymer electrolyte membrane or the like where positional accuracy is important, and a highly reliable thin fuel cell is manufactured in a simple process. can do.

(Porous proton conduction region)
The porous proton conductive region 6 is a region in the porous region 4 in which the electrolyte body is filled or modified with a molecule having a sulfonic acid group at its terminal and serves as an electrolyte layer (proton conductive layer). Are provided with porous metal regions 8A and 8B. The porous proton conductive region 6 is formed by, for example, filling an electrolyte body into a plurality of pores in the porous region 4 or modifying the pores with molecules having a sulfonic acid group at the terminal. be able to.

  When the porous proton conductive region 6 is formed by filling the pores with an electrolyte, an electrolyte polymer having proton conductivity can be used as the electrolyte. Specific examples of the electrolyte polymer include a polymer having one or more electrolyte groups in the main chain and / or side chain, a polymer containing an electrolyte such as an acid and a room temperature molten salt, and the like. be able to. Moreover, these polymers may be contained in one kind or two or more kinds. Furthermore, these polymers may be cross-linked as necessary.

  In addition, the electrolyte polymer may exist as a polymer before being filled in the pores, or after the polymer precursor capable of generating the electrolyte polymer is filled in the pores, the polymer is polymerized and crosslinked. Etc. may be used to form an electrolyte polymer.

  Examples of the electrolyte group contained in the electrolyte polymer include acidic groups such as a sulfonic acid group, a sulfonimide group, a phosphonic acid group, a phosphonous acid group, and a carboxylic acid group, and high proton conductivity is easily obtained. From this viewpoint, a sulfonic acid group is preferable. Moreover, 1 type, or 2 or more types of these electrolyte groups may be contained.

  Examples of the electrolyte polymer include fluorinated all or part of the polymer skeleton, such as perfluorocarbon sulfonic acid polymers such as Nafion (registered trademark), perfluorocarbon phosphonic acid polymers, and trifluorostyrene sulfonic acid polymers. Fluoropolymers that have electrolyte groups; such as polysulfone sulfonic acid, polyaryl ether ketone sulfonic acid, polybenzimidazole alkyl sulfonic acid, polybenzimidazole alkyl phosphonic acid, etc. A polymer having an electrolyte group; a monomer having an electrolyte group; a monomer having a functional group that can be converted into an electrolyte group; and a monomer having a site capable of introducing an electrolyte group before and after polymerization. An electrolyte monomer consisting etc. may be mentioned polymers having a monomer unit. Moreover, 1 type, or 2 or more types may be contained for these electrolyte polymers.

Examples of the monomer having an electrolyte group include 2- (meth) acrylamide-2-methylpropanesulfonic acid, 2- (meth) acrylamide-2-methylpropanephosphonic acid, styrenesulfonic acid, (meth) allylsulfonic acid, Examples thereof include vinyl sulfonic acid, isoprene sulfonic acid, (meth) acrylic acid, maleic acid, crotonic acid, vinyl phosphonic acid, acidic phosphoric acid group-containing (meth) acrylate and the like. The electrolyte monomer is preferably a vinyl compound having a sulfonic acid group or a vinyl compound having a phosphoric acid group from the viewpoint of excellent proton conductivity, and more preferably 2 from the viewpoint of having high polymerizability. -(Meth) acrylamido-2-methylpropanesulfonic acid and the like.
“(Meth) acryl” means “acryl and / or methacryl”, “(meth) allyl” means “allyl and / or methallyl”, and “(meth) acrylate” means “acrylate and / or methacrylate”. Means.

  Examples of the monomer having a functional group that can be converted into an electrolyte group before and after the polymerization include salts, anhydrides, esters, and the like of the compound. In addition, when the acid residue of the monomer used is a derivative such as a salt, an anhydride, or an ester, proton conductivity can be imparted by forming a protonic acid type after polymerization.

  Examples of the monomer having a site capable of introducing an electrolyte group before and after the polymerization include monomers having a benzene ring such as styrene, α-methylstyrene, chloromethylstyrene, and t-butylstyrene. Specific examples of the method of introducing an electrolyte group into these monomers include a method of sulfonation with a sulfonating agent such as chlorosulfonic acid, concentrated sulfuric acid, and sulfur trioxide.

  It is preferable that substantially all of the pores of the porous proton conductive region 6 are filled in the electrolyte polymer from the viewpoint of obtaining high proton conductivity. However, not all the pores need to be filled with an electrolyte polymer, and pores not filled with an electrolyte polymer may be used as long as they do not adversely affect ion conductivity, fuel permeability, and the like. May be partially present.

  The porous proton conductive region 6 can also be formed by modifying the inside of the pore with a molecule having a sulfonic acid group at the terminal. A method of modifying the inside of the pores with a molecule having a sulfonic acid group at the end will be described later.

(Porous metal region)
The porous metal regions 8A and 8B are regions in which the catalyst metal is supported in the porous region 4, and serve as a catalyst layer. In the porous metal regions 8A and 8B, the catalyst metal may be supported on the pore surface, or the catalyst metal itself may form a porous structure.

  The method for supporting the catalyst metal is not particularly limited, but a configuration in which the catalyst metal is supported on the pore surface by plating is preferable. For example, in the porous metal regions 8A and 8B, as described later, the silicon substrate 2 on which the porous region 4 is formed is immersed in a plating solution in which a water-soluble salt containing a catalyst metal such as platinum is dissolved in water. Can be formed.

  The catalyst metal may be distributed throughout the porous metal regions 8A and 8B. Further, the boundary between the porous metal regions 8A and 8B and the porous proton conducting region 6 does not need to be clearly separated, and the amount of metal increases from the porous proton conducting region 6 side toward the surface of the silicon substrate 2. Such a continuous distribution may be used.

The upper limit of the content of the catalyst metal in the porous metal area 8A or 8B, preferably 10 mg / cm ² or less, 5 mg / cm ² or less is more preferred. This is because if the content of the catalyst metal is too large, the particle size of the catalyst metal such as platinum becomes large and the utilization efficiency per weight of the catalyst metal tends to decrease. On the other hand, the lower limit of the catalyst content, in terms of maintaining performance, preferably 0.01 mg / cm ² or more, 0.1 mg / cm ² is more preferable.

  Specific examples of the catalyst metal include noble metals such as platinum, platinum-ruthenium alloy, palladium, platinum-palladium alloy, platinum-cobalt alloy, and platinum-iron alloy, and noble metal alloys. The catalyst metal may be used alone or in combination of two or more.

  Moreover, as a catalyst metal of the porous metal area | region provided in the cathode side, platinum etc. can be used suitably, for example. On the other hand, as the catalyst metal in the porous metal region provided on the anode side, for example, a platinum-ruthenium alloy that can easily reduce the poisoning of the catalyst by carbon monoxide can be preferably used.

  Further, as shown in FIG. 1, in the fuel cell 100, the first porous metal region 8 </ b> A is configured not to contact the silicon region 3. As described above, the first porous metal region 8A and the silicon region 3 are separated from each other, so that the first porous metal region 8A and the second porous metal region 8B are interposed via the silicon region 3. Can be electrically insulated. Thereby, it can prevent that porous metal area | regions contact electrically via a silicon | silicone area | region, and can prevent the fall of the electric power generation amount of the fuel cell 100, etc. In the present embodiment, the first porous metal region 8A is configured not to contact (isolate) the silicon region 3, but the present invention is not limited to this, and at least the first porous metal region 8A is not limited to this. By isolating either one of the porous metal region 8A and the second porous metal region 8B from the silicon region 3 (non-porous region) of the silicon base, the porous metal regions are electrically connected to each other. Can be insulated.

(Insulating layer)
In FIG. 1, an insulating layer 10 is provided on the side of the silicon substrate 2 where the first porous metal region 8A is formed. In the fuel cell 100, the insulating layer 10 is provided on the surface of the silicon substrate 2, and the first porous metal region 8A on the side where the first porous metal region 8A of the silicon substrate 2 is provided is provided. It is formed in a layered form in the area that is not. In addition, a current collecting layer 12 is provided on the insulating layer 10. The insulating layer 10 serves to suppress the porous metal regions 8 </ b> A and 8 </ b> B and the current collecting layer 12 and the current collecting layer 14 from being electrically joined via the silicon region 3. As the material of the insulating layer, a known organic or inorganic insulating material that can be thinned can be appropriately used. As the organic insulating material, for example, a paraxylylene-based polymer such as Parylene (registered trademark) can be used. The paraxylylene-based polymer has a structure in which benzene rings are connected via CH ₂ , and the polymerized paraxylylene is a highly stable polymer having a molecular weight of 500,000. Paraxylylene-based polymers are superior in insulation properties, barrier properties, and chemical resistance due to their high stability, and can be deposited at room temperature by chemical vapor deposition (CVD).・ Used in various fields such as protection of automobiles, electronics and cultural properties. As the paraxylylene-based polymer, for example, commercially available dix-C (dichloroparacyclophane) manufactured by Daisan Kasei Co., Ltd.) can be used. The fuel cell 100 in FIG. 1 forms an insulating layer 10 made of a paraxylylene-based polymer film on an arbitrary portion on the silicon substrate 2 to insulate the porous metal regions 8A and 8B formed on both surfaces of the substrate. Can be done. In addition, a silicon nitride film can be used as the inorganic insulating material.

  The thickness of the insulating layer 10 is not particularly limited, but is preferably 5 nm to 10 μm, more preferably 10 nm to 1 μm, from the viewpoint of film strength and manufacturing efficiency.

(Collector layer)
The current collecting layers 12 and 14 have a role of moving electrons generated in the porous metal region 8A or 8B to the other porous metal region and supply a current generated by the fuel cell 100 to the outside of the cell. Fulfill. The first current collecting layer 12 is formed on one surface of the silicon substrate 2 (upper side in the drawing in FIG. 1) so as to be bonded to the first porous metal region 8A. The second current collecting layer 14 is formed on the other surface of the silicon substrate 2 so as to be joined to the second porous metal region 8B. Further, although not particularly limited, if the contact area between the end of the current collecting layer 12 or the current collecting layer 14 shown in FIG. This is advantageous.

  Specific examples of the material forming the current collecting layers 12 and 14 include copper, silver, gold, platinum, palladium, alloys thereof, and stainless steel. These may be contained alone or in combination of two or more. Moreover, the thickness of the current collection layers 12 and 14 is not specifically limited, It can set suitably in consideration of weight reduction or an electrical resistance. The thickness of the current collecting layers 12 and 14 is preferably thick from the viewpoint of strength and electrical resistance, but is preferably 1 μm or less in consideration of cost and productivity.

(Slave)
In FIG. 1, the silicon substrate 2 has a recess on the first porous metal region 8 </ b> A side, and forms a groove 15. The groove 15 serves as a fuel supply path as a flow path for an oxidant such as oxygen, a fuel gas such as hydrogen, and a liquid such as methanol. The fuel cell 100 has a shape in which the groove 15 is provided only on one side, but the present invention is not limited to this, and has a shape in which the groove is provided on both surfaces of the silicon substrate 2. It may be. As described above, the fuel cell 100 can be integrally formed up to the fuel flow path by providing the groove serving as the gas or fluid flow path on at least one surface of the silicon substrate 2. Further, the shape of the flow path of the groove 15 is not particularly limited as long as fuel or an oxidant can be supplied, and a serpentine shape (single serpentine, multi serpentine shape, etc.) often used for a fuel cell separator, It may be a spiral shape. Further, the width of the recess, the groove depth of the recess, etc. are not particularly limited, and the flow rate of the oxidizing agent such as air and fuel, according to the shape, size and required battery performance of the power generation part, What is necessary is just to design in consideration of the flow velocity.

(Power generation mechanism)
Next, the case where hydrogen-containing fuel is supplied from the first porous metal region 8A side and air (oxygen) is supplied from the second porous metal region 8B side will be described for the power generation mechanism of the fuel cell 100. When the hydrogen-containing fuel is supplied to the groove 15, the hydrogen-containing fuel enters the first porous metal region 8 A, and the hydrogen molecules are converted into electrons by the action of a catalyst such as platinum supported on the porous region 4. And hydrogen ions (H ⁺ ). The electrons move to the current collecting layer 14 via an external conductor (not shown) joined to the current collecting layer 12, and a current is generated. On the other hand, hydrogen ions (H ⁺ ) generated in the first porous metal region 8A move to the second porous metal region 8B through the porous proton conductive region 6. Next, the hydrogen ions (H ⁺ ) that have moved from the first porous metal region 8A combine with oxygen that has entered the second porous metal region 8B and the electrons that have moved through the external conductor to form water. (H ₂ O).

(Other embodiments)
The fuel cell of the present invention may be used alone, or a plurality of fuel cells may be stacked and used as shown in FIG. FIG. 3 is an explanatory view showing an embodiment of a configuration in which the fuel cells of the present invention are stacked. FIG. 3 shows a stack structure 18 in which a plurality of fuel cells (fuel cells 100A to 100F) are stacked. Conductive wire 20 is joined to the anode side (side to which hydrogen is supplied) of each of fuel cells 100A to 100F, and is joined to the negative electrode (negative electrode). The fuel cells 100A to 100F are connected to each other through a conductive wire 20 joined to the anode side. On the other hand, the conducting wire 22 is joined to the cathode side (side to which oxygen is supplied) of each of the fuel cells 100A to 100F, and joined to the + electrode (positive electrode). Moreover, each fuel cell 100A-F is connected via the conducting wire 22 joined to the cathode side. Such a stack structure 18 supplies hydrogen-containing fuel to the anode-side grooves of the fuel cells 100A to 100F, and supplies oxygen-containing gas to the cathode-side grooves of the fuel cells 100A to 100F. A current is generated by the same operation as that of the fuel battery cell 100 described above.

  Although FIG. 3 shows a stack structure in which fuel cells 100A to 100F are simply stacked and hydrogen or oxygen is alternately supplied to each layer, the present invention is not limited to this structure. A serially coupled stack structure can also be configured by interposing an insulating layer in the substrate.

<< Method for Manufacturing Fuel Cell of the Present Invention >>
In the production method of the present invention, a silicon substrate having a porous region and a silicon region, and having a porous proton conductive region in the porous region is immersed in a plating solution, and a catalytic metal is deposited in the porous region. And a porous metal region forming step of forming a first porous metal region and a second porous metal region on both sides of the porous proton conducting region, respectively. Moreover, the manufacturing method of this invention may provide a groove formation process, an insulating layer formation process, a current collection layer formation process, etc. as needed. However, the method for manufacturing a fuel cell according to the following embodiment is an insulating layer formation in which an insulating layer is formed on one surface of a silicon substrate having a porous region and a silicon region provided around the porous region. And a step of immersing a silicon substrate having a porous proton conductive region in the porous region in a plating solution, depositing a catalytic metal in the porous region, and forming a first on each side of the porous proton conductive region. A porous metal region forming step for forming a porous metal region and a second porous metal region, a first current collecting layer joined to the first porous metal region, and the second porous metal region A current collecting layer forming step of forming a second current collecting layer to be bonded to the first current collecting layer, wherein the first current collecting layer and the second current collecting layer are insulated via the insulating layer Forming the first current collecting layer and the second current collecting layer And that collector layer forming step, is intended to include.
Furthermore, in the production method of the present invention, a silicon substrate having a porous region and a porous proton conducting region and a silicon region prepared in advance can be used. Furthermore, these silicon substrates can be manufactured, for example, by a method for manufacturing a silicon substrate having a porous forming step and a proton conductive region forming step described later. Moreover, the silicon substrate manufacturing method and the fuel cell manufacturing method of the present invention described later may be performed separately or continuously. For this reason, in the method for producing a fuel cell of the present invention, a porous base region and a proton conductive region forming step, which will be described later, are provided to form a silicon substrate having a porous region and the like, and further a porous metal region forming step is performed. May be.

<Manufacturing method of silicon substrate>
(Porous forming process)
The porous forming step is a step of forming a porous region in the silicon substrate. Specifically, in the porous step, the porous region is formed by making the target region of the silicon substrate porous, for example, from the surface of the substrate to the other surface in the thickness direction of the silicon substrate. . The method for making a part of the silicon substrate porous is not particularly limited, and examples thereof include a method of forming a porous region in the silicon substrate by etching. The etching is not limited by either wet or dry etching, and examples thereof include an anodizing treatment using an anodizing solution. The pore size and shape of the porous region, layer thickness, etc., adjust the parameters such as resistivity of silicon single crystal to be used, current density during anodic oxidation, anodic oxidation time, liquid composition of anodic oxidation liquid, concentration, liquid temperature, etc. It is possible to control by doing.

The upper limit of the current density at the time of anodization is preferably 10,000 A / m ² or less, more preferably 5000 A / m ² or less, and more preferably 2000 A / m ² from the viewpoints that electropolishing is less likely to be promoted and porosity is easily promoted. The following are particularly preferred: The lower limit of the current density during the anodization, in view of too porosity decreases, 1A / ^{m 2} or more is preferable, 100A / ^{m 2} or more is more preferable, 500A / ^{m 2} or more and particularly preferable.

Examples of the anodic oxidation solution include one or more compounds that can be dissolved in water, alcohol, or the like, such as hydrofluoric acid, sodium fluoride, or ammonium fluoride, to generate fluorine ions. A liquid dissolved in a solvent can be mentioned. The concentration of fluoride ions in the anodizing liquid is ^{usually, 0.5mol / dm 3 ~25mol / dm} 3 approximately.

  The liquid temperature of the anodizing solution is not particularly limited, but the upper limit is preferably 25 ° C. or less, and more preferably 20 ° C. or less, from the viewpoint of reaction uniformity. On the other hand, the lower limit of the temperature of the anodic oxidation solution is preferably 0 ° C. or higher, more preferably 10 ° C. or higher, from the viewpoint of reaction rate.

  In the porous formation step, when forming a plurality of through holes in the silicon substrate by anodizing treatment, through holes penetrating from one surface of the silicon substrate to the other surface may be formed in the anodizing treatment, Without completely penetrating, the silicon portion on the back surface of the silicon substrate (the surface opposite to the side where the anodizing solution is supplied) is left slightly, and the through-hole is removed by removing it later by plasma etching or the like. It may be formed. Further, by performing a surface treatment such as plasma etching after the anodizing treatment, the microporous layer on the surface of the silicon substrate can also be removed.

(Proton conduction region formation process)
The proton conducting region forming step is a step of forming a proton conducting region in the porous region of the silicon substrate provided with a plurality of pores in the porous forming step. As a method of forming a proton conductive region in the porous region, the pores in the porous region are filled with the electrolyte body such as the above-described electrolyte polymer having proton conductivity, or the pore wall is terminated with a sulfonic acid group. It can be formed by modifying with the molecule it has.

-Filling the electrolyte body-
A method for filling an electrolyte body such as an electrolyte polymer in the pores of the porous region is not particularly limited. Specifically, for example, a method of impregnating pores with a solution or dispersion of an electrolyte polymer or a molten electrolyte polymer; a solution or dispersion of a polymer precursor of an electrolyte polymer or a molten polymer precursor with pores After the polymer is impregnated, the polymer precursor is impregnated, or after the polymerization, a functional group that can be converted into an electrolyte group is converted into an electrolyte group. The method etc. can be mentioned.

  Specific examples of the impregnation method include, for example, a method in which a solution of the electrolyte polymer is dropped on a target region of a porous region, or a porous film is immersed in the solution, or the solution or melt is made porous. Examples of the coating method include various coating methods (die coating method, comma coating method, gravure coating method, roll coating method, bar coating method, reverse coating method, etc.). These may be used alone or in combination of two or more. In addition, at the time of the impregnation, one or more kinds of a crosslinking agent, a polymerization initiator (such as a photopolymerization initiator, a thermal initiator, a redox-based initiation polymerization initiator), a curing agent, a surfactant, and the like are included as necessary. It may be added.

  As described above, when forming a proton conduction region by dropping an electrolyte polymer solution into a porous region, for example, Nafion (registered trademark), which is an electrolyte polymer solution, is dropped into a target region to form a porous region. Proton conduction region formation can be formed by soaking. Further, after the dropping, the Nafion solution remaining on the silicon substrate surface or the like can be washed with isopropyl alcohol or the like.

  On the other hand, when a polymer precursor is used as described above, the polymer precursor contains at least one or more electrolyte monomers described above. Furthermore, you may contain a crosslinking agent as needed. Thus, when the polymer precursor and the crosslinking agent are used in combination, a crosslinking point can be formed during the production of the electrolyte polymer, so that it becomes easier to form a crosslinked body of the electrolyte polymer and is filled in the pores of the electrolyte membrane. Further, the insolubility and infusibility of the electrolyte polymer are improved, and it becomes difficult to drop off from the pores.

  Specific examples of the crosslinking agent include, for example, a compound having two or more polymerizable functional groups in one molecule, and a polymerizable double bond and other functional groups capable of crosslinking reaction in one molecule. And the like. These crosslinking agents may be contained in one kind or two or more kinds.

  Specific examples of the crosslinking agent having two or more polymerizable functional groups in one molecule include N, N′-methylenebis (meth) acrylamide, N, N′-ethylenebis (meth) acrylamide, N , N′-propylene bis (meth) acrylamide, N, N′-butylene bis (meth) acrylamide, polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, trimethylolpropane diallyl ether, pentaerythritol triallyl ether, Examples thereof include crosslinkable monomers such as divinylbenzene, bisphenol di (meth) acrylate, isocyanuric acid di (meth) acrylate, tetraallyloxyethane, triallylamine, diallyloxyacetate.

  Specific examples of the crosslinking agent having a polymerizable double bond and other functional group capable of crosslinking reaction in one molecule include N-methylolacrylamide, N-methoxymethylacrylamide, and N-butoxymethylacrylamide. And the like. These can be crosslinked after radical polymerization of a polymerizable double bond and heated to cause a condensation reaction or the like, or can be heated simultaneously with radical polymerization to cause a similar crosslinking reaction.

  The above-mentioned cross-linking agent is not limited to a compound having a carbon-carbon double bond, and although a polymerization reaction rate is slightly low, a bifunctional or higher epoxy compound, a compound having a phenyl group having a hydroxymethyl group, or the like is also used. You can also Moreover, when using the said epoxy compound, a crosslinking point is formed by reacting with acids, such as a carboxyl group contained in a polymer.

  The polymer precursor may further contain a monomer copolymerizable with the electrolyte monomer and / or the crosslinking agent, if necessary. Specific examples of this type of monomer include (meth) acrylic acid esters, (meth) acrylamides, maleimides, styrenes, organic acid vinyls, allyl compounds, and methallyl compounds. . These may be contained alone or in combination of two or more.

  The method for polymerizing the electrolyte monomer contained in the polymer precursor is not particularly limited, and any method that is generally known can be used. As such a polymerization method, for example, a thermal initiator such as a peroxide or an azo compound, a thermal polymerization using a redox polymerization initiator, or a photopolymerization initiator that generates radicals by irradiation with light such as ultraviolet rays was used. Examples thereof include photopolymerization, polymerization by electron beam and radiation. These may be used alone or in combination of two or more.

  The electrolyte polymer and / or polymer precursor is preferably used as a solution dissolved in an appropriate solvent or a dispersion liquid dispersed in an appropriate dispersion medium. In this case, the viscosity of the preferable dispersion is about 1 to 10000 mPa · s at 25 ° C. The viscosity is a value measured with a B-type viscometer.

  Specific examples of the solvent and dispersion medium include, for example, aromatic organic solvents such as toluene, xylene, and benzene, aliphatic organic solvents such as hexane and heptane, chlorinated solvents such as chloroform and dichloroethane, diethyl Ethers such as ether, ketones such as methyl ethyl ketone and cyclohexanone, esters such as ethyl acetate and butyl acetate, cyclic ethers such as 1,4-dioxane and tetrahydrofuran, dimethylformamide, dimethylacetamide, N-methyl-2-pyrrolidone And amide solvents, water, alcohols and the like. These may be contained alone or in combination of two or more. Moreover, it is preferable to mainly use water from the viewpoints of handleability and economy.

  The upper limit of the concentration of the solution or dispersion is preferably 100% by mass or less, more preferably 90% by mass or less, and particularly preferably 80% by mass or less from the viewpoint of higher performance when the concentration is higher. On the other hand, the lower limit of the concentration of the solution or dispersion is 5 from the viewpoint that if the concentration is too low, the filling becomes insufficient, or if the number of times is not repeated, the filling becomes difficult and the productivity deteriorates. It is preferably at least 10 mass%, more preferably at least 10 mass%, particularly preferably at least 20 mass%.

-Modification of molecule having sulfonic acid group at its terminal-
As described above, the proton conductive region can be formed by modifying the pore wall of the porous region with a molecule having a sulfonic acid group at the terminal. If the hole wall remains on the silicon surface, the change over time occurs due to natural oxidation. For this reason, when chemically modifying the pore wall, a method in which a silane coupling agent is adsorbed on a slightly thermally oxidized surface and then substituted with a molecule having a sulfonic acid group can be considered. For the method of modifying the sulfonic acid group by bonding monophenyltrimethoxysilane to the partially thermally oxidized pore wall at a low temperature of about 300 ° C., see S. Moghaddam, E. Pengwang, RI Masel, MA Shannon, Nanostructured Silicon. -based Proton Exchange Membrane for Micro Fuel Cells, Digest of PowerMEMS 2009, 116 (2009).

<Manufacturing method of fuel cell>
(Porous metal region forming process)
The production method of the present invention includes a porous metal region forming step. In the porous metal region forming step, the silicon substrate on which the porous proton conductive region is formed is dipped in a plating solution, and a catalytic metal is deposited in the porous region, respectively, on both sides of the porous proton conductive region. It is a step of forming a first porous metal region and a second porous metal region. The plating method for depositing the catalytic metal is not particularly limited, and a known plating method such as electroless plating or electrolytic plating can be used. In the porous metal region forming step, if the porous region of the silicon substrate is plated with a plating solution containing a catalytic metal made of a noble metal such as platinum in the porous region, the porous region may be affected by the difference in ionization tendency. The silicon and the catalytic metal such as platinum are substituted, and the catalytic metal can be deposited in the pores. In the production method of the present invention, only a desired surface layer of the porous region can be modified to porous platinum by applying a mask to a silicon substrate having a porous region as necessary and immersing it in a plating solution.

  The plating solution used in the plating method can be prepared, for example, by dissolving one or more soluble salts containing a supported catalytic metal as a constituent element in an appropriate solvent such as water. When electroless plating is performed, fluorine ions may be contained in the plating solution using hydrofluoric acid or the like. Usually, a catalytic metal such as platinum, which has a lower ionization tendency than silicon, receives electrons from silicon and is reduced and spontaneously precipitates, so that plating proceeds. However, with the progress of plating, an insulating film (silicon oxide film) that becomes a barrier to the progress of plating may be formed on the pore surface. In this case, if fluorine ions are contained in the plating solution using hydrofluoric acid or the like as described above, the formation of the insulating film is suppressed by the presence of the fluorine ions, and the plating is facilitated.

  The upper limit of the temperature of the plating solution is preferably 25 ° C. or less, and more preferably 20 ° C. or less from the viewpoint of nucleus growth and the like. On the other hand, the lower limit of the temperature of the plating solution is preferably 0 ° C. or higher, and more preferably 5 ° C. or higher, from the viewpoint of reaction rate.

(Slot formation process)
The manufacturing method of the present invention may include a groove forming step of forming a groove on the silicon substrate. The method for forming the grooves is not particularly limited, and for example, means such as wet etching with a tetramethylammonium hydroxide aqueous solution (TMAH) can be used. In this case, for example, the region to be the porous region on the silicon substrate and the region to be the silicon region are patterned, and the thickness of the region to be the porous region by wet etching with TMAH is in a desired range (for example, 50 μm Etching is performed until the level of the groove becomes a fuel channel on the surface of the silicon substrate.

  The groove forming process is not particularly limited in any stage, but in the present invention, the groove is formed by the groove forming process before the porous forming process, and then the porous region is formed. It is preferable to form.

(Insulating layer forming process)
In the production method of the present invention, it is possible to form an insulating layer for preventing the porous metal regions and the current collecting layers from being electrically joined via the silicon region. The method for forming the insulating layer is not particularly limited. For example, from the viewpoint of forming the porous metal region isolated from the silicon region, the silicon substrate on which the porous proton conductive region is formed by the proton conductive region forming step. An insulating layer is formed on one surface of the insulating layer so as to partially overlap the porous region by an insulating layer forming step, and then the porous region is modified with a catalyst metal such as platinum by the porous metal region forming step. The embodiment to be textured is preferred. As described above, when the insulating layer is formed so as to partially overlap the porous region by the insulating layer forming step before the porous metal region forming step, the insulating layer is formed during the plating process in the porous metal region forming step. Functions as a mask, and in a portion where the porous region and the insulating layer overlap with each other, the porous structure is not modified to the catalytic metal, and the porous region is maintained unmodified. Thereby, as shown in FIG. 1, a porous metal area | region (1st porous metal area | region 8A) can be isolated and formed so that it may not contact a silicon area | region.

  In addition, as described above, a paraxylylene polymer can be used as the material of the insulating layer. In the case where an insulating layer is formed on the surface of a silicon substrate using a paraxylylene polymer, the insulating film is formed by placing a glass mask or the like on a portion that becomes a porous metal region on the silicon substrate, and then depositing the paraxylylene polymer by CVD or the like. Can be formed.

On the other hand, when a silicon nitride film is used as the insulating layer, the insulating film can be formed on the silicon substrate before forming the porous region. In this case, a silicon nitride film is formed on the silicon substrate by CVD or the like, and the silicon nitride film is patterned by normal photolithography and dry etching using a gas such as CF ₄ . In this case, when the porous region is formed by anodic oxidation using the silicon nitride film as a mask, the region below the silicon nitride film opening is also made porous under the silicon nitride film. Thereafter, when a porous metal region is formed, a porous region that is not metallized remains between the silicon region 3 and the porous metal region 8A, so that insulation between the two can be maintained.

(Current collection layer formation process)
In the manufacturing method of the present invention, the first current collecting layer joined to the first porous metal region on one surface of the silicon substrate, and the second porous metal region on the other surface of the silicon substrate. A current collecting layer forming step of forming a second current collecting layer to be bonded can be included. The current collecting layer exposes only the portion where the current collecting layer is formed with a mask or the like, and forms the desired current collecting layer by sputtering gold or copper used as the material of the current collecting layer as described above. can do.

(Flow of manufacturing method of the present invention)
Hereinafter, an example of the flow of the manufacturing method of the present invention will be described with reference to FIG. FIG. 4 is an explanatory view showing an embodiment of the manufacturing process of the fuel cell of the present invention.

As shown in FIG. 4A, a silicon wafer (silicon substrate 2) with an SiO ₂ film 24 is prepared. Next, a positive photoresist film 26 is formed on the surface of the SiO ₂ film 24 by coating. After forming the coating film, the photoresist film 26 is subjected to pattern exposure through a mask, and the exposed portion is removed with a developer. As a result, as shown in FIG. 4B, a resist pattern is formed in which the SiO ₂ film 24 is exposed on the silicon substrate where the grooves serving as fuel flow paths are formed. A known method can be appropriately used for pattern formation by photolithography using the resist film and the developer.

Next, the SiO ₂ film 24 exposed from the pattern of the resist film 26 is removed from the silicon substrate 2 with a hydrofluoric acid buffer solution in which hydrofluoric acid is diluted (FIG. 4C). Since the resist film 26 on the remaining SiO ₂ film causes the solution to be contaminated during the etching of silicon, after the SiO ₂ film 24 is removed, the remaining resist film 26 is removed with a solvent such as acetone.

Next, the silicon substrate 2 on which the pattern of the SiO ₂ film 24 from which the resist film 26 has been removed is formed by wet etching using TMAH as described above. In the wet etching, the SiO ₂ film 24 is removed and the region where the silicon is exposed is gradually removed, and a recess is formed on the surface of the silicon substrate 2 as shown in FIG. At this time, the etching process is performed until the concave portion has a desired depth, and the concave portion later functions as the groove 15 (a groove forming step).

After the recess is formed on the surface of the silicon substrate 2, the remaining SiO ₂ film 24 on the silicon substrate 2 is removed with a hydrofluoric acid buffer solution or the like (FIG. 4E). After removing the SiO ₂ film 24, the silicon substrate 2 shown in FIG. 4E is anodized using a solution containing water, hydrofluoric acid, ethanol, etc. from the direction of the recess (etching surface). Form a porous region. At this time, a region to be a silicon region is masked by an O-ring. By the anodization treatment, a plurality of through holes are formed in a substantially vertical direction from the upper side of the paper surface of the silicon substrate 2 to the lower side of the paper surface, and the porous region 4 is formed (FIG. 4F). As the anodic oxidation process proceeds, through holes are formed from the upper side to the lower side of the paper surface of the silicon substrate 2 as described above. As shown in FIG. In the lower part, a silicon layer remains slightly like a thin skin.

  Next, plasma etching is performed on the silicon substrate 2 in which a plurality of through holes are formed, and the silicon layer remaining on the bottom surface of the silicon substrate and the microporous layer on the surface of the silicon substrate 2 are removed. (FIG. 4G). Thereby, the porous region 4 having a plurality of through holes penetrating from one surface of the silicon substrate 2 toward the other surface is formed (porous forming step).

  A Nafion (registered trademark) solution is added to the silicon substrate 2 on which the porous region 4 is formed from the surface where the concave portion is formed, and the Nafion solution is soaked into the through-hole portion of the porous region. Thereafter, the Nafion adhered to the surface or the like is washed with isopropyl alcohol, and a porous proton conductive region 6 is formed in the porous region 4 as shown in FIG. 4 (H) (proton conductive region forming step).

  Next, a glass mask is put on a part of the porous region 4 forming the porous metal region, and a paraxylylene polymer is formed on the other part to form the insulating layer 10 (insulating layer forming step). At this time, as shown in FIG. 4I, the insulating layer 10 formed of the paraxylylene-based polymer is formed so as to partially overlap (cover) the porous region.

  After the insulating layer 10 is formed, the silicon substrate 2 is immersed in a platinum plating solution stirred with a stirrer. Then, in the surface layer of the porous region 4 (including the porous proton conducting region 6) exposed on the surface of the silicon substrate 2, silicon and platinum in the porous region 4 are replaced and modified due to the difference in ionization tendency. Then, platinum is deposited in the pores of the porous region 4, and porous metal regions 8A and 8B are formed as shown in FIG. 4 (J) (porous metal region forming step). In FIG. 4, since the insulating layer 10 is partially covered and formed in the porous region 4 in the insulating film forming step, this serves as a mask and the first porous layer as shown in FIG. 4 (J). A solid metal region 8 A is formed separately from the silicon region 3.

  Subsequently, sputtering is performed on the silicon substrate 2 on which the porous metal region is formed, and current collecting layers 12 and 14 formed of Cr / Au or the like are formed, and as shown in FIG. The fuel cell 100 of the invention is completed.

  As mentioned above, although the fuel cell of this invention and its manufacturing method were demonstrated using embodiment, this invention is not limited only to the above-mentioned embodiment.

  Hereinafter, the present invention will be specifically described in Examples.

1. Cell fabrication As a sample, a silicon wafer with n-type, resistivity 0.008 to 0.02 Ωcm, thickness 110 ± 10 μm, double-sided mirror finish with oxide film is prepared, and photolithography is applied to the groove portion that becomes the fuel flow path A resist film (OFPF-800 manufactured by Tokyo Ohka Co., Ltd.) was patterned. Next, the silicon wafer was wet etched by wet etching using TMAH until the remaining thickness was about 50 μm, thereby forming a recess on the surface of the silicon wafer. Further, anodization was performed from the etched surface to form a porous region on the silicon wafer. The anodizing treatment was performed under the conditions shown in Table 1 below. Next, the silicon portion slightly remaining on the back surface of the silicon wafer and the microporous layer were removed by plasma etching.

  Next, a Nafion solution having the composition described in Table 1 below was dropped from the anodized surface of the silicon wafer and soaked into the porous region. At this time, the Nafion solution remaining on the surface was washed with isopropyl alcohol. Next, a glass mask is placed on the portion to be modified into the porous platinum layer, and dic-C (dichloroparacyclophane) (manufactured by Daisan Kasei Co., Ltd.) is formed on the other surface to form an insulating layer. did. Next, the silicon wafer on which the insulating layer was formed was immersed in a platinum plating solution stirred with a stirrer and subjected to a wet plating process. Thereby, the surface layer of both surfaces of the porous region was modified to porous platinum, and a porous metal region was formed. In addition, the wet plating process was performed according to the conditions described in Table 1.

  Finally, Cr / Au contact layers (current collection layers) were formed on both sides of the silicon wafer by sputtering to complete the cell.

2. Power generation experiment A power generation experiment was performed in a thermostatic chamber for the cell obtained above. The environmental temperature during the power generation experiment was 313 K, and the fuel was humidified hydrogen and non-humidified oxygen. The flow rate of hydrogen was 3 sccm, and the flow rate of oxygen was 1 sccm. As a result of the power generation experiment, a maximum power density of 17 mW / cm ² was recorded (FIG. 5). This proved that the structure functions as a fuel cell. FIG. 5 is a graph showing the voltage, current density, and output density characteristics of the cell according to the example. In FIG. 5, line A shows the relationship between cell voltage and current density, and line B shows the relationship between output density and current density. According to FIG. 5, it was confirmed that the fuel cell according to the example was operable as a battery and was excellent in durability and reliability.

2 Silicon substrate 3 Silicon region 4 Porous region 6 Porous proton conducting region 8A Porous metal region 8B Porous metal region 10 Insulating layer 12 Current collecting layer 14 Current collecting layer 15 Strip groove 16 Through hole 18 Stack structure 20 Conducting wire 22 Conducting wire 24 SiO ₂ film 26 Resist film 100 Fuel cell

Claims (3)

A porous region, wherein a silicon region provided around the porous region, a, and, on the porous region, a first porous metal area catalytic metal is supported, a porous proton conduction region And a silicon substrate comprising, in this order, a second porous metal region on which a catalytic metal is supported,
A first current collecting layer joined to the first porous metal region on one surface of the silicon substrate, and a second current joined to the second porous metal region on the other surface of the silicon substrate. A current collecting layer, an insulating layer provided on one surface of the silicon substrate,
Equipped with a,
At least one of the first porous metal region and the first current collecting layer, the second porous metal region and the second current collecting layer, and the silicon substrate. Electrically isolated from the silicon region,
The portion composed of the first porous metal region and the first current collecting layer and the portion composed of the second porous metal region and the second current collecting layer are insulated via the insulating layer. a fuel cell that. A porous region, and the silicon region provided around the porous region, and the insulating layer forming step of forming an insulating layer on one surface of the silicon substrate to have a,
A silicon substrate having a porous proton conductive region in the porous region is immersed in a plating solution, and a catalytic metal is deposited in the porous region, and a first porous metal is formed on each side of the porous proton conductive region. A porous metal region forming step of forming the region and the second porous metal region ;
A current collecting layer forming step of forming a first current collecting layer joined to the first porous metal region and a second current collecting layer joined to the second porous metal region, Current collection layer formation for forming the first current collection layer and the second current collection layer so that the first current collection layer and the second current collection layer are insulated via the insulating layer Process,
The method for producing a fuel cell according to claim 1, comprising: The insulating layer forming step, the one surface of the silicon substrate, a step of forming the insulating layer so as to partially overlap with the porous region, the porous metal region forming step, the insulating layer forming process for the preparation of a fuel cell according to claim 2, wherein the step of forming the first and second porous metal region in the silicon substrate.