JP2014123481A - Fuel battery cell, fuel cell stack, and methods of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel battery cell with high quality and excellent power generation performance, in which mechanical strength of a substrate being a metal support is reinforced and an efficient gas supply passage is secured, a fuel cell stack formed by laminating the cells, and methods of manufacturing the same.SOLUTION: A substrate 6 of a fuel battery cell 1 includes substrate-removed parts 12 which comprise substrate-removed recesses 9 from which the substrate 6 is removed by etching and micropore portions 10 having micropores 16 for transmitting a gas to a fuel electrode 3 and which communicate with a gas supply part 15 through which a fuel gas to be supplied to the fuel electrode 3 flows. In manufacturing the fuel battery cell 1, the substrate-removed recesses 9 are removed by etching before the fuel electrode 3, an electrolyte 5, and an oxidant electrode 4 are laminated on the substrate 6, and then the micropore portions 10 are removed by etching to provide the micropores 16 for transmitting the fuel gas to the fuel electrode 3.

Description

  The present invention relates to a fuel cell, a fuel cell stack, and a method for producing the same, and more particularly, in a solid oxide fuel cell, a metal support for holding an electrolyte made of a solid oxide, a fuel electrode, and an oxidant electrode. The present invention relates to a fuel cell having a substrate as a material, a fuel cell stack, and a method for manufacturing the same.

A solid oxide fuel cell (SOFC) is also called a solid electrolyte fuel cell, and is a fuel cell in which a solid electrolyte that conducts oxide ions, such as yttria-stabilized zirconia, is used as a solid electrolyte. Using this solid electrolyte as a partition wall, a fuel electrode (anode) is provided on one side surface, and a fuel gas such as hydrogen is supplied to the fuel electrode, and an oxidant electrode is provided on the other side surface so that an oxidant gas such as air is supplied. Supplied to the oxidizer electrode (cathode). In this solid oxide fuel cell (SOFC), the oxide ions (O ²⁻ ) generated at the oxidant electrode are permeated through the solid electrolyte and reacted with a fuel gas such as hydrogen at the fuel electrode. It is a fuel cell that generates energy.

  As described above, when the fuel electrode (anode) and the oxidant electrode (cathode) are installed with the electrolyte interposed therebetween, the power generation element is configured to be a “single cell”. In the present specification, this “single cell” is referred to as a “fuel cell”. The power generation element (single cell) is stacked to obtain a high output, which is a “stack”. In the present specification, this is referred to as a “fuel cell stack”. In this “stack”, plate-like components that serve to block fuel gas and air are provided between the cells. This is generally referred to as a “separator” or “interconnector”, but is referred to herein as a “separator”. In addition to the function of sealing each cell, this separator generally has a function of creating a flow path through which gas flows and feeding fuel gas and oxidant gas.

  Solid oxide fuel cells (SOFCs) include flat SOFCs and cylindrical SOFCs as typical cell structures. A flat SOFC is composed of a flat fuel electrode (anode), electrolyte, and oxidant electrode (cathode) to form a flat power generation element (single cell). It is a structure that obtains high output. On the other hand, in the cylindrical SOFC, the outside of the cylindrical electrolyte is wound with one of the fuel electrode (anode) and the oxidant electrode (cathode), and the inside of the electrolyte is wound with the other of the fuel electrode (anode) and the oxidant electrode (cathode). It is a wound structure. In the fuel cell, the fuel cell stack, and the manufacturing method thereof according to the present invention, a case where it is applied to a planar SOFC will be described, but the features of the present invention may be applied to a cylindrical SOFC.

  FIG. 9 shows a configuration of a conventional fuel cell stack 40. The fuel cell 30 is alternately stacked with the separator 31. In FIG. 9, one fuel cell 30 and two first separators 31a and second separators sandwiching the fuel cell 30 are provided. Only 31b is shown. In the fuel cell 30, the planar fuel electrode 3 and the oxidant electrode 4 are stacked, and the fuel electrode 3 and the oxidant electrode 4 sandwich the electrolyte 5 to constitute the power generation element 2.

  The first separator 31a and the second separator 31b are provided with a fuel gas channel 32 and an oxidant gas channel 33, respectively. A fuel gas 24 such as hydrogen is supplied from the fuel gas flow path 32 to the fuel electrode 3. An oxidant gas 25 such as air is supplied from the oxidant gas flow path 33 to the oxidant electrode 4. As shown in FIG. 9, the fuel gas channel 32 and the oxidant gas channel 33 are both unidirectional channels, and are provided independently on both surfaces of the first separator 31a and the second separator 31b, respectively. Accordingly, if one fuel cell 30 adjacent to the first separator 31a is the fuel electrode 3, the other fuel cell 30 adjacent to the first separator 31a becomes the oxidant electrode 4, and the fuel gas flow path 32 and the oxidant Each corresponds to the gas flow path 33. The fuel gas channel 32 and the oxidant gas channel 33 are, for example, a parallel channel method in which a channel is provided in the same direction, a counter channel method in which a channel is provided in the opposite direction, A cross flow path method in which flow paths are provided in a direction crossing each other is employed. In any of these flow path systems, the fuel gas 24 and the oxidizing gas 25 are separated and supplied by the separator 31 so as not to be mixed.

  As described above, when the fuel electrode and the oxidant electrode are installed with the solid electrolyte sandwiched therebetween, they become power generation elements. In general, since the electric resistance of the solid electrolyte becomes a power generation loss for the power generation element, in order to improve the power generation output density, it is necessary to reduce the film resistance by reducing the thickness of the solid electrolyte. On the other hand, since the solid electrolyte is an element constituting the power generation element, a certain amount of area is required. In other words, the cell components must have mechanical strength.

  In the case of a flat-plate SOFC, for example, an anode support cell using an anode as a support substrate and a cathode support cell using a cathode as a support substrate have been devised, but none of them can ensure sufficient strength as a cell support. There was a problem. Therefore, in addition to these power generation elements, a structure has been devised in which a metal support (metal-supported cell) that is a porous metal layer is added to the power generation element as a substrate. This metal-supported cell employs a metal substrate having excellent mechanical strength to support a power generation element, realize a thin solid electrolyte, and improve power generation efficiency.

  The flat solid oxide fuel cell (SOFC) using this metal support realizes thinning of the solid electrolyte and improves the power generation efficiency. On the other hand, the power generation element of the fuel electrode, the oxidant electrode, and the electrolyte Further, since the substrate is added, the configuration and function are complicated. Accordingly, various configurations and functions have been proposed regarding the positional relationship between the power generation element and the substrate, the fuel gas supply path to the fuel electrode, the oxidant gas supply path to the oxidant electrode, and the like.

  Patent Document 1 discloses a manufacturing method capable of providing a solid oxide fuel cell with excellent thermal shock resistance and high output density and capable of producing a solid oxide fuel cell with high productivity. Yes. Here, an electrolyte made of a solid oxide, a fuel electrode, and an air electrode are formed on a substrate that is a metal support. This substrate is composed of a dense gas-impermeable portion and a porous portion having gas permeability, and an electrolyte layer is formed by an aerosol deposition method so as to cover the porous portion. Then, after the electrolyte layer is formed, one of the fuel electrode and the air electrode is formed on the electrolyte layer. And the board | substrate of the part in which the electrolyte layer was formed is etched and made porous. Further, it is described that the other of the fuel electrode and the air electrode is formed below the porous portion, and the fuel electrode and the air electrode are formed on opposite surfaces across the substrate to constitute the power generation element.

  As described above, in Patent Document 1, a thin electrolyte layer is achieved by providing a metal support as a substrate. The air electrode (or fuel electrode) and the electrolyte layer are separated on one side of the substrate, and the fuel electrode (or air electrode) is separated and stacked on the other side of the substrate to form a power generation element. Also, a porous portion is formed on the substrate, and the fuel electrode (or air electrode) is in contact with the electrolyte layer to form a power generation element. Further, a fuel gas supply path to the fuel electrode and an oxidant gas supply path to the oxidant electrode are secured with the substrate interposed therebetween.

  In Patent Document 2, a power generation element including a dense solid electrolyte thin film and a gas flow path can be configured at a desired position on a substrate, and a solid oxide fuel cell excellent in output volume density can be obtained at low cost. It is disclosed to provide a cell body for a fuel cell and a method for producing such a cell body for a fuel cell. Here, in the cell body for a fuel cell, for example, an electrolyte layer and an electrode layer are formed at a desired portion of a metal support as a film formation substrate, and then a recess is formed in an arbitrary pattern at the film formation position of the metal support. In addition, it is described that a power generation element is configured by forming a porous portion at the bottom of a concave portion by etching to provide gas permeability.

  In the cell plate for a fuel cell shown in FIG. 1 of Patent Document 2, the gas support is used so that the fuel gas and the oxidant gas can be separately supplied by using the metal support as a fuel electrode and using the metal support as a partition. A configuration is shown in which fuel gas is supplied by a porous portion of a metal support that forms a channel. On the other hand, in the fuel cell plate shown in FIGS. 2, 4 and 5, the fuel electrode is covered with an electrolyte layer to form a gas flow path so that fuel gas and oxidant gas can be supplied separately. The structure in which the fuel gas is supplied to the fuel electrode by the porous portion of the metal support is shown.

  Thus, in patent document 2, the structural strength is ensured by providing the board | substrate which is a metal support body, and comprising a power generation element on it, and thinning of electrolyte is achieved. Further, a configuration is shown in which a gas flow path is formed so that fuel gas and oxidant gas can be supplied separately by using a substrate as a partition, and fuel gas is supplied through a hole portion of the substrate.

JP 2005-129370 A JP 2003-323901 A

  In the case of a cell for a fuel cell using a metal support shown in Patent Document 1, a gas supply path for supplying fuel gas and oxidant gas with a metal support interposed therebetween is provided, so that sufficient gas supply can be secured. . However, in order to provide sufficient power generation with the fuel electrode, electrolyte, and oxidant electrode by providing a porous portion on a part of the substrate that is the metal support, the porous structure has a width that allows sufficient gas supply. It is necessary to provide a part. However, the mechanical strength of this substrate is fragile due to the porous portion, and there is a problem that when the porous portion is enlarged to increase the gas supply efficiency, the mechanical strength decreases. As described above, since Patent Document 1 does not have a configuration that reinforces a substrate having weak mechanical strength due to the porous portion, a problem in strength of the substrate occurs.

  In addition, the porous portion is a portion where gas must be stably permeated, and the quality greatly affects the power generation performance. In Patent Document 1, the substrate is made porous by a single etching, but chemicals and the like are sprayed onto the substrate at a high pressure, resulting in rough processing, resulting in large variations in etching depth and porous hole diameter. The problem that is not stable occurs.

  In the case of the fuel cell using the metal support shown in Patent Document 2, the fuel cell plate shown in FIG. 1 has the same configuration as that of Patent Document 1 because the metal support is also used as the fuel electrode. Therefore, the porous part has a problem that the mechanical strength is weak. Also, in the fuel cell plate shown in FIGS. 2, 4 and 5, the porous portion must be provided with a sufficiently wide porous portion since the fuel gas must be supplied to the fuel electrode. However, this porous part has a problem that mechanical strength is weak. As described above, Patent Document 2 also has a problem in strength of the substrate because there is no configuration for reinforcing the substrate having weak mechanical strength by the porous portion. In the case of the fuel cell plate shown in FIGS. 2, 4 and 5, the metal support is bonded to the frame, but the reinforcing material for reinforcing the metal support is not shown.

  Moreover, this porous part is a part which must permeate | transmit gas stably similarly to patent document 1, and the quality has big influence on power generation performance. Therefore, even in Patent Document 2, the substrate is made porous by a single etching, but chemical processing or the like is sprayed on the substrate at a high pressure, resulting in rough processing, and variations in etching depth and porous hole diameter. The problem arises that the quality is not stable due to an increase in size.

  Furthermore, in a fuel cell stack in which fuel cell cells are stacked, when a substrate that is a metal support is provided in the configuration of a power generation element such as an electrolyte, a fuel electrode, and an oxidant electrode, the fuel gas and the oxidant gas are efficiently removed. There is a problem that a fuel gas supply path and an oxidant gas supply path to be supplied must be secured.

  The object of the present application is to solve this problem, reinforce the mechanical strength of the substrate as a metal support, ensure an efficient gas supply path, and have high quality and excellent power generation performance. The present invention also provides a fuel cell stack in which the cells are stacked, and a method for manufacturing the same.

  In order to achieve the above object, a fuel cell according to the present invention includes a first electrode that is one of a fuel electrode and an oxidant electrode, an electrolyte, a fuel electrode, and an oxidant on one surface of a substrate. A power generation element comprising a second electrode, which is the other of the poles, is sequentially stacked such that the first electrode is adjacent to the substrate, and the other surface of the substrate is positioned opposite the first electrode A substrate removing portion removed by etching and a reinforcing substrate protruding from the substrate to the opposite side of the first electrode and bonded thereto, and the substrate removing portion is removed so that the substrate forms a recess. It is characterized by comprising a substrate removal recess and a fine hole portion having a fine hole that passes through the substrate and allows gas to pass to the first electrode.

  With the above structure, the substrate is provided with a substrate removal portion that is removed by etching at a position facing the first electrode. As described above, by providing the substrate removal portion in the substrate, the fine holes removed by etching can be formed, and the fuel gas or the oxidant gas can be transmitted through the first electrode. And this board | substrate removal part is comprised from a board | substrate removal recessed part and a micropore part. That is, the substrate removal recess is removed by etching so that the substrate forms a recess without penetrating the substrate, but the microhole is formed by forming a microhole by etching penetrating the substrate, and the gas is supplied to the first electrode. Permeate up to. In this way, by dividing the substrate into two removed portions and etching, variations in the etching depth and the hole diameter of the fine holes can be reduced, and a fuel cell having high quality and excellent power generation performance can be obtained.

  A reinforcing substrate is bonded to the substrate. This reinforcing substrate can reinforce the mechanical strength of the substrate, making it possible to reduce the thickness of the substrate. By thinning the substrate, it is possible to reduce the amount to be removed by etching when etching the substrate in two parts to be removed, and to obtain a fuel cell having higher quality and superior power generation performance. It becomes possible. Moreover, when providing the micropore in the board | substrate 6, the role as a partition which hold | maintains the electric power generation element of the board | substrate thinned can be assisted. In other words, the substrate removal portion composed of the substrate removal recess and the fine hole portion is provided on the substrate. In this process, the power generation element composed of the fuel electrode, the electrolyte, and the oxidant electrode is laminated on the substrate. This fine hole portion is weak in mechanical strength, so that the phenomenon that the power generation element leaks or collapses from the substrate can be prevented, and the reinforcing substrate can assist the role of the partition wall of the substrate. Further, the reinforcing substrate protrudes from the substrate to the side opposite to the first electrode and is bonded. Thereby, an efficient gas supply path can be ensured by utilizing the reinforcing substrate adjacent to the substrate removing portion.

  The fuel cell preferably protrudes from the substrate so that the reinforcing substrate communicates with the substrate removal unit and forms a gas supply unit that supplies fuel gas or oxidant gas to the first electrode. Thereby, the mechanical strength of the substrate can be reinforced by the reinforcing substrate, and at the same time, an efficient gas supply path can be secured by utilizing the reinforcing substrate.

  The fuel cell preferably has a gas diffusion layer between the substrate and the first electrode. Thereby, the gas which permeate | transmitted the micropore provided in the board | substrate is diffused, and it spread | diffuses and reaches | attains to the wider range of a 1st electrode, It can be set as the cell for fuel cells excellent in electric power generation performance.

  Further, in the fuel cell, the substrate has a thickness in the range of about 0.005 mm to about 1.0 mm, and is made of nickel alloy, nickel-chrome stainless steel, or chrome stainless steel. It is possible to obtain a fuel cell having mechanical strength and a metal support excellent in the above.

  In addition, a fuel cell stack formed by stacking a plurality of fuel cell cells is provided with a gas supply unit surrounded by a substrate, a reinforcing substrate, and a separator that is installed adjacent to the substrate. Is preferably provided with a gas flow path that connects adjacent gas supply units. Thereby, an efficient fuel gas channel and oxidant gas channel can be easily secured in the fuel cell stack.

  In the fuel cell stack, a cell gas supply path including a gas supply section and a gas flow path for supplying fuel gas or oxidant gas to the first electrode is provided on the substrate, and fuel gas or oxidant gas is supplied to the separator. It is preferable that a separator gas supply path for supplying the second electrode is provided. As a result, it is possible to reduce the thickness of the separator by sharing either the fuel gas supply path or the oxidant gas supply path, both of which are conventionally provided in the separator, with the substrate and the reinforcing substrate. One of the fuel gas supply path and the oxidant gas supply path can be secured by utilizing the reinforcing substrate that is made to be simplified.

  In order to achieve the above object, a method of manufacturing a fuel cell according to the present invention includes a first electrode that is one of a fuel electrode and an oxidant electrode, an electrolyte, on one surface of a substrate, In the method of manufacturing a fuel cell, in which a power generation element comprising a second electrode that is the other of the fuel electrode and the oxidant electrode is sequentially stacked such that the first electrode is adjacent to the substrate, The step of removing the substrate so as to form a recess by etching at the position facing the first electrode on the other surface, and the first electrode, the electrolyte, and the second electrode on one surface of the substrate A step of laminating, and a step of providing, on the other surface of the substrate, a fine hole that penetrates the substrate by etching and allows gas to pass to the first electrode.

  With the above-described configuration, the substrate is removed so as to form a recess at a position facing the first electrode, and the micro-hole is formed through the substrate to allow gas to pass through to the first electrode. Etching is performed in two steps. In this way, the substrate is divided into two removed portions and etched stepwise, thereby reducing variations in etching depth and hole diameter of the fine holes, thereby providing a fuel cell having high quality and excellent power generation performance. Can do.

  The fuel cell manufacturing method preferably includes a step of adhering a reinforcing substrate that reinforces the substrate and forms a gas supply unit on the other surface of the substrate. Thereby, an efficient gas supply part can be provided by utilizing a reinforcing substrate that reinforces the mechanical strength of the substrate.

  In addition, in a method of manufacturing a fuel cell stack in which a plurality of fuel cell cells are stacked, a substrate is stacked via a separator, and a gas supply part is formed between the substrate and the reinforcing substrate on one surface of the separator. It is preferable that the separator is disposed adjacent to the substrate, and the other surface of the separator is disposed adjacent to the substrate so as to secure a gas supply path for supplying gas to the second electrode. Thereby, an efficient fuel gas channel and oxidant gas channel can be easily secured in the fuel cell stack.

  Further, in the method of manufacturing the fuel cell stack, fuel gas or oxidant gas is supplied to the first electrode through a cell gas supply path including a gas supply unit and a gas flow path, and the second electrode is provided on the separator. It is preferable that the fuel gas or the oxidant gas is supplied through the separator gas supply path. As a result, it is possible to reduce the thickness of the separator by sharing either the fuel gas supply path or the oxidant gas supply path, both of which are conventionally provided in the separator, with the substrate and the reinforcing substrate. One of the fuel gas supply path and the oxidant gas supply path can be secured by utilizing the reinforcing substrate that is made to be simplified.

  As described above, according to the fuel cell, the fuel cell stack, and the manufacturing method thereof according to the present invention, the mechanical strength of the substrate that is the metal support is reinforced, and an efficient gas supply path is ensured. In addition, it is possible to provide a fuel cell having high quality and excellent power generation performance, a fuel cell stack in which the cells are stacked, and a method for manufacturing them.

It is the top view and sectional view showing the schematic structure of one embodiment of the cell for fuel cells concerning the present invention. It is the top view and sectional drawing which show schematic structure of other embodiment of the cell for fuel cells which concerns on this invention. It is detailed sectional drawing which shows the structure of the gas generation part which consists of an electric power generation element, a board | substrate, a reinforcement board | substrate, and a board | substrate and a reinforcement board | substrate. It is an expanded sectional view which shows the detail of the board | substrate removal part and gas supply part of a cell for fuel cells. 1 is a perspective view showing a configuration of a fuel cell stack and a gas supply path according to the present invention. FIG. 3 is a bottom view of FIGS. 1 and 2 showing a gas supply path and a reinforcing substrate of a fuel cell. It is explanatory drawing which shows the step of the manufacturing method of the cell for fuel cells. It is a flowchart which shows the manufacturing method of the cell for fuel cells. It is a perspective view which shows the structure and gas supply path of the conventional fuel cell stack.

  Hereinafter, embodiments of a fuel cell 1, a fuel cell stack 20, and manufacturing methods thereof according to the present invention will be described in detail with reference to the drawings.

(Configuration of fuel cell)
FIG. 1 shows a schematic configuration of one embodiment of a fuel cell 1 according to the present invention. FIG. 2 shows a schematic configuration of another embodiment of the fuel cell 1 according to the present invention. That is, FIG. 1A shows a plan view of the fuel cell 1 in which the first power generation element 2 a is installed on the substrate 6. Further, FIG. 1B shows the AA cross section of FIG. 1A, FIG. 1C shows the BB cross section of FIG. 1A, and FIG. ) Of FIG. 1A is shown, and FIG. 1E shows the DD cross section of FIG. FIG. 2A is a plan view of the fuel cell 1 in which the second power generation element 2b is installed on the substrate 6. FIG. 2B shows a cross section taken along line EE in FIG. 2A, FIG. 2C shows a cross section taken along line FF in FIG. 2A, and FIG. 2D shows the cross section in FIG. A GG cross section is shown, and FIG. 2 (e) shows a HH cross section of FIG. 2 (a). FIG. 3 shows the details of the power generation element 2, the substrate 6, the reinforcing substrate 7, and the gas supply unit 15 in cross section. 4 (a) is an enlarged view of FIG. 3 showing details of the substrate removal unit 12 and the gas supply unit 15 of the fuel cell 1, and FIG. 4 (b) shows the J- J section is shown.

  As shown in FIGS. 1 and 2, the fuel cell 1 includes a substrate 6, a reinforcing substrate 7, and power generation elements 2a and 2b. The power generation elements 2a and 2b include a fuel electrode 3, an oxidant electrode 4, and It is composed of an electrolyte 5. That is, the fuel cell 1 according to the present invention is a metal-supported cell that uses a metal support as a base 6 for the power generation element 2.

  Although the board | substrate 6 is a substantially square board in this embodiment, it is not restricted to this, For example, other shapes, such as a rectangle and a circle, may be sufficient. The thickness of the substrate 6 is in the range of about 0.005 mm to about 1.0 mm. The substrate 6 is, for example, a metal made of nickel / chrome stainless steel or chrome stainless steel, but is not limited to these materials.

On one surface of the substrate 6, the first electrode 3 that is one of the fuel electrode and the oxidant electrode, the electrolyte 5, and the second electrode 4 that is the other of the fuel electrode and the oxidant electrode, The power generation elements 2a and 2b are stacked. That is, in the present embodiment, the power generating elements 2a and 2b are sequentially stacked such that the first electrode 3 faces the substrate 6 and the second electrode 4 and the first electrode 3 sandwich the electrolyte 5. 3 and the second electrode 4 may be reversed. In this embodiment, the fuel electrode is the first electrode 3 and the oxidant electrode is the second electrode 4, but the fuel electrode and the oxidant electrode may be reversed. In this specification, the reference numerals in the drawing indicate the fuel electrode as “3” and the oxidant electrode as “4”. As described above, the fuel electrode 3 and the oxidant electrode 4 are laminated with the electrolyte 5 interposed therebetween, so that the oxide ions (O ²⁻ ) generated in the oxidant electrode 4 permeate the electrolyte 5 and the fuel electrode. In step 3, the fuel cell reacts with the fuel gas to generate electric energy.

  FIG. 1 shows a fuel cell 1 when a rectangular first power generation element 2a is used, and FIG. 2 shows a fuel cell 1 when a circular second power generation element 2b is used. As described above, the power generation element 2 has a quadrangular shape or a circular shape, but is not limited thereto, and may be another shape such as a polygon such as a triangle or an ellipse. In the present embodiment, in the fuel cell 1, 25 power generation elements 2 are arranged in an orderly manner in 5 rows and 5 columns, but the number and arrangement of the power generation elements 2 per fuel cell 1 are not limited thereto. Absent.

  As shown in FIGS. 3 and 4, the substrate 6 is bonded to a reinforcing substrate 7 that reinforces the substrate 6. The reinforcing substrate 7 is bonded to the substrate at the surface indicated by the bonding surface 17. The reinforcing substrate 7 is a plate having the same dimensions as the substrate 6, but is not limited thereto, and may be another shape such as a rectangle or a circle. The reinforcing substrate 7 is made of the same material as that of the substrate 6, and is made of, for example, nickel / chrome stainless steel or chrome stainless steel, but is not limited to these materials. The bonding between the substrate 6 and the reinforcing substrate 7 is performed by diffusion bonding or brazing.

(Supply of fuel gas to the fuel electrode)
The fuel cell 1 is a fuel cell in which oxidant gas is supplied to the oxidant electrode 4 and fuel gas is supplied to the fuel electrode 3 to generate electrical energy. In the present embodiment, the oxidant electrode 4 that is the second electrode is stacked on the outermost end of the power generation element 2, so that the oxidant gas is supplied without any problem. On the other hand, since the fuel electrode 3 as the first electrode is in contact with the substrate 6, it is necessary to communicate the fuel gas supplied to the gas supply unit 15 to the fuel electrode 3.

  As shown in FIG. 4A, the substrate 6 has a substrate removal portion 12 that is removed by etching at a position facing the power generation element 2 on the surface opposite to the fuel electrode 3. The substrate removal portion 12, the substrate removal recess 9 that is removed so that the substrate 6 forms a recess, and the microhole portion 10 that has a microhole 16 that passes through the substrate 6 and allows gas to pass to the fuel electrode 3. The fuel gas 24 supplied to the fuel electrode 3 communicates with the gas supply unit 15 through which the fuel gas 24 flows. That is, the substrate removal portion 12 is formed by two-stage etching. The fine holes 16 are fine holes formed at a predetermined density in the region of the fine hole portion 10 by etching, and the fuel gas 24 flows through the fine holes 16.

  In the first etching, the substrate removal recess 9 is removed. The substrate removal recess 9 is removed in a bowl shape or a dome shape, but the depth of 50% to 90% of the thickness of the substrate 6 is removed to the extent that the substrate 6 does not penetrate. In the second etching, the surface removal portion 18 and the fine hole portion 10 between the substrate 6 and the reinforcing substrate 7 are removed. In this second etching, fine holes 16 penetrating the substrate 6 are provided. That is, the surface of the substrate 6 and the reinforcing substrate 7 is cut into a layer shape by the second etching, and the fine hole portion 10 that is an opening shown in FIG. 4B is provided. In this way, the substrate is divided into two removed portions and etched stepwise to reduce variations in etching depth and hole diameter of the fine holes 16, and the fuel cell 1 having high quality and excellent power generation performance. can do.

  As shown in FIG. 3, a gas diffusion layer 19 may be provided between the substrate 6 of the power generation elements 2 a and 2 b and the fuel electrode 3. By sandwiching the gas diffusion layer 19, the fuel gas 24 that has permeated through the fine holes 16 of the fine hole portion 10 provided in the substrate 6 is diffused to reach a wider range of the fuel electrode 3, thereby improving power generation efficiency. be able to.

(Three roles of reinforcing substrate)
The reinforcing substrate 7 in the present invention has the following three roles. First, the first role is to “reinforce the thickness of the substrate 6” by reinforcing the mechanical strength of the substrate 6. That is, the reinforcing substrate 7 is bonded to the substrate 6 with the protruding portion 11 that is “T-shaped”, whereby the rigidity in the out-of-plane direction of the substrate 6 is reinforced and the thickness can be reduced. FIG. 6 shows a reinforcing substrate 7 of the fuel cell 1 in a bottom view of FIGS. 1 and 2 as seen from the back side. The reinforcing substrate 7 is composed of a reinforcing substrate 7 at the center and reinforcing substrates 8 at both ends, and is integrally bonded to the substrate 6 so that the mechanical strength in the out-of-plane direction of the substrate 6 can be reinforced. Thereby, the thickness of the substrate 6 can be reduced, and when the fine holes 16 are provided in the substrate removal portion 12 of the substrate 6, the amount to be deleted by etching can be reduced, and the quality is higher and the power generation performance is excellent. The fuel cell 1 can be obtained.

  The second role of the reinforcing substrate 7 is to assist the “role as a partition wall for holding the power generation element 2” of the thinned substrate 6 when the fine holes 16 are provided in the substrate 6. A substrate removal portion 12 is provided that includes a substrate removal recess 9 and a minute hole portion 10 in which the minute hole 16 is provided in the substrate 6. In this process, the power generating element 2 composed of the fuel electrode 3, the electrolyte 5, and the oxidant electrode 4 is laminated on the substrate 6, but the micropore portion 10 provided with the micropores 16 is weak in mechanical strength. For this reason, there is a risk of leakage from the substrate 6 or collapse. That is, the substrate 6 has a “role as a partition for holding the power generation element 2” during processing. The reinforcing substrate 7 bonded to the substrate 6 assists the role of the substrate 6 as a partition wall.

  The third role of the reinforcing substrate 7 is to adhere to the substrate 6 with a “T-shaped” portion, and as shown in FIG. 3 and FIG. Forming a space for the supply section 15. Thereby, even if the thickness of the substrate 6 is reduced, a sufficient gas supply unit 15 can be secured. A gas flow path 13 is provided in a part of the reinforcing substrate 7 so as to communicate the adjacent gas supply portions 15 with each other. In the present embodiment, the gas flow path 13 is provided between the front end of the reinforcing substrate 7 and the separator 21. However, the present invention is not limited to this position, and a passage hole may be formed at an arbitrary position of the reinforcing substrate 7. As described above, in the fuel cell stack 20 in which the fuel cell 1 and the separator 21 are alternately stacked, a sufficient gas supply unit 15 is secured by the separator 21, and the gas supply unit 15 is communicated by the gas flow path 13. .

(Configuration of fuel cell stack)
FIG. 5 shows a configuration of the fuel cell stack 20 according to the present invention. The fuel cell 1 is alternately laminated with the separator 21, but in FIG. 5, one fuel cell 1 and two first separators 21 a and second separators sandwiching the fuel cell 1. Only 21b is shown. The fuel cell 1 includes a fuel electrode 3 that is a flat first electrode and an oxidant electrode 4 that is a second electrode, and the fuel electrode 3 and the oxidant electrode 4 sandwich an electrolyte 5 so as to generate a power generation element. 2 is configured.

  The first separator 21a and the second separator 21b are each provided with a separator gas supply path 14b, and the fuel cell 1 is provided with a cell gas supply path 14a. An oxidant gas 25 is supplied to the separator gas supply path 14b to the oxidant electrode 4 facing the inner separator 21 of the power generation element 2 stacked on the fuel cell 1. The separator gas supply path 14 b is a unidirectional flow path provided in the separator 21. Compared with the separator 21 of the conventional fuel cell stack 40 shown in FIG. 9, the flow path is unidirectional and the separator 21 itself can be thinned, and the processing is simplified.

  On the other hand, the fuel gas 24 is supplied to the cell gas supply path 14 a to the fuel electrode 3 facing the substrate 6 in the power generation element 2 stacked on the fuel cell 1. That is, the fuel gas 24 is supplied to the gas supply unit 15, and as shown in FIGS. 3 and 4, the fuel gas 24 is supplied to the substrate removal recess 9 that communicates with the gas supply unit 15 and the fine holes 16 of the fine hole part 10. And is supplied to the fuel electrode 3. Thus, in the conventional fuel cell 30 shown in FIG. 9, the fuel gas flow path 32 provided in the separator 31 is formed on the substrate 6 of the fuel cell 1 in the fuel cell 1 according to the present invention. The gas supply unit 15, the substrate removal recess 9, and the microhole 10 are provided.

  As shown in FIG. 3, in the fuel cell stack 20 according to the present invention, the gas supply unit 15 is provided by being surrounded by a substrate 6, a reinforcing substrate 7, and a separator 21 installed adjacent to the substrate 6. A part of the substrate 7 is provided with a gas flow path 13 that allows the adjacent gas supply units 15 to communicate with each other.

  FIG. 6 shows a cell gas supply path 14a of the fuel cell 1. A fuel gas 24 is supplied to the fuel electrode 3 through a cell gas supply path 14 a including a gas supply unit 15 and a gas flow path 13. That is, the fuel gas passage 22 is formed by the gas supply unit 15 and the gas passage 13 being continuous. On the other hand, an oxidant gas 25 is supplied to the oxidant electrode 4 via a separator gas supply path 14 b provided in the separator 21.

(Method for producing fuel cell)
In FIG. 7, the manufacturing method of the cell 1 for fuel cells is shown. FIG. 7A to FIG. 7D show an explanatory diagram of the method for manufacturing the fuel cell 1 for each step. FIG. 8 is a flowchart showing a method of manufacturing the fuel cell 1 from S1 to S4. Note that the four drawings from FIG. 7A to FIG. 7D correspond to the four steps in FIG.

  First, as shown in FIG. 7A, the substrate 6 is removed in a bowl shape or a dome shape by etching on the side of the substrate 6 opposite to the side where the power generating element 2 is provided (S1). The removed substrate removal recess 9 is provided at a position facing the installation position of the first electrode 3 of the power generation element 2. Then, the substrate 6 is removed to a depth of about 50% to 90% of the thickness of the substrate 6 so that no through hole is provided in the substrate 6. In this way, the substrate removal recess 9 is previously removed from the substrate 6 by edging. This edging is to remove the substrate 6 by spraying chemicals or the like at a high pressure on the substrate 6, but removing it to a depth of about 50% to 90% of the plate thickness in the state of the substrate 6 before processing. In this case, more accurate removal can be performed in the subsequent second removal of the substrate 6. Thereby, the variation in the depth of edging and the hole diameter of the fine hole 16 can be reduced.

  Next, as shown in FIG. 7B, the flat substrate 6 from which the substrate removing recess 9 has been removed is bonded to the reinforcing substrate 7 (S2). The board | substrate 6 and the reinforcement board | substrate 7 are adhere | attached on the adhesive surface shown with the code | symbol 17 of FIG.7 (b). This reinforcing substrate 7 is bonded to the side opposite to the side on which the power generating element 2 is provided on the substrate 6, and as shown in FIG. 6, the plate-like metal whose vertical and horizontal lengths are substantially the same as the substrate 6. It is. Then, as shown in FIG. 7B, a protruding portion 11 protruding in a “T shape” is provided on the opposite side of the substrate 6 from the side where the power generating element 2 is provided. By bonding the reinforcing substrate 7 having the protruding portion 11 to the substrate 6, the substrate 6 can increase the mechanical strength and can be thinned.

  Further, as shown in FIG. 7 (d), the reinforcing substrate 7 is bonded to the substrate 6 in a “T shape” to create a space for the gas supply unit 15. And the fuel gas flow path 22 is formed. In this way, by adhering the reinforcing substrate 7 forming the fuel gas flow path 22 to the substrate 6, a sufficient gas supply unit 15 can be secured even if the thickness of the substrate 6 is reduced.

  Next, as shown in FIG.7 (c), the electric power generation element 2 which consists of the 1st electrode 3, the electrolyte 5, and the 2nd electrode 4 is laminated | stacked on the board | substrate 6 (S3). Thus, by laminating the power generation element 2 at a stage where the entire thickness of the substrate 6 is not processed, it is possible to prevent the first electrode 3, the electrolyte 5, and the second electrode 4 from leaking from the substrate 6. Moreover, since the board | substrate 6 has already adhere | attached with the reinforcement board | substrate 7, even if the electric power generation element 2 is laminated | stacked, it has sufficient mechanical strength. Further, as shown in FIG. 3, a gas diffusion layer 19 may be provided between the substrate 6 of the power generation element 2 and the first electrode 3. Thereby, the gas which permeate | transmitted the micropore 16 of the micropore part 10 provided in the board | substrate 6 is diffused, reaches | attains the wider range of the 1st electrode 3, and can improve electric power generation efficiency.

  Next, as shown in FIG. 7D, the substrate 6 is removed again by etching on the side opposite to the side where the power generating element 2 is provided on the substrate 6. The removed surface removing portion 18 is provided at a position facing the fuel electrode 3 of the power generation element 2 and is indicated by a wavy line in FIG. Then, the fine hole portion 10 having the fine holes 16 that allow gas to pass to the first electrode 3 is provided by removal by this etching (S4). The fine holes 16 are fine holes formed at a predetermined density in the region of the fine hole portion 10 by etching, and the fuel gas 24 flows through the fine holes 16. As shown in FIG. 7A, this etching is removed to a depth of about 50% to 90% of the plate thickness in the state of the substrate 6 before processing, so that removal with higher accuracy is possible. Thereby, the variation in the depth of edging and the hole diameter of the fine hole 16 can be reduced.

  As described above, as a method of manufacturing the fuel cell 1, the step of removing the substrate 6 so as to form a recess at a position facing the fuel electrode 3 of the substrate 6 with respect to the substrate 6, Etching is performed in two steps including a step of providing fine holes 16 through which gas passes to the fuel electrode 3. Thus, by dividing the substrate 6 into two removed portions and etching in stages, the fuel cell 1 having high quality and excellent power generation performance can be obtained.

(Manufacturing method of fuel cell stack)
The separator 21 adjacent to the substrate 6 is provided so as to form the gas supply unit 15 between the substrate 6 and the reinforcing substrate 7. Thus, in the fuel cell stack 20 in which the fuel cell 1 and the separator 21 are alternately stacked, a sufficient gas supply unit 15 is secured by the separator 21. The reinforcing substrate 7 is bonded to the substrate 6 so as to provide a gas flow path 13 that allows the adjacent gas supply portions 15 to communicate with each other. The gas supply section 15 penetrates through the gas flow path 13, and a cell gas supply path 14 a is provided in the fuel cell 1.

  A fuel gas 24 or an oxidant gas 25 is supplied to the first electrode 3 via a cell gas supply path 14 a including a gas supply unit 15 and a gas flow path 13. In addition, the fuel gas 24 or the oxidant gas 25 is supplied to the second electrode 4 via a separator gas supply path 14 b provided in the separator 21. Thus, in the fuel cell stack 20, the gas supply paths 14 for the fuel gas 24 and the oxidant gas 25 are configured, and a high-quality fuel cell stack 20 is possible.

  DESCRIPTION OF SYMBOLS 1,30 Fuel cell, 2 Power generation element, 2a 1st power generation element, 2b 2nd power generation element, 3 1st electrode (fuel electrode), 4 2nd electrode (oxidant electrode), 5 electrolyte, 6 board | substrate, 7 Reinforcement substrate (center portion), 8 Reinforcement substrate (both ends), 9 Substrate removal recess, 10 Micro hole portion, 11 Projection portion, 12 Substrate removal portion, 13 Gas flow path, 14 Gas supply path, 14a Cell gas supply path, 14b Separator gas supply path, 15 gas supply section, 16 micropore, 17 bonding surface between substrate and reinforcing substrate, 18 surface removal section, 19 gas diffusion layer, 20, 40 fuel cell stack, 21, 31 separator, 21a, 31a first 1 separator, 21b, 31b 2nd separator, 22, 32 fuel gas flow path, 23, 33 oxidant gas flow path, 24 fuel gas, 25 oxidant gas.

Claims (10)

A power generation element comprising, on one surface of the substrate, a first electrode that is one of a fuel electrode and an oxidant electrode, an electrolyte, and a second electrode that is the other of the fuel electrode and the oxidant electrode Are sequentially stacked such that the first electrode is adjacent to the substrate,
The other surface of the substrate is provided with a substrate removing portion that is removed by etching at a position facing the first electrode, and a reinforcing substrate that protrudes and adheres to the opposite side of the first electrode from the substrate,
The substrate removing portion includes a substrate removing concave portion that is removed so that the substrate forms a concave portion, and a fine hole portion that has a fine hole that allows gas to pass through the substrate to the first electrode. A fuel cell.   2. The fuel cell according to claim 1, wherein the reinforcing substrate communicates with the substrate removing portion and protrudes from the substrate so as to form a gas supply portion that supplies fuel gas or oxidant gas to the first electrode. A fuel cell.   3. The fuel cell according to claim 1, wherein a gas diffusion layer is provided between the substrate and the first electrode. 4.   4. The fuel cell according to claim 1, wherein the substrate has a thickness in a range of approximately 0.005 mm to approximately 1.0 mm, and is formed of a nickel alloy, nickel chrome stainless steel. Or a cell for a fuel cell, comprising chrome stainless steel.   A fuel cell stack comprising a plurality of fuel cell cells according to any one of claims 1 to 4, wherein the gas supply unit is disposed adjacent to the substrate, the reinforcing substrate, and the substrate. A fuel cell stack, wherein the fuel cell stack is provided so as to be surrounded by a separator, and a gas flow path that connects adjacent gas supply portions to each other is provided in a part of the reinforcing substrate.   6. The fuel cell stack according to claim 5, wherein the substrate is provided with a cell gas supply path including a gas supply section and a gas flow path for supplying a fuel gas or an oxidant gas to the first electrode, and the separator is provided in the separator. A fuel cell stack comprising a separator gas supply path for supplying a fuel gas or an oxidant gas to the second electrode. A power generation element comprising, on one surface of the substrate, a first electrode that is one of a fuel electrode and an oxidant electrode, an electrolyte, and a second electrode that is the other of the fuel electrode and the oxidant electrode However, in the method of manufacturing a fuel cell, the first electrode is sequentially stacked so that the first electrode is adjacent to the substrate.
Removing the substrate so as to form a recess by etching at a position facing the first electrode on the other surface of the substrate;
Laminating a first electrode, an electrolyte and a second electrode on one side of the substrate;
Providing a fine hole on the other surface of the substrate through the substrate by etching and allowing gas to pass to the first electrode;
A method for producing a cell for a fuel cell, comprising:   8. The fuel cell manufacturing method according to claim 7, further comprising a step of bonding a reinforcing substrate that reinforces the substrate and forms a gas supply portion on the other surface of the substrate. A method for producing a battery cell.   9. A method of manufacturing a fuel cell stack comprising a plurality of fuel cell cells according to claim 8, wherein the substrate is laminated via a separator, and one surface of the separator is formed between the substrate and the reinforcing substrate. The separator is installed adjacent to the substrate so as to form a gas supply portion therebetween, and the other surface of the separator is installed adjacent to the substrate so as to secure a gas supply path for supplying gas to the second electrode. A method of manufacturing a fuel cell stack characterized by the above. 10. The method of manufacturing a fuel cell stack according to claim 9, wherein fuel gas or oxidant gas is supplied to the first electrode via a cell gas supply path including a gas supply part and a gas flow path, A fuel cell stack is supplied with fuel gas or oxidant gas via a separator gas supply path provided in the separator.

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