JP6800738B2 - How to make a fuel cell - Google Patents

Description

The present invention relates to a method for manufacturing a fuel cell, particularly a method for manufacturing a cell stack of a solid oxide fuel cell.

Fuel cells that generate electricity by chemically reacting fuel gas and oxygen are known. Of these, solid oxide fuel cells (SOFCs: Solid Oxcide Fuel Cell) are fuel cells that use oxides as solid electrolytes, and are being widely researched and developed because of their advantages of high efficiency. (See Patent Document 1).

As one aspect of the solid oxide fuel cell, there is a cylindrical horizontal stripe type SOFC cell stack. In this cylindrical horizontal stripe type SOFC cell stack, a fuel electrode, a solid electrolyte, and an air electrode are laminated on the outer peripheral surface of a tubular base tube to form a power generation element, and a plurality of these power generation elements are arranged in the axial direction of the base tube. It is arranged and configured by connecting a plurality of power generation elements in series by an interconnector.

In the SOFC cell stack having the above configuration, when fuel gas is supplied to the inside of the substrate tube and an oxidizing gas such as oxygen is supplied to the air electrode, the oxygen in the oxidizing gas supplied to the air electrode is ionized and the electrolyte. It penetrates the membrane and reaches the fuel electrode. Then, due to the electrochemical reaction between the oxygen ion reaching the fuel electrode and the fuel gas, a potential difference is generated between the fuel electrode and the air electrode, and power generation is performed by taking out this potential difference to the outside.

The SOFC cell stack is manufactured, for example, by screen-printing a slurry prepared from materials such as a fuel electrode, an electrolyte, and an interconnector on the surface of a substrate tube and firing it, and then forming and firing an air electrode slurry. ..

Japanese Unexamined Patent Publication No. 2004-134405

The slurry of each layer to be screen-printed has a similar color depending on the material used, and is difficult to distinguish. For _example, Y 2 _{O 3} stabilized ZrO ₂ (YSZ) solid electrolyte slurry prepared using white, interconnector slurry prepared using SrLaTiO ₃ such as SrTiO ₃ systems is white transparent.

Therefore, it is difficult to confirm the alignment of each layer during screen printing, and it is difficult to find even if there are defects such as unevenness or extremely thin film thickness due to insufficient slurry filling. There is a problem that it is difficult to judge the film formation status from the appearance.

In Patent Document 1, a plurality of slurries are colored with a food coloring agent, and the gradient composition of each of the deposited slurries is verified. However, the coloring made in Patent Document 1 remains in the layer after firing. For example, when the film formation position is confirmed by image recognition using a CCD camera when forming an air electrode, if the layer after firing remains colored as in Patent Document 1, the contrast is lowered. , There is a possibility that the accuracy of film formation position control using a CCD camera may be reduced.

The present invention has been made in view of such circumstances, and is easy to align when forming a functional material film such as a fuel electrode, a solid electrolyte, an interconnector, and an air electrode on a substrate tube. Moreover, it is an object of the present invention to provide a method for manufacturing a fuel cell in which defects are easily found.

In order to solve the above problems, the fuel cell manufacturing method of the present invention employs the following means.
The present invention is a method for manufacturing a fuel cell, which includes a fuel electrode, a solid electrolyte, and an air electrode, and includes a plurality of power generation elements arranged along the surface of the substrate, and an interconnector for connecting the adjacent power generation elements. The step of preparing the fuel electrode slurry, the solid electrolyte slurry, and the interconnector slurry, and the film forming positions of the fuel electrode slurry, the solid electrolyte slurry, and the interconnector slurry are managed on the substrate. A film forming step of forming a fuel electrode film, a solid electrolyte film and an interconnector film, and a firing step of heating the substrate tube, the fuel electrode film, the solid electrolyte film and the interconnector film together to obtain a sintered body. In the preparation of at least one of the fuel electrode slurry, the solid electrolyte slurry, and the interconnector slurry in the slurry preparation step, an oily solvent colorant is added to the slurry solvent to color the slurry. The present invention provides a method for producing a fuel cell, which decolorizes a color derived from the oil-based solvent colorant by heating in a firing step.

The slurry solvent is a solvent containing an aromatic hydrocarbon solvent, and the oily solvent colorant is preferably a compound composed of an aromatic compound.

By coloring the slurry solvent of the slurry to be printed on the substrate, it is possible to judge the appearance at the time of film formation, and it becomes easy to align the film formation and find defects. Defects include unevenness of the coating film and occurrence of locally thin parts of the coating film.

The oil-based solvent colorant is vaporized by heating in the firing step. Therefore, after the firing step, the colored color disappears and returns to the original color. If it does not return to the original color, it can be inferred that the firing process is incomplete, which is preferable. Since the oil-based solvent colorant is vaporized in the firing process, it does not affect the physical properties (performance) of the manufactured fuel cell if it is completely decolorized.

Usually, an air electrode is formed on the fuel electrode, the solid electrolyte, and the sintered body of the interconnector. At that time, the film forming position is read by checking the image of the CCD camera or the like at the position of the stripes of the interconnector. As in Patent Document 1, in the state where there is a colored film, the contrast is lowered at the time of image confirmation, so that the accuracy of image confirmation is lowered and the film forming position accuracy is lowered in the film forming process. there is a possibility. On the other hand, according to the above invention, the film containing the oil-based solvent colorant returns to the original color before the addition of the oil-based solvent colorant in the firing step, so that the film forming step of the air electrode is not adversely affected.

In one aspect of the above invention, the film containing the oily solvent colorant formed in the film forming step is subjected to a color tone inspection, and the soundness of the film is determined by the presence or absence of a change in the color tone from a predetermined color tone range at the initial stage of film forming. It is preferable to further include a confirmation step.

A compound composed of an aromatic compound as an oily solvent colorant has a property of discoloring when a defective substance (Na, S, Cl, etc.) in the atmosphere is mixed to form a compound. Therefore, the soundness of the film can be easily confirmed by the presence or absence of a change in the color tone from the predetermined range in the state at the initial stage of film formation of the film containing the oil-based solvent colorant.

In one aspect of the above invention, it is preferable to further include a step of recognizing the surface of the substrate on which the film containing the oil-based solvent colorant is formed and confirming the formation position of the film by the color tone.

The fuel electrode film, the solid electrolyte film, and the interconnector film are laminated so as to be displaced in the plane direction. According to one aspect of the above invention, the positional relationship between the colored film and other films laminated on the colored film can be easily confirmed. In particular, the interconnector film has a small overlap margin with the solid electrolyte membrane, but by coloring it, it can be confirmed whether or not the overlap is as specified.

According to the present invention, by coloring the slurry solvent, visibility in the film forming process can be improved, productivity and visual inspection can be improved, and the quality of the fuel cell can be improved.

It shows one aspect of the cell stack which concerns on one Embodiment of this invention. It shows one aspect of the cell stack which concerns on one Embodiment of this invention. It is a flow chart of cell stack manufacturing which concerns on one Embodiment of this invention. It is a figure which shows the structure of the solvent red 27 (C ₂₆ H ₂₄ N ₄ O). It shows one aspect of the SOFC module which concerns on one Embodiment of this invention. It shows one aspect of the cross section of the SOFC cartridge which concerns on one Embodiment of this invention.

Hereinafter, an embodiment of the method for manufacturing a fuel cell according to the present invention will be described with reference to the drawings.

In the following, for convenience of explanation, the positional relationship of each component is specified by using the expressions “top” and “bottom” with reference to the paper, but this does not necessarily have to be the case in the vertical direction. For example, the upward direction on the paper surface may correspond to the downward direction in the vertical direction. Further, the vertical direction on the paper surface may correspond to the horizontal direction perpendicular to the vertical direction.

Further, in the following, a cylindrical shape will be described as an example of the cell stack of the solid oxide fuel cell (SOFC), but this is not necessarily the case, and for example, a flat plate type cell stack may be used. Although the fuel cell is formed on the substrate, the electrode (fuel electrode or air electrode) may be formed thick without the substrate, and the substrate may also be used.

[First Embodiment]
(Structure of cylindrical cell stack)
First, a cylindrical cell stack using a substrate tube will be described as an example of the present embodiment with reference to FIGS. 1 and 2. Here, FIGS. 1 and 2 show one aspect of the cell stack according to the present embodiment. FIG. 1 shows a cross section of the substrate tube along the axial direction. FIG. 2 shows the sides of the cell stack. The substrate tube does not necessarily have to be cylindrical, and may be flat.

The cell stack 101 includes a cylindrical base tube 103, a plurality of fuel cell (power generation element) 105 formed on the outer peripheral surface of the base tube 103, and an interconnector 107 formed between adjacent fuel cell cells 105. To be equipped. The fuel cell 105 is formed by laminating a fuel electrode 109, a solid electrolyte 111, and an air electrode 113. Further, the cell stack 101 is attached to the air electrode 113 of the fuel cell 105 formed at one end of the plurality of fuel cell 105 formed on the outer peripheral surface of the base pipe 103 in the axial direction of the base pipe 103. , A lead portion 115 electrically connected via an interconnector 107, and a lead portion 115 electrically connected to a fuel pole 109 of a fuel cell 105 formed at the other end of the end.

(Description of materials and functions of each component of the cell stack)
Substrate tube 103 is made of a porous material, for example, CaO-stabilized _ZrO 2 (CSZ), a mixture of CSZ and nickel oxide (NiO) (CSZ + NiO) , or _Y 2 _{O 3} stabilized ZrO ₂ (YSZ), or The main component is MgAl ₂ O _{4 and the} like. The base tube 103 supports the fuel cell 105, the interconnector 107, and the lead portion 115, and the fuel gas supplied to the inner peripheral surface of the base tube 103 is supplied to the inner peripheral surface of the base tube 103 through the pores of the base tube 103. It is diffused in the fuel electrode 109 formed on the outer peripheral surface of the above.

The fuel electrode 109 is composed of an oxide of a composite material of Ni and a zirconia-based electrolyte material, and for example, Ni / YSZ is used. The thickness of the fuel electrode 109 is 50 μm to 250 μm. In this case, in the fuel electrode 109, Ni, which is a component of the fuel electrode 109, has a catalytic action on the fuel gas. This catalytic action reacts a fuel gas supplied via the substrate tube 103, for example, a mixed gas of methane (CH ₄ ) and water vapor, and reforms it into hydrogen (H ₂ ) and carbon monoxide (CO). It is a thing. Further, the fuel electrode 109 is an interface between hydrogen (H ₂ ) and carbon monoxide (CO) obtained by reforming and oxygen ions (O ^2- ) supplied via the solid electrolyte 111 with the solid electrolyte 111. It reacts electrochemically in the vicinity to produce water (H ₂ O) and carbon dioxide (CO ₂ ). At this time, the fuel cell 105 generates electricity by the electrons emitted from the oxygen ions.

The fuel gases that can be supplied and used for the fuel electrode 109 of SOFC10 include hydrocarbon gases such as hydrogen (H ₂ ), carbon monoxide (CO), and methane (CH ₄ ), city gas, and natural gas, as well as oil. Examples thereof include gas produced from carbonaceous raw materials such as methanol and coal gas by a gasification facility.

As the solid electrolyte 111, YSZ having airtightness that makes it difficult for gas to pass through and high oxygen ion conductivity at high temperature is mainly used. The solid electrolyte 111 moves oxygen ions ( ^O2- ) generated at the air electrode 113 to the fuel electrode 109. The film thickness of the solid electrolyte 111 located on the surface of the fuel electrode 109 is 10 μm to 100 μm.

The air electrode 113 is composed of, for example, a LaSrMnO _3- based oxide or a LaCoO _3- based oxide. The air electrode 113 dissociates oxygen in an oxidizing gas such as supplied air in the vicinity of the interface with the solid electrolyte 111 to generate oxygen ions ( ^O2- ).

The air electrode 113 may have a two-layer structure. In this case, the air electrode layer (air electrode intermediate layer) on the solid electrolyte 111 side is made of a material having high ionic conductivity and excellent catalytic activity. The air electrode layer (air electrode conductive layer) on the air electrode intermediate layer may be composed of a perovskite-type oxide represented by Sr and Ca-doped LaMnO ₃ . By doing so, the power generation performance can be further improved.

The interconnector 107 is composed of a conductive perovskite-type oxide represented by M _1-x L _x TiO ₃ (M is an alkaline earth metal element and L is a lanthanoid element) such as SrTiO ₃ system. The interconnector 107 has a dense film so that the fuel gas and the oxidizing gas do not mix with each other, and has stable durability and electrical conductivity in both an oxidizing atmosphere and a reducing atmosphere. In the adjacent fuel cell 105, the interconnector 107 electrically connects the air pole 113 of one fuel cell 105 and the fuel pole 109 of the other fuel cell 105, and the adjacent fuel cell 105s are connected to each other. Are connected in series.

Since the lead portion 115 needs to have electron conductivity and a coefficient of thermal expansion close to that of other materials constituting the cell stack 101, Ni such as Ni / YSZ and a zirconia-based electrolyte material are used. It is composed of M _1-x L _x TiO ₃ (M is an alkaline earth metal element and L is a lanthanoid element) such as a composite material or SrTiO ₃ system. The lead portion 115 leads out the DC power generated by the plurality of fuel cell 105s connected in series by the interconnector 107 to the vicinity of the end portion of the cell stack 101. The lead part is a layer 115a of a composite material of Ni such as Ni / YSZ and a zirconia-based electrolyte material, and M _1-x L _x TiO ₃ such as SrTiO ₃ system laminated on the layer 115a (M is alkaline soil). It may have a two-layer structure of layers 115b of a metal element and L is a lanthanoid element).

(Cell stack manufacturing process)
FIG. 3 shows a flow chart of cell stack manufacturing according to the present embodiment.

S1: Formation of the substrate tube The substrate tube 103'(not shown) (before firing) is formed by, for example, an extrusion molding method. The diameter of the formed substrate tube 103'is substantially uniform in the axial direction.

S2: Slurry preparation Fuel electrode slurry, solid electrolyte slurry, and interconnector slurry are prepared respectively.

The fuel electrode slurry is prepared by mixing the powder of the fuel electrode material and the slurry solvent. The solid electrolyte slurry is prepared by mixing the powder of the solid electrolyte material and the slurry solvent. The interconnector slurry is prepared by mixing the powder of the interconnector material and the slurry solvent.

Here, the slurry solvent is squeegee oil (a mixture of a screen printing solvent such as an aromatic hydrocarbon solvent and a binder such as methyl methacrylate). Diluents may be added to the slurry solvent to adjust the viscosity and yield value.

An oily solvent colorant is appropriately added to the slurry solvent to at least one film of the fuel electrode slurry, the solid electrolyte slurry, and the interconnector slurry. When coloring a plurality of slurries, they are color-coded with other films. The color coding may be a combination of colors that can be easily identified by the operator or image recognition.

An oil-based solvent colorant is an ink in which a pigment is dispersed in a volatile solvent. Select an oil-based solvent colorant that satisfies the following conditions.
(1) No component remains as a foreign substance after the firing step.
(Can be vaporized by heating in the subsequent firing process)
(2) In the firing step, the film is not damaged by foaming or the like.
(3) It is not necessary to consider the working environment for the use of the oil-based solvent colorant.

For example, the oil-based solvent colorant is a compound composed of an aromatic compound, and commercially available products include Solvent Red 27, Solvent Yellow 93 (C ₂₁ H ₁₈ N ₄ O ₂ ), and Solvent Blue, which are used as components of inkjet inks. 35 (C ₂₂ H ₂₆ N ₂ O ₂ ) and the like can be used. FIG. 4 shows the structure of Solvent Red 27 (C ₂₆ H ₂₄ N ₄ O, melting point 120 ° C., commercially available trade name). Solvent red has the property of being decomposed and volatilized at 130 ° C.

In the slurry preparation, for example, about 50 to 70% by weight of the powder, about 20 to 40% by weight of the squeegee oil, and 5 to 10% by weight of the diluent are mixed. The viscosity is 1.0 to 2.0 Pa · S, and the yield value is 30 to 100 Pa. The oil-based solvent colorant is added in an amount of 0.1 to 2% by weight, for example, to the extent that the slurry is colored and the viscosity does not change significantly.

S3: Film formation The fuel electrode slurry, the solid electrolyte slurry, and the interconnector slurry are sequentially printed on the substrate tube 103'to form the fuel electrode film, the solid electrolyte film, and the interconnector film.

First, the fuel electrode slurry is screen-printed in a plurality of sections corresponding to the number of fuel cell cells in the circumferential direction on the outer peripheral surface of the base tube 103'to form a fuel electrode film. In the present embodiment, the lead portion 115 may be made of the same material as the fuel electrode 109, and may be further laminated with layers made of the same material as the interconnector 107. The fuel electrode slurry is screen-printed on both ends of the cell group as a lead portion slurry to form a lead portion film. Printing of the interconnector slurry will be described later.

Next, the solid electrolyte slurry is screen-printed in a plurality of sections corresponding to the number of fuel cell cells in the circumferential direction on the outer peripheral surface of the substrate tube 103'to form a solid electrolyte film. Most of the solid electrolyte membrane is laminated on the fuel electrode membrane. A part of the solid electrolyte membrane is in contact with the substrate tube 103'on one end side of the fuel electrode.

Next, the interconnector slurry is screen-printed in the circumferential direction on the outer peripheral surface on the substrate tube 103'at a position corresponding to the space between adjacent fuel cell cells. Further, the interconnector slurry may be printed on the lead film.

S4: Firing A substrate tube 103'(hereinafter abbreviated as substrate tube 103L (not shown)) in which a fuel electrode film, a solid electrolyte film, and an interconnector film are formed is subjected to a firing furnace and heated. Obtain a sintered body.

The baking step includes a degreasing step, a sintering step, and a temperature lowering step.
First, in the degreasing step, the substrate tube 103L is heated in the range of 200 ° C. to 400 ° C. for about 20 hours to 40 hours. As a result, the slurry solvent contained in the substrate tube 103L is gradually evaporated. As a result, the slurry solvent evaporates without damaging the substrate tube 103L. In the degreasing step, heating may be performed in a state where the oxygen concentration is low. As a result, it is possible to prevent the resin component as a binder (binder) contained in the slurry solvent from burning in a part of the substrate tube 103L and locally raising the temperature.

In the degreasing step, the oily solvent colorant is vaporized together with the slurry solvent. As a result, the color of the colorant is removed from the film to which the oil-based solvent colorant is added, and the original color (the color before the addition of the oil-based solvent colorant) is restored.

Next, the substrate tube 103L is heated so as to gradually raise the temperature to the sintering temperature. The temperature of the substrate tube 103L may be raised in stages. For example, the temperature is raised to a sintering temperature (1300 ° C. to 1500 ° C.) over a predetermined time (for example, about 4 hours to 10 hours), and the temperature is maintained for a predetermined time (for example, about 2 hours to 6 hours). Obtain a sintered body.

After firing, the substrate tube 103L is gradually cooled to room temperature. Cooling is performed by exchanging heat between water and the air in the furnace, blowing air into the furnace, and the like.

S5: Preparation of air electrode slurry (not shown)
Prepare an air electrode slurry. The air electrode slurry is prepared by mixing the powder of the air electrode material and the slurry solvent. Here, the slurry solvent is squeegee oil. Diluents may be added to the slurry solvent to adjust the viscosity and yield value.

S6: Film formation (not shown)
An air electrode slurry is formed on the outer peripheral surface of the substrate tube 103L (sintered body) fired in S4 using a dispenser. The air electrode slurry is discharged onto the solid electrolyte 111 and the interconnector 107. The discharged air electrode slurry (air electrode film) comes into contact with the solid electrolyte 111 and the interconnector 107 in the same fuel cell.

S7: Firing (not shown)
The substrate tube 103L on which the air electrode film is formed is placed in a firing furnace and fired at 1100 ° C. to 1250 ° C. for about 2 hours to 6 hours. The firing temperature is lower than the firing in S4.

According to the method for producing the cell stack 101 of the present embodiment, printing is performed and firing is performed by coloring at least one slurry solvent of the fuel electrode slurry, the solid electrolyte slurry, and the interconnector slurry without modifying the existing film forming apparatus. The visibility of the front membrane is improved. In addition to confirming the film formation position, it is produced by making it easier to visually recognize the filling condition (thickness) of the film such as surface irregularities and places where the film thickness is extremely thin, and the presence of air bubbles (unevenness). The accuracy of sex and visual inspection is improved, and the quality of cell stack can be improved.

[Second Embodiment]
The method for manufacturing a fuel cell according to the present embodiment includes a step of inspecting the color tone of a film containing an oil-based solvent colorant. The other steps are the same as those in the first embodiment. The color tone inspection is performed before the firing step.

In the step of confirming the color tone, the color tone of the film containing the oil-based solvent colorant formed in the film forming step is inspected. The inspection is carried out visually or by an image recognition means such as a CCD camera. When a defective substance such as Na, S or Cl dissolves in the film from the atmosphere, the oil-based solvent colorant mixed with the slurry solvent discolors the slurry film by combining with the oil-based solvent colorant. A part of the RGB component presents a color development intensity different from the color tone in a predetermined range when it is sound. Further, when the ambient brightness changes, it may be compared whether or not there is a change in the B / R and G / R values based on the R component color development intensity. The soundness of the film can be confirmed by observing and comparing the presence or absence of a change in the color tone from the predetermined range at the initial stage of film formation with a CCD camera. It is advisable to set a soundness threshold value in advance for the rate of change in color tone and the like.

[Third Embodiment]
The method for manufacturing a fuel cell according to the present embodiment includes a step of confirming the formation position of the film by the color tone of the film containing an oil-based solvent colorant. The other steps are the same as those in the first embodiment or the second embodiment. Confirmation of the formation position is carried out before the firing step.

In the step of confirming the formation position, the surface of the substrate tube 103L on which the film containing the oil-based solvent colorant is formed is image-recognized. By performing image recognition with a CCD camera or the like, the film formation position can be managed quickly and with high accuracy. With respect to the film containing the oil-based solvent colorant and the film not containing the oil-based solvent colorant, or between the films containing the color-coded oil-based solvent colorant, the film-forming position can be confirmed by the difference in color tone at the overlapping portion of the films. If the setting value of the overlap margin is narrow, there is a high possibility that the overlap will occur if the position is slightly displaced. By checking the degree of overlap at the film forming stage, it is possible to identify the occurrence of defective products at an early stage.

In addition to controlling the film formation position, it is easy to automatically recognize the filling condition (thickness) of the film and the presence of air bubbles (unevenness) such as the surface unevenness of the film and the part where the film thickness is extremely thin by image analysis. By doing so, it is possible to improve the accuracy of automatic monitoring at the time of mass production, and it is possible to improve productivity and improve the quality of the cell stack.

The formation of the film containing the oil-based solvent colorant may be confirmed visually instead of using the CCD camera.

(Explanation of SOFC module structure and function of each element)
Hereinafter, SOFC modules and SOFC cartridges using the cell stack 101 of the first to third embodiments will be described. FIG. 5 shows one aspect of the SOFC module according to the present embodiment. Further, FIG. 6 shows a cross-sectional view of one aspect of the SOFC cartridge according to the present embodiment.

As shown in FIG. 5, the SOFC module 201 includes, for example, a plurality of SOFC cartridges 203 and a pressure vessel 205 for accommodating the plurality of SOFC cartridges 203. Although FIG. 5 illustrates a cylindrical SOFC cell stack, this does not necessarily have to be the case, and a flat plate cell stack may be used, for example.

Further, the SOFC module 201 includes a fuel gas supply pipe 207 and a plurality of fuel gas supply branch pipes 207a, and a fuel gas discharge pipe 209 and a plurality of fuel gas discharge branch pipes 209a. Further, the SOFC module 201 includes an oxidizing gas supply pipe (not shown) and an oxidizing gas supply branch pipe (not shown), and an oxidizing gas discharge pipe (not shown) and a plurality of oxidizing gas discharge branch pipes (not shown). ) And.

The fuel gas supply pipe 207 is provided outside the pressure vessel 205, is connected to a fuel gas supply unit that supplies fuel gas having a predetermined gas composition and a predetermined flow rate according to the amount of power generated by the SOFC module 201, and a plurality of fuel gas supply pipes 207. It is connected to the fuel gas supply branch pipe 207a. The fuel gas supply pipe 207 is for branching and guiding the fuel gas of a predetermined flow rate supplied from the fuel gas supply unit described above to a plurality of fuel gas supply branch pipes 207a. Further, the fuel gas supply branch pipe 207a is connected to the fuel gas supply pipe 207 and is also connected to a plurality of SOFC cartridges 203. The fuel gas supply branch pipe 207a guides the fuel gas supplied from the fuel gas supply pipe 207 to the plurality of SOFC cartridges 203 at a substantially equal flow rate, and substantially equalizes the power generation performance of the plurality of SOFC cartridges 203. ..

The fuel gas discharge branch pipe 209a is connected to a plurality of SOFC cartridges 203 and is also connected to the fuel gas discharge pipe 209. The fuel gas discharge branch pipe 209a guides the exhaust fuel gas discharged from the SOFC cartridge 203 to the fuel gas discharge pipe 209. Further, the fuel gas discharge pipe 209 is connected to a plurality of fuel gas discharge branch pipes 209a, and a part of the fuel gas discharge pipe 209 is arranged outside the pressure vessel 205. The fuel gas discharge pipe 209 guides the exhaust fuel gas led out from the fuel gas discharge branch pipe 209a at a substantially equal flow rate to the outside of the pressure vessel 205.

Since the pressure vessel 205 is operated at an internal pressure of 0.1 MPa to about 1 MPa and an internal temperature of atmospheric temperature to about 550 ° C., it has resistance to resistance and corrosion resistance to oxidizing agents such as oxygen contained in the oxidizing gas. The material you have is used. For example, a stainless steel material such as SUS304 is suitable.

Here, in the present embodiment, a mode in which a plurality of SOFC cartridges 203 are assembled and stored in the pressure vessel 205 will be described, but the present invention is not limited to this, and for example, the SOFC cartridge 203 is not assembled and the pressure is increased. It can also be stored in the container 205.

(Explanation of SOFC cartridge structure and function of each element)
As shown in FIG. 6, the SOFC cartridge 203 includes a plurality of cell stacks 101, a power generation chamber 215, a fuel gas supply chamber 217, a fuel gas discharge chamber 219, an oxidizing gas supply chamber 221 and an oxidizing gas discharge chamber. It is equipped with 223. Further, the SOFC cartridge 203 includes an upper tube plate 225a, a lower tube plate 225b, an upper heat insulating body 227a, and a lower heat insulating body 227b. In the present embodiment, in the SOFC cartridge 203, the fuel gas supply chamber 217, the fuel gas discharge chamber 219, the oxidizing gas supply chamber 221 and the oxidizing gas discharge chamber 223 are arranged as shown in FIG. The structure is such that the fuel gas and the oxidizing gas flow opposite to the inside and the outside of the cell stack 101, but this is not always necessary. For example, the fuel gas and the oxidizing gas flow in parallel to the inside and the outside of the cell stack. Alternatively, the oxidizing gas may flow in a direction orthogonal to the longitudinal direction of the cell stack.

The power generation chamber 215 is a region formed between the upper heat insulating body 227a and the lower heat insulating body 227b. The power generation chamber 215 is a region in which the fuel cell 105 of the cell stack 101 is arranged, and is a region in which the fuel gas and the oxidizing gas are electrochemically reacted to generate electricity. Further, the temperature near the central portion of the cell stack 101 in the longitudinal axis direction of the power generation chamber 215 is monitored by a temperature sensor or the like, and becomes a high temperature atmosphere of about 700 ° C. to 1000 ° C. during steady operation of the SOFC module 201.

The fuel gas supply chamber 217 is an area surrounded by the upper casing 229a and the upper pipe plate 225a of the SOFC cartridge 203, and the fuel gas supply branch pipe 207a is provided by the fuel gas supply hole 231a provided in the upper part of the upper casing 229a. Is communicated with. The plurality of cell stacks 101 are joined to the upper pipe plate 225a by the seal member 237a, and the fuel gas supply chamber 217 receives the fuel gas supplied from the fuel gas supply branch pipe 207a through the fuel gas supply hole 231a. It is guided inside the base tubes 103 of the plurality of cell stacks 101 at a substantially uniform flow rate, and the power generation performance of the plurality of cell stacks 101 is substantially made uniform.

The fuel gas discharge chamber 219 is an area surrounded by the lower casing 229b and the lower pipe plate 225b of the SOFC cartridge 203, and communicates with the fuel gas discharge branch pipe 209a by the fuel gas discharge hole 231b provided in the lower casing 229b. Has been done. The plurality of cell stacks 101 are joined by a lower pipe plate 225b and a sealing member 237b, and the fuel gas discharge chamber 219 passes through the inside of the base pipe 103 of the plurality of cell stacks 101 and is supplied to the fuel gas discharge chamber 219. The exhaust fuel gas to be generated can be aggregated and guided to the fuel gas discharge branch pipe 209a through the fuel gas discharge hole 231b.

Oxidizing gas having a predetermined gas composition and a predetermined flow rate is branched into an oxidizing gas supply branch pipe according to the amount of power generated by the SOFC module 201, and is supplied to a plurality of SOFC cartridges 203. The oxidizing gas supply chamber 221 is an area surrounded by the lower casing 229b, the lower pipe plate 225b, and the lower heat insulating body 227b of the SOFC cartridge 203, and is provided by the oxidizing gas supply hole 233a provided on the side surface of the lower casing 229b. , It is communicated with an oxidizing gas supply branch pipe (not shown). The oxidizing gas supply chamber 221 transfers an oxidizing gas having a predetermined flow rate supplied from an oxidizing gas supply branch pipe (not shown) through the oxidizing gas supply hole 233a to the power generation chamber 215 via the oxidizing gas supply gap 235a. It can be derived with a substantially uniform flow rate.

The oxidizing gas discharge chamber 223 is an area surrounded by the upper casing 229a, the upper pipe plate 225a, and the upper heat insulating body 227a of the SOFC cartridge 203, and is provided by the oxidizing gas discharge holes 233b provided on the side surface of the upper casing 229a. , It communicates with an oxidizing gas discharge branch pipe (not shown). In this oxidizing gas discharge chamber 223, the oxidative gas supplied from the power generation chamber 215 to the oxidative gas discharge chamber 223 via the oxidative gas discharge gap 235b is not shown through the oxidative gas discharge hole 233b. It can lead to an oxidizing gas discharge branch pipe.

In the upper casing 225a, the upper casing 229a is provided so that the upper tube plate 225a, the top plate of the upper casing 229a, and the upper heat insulating body 227a are substantially parallel to each other between the top plate of the upper casing 229a and the upper heat insulating body 227a. It is fixed to the side plate of. Further, the upper tube plate 225a has a plurality of holes corresponding to the number of cell stacks 101 provided in the SOFC cartridge 203, and the cell stacks 101 are inserted into the holes, respectively. The upper tube plate 225a airtightly supports one end of the plurality of cell stacks 101 via either one or both of the sealing member and the adhesive member, and the fuel gas supply chamber 217 and the oxidizing gas discharge chamber 223. It isolates and.

The lower tube plate 225b is attached to the side plate of the lower casing 229b so that the bottom plate of the lower tube plate 225b, the bottom plate of the lower casing 229b, and the lower heat insulating body 227b are substantially parallel to each other between the bottom plate of the lower casing 229b and the lower heat insulating body 227b. It is fixed. Further, the lower tube plate 225b has a plurality of holes corresponding to the number of cell stacks 101 provided in the SOFC cartridge 203, and the cell stacks 101 are inserted into the holes, respectively. The lower tube plate 225b airtightly supports the other end of the plurality of cell stacks 101 via either one or both of the sealing member and the adhesive member, and the fuel gas discharge chamber 219 and the oxidizing gas supply chamber 221. It isolates and.

The upper heat insulating body 227a is arranged at the lower end of the upper casing 229a so that the upper heat insulating body 227a, the top plate of the upper casing 229a, and the upper tube plate 225a are substantially parallel to each other, and is fixed to the side plate of the upper casing 229a. There is. Further, the upper heat insulating body 227a is provided with a plurality of holes corresponding to the number of cell stacks 101 provided in the SOFC cartridge 203. The diameter of this hole is set to be larger than the outer diameter of the cell stack 101. The upper heat insulating body 227a includes an oxidizing gas discharge gap 235b formed between the inner surface of the hole and the outer surface of the cell stack 101 inserted through the upper heat insulating body 227a.

The upper heat insulating body 227a separates the power generation chamber 215 and the oxidizing gas discharge chamber 223, and the atmosphere around the upper pipe plate 225a becomes high in temperature, resulting in a decrease in strength and corrosion by the oxidizing agent contained in the oxidizing gas. Suppress the increase. The upper tube plate 225a and the like are made of a metal material having high temperature durability such as Inconel, but the upper tube plate 225a and the like are exposed to the high temperature in the power generation chamber 215 and the temperature difference in the upper tube plate 225a and the like becomes large. It prevents thermal deformation. Further, the upper heat insulating body 227a guides the oxidative gas that has passed through the power generation chamber 215 and exposed to high temperature to the oxidative gas discharge chamber 223 by passing through the oxidative gas discharge gap 235b.

According to the present embodiment, due to the structure of the SOFC cartridge 203 described above, the fuel gas and the oxidizing gas flow toward the inside and the outside of the cell stack 101. As a result, the oxidative gas exchanges heat with the fuel gas supplied to the power generation chamber 215 through the inside of the base tube 103, and the upper tube plate 225a and the like made of a metal material buckle and the like. It is cooled to a temperature at which it does not deform and is supplied to the oxidizing gas discharge chamber 223. Further, the fuel gas is heated by heat exchange with the oxidative gas discharged from the power generation chamber 215 and supplied to the power generation chamber 215. As a result, the fuel gas preheated and raised to a temperature suitable for power generation can be supplied to the power generation chamber 215 without using a heater or the like.

The lower heat insulating body 227b is arranged at the upper end of the lower casing 229b so that the lower heat insulating body 227b, the bottom plate of the lower casing 229b, and the lower tube plate 225b are substantially parallel to each other, and is fixed to the side plate of the lower casing 229b. .. Further, the lower heat insulating body 227b is provided with a plurality of holes corresponding to the number of cell stacks 101 provided in the SOFC cartridge 203. The diameter of this hole is set to be larger than the outer diameter of the cell stack 101. The lower heat insulating body 227b includes an oxidizing gas supply gap 235a formed between the inner surface of the hole and the outer surface of the cell stack 101 inserted through the lower heat insulating body 227b.

The lower heat insulating body 227b separates the power generation chamber 215 and the oxidizing gas supply chamber 221, and the atmosphere around the lower pipe plate 225b becomes high in temperature, resulting in a decrease in strength and corrosion by the oxidizing agent contained in the oxidizing gas. Suppress the increase. The lower tube plate 225b or the like is made of a metal material having high temperature durability such as Inconel, but the lower tube plate 225b or the like is exposed to a high temperature and the temperature difference in the lower tube plate 225b or the like becomes large, so that it is thermally deformed. It is something to prevent. Further, the lower heat insulating body 227b guides the oxidizing gas supplied to the oxidizing gas supply chamber 221 to the power generation chamber 215 through the oxidizing gas supply gap 235a.

According to the present embodiment, due to the structure of the SOFC cartridge 203 described above, the fuel gas and the oxidizing gas flow toward the inside and the outside of the cell stack 101. As a result, the exhaust fuel gas that has passed through the inside of the base pipe 103 and passed through the power generation chamber 215 is heat-exchanged with the oxidizing gas supplied to the power generation chamber 215, and the lower pipe plate 225b made of a metal material is exchanged. Etc. are cooled to a temperature at which deformation such as buckling does not occur and supplied to the fuel gas discharge chamber 219. Further, the oxidizing gas is heated by heat exchange with the exhaust fuel gas and supplied to the power generation chamber 215. As a result, the oxidizing gas heated to the temperature required for power generation can be supplied to the power generation chamber 215 without using a heater or the like.

The DC power generated in the power generation chamber 215 is led out to the vicinity of the end of the cell stack 101 by the lead portion 115 made of Ni / YSZ or the like provided in the plurality of fuel cell 105, and then the current collecting rod of the SOFC cartridge 203 (non-collective rod). The current is collected by the current collector plate (not shown) on the (shown), and is taken out to the outside of each SOFC cartridge 203. The DC power derived to the outside of the SOFC cartridge 203 by the collector rod connects the generated power of each SOFC cartridge 203 to a predetermined number of series and parallel numbers, and is led out to the outside of the SOFC module 201. It is converted into predetermined AC power by a power conversion device (inverter or the like) such as a power conditioner (not shown), and is supplied to a power supply destination (for example, a load facility or a power system).

101 Cell stack 103 Hypokeimenon (base)
105 Fuel cell (power generation element)
107 Interconnector 109 Fuel pole 111 Solid electrolyte 113 Air pole 115, 115a, 115b Lead part 201 SOFC module 203 SOFC cartridge 205 Pressure vessel 207 Fuel gas supply pipe 207a Fuel gas supply branch pipe 209 Fuel gas discharge pipe 209a Fuel gas discharge branch pipe 215 Power generation room 217 Fuel gas supply room 219 Fuel gas discharge room 221 Oxidizing gas supply room 223 Oxidizing gas discharge room 225a Upper pipe plate 225b Lower pipe plate 227a Upper heat insulating body 227b Lower heat insulating body 229a Upper casing 229b Lower casing 231a Fuel gas Supply hole 231b Fuel gas discharge hole 233a Oxidizing gas supply hole 233b Oxidizing gas discharge hole 235a Oxidizing gas supply gap 235b Oxidizing gas discharge gap 237a, 237b Seal member

Claims (4)

A method for manufacturing a fuel cell, which comprises a fuel electrode, a solid electrolyte, and an air electrode, and includes a plurality of power generation elements arranged along the surface of the substrate and an interconnector for connecting the adjacent power generation elements.
Slurry preparation process to prepare fuel electrode slurry, solid electrolyte slurry, interconnector slurry,
A film forming step of controlling the film forming positions of the fuel electrode slurry, the solid electrolyte slurry, and the interconnector slurry on the substrate to form the fuel electrode film, the solid electrolyte film, and the interconnector film.
A firing step of heating the substrate, the fuel electrode film, the solid electrolyte film, and the interconnector film together to obtain a sintered body.
With
In the slurry preparation step, in the preparation of at least one slurry of the fuel electrode slurry, the solid electrolyte slurry and the interconnector slurry, an oily solvent colorant is added to the slurry solvent to color the slurry.
A method for manufacturing a fuel cell, which decolorizes a color derived from the oil-based solvent colorant by heating in the firing step. The slurry solvent is a solvent containing an aromatic hydrocarbon solvent.
The method for producing a fuel cell according to claim 1, wherein the oil-based solvent colorant is a compound composed of an aromatic compound. A step of inspecting the color tone of the film containing the oil-based solvent colorant formed in the film forming step and confirming the soundness of the film based on the presence or absence of a change in the color tone from the predetermined color tone range at the initial stage of film forming is further provided. The method for manufacturing a fuel cell according to claim 2. The fuel according to any one of claims 1 to 3, further comprising a step of recognizing the surface of the substrate on which the film containing the oil-based solvent colorant is formed and confirming the formation position of the film by color tone. How to make a battery.

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