JP2007149508A - Method of manufacturing cell stack device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a cell stack device capable of preventing cracks or the like caused by the difference between thermal expansion coefficients of a cell stack and a manifold. <P>SOLUTION: The method is arranged such that a cell stack 25 formed by plurally arranging rod-shaped solid oxide fuel cell cells having a gas passage 81a in the length direction is stood and fixed to a manifold 27 in a gas sealed state, and a space inside the manifold 27 is communicated with a gas passage 31a of a solid oxide fuel cell 30. A cylindrical manifold body 27a forming part of the manifold 27 is made of an insulating inorganic material, and the cell stack 25 is stood and fixed to the manifold body 27a. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a cell stack device, and more particularly, to a method for manufacturing a cell stack device in which a cell stack formed by arranging a plurality of solid oxide fuel cells is erected and fixed to a manifold.

  In recent years, various types of fuel cells in which a plurality of solid electrolyte fuel cells are accommodated in a storage container have been proposed as next-generation energy. A solid electrolyte fuel cell is configured, for example, by sequentially forming a solid electrolyte layer and a fuel electrode layer on the surface of an oxygen electrode layer. A fuel (hydrogen) is flowed to the fuel electrode layer side, and a fuel cell is formed on the oxygen electrode layer side. Electric power is generated at about 600 to 1000 ° C. by flowing air (oxygen).

  As described above, since the solid oxide fuel cell uses two kinds of gas and is exposed to a high temperature, there are various sealing properties in the gas supply pipe and the cell so that the gas does not leak even at a high temperature. Improvements have been made. For example, conventionally, a cell stack apparatus in which an alloy gas supply pipe is joined to the side surface of an alloy gas manifold, and a support plate of the cell stack is joined to the opening of a rectangular parallelepiped gas manifold body having an upper surface opened. Known (see, for example, Patent Documents 1 and 2).

  In this fuel cell, the cell stack is configured such that a fuel cell is inserted into the cell insertion hole of an alloy support plate in which a number of cell insertion holes are formed, a glass material is filled in the gap, and the support plate is gastight. It was joined to the gas manifold in a sealed state.

In such a fuel cell, for example, a fuel gas such as hydrogen is supplied into a gas manifold via a gas supply pipe, and this fuel gas is supplied to a gas passage formed inside the fuel cell constituting the cell stack. On the other hand, air is supplied to the outside of the fuel cell, and power can be generated in the power generation unit in which the solid electrolyte layer is sandwiched between the fuel electrode layer and the air electrode layer.
JP 2005-216620 A Japanese Patent Laid-Open No. 2005-128531

  However, in the fuel cells disclosed in Patent Documents 1 and 2, the fuel cell is inserted into the cell insertion hole of the alloy support plate, the gap is filled with a glass material, and the fuel cell is alloyed with the glass material. Because it was airtightly bonded to the support plate made of glass, there is a risk that the glass material will be cracked or peeled off during production or power generation due to the difference in thermal expansion coefficient between the alloy support plate and the glass material. Was still low.

  For this reason, one end in the axial length direction of a plurality of fuel cells is integrated with a glass material, and a plurality of fuel cells are erected on a rectangular cell support plate made of a glass material to form a cell stack. It is conceivable that the stack is joined to the opening of the alloy manifold with the upper surface opened by a glass material. In this case, however, the fuel expansion is caused by the difference in the thermal expansion coefficient between the cell support plate made of the glass material and the alloy manifold. There is a possibility that cracks, peeling, etc. may occur on the cell support plate made of a glass material at the time of battery production or power generation.

  An object of this invention is to provide the manufacturing method of the cell stack apparatus which can suppress the crack etc. based on the thermal expansion coefficient difference of a cell stack and a manifold.

  The manufacturing method of the cell stack device of the present invention comprises a cell stack formed by arranging a plurality of rod-shaped solid electrolyte fuel cells having gas flow paths in the length direction, and standing and fixed in a gas-sealed state on a manifold. , A manufacturing method of a cell stack device in which a space in the manifold and a gas flow path of the solid oxide fuel cell communicate with each other, wherein a cylindrical manifold body constituting a part of the manifold is insulative inorganic The cell stack is erected and fixed to the manifold at the same time as the material is formed.

  In such a method of manufacturing a cell stack apparatus, a cylindrical manifold body constituting a part of the manifold is formed of an insulating inorganic material, and at the same time, the cell stack is erected and fixed to the manifold. In other words, the cell stack gas seal And the cylindrical manifold body are simultaneously formed of the same insulating inorganic material, the sealing material between the fuel cells and the manifold body can be integrally formed by simultaneous firing with, for example, a glass material.

  Therefore, by matching the thermal expansion coefficient of the inorganic material to the fuel cell, for example, a solid electrolyte material made of ceramic, the fuel cell constituting the cell stack, the seal material filling the gap of the fuel cell, and the manifold body, It becomes possible to form with a material having an approximate thermal expansion coefficient, and it is possible to effectively suppress cracks and the like based on the difference in thermal expansion coefficient and to easily manufacture a cell stack device. The insulating inorganic material of the present invention is meant to include ceramic and glass (including crystallized glass).

  In addition, the cell stack manufacturing method of the present invention includes a cell stack setting step in which a core is brought into contact with the lower end surface of the cell stack, and a slurry containing the insulating inorganic material around at least one side surface of the core. A molded body forming step of standing and fixing the cell stack on the cylindrical manifold body molded body, a step of firing the insulating inorganic material, and a step of drawing the core from the manifold body molded body And a child removal step. It should be noted that the core can be pulled out before firing if the manifold body molded body has a strength capable of supporting the cell stack even after the core is pulled out. Moreover, after calcining so that the manifold body molded body has a strength capable of supporting the cell stack, the core can be drawn out and fired.

  In such a method of manufacturing the cell stack device, cracks and the like based on the difference in thermal expansion coefficient can be effectively prevented, and an inorganic material is arranged around the core and the core is pulled out so that the lower end of the cell stack is cylindrical. A molded body embedded in a gas-sealed state in a cylindrical manifold body can be formed all at once, and the cell stack device in which the gas flow paths of the fuel cells constituting the cell stack communicate with the space in the manifold body can be easily achieved. Can be formed.

  Further, the manufacturing method of the cell stack device according to the present invention is characterized in that the insulation is provided around a periphery excluding at least one side surface of the core in a mold accommodated in a state where the lower end surface of the cell stack is in contact with the core. A slurry containing a conductive inorganic material is poured, and a molded body forming step of standing and fixing the cell stack to the cylindrical manifold body molded body, a step of firing the insulating inorganic material, and the core as the manifold A core removing step of drawing out from the molded body.

  In such a method of manufacturing a cell stack apparatus, a slurry containing an insulating inorganic material can be poured into a molding die to form a cylindrical manifold body molded body. Therefore, the lower end portion of the cell stack has a cylindrical manifold body molded body. A molded body embedded in a gas-sealed state can be formed all at once, and a cell stack device in which the gas flow paths of the fuel cells constituting the cell stack communicate with the space in the manifold body can be easily formed.

  In addition, the method for manufacturing a cell stack device according to the present invention includes a step of closing the opened side surface of the cylindrical manifold body with the insulating inorganic material after the core removing step. . In such a method of manufacturing a cell stack device, a manifold with closed side surfaces can be easily manufactured. In addition, when forming a side wall that closes the opening of the manifold body, a gas supply pipe to the manifold is formed at the same time, and the side wall provided with the gas supply pipe is joined to the opening of the manifold body. Thus, the cell stack device can be easily formed.

  In the manufacturing method of the cell stack device according to the present invention, a cylindrical manifold body constituting a part of the manifold is formed of an insulating inorganic material, and at the same time, the cell stack is erected and fixed to the manifold. The material and the manifold body can be formed by co-firing with the same material, for example, a glass material or a ceramic material. By adjusting the thermal expansion coefficient of the inorganic material to the fuel battery cell, the fuel battery cell constituting the cell stack, the sealing material filling the gap of the fuel battery cell, and the manifold are formed of materials having approximate thermal expansion coefficients. Thus, cracks and the like based on the difference in thermal expansion coefficient can be effectively suppressed, and a cell stack device can be easily manufactured.

  FIG. 1 shows an embodiment of a cell stack device obtained by the manufacturing method of the present invention. The cell stack device is configured by standingly fixing a cell stack 25 to a manifold 27. The cell stack 25 is configured by arranging a plurality of rod-shaped solid electrolyte fuel cells 30 having gas flow paths in the length direction.

  The fuel battery cell 30 has, for example, a flat cross section, an elliptical cylinder shape (hollow flat plate type) as a whole, and an elongated substrate shape, and a plurality of gas flow paths in the length direction thereof. It is formed to penetrate through. The fuel cell will be described later.

  In the cell stack, the fuel cells 30 are arranged in the cell thickness direction so that the side surfaces thereof are opposed to each other, and between the fuel cells 30, a current collector that electrically connects the fuel cells 30 in series. A member 33 is arranged.

  On the other hand, the manifold 27 is formed of an insulating inorganic material, for example, crystallized glass. As shown in FIG. 1B, the bottom surface of the manifold body 27a having an open side surface and the side surface of the manifold 27 are formed. The side wall forming member 27b is formed by joining the side wall forming member 27b to the opening of the manifold body 27a. The manifold body 27a has a rectangular parallelepiped shape, and a rectangular parallelepiped space is formed therein.

  A gas supply pipe 35 for supplying gas into the manifold 27 is connected to the side wall forming member 27b and integrated therewith.

  In the cell stack device, the lower end portion of the solid oxide fuel cell 30 constituting the cell stack 25 is erected integrally with the upper surface of the manifold 27 (which constitutes the top plate). That is, the lower end portion of the cell stack 25 is filled with an insulating inorganic material between the fuel cells 30, and a cylindrical manifold body 27a constituting a part of the manifold 27 is also formed of the same insulating inorganic material. Are simultaneously molded, co-fired and integrated. Therefore, the gas seal between the fuel cells 30 and the manifold body 27a are simultaneously fired and formed at the lower end of the cell stack 25 at the same time.

  In this case, as shown in FIG. 1C, the manifold body 27a may be formed so that a part of the lower end surface of the solid oxide fuel cell 30 is placed on a part of the manifold body 27a. desirable. Thereby, even when the temperature becomes high during power generation and the inorganic material is softened (the gas seal material between the fuel cells 30 is softened), the downward shift of the fuel cells 30 can be prevented.

  The side wall forming member 27b is also formed of the same inorganic material, and is formed and fired in a state where one end of the gas supply pipe 35 is embedded, and the side wall forming member 27b is an opening of the manifold main body 27a. Are joined with the same inorganic material.

  The cell stack device configured as described above can be manufactured as shown in FIG. In FIG. 2, a part of the fuel cell 30 is omitted, and a part of the current collecting member is also omitted.

  First, as shown in FIG. 2A, a bottomed rectangular parallelepiped manifold main body mold 51 having an open top surface is prepared. A through-hole 52 for entering and exiting the core 53 is formed on one side wall of the main body mold 51, and the core 53 is inserted through the through-hole 52 on the side wall of the main body mold 51 to form the main body mold. A part of the core 53 protrudes outside the main body mold 51. In addition, a through-hole may be formed in each of the opposing side walls of the main body mold 51, and the core may be inserted. In this case, the core 53 can be stably arranged. In this case, it is necessary to close both sides of the manifold body 27a with the side wall forming members 27b.

  The main body mold 51 is formed of a material that absorbs the solvent of the slurry and has poor wettability, such as a ceramic fiber molded body, and the core 53 is also formed of the same material. Yes. The core 53 forms a space inside the manifold main body 27 a, and the shape of the internal space of the manifold main body 27 a is determined by the shape of the core 53. For example, if the core is cylindrical, the inner space of the manifold main body 27a is also cylindrical by arranging the core 53 in the main body mold 51 and pouring slurry.

  Thereafter, the lower surface of the cell stack 25 is placed in contact with the upper surface of the core 53. That is, the lower surfaces of the plurality of fuel cells 30 constituting the cell stack 25 are brought into contact with the upper surface of the core 53. In order to place the fuel cell 30 on the core 53, the current collectors 33 arranged and arranged between the fuel cells 30 are fixed in advance, and the lower end surface thereof is placed on the core 53. Is desirable.

  Then, as shown in FIGS. 2B and 2C, between the main body mold 51 and the core 53, an insulating inorganic material such as crystallized glass or ceramic powder, an organic binder, After pouring a slurry containing an organic component such as a solvent until at least the upper surface of the core 53 is covered, the slurry is left to stand or dried at a temperature of about 100 ° C. in a dryer to volatilize the solvent, and then fired. To do. In the case of ceramic powder, the firing temperature is fired at a temperature equal to or higher than the sintering temperature of ceramics. In the case of glass powder, the firing temperature is higher than the glass softening point. In the case of crystallized glass powder, the firing temperature is higher than the crystallization temperature.

  Thereafter, as shown in FIGS. 2C and 2D, after the core 53 is pulled out from the through hole 52, the main body mold 51 is removed, and the upper surface of the manifold main body 27a is removed as shown in FIG. The lower end of the cell stack 25 is integrally formed.

  In addition, after calcining to such an extent that the manifold body molded body can be handled, the core 53 may be pulled out, the body molding die 51 may be removed, and then fired. Alternatively, it can be formed by pouring the slurry into the main body mold 51 in which the through holes 52 are not formed, placing the core 53 on the slurry, and then pouring the slurry around the core 53 again. .

  A process of closing the opened side surface of the cylindrical manifold body 27a with an insulating inorganic material will be described. First, a side wall member forming die 71 having a shape matching the opened side surface of the manifold body 27a is prepared, and a gas supply pipe 35 made of a heat-resistant metal is inserted into the through hole of the side wall member forming die 71. After the slurry is poured into the side wall member forming mold 71, cured, and baked, the side wall member forming mold 71 is removed to form the side wall forming member 27b through which the gas supply pipe 35 is inserted.

  Then, as shown in FIG. 1 (c), the side wall forming member 27b is brought into contact with the opening of the manifold body 27a through the paste containing the inorganic material and heat-treated, so that the cell as shown in FIG. Stack devices can be made.

  In addition, as a material of the main body shaping | molding die 51, the core 53, and the side wall member formation type | mold 71, the thing which is easy to absorb the solvent of a slurry and consists of material with poor wettability with a slurry is desirable. This is because if the solvent is easily absorbed, the raw material powder in the slurry can be filled more easily, cracking during drying and firing hardly occurs, a strength is high, and a manifold excellent in gas sealability can be obtained. In addition, when the wettability is poor, the restraining force accompanying the shrinkage during drying and firing becomes weak, so that it is difficult to break. A ceramic heat insulating material is preferable as such a material. This ceramic heat insulating material is also excellent in high temperature resistance, can be fired together with the slurry, and can be easily removed after firing, thus facilitating the process. As the ceramic heat insulating material, a heat insulating material made of alumina fiber or alumina-silica fiber is preferable from the viewpoint of ease of processing and cost.

  As the slurry containing an insulating inorganic material, crystallized glass is preferable from the viewpoint of sealing properties and high temperature deformation resistance. In this case, the baking is performed by heating at a temperature equal to or higher than the softening point temperature of the crystallized glass so as to have integral molding and a sealing function matched to the mold, and then crystallization is performed at a temperature higher than the crystallization temperature. The crystallized glass to be used is not particularly limited as long as it has a thermal expansion close to that of the cell stack, but a borosilicate glass-based crystallized glass can be suitably used from the viewpoint of high temperature resistance.

  The fuel cell used in the present invention will be described. As shown in FIG. 1, the fuel battery cell has a hollow flat plate shape, a flat cross section, and a porous support substrate (support) 81 having a rod shape and an elongated substrate shape as a whole. Inside the support substrate 81, six fuel gas passages 81a (forming gas passages) are formed penetrating in the length direction (axial length direction) at appropriate intervals. The support substrate 31 has a structure in which various members are provided. A plurality of such fuel battery cells 30 can be arranged in a line as shown in FIG. 1 to form a cell stack.

  The support substrate 81 includes a flat portion A and arc-shaped portions B at both ends of the flat portion A, and the flat portion A constitutes a main surface. Both main surfaces of the flat portion A are formed substantially parallel to each other, and a fuel electrode layer 82 is provided so as to cover one main surface of the flat portion A and the arc-shaped portions B on both sides, and further covers the fuel electrode layer 82. Thus, a dense solid electrolyte layer 83 is laminated, and an oxygen electrode layer 84 is formed on the main surface on one side of the flat portion A so as to face the fuel electrode layer 82 on the solid electrolyte layer 83. Are stacked. The fuel electrode layer 82 and the solid electrolyte layer 83 are formed continuously on the main surface on one side of the flat portion A in the gas flow path forming direction G.

  Further, an interconnector 85 is formed on the other main surface of the flat portion A where the fuel electrode layer 82 and the solid electrode layer 83 are not stacked. As is clear from FIG. 4, the fuel electrode layer 82 and the solid electrolyte layer 83 extend to both sides of the interconnector 85 and are configured so that the surface of the support substrate 81 is not exposed to the outside.

  In the fuel cell having the above structure, the portion of the fuel electrode layer 82 facing the oxygen electrode layer 84 operates as a fuel electrode to generate electric power. That is, an oxygen-containing gas such as air is allowed to flow outside the oxygen electrode layer 84, and a fuel gas (hydrogen) is supplied to the gas passage 81a in the support substrate 81, and the oxygen electrode layer 84 is heated to a predetermined operating temperature. Then, an electrode reaction of the following formula (1) is generated, and power is generated by generating an electrode reaction of the following formula (2), for example, in the portion that becomes the fuel electrode of the fuel electrode layer 82.

Oxygen electrode: 1 / 2O ₂ + 2e ⁻ → O ²⁻ (solid electrolyte) (1)
Fuel electrode: O ²⁻ (solid electrolyte) + H ₂ → H ₂ O + 2e ⁻ (2)
The current generated by such power generation is collected via an interconnector 85 attached to the support substrate 81.

  In addition, this invention is not limited to the said form, A various change is possible in the range which does not change the summary of invention. For example, in the above embodiment, the flat fuel cell 80 having a plurality of gas flow paths 81a as shown in FIG. 4 has been described, but a cylindrical fuel cell may be used.

  Further, in the present invention, the example in which the opening on the side surface of the manifold body 27a is closed with the side wall forming member 27b has been described. The manifold can also be manufactured by pulling out the core from this opening and closing it with the bottom surface forming member.

1 shows a cell stack device obtained by the manufacturing method of the present invention, where (a) is a sectional view, (b) is a partially exploded perspective view, and (c) is a lower end surface of a fuel cell supported by a manifold. It is sectional drawing which shows a state. It is process drawing for demonstrating the manufacturing method of the cell stack apparatus of this invention. (A) is sectional drawing for demonstrating the manufacturing method of a side wall formation member, (b) is sectional drawing which shows the state by which the gas supply pipe | tube is joined to the side wall member. The fuel cell is shown, (a) is a cross-sectional view, (b) is a vertical cross-sectional view.

Explanation of symbols

25 ... Cell stack 27 ... Manifold 27a ... Manifold body 27b ... Side wall forming member 30 ... Fuel cell 51 ... Main body mold 53 ... Core 81a ... Fuel gas Flow path

Claims (4)

A cell stack formed by arranging a plurality of rod-shaped solid electrolyte fuel cells having gas passages in the length direction is vertically fixed in a gas-sealed state to the manifold, and the space in the manifold and the solid electrolyte A method of manufacturing a cell stack device in which a gas flow path of a fuel cell of a fuel cell communicates, wherein a cylindrical manifold body constituting a part of the manifold is formed of an insulating inorganic material, and at the same time the cell stack is formed A method of manufacturing a cell stack device, wherein the device is vertically fixed to the manifold body. A cell stack setting step in which a core is brought into contact with the lower end surface of the cell stack, and a slurry containing the insulating inorganic material is arranged around at least one side surface of the core to form the cylindrical manifold body A molded body forming step of standingly fixing the cell stack to the body, a step of firing the insulating inorganic material, and a core removing step of drawing the core from the manifold body molded body. The method of manufacturing a cell stack device according to claim 1. Slurry containing the insulating inorganic material is poured into a molding die accommodated in a state where the lower end surface of the cell stack is in contact with the core, except for at least one side surface of the core. A molded body forming step of standing and fixing the cell stack to a shaped manifold body molded body, a step of firing the insulating inorganic material, and a core removing step of drawing the core from the manifold body molded body. The method of manufacturing a cell stack device according to claim 1. 4. The method of manufacturing a cell stack device according to claim 2, further comprising a step of closing the opened side surface of the cylindrical manifold body with the insulating inorganic material after the core removing step. .

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