JP2005019240A - Fuel cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inexpensive fuel cell easy to assemble and maintain, and excellent in reliability, by electrically connecting a plurality of cell stacks with a simple structure. <P>SOLUTION: This cell stack 1 is equipped with a plurality of fuel cells 5 having gas passages 13, collecting members 7 interposed between the fuel cells 5, and a gas tank 3 supporting the fuel cells 5 to supply a gas to the gas passages 13, and a plurality of the cell stacks are arranged and stored in a storage vessel to form this fuel cell. The fuel cell 5 positioned at the end of the cell stack 1 is electrically connected to the fuel cell 5 at the end of another adjacent cell stack 1 by a cell stack connecting member 9, and the cell stack connecting member 9 is fixed to the cell stack 1. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a fuel cell, and more particularly to a method for fixing and collecting a fuel cell stack.
[0002]
[Prior art]
In recent years, various fuel cells in which a stack of fuel cells is accommodated in a storage container have been proposed as next-generation energy.
[0003]
A fuel cell is configured by sandwiching a solid electrolyte between an air electrode and a fuel electrode, supplying an oxygen-containing gas to the air electrode, and supplying a gas containing hydrogen or a gas capable of changing to hydrogen to the fuel electrode. A potential difference is generated between both electrodes facing each other across the solid electrolyte, and power is generated.
[0004]
These fuel cells can be used in various combinations depending on the electrolyte and form used, but in most cases, the fuel cell is supplied with a gas containing oxygen and a gas containing hydrogen or a gas that can be changed to hydrogen to generate power. Do.
[0005]
In addition, since the amount of power generated per fuel cell is small, the fuel cell is configured by electrically coupling a plurality of fuel cells. Furthermore, the generated direct current electricity is converted into alternating current electricity to be supplied to demand equipment. In order to increase the conversion efficiency and reduce the power loss due to the electrical resistance during current collection, the fuel cells are connected in series. It is desirable to increase the voltage generated from the cell stack by coupling to.
[0006]
In such a fuel cell, since power is generated at a high temperature of about 1000 ° C., a plurality of fuel battery cells or a plurality of cell stacks are connected due to a change in member dimensions due to heat or deterioration of the member, and the connection reliability thereof is determined. It was difficult to maintain sex.
[0007]
Therefore, an attempt has been made to improve the connection reliability by pressing the current collecting members on both sides of the fuel cell stack to make an electrical connection and taking out the electric power to the outside through the current collecting plate (patent). Reference 1).
[0008]
[Patent Document 1]
JP-A-1996-162146
[Problems to be solved by the invention]
However, in such a fuel cell, the anode-side and cathode-side current collector plates are pressed by a furnace wall inserted into the side of the power generation chamber, a heat insulating material, or an elastic clamping member to Although the connection is made, there is a problem that the structure for pressing the fuel cell stack becomes complicated, and it is difficult to increase the voltage because the fuel cells are connected in series and parallel. Further, in order to increase the voltage, it is necessary to further connect the series of fuel cell stacks connected in series and parallel, and there is a problem that the number of cells used increases.
[0010]
In order to solve the above problems, an object of the present invention is to provide a fuel cell capable of connecting a plurality of fuel cells and a plurality of fuel cell stacks with a simple structure.
[0011]
[Means for Solving the Problems]
The fuel cell of the present invention supports a plurality of fuel cells having gas flow paths, a current collecting member interposed between the fuel battery cells, and supports the fuel battery cells, and supplies gas to the gas flow paths. A plurality of cell stacks each having a gas tank for storing the fuel cell, and a fuel cell located at the end of the cell stack and a fuel cell at the other end of the cell stack, The cell stack connection members are electrically connected to each other, and the cell stack connection members are fixed to the cell stack.
[0012]
In such a fuel cell, by fixing the cell stack connection member to the end of the cell stack, it is possible to apply pressure in the connection direction between the cells in the cell stack with a simple structure, thus ensuring the connection between the cells. In addition, since the electrical connection between the cell stacks can be secured, the number of parts can be reduced, the assemblability can be improved, and the connection reliability can be improved.
[0013]
In addition, for example, by fixing the cell stack connecting member to the gas tank of the cell stack, it is not necessary to separately provide a jig or member for pressing the cell stack connecting member against the fuel cell. In addition, electrical connection within the cell stack and between the cell stacks can be secured. Further, since the cell stack and the cell stack connecting member can be easily connected and detached, the assembling property and the maintenance property can be improved.
[0014]
In the fuel cell of the present invention, the current collecting member is plate-shaped and has a shape having elasticity in the direction between the fuel cells. In this way, by making the current collecting member in a relatively high rigidity form, for example, even if a heat cycle is applied, the elasticity of the current collecting member hardly changes, and in a form with a small surface area, Oxidation or corrosion of the current collecting member is suppressed by the influence of the atmosphere, changes in rigidity and elasticity of the current collecting member can be suppressed, and the connection of the fuel cells is well maintained over a long period of time.
[0015]
Moreover, the fuel cell of the present invention is characterized in that the cell stack connecting member is made of conductive ceramics or metal. Thus, current collection loss can be reduced by using a highly conductive metal for the cell stack connection member. Moreover, by using conductive ceramics, the oxidation resistance is improved and the connection reliability is improved.
[0016]
In the fuel cell of the present invention, the cell stack connecting member includes a conductive portion and a non-conductive portion, and the conductive portion is connected to the fuel cell at the end of the cell stack and the fuel cell at the end of the adjacent cell stack. The non-conductive portion is made of ceramics.
[0017]
In this way, by configuring the cell stack connection member with a conductive part having excellent conductivity and a non-conductive part made of ceramics having excellent strength and heat resistance as a structural member, the electrical resistance can be lowered. Thus, a highly reliable fuel cell capable of suppressing deformation and deterioration due to heat is obtained.
[0018]
In the fuel cell of the present invention, the cell stack connecting member fixes the fixing member fixed to the cell stack and the other fixing member fixed to the adjacent cell stack with the connecting member that electrically connects. It is characterized by.
[0019]
In this way, the cell stack connection member has a split structure to improve the ease of manufacturing, and even if the cell stack connection member is exhausted and needs to be replaced, it is necessary to replace the necessary components. This will reduce the running cost.
[0020]
In the fuel cell according to the present invention, the fixing member includes a conductive portion and a nonconductive portion, the conductive portion is connected to a fuel cell, and the nonconductive portion is made of ceramics.
[0021]
By constructing a cell stack connection member with a conductive part with excellent conductivity and a non-conductive part made of ceramics with excellent strength and heat resistance as a structural member, a fuel cell with low electrical resistance and high reliability can be obtained. Become. In addition, since the cell stack connection member has a divided structure, the ease of manufacturing is improved, and only the parts that need to be replaced are required, so that the running cost is reduced. Furthermore, by using such a structure and subdividing the members, an optimal material can be selected for each member, and a fuel cell having excellent characteristics can be provided.
[0022]
The fuel cell of the present invention is characterized in that the connecting member is made of a conductive wire or square. By using a conductive wire rod or square rod excellent in productivity and workability, the member can be supplied at low cost, so that it is possible to provide a fuel cell that is inexpensive and low in running cost.
[0023]
In the fuel cell of the present invention, the cell stack connecting member and the gas tank are fixed by an adhesive and / or screws. By adopting such a connection structure, it is possible to provide a fuel cell excellent in connection reliability, assemblability, and maintainability.
[0024]
The fuel cell of the present invention is characterized in that the fixing member and the connecting member are fixed by a conductive adhesive and / or a screw. By adopting such a connection structure, it is possible to provide a fuel cell excellent in connection reliability, assemblability, and maintainability.
[0025]
DETAILED DESCRIPTION OF THE INVENTION
The fuel cell of the present invention is formed, for example, by storing a cell stack 1 as shown in FIGS. 1 and 2 in a storage container. FIG. 1 is a longitudinal sectional view of the cell stack 1 and a cell stack connecting member 9. FIG. 2 shows a connection structure of a plurality of cell stacks 1.
[0026]
In the cell stack 1 of the fuel cell according to the present invention, a plurality of fuel cells 5 are erected on a gas tank 3, and these fuel cells 5 are electrically connected with a current collecting member 7 between the fuel cells 5. Connected and configured. The fuel cell 5a and the fuel cell 5h arranged at the end of the cell stack 1 are pressed from both sides by the cell stack connecting member 9, and the cell stack connecting member 9 is made of an adhesive (not shown) and / or Alternatively, it is fixed to the gas tank 3 by a screw 11.
[0027]
The cell stack connecting member 9 includes a fixing member 9a and a connecting member 9b, and the fixing member 9a of the cell stack connecting member 9 is fixed to the gas tank 3 as shown in FIG. As shown in FIG. 2, the connection member 9b electrically connects the fuel cell 5a at the end of the cell stack 1a to the fuel cell 5i at the end of the cell stack 1b.
[0028]
Thus, by fixing the cell stack connection member 9 to the gas tank 3, the cell stack 1a and the cell stack 1b can be reliably electrically connected with a simple structure as compared with the conventional connection structure.
[0029]
These fuel cells 5 include, for example, a power generation unit that has a gas flow path 13 therein and is formed by sequentially laminating an internal electrode, a solid electrolyte, and an external electrode (not shown). In addition, the detailed detailed structure of the fuel cell 5 was abbreviate | omitted.
[0030]
The lower end portions of these fuel cells 5 are supported and fixed to the upper lid 3 a of the gas tank 3 that also serves as a support for the fuel cells 5.
[0031]
In a fuel cell in which a plurality of such cell stacks 1 are housed in a housing container, the inside of the housing container is heated to heat the fuel cell 5 to a predetermined temperature, and from the upper lid 3a and the gas tank frame 3b. A hydrogen-containing gas is supplied to the gas chamber 15 in the gas tank 3, and the fuel gas and / or the oxygen-containing gas is supplied to the gas flow path 13 in the fuel cell 5 through the gas introduction path 17 provided in the upper lid 3 a. Is generated, and oxygen-containing gas and / or fuel gas is supplied between the fuel cells 5 to generate power.
[0032]
During power generation, the current generated in the fuel cells 5 flows through the current collecting member 7 and the cell stack connecting member 9 provided between the fuel cells 5 and is used.
[0033]
In such a fuel cell, it is important that one end of the cell stack connecting member 9 is fixed to the gas tank 3, and various other forms can be taken.
[0034]
Various forms of the cell stack connection member 9 will be described below with reference to FIGS. 3 to 8, (a) is a cross-sectional view of the broken line part of (b), and (b) is an explanatory view as viewed from the side A of the cell stack connecting member 9 in contact with the fuel cell 5, (C) is explanatory drawing seen from the reverse side B of the side which contacts the fuel cell 5 of the cell stack connection member 9. FIG.
[0035]
For example, as shown in FIG. 3, the cell stack connection member 9 is a single body, and in a form made of conductive ceramics or heat-resistant metal, the cell stack connection member 9 can be easily manufactured and the number of parts can be reduced. Manufacturing cost can be reduced.
[0036]
As shown in FIG. 4, when the cell stack connecting member 9 is composed of a non-conductive part (fixing member 9a) made of ceramics and a conductive part (connecting member 9b), the non-conductive parts made of ceramics. Since the portion 9a can maintain high rigidity even at a high temperature, a good pressing force can be applied to the fuel cell 5 even during power generation. In addition, since the area where the conductive portion 9b is in contact with the gas is reduced, deterioration of the conductive portion 9a can be suppressed. In such a form, the conductive portion 9b and the non-conductive portion 9a may be bonded together by, for example, a conductive adhesive containing a metal selected from Ag, Pt, and Au, and simultaneously sintered. It is good also as an integral thing. Further, when the non-conductive portion (fixing member 9a) and the conductive portion (connecting member 9b) are mechanically fixed by using a screw or the like, if each member is temporarily damaged, It is possible to release the fixing and replace only the damaged parts, thereby reducing the running cost.
[0037]
In addition, as shown in FIG. 5, when the conductive fixing member 9a of the cell stack connection member 9 is divided into a plurality of parts, the number of parts increases, so that the connection structure is slightly complicated. Even if there is a slight dimensional difference in 1, the dimensional difference can be absorbed by the connecting portion, so that assembly is facilitated. Moreover, even if some parts are damaged, by exchanging only those parts, it can be easily repaired and the running cost can be reduced.
[0038]
As shown in FIG. 6, when the insulating fixing member 9a of the cell stack connecting member 9 is divided into a plurality of parts and the fixing member 9a is made of ceramics, in addition to the points described in FIG. Since 9a is a highly rigid ceramic, there is an advantage that the cell stack 1 can be satisfactorily held even at a high temperature, and long-term reliability is improved.
[0039]
Further, as shown in FIG. 7, the fixing member 9a of the cell stack connection member 9 is divided into a plurality of parts, and the fixing member 9a further includes a non-conductive part 9a1 made of ceramics and a conductive part surrounding the outer periphery of the non-conductive part 9a1. In the form in which the fixing member 9a is electrically connected by the connecting member 9b, since the conductive portion 9a2 surrounds the non-conductive portion 9a1 made of ceramics, even if the two materials are different, , Peeling is unlikely to occur and connection reliability is improved.
[0040]
Also, as shown in FIG. 8, for example, when the connecting member 9b in FIG. 7 is replaced with a square member, the connecting member 9b can be easily obtained, and the manufacturing cost can be reduced. Further, since the rigidity of the connection member 9b is reduced, it becomes easy to absorb the deformation of the cell stack 1 due to the thermal cycle and the reliability is improved.
[0041]
It is important that the current collecting member used in the fuel cell of the present invention has a plate shape as shown in FIG. 9 and is bent so as to have elasticity in the direction between the fuel cells. Such a shape is realized by, for example, an N-type shape as shown in FIG. 9A or a comb-teeth shape as shown in FIG. The direction of the arrow shown in FIG. 9 is the direction between the fuel cells 5.
[0042]
In the current collecting member 7 having such a shape, elasticity and rigidity are not easily changed even by a thermal cycle, and plastic deformation hardly occurs as compared with a conventional felt or the like. Therefore, the combination with the cell stack connection member 9 of the present invention is particularly effective.
[0043]
The fuel cell of the present invention is obtained by housing the connection structure of the cell stack 1 and the cell stack connection member 9 described above in a storage container.
[0044]
Of course, in the fuel cell described above, the connecting member 9b has conductivity.
[0045]
The fuel cell of the present invention is not limited to the above example, and can be modified without departing from the gist of the present invention.
[0046]
【The invention's effect】
According to the present invention, the cell stack connecting member is fixed to the end of the cell stack, and one cell stack and the other cell stack are electrically connected to each other, thereby having a simple structure, assembling property, maintainability and reliability. An excellent fuel cell can be provided.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing a connection structure of a cell stack and a cell stack connecting member according to the present invention.
FIG. 2 is a diagram showing a connection structure between the cell stack and the cell stack connection member of FIG. 1;
FIG. 3 is an explanatory view of an embodiment of an integral cell stack connecting member used in the fuel cell of the present invention.
FIG. 4 is an explanatory view of a cell stack connecting member having a conductive portion and a non-conductive portion used in the fuel cell of the present invention.
FIG. 5 is an explanatory view of a cell stack connecting member having a divided structure used in the fuel cell of the present invention.
FIG. 6 is an explanatory diagram of a cell stack connecting member having a divided structure and including a conductive portion and a non-conductive portion.
FIG. 7 is an explanatory view of another form of the cell stack connecting member having a divided structure and having a conductive portion and a non-conductive portion.
FIG. 8 is an explanatory view of a cell stack connecting member having a divided structure and having a connecting portion made of a wire or a square.
9A and 9B show a plate-shaped current collecting member used in the fuel cell of the present invention, in which FIG. 9A is an N-type current collecting member, and FIG. 9B is a perspective view of a comb-shaped current collecting member.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Cell stack 3 ... Gas tank 5 ... Fuel cell 7 ... Current collecting member 9 ... Cell stack connection member 9a ... Fixed member 9b ... Connection member (conductive member)
11 ... Screw 13 ... Gas flow path

Claims (9)

A plurality of fuel cells having gas flow paths, a current collecting member interposed between the fuel battery cells, and a gas tank that supports the fuel battery cells and supplies gas to the gas flow paths A plurality of cell stacks arranged in a storage container, and the fuel cell located at the end of the cell stack and the fuel cell at the other adjacent cell stack end are respectively connected by a cell stack connecting member. A fuel cell characterized by being electrically connected and fixing the cell stack connecting member to the cell stack. 2. The fuel cell according to claim 1, wherein the current collecting member has a plate shape and has a shape having elasticity in a direction between the fuel cells. 3. The fuel cell according to claim 1, wherein the cell stack connecting member is made of conductive ceramics or metal. The cell stack connecting member includes a conductive portion and a non-conductive portion, the conductive portion is connected to a fuel cell at a cell stack end and a fuel cell at an adjacent cell stack end, and the non-conductive portion is made of ceramics. The fuel cell according to any one of claims 1 to 3, wherein: The cell stack connecting member is formed by fixing a fixing member fixed to a cell stack and another fixing member fixed to an adjacent cell stack with a connecting member that electrically connects. The fuel cell according to any one of 1 to 4. The fuel cell according to claim 5, wherein the fixing member includes a conductive portion and a nonconductive portion, the conductive portion is connected to a fuel cell, and the nonconductive portion is made of ceramics. The fuel cell according to claim 5 or 6, wherein the connecting member is made of a conductive wire or square. The fuel cell according to any one of claims 1 to 7, wherein the cell stack connecting member and the gas tank are fixed by an adhesive and / or screws. 9. The fuel cell according to claim 5, wherein the fixing member and the connecting member are fixed by a conductive adhesive and / or a screw.

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