JPH0260062A - Stacked fuel cell - Google Patents

Abstract

PURPOSE:To make manufacture easy, to make size compact, and to enhance safety by mutually connecting cathodes and anodes respectively with conductors passed through passing through holes of frames, and forming a sealing part between adjacent frames by stacking before-baking alumina, then baking it. CONSTITUTION:A unit cell is formed by assembling a cathode 12 and an anode 11 with an electrolyte material 13 interposed in a frame 14. A plurality of unit cells are stacked so that electrodes having the same polarity are faced and fuel manifolds 45a, 45b are formed between electrode plates. The flame 14 is formed by stacking before-baking alumina, then baking it. Bus bars 37, 38 made of soft conductive material are inserted into through holes for cathode and anode bus bars so as to connect electrode plates to taken out electric energy. A sealing part 32 is arranged between adjacent frames of unit cells to prevent leakage of reaction gases inside and outside a fuel cell. A stacked fuel cell whose safety is enhanced, size is compact, and manufacture is easy is obtained.

Description

[Detailed description of the invention] A. Industrial application field The present invention relates to a stacked fuel cell.

B9 Summary of the Invention The present invention incorporates an electrolyte object and an anode and a cathode electrode plate located on both sides of the electrolyte object into a frame member, and a plurality of single cells are arranged so that the electrode plates of the same polarity face each other and ,
After laminating the electrode plates of the same electrode so as to form a fuel manifold respectively, through holes for an anode conductor and a cathode conductor are formed in the frame member, and conductors are provided in these through holes. , by connecting the anode conductor to the anode electrode and the cathode conductor to the cathode electrode, providing a sole between adjacent frame members, and laminating unfired alumina and then firing to form the frame member. To obtain a fuel N pond that can be easily miniaturized and has excellent safety.

C1 Conventional technology The main body of a fuel cell consists of a unit cell (single cell) by arranging anode and cathode electrode plates on both sides of a solid electrolyte, and several of these single cells are stacked in series. . A plurality of these single cells are arranged so that the anode electrodes and the cathode electrode plates face each other. Hydrogen gas (hydrogen) is supplied as a fuel to the cathode plate side, and air is supplied as an oxidant to the anode plate side. (oxygen) is supplied to cause hydrogen to react with oxygen to generate electricity and water.

That is, the fuel cell main body 10, as shown in FIG.
A plurality of unit batteries (single cells S) and a holding plate 1a that stacks and fixes these single cells S in series.

1b, a hydrogen gas supply manifold 2 that supplies hydrogen gas H7 to the cathode plate side of each unit cell S of the stacked and fixed battery body IO, an air supply manifold 3 that supplies air to the anode plate side, and each unit It is composed of current collecting leads 4 and 5 that take out electricity from the anode plate and cathode plate of the cell S, respectively.

In such a stacked fuel cell, the gas supply manifold 2.3 is attached to the outside of the cell main body IO. In addition, water and electrical energy are generated by the reaction between the supplied hydrogen gas and air via the electrolyte, and the current collector lead (busbar) 4.5 that takes out the generated electrical energy is also placed outside the cell. attached to.

D9 Problems to be solved by the invention In conventional stacked fuel cells, the problem is as follows! As a challenge,
Since the manifold and bus bar were attached to the outside of the cell, the overall structure of the fuel cell itself became large, and the work when stacking a plurality of single cells was complicated.

However, Japanese Patent Laid-Open Publication No. 17781/1984 does not incorporate the idea of arranging a gas supply manifold within the cell frame and downsizing the entire structure of the cell accordingly. However, it has not been done up to now to embed a busbar within the frame of the cell for extracting the electrical energy collected by the current collector to the outside because it would make the connection between the current collector and the busbar complicated.

The second issue with stacked fuel cells is that the insulating frame plate around the cell periphery must (1) withstand thermal cycles; (2)
The material must satisfy properties such as gas sealing properties at the interface with the electrolyte, (3) insulation properties, and resistance to redox reactions.

The third issue is that the cathode and anode electrode plates are arranged on both sides of the electrolyte, hydrogen gas is supplied to the cathode side, and air is supplied to the anode side, which prevents leakage of reaction gases inside and outside the battery. It is important to.

In other words, if a gas leak occurs, it will not only reduce the power generation efficiency of the fuel cell, but also lead to a major disaster such as an explosion, so to prevent gas leaks, sufficient care must be taken when stacking single cells together. I have to pay it.

The present invention has been made in view of the above-mentioned conventional problems, and its purpose is to stack unfired alumina and then fire it to form a frame member of a single cell in a stacked fuel cell. By providing a through hole for the bus bar inside, inserting a bus bar that connects to the current collector of each cell after stacking the single cells, and forming an effective seal between the frame members of each adjacent cell. An object of the present invention is to provide a stacked fuel cell that is easy to manufacture and can be miniaturized.

E9 Means for Solving the Problems In order to achieve the above object, the present invention incorporates an electrolyte object and anode and cathode electrode plates located on both sides of the electrolyte object into a frame member to form a single cell. In a fuel cell in which a plurality of single cells are stacked so that the anode electrode plates and the cathode electrode plates face each other, and a fuel manifold is formed between each of the same electrode plates, The frame member is formed by laminating and firing alumina, and a through hole for an anode bus bar and a through hole for a cathode bus bar are formed in this frame member, and the anode plate is formed in the through hole for the anode bus bar. An anode bus bar made of a soft conductive material is provided to connect with the
A cathode busbar formed from a soft conductive material is provided in the through hole for the cathode busbar so as to be connected to the cathode plate, and a seal portion is interposed between adjacent frame members of the single cell. Configure a fuel cell.

F. When the anode busbar is inserted into the anode busbar through hole formed in the working frame member, the anode busbar is connected to the anode plate, and the cathode busbar is inserted into the cathode busbar through hole also formed in the frame member. When inserted, the cathode bus bar is connected to the cathode plate. Therefore, electrical energy is extracted through each busbar provided within the rod member. Also,
Gas sealing performance is ensured by the seal member disposed between adjacent frame members.

G. Examples Examples of the present invention will be described below with reference to FIGS. 1 to 5.

3 is a plan view of the fuel cell main body 10 according to each embodiment of the present invention, FIG. 1 is a sectional view taken along line I-I in FIG. 3, and FIG.
FIG. 4 is a sectional view taken along the line ■-■ in the figure, and shows an exploded view of a cell constituting a fuel cell main body according to an embodiment of the present invention.

In FIGS. 1 to 5, 11 is a cathode plate made of platinum or the like (
TL electrode plate, 12 is an anode plate (electrode plate) also made of platinum or the like, and 13 is, for example, yttrium.

It is a solid electrolyte object made of stabilized zirconia, lanthanum fluoride, etc. in which oxides such as calcium 7ium are dissolved in zirconia. These cathode plates 11. Anode plate 12. The solid electrolyte object 13 is assembled into the frame member 14 and the single cell S
It consists of A cathode-side current collector 15 and an anode-side current collector 16 made of metal mesh, such as nickel mesh, are installed on the cathode plate 11 and anode plate 12, respectively.

Cathode plate 11. Anode plate 12. Solid electrolyte object 13 cathode side current collector 15. Corners 17 facing each other of the frame member 14 incorporating the anode side current collector 16. +8, as shown in FIG. 4, is provided with a manifold 19.20 for a hydrogen gas flow path, and groove-shaped channels 21.22 are provided in each of the manifolds 19.20,
The cathode plate 11 and the manifold 19.20 are in communication.

The remaining mutually opposite corners 23, 24 of the frame member 14 are provided with manifolds 25, 26 for air flow paths, and groove-like channels 27, 28 are provided in each case, and the anode plate 12 and the manifold 25, 24 are provided with groove-like channels 27, 28. 26 are in communication.

Furthermore, a through hole 29 for a cathode bus bar is provided in one side 14a of the frame member 14, and a part of the cathode current collector 5 projects into this bus bar through hole 29. Further, the other side 14b of the frame member 14 is provided with an anode side bus bar through hole 30, and a part of the anode side current collector 16 protrudes into this anode side bus bar through hole 30.

More specifically, as shown in FIG. 1, the frame member 14 is a hollow plate-shaped frame plate 14a, 14b made of unfired alumina having an annular protrusion, and a hollow frame plate 14c is sealed with a glass seal 43. The negative electrode plate 11 and the current collector plate 15 are arranged between the frame plates 14a and 14c, and the positive electrode plate 1 is arranged between the frame plates 14b and 14c.
2 and a current collector plate 16, and a solid electrolyte body 13 is interposed between the electrode plates 11 and 12 to constitute a single cell S.

A plurality of single cells S are stacked and these are connected to end plates 33a, 33.
b, holding plates 34a and 34b, bolts 35 and nuts 36 to stack and fix. When these single cells S are stacked and fixed, a hydrogen gas manifold 45a is formed between the negative electrode plate II side, an air manifold 45b is formed between the positive electrode plate I2 side, and a cathode busbar A through hole 39 and a through hole 40 for an anode bus bar are formed, and conductive paste is applied to these through holes 39 and 40.

A soft conductive material such as aluminum die-casting and low-temperature Ro-H (e.g., phosphorized copper solder, brass solder) is press-fitted to form the cathode bus bar 37 and the anode bus bar 38.

When the conductive paste is press-fitted into the busbar through-holes 39.40 to form the busbars 37.38, the conductive paste is heated to a temperature higher than its melting point and liquefied before being press-fitted. Therefore,
The frame material of the cell is required to be a material that does not undergo any deformation at a temperature higher than the melting point of the conductive paste and under pressure during press-fitting. In addition, the single cells must be sealed together so that the conductive paste does not leak into areas other than the busbar through holes 39 and 40 during press-fitting.

Alumina (AQ) is a frame material that satisfies these performances.
Oxide ceramics such as zOs), zirconia, mullite, and magnesia are used. In addition, the recess 3 formed in the frame member is used as a sealing means when stacking cells.
, a and the convex portion 31b are fitted together to form a seal portion 32.

Furthermore, when the single cells S are stacked and fixed together, as shown in FIG.
is formed. Hydrogen gas flow path 4! communicates with channel 2I, and air flow passage 42 communicates with channel 22.

The original purpose of the seal between single cells is to prevent gas leaks such as fuel and oxidizer, and this seal eliminates the risk of leakage even when the conductive paste is press-fitted.

In the fuel cell main body 10 configured as described above, the single cell S is sealed by fitting the recess 31a formed in the frame member 14 with the protrusion 31b formed on the cell adjacent to the single cell S. A portion 32 is formed to maintain gas sealing properties. In the fuel cell main body IO in which a plurality of single cells S are stacked, hydrogen gas (H7) is supplied to manifolds 19.20 for hydrogen gas flow paths that communicate with each other as shown by arrow A, and passes through channels 21.22 to the anode. It is supplied to the plate 11. Further, the supplied hydrogen gas reacts with oxygen through the solid electrolyte body 13, and water, which is a reactant, is discharged to the outside through the hydrogen gas flow path 41. Air is supplied to the air flow manifolds 25° 26 which communicate with each other as shown by arrow B, and through the channels 27, 28.
It is supplied to the anode plate 12 through. The reaction formation formula and anode reaction in this case are L(t+ 2 e −→HzO+ 2 e
− is.

Soft conductive materials such as conductive paste, aluminum die-casting, and low-temperature brazing materials are connected to the cathode-side busbar manifold 2, which communicate with each other as shown by arrows C in FIGS. 1 and 4.
9 and joined to the cathode side current collector 15 of each cell. Similarly, the soft conductive wires are press-fitted into the anode-side busbar manifolds 30 that communicate with each other as shown by the arrows, and are joined to the anode-side current collectors 16 of each cell, and connected to the connection terminals 44a and 44b, respectively. be done.

A monoyl battery stacked in such a configuration has a configuration in which single cells are electrically connected in parallel. A predetermined voltage can be generated by electrically connecting such modules in series.

The fuel cell according to the first embodiment of the present invention as described above has the following advantages.

(a) In a fuel cell in which multiple single cells are stacked in series, not only the gas supply manifold but also a busbar for taking out the electrical energy collected by the current collector is installed inside the cell frame, so the whole fuel cell can be made compact.

(b) Since the frame plate is made of oxide-based ceramics such as alumina material, it is possible to obtain a frame material that satisfies heat cycle resistance, insulation resistance, and oxidation-reduction resistance.

(c) When the single cells are stacked together, the four parts of the frame (E) and the convex parts on the adjacent cells fit together, resulting in improved gas flow properties.

(d) Busbar is conductive paste 1 alumina die-casting,
Since it is formed by press-fitting low-temperature brazing material or the like, it can be installed inside the cell frame.

(e) Since the bus bar is formed within the single cell, assembly work when stacking a plurality of single cells can be done easily.

In the above example, the frame member! The material of step 4 is alumina (All!
203), the material of the busbars 37 and 38 is conductive paste, and the seal portion 32 is a convex-concave fitting.
In the present invention, various other modifications can be considered using various combinations of these materials or the seal portion 32 as described below.

That is, as shown in FIG. 5(B), the seal portion 32 is
A concave portion 31a or a convex portion 31b is formed in the frame plates 14a and 14b of the frame member 14, and these four portions 3Ia and convex portions 31b are fitted in a green sort 31c state, that is, a firing curved state, and then fired to form a knoll portion. 32 and maintains gas sealing properties. Therefore, since the single cells are stacked together by fitting the concave part of the frame member in the green sheet state 31 (?) with the convex part on the adjacent single cell and then firing, a precise sealing property without gas leakage can be obtained.

As shown in FIG. 5(C), the frame plates 14a and 1 of the frame member 14 are
4b are formed with opposing recesses, and the frame plates 142L and 14
A copper gasket 31d is placed in the groove formed by overlapping b.
The seal portion 32 is formed by inserting the . Therefore, since the stacking of single cells seals the recess 31a of the frame member and the recess 31a on the adjacent cell through the copper packing 31cl, gas sealing performance is improved.

Further, as shown in FIG. 5(D), the glass cement 31e as a bonding material is applied in the form of a slimy liquid or is printed on a screen, and the bonding is performed by raising the temperature to a temperature at which the glass cement 31e solidifies. do.

In this case, the temperature can be obtained by raising the temperature to 600°C at a heating rate of 100°C/h (hour), maintaining this temperature for 1 hour, and then lowering the temperature to room temperature at a rate of 50°C/h. Further, the knoll portion 32 is connected to the frame plate 14a.
, 14b, a concave portion may be formed on one side, and a convex portion may be formed on the other side, and these may be fitted and bonded with glass cement. In this way, glass cement is coated or screen printed on the joining surfaces of the frame plates, and the glass cement is used as a joining material, so that gas sealing properties are improved.

Further, the frame member 14 is made of zirconia material, the bus bars 37 and 38 are made of conductive paste, and the seal portion 32 is made of a conductive paste.
The concave portion 31a and the convex portion 31b are fitted and laminated in a green sheet state, that is, in a state before firing, and then fired.

Further, as shown in FIG. 5(C), a seal portion 32 is formed in a recess 31a in a frame plate 14a of a frame member 14 and a frame plate 1.
4b and a copper gasket 31d.

Furthermore, as shown in FIG. 5(D), the knoll portion 32
Glass cement 31e is applied to the joint surface of frame plates 14a and 14b.
The seal portion 32 is formed by coating or screen printing and bonding using glass cement as a bonding material.

H. Effects of the Invention The present invention is as described above, and a through hole for an anode side bus bar and a through hole for a cathode bus bar are formed in the frame part (O), and an anode plate is formed in the through hole for an anode side bus bar. In addition to inserting a bus bar that connects to the cathode plate, we also inserted a bus bar that connects to the cathode plate into the through hole for the cathode side bus bar, so the bus bar does not take up space outside the laminate, making the overall structure compact. Furthermore, when stacking a plurality of single cells, there is no need for complicated connection work between the current collector and the bus bar, and a fuel cell that is easy to manufacture and can be miniaturized can be obtained.

Further, according to the present invention, the frame member of the single cell is formed by laminating unfired alumina and then firing to form the frame member, the bus bar is made of a soft conductive material, and the sealing part is formed by using a green sheet with uneven fitting. Since the fired copper packing and crow cement are used, a highly reliable stacked fuel cell that fully satisfies various requirements for fuel cells can be obtained.

[Brief explanation of the drawing]

FIG. 1 shows a stacked fuel cell according to an embodiment of the present invention, and is a sectional view taken along line I-1 in FIG. 3, and FIG.
3 is a plan view of a fuel cell according to an embodiment of the present invention, FIG. 4 is a perspective view of a single cell group, and FIGS.
D) is an enlarged view showing a modified example of the seal portion, and FIG. 6 is a diagram showing the basic structure of the fuel cell. DESCRIPTION OF SYMBOLS 11... Negative electrode, 12... Positive electrode, 13... Electrolyte object, +4 .=Frame member, l4a-l4c-
Frame plate, 15° 16...Current plate, 19.20...Manifold for hydrogen gas flow path, 25.26...Through hole for air flow path, 29.30...For bus bar Through hole, 31
a...Convex portion, 31b/Concave portion, 31c=Green notebook, 31d Copper packing, 31e...Glass cement,
37...Busbar on cathode side 38...Busbar on anode side 40.41...Busbar insertion hole, 42.43.
...Gas flow path. FIG. 1 Fuel cell according to the embodiment FIG. 3 Plan view +1 - cathode 12 - cathode 3 Electrolyte body 14 Frame members 43 to +4b Frame plate 5.16, current collector plate 19.20, hydrogen gas through hole 25 .26 - Air passage through hole 29.30...Busbar penetration hole 31a - Convex part 31b - Concave part 32- Knoll part 37 - Cathode busbar 38 - Anode busbar 5a, 45b - Fuel manifold Fig. 5 (A ) (B) (C) (D) Figure 6 Principle diagram of stacked fuel cell

Claims (1)

[Claims] (1) A single cell is constructed by incorporating an electrolyte object and anode and cathode electrode plates located on both sides of the electrolyte object into a frame member, and a plurality of these single cells are connected to each other between the anode electrode plates and the cathode electrode plates. In a fuel cell stacked so as to face each other and to form fuel manifolds between electrode plates of the same polarity, the frame member is formed by laminating unfired alumina and then firing it. A through hole for an anode bus bar and a through hole for a cathode bus bar are formed in the frame member, and an anode bus bar formed from a soft conductive material is formed in the through hole for the anode bus bar so as to be connected to the anode plate. At the same time, a cathode busbar formed from a soft conductive material is provided in the through hole for the cathode busbar so as to be connected to the cathode plate, and a seal portion is interposed between adjacent frame members of the single cell. A stacked fuel cell characterized by being configured as follows.