JPH0246661A - Stacked fuel cell - Google Patents

Abstract

PURPOSE:To make manufacture easy and to make a fuel cell compact by inserting a cathode bus bar made of low temperature solder for connecting cathode plates into a through for the cathode bus bar, and inserting an anode bus bar made of low temperature solder for connecting anode plates into a through hole for the anode bus bar. CONSTITUTION:A through hole for a cathode bus bar 38 and a through hole for an anode bus bar 37 are installed in frames 14 made of heat resistant insulator. A bus bar 38 made of low temperature solder is inserted into the through hole for the cathode bus bar 38 to connect cathode plates 12. An anode bus bar 37 made of low temperature solder is inserted into the through hole for the anode bus bar 37 to connect anode plates 11. A sealing member 32 is arranged between adjacent frames 14 of unit cells. Electric energy is taken out through the bus bars 37, 38. Gas sealing capability is ensured with the sealing member 32. Manufacture of a fuel cell is made easy and its size is made compact.

Description

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

B. Summary of the Invention 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, and a plurality of single cells are arranged so that the electrode plates of the same polarity face each other and ,
In a structure in which electrode plates of the same polarity are stacked to form fuel manifolds, 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 and the anode electrode, and the cathode conductor and the cathode electrode, respectively, and providing a sealing portion between adjacent frame members, a fuel cell that is easy to manufacture, miniaturized, and excellent in safety is obtained.

C1 Prior Art A fuel cell main body is constructed by arranging anode and cathode electrode plates on both sides of a solid electrolyte to constitute a unit cell (single cell), and a plurality 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.
Hydrogen gas H is supplied to the cathode plate side of each unit cell S of a plurality of unit batteries (single cells S), a restraining plate 1aIb that stacks and fixes these unit cells S in series, and the stacked and fixed battery body lO. It consists of a hydrogen gas supply manifold 2, an air supply manifold 3 that supplies air to the anode plate side, and current collection leads 4 and 5 that extract electricity from the anode plate and cathode plate of each single 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.

D1 Problems to be solved by the invention In the conventional stacked fuel cell, the first problem is as follows.
Because 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 required to stack multiple single cells was complicated.

However, it has been proposed in Japanese Patent Application Laid-Open No. 17781/1981 to provide a gas supply manifold inside the cell frame and thereby reduce the overall structure of the cell. However, installing a busbar inside the cell frame for extracting the electrical energy collected by the current collector to the outside has not been done until now because the connection between the current collector and the busbar becomes 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. must be paid.

The present invention has been made in view of the above-mentioned conventional problems, and its purpose is to provide a through hole for a bus bar inside the frame of a single cell in a stacked fuel cell, and after stacking the single cells, each cell To provide a stacked fuel cell that can be manufactured easily and miniaturized by inserting a bus bar that connects to a current collector and forming an effective seal between frame members of adjacent cells. That's true.

86 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 constitute a single cell. In a fuel cell in which a plurality of single cells are stacked in series, the frame member of the single cell is made of a heat-resistant insulator, and a through hole for an anode bus bar and a through hole for a cathode bus bar are formed in the frame member, A low-temperature brazing material busbar is inserted into the through-hole for the surface anode busbar so as to connect with the anode plate, and a low-temperature brazing material busbar is inserted into the through-hole for the cathode busbar to connect with the cathode plate. A stacked fuel cell is constructed by inserting a cathode bus bar and interposing a seal portion between adjacent frame members of the single cells.

When the anode busbar is inserted into the anode busbar through-hole formed in the F1 action frame member, the anode busbar is connected to the anode plate, and the cathode busbar is also inserted into the cathode busbar through-hole formed in the frame member. When installed, the cathode bus bar is connected to the cathode plate. Therefore, electrical energy is taken out through each busbar provided within the frame. 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 4.

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. 5 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.

[First Example] In FIGS. 1 to 5, 11 is a cathode plate (made of platinum, etc.).
electrode plate),! 2 is an anode plate (electrode plate) also made of platinum or the like, and 13 is a solid electrolyte object made of, for example, stabilized zirconia in which an oxide such as yttrium calcium is dissolved in zirconia, lanthanum fluoride, or the like. These cathode plates 11. Anode plate 12. The solid electrolyte object 13 is a frame member 14
A single cell S is configured by being incorporated into the inside. 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 13. Cathode side current collector 15. As shown in FIG. 4, manifolds 19 and 20 for hydrogen gas flow paths are provided at mutually opposing corners 17 and 18 of the frame member 14 incorporating the anode side current collector 16, and groove-shaped grooves are provided in each of the manifolds 19 and 20 for hydrogen gas flow paths. Channels 21 and 22 are provided, and the cathode plate! ■ and manifolds 19 and 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 weight 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 includes a frame plate 14a having a hollow disc shape and an annular protrusion;
14b and a hollow frame plate 14c are stacked together with a glass seal 43 interposed therebetween.A negative electrode plate 11 and a current collector plate 15 are arranged between the frame plates 14a and 14c, and the frame plates 14b and 14c are stacked together.
A positive electrode plate 12 and a current collector plate 16 are disposed between the electrode plates 11 and 12, and a solid electrolyte body 13 is interposed between the electrode plates 11 and 12 to form 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 manifold 45a for hydrogen gas is formed between the cells on the negative electrode plate 11 side, and a manifold 45b for air is formed on the side of the positive electrode plate 12. A through hole 39 and a through hole 40 for an anode bus bar are formed, and conductive paste is press-fitted into these through holes 39 and 40 to form a cathode bus bar 37 and an anode bus bar 38.

Low-temperature brazing materials (e.g. phosphorous brazing).

When press-fitting brass solder etc.) into the busbar through-hole 39.40 to form the busbar 37.38, a low-temperature brazing material is press-fitted. Furthermore, the single cells must be sealed to prevent the low-temperature brazing material from leaking to areas other than the busbar through holes 39 and 40 during press-fitting.

Alumina (AI) is a frame material that satisfies these performances.
2tOs), zirconia, mullite, magnesia, or other oxide-based ceramics. In addition, a recess 31 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, a hydrogen gas flow path 41 and an air (0,) flow path 42 are formed as shown in FIG.
is formed. The hydrogen gas flow path 41 communicates with the channel 21, and the air flow path 42 communicates with the 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 IO configured as described above, the single cell S is sealed by fitting the four parts 31a formed on the frame member 14 and the convex part 31b formed on the cell adjacent to this 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 (H2) is supplied to hydrogen gas flow path manifolds 19.20 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 If. 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 Hz+ 2 e −→H*0 + 2 e
− is.

The low-temperature brazing materials are connected to the cathode-side busbar manifold 29, which communicate with each other as shown by arrows C in FIGS. 1 and 4.
It is press-fitted into the cell and joined to the cathode side current collector 15 of each cell.

Similarly, the low-temperature brazing material is press-fitted into the anode-side busbar manifolds 30 that communicate with each other as shown by the arrows, and is joined to the anode-side current collector 16 of each cell, and connected to the connection terminals 44a and 44b, respectively. Ru.

A module battery stacked in such a configuration has a configuration in which unit 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, zirconia, and mullite-magnesia, 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 concave portion of the frame material and the convex portion on the adjacent cell fit together, resulting in improved gas sealing properties.

(d) Since the bus bar is formed by press-fitting low-temperature brazing material, 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 first embodiment, the material of the frame member 14 is alumina CAQ.
t03), the material of the busbars 37 and 38 is a low-temperature brazing material, and the seal portion 32 has a concave-convex fit, but in the present invention, these materials or the seal portion 32 may be made of various materials as described below. Various other combinations can be considered.

[Second Embodiment] In the second embodiment, the seal portion 32 in the first embodiment described above is replaced with a concave portion 31a or a convex portion in the frame plates 14a and 14b of the frame member 14, as shown in FIG. 5(B). The concave portion 31a and the convex portion 31b are fitted together in the state of the green sheet 31c, that is, in the state before firing, and then fired to form the seal portion 32 and maintain gas sealing properties. Therefore, since the single cells are stacked together by fitting the concave portion of the frame member in the green sheet state 31c with the convex portion on the adjacent single cell and then firing, a precise sealing property without gas leakage can be obtained.

[Third Embodiment] In the third embodiment, in the first embodiment described above, the frame plate 14a of the frame member 14 is changed as shown in FIG. 5(C).
and 14b are formed with opposing recesses, respectively, and frame plates 14a and 14b are formed with opposing recesses.
Copper gasket 3 is placed in the groove formed by overlapping 4°b.
1d is inserted to form the seal portion 32. Therefore, in the third embodiment, since the stacking of single cells is performed by sealing the recess 31a of the frame member and the recess 31a on the adjacent cell through the copper packing 31d, the gas sealing property is improved. will improve.

[Fourth Embodiment] In the fourth embodiment, as shown in FIG. 5(D), the seal portion 32 of the first embodiment is coated with glass cement 31e as a bonding material in the form of a slime, or It is constructed by screen printing and bonding by raising the temperature to a temperature at which the glass cement 31e solidifies.

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 seal portion 32 includes the frame plate 14a,
A concave portion and a convex portion may be formed on one side of 14b, and these may be fitted and bonded with glass cement. As described above, in the fourth embodiment, glass cement is applied or screen printed on the joint surfaces of the frame plates, and the glass cement is used as the jointing material, so that the gas sealing property is improved.

[Fifth Embodiment] In the fifth embodiment, the frame member 14 is made of zirconia, the bus bars 37 and 38 are made of low-temperature brazing material, and the seal portion 32 is formed by fitting the four portions 31a and the convex portions 31b. In this fifth embodiment, since the material of the frame member 14 is zirconia, it is possible to obtain a frame member that satisfies heat cycle resistance, insulation resistance, and oxidation-reduction resistance.

[Sixth Example] In the sixth example, the material of the frame member 14 is zirconia material, the material of the bus bars 37 and 38 is low temperature brazing material,
The seal portion 32 is laminated by fitting the concave portion 31a and the convex portion 31b in a green sheet state, that is, in a state before firing,
It is then fired.

[Seventh Example] In the seventh example, the material of the frame member 14 is zirconia (
ZrOt), the material of the bus bars 37 and 38 is low-temperature brazing material, and the seal portion 32 is the frame plate 14a of the frame member 14.
A recess 31a formed in the frame plate 14b and a recess 31 formed in the frame plate 14b.
a and a copper gasket 31d.

[Eighth Embodiment] In the eighth embodiment, the frame member 14 is made of zirconia (ZrOt), and the bus bar 37. The material of $8 is a low-temperature brazing material, and the sealing portion 32 is constructed by coating or screen printing glass cement on the joining surfaces of the frame plates 14a and 14b, and joining them using glass cement as a joining material.

H1 Effects of the Invention The present invention is as described above, in which a through hole for an anode bus bar and a through hole for a cathode bus bar are formed in a frame member, and the through hole for an anode bus bar is connected to an anode plate. In addition to inserting a bus bar made of low-temperature brazed material, we also inserted a bus bar made of low-temperature brazed material to be bonded to the cathode plate into the through hole for the cathode side bus bar, so that the bus bar does not take up space on the outside of the laminate. This makes the whole structure more 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.

Furthermore, according to the present invention, the material of the frame member of the single cell is alumina or zirconium, the material of the bus bar is low-temperature brazing material, and the seal part is made of uneven fitting, green sheet firing, copper packing, and crow cement. It is possible to obtain a highly reliable stacked fuel cell that fully satisfies various requirements for batteries.

[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. 11... Negative electrode, 12... Positive electrode, 13... Electrolyte object, l 4... Frame member, 14a-14cm frame plate, 15° 16... Current collector plate, 19.20...・Manifold for hydrogen gas flow path, 25.26... Through hole for air flow path, 29.30... Through hole for bus bar, 31a・
...Convex portion, 31b...Concave portion, 31c...Green sheet, 31d...Copper packing, 31e...Glass cement, 37...Cathode side bus bar made of low temperature brazing material 38...Low temperature Busbar on the anode side made of brazing material 40° 41...Busbar insertion hole, 42.43...
・Gas flow passage. 11 ・Cathode electrode 12・・Positive electrode 13・・Electrolyte object 14 Frame material 1411A+l 4 c・Frame plate 15.16 Collection ii board 19.20 ・Through hole for hydrogen gas 25.26・・Through hole for air passage 29 .30... Bus bar through hole 31a... Convex part 31b... Concave part 32... Nuru part 37 - Cathode bus bar 38 - Anode bus bar 45a, 45b Fuel manifold Figure 3 + Concave surface (A) (C) No. Figure 5 (B) (D) Figure 6

Claims (6)

[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 such that the electrode plates of the same electrode face each other and form fuel manifolds between the same electrode plates, a through hole for an anode bus bar and a through hole for a cathode bus bar are formed in the frame member. An anode bus bar made of a low temperature brazing material is provided in the through hole for the anode bus bar so as to be connected to the anode plate, and an anode bus bar made of low temperature brazing material is provided in the through hole for the cathode bus bar so as to connect to the cathode plate. 1. A stacked fuel cell characterized in that a cathode bus bar made of brazing material is provided, and a seal portion is interposed between adjacent frame members of the single cell. (2) The stacked fuel cell according to claim 1, wherein the heat-resistant insulator is an oxidizing ceramic material. (3) The laminated layer according to claim 1 or 2, wherein the seal portion is formed by fitting recesses and projections formed on mutually adjacent frame members of the plurality of unit cells. type fuel cell. (4) A claim characterized in that the seal portion is formed by fitting concave portions and convex portions formed in mutually adjacent frame members of the plurality of unit cells before firing the frame members, and then firing the same. Stacked fuel cell according to item 1 or 2. (5) The sealing portion is constructed by inserting a copper packing between recesses formed in the frame members adjacent to each other of the plurality of unit cells.
Stacked fuel cell. (6) The stacked fuel cell according to claim 1 or 2, wherein the seal portion is formed of glass cement inserted between adjacent frame members of the plurality of unit cells.