JPH04306570A - Fuel cell - Google Patents

Abstract

PURPOSE:To provide a structure suitable for supplying electrolyte as well as to provide a structure suitable for removing cells whose performances are worsened. CONSTITUTION:A fuel cell is constituted of plural number of layered cell units provided with an anode separator 1, an electrolyte preserving layer 3 and an cathode separator 2, and at least two or more anodes or cathodes of the separators in the respective cell units are connected mutually in parallel so as to form a short circuit, and one of the electrolyte preserving layers 3 mentioned above is made to serve also as an insulating member against electronic conductivity between the respective cell units.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention is applicable to fuel cells.
The present invention relates to a laminated structure of a separator, a method for replenishing electrolyte inside a battery or adjusting the amount of the electrolyte, and a method for separating a unit cell whose performance has deteriorated from the whole.

0002

[Prior Art] Conventionally, replenishing or storing electrolyte in a fuel cell involves: 1) creating a space to store the electrolyte inside the battery;
Using a method of transferring the electrolyte from the spot to the electrode or electrolyte plate, ■ Pouring the electrolyte from the side of the cell, ■
A method has been proposed in which a hole is formed through the laminated cell and an electrolytic solution is allowed to flow in from the outside through the hole. JP-A-1-
89150 and JP-A-1-29308, excessive electrolyte is stored in holes or other spaces provided inside the cell, and as the amount of electrolyte decreases during battery operation, the electrolyte may seep into the battery. It has a similar structure. Tokukai Showa 6
Publication No. 2-154573 provides a structure in which a pipe for replenishing electrolyte is connected in the lateral direction of an electrolyte layer in a single cell, and the liquid is poured into the cell. JP-A-63-241868 and JP-A-1-307172 provide a structure in which a through hole is opened in the stacking direction in a stacked cell, and an electrolytic solution is poured into the hole from the outside. Japanese Patent Publication No. 2-27
No. 670 provides a fuel cell in which single cells are electrically connected to each other via a crossover lead.

0003

[Problems to be Solved by the Invention] The above-mentioned conventional technology does not take into account the amount of electrolyte to be impregnated into the battery or the elapsed operation time during which impregnation is required, and the problem is that the electrolyte impregnation process cannot be managed and controlled. There was a point. Further, in the above-mentioned conventional technology, it is not easy to create a replenishment pipe in the electrolyte layer of each cell, considering that the thickness of a single cell is thin and that a large number of cells are stacked in an actual battery. Moreover, the above-mentioned prior art does not take into consideration the possibility that each cell may be short-circuited by the electrolyte when the electrolyte is poured through the through hole. In conventional cells, when a liquid short circuit occurs between cells having different potentials, there is an unavoidable risk that the electrolyte migrates to one cell, resulting in deterioration of battery characteristics. Furthermore, in the conventional example described in JP-A-2-27670, each cell is stacked via an insulating frame, which has the disadvantage that the number of parts increases and it is difficult to reduce the stacking height. was.

One of the objects of the present invention is to suppress the influence of electrolyte movement due to a liquid short circuit between cells, and to suppress the influence of electrolyte movement caused by a liquid short circuit between cells by making the electrolyte holding layer between laminated separators have a structure that allows liquid short circuit. The purpose is to make it possible to manage the amount of electrolyte in the cell throughout the laminated block. Furthermore, it is possible to easily replenish or remove the electrolytic solution in order to manage the amount of the electrolytic solution.

Another object of the present invention is to propose a new structure different from conventional cells, to increase the output density per cell area, to develop a method for removing specific cells from the whole, and to simplify the cell structure. There is a purpose to Specifically, the separator of one large area cell is divided into smaller separators of the same shape, and the separators of the same polarity are short-circuited in parallel to create a stacked structure, which produces the same amount of output as the large area cell. The idea is to achieve this with a fraction of the cell area.

Another object of the present invention is to divide the separator of one large-area cell into small separators of the same shape and create a laminated type in which the separators of the same polarity are short-circuited in parallel. The purpose is to release the unit cell from a short-circuited state and to enable it to be separated from the whole.

Another object of the present invention is to provide an electrolytic tank type fuel cell structure which is simple in structure by immersing an anode separator and a cathode separator in a free volume electrolyte reservoir. .

[0008]

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a structure in which an anode separator, an electrolyte holding layer, a cathode separator, an electrolyte holding layer, and an anode separator are laminated in this order. A plurality of cell units each having a layer and a cathode separator are stacked, and at least two or more anodes and/or cathodes of the separators in each cell unit are short-circuited in parallel, and the one The fuel cell is characterized in that the electrolyte holding layer also serves as an insulating member for electron conductivity between each cell unit.

[0009] In the above-mentioned fuel cell, it is preferable that the electrolyte holding layers between the separators short-circuited in parallel are short-circuited with each other by an electrolyte. Further, it is preferable that at least one gas diffusion type electrode is provided on a surface in contact with the electrolyte, such as a surface in contact with the electrolyte holding layer in the stacking direction or a surface short-circuited with the electrolyte. Further, it is preferable that an electrolytic solution amount adjusting mechanism is provided for adding or removing a certain amount of electrolytic solution to the electrolytic solution holding layer in liquid contact. Further, it is preferable that a reflux mechanism is provided in which a certain amount of the electrolyte is refluxed within the electrolyte holding layer which is connected to the liquid. Further, it is preferable that the terminals that short-circuit the separators in parallel can be removed or rearranged, and any separators can be separated from the whole. Further, it is preferable that a separator group in which the same poles are short-circuited in parallel is used as one block, and a plurality of the blocks are stacked in series to increase the capacity.

The present invention also provides a method of immersing at least one or more anode separators and cathode separators arranged with a constant gap in one molten electrolyte reservoir, and at least two or more anodes of the separators Alternatively, it is an electrolytic cell layer type fuel cell having a structure in which cathodes are short-circuited in parallel. Here, it is preferable that the terminals that short-circuit the separators in parallel can be removed or rearranged, and that any separator can be separated from the whole. It is preferable that a group of parallel short-circuited separators in one electrolytic solution reservoir be used as one block, and a plurality of the blocks may be connected in series to increase the capacity. Also, it is preferable to have terminals connected in series across a plurality of electrolyte reservoirs.

[0011]

[Operation] The structure in which the electrolyte layer of each cell can be connected to each other by penetrating the laminated separator eliminates any current leakage due to liquid short circuit, which is a problem in conventional laminated batteries. Furthermore, by providing liquid junctions for all cells, the electrolyte can be added or removed while taking into account the overall balance of the battery, so the amount of electrolyte in the battery can be maintained at an optimum level. This allows the battery to maintain high performance and extend its life.

[0012] By dividing one large-area separator into small separators of the same shape that are a fraction of the size, and creating a laminated structure in which separators of the same polarity are short-circuited in parallel, a series laminated structure can be created. This enables a fuel cell structure in which separators of the same polarity are connected in parallel. this is,
This has the great advantage of being able to construct a large capacity battery while reducing the area occupied by the cell compared to the conventional one.

Furthermore, since the separators of the same polarity are connected in parallel, any cell can be separated from the whole by simply opening the connected terminals. As a result, even if some of the cells have defective characteristics, the overall battery characteristics will not be impaired or the lifespan will be limited.

[0014]

EXAMPLES Example 1 FIG. 1 shows an example of the present invention. A plurality of blocks each having a pair of anode separator 1 and cathode separator 2 sandwiching an electrolyte holding layer 3 as a unit cell are stacked with the electrolyte holding layer 3 of another cell interposed therebetween. Here, each separator 1, 2 is made of SUS310, and the electrolyte layer 3 is L
A porous plate made of iAlO2 as a base material is impregnated with molten carbonate. In the laminated body, the separators having the same polarity are short-circuited by parallel terminals 8 and 9. The figure is a longitudinal cross-sectional view of a stacked battery, and the manifold that supplies reactive gas to each electrode is omitted. In the figure, 4
5 represents an anode gas supply furnace, and 5 represents a cathode gas supply furnace. It is assumed that the oxidizing gas and the reducing gas are supplied through a common manifold to the anode 6 and cathode 7, respectively. Here, the anode 6 is a Ni-based polygonal plate, and the cathode 7 is
is composed of a NiO-based multilayer plate. The terminals connected to each separator of the laminated cell have terminals 11 for short circuiting, and any separator can be separated.

According to this embodiment, it has become possible to connect stacked batteries in parallel, which was not used in the conventional concept. For example, if the battery characteristics per unit cell are a ampere (A) and b volts (V), the current value that can be taken out by n stacks is a×n (A) and the cell voltage is b (V). Therefore,
The output is (a×n)×b=n・a・b(W). On the other hand, in a conventional cell with a series stacked structure in which the separators of unit cells are not insulated, the current value a (A) and the cell voltage b
×n(V) and output a×(b×n)=na·a·b(W). Therefore, parallel connection does not impair battery output. Here, in the illustrated battery, the current flowing through one terminal is a(A). On the other hand, if a specific cell is short-circuited and removed in a conventional series stacked cell, a short-circuit terminal is required to flow the battery's pre-current n・a (A) due to the series connection, so the terminal There is a concern that it will become larger. Therefore, it can be said that this structure has a great effect in that cells whose characteristics have deteriorated can be easily removed by cutting off the short-circuiting terminal 11.

In addition, a problem with conventional cells is that the electrolyte leaks from the electrolyte layer, causing short circuits with adjacent unit cell blocks and impairing battery characteristics, but with this method, Even if there is a liquid short circuit between cells, the battery characteristics will not be impaired at all.

Further, the above embodiment has a structure in which gas diffusion type electrodes are arranged on both the upper and lower sides of one separator, and unit cell blocks are stacked with the electrolyte layer 3 sandwiched therebetween. Therefore, according to this embodiment, it is possible to extract twice as much current through the insulating plate as compared to the conventional laminated structure. Further, this embodiment has a great effect in simplifying the battery stack structure and improving the volumetric output density of the battery.

Embodiment 2 A second embodiment of the present invention is shown in FIG. This embodiment has a structure in which the electrolytic solution layer junction 12 is provided in the longitudinal direction of the separators 1 and 2 of the laminated cell in the above-mentioned embodiment 1, and the electrolytic solution holding layer 3 of each unit cell is short-circuited. According to this embodiment, the amount of electrolyte in each unit cell is balanced, and the amount of electrolyte in each electrolyte holding layer 3 can always be kept at a constant level during battery operation. For example, even if a certain unit cell block runs out of electrolyte, it is more effective at replenishing the electrolyte than other cell blocks, maintaining high battery characteristics over a long period of time, and improving battery life. . Furthermore, the electrolyte layer liquid junction 12 is connected to a circulation pump 21 for refluxing the electrolyte.

Embodiment 3 A third embodiment of the present invention is shown in FIG. This embodiment has a structure in which electrolyte layer junction ports 12 are provided in the longitudinal direction of the separators 1 and 2 of the laminated cell, and the electrolyte holding layer 3 of each unit cell is short-circuited, similar to the above-mentioned embodiment 2. In addition, the liquid junction 21 filled with electrolyte is connected to the electrolyte supply tank 1 outside the battery.
It communicates with 3. When the characteristics of the battery deteriorate during battery operation or when the resistance of the electrolyte layer increases, the electrolyte is replenished from the electrolyte replenishment tank 13 and distributed throughout the battery. This has the effect of restoring battery characteristics and reducing the resistance of the electrolyte layer.

In this embodiment, a liquid junction for the electrolytic solution is established through a hole penetrating the battery, but the structure can be further simplified if the liquid junction is shared within the gas supply manifold. A liquid junction structure outside the battery, such as a porous wick attached to the side wall of the battery, is also considered. In any case, any structure may be used as long as a liquid junction is provided between each unit cell.

Embodiment 4 A fourth embodiment of the present invention is shown in FIG. This embodiment has a structure in which the parallel-connected stacked cells (hereinafter referred to as parallel cells) of the first embodiment are stacked in series. In this embodiment, parallel cells 16, 1
This is an example in which three pieces of 7 and 18 are stacked. The individual parallel cells are stacked without providing an insulating layer between them. For serial stacking, each parallel cell has a separator 14 at the upper end.
is the anode, and the separator 15 at the lower end is the cathode, and the entire load is applied to the upper and lower separators 14, 1.
Take it out from 5.

In this embodiment, the capacity is increased by stacking parallel cells 16, 17, and 18. In this way, there is no need to provide special terminals or the like in the stacking of each parallel cell, and stacking can be easily performed in the same way as a conventional stacked battery. In addition, with such a stacked structure of parallel cells, maintenance such as replacement can be performed using the parallel cells as one unit.

Embodiment 5 A fifth embodiment of the present invention is shown in FIG. This embodiment has a structure in which a porous insulating plate 19 is arranged between each unit cell to prevent a short circuit in the parallel cell of the first embodiment, and the entire parallel cell is immersed in an electrolyte reservoir 20. The porous insulating plate 19 sufficiently absorbs the electrolyte in the liquid reservoir 20, and the
It performs the same function as the electrolyte layer. However, there is a concern that the electrolyte may excessively permeate into the electrode, so for gas-diffusive electrodes, a certain pressure is applied to the reactant gas to prevent the electrolyte from penetrating beyond a certain amount. It is better to prevent it. This example has the effect of replenishing the electrolyte to the entire battery as in Example 4, so it is possible to prevent the characteristics of the battery from deteriorating and the resistance of the electrolyte layer from increasing during battery operation.

[0024]

According to the present invention, a battery having the same capacity as a separator with a large area can be constructed using a separator with a fraction of the area of the separator, which has the effect of increasing the output density per cell area.

Furthermore, since the present invention has a structure in which the electrolyte holding layer between the laminated separators can be short-circuited, it is possible to suppress the influence of current leakage due to a liquid short-circuit between cells.
This is effective in making it possible to manage the amount of electrolyte in the laminated cells throughout the laminated block. Furthermore, in order to manage the amount of electrolyte, we added a mechanism to easily replenish or remove the electrolyte, so if the battery characteristics deteriorate during battery operation or if the resistance of the electrolyte layer increases. When it rises, it has the effect of restoring battery characteristics and reducing the resistance of the electrolyte layer.

Furthermore, the present invention has the effect of simplifying the overall structure of the battery by immersing the anode separator and cathode separator in a free volume electrolyte reservoir.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

FIG. 2 is a sectional view showing another embodiment of the present invention.

FIG. 3 is a sectional view showing another embodiment of the present invention.

FIG. 4 is a sectional view showing another embodiment of the present invention.

FIG. 5 is a sectional view showing another embodiment of the present invention.

[Explanation of symbols]

1 Anode separator 2 Cathode separator 3 Electrolyte holding layer 4 Anode gas supply path 5 Cathode gas supply path 6 Anode 7 Cathode 8 Anode parallel terminal 9 Cathode parallel terminal 11 Short circuit terminal 12 Electrolyte layer liquid junction 13 Electrolyte replenishment tank 14 Anode separator end plate 15 Cathode separator end plate 16 Parallel cell first block 17 Parallel cell second block 18 Parallel cell 3rd block 19 Porous insulation board 20 Electrolyte reservoir

Claims (11)

[Claims] Claim 1: An anode separator, an electrolyte holding layer,
A cathode separator, an electrolyte holding layer, and an anode separator are stacked in this order, and a plurality of cell units each having an anode separator, an electrolyte holding layer, and a cathode separator are stacked, and at least one of the separators in each cell unit is stacked. A fuel cell characterized in that two or more anodes and/or cathodes are short-circuited in parallel, and the one electrolyte holding layer also serves as an insulating member for electron conductivity between each cell unit. 2. The fuel cell according to claim 1, wherein the electrolyte holding layers between the separators short-circuited in parallel are short-circuited with each other by an electrolyte. [Claim 3] The fuel cell according to Claim 1 or 2,
A fuel cell characterized in that at least one gas diffusion type electrode is provided on a surface in contact with an electrolyte, such as a surface in contact with an electrolyte holding layer in a stacking direction or a surface that is short-circuited. 4. The fuel cell according to claim 2, further comprising an electrolyte amount adjustment mechanism for adding or removing a certain amount of electrolyte from the electrolyte holding layer connected to the liquid junction. 5. The fuel cell according to claim 2, further comprising a reflux mechanism for refluxing a certain amount of the electrolyte within the electrolyte holding layer which is in liquid junction. 6. The fuel cell according to claim 1, wherein the terminals for short-circuiting the separators in parallel can be removed or rearranged, and any separator can be separated from the whole. 7. The fuel cell according to claim 1, wherein one block is a group of separators in which the same poles are short-circuited in parallel, and a plurality of the blocks are stacked in series to increase the capacity. battery. 8. At least one or more anode separators and cathode separators arranged with a constant gap are immersed in one molten electrolyte reservoir, and at least two or more anodes or cathodes of the separators are separated from each other. An electrolyzer layer type fuel cell has a structure in which two cells are short-circuited in parallel. 9. The fuel cell according to claim 8, wherein the terminals that short-circuit the separators in parallel can be removed or rearranged, and any separator can be separated from the whole. [Claim 10] In the fuel cell according to claim 8 or 9, a group of separators short-circuited in parallel in one electrolyte reservoir is used as one block, and a plurality of the blocks are connected in series to increase the capacity. A fuel cell featuring: 11. The fuel cell according to claim 8, wherein terminals are connected in series across a plurality of electrolyte reservoirs.