JPH05242903A - Fuel cell stack body - Google Patents

Abstract

PURPOSE:To provide a highly practical fuel cell stack body capable of increasing output per unit fuel cell stack body, giving high cell characteristics and compactness, and substantially reducing cost per output by increasing the number of unit cell stacks for the number of cooling plates. CONSTITUTION:A unit cell stack body comprising a plurality of sub-stacks 19 is constituted of cooling plates 8 laid at both upper and lower ends, and inside of a plurality of cells 6. A plurality of the unit cells 6 are stacked between the cooling plates 8 laid at the upper and lower ends of the unit cell stack body, and a structural member including a current collector 9, an insulator 10 and a tightening plate 11 via separators 7, thereby forming an additional cell section 20. Or, the stack number of the unit cells 6 in the sub-stacks 19a at the upper and lower ends of the unit cell stack body is made larger than the stack number of other sub-stacks 19b in the center of the unit cell stack body.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel cell stack, and more particularly to a technique for improving the output per fuel cell stack by improving the stacking structure.

[0002]

2. Description of the Related Art Conventionally, a fuel cell has been known as a device for directly converting the chemical energy of fuel into electrical energy. In this fuel cell, usually, a pair of porous electrodes are arranged with a matrix holding an electrolyte in between, a fuel gas such as hydrogen is brought into contact with the back surface of one electrode, and oxygen or the like is put on the back surface of the other electrode. Unit cell that outputs electrical energy from between electrodes by using the electrochemical reaction that occurs when the oxidant gas of
A plurality of layers are laminated with a separator interposed therebetween.

In the fuel cell having such a structure, as long as the fuel gas and the oxidant gas are supplied to the back surfaces of the pair of electrodes, electric energy can be taken out with high conversion efficiency, and power generation efficiency can be achieved even with a small capacity. In particular, the demand for small-sized on-site fuel cell power generation plants is rapidly increasing in recent years. Further, the unit cell size can be expanded by the progress of the cell manufacturing technology, and the number of stacked fuel cell stacks tends to decrease.

FIG. 7 is a schematic perspective view showing a general structure of a unit cell constituting the above fuel cell. That is, as shown in FIG. 7, the anode electrode 2 and the cathode electrode 3 are arranged with the matrix 1 impregnated with the electrolyte sandwiched therebetween. In this case, the anode electrode 2 and the cathode electrode 3 are both formed of a porous material, and the front surface, which is the surface in contact with the matrix 1, is coated with the catalyst. In addition, the anode electrode 2 and the cathode electrode 3
A fuel gas flow passage 4 and an oxidant gas flow passage 5 are formed in a direction orthogonal to each other on the back surface located on the opposite side of the matrix 1. A unit cell 6 is formed by the matrix 1, the anode electrode 2, and the cathode electrode 3 as described above. In a phosphoric acid fuel cell, generally, the fuel gas is hydrogen and the oxidant gas is oxygen in the air.

Further, since the voltage obtained from one unit cell is generally as low as 1 V or less, as shown in FIG. 8, a large number of unit cells 6 are connected via a heat-resistant and phosphoric acid-resistant separator plate 7. It is configured to obtain a high voltage by forming the unit cell laminated body by stacking the unit cells. In this case, the number of stacked unit cells 6 forming one fuel cell is, for example, 400 to 500.

Incidentally, since the electrochemical reaction of the fuel cell as described above is an exothermic reaction, a large number of unit cells 6
When laminated, the total amount of heat generation becomes significant. Therefore, when stacking the unit cells 6, generally, as shown in FIG. 8, a cooling plate 8 is inserted for every fixed number of unit cells, and the heat generated by the electrochemical reaction is taken out to the outside. The temperature rise is prevented.

Further, the unit cell laminated body as described above has
Further, as shown in FIG. 9, a current collector plate 9, an insulating plate 10, a tightening plate 11, and a terminal 12 are attached to the upper and lower ends thereof, and are configured to be tightened from above and below by an appropriate tightening pressure. It Then, a pair of manifolds 14 to 17 for supplying and discharging the fuel gas and the oxidant gas are arranged to face each other on the side surface of the unit cell laminated body through the electrically insulating gasket 13. Then, the fuel cell stack is constructed by tightening and fixing with an appropriate pressure. Each manifold 14-17
A pipe 18 for supplying and discharging the fuel gas and the oxidant gas is connected to the. Further, the fuel cell stack having such a configuration is housed in a pressure vessel (not shown) and filled with an insulating seal gas such as nitrogen to complete a fuel cell.

FIG. 10 is a schematic side view showing an example of a conventional laminated structure in a fuel cell laminated body as shown in FIG. That is, the cooling plates 8 are arranged at the upper and lower ends of the plurality of stacked unit cells 6, and the cooling plates 8 are inserted into the inside thereof, so that between the two adjacent cooling plates 8,
A plurality of stacked unit cells 6 are sandwiched. The stacked unit cell 6 between the cooling plates 8 is usually formed by the sub-stack 1
9 but any sub-stack 1 in this example
Both 9 are also composed of 6 unit cells 6. Then, the current collector plate 9, the insulating plate 10, and the tightening plate 11 are respectively provided on the cooling plates 8 at the upper and lower ends of the unit cell stack formed by stacking the sub-stack 19 and the cooling plate 8 as described above. They are installed in sequence.

By the way, in the fuel cell stack having the above structure, the operating temperature range is extremely limited. That is, in a typical phosphoric acid fuel cell, the cell voltage is about 1 mV / cell
It is known from literature values and experimental results that the temperature rises by 0 ° C. Therefore, phosphoric acid fuel cells are generally operated at about 190 ° C. or higher. On the other hand, in the phosphoric acid fuel cell, when the operating temperature is about 230 ° C. or higher, the deterioration of the platinum catalyst, the loss of the phosphoric acid electrolyte, and the deterioration of the materials used are promoted, and the deterioration of the cell characteristics and the shortening of the life progress. Cause Therefore, the operating temperature range of the phosphoric acid fuel cell is generally set to about 190 to 220 ° C.

[0010]

However, in the conventional fuel cell stack, since the operating temperature range is extremely limited as described above, the number of unit cells stacked in the sub-stack is It is limited to a certain number due to the cooling capacity of the cooling plate, and as a result, the output per fuel cell stack cannot be increased, and the cell characteristics, compactness, and cost performance cannot be improved. have. This point will be described below.

First, in the fuel cell stack as shown in FIGS. 9 and 10, when the total number of unit cells is the same and the outputs are the same, the fuel is increased as the number of unit cells forming the sub-stack is increased. Reduce the number of cooling plates in the battery stack,
Battery characteristics and compactness can be improved, and cost can be reduced. That is, since the cooling plate becomes a factor of electric resistance and is thick and expensive, the smaller the number of cooling plates, the more advantageous the battery characteristics, compactness and cost.

However, since the cooling capacity of the cooling plate is limited, if the number of laminated unit cells forming the sub-stack is increased too much, the battery temperature may rise beyond the above-mentioned appropriate operating temperature range. There is a possibility of causing various problems as described above. Therefore, as described above, the number of stacked unit cells forming the sub-stack is
Due to the cooling capacity of the cooling plate, it is limited to a certain number. Therefore, in one fuel cell stack, the number of unit cell stacks with respect to the number of cooling plates is naturally limited. In this case, in the conventional example of the fuel cell stack shown in FIG. 10, the number of stacked sub-stacks is six. As described above, as a result of limiting the number of unit cell stacks with respect to the number of cooling plates, the conventional fuel cell stack cannot increase the output per fuel cell stack as described above, and Characteristics, compactness,
Also, it has a drawback that the cost performance cannot be improved.

In particular, at present, there is a great need to reduce the cost of fuel cells, and the output of a fuel cell stack having the same number of stacks is 1.
In order to increase the number by a factor of 5, solutions to many technically sophisticated and difficult problems are being investigated. If it is assumed that all of these problems have been solved and the costs of materials such as catalysts and manufacturing processes have not increased at all, the cost reduction effect is about 33%.

The present invention has been proposed in order to solve the problems of the prior art as described above, and an object thereof is to increase the number of unit cell stacks with respect to the number of cooling plates to provide a fuel cell stack. An object of the present invention is to provide a highly practical fuel cell stack capable of increasing the output per unit, having excellent cell characteristics and compactness, and significantly reducing the cost per output.

[0015]

In the fuel cell stack of the present invention, the temperature of the sub-stacks at the upper and lower ends of the conventional fuel cell stack is lower than the temperature of the sub-stack located at the center. It was proposed by paying attention to the point.

That is, FIG. 11 is a temperature distribution diagram of each unit cell when the conventional fuel cell stack shown in FIG. 10 is applied to a phosphoric acid fuel cell, and the fuel gas flow passage 4 of each unit cell is shown. The result of measuring the temperature by inserting a thermocouple (not shown) is shown in FIG. As shown in FIG. 11, the temperature of the sub-stacks arranged at the upper and lower ends is about 1
The temperature of the other sub-stacks arranged in the central part is about 200 to 220 ° C, while the temperature is 90 to 210 ° C. Therefore, the temperature of the upper and lower sub-stacks is about 10 ° C. lower than the temperature of the sub-stacks arranged in the central part. This phenomenon is a phenomenon caused by the heat of the sub-stacks at the upper and lower ends being absorbed by the structural material including the collector plate 9, the insulating plate 10, the tightening plate 11, and the like.
It is commonly found in conventional fuel cell stacks.
The temperature difference value is affected by the difference in heat transfer coefficient depending on the specifications of the structural material and the temperature difference of the insulating seal gas based on the design specifications of the operating conditions. If the specifications or the battery plant specifications change, the values will be different, but in any case, the temperature of the sub-stacks at the upper and lower end portions becomes lower than the temperature of the sub-stacks arranged at the central portion.

On the premise of the above phenomenon,
First, in the fuel cell stack according to claim 1, a plurality of unit cells are stacked via a separator between a cooling plate arranged at the upper and lower ends of the unit cell stack and the structural member, It is characterized in that an additional battery portion is formed. Next, in the fuel cell stack according to claim 2, the number of stacked unit cells of the sub-stack arranged at the upper and lower ends of the unit cell stack is
It is characterized in that the number of stacked unit cells is larger than the number of unit cells of the other sub-stacks in the central portion.

[0018]

The operation of the fuel cell stack of the present invention having the above construction is as follows. That is, in the fuel cell stack according to claim 1, the cell temperature of the additional battery portion formed between the cooling plates at the upper and lower ends and the structural material is the same as the cell temperature of each sub-stack sandwiched between the cooling plates. It is possible to adjust the number of stacked unit cells forming the additional battery unit so that the temperature level becomes appropriate. Therefore, it is possible to increase the number of unit cells stacked with respect to the number of cooling plates without causing problems such as deterioration of battery characteristics and shortening of battery life due to increase in battery temperature exceeding an appropriate operating temperature range. It is possible to increase the cell output per fuel cell stack.

Further, in the fuel cell stack according to the second aspect, the cell temperature of the upper and lower sub-stacks is adjusted so that the cell temperature of the sub-stacks of the upper and lower end portions becomes an appropriate temperature level similar to the cell temperature of the other central sub-stacks. It is possible to adjust the number of stacked unit cells forming the edge sub-stack. Therefore, like the fuel cell stack of claim 1, the number of unit cells stacked relative to the number of cooling plates can be increased without causing problems such as deterioration of cell characteristics and shortened battery life. The battery output per laminated body can be increased.

[0020]

EXAMPLES Some examples in which the fuel cell stack according to the present invention is applied to a phosphoric acid fuel cell will be described below with reference to FIG.
It will be described with reference to FIGS. In this case, FIG. 1 is a schematic side view showing a laminated structure in one embodiment (first embodiment) of the fuel cell laminated body according to the invention of claim 1, and FIG. 2 is each of the fuel cell laminated body of FIG. Unit cell temperature distribution diagram,
FIG. 3 is a temperature distribution diagram of each unit cell in a different embodiment (second embodiment) of the fuel cell stack according to the invention of claim 1, and FIG. 4 is an embodiment of the fuel cell stack according to the invention of claim 2. FIG. 5 is a schematic side view showing a laminated structure in an example (third embodiment), FIG. 5 is a temperature distribution diagram of each unit cell in the fuel cell laminated body of FIG. 4, and FIG. 6 is a fuel cell laminated body according to the invention of claim 2. It is a temperature distribution figure of each unit cell in an example (4th example) from which a body differs. The same parts as those of the conventional example shown in FIGS. 7 to 11 are designated by the same reference numerals and the description thereof will be omitted.

(1) Embodiment of the Invention of Claim 1 FIG. 1 is a diagram showing a first embodiment according to the invention of claim 1. In this first embodiment, each sub-stack 19 is composed of six unit cells 6, and two sheets are provided between the cooling plate 8 and the current collector plate 9 at the upper and lower ends of the unit cell stack. The additional cell unit 20 was formed by stacking the unit cell 6 and the separator plate 7 of FIG. In addition, in the case of such a configuration, the height of the fuel cell stack is actually increased by several millimeters by the amount of the unit cells 6 and the separator plate 7 constituting the additional battery section 20 at the upper and lower ends, It is not necessary to change the dimension of the structural material for such a slight height change.

In the fuel cell stack of the present embodiment having the above structure, the fuel gas flow passage 4 of each unit cell 6
As a result of inserting a thermocouple (not shown) and measuring the temperature, the results shown in FIG. 2 were obtained. In FIG. 2, the battery temperature of each of the sub-stacks 19 sandwiched between the cooling plates 8 is about 200 including the upper and lower sub-stacks 19.
It is 220 ° C., and the battery temperature of the additional battery part 20 added to the upper and lower ends is also about 200 to 220 ° C. That is, on one side of the additional battery unit 20 added to the upper and lower ends,
Although the cooling plate 8 is not arranged, the heat of the additional battery section 20 is absorbed by the structural material including the current collector plate 9, the insulating plate 10, the tightening plate 11 and the like adjacent to the cooling plate 8, and as a result, As a result, the entire battery temperature is about the same level of 200 to 220 ° C. This temperature is within a proper operating temperature range of the phosphoric acid fuel cell, which is within about 190 to 220 ° C.

Therefore, in this embodiment, the number of unit cells of the fuel cell stack is summed at the upper and lower ends while maintaining the cell temperature within an appropriate temperature range without increasing the number of cooling plates. It is possible to increase the number of sheets by four to increase the output per fuel cell stack. Further, since the number of cooling plates is not increased, the battery characteristics and compactness are excellent, and the cost per output can be significantly reduced. The cost reduction effect due to the increase in the number of unit cell stacks will be described below. More specifically, when the fuel cell stack of the present example is applied to the on-site type, 50 kW is obtained.
Description will be made in comparison with the on-site fuel cell stack.

That is, in general, in the 50 kW on-site type fuel cell stack, as in the conventional example of FIG. 10, six sub-stacks 19 each composed of six unit cells are stacked, and a total of 36 unit cells are formed. It is stacked. On the contrary,
In the on-site fuel cell stack of the present embodiment, as shown in FIG. 1, two unit cells are added to the upper and lower ends of the unit cell stack, and 40 unit cells are stacked as a whole. Will be done.

Here, the cell voltage of the 50 kW on-site type fuel cell stack is A [V / cell], and the current is B [A].
Then, the battery output is 36 AB [W]. Also,
The cell output of the on-site fuel cell stack of this example is
40 AB [W]. Therefore, the ratio of the battery output of the 50 kW on-site type to that of the present example is 40 AB / 36 AB = 1.1111.

When the cost of the 50 kW on-site type is C, the cost of one unit cell is 0.05 to C.
Since it is 0.1%, the cost of this embodiment is 1.002.
It is C to 1.004C. Therefore, the cost per battery output of this example is (1.002C to 1.004C) /1.111 = 0.902C to 0.904C. That is, according to the present embodiment, a significant cost reduction of 9.6 to 9.8% can be realized as compared with the 50 kW on-site type.

As described above, in the present embodiment, although the structure is simple, it is possible to greatly reduce the cost in the fuel cell stack having a small number of stacks such as on-site type, which is expected to have a great demand in the future. Is also very effective, and is also effective for a fuel cell power generation facility designed to obtain a high output by connecting a plurality of small capacity fuel cell stacks.

Next, a second embodiment according to the invention of claim 1 will be described. In the second embodiment, although not shown, each sub-stack 19 is composed of six unit cells 6 as in the first embodiment, and the cooling plates at the upper and lower ends of the unit cell stack are formed. Three unit cells 6 and a separator plate 7 were stacked between the battery 8 and the current collector plate 9 to form an additional battery unit 20. Note that, also in this embodiment, as in the case of the first embodiment, in actuality, the height of the fuel cell stack is equal to that of the unit cells 6 and the separator plate 7 constituting the additional battery section 20 at the upper and lower ends. Just a few millimeters higher, but similarly, no structural material resize is necessary.

In the fuel cell stack of this embodiment having the above structure, the temperature of each unit cell 6 was measured in the same manner as in the first embodiment, and the result shown in FIG. 3 was obtained. It was That is, also in this embodiment, the battery temperature levels of all the sub-stacks 19 sandwiched between the cooling plates 8 and the battery temperature levels of the additional battery parts 20 added to the upper and lower ends are set to about 200 to 220 ° C. , Which is within the proper operating temperature range.

Therefore, in this embodiment, the number of unit cells stacked in the fuel cell stack is summed at the upper and lower ends while maintaining the battery temperature within an appropriate temperature range without increasing the number of cooling plates. By increasing the number of sheets by 6, the output per fuel cell stack can be further increased as compared with the first embodiment. Further, since the number of cooling plates is not increased, the battery characteristics and compactness are excellent, and the cost per output can be significantly reduced.

Regarding the cost reduction effect due to the increase in the number of unit cell stacks, more specifically, in the case where the fuel cell stack of the present embodiment is applied to the on-site type,
Description will be made in comparison with the 50 kW on-site fuel cell stack. That is, in the same manner as the first embodiment, 50 kW
The cell voltage of the on-site fuel cell stack is A [V / ce
ll], and the current is B [A], the ratio of the battery outputs of the 50 kW on-site type and this example is 42AB / 36AB = 1.1666 ... When the cost of the 50 kW on-site type is C, the cost of this embodiment is 1.003C to 1.00.
Since it is 6C, the cost per battery output of the present embodiment is (1.003C to 1.006C) /1.167 = 0.859C to 0.862C. Therefore, according to this example, a significant cost reduction of 13.8 to 14.1% can be realized as compared with the 50 kW on-site type.

As described above, the present embodiment is different from the first embodiment in a fuel cell stack having a small number of stacks such as an on-site type, which is expected to have a great demand in the future, although the structure is simple. It is also extremely effective in that the cost can be drastically reduced, and is also effective in a fuel cell power generation facility designed to obtain a high output by connecting a plurality of small-capacity fuel cell stacks.

In the second embodiment as described above, the number of unit cells between the cooling plates 8 at the upper and lower ends and the structural material is increased, so that the thermal resistance is increased. In this case, the fuel cell temperature rise is
Since the hot water flowing in the cooling plate is used as the heat medium, the temperature rising time of the structural material becomes long.

(2) Embodiment of Invention of Claim 2 FIG. 4 is a diagram showing a third embodiment according to the invention of Claim 2. In the third embodiment, each of the sub-stacks 19a at the upper and lower ends of the unit cell stack has seven unit cells 6 respectively.
And the other central sub-stacks 19b are each composed of six unit cells 6. Specifically, in the fuel cell stacking process, seven unit cells are stacked only in the upper and lower sub-stacks 19a. Also in this case, the height of the entire fuel cell stack is actually several millimeters as much as the unit cells 6 and the separator plates 7 added to the sub-stacks 19a at the upper and lower ends, as in the above-described embodiments. Although it becomes higher, it is not necessary to change the dimensions of the structural material as in the above-mentioned embodiments.

In the fuel cell stack of this embodiment having the above-mentioned structure, the temperature of each unit cell 6 was measured in the same manner as in each of the above embodiments, and the result shown in FIG. 5 was obtained. .. That is, in the present embodiment, the battery temperature level of the upper and lower end sub-stacks 19a and the battery temperature level of the other central sub-stacks 19b are about 2
The same level of 00 to 220 ° C. can be used, and this temperature is within a proper operating temperature range.

Therefore, in this embodiment, the number of unit cells in the fuel cell stack is set to the number of subcells in the upper and lower end portions while maintaining the cell temperature within an appropriate temperature range without increasing the number of cooling plates. It is possible to increase the total number of sheets by two in the stack and increase the output per fuel cell stack. Further, since the number of cooling plates is not increased, the battery characteristics and compactness are excellent, and the cost per output can be significantly reduced.

Regarding the cost reduction effect due to the increase in the number of unit cell stacks, more specifically, in the case where the fuel cell stack of the present embodiment is applied to the on-site type,
Description will be made in comparison with the 50 kW on-site fuel cell stack. That is, the cell voltage of the 50 kW on-site type fuel cell stack was set to A [V / cel in the same manner as in each of the above Examples.
l] and the current is B [A], the 50 kW on-site battery output is 36 AB [W] as described above,
The battery output of this embodiment is 38 AB [W]. More strictly speaking, the total of 1s forming the upper and lower sub-stacks 20
Since the temperature of the four unit cells rises by about 10 ° C., the cell voltage becomes (A + 0.01) [V / cell]. Therefore,
Strictly speaking, the battery output of this embodiment is {24AB + 14.
(A + 0.01) B} [W]. As a result, 50k
The ratio of the battery output of the W on-site type and the battery output of this example is {24AB + 14 (A + 0.01) B} / 36AB. In this case, when the cell voltage A = 0.6 [V / cell], the battery output ratio is 1.062. And 5
Assuming that the cost of the 0 kW on-site type is C, the cost of this embodiment is 1.001C to 1.002C, and therefore the cost per battery output of this embodiment is (1.001C to 1.002C) / 1.062 = 0.943C to 0.944C. Therefore, according to this example, a significant cost reduction of 5.6 to 5.7% can be realized as compared with the 50 kW on-site type.

As described above, in the present embodiment, although the structure is simple, it is possible to greatly reduce the cost in the fuel cell stack having a small number of stacks such as on-site type, which is expected to have a great demand in the future. Is also very effective, and is also effective for a fuel cell power generation facility designed to obtain a high output by connecting a plurality of small capacity fuel cell stacks.

Next, a fourth embodiment according to the invention of claim 2 will be described. In the fourth embodiment, although not shown, the sub-stacks 19a at the upper and lower ends of the unit cell stack are formed.
And each of the other sub-stacks 19b in the central portion were each composed of 6 unit cells 6. Specifically, in the fuel cell stacking process, eight unit cells are stacked only in the upper and lower sub-stacks 19a. Also in this case, the height of the entire fuel cell stack is actually several millimeters as much as the unit cells 6 and the separator plates 7 added to the sub-stacks 19a at the upper and lower ends, as in the above-described embodiments. It will be higher,
As in the above-mentioned embodiments, it is not necessary to change the dimensions of the structural material.

In the fuel cell stack of this embodiment having the above-mentioned structure, the temperature of each unit cell 6 was measured in the same manner as in each of the above embodiments, and the result shown in FIG. 6 was obtained. .. That is, in this embodiment, the battery temperature level of the central sub-stack 19b is about 200 to 220 ° C. as in the third embodiment, while the battery temperature of the upper and lower sub-stacks 19a is lower. The temperature level was higher than that of the third embodiment, and the maximum temperature was as high as about 225 ° C. In this case, the margin for 230 ° C., which is the operating temperature limit of the phosphoric acid fuel cell, decreases,
Operation is possible by avoiding an operating method in which the battery temperature is likely to transiently increase, such as a sudden load increase.

Therefore, also in the present embodiment, the number of unit cells stacked in the fuel cell stack is set to the number of subcells at the upper and lower ends while maintaining the battery temperature within an appropriate temperature range without increasing the number of cooling plates. It is possible to increase the total number of sheets by four in the stack, and further increase the output per fuel cell stack as compared with the third embodiment. Further, since the number of cooling plates is not increased, the battery characteristics and compactness are excellent, and the cost per output can be significantly reduced.

The cost reduction effect by increasing the number of unit cell stacks will be described below. More specifically, the case where the fuel cell stack of the present embodiment is applied to an on-site type will be described.
Description will be made in comparison with the 50 kW on-site fuel cell stack. That is, if the cost ratio between the 50 kW on-site type and this example is obtained in the same manner as in each of the above examples, it can be seen that a substantial cost reduction of 10 to 11% can be realized by this example.

(3) Other Embodiments The present invention is not limited to the above-mentioned embodiments, but can be similarly applied to various fuel cells other than the on-site type, for example, a unit cell. The specific number of unit cells to be stacked between the upper and lower end portions of the stack and the structural material or added to the upper and lower end sub-stacks is appropriately selected according to the specific design specifications of the fuel cell. To be done.

[0044]

As described above, according to the present invention, a plurality of unit cells are stacked between the unit cell laminated body and the structural material at the upper and lower end portions, or the unit of the sub-stack at the upper and lower end portions is formed. By increasing the number of stacked cells than other sub-stacks, it is possible to increase the number of stacked unit cells with respect to the number of cooling plates.
It is possible to provide a highly practical fuel cell stack capable of increasing the output per fuel cell stack, excellent in cell characteristics and compactness, and capable of significantly reducing the cost per output.

[Brief description of drawings]

FIG. 1 is a schematic side view showing a laminated structure in an embodiment (first embodiment) of a fuel cell stack according to the invention of claim 1.

2 is a temperature distribution diagram of each unit cell in the fuel cell stack of FIG.

FIG. 3 is a temperature distribution diagram of each unit cell in a different embodiment (second embodiment) of the fuel cell stack according to the invention of claim 1.

FIG. 4 is a schematic side view showing a laminated structure in one embodiment (third embodiment) of the fuel cell stack according to the invention of claim 2.

5 is a temperature distribution diagram of each unit cell in the fuel cell stack of FIG.

FIG. 6 is a temperature distribution diagram of each unit cell in a different embodiment (fourth embodiment) of the fuel cell stack according to the invention of claim 2.

FIG. 7 is a perspective view showing a general configuration of a unit cell that constitutes a fuel cell.

FIG. 8 is an exploded perspective view showing a general configuration of a unit cell laminated body in which a plurality of unit cells shown in FIG. 7 are laminated.

FIG. 9 is an exploded perspective view showing the configuration of a general fuel cell stack.

FIG. 10 is a schematic side view showing an example of a laminated structure in a conventional fuel cell stack.

11 is a temperature distribution diagram of each unit cell in the fuel cell stack of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Matrix 2 ... Anode electrode 3 ... Cathode electrode 4 ... Fuel gas flow passage 5 ... Oxidant gas flow passage 6 ... Unit cell 7 ... Separator plate 8 ... Cooling plate 9 ... Current collecting plate 10 ... Insulating plate 11 ... Tightening plate 12 ... Terminal 13 ... Electrically insulating gasket 14-17 ... Manifold 18 ... Piping 19, 19a, 19b ... Sub-stack 20 ... Additional battery part

Claims (2)

[Claims] 1. A pair of electrodes are arranged with an electrolyte layer impregnated with a matrix sandwiched between them. Under the condition that a fuel gas flows through one electrode and an oxidant gas flows through the other electrode. A plurality of unit cells that output electric energy are stacked with a separator interposed therebetween, cooling plates are arranged at the upper and lower ends of the plurality of stacked unit cells, and cooling plates are inserted into the unit cells so that they are adjacent to each other. A unit cell laminated body in which a plurality of laminated unit cells are sandwiched as a sub-stack between cooling plates is formed, and a current collector plate, an insulating plate, and a tightening plate are further provided at the upper and lower ends of the unit cell laminated body. In a fuel cell stack including a structural member including the structure, a plurality of unit cells are stacked with a separator interposed between a cooling plate arranged at the upper and lower ends of the unit cell stack and the structural member. Forming an additional battery part Fuel cell stack, characterized in that. 2. A matrix is provided with a pair of electrodes sandwiching an electrolyte layer impregnated with an electrolyte, and a fuel gas flows through one electrode and an oxidant gas flows through the other electrode. A plurality of unit cells that output electric energy are stacked with a separator interposed therebetween, cooling plates are arranged at the upper and lower ends of the plurality of stacked unit cells, and cooling plates are inserted into the unit cells so that they are adjacent to each other. A unit cell laminated body in which a plurality of laminated unit cells are sandwiched as a sub-stack between cooling plates is formed, and a current collector plate, an insulating plate, and a tightening plate are further provided at the upper and lower ends of the unit cell laminated body. In a fuel cell stack formed by attaching a structural material including, the number of stacks of unit cells of the sub-stacks arranged at the upper and lower ends of the unit cell stack, the number of stacks of unit cells of the other sub-stacks in the center More than Fuel cell stack, characterized in that the.