JPH05144449A - Fuel cell - Google Patents

Abstract

PURPOSE:To simplify the stacked structure of a fuel cell equipped with cooling plates and enhance the battery performance by furnishing mamifolds for refrigerant within separator plates. CONSTITUTION:A plurality of manifolds 19, 20 for refrigerant 9 are furnished at the perimeter of a stack of separators 13 of a stacked type fuel cell 1. Each cooling plate 14 is furnished internally with passages for the refrigerant, and a plurality of through holes are bored at the perimeter of the stack while communications are taken to the two ends, wherein the number is selected appropriately. According to this arrangement, the structure of the fuel cell 1 clan be simplified, and also the cooling performance is enhanced, which permits achieving enhancement of the battery performance, lifetime, and reliability. As the refrigerant, oxidating agent gas may be used, and its reuse allows the fuel cell to exert a high thermal efficiency in power generation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel cell, and more particularly to a fuel cell which facilitates supply and discharge of a cooling medium to the cell body.

[0002]

2. Description of the Related Art In a fuel cell, an anode and a cathode are arranged with an electrolyte plate sandwiched therebetween to form a unit cell, and a fuel gas and an oxidant gas are supplied to the anode and the cathode to generate electricity electrochemically. It is a thing. It is common to stack a large number of unit cells, and a separator is inserted between the unit cells to separate adjacent anodes and cathodes. Since the chemical reaction of the fuel cell during power generation is an exothermic reaction, cooling is required when a large number of layers are stacked.

A general cooling method for a conventional fuel cell is, for example, a phosphoric acid fuel cell disclosed in Japanese Utility Model Laid-Open No. 2-27503, in which an appropriate number of unit cells are laminated to form a cooling plate and the unit cells are laminated. This is a method of keeping the temperature rise of the battery at a specified temperature by removing the heat in the direction. A pipe for a cooling medium is attached to the cooling plate from the outside of the laminated battery main body to supply and discharge the cooling medium. This structure can expect good results from the aspect of cooling effect, but since the cooling medium supply and discharge pipes are attached from the outside of the laminated battery main body, the side surface of the laminated battery increases when the number of cooling plates increases. A large number of pipes are provided in the structure, which results in a complicated structure. In addition to the thermal expansion of the piping itself due to temperature, it is necessary to consider a structure that follows changes in the stack height of the stacked battery due to expansion due to heat generation of the stacked battery, contraction due to load, etc. However, if a flexible portion is provided in each pipe in order to solve this problem, the structure of the pipe system becomes more complicated.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a fuel cell which has a simple structure of a cooling system for a laminated battery and which has a simple structure and has a high cooling effect and a high heat generation efficiency.

[0005]

In order to achieve the above object, a unit cell composed of an electrolyte plate having an anode plate and a cathode plate arranged on one side and a separator plate are alternately laminated, and the separator is Flow paths for fuel gas and oxidant gas are formed on both sides of the separator plate, and a plurality of through holes are formed along the stacking direction at the sides of the stack of the electrolyte plate and the separator plate. In a fuel cell in which holes are respectively connected to the flow paths of the fuel gas and the oxidant gas of the separator plate, a plurality of cooling plates having cooling medium flow paths inside are installed in the laminate, and the cooling is performed. The fuel cell is characterized in that a plurality of through holes are formed in the side portion of the laminated body of the cooling plate so as to communicate with both ends of the medium flow path.

A fuel gas / oxidant gas / cooling medium supply / discharge space partition is provided at a side portion, and a header having a through hole is provided in the partition so as to communicate with the through hole of the separator plate. It is desirable to provide it at the end or in the middle.

The cooling medium channel may be a void formed over the entire surface of the effective electrode, and a porous plate may be inserted into the void so as to block the flow of the cooling medium, or the void may be formed on the plate surface. A plate having a plurality of through holes may be attached.

Further, the cooling medium flow path may be composed of a plurality of through holes arranged with a gap over the entire surface of the effective electrode.

The flow direction of the cooling medium may be opposite to the flow direction of the fuel gas or the oxidant gas. Further, the cooling medium may be an oxidant gas, and the oxidant gas as a cooling medium discharged from the laminated fuel cell may be supplied into the oxidant gas inlet side pipe.

[0010]

With this structure, the object of the present invention can be achieved by the following operation according to the present invention.

The cooling medium supplied from the outside to the cooling medium supply space partition provided in the header for fastening the stacked cells at appropriate positions of the stacked cells is supplied from the manifold provided correspondingly to the separator. Spill into the manifold of the board. The cooling medium passes through the manifolds of the plurality of separators and reaches the cooling plate, where a part of the cooling medium flows into the space between the fuel gas and the oxidant gas flow path side plate of the cooling plate. The cooling medium that has flowed into the space deprives the anode and cathode of heat generation via the side plate, returns from the discharge manifold at the other end to the header through the manifold of each separator, and is discharged to the outside from the discharge space partition of the header. To be done.

In this way, supply of the cooling medium to each cooling plate
Evacuation is performed at the separator and cold plate manifold.
Thereby, the piping for supplying / discharging the cooling medium to / from the laminated battery is provided only in the header of the laminated battery, and the structure of the entire battery can be simplified.

Further, by making the flow direction of the cooling medium in the cooling plate to be opposite to the flow direction of the fuel gas or the oxidant gas, the heat generation reaction on the electrode surface causes the temperature of the fuel gas to be increased on the downstream side. Alternatively, heat can be exchanged between the oxidant gas and the cooling medium that has not risen in temperature before the heat exchange, that is, in a state where the temperature difference is large, and the heat transfer coefficient is improved.

Further, a perforated plate is provided in the space inside the cooling plate to diffuse the cooling medium, or a cooling medium flow path is provided between the fuel gas and oxidant gas flow paths of the separator. The use of such a cooling plate improves the heat transfer coefficient of the cooling medium and is preferable in terms of the cooling effect.

On the other hand, when an oxidant gas is used as a cooling medium to be supplied to the fuel cell, and after cooling, the oxidant gas as a cooling medium discharged from the fuel cell is supplied into the oxidant gas inlet side pipe, The energy required to raise the temperature of the oxidizing gas supplied to the cell by raising the temperature close to the operating temperature is saved, and the overall heat generation efficiency of the fuel cell is improved.

[0016]

EXAMPLE An example of the present invention will be described.

FIG. 1 is a perspective view of the whole laminated fuel cell according to one embodiment of the present invention, and the laminating direction is shown in cross section for the purpose of internal description. At the lower end of the laminated fuel cell 1, there is a header-2 for supplying / exhausting gas to / from the laminated fuel cell 1 from the outside or from the laminated fuel cell 1. An air supply pipe 4 and an exhaust pipe 5 for the oxidant gas 3, an air supply pipe 7 and an exhaust pipe 8 for the fuel gas 6, and a supply pipe 10 and an exhaust pipe 11 for the cooling medium 9 are attached to the header-2. Although not shown on both sides, an electrolyte plate 12 and a separator plate 13 having an anode and a cathode (hereinafter collectively referred to as electrodes) arranged on the header-2 are alternately laminated to form one laminated battery. Is configured.

In such a fuel cell, for example, in the case of a molten carbonate fuel cell, its operating temperature is 650 ° C.
The fuel gas and the oxidant gas are caused to flow in at a value close to the temperature. Then, electricity is generated by an electrochemical reaction between the fuel gas and the oxidant gas inside the cell, and at this time, reaction heat is generated. The heat generation distribution on the electrode surface is not always uniform, and therefore the temperature distribution on the electrode is non-uniform. If the electrode temperature distribution becomes non-uniform, it will adversely affect the performance, life and reliability of the battery. Therefore, the cooling plate 14 for making the temperature distribution of the laminated battery 1 uniform in the laminated battery.
Is provided in an appropriate number. The stacking position and the number of stacks of the cooling plates 14 are appropriately determined depending on the total number of stacks of the battery and the size thereof so that the battery temperature is maintained at a predetermined temperature.

The oxidant gas 3 and the fuel gas 6 supplied from the outside flow into the plenum chamber in the header-2,
From there, these gases flow into manifolds 15 and 16 provided for supplying each unit cell, and are distributed to each unit cell. Then, after power generation by an electrochemical reaction in each unit cell, a mixed gas of fuel gas and generated gas,
The remaining oxidant gas flows into the exhaust manifolds 17 and 18, and after entering the plenum chamber in the header-2,
The exhaust pipes 8 and 5 flow out of the battery. Also, the cooling plate 1
The cooling medium 9 to be supplied to the cooling medium 4 is also first supplied to the plenum chamber in the Hetzda-2, then flows into the cooling medium supplying manifold 19 and then distributed to the plurality of cooling plates 14, and again to the cooling medium discharging manifold 20. After flowing in and entering the plenum chamber in Header-2, exhaust pipe 11
Are discharged to the outside.

FIG. 2 shows a cooling plate as an embodiment of the present invention. FIG. 2A is a plan view showing a flow path on the cathode surface side of the cooling plate 14. As shown in the figure, the cooling plate 14 is similar to the other separator plates in that the oxidizing gas 15, 18 and the fuel gas 16, 17 and the cooling medium manifolds 19, 2 are used.
0 is provided. On the upper surface, the oxidant gas 3 flows in from the manifold 15 and flows out from the manifold 18, as shown by the flow direction 26 of the arrow. FIG. 2B is a sectional view taken along the line AA of FIG. As shown in the figure, an upper partition plate 24 forming an oxidant gas flow channel surface 21 and a fuel gas flow channel surface 22
The flow path 23 for the cooling medium is provided between the lower partition plates 25 forming The cooling medium 9 flows into this flow path from the cooling medium supply manifold 19, and while exchanging heat with the upper and lower partition plates 24 and 25 while flowing through the flow path 23,
Outflow from the exhaust manifold 20. 2 (c) is shown in FIG.
FIG. 6B is a BB view showing the plane of the flow path 23 of the cooling medium 9. The flow of the cooling medium 9 is as shown in FIG.
(A) It is preferable to reverse the flow direction 26 of the oxidant gas 3. The material of this cooling plate is similar to that of the separator plate.For example, in the case of a molten carbonate fuel cell, a material such as stainless steel that withstands the atmosphere of molten carbonate, fuel gas, oxidant gas, etc. at high temperature is used. There is. Partition board 2
4 and 25 may be manufactured by welding at a predetermined interval to a frame plate forming a manifold group.

FIG. 3 shows the analysis result of the temperature distribution on the separator surface in the conventional fuel cell when the cooling plate is not used. As shown in the figure, the temperature in the outflow direction of the oxidant gas is high in the separator plate surface. Become. This is because although heat is generated in the battery due to an electrochemical reaction as described above, this heat is transmitted in the downstream direction by the flow of the oxidant gas. Therefore, as shown in FIG. 2C, by setting the cooling medium 9 in the direction opposite to the flow direction 26 of the oxidant gas, the cooling medium 9 flows in from the direction in which the temperature is high, so that a larger cooling effect is obtained. You can expect it.

FIG. 4 shows the structure of the header 2 of the fuel cell according to one embodiment of the present invention. The outer shape is viewed from above, and has strength such that stacked batteries can be loaded or tightened. The material is similar to the cold plate described above.
As shown in FIG. 1, the header 2 is provided with various supply / exhaust pipes and corresponding plenum chambers for the fuel gas 27, the oxidant gas 28, and the cooling medium 29.

FIGS. 5 (a) and 5 (b) show a cooling plate according to another embodiment of the present invention, and FIG. 5 (a) is the same as that of FIG. The plane is shown in FIG.
(B) has shown the cross section in CC of Fig.5 (a). A perforated plate 30 for diffusing the cooling medium is provided in the cooling medium flow path 23 in the cooling plate 14. According to the present embodiment, the cooling medium 9 that has flowed into the flow path 23 has the porous plate 3
When it is 0, the heat is diffused to the entire surface in the cooling plate, the heat exchange with the separator plate partition plates 24 and 25 is further increased, and the effect of cooling the heat generation at the anode and the cathode can be increased. The shape and mounting position of the porous plate 30 are determined by the shape and size of the fuel cell, the flow rate of the cooling medium 9, and the like. If one end of the porous plate 30 is previously fixed to the partition plate 24 or 25 by welding or the like, the other end is not necessarily fixed. Alternatively, both ends may be fixed to the partition plates 24 and 25 within a workable range.

FIG. 6 is also another embodiment of the present invention, which is shown in FIG.
The cooling plate sectional drawing in the same position as is shown. The configuration of the cooling plate 14 is a cooling plate 32 having a cooling medium passage 31. In the embodiment, the cooling medium flowing into the space of the cooling plate cools the cooling plate through the air in the space, and since the heat transfer coefficient is small, the amount of heat transfer from the cooling plate to the cooling medium is small. The cooling effect is also small. Therefore, by constructing the cooling plate 14 using the cooling plate 32 as in the present embodiment, it is possible to obtain a cooling plate having a large amount of heat transfer in the cooling plate and a greater cooling effect as compared with the above-described embodiment. Become.

As described above, according to the present embodiment, since the manifold inside the separator plate is used as the flow path of the cooling medium for cooling the fuel cell, no dedicated pipe group is required outside, and therefore the fuel Not only the structure of the entire battery becomes simpler, but also the cooling effect can be increased.
It is possible to obtain a fuel cell having excellent performance, life and reliability.

FIG. 7 is also a plan view of the header 2 of the fuel cell showing another embodiment of the present invention. The cooling medium supplied to the cooling plate is discharged from the cooling plate, recovered, and then used again as the oxidant gas of the battery. Figure 7
As described above, the discharge pipe 11 for the cooling medium 9 is connected to the oxidant gas supply pipe 4. Since the cooling medium 9 flowing through the cooling plate is a high temperature gas due to heat exchange in the cooling plate, it is possible to supply it as it is without the need of heating it as an oxidant gas. Can be used effectively. According to this embodiment, in addition to the effects of the above-described embodiments, an economically excellent fuel cell can be obtained.

[0027]

According to the present invention, the piping system for the cooling medium can be simplified, so that the structure of the fuel cell provided with the cooling plate can be simplified and the cooling performance can be improved. It has the effect of improving the performance, life and reliability of the battery.

Further, by using the oxidant gas as the cooling medium and reusing it, the heat generation efficiency of the power generation can be improved, which is economically effective.

[Brief description of drawings]

FIG. 1 is a perspective view of the overall structure of an embodiment of the present invention.

FIG. 2A is a plan view of a cooling plate of one embodiment, and FIG.
Is a longitudinal section and (c) is a surface showing an internal structure.

FIG. 3 is a diagram showing an example of a separator temperature distribution of a conventional fuel cell.

FIG. 4 is a view showing a header plane of an embodiment of the present invention.

5A is a plan view and FIG. 5B is a cross section of a cooling plate according to another embodiment of the present invention.

FIG. 6 is a view showing a cross section of a cooling plate according to another embodiment of the present invention.

FIG. 7 is a plan view of a header according to another embodiment of the present invention.

[Explanation of symbols]

 1 Laminated Fuel Cell 2 Header 10 Cooling Medium Supply Pipe 11 Cooling Medium Discharge Pipe 12 Electrolyte Plate 13 Separator Plate 14 Cooling Plate 19 Cooling Medium Supply Manifold 20 Cooling Medium Discharging Manifold 30 Perforated Plate 32 Cooling Plate

Claims (8)

[Claims] 1. A unit cell composed of an electrolyte plate having an anode plate and a cathode plate arranged on one side and a separator plate are alternately laminated, and a fuel gas and an oxidant gas are respectively provided on both surfaces of the separator plate. A plurality of through holes are formed along the stacking direction on the side of the laminate of the electrolyte plate and the separator plate, and the plurality of through holes are respectively used as fuel gas for the separator plate. In a fuel cell connected to a flow path of an oxidant gas, a plurality of cooling plates having a cooling medium flow path inside are installed in the laminate, and the cooling plates are connected to both ends of the cooling medium flow path to communicate with each other. A fuel cell, characterized in that a plurality of through holes are formed in the side portion of the laminate of the plate. 2. The fuel gas / oxidant gas / cooling medium supply / exhaust space partition portion according to claim 1, wherein the partition portion communicates with the through hole of the separator plate to form a through hole. A fuel cell comprising the header having the header provided at an end or in the middle of the laminate. 3. The fuel cell according to claim 1, wherein the cooling medium passage is a void portion formed over the entire surface of the effective electrode. 4. The fuel cell according to claim 3, wherein a perforated plate is inserted into the void so as to block the flow of the cooling medium. 5. The fuel cell according to claim 1, wherein the cooling medium flow path is composed of a plurality of through holes which are arranged with a gap over the entire surface of the effective electrode. 6. The fuel cell according to claim 3, wherein a plate having a plurality of through holes extending along the plate surface is mounted in the void portion. 7. The fuel cell according to claim 1, wherein the flow direction of the cooling medium is opposite to the flow direction of the fuel gas or the oxidant gas. 8. The method according to claim 1, wherein the cooling medium is the oxidant gas, and the oxidant gas as a cooling medium discharged from the laminated fuel cell is supplied into an oxidant gas inlet side pipe. Is a fuel cell.