JPH06338334A - Cooling plate and cooling system for fuel cell - Google Patents

Abstract

PURPOSE:To uniformly generate temperature distribution in a cell without taking a time in manufacture. CONSTITUTION:A cell layered unit, formed by laminating a plurality of sheets of cell 1, is provided with a cooling base board 4 mounted in a laminated condition and a cooling pipe 7 buried in this cooling base board 4 through a heat transfer charging material 6, and cooling water is circulated in the cooling pipe 7 to cool a cell main unit. In a cooling plate 3 of this fuel cell, a charge amount of the heat transfer charging material 6 is changed so as to uniformly obtain temperature distribution in accordance with temperature distribution in the single cell 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel cell cooling plate and cooling system for cooling a fuel cell, and more particularly to a fuel cell cooling plate and cooling system having improved cooling characteristics.

[0002]

2. Description of the Related Art A fuel cell supplies hydrogen, which is obtained by reforming natural gas or the like, and air, which is an oxidant, into the body of the fuel cell and causes an electrochemical reaction through an electrolyte such as phosphoric acid solution. To generate electric energy. In addition, an efficient energy generation system can be realized by recovering and utilizing the removed thermal energy when cooling the heat generated during power generation of the fuel cell with the cooling water.

Such a fuel cell has a laminated structure (cell stack structure) in which one unit cell (hereinafter referred to as a unit cell) having the power generation function is laminated.

FIG. 8 shows a cell stack structure of a fuel cell. The unit cell 1 of the fuel cell body comprises a matrix layer 11 holding an electrolyte, a fuel electrode 12 to which hydrogen as a fuel is supplied in the direction of arrow A, and an oxidant electrode 13 to which air is supplied in the direction of arrow B. And electrode base materials 14 and 15 with ribs
And a separator 16, and a large number of these single cells are stacked. Every time 5 to 10 single cells are stacked, a water-cooling type cooling plate 3 is stacked to form one sub-stack 2, and several tens of the sub-stacks 2 are stacked to form a cell stack. There is. The cell stack is held by fastening plates 17 provided at the top and the bottom.

As shown in FIG. 9, the cooling plate 3 has a cooling substrate 4 which can be divided into two upper and lower holders 4a and 4b, and a groove 5 provided in a layer of the cooling substrate 4, for example, as disclosed in Japanese Patent Laid-Open No. 61
No. 22573, JP-A-1-175173,
And a cooling pipe 7 made of metal, which is buried via a good heat-conducting filler 6 proposed in Japanese Patent Laid-Open No. 2-207458, and is formed in a meandering loop shape, for example.
As shown in FIG. 8, one end of the cooling pipe 7 is connected to a water supply header 8 and the other end thereof is connected to a drain header 9 via an insulating hose 10.

By the way, in a fuel cell using, for example, a phosphoric acid solution as an electrolyte, it is known that the phosphoric acid solution evaporates to some extent in a reaction gas, particularly in the air. Although this evaporation is slight, it reaches a considerable amount when the battery is operated for a long period of time, and in some cases, the battery cannot be operated.

One of the means for solving this problem is
For example, there is a cooling system for a fuel cell, which is disclosed in Japanese Patent Laid-Open No. 64-14876 and which can recover the evaporated phosphoric acid solution and return it to the cell. A cooling system for such a fuel cell is shown in FIG.

FIG. 10 shows a cooling water circulating portion for circulating cooling water in cooling plates 3 stacked for each sub-stack 2 of a fuel cell and a cooling pipe 7 embedded in the cooling plates 3 and formed in a meandering shape. 18 is shown. In FIG. 10, air flows in from the oxidant electrode inlet of the battery main body 1 adjacent to the cooling plate 3 (direction of arrow B) and flows out from the oxidant outlet (direction of arrow B1). In addition, the fuel hydrogen is
It flows in from the inlet of the fuel electrode (direction of arrow A), reverses the traveling direction at the return part of the outlet side and the return part of inlet side (directions of arrows A1 and A2, respectively) and flows out to the outlet of the fuel electrode (direction of arrow A3). .

In this fuel cell cooling system, the cooling pipe 7 in the cooling plate 3 stacked in the sub-stack 2 has a temperature sufficiently lower than the saturation temperature for a predetermined pressure in the cooling pipe 7 (for example, a saturation temperature of 180). In the case of 0 ° C., it is set to about 160 ° C. This will be referred to as a set temperature hereinafter), and cooling water that is a single-phase flow is supplied. The temperature of the cooling water, which is a single-phase flow, gradually rises while advancing in the cooling pipe 7, and boils when reaching the saturation temperature. The boiling cooling water becomes a gas-liquid two-phase flow when passing through the remaining cooling pipe 7, and flows from the drain header 9 through the cooling water outlet line 19 to the separator 20. Water and steam are separated by this separator 20, one steam flows through a steam line 21 to a reformer (not shown), and the other water is pressurized by a pump 22 and supplied to a cooling water circulation line 23.

The cooling water bypass line 24 is branched from the middle of the cooling water circulation line 23,
4 is provided with a heat exchanger 25. Further, the cooling water circulation line 23 and the cooling water bypass line 24 are connected to the three-way valve 2
6 is switchably connected.

The three-way valve 26 controls the water flowing through the cooling water circulation line 23 and the water flowing through the cooling water bypass line 24 so that the temperature of the cooling water flowing from the separator 20 to the cooling pipe 7 via the cooling water circulation line 23 is controlled. The temperature is controlled to reach the set temperature. For example, if the temperature of the cooling water flowing through the cooling water circulation line 23 is higher than the set temperature, the three-way valve 26
Increases the amount of cooling water flowing through the cooling water bypass line 24. Excessive heat of the cooling water flowing through the cooling water bypass line 24 is taken out as high temperature steam by the heat exchanger 25. If the temperature of the cooling water flowing through the cooling water circulation line 23 is lower than the set temperature, the cooling water bypass line 24
Reduce the amount of water flowing through. The water (single-phase flow) controlled to the set temperature in this way flows into the cooling pipe 7 again from the water supply header 8 through the cooling water inlet line 27 and is used for cooling.

Further, in order to replenish the steam component flowing to the reformer (not shown), water is supplied from the water supply tank 28 to the separator 20 by the water supply pump 29 via the water supply line 30.

In the fuel cell cooling system having such a structure, as shown in FIG. 11, a region (single-phase flow region, in the figure) from the cooling water, which is a single-phase flow, flowing into the cooling pipe 7 to boiling. L3) is a condensing region (phosphoric acid condensing region) in which the exhaust air after the reaction is cooled by the cooling water having a single-phase flow and the evaporated phosphoric acid is condensed.

The region (two-phase flow region, L4 in the figure) after the cooling water has boiled to form a two-phase flow is a region where an electrochemical reaction occurs (electrochemical reaction region), and is substantially Isothermally cooled.

Here, the cooling water is the cooling pipe 7 (L3, L4).
FIG. 12 shows the relationship between the time t and the temperature T when flowing through the inside. It should be noted that Δt3 is the time required for the cooling water to reach the saturation temperature T4 from the set temperature T3 as the cooling water passes through the cooling pipe 7 (time for passing through L3), and Δt4 is the gas-liquid two-phase flow region (L4 in the figure). It's time to pass. The cooling water at the set temperature T3 rises by ΔT to the saturation temperature T4 during Δt3, and is maintained at the same temperature (saturation temperature T4) during Δt4.

[0016]

During normal operation of a fuel cell, the reaction air supplied at room temperature cools the oxidizer electrode inlet side of the fuel cell sub-stack, and the reaction air gradually warms toward the outlet side. However, there is a drawback in that the heat transfer state changes due to the heat generation, resulting in an uneven temperature distribution within the unit cell. In order to solve this drawback, for example, it is disclosed in Japanese Patent Laid-Open No. 261073/1990 (FIG. 13).
It has been proposed to make the cooling pipe diameter thin on the oxidizer electrode inlet side and thicken it on the oxidizer outlet side to make the temperature distribution in the single cell uniform, as described above). Took a lot of time.

The uppermost and lowermost cooling plates of the cell stack are adjacent to the fastening plates, respectively. For this reason, the heat input to the cooling plate is halved compared to the other cooling plates, and the sub-stacks adjacent to the uppermost and lowermost cooling plates are overcooled correspondingly, resulting in deterioration of battery voltage characteristics.

On the other hand, in the cooling system of the fuel cell capable of recovering the phosphoric acid which is the electrolyte described above, since the phosphoric acid is condensed by the single-phase flow cooling, the temperature of the cooling water supplied to the cooling pipe is set to the set temperature. (The temperature was sufficiently lower than the saturation temperature) and the heat exchanger could not take out high temperature (temperature near the saturation temperature) steam.

Further, since the phosphoric acid is condensed by single-phase flow cooling, the cooling efficiency is poor and sufficient phosphoric acid cannot be recovered. In order to improve the phosphoric acid recovery effect, L3 must be widened, and as a result, L4 (electrochemical reaction region) is narrowed and the battery voltage characteristic deteriorates.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a cooling plate for a fuel cell in which the temperature distribution in a single cell is made uniform without labor in manufacturing.

Further, the present invention has been made in view of the above-mentioned circumstances, and it is possible to take out high-temperature steam above a set temperature without sacrificing the phosphoric acid recovery performance, and further improve the battery voltage performance. An object of the present invention is to provide a cooling system for a fuel cell that can be used.

[0022]

A cooling plate for a fuel cell according to the present invention is provided in order to solve the above-mentioned problems.
As described above, a cooling board mounted in a laminated state on a battery stack formed by stacking a plurality of single cells, and a cooling pipe embedded in the cooling board via a good heat filling material are provided. In a cooling plate of a fuel cell in which cooling water is circulated in the cooling pipe to cool the cell body, the filling amount of the good heat filling material is changed according to the temperature distribution in the single cell.

Further, in order to solve the above-mentioned problems, the cooling plate of the fuel cell according to the present invention is, as described in claim 2, between the cooling pipe on the inlet side of the oxidant and the cooling substrate. The filling amount of the good heat filling material to be filled is smaller than the filling amount of the good heat filling material to be filled between the remaining cooling pipe and the cooling substrate.

Further, in order to solve the above-mentioned problems, the cooling plate of the fuel cell according to the present invention is, as stated in claim 3, a cooling plate laminated on the uppermost and lowermost parts of the cell stack. The amount of good heat filling material to be filled is smaller than that of other cooling plates.

In order to solve the above-mentioned problems, the fuel cell cooling system according to the present invention, as set forth in claim 4, causes a fuel and an oxidant to react via an electrolyte to generate electric energy. A cooling system for a fuel cell for cooling a fuel cell, comprising a cooling plate having a cooling pipe embedded therein, and cooling the fuel cell by circulating cooling water in the cooling pipe, The cooling pipe is divided into a cooling pipe for cooling the fuel cell body and a cooling pipe for collecting electrolyte.

In order to solve the above-mentioned problems, the fuel cell cooling system according to the present invention uses, as described in claim 5, cooling water flowing through the electrolyte recovery cooling pipe.
A pressure control means for controlling the pressure of the cooling water is provided so as to form a phase flow.

Further, in order to solve the above-mentioned problems, the fuel cell cooling system according to the present invention, as set forth in claim 6, makes the temperature of the cooling water flowing into the fuel cell main body cooling pipe close to the saturation temperature. Therefore, the temperature control means for controlling the temperature of the cooling water is provided.

[0028]

FIG. 7 shows the temperature rise ΔTA state in the stacking direction (H) of the sub-stack due to the heat generated by the electrochemical reaction. In the figure, ΔT1 is the temperature difference between the cooling water temperature and the cooling pipe, ΔT2 is the temperature rise of the filler, ΔT3 is the temperature rise of the entire cooling plate, and ΔT3 is the temperature rise.
T4 is the temperature rise within the electrodes of the sub-stack.

According to FIG. 7, about 50% of the temperature rise in the sub-stack (single cell) is due to the cooling plate,
In particular, the filler accounts for about 80%. From this result, it is understood that the temperature of the sub-stack 2 (single cell) is changed by changing the filling amount of the filling material filled between the cooling plate and the cooling pipe. Therefore, by changing the filling amount of the good heat filling material based on the temperature distribution in the single cell, it is possible to make the temperature distribution in the single cell highly uniform without taking time and effort in manufacturing.

In particular, the filling amount of the good heat filling material filled between the cooling substrate and a part of the cooling pipe on the inlet side of the oxidizer is filled between the other cooling pipe and the cooling substrate. If the filling amount is smaller than the filling amount of the good heat filling material, it is effective because supercooling on the oxidant electrode inlet side can be suppressed.

When the amount of the good heat filling material filled in the cooling plates laminated on the uppermost and lowermost parts of the battery stack is smaller than that of the other cooling plates, the uppermost and lowermost sub-stacks are formed. Can be suppressed.

On the other hand, the cooling pipe embedded inside the cooling plate used in the fuel cell system is divided into one for cooling the fuel cell main body and one for electrolyte recovery. Then, the pressure control means controls the pressure of the cooling water flowing through the low-temperature cooling water circulation unit that circulates the cooling water in the electrolyte recovery cooling pipe, so that the cooling water becomes a gas-liquid two-phase flow at a temperature sufficiently lower than the saturation temperature. can do. Therefore, as compared with the conventional case, the electrolyte condensing ability is improved, the electrolyte recovery region can be narrowed (the electrochemical reaction region is widened), and the battery voltage characteristics can be greatly improved.

Further, the temperature of the cooling water flowing through the high temperature cooling water circulating portion for circulating the cooling water in the cooling pipe for cooling the fuel cell main body is controlled by the temperature control means so that the temperature of the cooling water becomes close to the saturation temperature. To do. As a result, high temperature steam near the saturation temperature can be taken out and energy efficiency is improved.

[0034]

Embodiments of the present invention will be described below with reference to the drawings. In addition, the same or equivalent components as those of the conventional example are designated by the same reference numerals, and the description thereof will be omitted or simplified.

A first embodiment will be described with reference to FIGS. 1 and 2.

FIG. 1 is a perspective view showing a schematic structure of a cooling plate of a fuel cell according to the present invention, and FIG. 2 is a sectional view taken along a division plane of a holder 4a and a holder 4b in FIG.

Cooling plate 3 of the fuel cell shown in FIGS. 1 and 2.
Is a groove 5 formed in a meandering shape on the cooling substrate 4 including the holders 4a and 4b (only the groove 5 formed in the holder 4b is shown in FIGS. 1 and 2), and the oxidant electrode inlet port is provided in the groove 5. The B side is intermittently provided, and the oxidant electrode outlet B1 side is provided with a meandering metal cooling pipe 7 which is buried via a good heat filling material 6 filled with high density.

The filling amount of the good heat filling material 6 in the intermittently filled portion and the intermittent filling rate are determined according to the uniformity of the temperature distribution.

Next, the operation will be described.

When the fuel cell provided with this cooling plate 3 is operated, the oxidant electrode inlet side B is largely cooled by the reaction air. However, since the filling amount of the filler 6 on the oxidant electrode inlet side B is reduced, the degree of temperature rise on the oxidant electrode inlet side B is increased, and the supercooling of the oxidant electrode inlet side B can be suppressed. As a result, the temperature distribution in the unit cell 1 can be made substantially uniform.

As another embodiment, the uppermost and lowermost cooling plates of the cell stack are filled with the good heat-filling material in a smaller amount than the other cooling plates as a whole. Alternatively, the filling amount in contact with the holder 4a side is discontinuous (low density), and the filling amount in contact with the holder 4b side is continuous (high density) (the holders 4a and 4b may be reversed). By doing so, the temperature of the sub-stack 2 adjacent to the uppermost (or lowermost) cooling plate 3 can be made substantially equal to the temperature of the other sub-stacks 2.

Further, the filling amount of the good heat filling material filled between the cooling plate 3 and the cooling pipe 7 at the uppermost and lowermost portions of the fuel cell is adjusted, and the cooling pipes 7 at the uppermost and lowermost portions are adjusted. It is effective to make the temperature of the sub stack 2 uniform by controlling the amount of cooling water supplied so as to be smaller than that of the other sub stacks 2.

Next, a second embodiment will be described with reference to FIGS.

FIG. 3 is a cooling system diagram of the fuel cell according to the present invention.

The cooling system for a fuel cell includes a cooling plate 3 laminated for each sub-stack 2 of the fuel cell, and this cooling plate 3
The cooling pipe 7 is embedded in the inside of the, and is provided with cooling pipes 7a and 7b formed in a meandering shape and divided into two. Of the divided cooling pipes 7a and 7b, the cooling pipe 7a located on the oxidizer electrode inlet side B is a cooling pipe for cooling the fuel cell body, which is located on the oxidizer electrode outlet side B1. The cooling pipe 7b is an electrolyte recovery cooling pipe for recovering phosphoric acid as an electrolyte.

In the cooling system for the fuel cell, the cooling water circulating portion 18 for cooling the fuel cell is used as the cooling water circulating portion 18 for circulating the cooling water through the divided cooling pipes 7a and 7b.
a and an electrolyte recovery cooling water circulation unit 18b.

The cooling water circulation 18a for cooling the fuel cell body for circulating cooling water through the cooling pipe 7a for cooling the fuel cell body includes a cooling pipe 7a for cooling the fuel cell body, a cooling water outlet line 19 connected to the cooling pipe 7a, A separator 20 for separating water and steam of the cooling water used for cooling the fuel cell body 1,
A cooling water circulation line 23 for circulating the water separated by the separator 20 is provided. The steam separated by the separator 20 is guided to the steam line 21 and flows out to a reformer (not shown).

A pump 22 as a power means is provided on the cooling water circulation line 23, a cooling water bypass line 24 branched from the cooling water circulation line 23 on the downstream side of the pump 22, and a cooling water bypass line 24 are provided on the cooling water bypass line 24. The heat exchanger 25 and the three-way valve 26 provided at the confluence of the cooling water circulation line 23 and the cooling water bypass line 24 are provided.

On the other hand, the cooling water circulation unit 18a is provided with a temperature detector 31 for detecting the temperature of the cooling water flowing out from the separator 20. The temperature detection signal of the temperature detector 31 is sent to the control unit 32, and the control unit 32 can control switching of the three-way valve 26 based on the temperature detection signal.

The cooling water flowing out from the three-way valve 26 flows through the cooling water inlet line 27 and flows into the fuel cell cooling cooling pipe 7a again, and the electrolyte recovery line 33 of the electrolyte recovery cooling water circulating portion 18b. After that, it is divided into those flowing out to the electrolyte recovery cooling pipe 7b.

On the electrolyte recovery line 33, a regulating valve 34 for controlling the pressure of the cooling water flowing on the electrolyte recovery line 33 is provided, and the cooling water via the regulating valve 34 is fed to the electrolyte recovery cooling pipe 7b. It is configured to flow in. The adjustment valve 34 includes a drive unit 3 that drives the adjustment valve 34.
5 and a control unit 36 for controlling the drive output of the drive unit 35 are provided, and constitute pressure control means 37.

The outflow side of the electrolyte recovery cooling pipe 7b is connected to the cooling water outlet line 38. The cooling water flowing through the cooling water outlet line 38 flows out to the water supply tank 28 via the heat exchanger 39. Further, in order to replenish the amount of steam flowing to the reformer (not shown), water is supplied from the water supply tank 28 to the separator 20 by the water supply pump 29 via the water supply line 30. The separator 20 repeats the above-described operation and sends the cooling water to the cooling water circulation line 23 so that the cooling water circulates through the cooling pipe 7a for cooling the fuel cell main body and the cooling pipe 7b for collecting electrolyte.

The cooling water circulation line 23, the cooling water bypass line 24, the heat exchanger 25, the three-way valve 26, the temperature detector 31, and the control section 32 constitute a temperature control means 40.

Next, the operation will be described.

In this fuel cell cooling system, a cooling pipe 7 for cooling the fuel cell, a cooling pipe 7a for cooling the fuel cell, and an electrolyte recovery cooling pipe 7b for recovering phosphoric acid as an electrolyte are provided. And the cooling water near the saturation temperature of the cooling water (the saturation temperature of the predetermined pressure in the cooling pipe 7a, which is 180 ° C. in this embodiment) is supplied to the cooling pipe 7a for cooling the fuel cell, Cooling water that is a gas-liquid two-phase flow near the set temperature (160 ° C. in this embodiment) can be supplied to the electrolyte recovery cooling pipe 7b.

Now, the cooling water (temperature: 180 ° C.) used for cooling the fuel cell flows into the separator 20 through the cooling water outlet line 19. The separator 20 separates the inflowing cooling water into water and steam, and the cooling water from which the steam component has been separated is pressurized by the pump 22 and flows through the cooling water circulation line 23, while one of the cooling water directly flows into the three-way valve 26. The other flows through the cooling water bypass line 24 and flows into the three-way valve 26 via the heat exchanger 25.

On the other hand, the temperature detecting section 31 constantly detects the temperature of the cooling water flowing out of the separator 20 and sends this detection information to the control section 32.

The control unit 32 always lowers the temperature of the cooling water flowing out from the three-way valve 26 by 3 to 5 ° C. with respect to the temperature (saturation temperature) detected by the temperature detection unit 31 (this temperature is set as the target temperature, The valve of the three-way valve 26 is adjusted so that the temperature is 175 ° C. in this embodiment). By adjusting the valve of the three-way valve 26, the amount of cooling water directly flowing through the cooling water circulation line 23 and flowing directly to the three-way valve 26 and the amount of cooling water flowing through the cooling water bypass line 24 are determined.

For example, when the temperature detected by the temperature detector 31 is lower than 175 ° C., the amount of cooling water flowing directly from the separator 20 to the three-way valve 26 is increased, and conversely the temperature detected by the temperature detector 31 is 175 ° C. When it is higher than 0 ° C., the amount of cooling water flowing through the cooling water bypass line 24 is increased. That is, by controlling the amount of cooling water exhausted by the heat exchanger 25, cooling water near the saturation temperature of about 175 ° C. is always obtained, and at the heat exchanger 25, high temperature steam near the target temperature of 175 ° C. is generated. You can take it out.

On the other hand, the cooling water in the vicinity of 175 ° C. flowing out from the three-way valve 26 is diverted, and one is the cooling pipe 7 for cooling the fuel cell.
The fuel cell 1 is supplied again for cooling the fuel cell 1. The other split cooling water flows out to the electrolyte recovery line 8b and flows into the adjustment valve 34.

The adjusting valve 34 is squeezed by the drive unit 35 being driven based on a control signal from the control unit 36, so that the pressure of the cooling water flowing out of the adjusting valve 34 is set to a predetermined temperature from the predetermined pressure. The pressure is reduced to a set pressure so that a gas-liquid two-phase flow is generated in the vicinity.

As a result, the cooling water supplied to the electrolyte recovery cooling pipe 7b becomes a two-phase flow of about 160.degree.

FIG. 4 shows a phosphoric acid condensation region L1 and an electrochemical reaction region L2 in such a fuel cell cooling system.
Shown in. The phosphoric acid condensation region L1 for cooling the exhaust air after the reaction to condense phosphoric acid and the electrochemical reaction region L2 for cooling the battery body 1 are both gas-liquid two-phase flow regions and are substantially isothermally cooled. .

The time t when flowing through the cooling pipes 7a (L2) and 7b (L1) of such a fuel cell cooling system.
The relationship between the temperature and the temperature T is shown in FIG. In addition, T1 is a set temperature (160 degreeC) and T2 is a saturation temperature (180 degreeC). Further, Δt1 is the time for the cooling water to pass through the cooling pipe 7b (L1 in the figure), and Δt2 is the time for the cooling water to pass through the cooling pipe 7a (L2 in the figure).

As can be seen by comparing FIG. 5 and FIG. 12, since the electrolyte recovery can be carried out by a gas-liquid two-phase flow, the phosphoric acid condensing capacity is improved. As a result, since the phosphoric acid condensation region L1 can be set narrower (Δt1 <Δt3) than in the conventional case, the electrochemical reaction region L2 can be set wider (Δt2> Δt4) and the battery voltage characteristics can be greatly improved. You can

A third embodiment of the present invention is shown in FIG.

FIG. 6 shows a cooling system for a fuel cell in this embodiment. In this embodiment, the cooling water outlet line 38
Is connected to the cooling water circulation line 23 via the pump 41. Since the other points are the same as those of the second embodiment, the description thereof will be omitted.

In the present embodiment, the cooling water used for cooling the exhaust air in the electrolyte recovery cooling pipe 7b is pressurized by the pump 41 and flows through the cooling water outlet line 38 to flow in the cooling water circulation line 23.
Flow into. With this configuration, the cooling water having the exhaust heat energy by cooling the exhaust air can be supplied to the cooling pipe 7a for cooling the fuel cell main body, and the exhaust heat energy can be used more effectively. .

In the second and third embodiments, the three-way valve is used as a part of the temperature control means, but the present invention is not limited to this. For example, a cooling water circulation line and a cooling water bypass. Even if the flow control valves are individually provided on the line upstream of the confluence of the lines, the second embodiment and the third embodiment
The same effect as that of the embodiment can be obtained.

[0070]

As described in detail above, according to the cooling plate for a fuel cell of the present invention, a cooling board mounted in a stacked state on a battery stack formed by stacking a plurality of single cells, A cooling plate of a fuel cell that includes a cooling pipe embedded in a cooling substrate via a good heat filling material and circulates cooling water in the cooling pipe to cool the cell body. Since it was changed according to the temperature distribution in the cell,
It is possible to make the temperature distribution within the unit cell highly uniform without the need for manufacturing.

In the cooling plate of the fuel cell according to the present invention, the filling amount of the good heat filling material filled between the cooling pipe on the inlet side of the oxidant and the cooling substrate is set to the remaining cooling pipe and the cooling substrate. Since it is smaller than the filling amount of the good heat filling material filled in between, the supercooling on the oxidant electrode inlet side can be suppressed, and the temperature distribution in the single cell can be made highly uniform.
Further, the cooling plate of the fuel cell according to the present invention has the best heat-packing material filled in the cooling plates laminated on the uppermost part and the lowermost part of the cell stack as compared with other cooling plates. Also, it is possible to suppress supercooling of the lowermost sub-stack, and it is possible to make the temperature distribution within the single cell highly uniform.

The fuel cell cooling system according to the present invention is a fuel cell cooling system for cooling a fuel cell that reacts a fuel and an oxidant through an electrolyte to generate electric energy, and includes a cooling pipe. In a cooling system for a fuel cell, which includes a cooling plate embedded inside and cools a fuel cell by circulating cooling water in the cooling pipe, the cooling pipe includes a cooling pipe for cooling a fuel cell body and a cooling pipe for collecting electrolytes. And a pressure control means for controlling the pressure of the cooling water so that the cooling water flowing through the electrolyte recovery cooling pipe becomes a gas-liquid two-phase flow. The rising electrolyte recovery region can be narrowed (the electrochemical reaction region is widened), and the battery voltage characteristics can be greatly improved.

Further, the fuel cell cooling system according to the present invention is a fuel cell cooling system for cooling a fuel cell which reacts a fuel and an oxidant through an electrolyte to generate electric energy. In a cooling system for a fuel cell, which includes a cooling plate embedded inside and cools a fuel cell by circulating cooling water in the cooling pipe, the cooling pipe includes a cooling pipe for cooling a fuel cell body and a cooling pipe for collecting electrolytes. And a temperature control means for controlling the temperature of the cooling water so that the temperature of the cooling water flowing into the cooling pipe of the fuel cell main body becomes close to the saturation temperature. It can be taken out and the energy efficiency can be improved.

[Brief description of drawings]

FIG. 1 is a schematic perspective view showing an embodiment of a cooling plate for a fuel cell according to the present invention.

FIG. 2 is a cross-sectional view of a split surface of a holder 4a and a holder 4b in FIG.

FIG. 3 is a diagram showing a schematic configuration of a second embodiment of a cooling system for a fuel cell according to the present invention.

FIG. 4 is a diagram showing an electrochemical reaction region and a phosphoric acid recovery region of the cooling plate in FIG.

FIG. 5 is a graph showing a relationship between time and temperature of cooling water flowing in a cooling pipe.

FIG. 6 is a diagram showing a schematic configuration of a third embodiment of the fuel cell cooling system according to the present invention.

FIG. 7 is a graph showing a temperature distribution in the stacking direction of a single cell.

FIG. 8 is a diagram showing the structure of a sub-stack (single cell) of a fuel cell.

FIG. 9 is a sectional view showing a conventional cooling plate.

FIG. 10 is a diagram showing the configuration of a conventional fuel cell cooling system.

FIG. 11 is a view showing an electrochemical reaction region and a phosphoric acid recovery region of a conventional cooling plate.

FIG. 12 is a graph showing a relationship between time and temperature of cooling water flowing in a conventional cooling pipe.

FIG. 13 is a view showing a conventional example of a structure of a cooling pipe embedded in a cooling plate.

[Explanation of reference numerals] 1 single cell 2 sub-stack 3 cooling plate 4 cooling substrate 4a, 4b holder 5 groove 6 good heat conductor 7 cooling pipe 7a fuel cell cooling cooling pipe 7b electrolyte recovery cooling pipe 18a, 18b cooling water circulation unit 19 Cooling water outlet line 20 Separator 21 Steam line 22 Pump 23 Cooling water circulation line 24 Cooling water bypass line 25 Heat exchanger 26 Three-way valve 27 Cooling water inlet line 28 Water supply tank 29 Pump 30 Water supply line 31 Temperature detector 32 Electrolyte recovery line 33 Control unit 34 Regulator valve 35 Drive unit 36 Control unit 37 Pressure control means 38 Cooling water outlet line 39 Heat exchanger 40 Temperature detection means 41 Pump B Oxidizing agent inflow direction B1 Oxidizing agent outflow direction

Claims (6)

[Claims] 1. A cooling board, which is attached in a stacked state to a battery stack formed by stacking a plurality of single cells, and a cooling pipe embedded in the cooling board via a good heat filling material. In the cooling plate of the fuel cell for cooling the cell body by circulating cooling water in the cooling pipe, the filling amount of the good heat filling material is changed according to the temperature distribution in the single cell. Cooling plate. 2. The filling amount of the good heat filling material, which is filled between the cooling pipe on the inlet side of the oxidant and the cooling substrate,
The cooling plate for a fuel cell according to claim 1, wherein the cooling amount is smaller than the filling amount of the good heat filling material filled between the remaining cooling pipes and the cooling substrate. 3. The cooling of a fuel cell according to claim 1, wherein the cooling plates stacked on the uppermost part and the lowermost part of the cell stack have a smaller amount of good heat filling material than other cooling plates. Board. 4. A cooling system for a fuel cell, which cools a fuel cell that reacts a fuel and an oxidant through an electrolyte to generate electric energy, comprising a cooling plate having a cooling pipe embedded therein. In a fuel cell cooling system for cooling a fuel cell by circulating cooling water in the cooling pipe, the cooling pipe is divided into a cooling pipe for cooling the fuel cell body and a cooling pipe for collecting electrolytes. Battery cooling system. 5. The cooling system for a fuel cell according to claim 4, further comprising pressure control means for controlling the pressure of the cooling water so that the cooling water flowing through the electrolyte recovery cooling pipe becomes a gas-liquid two-phase flow. . 6. The temperature control means for controlling the temperature of the cooling water so that the temperature of the cooling water flowing into the cooling pipe of the fuel cell main body becomes close to the saturation temperature, as claimed in claim 4 or claim 5. Fuel cell cooling system.