JPH06243883A - Cooling device for fuel cell - Google Patents

Abstract

PURPOSE:To enable cooling water to be supplemented to a cooling loop with neither degradation of cell performance nor damage made due to fluctuation in cooling water temperature by supplementing cooling water to the cooling loop through a steam separator from the outside. CONSTITUTION:A cooling loop is made up of a circulation pump 3, take-off piping and a valve 8 for blow-down, and of a steam separator 4. Cooling water supplement piping which runs from a refilling pump 1 suplementing cooling water from the outside to the inlet port of the pump 3 and the steam separator 4 via a three-way valve 2, is provided for the cooling loop. And a level gauge 7 detecting the water level of cooling water is set in the steam separator 4. Signals from the level gauge 7 are set to a control means 9 via a signal line 10 so as to be operated, so that the resultant thereby controls the opening of the valve 8 as a open command via a signal line 11. By this constitution, supplemental water is mixed with a great amount of cooling water of the steam separator 4 as compared with a case that supplemental cooling water is fed to the inlet port of the pump 3, the fluctuation of the temperature of cooling water fed to a cell main body 5 through the pump 3 ends in small one.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a cooling device for a fuel cell.

[0002]

2. Description of the Related Art A large number of cells for power generation and a cooling plate for discharging heat generated in the cells are laminated on a fuel cell main body, and cooling water is externally supplied to and discharged from the cooling plate. It has a cooling loop consisting of a circulation pump and piping, and a steam separator for taking out steam for reforming. Further, this cooling loop is provided with a blow-down outlet for maintaining the quality of the cooling water. When such a device is operated, the amount of cooling water in the cooling loop decreases due to the removal of the reforming steam and blowdown.
Therefore, a cooling water supply pump and piping are provided between the circulation pump and the steam separator in the loop as shown in FIG. 7 to detect the position of the liquid surface of the cooling water in the steam separator. The pump for replenishing cooling water is operated to feed the replenishing cooling water.

[0003]

In this conventional cooling system, the makeup cooling water that has not been preheated to obtain the NPSH (pushing head) of the circulation pump is intermittently supplied before the inlet of the circulation pump. It has become. Therefore, the temperature of the cooling water entering the cooling plate fluctuates depending on the presence or absence of replenishment, causing thermal cycle fatigue inside the battery, causing deterioration of the battery material, movement of the electrolyte, and the like, which leads to deterioration and performance of the battery.

Therefore, an object of the present invention is to provide a cooling device which can replenish cooling water to a cooling loop without causing performance deterioration or destruction of the battery due to fluctuation of cooling water temperature entering a cooling plate.

[0005]

In order to achieve the above-mentioned object, the present invention aims to continuously supply the cooling water from the outside to the cooling loop or to supply it to a steam separator having a large heat capacity. It is a feature.

[0006]

By the above means, it is possible to prevent the temperature fluctuation of the cooling water supplied to the battery body from becoming small, and to prevent the deterioration of the performance of the battery and the destruction thereof.

[0007]

【Example】

(Embodiment 1) An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, a battery main body 5 has a large number of cells for power generation and a cooling plate for discharging heat generated in the cells stacked, and a circulation pump 3 for circulating and supplying cooling water to the cooling plates. A cooling loop is formed of a blowdown take-out pipe and valve 8 for maintaining the quality of the cooling water, and a steam separator 4 for taking out steam for the reformer. Further, in this cooling loop, cooling water replenishment pipes from the replenishment pump 1 for replenishing the cooling water from the outside to the inlets of the steam separator 4 and the circulation pump 3 via the three-way valve 2 are respectively provided. There is. The steam separator 4 is provided with a water level gauge 7 for detecting the water level of the cooling water therein. The signal of the water level gauge 7 is sent to the control device 9 via the signal line 10 and is calculated as an opening degree command to control the opening degree of the flow control valve 8 of the blowdown pipe via the signal line 11. ing.

Normally, the makeup cooling water is supplied to the steam separator 4 by the makeup pump 1 via the three-way valve 2. By doing so, compared with the case of supplying the supplemental cooling water to the inlet of the circulation pump 3, it is supplied to the battery main body 5 through the circulation pump 3 by being mixed with a large amount of cooling water of the steam separator 4. The temperature fluctuation of the cooling water is small as shown in FIG.

As described above, by keeping the temperature fluctuation of the cooling water sent to the battery main body small, it is possible to suppress the volume fluctuation of the electrolyte in the battery main body and prevent the overflow of the electrolyte. As shown, the deterioration of the battery performance can be reduced. Further, when the NPSH (push head) of the circulation pump 3 is insufficient due to the load fluctuation of the battery, it is necessary to set the valve opening degree of the three-way valve 2 in advance and directly supply it to the inlet of the circulation pump 3. It is also possible to obtain a high NPSH. (Example 2)

In FIG. 4, the replenishment pump 1 is directly connected to the steam separator 4 via a flow control valve 12. With respect to the other constituent elements, the elements having the same functions as those in FIG. In the case of this configuration, it goes without saying that the same effect can be expected even if the flow control valve 12 is an ON / OFF valve.

The controller 9 receives a signal from the water level gauge 7 of the steam / water separator 4, and the flow control valve 12 directly supplies cooling water to the steam / water separator 4 to keep the water level of the steam / water separator 4 constant. Maintained in the range of. Since the supplied cooling water is mixed in the steam separator 4 having a large heat capacity and then supplied to the battery main body 5, the temperature change of the cooling water is suppressed to a small level. In this way, the temperature change of the cooling water can be suppressed to a small level, and the deterioration of the battery performance can be reduced as shown in FIG. (Example 3)

In FIG. 5, makeup cooling water is directly supplied to the steam separator 4 via the three-way valve 2, but the heat exchanger 6 is installed in the pipe connecting the three-way valve 2 and the steam separator 4. ing. With respect to the other constituent elements, the elements having the same functions as those in FIG. In this case, the blowdown flow control valve may be an ON / OFF valve.

The controller 9 receives the signal from the water level gauge 7 of the steam / water separator 4 via the signal line 10 and controls the flow control valve 8 via the signal line 11 to directly connect to the steam / water separator 4. The flow rate of the replenished cooling water is controlled, and the water level of the steam separator 4 is maintained within a certain range.

The supplied cooling water is heated by the blowdown water at the temperature of the cooling loop through the heat exchanger, and then mixed in the steam separator 4 having a large heat capacity and supplied to the battery body 5. Therefore, the temperature change of the cooling water can be suppressed to be smaller than that in the first embodiment. (Example 4)

In FIG. 6, make-up cooling water is directly supplied to the steam separator 4 via the three-way valve 2, and the three-way valve 2 and the circulation pump 3 are connected via the heat exchanger 6. Regarding other components, the same numbers are given to the components having the same functions as in FIG.

The controller 9 receives the signal from the water level gauge 7 of the steam / water separator 4 via the signal line 10 and controls the flow control valve 8 via the signal line 11 to control the water level of the steam / water separator 4. Is maintained within a certain range. The cooling water supplied directly to the steam separator 4 is mixed in the steam separator 4 having a large heat capacity and then supplied to the battery body 5.

On the other hand, the cooling water directly supplied to the circulation pump 3 is heated by the blowdown water at the temperature of the cooling loop via the heat exchanger and then supplied to the battery main body 5 via the circulation pump 3. Therefore, the temperature change of the cooling water can be suppressed small.

[0019]

As described above, according to the present invention, in the cooling loop including the cooling plate, the circulation pump and the steam separator, the cooling water is supplied to the steam separator from the outside. Since this is done, the temperature fluctuation of the cooling water entering the cooling plate can be reduced, and the cooling water can be replenished to the cooling loop without degrading the performance of the battery or destroying it.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a main embodiment according to the present invention.

FIG. 2 is a graph showing temperature fluctuations of cooling water entering a cooling plate according to the related art and the present invention.

FIG. 3 is a diagram showing a state of performance deterioration of a battery according to the related art and the present invention.

FIG. 4 is a diagram showing another embodiment.

FIG. 5 is a diagram showing another embodiment.

FIG. 6 is a diagram showing another embodiment.

FIG. 7 is a configuration diagram showing a conventional example.

[Explanation of symbols]

1 ... Cooling water supply pump, 2 ... Three-way valve, 3 ... Cooling water circulation pump, 4 ... Steam separator, 5 ... Battery body, 6 ... Heat exchanger, 7 ... Water level gauge, 8 ... Flow control valve, 9 …Control device.

Claims (5)

[Claims] 1. A cooling loop having a circulation pump for supplying cooling water to a fuel cell main body, a pipe and a steam separator, and continuously supplying cooling water from the outside to the cooling loop. A cooling device for a fuel cell, which is provided with a replenishing device. 2. The fuel according to claim 1, wherein the blowdown water amount is controlled by the water level signal of the steam-water separator in the cooling loop, and the water level of the steam-water separator is always maintained within a certain range. Battery cooling device. 3. The cooling device for a fuel cell according to claim 1, wherein the cooling water is directly supplied to the steam separator. 4. The cooling device for a fuel cell according to claim 3, wherein the supply pump is intermittently operated by the water level of the steam separator when the steam separator is directly supplied. 5. The cooling device for the fuel cell according to claim 1, wherein a blow-down from the cooling loop is used to install a heat exchanger in the cooling water supply pipe to preheat the supplied cooling water. .