JPH04155771A - Fuel cell power generator - Google Patents

Abstract

PURPOSE:To obtain a device for securing a stable electric power supply by installing strain gauges on rods, and arranging a strain measuring apparatus to compare data outputted from the strain gauges in respective cell bodies outside of the cell bodies. CONSTITUTION:Strain gauges 29 arranged on respective rods 26 detect fastening force of the rods 26, and strain gauge wires 30 input these detected signals to a strain measuring apparatus 32 on the outside of the device. The measuring apparatus 32 gathers respective output data from cell bodies N1, N2 and N3, and displays graphically the fastening force of the rods 26, that is, stress of a cell stack 9. In the case when the stress in the cell body N3 drops rapidly as shown by D in the drawing, by comparing it with the data from the cell bodies N1 and N2, a stress change can be found out immediately, so that by taking a proper safety measure such as stopping of the cell body N3, the occurrence of abnormality in the cell bodies can be amended at its early stage.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a fuel cell power generation device, and particularly to internal abnormality diagnosis of a battery main body.

(Prior Art) In recent years, fuel cell power generation devices have attracted much attention. This fuel cell power generation device oxidizes the chemical energy of fuel through an electrochemical process, and directly converts the energy released by this oxidation reaction into electrical energy.

This fuel cell power generation device emits very little SOX and NOx, and also produces low vibration noise. Furthermore, since the power generation device does not include a fuel cycle, it does not require large amounts of cooling water. Therefore, fuel cell power generation equipment can in principle ensure high conversion efficiency, and even on a relatively small scale, the power generation efficiency reaches 40-50%, an extremely high value that surpasses the latest thermal power generation. It is possible to obtain. Moreover, it exhibits excellent responsiveness to load fluctuations, and also has low noise due to vibration noise and low levels of SOX and NOx exhaust gases that cause pollution, so it has little impact on environmental problems that are becoming a social issue.

There is a great demand for fuel cell power generation devices that have the above-mentioned advantages, and there are expectations and interest in the research results for their development and practical application. For example, as a conventional example of this type of device, the one described in Japanese Patent Application Laid-Open No. 60-83765 is known.

Here, the principle of the fuel cell that constitutes the fuel cell power generation device will be explained. That is, as shown in FIG. 4, an electrolyte layer 2 impregnated with an electrolytic solution such as phosphoric acid is interposed between a pair of opposing porous electrodes 1 to form a unit cell. When hydrogen gas H and air A, which are fuel gases, are continuously supplied to both end faces of this unit cell, reaction products and reaction residues are continuously removed to the outside, so power generation continues for a long period of time. will be continued.

Further, the basic configuration of the above fuel cell is as shown in FIG. That is, on both sides of the electrolyte matrix layer 3,
A positive electrode 4 and a negative electrode 5 are arranged to form a rectangular plate-shaped unit cell. Furthermore, in order to use these single cells as power generating batteries, a large number of single cells are connected in series and stacked.

Interconnectors 6 are disposed in gaps between these stacked unit cells, and are alternately stacked with the unit cells. The upper and lower surfaces of this interconnector 6 are provided with a plurality of grooves that open at two opposing edges so as to supply gas to the unit cells. The groove on the bottom side is an air flow path 8 through which air A flows.
becomes.

At this time, the hydrogen gas flow path 7 and the air flow path 8 are arranged in directions perpendicular to each other.

By the way, in the fuel cell N currently under development, as shown in FIGS. 6 and 7, a cell stack 9 is constructed by stacking a plurality of the above-mentioned unit cells in the shape of a rectangular column, and the four circumferential sides of the cell stack 9 are A manifold 10 for supplying reaction gas is attached to the reactor. A hydrogen gas supply pipe 11, a hydrogen gas discharge pipe 12, an air supply pipe 13, and an air discharge pipe 14 are connected to this manifold 10, respectively, and the hydrogen gas H flows inside the cell stack 9 in the direction of arrow a, while the air A is cell stack 9
It is designed to flow in the direction of the arrow.

Further, although it is preferable for the operating temperature of the cell stack 9 to be high in terms of reaction theory, it is desired to maintain the operating temperature at around 200° C. due to constraints such as the heat resistance of the constituent materials and the vapor pressure of the electrolyte.

Therefore, in the above conventional example, as shown in FIG. 6, a conduit consisting of a cooling water supply pipe 15 and a cooling water discharge pipe 16 is buried in the cell stack 9. By circulating the cooling water flowing through this conduit within the cell stack 9 as shown by the broken line C, heating at the time of starting the fuel cell and heat generated during operation are reduced, and the cell stack 9 is heated to an appropriate temperature. It is supposed to be cooled.

Further, the components of the fuel cell described above are housed in a tank 21, and a manifold 1 is installed in this tank 21.
Nitrogen gas or the like is sealed in order to suppress leakage of 0 and other reactive gases. Furthermore, the output of the fuel cell is direct current, and the power terminal (positive electrode) 1 disposed at the upper and lower ends of the cell stack 9
7 and a power terminal (negative electrode) 18 , and is led out of the tank 21 via a connecting conductor 19 and a bushing 20 .

By the way, in the fuel cells shown in FIGS. 6 and 7,
The unit capacity is proportional to the unit cell area and the number of stacked units.

However, since the porous electrode plate constituting the unit cell is made of a brittle material, it is difficult to mold it to a uniform thickness over the entire surface, and there are significant restrictions on the lamination work, and it is difficult to obtain a uniform tightening force over the entire surface. Therefore, it is extremely difficult to significantly increase the area of a single cell. On the other hand, there is a limit to the number of single cells that can be stacked due to restrictions on transportation or stacking operations. Therefore, the capacity of each cell stack 9 is usually 500 to 1000.
It is suppressed to kv. Therefore, when a large-capacity fuel cell power generation device is put into practical use, a plurality of battery bodies N1, N2, and N3 are arranged in parallel as shown in FIG.

Further, the fuel cell configured in this manner needs to maintain an appropriate tightening force to the cell stack 9 in order to maintain output. Here, the appropriate tightening force refers to a force that does not damage the low-strength unit cells and allows the unit cells and the interconnector to be completely brought into close contact with each other. By tightening the cell stack 9 with such an appropriate force, it is possible to prevent damage to the cells, reduce the electrical resistance between the cells, and prevent mixing of reaction gases flowing in orthogonal directions. .

As a result, the fuel cell can output stable electrical energy.

Taking the fuel cells shown in FIGS. 6 and 7 as an example, a current collector plate 22 and an insulating plate 2 are provided at the top and bottom of the cell stack 9, respectively.
A tightening plate 24 is disposed via 3. This tightening plate 2
Cross-shaped support fittings 25 are attached to the top and bottom of 4. At this time, evenly tighten the flat surface of the cell stack 9,
Furthermore, the thickness of the clamping plate 24 is set to be sufficiently thick to prevent deformation. Furthermore, since the support fittings 25 are disposed outside the clamping plate 24, they also serve to reinforce the clamping plate 24. Further, a rod 26 is inserted through the tip of each of the four arms of the support fitting 25.
It is fixed by a nut 28 formed at the end of 6. The tightening member consisting of the rod 26 and the nut 28 is made of steel, and the unit cells constituted by the cell stack 9 are fastened from above and below by this tightening member. In addition, since the tightening force is relatively large between the nut 28 on the upper end side of the rod 26 and the supporting metal fitting 25, a countersunk 2 is installed so that a large load can be obtained in a small space.
7 is installed.

By the way, with the cell stack 9 and the steel fastening member,
The coefficient of thermal expansion of both is approximately 2×10 −5 or more, and a difference in temperature rise occurs. For example, when the height of the stacked cell stacks 9 is 3 m and the temperature is 200° C., the cell stacks 9 expand more than the tightening member by several tens of mm.

On the other hand, if stacked unit cells are tightened for a long period of time, the dimension in the thickness direction tends to decrease due to so-called break-in.

As described above, since the cell stack 9 expands and contracts in the vertical direction due to heat and pressure, it is extremely difficult to maintain a constant optimal tightening force on the cell stack 9. This impairs the stability of the power supply, which has become a problem. Therefore, in order to maintain a more appropriate tightening force than before,
Various ideas have been made, one example of which is the disc spring 27 shown in FIGS. 6 and 7. Here, the disc spring 27 functions to absorb the difference in stack expansion due to thermal fluctuations from startup to operation of the device.

(Problems to be Solved by the Invention) However, the following problems have been pointed out in the prior art.

In other words, even though various efforts have been made to maintain an appropriate tightening force on the cell stack, it is difficult to determine from outside the tank whether the cell stack is being held with the optimum tightening force. I couldn't. Therefore, even if the tightening force to the cell stack suddenly weakens while the device is in operation, the decrease in tightening force cannot be detected until the loss of output energy due to the increase in the resistance value between cells becomes significant. was difficult. Therefore, there was a risk that the cells and the interconnector would not be in close contact with each other, and the seal between the cells would be incomplete, causing the reaction gases to mix and cause a combustion phenomenon. On the other hand, when the tightening force of the cell stack becomes too strong, the possibility of damage to the single cells increases. Therefore, in order to ensure the safety of the device, a great deal of effort is spent on monitoring the tightening force on the cell stack, and it is necessary to periodically stop the device and diagnose internal abnormalities in the battery body. There was sex.

Furthermore, when a plurality of battery bodies are arranged in parallel to realize a large-capacity power generation device, if an abnormality occurs in even one battery body, the entire device may be affected. Moreover,
It was difficult to quickly find a malfunctioning battery among multiple battery bodies, and the operating efficiency of the device was low. Therefore, if the number of battery bodies installed increases,
Monitoring work also became troublesome, which hindered the ability to increase the capacity of power generation equipment.

The present invention has been made in consideration of the above points, and its purpose is to detect the tightening force of the cell stack with a simple configuration, accurately monitor abnormalities in the battery body, and Our objective is to provide an excellent fuel cell power generation device that ensures a stable supply of electricity.

[Structure of the Invention (Means for Solving the Problems) To achieve the above object, the present invention comprises stacking a plurality of rectangular planar unit cells in a square column shape with an electrolyte layer interposed between a pair of electrodes. This is fastened to the upper and lower clamping plates to form a cell stack, supporting metal fittings are arranged above and below the cell stack, and the cell stack has rods and nuts for tightening these supporting metal fittings, and is stored in the tank. A fuel cell power generation device consisting of a battery body consisting of a battery body, characterized in that a strain gauge is attached to the rod, and a strain measuring device for comparing data output from the strain gauges of each battery body is installed outside the battery body. It is.

(Function) The function of the present invention having the above configuration is as follows.

That is, a strain gauge attached to the rod detects the tightening force of the rod, which is the stress of the cell stack, and sends this data to a strain measuring device provided outside the device. The strain measuring device then compares and examines the data output from the battery itself to comprehensively determine the stress in the cell stack.

As described above, according to the present invention, the tightening state of the cell stack of the battery main body can be constantly monitored from outside the device. Therefore, abnormalities in the cell stack can be detected early and appropriate safety measures can be taken, contributing to improved operation of the entire fuel cell power generation system.

(Example) An example of the present invention will be specifically described based on FIGS. 1 to 3. Note that the same members as those in the conventional example shown in FIGS. 4 to 8 are designated by the same reference numerals, and explanations thereof will be omitted.

That is, as shown in FIG. 1, in the battery body N, a strain gauge 29 is attached near the upper end of the rod 26. This strain gauge 29 detects the tightening force of the rod 26 and outputs the detection signal as data, and a strain gauge wire 30 for data output is installed. On the other hand, a strain gauge penetrating portion 31 is opened in the tank 21 . This strain gauge penetrating portion 31 has the strain cage wire 3
0 is inserted. Also, strain gauge wire 30
The tip of the tank 21 is connected to a strain measuring device 32 provided outside the tank 21.

The strain measuring device 32 is designed to compare and examine the detection data from each rod 26 of the battery body N.

Furthermore, as shown in FIG. 2, three battery bodies N1, N2, and N3 are installed in the fuel cell power generation apparatus of this embodiment. Strain gauges 29 are attached to the rods 26 of these battery bodies N1, N2, and N3, and strain gauge wires 3 extending from each strain gauge 29
0 are all connected to the strain measuring device 32.

The operation of this embodiment having the above configuration is as follows.

That is, the strain gauge 29 installed on each rod 26
detects the tightening force of the rod 26, and the strain gauge wire 30 sends this detection signal to the strain measuring device 3 outside the device.
Enter 2. In this way, the strain measuring device 32 collects each output data from the battery bodies N1, N2, and N3,
The tightening force of the rod 26, that is, the stress of the cell stack 9, is displayed in a graph as shown in FIG. Therefore, as shown in D in FIG. 3, when the stress in the battery body N3 decreases rapidly, the change in stress can be immediately discovered by comparing data from the battery bodies N1 and N2. Then, by taking appropriate security measures such as stopping the battery body N3,
Abnormalities in the battery body can be corrected at an early stage.

As described above, according to this embodiment, even if a plurality of battery bodies are provided, the detection data from each strain gauge 29 can be concentrated in one strain measuring device 32, thereby making it possible to make a comprehensive judgment. can. Moreover, since only the battery body in which an abnormality has occurred can be accurately detected, there is no problem even if a large number of battery bodies are arranged in parallel, and the capacity of the device can be increased.

Furthermore, since the strain measuring device 32 is installed outside the device, the battery body can be easily monitored at all times. As a result, it is possible to quickly respond to internal abnormalities in the battery body, and the safety and reliability of the device are greatly improved.

Note that the fuel cell power generation device of the present invention is not limited to the above embodiments, and as long as the tightening force of the rods can be detected, the strain gauges can be installed on multiple rods of the battery body in any way. Furthermore, the number of rods on which strain gauges are installed or the number of strain gauges installed on rods can be selected as appropriate.

[Effects of the Invention] As described above, according to the present invention, with a simple configuration in which a strain gauge is attached to the rod of the battery body and the output data from the strain gauge is compared and examined using a strain measuring device, Since constant monitoring can be performed from the outside of the device, it is possible to provide an excellent fuel cell power generation device that achieves excellent safety and reliability, facilitates monitoring work, and ensures a stable supply of electric power. can.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing an embodiment of the present invention, FIG. 2 is a configuration diagram showing this embodiment, and FIG. 3 is a cell stack of battery bodies N1 and N2N3 including an example of abnormality detection according to this embodiment. Figure 4 is a cross-sectional model diagram showing the principle of a fuel cell, Figure 5 is a perspective view showing the basic structure of a fuel cell, and Figures 6 and 7 are currently under development. FIG. 8 is a configuration diagram showing an example of a fuel cell power generation device composed of a plurality of battery bodies. DESCRIPTION OF SYMBOLS 1... Porous electrode, 2... Electrolyte layer, 3... Electrolyte matrix layer, 4... Positive electrode, 5... Negative electrode, 6...
... Grooved interconnector, 7... Hydrogen gas flow path,
8...Air flow path, 9...Cell stack, 10...
Manifold, 11...Hydrogen gas supply pipe, 12...
Hydrogen gas discharge pipe, 13... Air supply pipe, 14... Air discharge pipe, 15... Cooling water supply pipe, 16... Cooling water discharge pipe, 17... Power terminal (positive electrode), 18 ... Power terminal (negative electrode), 19... Connection conductor, 20... Bushing, 21... Tank, 22... Current collector plate, 23...
・Insulating plate, 24... Tightening plate, 25... Supporting metal fittings, 2
6... Rod, 27... Belleville spring, 28... Nut, 29... Strain gauge, 30... Strain gauge wire, 31... Strain gauge wire, 3
2...Strain measuring device.

Claims (1)

[Claims] A cell stack is formed by stacking a plurality of rectangular planar unit cells in a square column shape with an electrolyte layer interposed between a pair of electrodes, and fastening this to upper and lower clamping plates. In a fuel cell power generation device comprising support fittings arranged above and below the cell stack, rods and nuts for tightening these support fittings, and a battery body housed in a tank, a strain gauge is attached to the rod. A fuel cell power generation device characterized in that a strain measuring device for comparing data output from strain gauges of each battery body is installed outside the battery body.