JP2606335Y2 - Redox flow battery cell - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention generally relates to a cell of a redox flow battery, and more specifically, to reducing the number of parts and improving the reliability of a liquid seal. To a redox flow battery cell improved to

[0002]

2. Description of the Related Art In order to supply stable power to customers, a power company needs to generate power in accordance with the demand for power. For this reason, electric power companies are constantly constructing power generation facilities that meet the maximum demand and generating electricity in response to the demand. However, as shown by the power demand curve A in FIG. 8, there is a large difference in power demand between daytime and nighttime. Similar phenomena occur during the week, month and season.

Therefore, if it is possible to efficiently store electric power, surplus electric power (corresponding to the portion indicated by the symbol X in FIG. 8) is stored at off-peak time, and released at peak time. 7 can be covered. In this way, it is possible to cope with fluctuations in demand, and the electric power company only needs to always generate substantially constant electric power (an amount corresponding to the broken line Z in FIG. 8). If such load leveling can be achieved, it is possible to reduce the number of power generation facilities, and to greatly contribute to saving energy and saving fuel such as oil.

Therefore, various power storage methods have been conventionally proposed. For example, pumped storage power generation has already been implemented, but in pumped storage power generation, facilities are installed far away from the consuming area. Therefore, this method has problems such as transmission and transformation losses and restrictions on environmental location. Therefore, development of a new power storage technology that replaces pumped storage power generation is desired, and as one of them, the development of a redox flow battery is being promoted.

FIG. 9 is a schematic diagram showing an example of a redox flow battery that has been already proposed. Referring to FIG. 9, an electrolytic layer 20 partitioned by a diaphragm (for example, a cation exchange membrane) 10 is provided with a positive electrode chamber 22 having a positive electrode 12 and a negative electrode chamber 21 having a negative electrode 11. Positive electrolyte stored in the tank 23a is continuously supplied to the positive electrode chamber 22 by the pump 24a. Similarly, the negative electrolytic solution stored in the tank 23b is continuously supplied to the negative electrode chamber 21 by the pump 24b. As a positive electrolyte,
For example, when an aqueous solution containing iron ions and an aqueous solution containing chromium ions as the negative electrolyte are used, reduction of Fe ^{3 +} to Fe ^{2 +} (positive electrode) and oxidation of Cr ^{2 +} to Cr ^{3 +} (negative electrode) Discharge is performed, and charging is performed by the reverse reaction. At this time, hydrogen ions pass through the diaphragm 10 provided between the two electrodes. The battery reactions occurring at both electrodes are as follows.

[0006]

Embedded image

A redox flow battery operating according to the above principle has, for example, a structure in which a plurality of cells shown in FIG. 10 are stacked. As shown in the figure, in the cell 1, the components of the bipolar plate 13, the negative electrode 11, the diaphragm 10, the positive electrode 12, and the bipolar plate 14 are sequentially arranged. Bipolar plates 13 and 1
Frames 15a and 15b are fixedly provided on the outer peripheral portion of the frame 4, respectively. A gasket 16a is interposed between the frame 15a and the diaphragm 10, and a gasket 16b is interposed between the diaphragm 10 and the frame 15b. The positive electrode 12 is arranged between the diaphragm 10 and the bipolar plate 14 so as to be sandwiched. Similarly, the negative electrode 11
It is arranged between the bipolar plate 13 and the diaphragm 10 in a sandwiched state. Frames 15a, 15b, gasket 16
Manifolds 27 serving as passages for supplying an electrolytic solution to the inside of the cell are formed in a, 16b and diaphragm 10. After these components are stacked, the bipolar plate 1
3. The negative electrolyte formed by the negative electrode 11 and the diaphragm 10 is filled with a negative electrolyte, and the positive electrode formed by the bipolar plate 14, the positive electrode 12 and the diaphragm 10 is filled with the positive electrolyte. When filling the electrolyte, gaskets 16a and 16b
Are tightly attached to the diaphragm and the frame, respectively, so as not to leak the electrolyte solution to the outside when tightened. Conventionally, the gaskets 16a and 16b are often of a flat plate shape.

The cells 1 configured as described above are stacked in large numbers to form a cell stack as shown in FIG.
In the cell stack 30, a large number of cells 1 are stacked and 1
The bolt 18 is sandwiched between the pair of end plates 17a and 17b.
Has been tightened by. On the side surface of the cell stack 30, an electrolyte supply plate 19c having an electrolyte inlet 19a and an electrolyte outlet 19b is provided. An appropriate number of such cell stacks are used for power storage.

[0009]

FIG. 12 is a detailed view of the cells of the redox flow battery shown in FIG. FIG.
, Gaskets 16a and 16b are connected to bipolar plate 1
This is to prevent the electrolyte solution from leaking while maintaining the distance between the diaphragms 3 and 14 and the diaphragm 10. The gaskets 16a and 16b are tightened in consideration of the occurrence of loosening and creep due to temperature change. Such tightening is performed by the bolts as described above. However, it is difficult for the conventional flat gaskets 16a and 16b to uniformly tighten the entire gaskets 16a and 16b using a considerable number of bolts. In addition, there is a possibility that the electrolyte may leak. Further, in order to ensure the sealing performance, it is necessary to perform the tightening with a very strong force. The pressure must be maintained until the gasket is deformed by several% to several tens%. On the other hand, if the gasket is strongly tightened in an uneven manner, the bipolar plates 13, 14 and the like are distorted. The plates 13 and 14 may be damaged.

The conventional cell also has the following problems.

That is, referring to FIG.
Numerals 5a and 15b are made of vinyl chloride, and two vinyl chloride flat plates are adhered with an adhesive for vinyl chloride. Also, grooves are formed in the frames 15a and 15b,
The bipolar plates 13 and 14 were sandwiched, and these were bonded with an epoxy resin adhesive.

Accordingly, there is a problem that the adhesive portion is peeled off due to a difference in the thermal expansion coefficient between the two, and there is a problem such as peeling of the interface, and the reliability of the liquid seal is poor. Also, the bonding operation was troublesome. Further, since the gaskets 16a and 16b are required, there is a problem that the number of parts is large.

It is therefore an object of the present invention to provide a cell of a redox flow battery which has a high reliability in liquid sealing and is improved so that the number of parts is reduced.

[0014]

The redox flow battery according to the present invention comprises a diaphragm, a pair of bipolar plates disposed on both sides of the diaphragm, and a pair of the bipolar plate and the bipolar plate. And an electrode disposed therebetween. A first frame and a second frame are provided fixedly on the outer peripheral portion of each of the pair of bipolar plates, with the peripheral surfaces of the diaphragm being sandwiched therebetween, with their contact surfaces being in close contact with each other. An electrode chamber for housing the electrode is formed between the diaphragm and the bipolar plate. A through-hole for flowing an electrolytic solution to be supplied to the electrode chamber is provided so as to penetrate the first and second frames. The through-hole and the electrode chamber are connected to a thickness portion of the first or second frame located between the bipolar plate and the diaphragm, and an electrolytic solution sent through the through-hole is passed through. A liquid feed passage for feeding to the electrode chamber is provided internally. First sealing means for sealing an electrolytic solution is provided on each of the close contact surfaces of the first and second frames so as to surround the bipolar plate. On the contact surface of the first or second frame, a second seal means for sealing an electrolyte is provided in an annular shape so as to surround the through hole independently of the first seal means. ing. The first and second frames
The memory is made of vinyl chloride resin.

According to a preferred embodiment of the present invention, the sealing means includes a protrusion provided on the contact surface.

Further, the sealing means includes an annular groove provided on the contact surface of the frame, and an O-ring fitted into the groove.

[0017]

According to the redox flow battery cell of the present invention, the first frame and the second frame fixedly provided on the respective outer peripheral portions of the pair of bipolar plates sandwich the peripheral edge of the diaphragm. In this state, the contact surfaces are brought into close contact with each other, so that the diaphragm can be firmly fixed and liquid leakage can be strongly prevented. In addition, the first sealing means for sealing the electrolyte is provided on each of the contact surfaces of the first and second frames so as to surround the bipolar plate. Becomes unnecessary. In addition, a second sealing means for sealing the electrolytic solution is provided on the contact surface of the first or second frame independently of the first sealing means in an annular manner so as to surround the through hole. Therefore, the sealing means is double-formed, and the sealing ability is improved. Ma
The first and second frames are made of vinyl chloride resin.
Therefore, the first and second sealing means
And strengthen the contact surfaces of the first and second frames.
Even if it is tightly adhered, due to the hardness of vinyl chloride resin,
Is not occluded.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a perspective view of a cell of a redox flow battery according to an embodiment of the present invention. FIG. 2 shows FIG.
3 is a cross-sectional view along the line II-II, and FIG. 3 is a cross-sectional view along the line III-III in FIG.

Referring to these drawings, the redox flow battery includes a diaphragm 10. A pair of bipolar plates 13 and 14 are arranged on both sides with the diaphragm 10 interposed therebetween. A negative electrode 11 is arranged between the diaphragm 10 and the bipolar plate 13, and a positive electrode 12 is arranged between the diaphragm 10 and the bipolar plate 14. A rubber frame 15 is provided on the outer peripheral portion of the bipolar plate 13.
a, and a rubber frame 15 b is provided on the outer peripheral portion of the bipolar plate 14. The bipolar plate 13 is the frame 1
5a and is fixed. Similarly, bipolar plate 14 is sandwiched and fixed between frames 15b.
In the cell according to the embodiment, the bipolar plates 13 and 14 and the frames 15a and 15b are not bonded with an adhesive. Therefore, the bipolar plates 13 and 14 and the frame 15
Even if there is a difference in the coefficient of thermal expansion between a and 15b, mutual displacement occurs, so that no thermal stress is generated, and as a result, cracks and breakage of the bipolar plates 13 and 14 are eliminated. Further, there is an advantage that the bonding operation is not required and the number of assembling steps is reduced.

The frame 15a and the frame 15b are
They are in close contact with each other with a 0 therebetween. Sealing means 5 for sealing the electrolyte is provided on the contact surfaces of the frames 15a and 15b so as to surround the bipolar plate 14.
2 are provided. The sealing means 52 is constituted by a mountain-shaped projection. The mountain-shaped projection is the frame 1
5a and 15b are formed integrally. Frame 15
a and a projection (52) formed on the contact surface of
The protrusions (52) formed on the contact surface of the frame 5b are formed so as to be shifted from each other when the contact surface of the frame 15a and the contact surface of the frame 15b are brought into close contact with each other.

Each of the frames 15a and 15b has
A through hole 51 for passing the electrolyte is provided. The through holes 51 are provided on the contact surfaces of the frames 15a and 15b.
Ring-shaped sealing projections 5 surrounding the
3 are provided. In the cell according to the embodiment, the frame 15a and the frame 15b are brought into close contact with the diaphragm 10 interposed therebetween by tightening. In this close contact
Protrusions 5 formed on the contact surfaces of frames 15a and 15b
2 and 53 are assigned to the corresponding frames 15a and 15b. Then, the projections 52 and 53 are tightened.
So that the frames 15a and 15b
Are adhered with the diaphragm 10 interposed therebetween. Projection 52,
Since 53 is very small, its deformation does not require a large force as compared with the related art. In addition, the deformation can be uniformly caused over the entire protrusion by a relatively small force. Therefore, even if the tightening is weak, the protrusion 5
2 and 53 can be brought into close contact with each other, and the sealing property can be reliably maintained. In FIGS. 2 and 3, the arrows indicate the direction in which the electrolyte flows.

In the above embodiment, the frames 15a, 15a,
Although the case where 15b is formed of rubber is illustrated, the present invention is not limited to this, and these may be formed of vinyl chloride.

FIG. 4 shows another embodiment of the present invention.
It is a perspective view of the cell of a redox flow battery. FIG.
FIG. 5 is a sectional view taken along line VV in FIG. 3. FIG. 5 is a sectional view taken along the line VI-VI in FIG. In addition,
The embodiment shown in FIGS. 4, 5, and 6 is the same as the embodiment shown in FIGS. 1, 2, and 3 except for the following points. Is not repeated. FIG.
1 differs from the embodiment shown in FIG. 1 in that a combination of a groove and an O-ring fitted into the groove is used as the sealing means. Referring to FIGS. 4, 5 and 6, the sealing means 52 is provided on the contact surfaces of the frames 15a and 15b.
A groove 521 is formed annularly so as to surround the bipolar plates 13 and 14, and an O-ring 520 is fitted into the groove 521. Another difference is that a groove 531 is formed annularly on the contact surfaces of the frames 15a and 15b so as to surround the through hole 51, and an O-ring 530 is fitted into the groove 531.

In this embodiment, the frames 15a and 15b provided on the outer peripheral portions of the bipolar plates 13 and 14 by tightening are brought into close contact with the diaphragm 10 interposed therebetween. In this close contact, the grooves 5 of the frames 15a and 15b
O-rings 520, 530 fitted into 21,531
However, the opposite frames 15a,
15b. Next, the O-rings 520 and 530 are brought into close contact with the frames 15a and 15b such that the O-rings 520 and 530 are crushed by tightening. O-ring 52
Since 0,530 is very small, its deformation does not require a large force as compared with the related art. In addition, the entire O-rings 520 and 530 can be uniformly deformed by a relatively small force. Therefore, even if the tightening is weak, the O-rings 520 and 530 can be easily brought into close contact with each other, and the sealing property can be reliably maintained.

The method using the O-ring has the following advantages. Referring to FIG. 7A, the interval between the tightening allowances 60 is determined by the sizes of the O-rings 520 and 530. Referring to FIG. 7B (FIG. 7B shows a tightened state), O-rings 520 and 530 are shown.
According to this method, the surface spacing between the bipolar plate 13 and the bipolar plate 14, which affects the performance of the battery, can be strictly maintained at a predetermined size.

[0027]

As described above, according to the redox flow battery cell of the present invention, the first frame and the second frame fixedly provided on the respective outer peripheral portions of the pair of bipolar plates are provided. Since the contact surfaces of the diaphragms are in close contact with each other while sandwiching the peripheral edge of the diaphragm, the diaphragms can be firmly fixed and liquid leakage can be strongly prevented. In addition, since the first and second frames are provided with first sealing means for sealing the electrolyte, the first sealing means is provided on the respective contact surfaces of the first and second frames so as to surround the bipolar plate. No gasket is required. As a result, the number of parts is reduced and the number of assembling steps is reduced, so that the production cost of the cells of the redox flow battery can be reduced. In addition, a second sealing means for sealing the electrolytic solution is provided on the contact surface of the first or second frame independently of the first sealing means in an annular manner so as to surround the through hole. As a result, the sealing means is double-formed, and the effect of improving the ability to seal the electrolyte is exhibited.
The first and second frames are made of vinyl chloride resin.
Therefore, the first and second sealing means are interposed.
And tightly contact the contact surfaces of the first and second frames.
Even if it is made, the liquid supply path is blocked due to the rigidity of the vinyl chloride resin.
Not done. As a result, while preventing liquid leakage strongly,
The liquid can be circulated smoothly.

[Brief description of the drawings]

FIG. 1 is a perspective view of a cell of a redox flow battery according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along the line II-II in FIG.

FIG. 3 is a sectional view taken along line III-III in FIG.

FIG. 4 is a perspective view of a cell of a redox flow battery according to another embodiment of the present invention.

FIG. 5 is a sectional view taken along line VV in FIG. 4;

FIG. 6 is a sectional view taken along the line VI-VI in FIG. 4;

FIG. 7 is a diagram for explaining an advantage when an O-ring is used as a sealing means.

FIG. 8 is a diagram showing a power demand curve.

FIG. 9 is a schematic diagram showing a system configuration of a redox flow battery.

FIG. 10 is a perspective view showing cells of a conventional stacked binary battery.

FIG. 11 is a perspective view showing a cell stack of a redox flow battery.

FIG. 12 is a detailed view of a cell of a conventional redox flow battery.

[Explanation of symbols]

 Reference Signs List 10 diaphragm 11 negative electrode 12 positive electrode 13 bipolar plate 14 bipolar plate 15a frame 15b frame 52 sealing means

Claims (3)

(57) [Scope of request for utility model registration] A diaphragm, a pair of bipolar plates disposed on both sides of the diaphragm, an electrode disposed between the diaphragm and the bipolar plate, and a pair of bipolar plates. A first frame and a second frame, which are fixedly provided on the respective outer peripheral portions and sandwich their contact surfaces with each other while sandwiching the periphery of the diaphragm, between the diaphragm and the bipolar plate; An electrode chamber formed and accommodating the electrode; a through hole provided to penetrate the first and second frames, for flowing an electrolytic solution to be supplied to the electrode chamber; Of the frame, which is provided in a thickness portion located between the bipolar plate and the diaphragm, connects the through hole to the electrode chamber, and supplies the electrolytic solution sent through the through hole to the electrode chamber. A liquid supply path to be sent to each of the first and second frames A first seal means provided in an annular shape on the contact surface to surround the bipolar plate to seal an electrolyte; and a first seal on the contact surface of the first or second frame. And a second sealing means for sealing the electrolytic solution, which is annularly provided so as to surround the through hole, independently of the means , wherein the first and second frames are formed of a vinyl chloride resin. Sa
It is to have the cell of the redox flow battery. 2. The redox flow according to claim 1, wherein said first sealing means is formed by a projection integrally formed on each of said contact surfaces of said first and second frames. Battery cell. 3. A projection formed on the contact surface of the first frame and a projection formed on the contact surface of the second frame, the projection formed on the contact surface of the first frame and the projection formed on the second frame. The cell of the redox flow battery according to claim 2, wherein the cells are formed so as to be shifted from each other when the contact surfaces of the frame are brought into close contact with each other.