JP2001043885A - Electrolyte tank, method of manufacturing the same, and method of attaching piping to electrolyte tank - Google Patents

Abstract

(57) [Problem] It is a main object to provide an electrolyte solution tank which is easy to install in terms of loading and assembly, and is improved so that oxygen does not enter from the outside. SOLUTION: The present invention relates to an electrolyte tank for storing an electrolyte circulated and circulated through an electrode. The electrolyte tank is plastic 2
A sheet obtained by laminating 1, 23 and the metal 22 is processed into a bag shape.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates generally to an electrolytic solution tank, and more particularly to an electrolytic solution tank used for an electrolyte flowing type battery such as a redox flow battery and a method for producing the same. The invention further provides
The present invention relates to a method for attaching a pipe to such an electrolyte tank.

[0002]

2. Description of the Related Art Japan's power demand has been increasing year by year. However, fluctuations in power demand tend to be remarkable year after year, reflecting the sophistication of the industrial structure and the improvement of the standard of living of the people. It is in. For example, assuming that the power demand in the daytime in summer is 100, that at dawn is 30 or less. On the other hand, when viewed from a power supply source, the ratio of nuclear power generation or large-scale thermal power generation, which does not desirably fluctuate in output, also tends to increase, and thus the necessity for power storage equipment is increasing.

[0003] At present, power storage is performed by pumped-storage power generation, but due to its limited location, it is said that new power storage technologies, especially technically and economically, are highly feasible. Secondary batteries for power storage are being actively researched. Among them, a redox flow type battery has attracted particular attention.

FIG. 4 is a schematic diagram of an all-vanadium redox flow battery disclosed in Japanese Patent Publication No. 2724817.

[0005] Referring to FIG. 4, an all-vanadium redox flow battery 1 includes a battery reaction cell 2, a negative electrode solution tank 3 and a positive electrode solution tank 4. The inside of the battery reaction cell 2 is partitioned by a diaphragm 5 made of, for example, an ion exchange membrane, and one side is a negative electrode cell 2a and the other side is a positive electrode cell 2b.
Is configured.

The positive electrode cell 2b accommodates a positive electrode as an electrode, and the negative electrode cell 2a accommodates a negative electrode 7. The positive electrode cell 2b and the positive electrode solution tank 4 are connected by a positive electrode solution circulation line 6, and the negative electrode cell 2a and the negative electrode solution tank 3
They are connected by a negative electrode liquid circulation line 9.

[0007] A pump 10 is provided in the positive electrode liquid circulation pipe 6, and a pump 11 is provided in the negative electrode liquid circulation circuit 9. A positive electrode electrolyte containing V ⁵⁺ / V ⁴⁺ is stored in the positive electrode tank 4, and a negative electrode electrolyte containing V ²⁺ / V ³⁺ is stored in the negative electrode tank 3. It is stored. These ions are respectively dissolved in the aqueous sulfuric acid solution.

In the all-vanadium redox flow battery, the V stored in the negative electrode liquid tank 3 is charged during charging.
A sulfuric acid aqueous solution containing 2 ⁺ / V ³⁺ is sent to the negative electrode cell 2 a by the pump 11, emits electrons to an external circuit at the negative electrode 7, oxidizes V ²⁺ to V ³⁺ , Collected. On the other hand, the sulfuric acid aqueous solution containing V ⁵⁺ / V ⁴⁺ ions stored in the positive electrode
b, the positive electrode 6 receives electrons from an external circuit, and V ⁵⁺ is reduced to V ⁴⁺ and collected in the positive electrode solution tank 4. In such an all-vanadium redox flow battery, the charge and discharge reactions in the positive electrode 6 and the negative electrode 7 are as follows:
It becomes like the following formula.

[0009]

Embedded image

[0010]

The conventional redox flow battery is configured as described above. By the way, as a tank for storing an electrolyte of an electrolyte flowing type battery such as a redox flow battery, a tank in which a resin such as vinyl chloride or FRP is lined on the inner surface of a metal tank, or a tank of a resin alone such as polyethylene or FRP is used. ing.

However, when an electrolyte-flowing battery such as a redox flow battery is installed in the basement of a building, it is necessary to store the electrolyte in an idle space under the ground, a so-called spring tank, in order to use the space effectively. However, it is difficult to install a metal tank or a simple resin tank in a spring tank. This is because underground spring tanks in buildings are often uneven and narrow in shape, and the entrances to the spring tanks are often manholes. This is because installation is difficult. In addition, since the redox flow battery is a system that performs charging and discharging by an oxidation-reduction reaction in the battery,
When oxygen enters from the outside, self-discharge occurs and battery efficiency decreases, so the tank needs to have a structure that does not allow oxygen to pass through. Therefore, a rubber bag tank is preferable as a tank that can be easily installed in the spring tank.

The present invention has been made to solve the above problems, and has as its object to provide an electrolyte tank that can be easily installed in terms of carrying in and assembling.

[0013] It is another object of the present invention to provide an improved electrolyte tank that is impermeable to oxygen.

[0014]

According to a first aspect of the present invention, there is provided an electrolytic solution tank for storing an electrolytic solution to be circulated through an electrode. The electrolyte tank is formed by processing a sheet obtained by laminating a plastic and a metal into a bag shape.

According to the present invention, by using a bag-shaped tank made of a sheet obtained by laminating a plastic and a metal for an electrolyte-flowing battery such as a redox flow battery, insulation and acid resistance are supplemented by plastic, Gas impermeability can be supplemented with metal. Also, unlike a metal tank or a resin single tank, it can be folded and carried into the underground spring tank from the manhole.

In the electrolyte tank according to the second aspect,
The sheet forming the electrolytic solution tank has a three-layer structure in which a polyester layer, an aluminum layer, and a polyethylene layer are sequentially laminated from the outside.

According to the present invention, the tank sheet is made of polyester, aluminum, or polyethylene from the outside.
By having a layer structure, heat-fusing properties of polyethylene,
Insulation, acid resistance, aluminum gas impermeability, lightweight,
Low cost and mechanical strength of polyester are obtained respectively. That is, in order to make the shape into a bag shape, it is necessary to bond the materials to each other, but if polyethylene is set inside, complete integration can be achieved by heat fusion. In addition, insulation and acid resistance are high. On the other hand, polyester has high mechanical strength and is suitable for the outer material. In addition, aluminum is low cost and lightweight.

In the electrolyte tank according to the third aspect,
The thickness of the polyethylene layer is 100 μm to 500 μm
It is.

According to the present invention, when the thickness of the polyethylene layer is set to 100 to 500 μm, it is possible to maintain the dielectric breakdown strength when a voltage is applied to the electrolytic solution, and to fold it to carry it in from the manhole. Becomes possible.
That is, since a voltage is applied to the electrolytic solution, 50 μm or more is required to maintain the dielectric breakdown strength. Further, in order to fold it into a small size, for example, when carrying it in from a manhole or the like, it is desirable that the thickness is about 1 mm or less. Therefore, 100μ
m-500 μm is considered optimal.

In the electrolyte tank according to the fourth aspect,
The electrolytic solution tank is placed over part or all of the floor surface, wall surface, and ceiling surface of the building, such as concrete of a building underground spring tank. This is to maintain the form as a bag-shaped tank, and to apply the static pressure and gas pressure of the liquid,
This is to endure the gas pressure.

According to the present invention, since the building is fixed by utilizing the strength of the concrete in the underground spring tank, no tensile strength is applied to the surface of the tank where the sheets are adhered to each other. That is, when the electrolytic solution is charged into the tank and pressure is applied, if tensile strength is applied to the surface where the sheets are bonded, the bonded surface may be peeled off. According to the present invention, this problem is prevented.

In the electrolyte tank according to the fifth aspect,
The electrolyte tank is fixed to a gantry. The gantry is installed, for example, in an underground spring tank of a building.

According to the present invention, by installing the gantry or the like and fixing the tank to the gantry, no tensile strength is applied to the surface of the tank where the sheets are adhered to each other.

In the electrolyte tank according to the sixth aspect,
The apparatus further includes means for measuring a resistance or a potential between the aluminum layer and the electrolyte.

According to the present invention, by measuring the resistance between the aluminum layer of the tank sheet and the electrolytic solution,
Should the polyethylene layer be damaged, such as a pinhole, the resistance or potential between the aluminum layer and the electrolyte drops sharply, so it can be detected instantaneously, and the polyester layer prevents the electrolyte from flowing out. .

In the electrolyte tank according to claim 7,
The sheet is elongated in a bag shape, a plurality of the electrolyte tanks are stacked, and water is allowed to flow through the gap.

According to the present invention, the electrolyte can be cooled without a general-purpose cooling device by stacking a plurality of tanks in an elongated structure and flowing water through the gaps. That is, in the redox flow battery, a loss in energy efficiency is converted into heat. Therefore, if the heat radiation is insufficient as in a building, the temperature of the battery rises and the deterioration is accelerated. According to the present invention, this requirement can be satisfied.

[0028] The invention according to claim 8 relates to a method of attaching a pipe to an electrolyte tank. An electrolytic solution tank is prepared by processing a sheet in which a polyester layer and a polyethylene layer are laminated with an aluminum layer interposed therebetween into a bag shape with the polyester layer facing out. The bag is turned upside down, a polyethylene pipe is inserted into the mouth, and then heat-sealed.

According to the present invention, it is possible to attach a pipe having excellent airtightness by turning over the mouth portion of the bag, inserting a polyethylene pipe into the mouth, and then performing heat sealing.

The invention according to claim 9 relates to a method for manufacturing a bag-like electrolyte tank by connecting three or more sheets.
A plurality of sheets in which a polyester layer and a polyethylene layer are laminated with an aluminum layer interposed therebetween are prepared.
The portions to be connected of the plurality of sheets are brought into contact with each other with a tape-like or cord-like polyethylene or a material having a lower melting point interposed therebetween, and heat-sealed.

According to the present invention, when bonding three or more sheets, tape-shaped or string-shaped polyethylene or a material having a melting point lower than that is inserted into a gap between a plurality of polyethylene layers and then heat-sealed. Thereby, airtightness can be secured. That is, when bonding three or more sheets, a gap is likely to be formed in the longitudinal direction of the bonding surface, and it is necessary to prevent the gap in order to ensure airtightness. According to the present invention, this can be satisfied.

[0032]

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

Embodiment 1 FIG. 1 is a sectional view of an electrolyte tank according to Embodiment 1.

Polyester layer 12 μm (21), aluminum layer 9 μm (22), polyethylene layer 100 μm
Two sheets laminated with (23) were produced, the respective polyethylene 23 sides were combined, and the ends were heat-sealed to produce a bag-like tank (hereinafter referred to as a lamination tank). In addition, it was confirmed that this tank could be easily folded and became compact. Two sets of these were prepared, and the respective electrolytes (vanadium sulfate) were charged as tanks for the positive electrode solution and the negative electrode solution, respectively.
The battery cell was connected with a polyethylene pipe. When this system was operated, there was no liquid leakage, corrosion, insulation resistance reduction, etc., and the system could be operated without any problem.

As a comparative example, a sheet tank having a polyethylene layer of 1 mm was prepared, but it was difficult to fold it. As a comparative example, the polyethylene layer was 30 μm.
A tank with a sheet thickness of m was prepared and operated in combination with the battery cell. However, the polyethylene layer did not maintain the dielectric breakdown strength, and was unable to operate.

The above-mentioned laminated sheet tank having a polyethylene layer of 100 μm was placed and fixed in a polyethylene tank simulating an underground spring tank so that no tensile strength was applied to the sheet bonding surface. Further, a pressure five times the pressure applied during normal battery operation was applied, but the sheet did not peel off.

When the resistance between the aluminum layer of the laminate sheet tank having a polyethylene layer of 100 μm and the electrolytic solution was measured, it was 100 MΩ or more. However, when a pinhole was formed in the polyethylene layer, the resistance became 1 MΩ or less. At this time, the electrolyte did not flow out.

Embodiment 2 The above-described laminated sheet tank having a polyethylene layer of 100 μm is placed inside a polyethylene tank simulating an underground spring tank, and water is further inserted between the polyethylene tank and the laminated sheet tank, and the operation is performed as described above. Did.
As a result, an increase in the liquid temperature was suppressed as compared with the case where no water was added.

In a redox flow battery, a loss in energy efficiency is converted into heat. Therefore, if the heat radiation is insufficient as in a building, the temperature of the battery rises and the deterioration is accelerated. According to the present embodiment, such a problem is solved.

Third Embodiment FIG. 2 relates to a method of mounting a pipe to an electrolyte tank according to a third embodiment. Two rectangular sheets on which a polyester layer 21, an aluminum layer 22, and a polyethylene layer 23 are laminated are prepared. Only three sides of two rectangular sheets are heat-sealed and processed into a bag shape. When attaching the laminate sheet tank and the polyethylene pipe, the mouth of the bag was turned upside down, and the polyethylene pipe 24 was inserted into the mouth, and then heat fusion was performed. As a result, the airtightness was maintained, and the battery operation was successfully performed.

According to the present embodiment, since the polyethylenes are heat-sealed to each other, it is possible to mount the pipe with excellent airtightness.

Embodiment 4 In the case where three laminated sheets are heat-sealed, a gap is formed in the longitudinal direction of the bonding surface, so that air-tightness cannot be ensured in some cases.

However, as shown in FIG. 3, when the string-like polyethylene 26 was inserted into the gap between the three polyethylene layers 23 and then heat-sealed, airtightness could be reliably ensured. The same effect can be obtained by using a tape-like polyethylene instead of a string-like polyethylene. The same effect can be realized by using a tape-shaped or cord-shaped material having a lower melting point instead of polyethylene.

The embodiments disclosed this time are to be considered in all respects as illustrative and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

[Brief description of the drawings]

FIG. 1 is a sectional view of an electrolyte tank according to a first embodiment.

FIG. 2 is a cross-sectional view showing a method for attaching a pipe to an electrolyte tank according to a third embodiment.

FIG. 3 is a cross-sectional view for explaining a method of manufacturing a bag-shaped electrolyte tank according to a fourth embodiment.

FIG. 4 is a conceptual diagram of a conventional redox flow battery.

[Explanation of symbols]

 21 Polyester layer 22 Aluminum layer 23 Polyethylene layer

Continued on the front page (72) Inventor Nobuyuki Tokuda 3-2-22-2 Nakanoshima, Kita-ku, Osaka-shi, Kansai Electric Power Company F-term (reference) 3E070 AA10 AB01 DA18 QA01 5H026 AA10 BB01 CX10 EE02 EE18 HH00 HH03

Claims (9)

[Claims] 1. An electrolytic solution tank for storing an electrolytic solution to be circulated and circulated through electrodes, wherein the electrolytic solution tank is formed by processing a sheet laminated with plastic and metal into a bag shape. 2. The electrolyte tank according to claim 1, wherein the sheet forming the electrolyte tank has a three-layer structure in which a polyester layer, an aluminum layer, and a polyethylene layer are sequentially stacked from the outside. 3. The thickness of the polyethylene layer is 100 μm.
The electrolyte tank according to claim 2, wherein the diameter is from m to 500 m. 4. The electrolytic solution tank according to claim 1, wherein the electrolytic solution tank is arranged so as to lean on part or all of a floor surface, a wall surface, and a ceiling surface of a building. 5. The electrolyte tank according to claim 1, wherein the electrolyte tank is fixed to a gantry installed in a building underground spring tank. 6. The electrolyte tank according to claim 2, further comprising means for measuring a resistance or a potential between the aluminum layer and the electrolyte. 7. The electrolyte tank according to claim 1, wherein the sheet is elongated in a bag shape, a plurality of the electrolyte tanks are stacked, and water is allowed to flow through the gap. 8. A sheet in which a polyester layer and a polyethylene layer are laminated with an aluminum layer interposed therebetween,
A step of preparing an electrolytic solution tank processed into a bag with the polyester layer outside, and a step of heat-sealing after turning over the mouth portion of the bag and inserting a polyethylene pipe into the mouth. A method of attaching piping to an electrolyte tank provided with: 9. A method for manufacturing a bag-shaped electrolyte tank by connecting three or more sheets, comprising preparing a plurality of sheets in which a polyester layer and a polyethylene layer are laminated with an aluminum layer interposed therebetween. And a portion to be connected to each of the plurality of sheets, a tape-shaped or string-shaped, polyethylene or a material having a lower melting point than that of the polyethylene, interposed, contacting each other, heat-fusing, A method for manufacturing an electrolytic solution tank comprising: