Redox flow battery

Abstract

To easily install an electrolytic solution tank.SOLUTION: A redox flow cell 1 includes an electrolyte tank 12 that is made by processing an existing fuel tank or an existing raw material tank such that an electrolyte can be accommodated. The electrolyte tank 12 has a first partition wall 42 that separates a first accommodating portion 60 that accommodates one of positive and negative electrolytes and a second accommodating portion 62 that accommodates the other of the positive and negative electrolytes. This allows the electrolyte tank 12 to be easily installed.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a redox flow battery. [Background technology]

[0002] For example, Patent Document 1 discloses an example of an electrolyte tank that contains an electrolyte in a redox flow battery. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 63-058771 Summary of the Invention [Problem to be solved by the invention]

[0004] In redox flow batteries, the battery capacity can be increased as the capacity of the electrolyte tank increases, so it is desirable to install a large electrolyte tank, but building a large electrolyte tank requires a large burden in terms of labor and cost.

[0005] Therefore, an object of the present invention is to provide a redox flow battery in which an electrolyte tank can be easily installed. [Means for solving the problem]

[0006] In order to solve the above problems, the redox flow battery of the present invention Manufacturing method The existing fuel tank or raw material tank is replaced with an electrolyte tank. of Can accommodate Electrolyte tank Processed into The process includes the step of: , The electrolyte tank is Located inside the electrolyte tank, A first partition wall that separates a first storage section in which an electrolyte for one of the positive electrode and the negative electrode is stored from a second storage section in which an electrolyte for the other of the positive electrode and the negative electrode is stored. and an inlet provided in each of the first storage section and the second storage section for feeding the electrolyte into the electrolyte tank, and an outlet provided in each of the first storage section and the second storage section for feeding the electrolyte out of the electrolyte tank, the first partition wall being disposed so as to reduce a flow path cross-sectional area of ​​the electrolyte flow path from the inlet to the outlet. . In order to solve the above problems, a manufacturing method of a redox flow battery of the present invention includes a step of processing an existing fuel tank or an existing raw material tank into an electrolyte tank capable of storing an electrolyte, the electrolyte tank having a first partition wall provided inside the electrolyte tank and dividing the electrolyte tank into a first storage section in which an electrolyte for one of the positive electrode or the negative electrode is stored and a second storage section in which an electrolyte for the other of the positive electrode or the negative electrode is stored, an inlet wall provided in each of the first storage section and the second storage section for feeding the electrolyte into the electrolyte tank, and an outlet wall provided in each of the first storage section and the second storage section for feeding the electrolyte out of the electrolyte tank, the first partition wall being installed so that the flow rate passing through a cross section perpendicular to the flow of the electrolyte from the inlet to the outlet is uniform within the cross section.

[0008] The electrolyte tank may have an auxiliary partition wall that separates a part of the inside of the first container or the second container.

[0010] Also , enter There may be more ports or outlets than the other.

[0011] The first partition wall may divide the first storage section and the second storage section into concentric circles.

[0012] The first partition may be disposed so that the volume of the first storage section is equal to the volume of the second storage section.

[0013] The electrolyte tank may also have a second partition therein that separates a hollow third container section capable of containing electrolyte from the first container section or the second container section.

[0014] The electrolyte tank may also have a bottom-raised portion that makes a portion of the bottom surface relatively higher.

[0015] In addition, the volume of electrolyte contained in the electrolyte tank may be limited based on a specific gravity ratio indicating the ratio of the specific gravity of the fuel that can be contained in the original fuel tank to the specific gravity of the electrolyte contained in the electrolyte tank, or the ratio of the specific gravity of the raw material that can be contained in the original raw material tank to the specific gravity of the electrolyte contained in the electrolyte tank.

[0016] Also, The electrolyte tank is The electrolyte tank may be provided with a coating material that is resistant to the electrolyte and is coated on the inner surface of the electrolyte tank, and the coating material may be coated to a height equal to or higher than an upper limit of the liquid level in the electrolyte tank, which is determined based on the specific gravity ratio.

[0017] The coating material may be applied in a removable manner. Effect of the Invention

[0019] According to the present invention, the electrolyte tank can be easily installed. [Brief description of the drawings]

[0020] [Figure 1] FIG. 1 is a schematic diagram showing the configuration of a redox flow battery according to a first embodiment. [Diagram 2] FIG. 2 is a horizontal cross-sectional view of the electrolyte tank. [Diagram 3] FIG. 3 is a schematic horizontal cross-sectional view of an electrolyte tank of a redox flow battery according to a second embodiment. [Figure 4] FIG. 4 is a schematic horizontal cross-sectional view of an electrolyte tank of a redox flow battery according to a third embodiment. [Diagram 5] FIG. 5 is a schematic horizontal cross-sectional view of an electrolyte tank of a redox flow battery according to a fourth embodiment. [Figure 6] FIG. 6 is a schematic horizontal cross-sectional view of an electrolyte tank of a redox flow battery according to a fifth embodiment. [Figure 7] FIG. 7 is a schematic horizontal cross-sectional view of an electrolyte tank of a redox flow battery according to a sixth embodiment. [Figure 8] FIG. 8 is a schematic horizontal cross-sectional view of an electrolyte tank of a redox flow battery according to a seventh embodiment. [Figure 9] FIG. 9 is a schematic diagram of an electrolyte tank of a redox flow battery according to an eighth embodiment. [Figure 10] FIG. 10 is a schematic diagram of an electrolyte tank of the redox flow battery according to the ninth embodiment. [Figure 11] FIG. 11 is a schematic horizontal cross-sectional view of an electrolyte tank of a redox flow battery according to a tenth embodiment. [Figure 12] FIG. 12 is a schematic horizontal sectional view of an electrolyte tank of a redox flow battery according to an eleventh embodiment. [Figure 13] FIG. 13 is a schematic diagram of a redox flow battery according to a twelfth embodiment. [Figure 14] FIG. 14 is a schematic diagram of a redox flow battery according to the thirteenth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] A preferred embodiment of the present invention will be described in detail below with reference to the accompanying drawings. The dimensions, materials, and other specific values ​​shown in the embodiment are merely examples for facilitating understanding of the invention, and do not limit the present invention unless otherwise specified. In this specification and drawings, elements having substantially the same functions and configurations are given the same reference numerals to avoid repeated explanations, and elements not directly related to the present invention are not shown.

[0022] (First embodiment) 1 is a schematic diagram showing the configuration of a redox flow battery 1 according to Embodiment 1. The redox flow battery 1 includes a cell stack 10, an electrolyte tank 12, a pump 14A, a pump 14B, a cooler 16A, and a cooler 16B.

[0023] The cell stack 10 includes a cell casing 20, an ion exchange membrane 22, a positive electrode 24, and a negative electrode 26. The cell casing 20 is formed in a hollow box shape. The ion exchange membrane 22 is provided so as to divide the inside of the cell casing 20 into two. The positive electrode 24 is accommodated in one side of the cell casing 20 divided by the ion exchange membrane 22. The negative electrode 26 is accommodated in the other side of the cell casing 20 divided by the ion exchange membrane 22. Hereinafter, the side of the cell casing 20 in which the positive electrode 24 is accommodated may be referred to as a positive electrode chamber, and the side of the cell casing 20 in which the negative electrode 26 is accommodated may be referred to as a negative electrode chamber.

[0024] The positive electrode 24 and the negative electrode 26 are connected to an electric power system 32 via a power converter 30. The cell stack 10 can be charged with power generated by a power source 34 connected to the electric power system 32. When charging the cell stack 10, the power converter 30 converts AC power from the electric power system 32 into DC power and supplies it to the cell stack 10. The cell stack 10 can also discharge stored power to the electric power system 32. When discharging the cell stack 10, the power converter 30 converts DC power from the cell stack 10 into AC power and supplies it to the electric power system 32. The power discharged to the electric power system 32 is consumed by a load 36 connected to the electric power system 32.

[0025] The positive electrode chamber contains the electrolyte for the positive electrode, and the negative electrode chamber contains the electrolyte for the negative electrode. Hereinafter, the electrolyte for the positive electrode and the electrolyte for the negative electrode may be collectively referred to simply as the electrolyte. The cross-hatching in FIG. 1 indicates that the electrolyte is contained.

[0026] The electrolyte for the positive electrode is, for example, a sulfuric acid solution containing tetravalent vanadium ions (V 4+ ) and pentavalent vanadium ions (V 5+ The electrolyte for the negative electrode contains, for example, a sulfuric acid solution containing trivalent vanadium ions (V 3+ ) and divalent vanadium ions (V 2+ The ion exchange membrane 22 allows, for example, hydrogen ions to pass through and blocks the passage of an aqueous sulfuric acid solution and vanadium ions.

[0027] When the cell stack 10 discharges, a current flows from the positive electrode 24 to the power grid 32. That is, in this case, electrons flow into the positive electrode 24. The pentavalent vanadium ions in the positive electrolyte combine with the electrons of the positive electrode 24, that is, are reduced by the electrons of the positive electrode 24 to become tetravalent vanadium ions. When the cell stack 10 discharges, electrons flow out from the negative electrode 26. The divalent vanadium ions in the negative electrolyte donate electrons to the negative electrode 26, that is, are oxidized by the negative electrode to become trivalent vanadium ions. During this oxidation-reduction reaction, the hydrogen ions in the negative electrolyte move to the positive electrolyte through the ion exchange membrane 22. This adjusts the charge balance in the electrolyte.

[0028] When the cell stack 10 is charged, a current flows from the power grid 32 to the positive electrode 24. That is, in this case, electrons flow out from the positive electrode 24. Tetravalent vanadium ions in the positive electrolyte donate electrons to the positive electrode 24, i.e., are oxidized by the positive electrode to become pentavalent vanadium ions. When the cell stack 10 is charged, electrons flow into the negative electrode 26. Trivalent vanadium ions in the negative electrolyte combine with electrons of the negative electrode 26, i.e., are reduced by the electrons of the negative electrode 26 to become divalent vanadium ions. During this oxidation-reduction reaction, hydrogen ions in the positive electrolyte move to the negative electrolyte through the ion exchange membrane 22. This adjusts the charge balance in the electrolyte.

[0029] The cell stack 10 is not limited to an embodiment using an electrolyte solution containing vanadium ions, and any electrolyte solution that allows the cell stack 10 to function appropriately for charging and discharging may be used.

[0030] The electrolyte tank 12 is an existing fuel tank or an existing raw material tank that has been processed so as to be capable of storing an electrolyte. For example, the electrolyte tank 12 is an existing liquefied natural gas (LNG) tank, an existing liquefied propane gas (LPG) tank, an existing gasoline tank, an existing raw material tank in a chemical plant, or the like. The existing fuel tank or the existing raw material tank is often large in itself. For this reason, by processing the existing fuel tank or the existing raw material tank into an electrolyte tank, it becomes possible to easily install a large electrolyte tank.

[0031] The electrolyte tank 12 has a tank housing 40, a first partition 42, a second partition 44, an auxiliary partition 46, and an auxiliary partition 48. The first partition 42 separates the tank into a first storage section 60 in which an electrolyte for either the positive electrode or the negative electrode is stored, and a second storage section 62 in which an electrolyte for the other of the positive electrode or the negative electrode is stored. The second partition separates a hollow third storage section 64 capable of storing an electrolyte from the first storage section 60 or the second storage section 62. The auxiliary partition 46 separates a part of the interior of the first storage section 60. The auxiliary partition 48 separates a part of the interior of the second storage section 62. The first partition 42, the second partition 44, the auxiliary partition 46, and the auxiliary partition 48 will be described in detail later.

[0032] The tank housing 40 is composed of a bottom surface portion 50, a side surface portion 52, and a top surface portion 54. The bottom surface portion 50 is formed in a disk shape. The side surface portion 52 stands vertically upward from the periphery of the bottom surface portion 50 and is formed in a cylindrical shape. The top surface portion 54 is connected to the upper edge of the side surface portion 52 and is formed in a circular dome shape. The tank housing 40 is formed hollow and sealed.

[0033] The first partition wall 42, the second partition wall 44, the auxiliary partition wall 46, and the auxiliary partition wall 48 are provided inside the tank housing 40. The first partition wall 42, the second partition wall 44, the auxiliary partition wall 46, and the auxiliary partition wall 48 are configured in a plate shape and stand vertically upward from the bottom surface portion 50. The heights of the first partition wall 42, the second partition wall 44, the auxiliary partition wall 46, and the auxiliary partition wall 48 are lower than the height of the side surface portion 52 and higher than the liquid level of the electrolyte.

[0034] 2 is a horizontal cross-sectional view of the electrolyte tank 12. The first partition wall 42 is formed in a cylindrical shape with a smaller diameter than the side wall portion 52 and is disposed concentrically with the side wall portion 52. The second partition wall 44 is formed in a cylindrical shape with a smaller diameter than the first partition wall 42 and is disposed concentrically with the side wall portion 52 and the first partition wall 42.

[0035] The first partition 42, the side surface portion 52, and the bottom surface portion 50 form a first storage portion 60. The first partition 42, the second partition 44, and the bottom surface portion 50 form a second storage portion 62. The second partition 44 and the bottom surface portion 50 form a third storage portion 64. The first partition 42 separates the first storage portion 60 from the second storage portion 62. The second partition 44 separates the second storage portion 62 from the third storage portion 64.

[0036] The first partition 42 and the second partition 44 are installed so that the volume of the first storage section 60, the volume of the second storage section 62, and the volume of the third storage section 64 are equal. Note that the first partition 42 and the second partition 44 may be installed so that at least the volume of the first storage section 60 and the volume of the second storage section 62 are equal, and the volume of the third storage section 64 may be different from the volume of the first storage section 60 and the volume of the second storage section 62.

[0037] The auxiliary partition 46 partitions a part of the interior of the first accommodating portion 60. Specifically, as shown in FIG. 2, the auxiliary partition 46 is provided at one circumferential location of the annular first accommodating portion 60 and divides the first accommodating portion 60 in the circumferential direction. The auxiliary partition 48 partitions a part of the interior of the second accommodating portion 62. Specifically, as shown in FIG. 2, the auxiliary partition 48 is provided at one circumferential location of the annular second accommodating portion 62 and divides the second accommodating portion 62 in the circumferential direction.

[0038] Returning to FIG. 1, the first storage section 60 contains an electrolyte for either the positive electrode or the negative electrode. The second storage section 62 contains an electrolyte for the other of the positive electrode or the negative electrode. In the example of FIG. 1 and FIG. 2, the first storage section 60 contains an electrolyte for the positive electrode, and the second storage section 62 contains an electrolyte for the negative electrode. Alternatively, the first storage section 60 may contain an electrolyte for the negative electrode, and the second storage section 62 may contain an electrolyte for the positive electrode. The third storage section 64 is hollow and does not contain an electrolyte.

[0039] The space above the first storage section 60 and the second storage section 62 is expanded and filled with nitrogen. The nitrogen filled space prevents the electrolyte in the first storage section 60 and the electrolyte in the second storage section 62 from deteriorating.

[0040] In this manner, by providing the first partition 42, both the positive electrode electrolyte and the negative electrode electrolyte can be accommodated in one electrolyte tank 12. As a result, if there is one or more existing fuel tanks or existing raw material tanks, they can be processed into the electrolyte tank 12 to configure the redox flow battery 1.

[0041] Since the electrolyte tank 12 is a modified version of an existing fuel tank or an existing raw material tank, the load capacity of the electrolyte tank 12 depends on the load capacity of the original fuel tank or the original raw material tank before being processed into the electrolyte tank 12. In addition, since the electrolyte is an aqueous sulfuric acid solution containing vanadium ions, it has a higher specific gravity than LNG, which is an example of the fuel contained in the original fuel tank. If the electrolyte tank 12 contains an electrolyte with a higher specific gravity than the original fuel in the same amount as the original fuel, there is a risk that the load of the electrolyte in the electrolyte tank 12 will exceed the load capacity of the electrolyte tank 12.

[0042] Therefore, when an existing fuel tank is processed, the volume of the electrolyte contained in the electrolyte tank 12 is limited based on a specific gravity ratio indicating the ratio of the specific gravity of the fuel that can be contained in the original fuel tank to the specific gravity of the electrolyte. Also, when an existing raw material tank is processed, the volume of the electrolyte contained in the electrolyte tank 12 is limited based on a specific gravity ratio indicating the ratio of the specific gravity of the raw material that can be contained in the original raw material tank to the specific gravity of the electrolyte. Note that, when multiple types of fuels can be contained in the original fuel tank, the specific gravity of the fuel with the highest specific gravity among the fuels that can be contained in the original fuel tank is adopted as the specific gravity of the fuel. Similarly, when multiple types of raw materials can be contained in the original raw material tank, the specific gravity of the raw material with the highest specific gravity among the raw materials that can be contained in the original raw material tank is adopted as the specific gravity of the raw material. This makes it possible to maximize the amount of electrolyte held in the electrolyte tank 12 while suppressing the load of the electrolyte in the electrolyte tank 12 to the load capacity of the electrolyte tank 12 or less.

[0043] The first storage section 60 and the second storage section 62 are subjected to a coating treatment that enables the storage of an electrolyte solution, since the electrolyte solution is stored in the first storage section 60 and the second storage section 62. The third storage section 64 may also be subjected to a coating treatment that enables the storage of an electrolyte solution.

[0044] Specifically, a coating material resistant to the electrolyte is applied to the inner surface of the electrolyte tank 12. The inner surface of the electrolyte tank 12 includes the side surface of the side portion 52, the upper surface of the bottom portion 50, the side surface of the first partition 42, the side surface of the second partition 44, the side surface of the auxiliary partition 46, and the side surface of the auxiliary partition 48. The coating material is, for example, a rubber material, but any material resistant to the sulfuric acid aqueous solution can be used. The coating material is not limited to being applied, and for example, a plate material made of rubber or the like may be mechanically attached to the inner surface of the electrolyte tank 12. The coating material may be attached in a detachable manner.

[0045] As described above, the capacity of the electrolyte is limited based on the specific gravity of the electrolyte and the specific gravity ratio of the original fuel or the original raw material. This determines the upper limit of the liquid level of the electrolyte in the electrolyte tank 12. Therefore, the coating material is coated to a height equal to or higher than the upper limit of the liquid level in the electrolyte tank 12 determined based on the specific gravity ratio. In other words, the coating material needs to be coated at least up to the upper limit of the liquid level, and does not necessarily have to be coated up to the upper edge of the side portion 52. This makes it possible to reduce the burden of processing the electrolyte tank 12 while suppressing deterioration of the electrolyte tank 12 due to the electrolyte.

[0046] The pumps 14A and 14B are configured in a cylindrical shape. The pump 14A is disposed vertically in the first storage section 60. The pump 14B is disposed vertically in the second storage section 62. Hereinafter, the pumps 14A and 14B may be collectively referred to simply as pumps. The lower end of the pump is disposed near the bottom surface section 50 and spaced apart from the bottom surface section 50. The pump is provided penetrating the top surface section 54 of the electrolyte tank 12, and the upper end of the pump is located outside the electrolyte tank 12.

[0047] The pump 14A is connected to a discharge pipe 70A. The discharge pipe 70A is connected to the positive electrode chamber of the cell stack 10. The positive electrode chamber is also connected to a withdrawal pipe 72A. The withdrawal pipe 72A extends to the first storage section 60 of the electrolyte tank 12. The pump 14A sucks up the electrolyte of the positive electrode in the first storage section 60 and supplies it to the positive electrode chamber of the cell stack 10 through the discharge pipe 70A. The electrolyte in the positive electrode chamber is returned to the first storage section 60 through the withdrawal pipe 72A.

[0048] The pump 14B is connected to a discharge pipe 70B. The discharge pipe 70B is connected to the negative electrode chamber of the cell stack 10. The negative electrode chamber is also connected to a withdrawal pipe 72B. The withdrawal pipe 72B extends to the second storage section 62 of the electrolyte tank 12. The pump 14B sucks up the electrolyte of the negative electrode in the second storage section 62 and supplies it to the negative electrode chamber of the cell stack 10 through the discharge pipe 70B. The electrolyte in the negative electrode chamber is returned to the second storage section 62 through the withdrawal pipe 72B.

[0049] The pump 14A circulates the positive electrode electrolyte between the electrolyte tank 12 and the cell stack 10. The pump 14B circulates the negative electrode electrolyte between the electrolyte tank 12 and the cell stack 10. Circulating the electrolyte by the pump promotes charging and discharging in the cell stack 10. The pump is not limited to being cylindrical and vertically disposed. For example, the pump may be cylindrical or horizontally disposed. For example, the pump may have various shapes other than a cylindrical shape and be disposed outside the electrolyte tank 12.

[0050] The cooler 16A is provided midway along the withdrawal pipe 72A extending from the positive electrode chamber. The cooler 16A cools the electrolyte flowing from the positive electrode chamber to the first storage section 60. The cooler 16B is provided midway along the withdrawal pipe 72B extending from the negative electrode chamber. The cooler 16B cools the electrolyte flowing from the negative electrode chamber to the second storage section 62.

[0051] A flow rate adjustment valve 74A is provided between the positive electrode chamber and the cooler 16A in the withdrawal pipe 72A. A flow rate measurement device 76A is provided in the dispensing pipe 70A. The flow rate measurement device 76A measures the flow rate of the electrolyte flowing through the dispensing pipe 70A. A flow rate control device (not shown) controls the opening degree of the flow rate adjustment valve 74A based on the flow rate measured by the flow rate measurement device 76A.

[0052] In addition, a pump minimum flow pipe 78A is connected between the flow rate measuring device 76A and the positive electrode chamber in the dispensing pipe 70A. The pump minimum flow pipe 78A extends to the first storage section 60. A pump minimum flow control valve 80A is provided midway along the pump minimum flow pipe 78A. An unillustrated flow control device controls the opening of the pump minimum flow control valve 80A based on the flow rate measured by the flow rate measuring device 76A.

[0053] A flow rate adjustment valve 74B is provided between the negative electrode chamber and the cooler 16B in the withdrawal pipe 72B. A flow rate measurement device 76B is provided in the dispensing pipe 70B. The flow rate measurement device 76B measures the flow rate of the electrolyte flowing through the dispensing pipe 70B. A flow rate control device (not shown) controls the opening degree of the flow rate adjustment valve 74B based on the flow rate measured by the flow rate measurement device 76B.

[0054] In addition, a pump minimum flow pipe 78B is connected between the flow rate measuring device 76B and the negative electrode chamber in the dispensing pipe 70B. The pump minimum flow pipe 78B extends to the second storage section 62. A pump minimum flow adjustment valve 80B is provided midway along the pump minimum flow pipe 78B. An unillustrated flow control device controls the opening of the pump minimum flow adjustment valve 80B based on the flow rate measured by the flow rate measuring device 76B.

[0055] An electrolyte supply pipe 82A is connected to the pump minimum flow pipe 78A on the electrolyte tank 12 side of the pump minimum flow control valve 80A. A shutoff valve 84A is provided in the electrolyte supply pipe 82A. The shutoff valve 84A is normally closed. When the shutoff valve 84A is opened, the positive electrode electrolyte is supplied to the first storage section 60 through the electrolyte supply pipe 82A and the pump minimum flow pipe 78A.

[0056] An electrolyte supply pipe 82B is connected to the pump minimum flow pipe 78B on the electrolyte tank 12 side of the pump minimum flow control valve 80B. A shutoff valve 84B is provided in the electrolyte supply pipe 82B. The shutoff valve 84B is normally closed. When the shutoff valve 84B is opened, the negative electrode charged liquid is supplied to the second storage section 62 through the electrolyte supply pipe 82B and the pump minimum flow pipe 78B.

[0057] The nitrogen supply pipe 86 extends from the outside of the electrolyte tank 12 through the top surface 54 into the electrolyte tank 12. Nitrogen is supplied into the electrolyte tank 12 through the nitrogen supply pipe 86. A nitrogen supply control valve 88 is provided midway along the nitrogen supply pipe 86. The nitrogen release pipe 90 extends from the inside of the electrolyte tank 12 through the top surface 54 to the outside of the electrolyte tank 12. The nitrogen-containing gas filled in the electrolyte tank 12 is released to the outside of the electrolyte tank 12 through the nitrogen release pipe 90. A nitrogen release control valve 92 is provided midway along the nitrogen release pipe 90.

[0058] A pressure measuring device 94 is provided on the top surface 54 of the electrolyte tank 12. The pressure measuring device 94 measures the pressure inside the electrolyte tank 12. A pressure control device (not shown) controls the aperture of the nitrogen supply adjustment valve 88 and the aperture of the nitrogen release adjustment valve 92 so that the pressure inside the electrolyte tank 12 measured by the pressure measuring device 94 is maintained at a predetermined pressure.

[0059] A branch pipe 96 is connected to the nitrogen release pipe 90 between the electrolyte tank 12 and the nitrogen release control valve 92. A shutoff valve 98 is provided midway through the branch pipe 96. The shutoff valve 98 is normally closed. When the shutoff valve 98 is opened, the nitrogen-containing gas in the electrolyte tank 12 is released to the outside of the electrolyte tank 12 through the nitrogen release pipe 90 and the branch pipe 96.

[0060] Here, the electrolyte flowing through the withdrawal pipe 72A and the withdrawal pipe 72B flows into the electrolyte tank 12 through the withdrawal port 100 that opens in the electrolyte tank 12. In other words, the withdrawal port 100 of the withdrawal pipe 72A and the withdrawal pipe 72B corresponds to an inlet for feeding the electrolyte into the electrolyte tank 12. The electrolyte in the electrolyte tank 12 flows out of the electrolyte tank 12 through the suction port 102 at the tip of the pump 14A and the pump 14B. In other words, the suction port 102 of the pump 14B corresponds to an outlet for feeding the electrolyte out of the electrolyte tank 12. The inlet and outlet of the electrolyte are disposed in the first storage section 60 and the second storage section 62, respectively. In FIG. 2, the withdrawal port 100 that corresponds to the inlet is indicated by "◯", and the suction port 102 that corresponds to the outlet is indicated by "◎".

[0061] As shown in FIG. 2, the withdrawal port 100 of the first storage section 60 is located near the auxiliary partition wall 46 on one side (the right side in FIG. 2) separated by the auxiliary partition wall 46. The suction port 102 of the first storage section 60 is located near the auxiliary partition wall 46 on the other side (the left side in FIG. 2) separated by the auxiliary partition wall 46. Then, the electrolyte sent from the withdrawal port 100 to the first storage section 60 flows in one direction (the clockwise direction in FIG. 2) through the annular first storage section 60 toward the suction port 102 of the first storage section 60, as shown by the dashed arrow A10 in FIG. 2. This allows the electrolyte in the first storage section 60 to flow smoothly.

[0062] As a comparative example, the inside of the electrolyte tank 12 may be simply divided into two so that the horizontal cross sections of the first storage section 60 and the second storage section 62 are semicircular. The withdrawal port 100 and the inlet port 102 are spaced apart from each other so that the flow path of the electrolyte from the withdrawal port 100 to the inlet port 102 is long. In this comparative example, the width of the electrolyte flow path is relatively wide.

[0063] In contrast, in the electrolyte tank 12 of the first embodiment, the first storage section 60 is formed in a circular ring shape. Therefore, in the first storage section 60 of the first embodiment, the electrolyte flow path from the withdrawal port 100 to the suction port 102 is narrower than in the semicircular shape of the comparative example. In the first storage section 60 of the first embodiment, the flow path is longer accordingly. This corresponds to the fact that in the first embodiment, the flow path cross-sectional area of ​​the electrolyte flow path in the first storage section 60 is smaller than in the comparative example. In other words, the first partition wall 42 is installed so as to reduce the flow path cross-sectional area of ​​the electrolyte flow path from the inlet to the outlet. The flow path cross-sectional area indicates the cross-sectional area perpendicular to the longitudinal direction of the flow path. Therefore, in the electrolyte tank 12 of the first embodiment, the flow rate of the electrolyte flowing through the first storage section 60 can be increased, and stagnation of the electrolyte in the first storage section 60 can be suppressed.

[0064] In addition, since the first storage section 60 is formed in an annular shape, the flow rate passing through a cross section perpendicular to the flow of the electrolyte can be made uniform within the cross section. In other words, the first partition 42 is installed so that the flow rate passing through a cross section perpendicular to the flow of the electrolyte is made uniform within the cross section. Note that the term "uniform" is not limited to a state in which the flow rates are the same, but includes a state in which the flow rates may differ within a predetermined range that can be recognized as being approximately the same. From this point of view, it is also possible to suppress stagnation of the electrolyte in the first storage section 60.

[0065] As shown in FIG. 2, the withdrawal port 100 of the second storage section 62 is located near the auxiliary partition wall 48 on one side (the right side in FIG. 2) separated by the auxiliary partition wall 48. The suction port 102 of the second storage section 62 is located near the auxiliary partition wall 48 on the other side (the left side in FIG. 2) separated by the auxiliary partition wall 48. Then, the electrolyte sent from the withdrawal port 100 to the second storage section 62 flows in one direction (the clockwise direction in FIG. 2) through the annular second storage section 62 toward the suction port 102 of the second storage section 62, as shown by the two-dot chain arrow A12 in FIG. 2. This allows the electrolyte in the second storage section 62 to flow smoothly.

[0066] Similarly to the first storage section 60, the second storage section 62 has a smaller flow path cross-sectional area of ​​the electrolyte flow path from the withdrawal port 100 to the inlet port 102. This makes it possible to increase the flow rate of the electrolyte flowing through the second storage section 62, and to prevent the electrolyte from stagnating in the second storage section 62.

[0067] In addition, the second storage section 62 can make the flow speed passing through a cross section perpendicular to the flow of the electrolyte uniform within the cross section, similar to the first storage section 60. This makes it possible to suppress stagnation of the electrolyte within the second storage section 62.

[0068] As described above, the redox flow battery 1 of the first embodiment includes the electrolyte tank 12, which is an existing fuel tank or an existing raw material tank that has been modified so as to be capable of containing an electrolyte. Therefore, in the redox flow battery 1 of the first embodiment, it is not necessary to construct the electrolyte tank 12 from scratch, and the burden of construction labor and costs can be reduced. Therefore, according to the redox flow battery 1 of the first embodiment, the electrolyte tank 12 can be easily installed.

[0069] Moreover, in the redox flow battery 1 of the first embodiment, the first partition wall 42 that separates the first storage section 60 and the second storage section 62 is provided inside the electrolyte tank. Therefore, in the redox flow battery 1 of the first embodiment, it is not necessary to provide a plurality of electrolyte tanks 12, and the electrolyte tank 12 can be easily installed.

[0070] In addition, the existing fuel tank or the existing raw material tank is often large in itself. In the redox flow battery 1 of the first embodiment, the existing fuel tank or the existing raw material tank is processed into the electrolyte tank 12, so that the large electrolyte tank 12 can be easily installed.

[0071] Furthermore, existing LNG tanks and the like may be owned by, for example, power generation companies. It is conceivable that in the future, power generation companies will increase the proportion of power generation using natural energy and decrease the proportion of thermal power generation using LNG. In that case, the reduction in LNG usage may result in existing LNG tanks becoming surplus. By converting such surplus existing LNG tanks into electrolyte tanks 12, it becomes possible to meaningfully reuse unnecessary assets.

[0072] Furthermore, by converting an existing LNG tank of a power generation company into an electrolyte tank 12 and introducing the redox flow battery 1 of the first embodiment, the power generation company can stabilize the power system while suppressing an increase in equipment.

[0073] Second embodiment 3 is a schematic horizontal cross-sectional view of an electrolyte tank of a redox flow battery according to the second embodiment. In the first embodiment, a third storage section 64 that does not store an electrolyte is formed. In contrast, the second embodiment differs from the first embodiment in that the third storage section 64 is not formed.

[0074] In the electrolyte tank 212A of FIG. 3A, the inside of the electrolyte tank 212A is divided into two by a first partition wall 220 formed in a cylindrical shape concentric with the side surface portion 52. The first storage section 60 is formed in an annular shape. The first storage section 60 is provided with an auxiliary partition wall 222 that separates a part of the first storage section 60. In other words, the first storage section 60 has the same shape as the first storage section 60 of the first embodiment. Therefore, in the electrolyte tank 212A of FIG. 3A as well, it is possible to suppress stagnation of the electrolyte in the first storage section 60.

[0075] The second storage section 62 is formed in a cylindrical shape. The second storage section 62 is provided with an auxiliary partition 224 that partitions a part of the second storage section 62. The auxiliary partition 224 extends in the radial direction from the intersection of the first partition 220 with the auxiliary partition 222 of the first storage section 60. The auxiliary partition 224 is spaced apart from the first partition 220 on the opposite side to the auxiliary partition 222. The withdrawal port 100 of the second storage section 62 is located near the auxiliary partition 224 and the first partition 220 on one side (the right side in FIG. 3A) partitioned by the auxiliary partition 224. The suction port 102 of the second storage section 62 is located near the auxiliary partition 224 and the first partition 220 on the other side (the left side in FIG. 3A) partitioned by the auxiliary partition 224.

[0076] The electrolyte solution sent from the withdrawal port 100 of the second storage section 62 flows toward the suction port 102 of the second storage section 62, bypassing the auxiliary partition wall 224, as indicated by the two-dot chain arrow A22 in FIG. 3A.

[0077] 3A is provided with auxiliary partition 224, the flow path cross-sectional area of ​​the electrolyte flow path is smaller than in a configuration without auxiliary partition 224. Therefore, it is possible to prevent stagnation of the electrolyte in second storage unit 62 also in electrolyte tank 212A in FIG.

[0078] In addition, in the electrolyte tank 212A of FIG. 3A, since the third storage section 64 is not formed, the volumes of the first storage section 60 and the second storage section 62 can be increased accordingly, and the capacity of the redox flow battery can be increased.

[0079] The electrolyte tank 212B in FIG. 3B differs from the electrolyte tank 212A in FIG. 3A in terms of the arrangement of the withdrawal port 100 and the suction port 102 of the second storage section 62. In the electrolyte tank 212B in FIG. 3B, the withdrawal port 100 is arranged on both one side and the other side partitioned by the auxiliary partition 224 in the second storage section 62. In addition, the suction port 102 of the second storage section 62 is arranged between the end of the auxiliary partition 224 on the opposite side to the auxiliary partition 222 and the first partition 220. That is, in the electrolyte tank 212B in FIG. 3B, the number of withdrawal ports 100 is greater than the number of suction ports 102 in the second storage section 62.

[0080] In the electrolyte tank 212B of Figure 3B, as shown by the dotted line arrow A24 in Figure 3B, the electrolyte supplied from one of the withdrawal ports 100 of the second storage section 62 flows toward the suction port 102, while the electrolyte supplied from the other withdrawal port 100 of the second storage section 62 flows toward the suction port 102.

[0081] 3B, by increasing the number of withdrawal ports 100 of the second storage section 62, it is possible to suppress a large change in the direction of the flow that would otherwise bypass the auxiliary partition wall 224. Therefore, in the electrolyte tank 212B of FIG. 3B, it is possible to further suppress stagnation of the electrolyte in the second storage section 62.

[0082] The electrolyte tank 212C in FIG. 3C differs from the electrolyte tank 212B in FIG. 3B in terms of the arrangement of the withdrawal port 100 and the suction port 102 of the first storage unit 60. In the electrolyte tank 212C in FIG. 3C, the withdrawal port 100 is arranged on both one side and the other side partitioned by the auxiliary partition wall 222 in the first storage unit 60. In addition, the suction port 102 of the first storage unit 60 is arranged at a position furthest in the circumferential direction from the position of the auxiliary partition wall 222 in the first storage unit 60. That is, in the electrolyte tank 212C in FIG. 3C, the number of withdrawal ports 100 is greater than the number of suction ports 102 in the first storage unit 60.

[0083] In the electrolyte tank 212C of Figure 3C, as shown by the dotted arrow A26 in Figure 3C, the electrolyte supplied from one of the withdrawal ports 100 of the first storage section 60 flows toward the suction port 102, while the electrolyte supplied from the other withdrawal port 100 of the first storage section 60 flows toward the suction port 102.

[0084] In the electrolyte tank 212C of Figure 3C, by increasing the number of withdrawal ports 100 in the first storage section 60, the distance from the withdrawal ports 100 to the suction port 102 is shortened, and the electrolyte sent to the first storage section 60 can be discharged more quickly, thereby improving the circulation efficiency of the electrolyte.

[0085] Third embodiment 4 is a schematic horizontal cross-sectional view of an electrolyte tank of a redox flow battery according to a third embodiment. In the second embodiment, the electrolyte tank is divided into two parts in a concentric circle shape. In contrast, in the third embodiment, the electrolyte tank is divided into two parts in a semicircular shape.

[0086] In the electrolyte tank 312A of Fig. 4A, the inside of the electrolyte tank 312A is divided into two by a radially extending first partition wall 320. The first storage section 60 is formed so that its horizontal cross section is semicircular on one side (the left side in Fig. 4A) separated by the first partition wall 320. The second storage section 62 is formed so that its horizontal cross section is semicircular on the other side (the right side in Fig. 4A) separated by the first partition wall 320.

[0087] The withdrawal port 100 of the first storage unit 60 is disposed near one end (lower side in FIG. 4A) of the electrolyte tank 312A in the first partition 320 in the radial direction. The suction port 102 of the first storage unit 60 is disposed near the other end (upper side in FIG. 4A) of the electrolyte tank 312A in the first partition 320 in the radial direction. The withdrawal port 100 of the second storage unit 62 is disposed near one end (lower side in FIG. 4A) of the electrolyte tank 312A in the first partition 320 in the radial direction. The suction port 102 of the second storage unit 62 is disposed near the other end (upper side in FIG. 4A) of the electrolyte tank 312A in the first partition 320 in the radial direction.

[0088] In the example of FIG. 4A, the first storage section 60 and the second storage section 62 can be separated by the first partition wall 320 which is a flat plate, and the electrolyte tank 312A can be easily configured.

[0089] The electrolyte tank 312B of FIG. 4B is different from the electrolyte tank 312A of FIG. 4A in terms of the arrangement of the withdrawal port 100 and the suction port 102. In the first storage section 60 of the electrolyte tank 312B of FIG. 4B, a plurality of withdrawal ports 100 are arranged near the side surface portion 52. The plurality of withdrawal ports 100 are arranged in a dispersed manner in the circumferential direction of the side surface portion 52. For example, five withdrawal ports 100 of the first storage section 60 are provided at equal intervals in the circumferential direction of the side surface portion 52. The number of withdrawal ports 100 is not limited to five, and it is sufficient that a plurality of withdrawal ports 100 are distributed in the vicinity of the side surface portion 52. In addition, the suction port 102 of the first storage section 60 is arranged near the center of the electrolyte tank 312B.

[0090] In the second storage section 62 of the electrolyte tank 312B in Fig. 4B, similar to the first storage section 60, a plurality of withdrawal ports 100 are dispersed and disposed near the side surface section 52. Also, the suction port 102 of the second storage section 62 is disposed near the center of the electrolyte tank 312B. Thus, in Fig. 4B, the number of withdrawal ports 100 is greater than the number of suction ports 102.

[0091] In the electrolyte tank 312B in Fig. 4B, as shown by the dashed-dotted arrows in Fig. 4B, the electrolyte delivered from each withdrawal port 100 of the first storage unit 60 flows toward the suction port 102 of the first storage unit 60. Also, in the electrolyte tank 312B in Fig. 4B, as shown by the dashed-dotted arrows in Fig. 4B, the electrolyte delivered from each withdrawal port 100 of the second storage unit 62 flows toward the suction port 102 of the second storage unit 62.

[0092] In the electrolyte tank 312B of Fig. 4B, by increasing the number of withdrawal ports 100, the flow rate passing through a cross-sectional area perpendicular to the flow of the electrolyte from the withdrawal ports 100 to the inlet port 102 can be made uniform within that cross section. Therefore, in the electrolyte tank 312B of Fig. 4B, it is possible to suppress stagnation of the electrolyte in the first storage section 60 and the second storage section 62.

[0093] (Fourth embodiment) 5 is a schematic horizontal cross-sectional view of an electrolyte tank of a redox flow battery according to a fourth embodiment. In the third embodiment, the electrolyte tank is divided into two semicircular sections. In contrast, in the fourth embodiment, the electrolyte tank is divided into two semicircular sections.

[0094] In the electrolyte tank 412 of Fig. 5, the inside of the electrolyte tank 412 is divided into two by a first partition wall 420 made of a curved plate bent into an S shape. The first storage section 60 is formed on one side (the left side in Fig. 5) separated by the first partition wall 420, and the second storage section 62 is formed on the other side (the right side in Fig. 5) separated by the first partition wall 420. The first storage section 60 and the second storage section 62 each have a horizontal cross-sectional shape resembling a double-cross bracket.

[0095] The withdrawal port 100 of the first storage section 60 is disposed near the connection between the first partition wall 420 and the side surface portion 52 in a portion where the horizontal cross-sectional area of ​​the first storage section 60 is large. The intake port 102 of the first storage section 60 is disposed near the connection between the first partition wall 420 and the side surface portion 52 in a portion where the horizontal cross-sectional area of ​​the first storage section 60 is small. The withdrawal port 100 of the second storage section 62 is disposed near the connection between the first partition wall 420 and the side surface portion 52 in a portion where the horizontal cross-sectional area of ​​the second storage section 62 is large. The intake port 102 of the second storage section 62 is disposed near the connection between the first partition wall 420 and the side surface portion 52 in a portion where the horizontal cross-sectional area of ​​the second storage section 62 is small.

[0096] As shown by the dashed-dotted arrow in Fig. 5, the electrolyte solution fed from the withdrawal port 100 of the first storage section 60 flows from the portion with the larger horizontal cross-sectional area to the portion with the smaller horizontal cross-sectional area. Also, as shown by the dashed-dotted arrow in Fig. 5, the electrolyte solution fed from the withdrawal port 100 of the second storage section 62 flows from the portion with the larger horizontal cross-sectional area to the portion with the smaller horizontal cross-sectional area.

[0097] 5, the flow rate through a cross-sectional area perpendicular to the flow of the electrolyte from the withdrawal port 100 to the inlet port 102 can be made uniform within the cross section. Therefore, in the electrolyte tank 412 of FIG. 5, it is possible to suppress stagnation of the electrolyte within the first storage section 60 and the second storage section 62.

[0098] Fifth embodiment 6 is a schematic horizontal cross-sectional view of an electrolyte tank of a redox flow battery according to a fifth embodiment. In the third embodiment, the electrolyte tank is divided into two semicircular compartments. In the fourth embodiment, the first and second container sections 60 and 62 are further divided into semicircular compartments.

[0099] In the electrolyte tank 512A of FIG. 6A, the auxiliary partition 522 is disposed in the first storage section 60 so as to be parallel to the first partition 320. One horizontal end (upper end in FIG. 6A) of the auxiliary partition 522 is connected to the side surface section 52, and the other horizontal end (lower end in FIG. 6A) of the auxiliary partition 522 is spaced apart from the side surface section 52. The auxiliary partition 524 is disposed in the second storage section 62 so as to be parallel to the first partition 320. One horizontal end (upper end in FIG. 6A) of the auxiliary partition 524 is connected to the side surface section 52, and the other horizontal end (lower end in FIG. 6A) of the auxiliary partition 524 is spaced apart from the side surface section 52. The auxiliary partition 522 and the auxiliary partition 524 are disposed so as to be line-symmetrical with respect to the first partition 320.

[0100] The suction port 102 of the first storage section 60 is disposed near the side surface portion 52 between the first partition 320 and the auxiliary partition 522. The withdrawal port 100 of the first storage section 60 is disposed near the connection portion of the side surface portion 52 and the auxiliary partition 522, on the opposite side of the first partition 320 with respect to the auxiliary partition 522. The suction port 102 of the second storage section 62 is disposed near the side surface portion 52 between the first partition 320 and the auxiliary partition 524. The withdrawal port 100 of the second storage section 62 is disposed near the connection portion of the side surface portion 52 and the auxiliary partition 524, on the opposite side of the first partition 320 with respect to the auxiliary partition 524.

[0101] In the electrolyte tank 512A of Fig. 6A, the flow path cross-sectional area of ​​the electrolyte flow path in each of the first storage section 60 and the second storage section 62 is smaller than that in the electrolyte tank 312A of Fig. 4A. Therefore, in the electrolyte tank 512A of Fig. 6A, it is possible to suppress stagnation of the electrolyte in the first storage section 60 and the second storage section 62.

[0102] In the electrolyte tank 512B of FIG. 6B, the auxiliary partition 522 and the auxiliary partition 524 are arranged so as to be point symmetric with respect to the center of the electrolyte tank 512B. In the electrolyte tank 512B of FIG. 6B, similar to the electrolyte tank 512A of FIG. 6A, the flow path cross-sectional area of ​​the electrolyte flow path in each of the first storage section 60 and the second storage section 62 is small. Therefore, in the electrolyte tank 512B of FIG. 6B, similar to the electrolyte tank 512A of FIG. 6A, it is possible to suppress stagnation of the electrolyte in the first storage section 60 and the second storage section 62.

[0103] In the electrolyte tank 512C of FIG. 6C, two auxiliary partition walls 532 and 534 are provided in the first storage section 60, and two auxiliary partition walls 536 and 538 are provided in the second storage section 62. The two auxiliary partition walls 532 and 534 in the first storage section 60 are arranged parallel to the first partition wall 320. One horizontal end (upper end in FIG. 6C) of the auxiliary partition wall 532 is connected to the side surface section 52, and the other horizontal end (lower end in FIG. 6C) of the auxiliary partition wall 532 is separated from the side surface section 52. One horizontal end (upper end in FIG. 6C) of the auxiliary partition wall 534 is separated from the side surface section 52, and the other horizontal end (lower end in FIG. 6C) of the auxiliary partition wall 534 is connected to the side surface section 52.

[0104] The suction port 102 of the first storage section 60 is disposed near the side surface portion 52 between the first partition 320 and the auxiliary partition 532. The withdrawal port 100 of the first storage section 60 is disposed near the connection between the side surface portion 52 and the auxiliary partition 534 on the opposite side of the first partition 320 with respect to the auxiliary partition 534. In other words, the first storage section 60 has a labyrinth structure. The auxiliary partition 536, the auxiliary partition 538, the withdrawal port 100 and the suction port 102 of the second storage section 62 are disposed so that the auxiliary partition 532, the auxiliary partition 534, the withdrawal port 100 and the suction port 102 of the first storage section 60 are laterally inverted with respect to the first partition 320.

[0105] In the electrolyte tank 512C of Fig. 6C, the flow path cross-sectional area of ​​the electrolyte flow path in each of the first storage unit 60 and the second storage unit 62 is smaller than that in the electrolyte tank 512A of Fig. 6A and the electrolyte tank 512B of Fig. 6B. Therefore, in the electrolyte tank 512C of Fig. 6C, it is possible to further suppress stagnation of the electrolyte in the first storage unit 60 and the second storage unit 62.

[0106] Sixth embodiment Fig. 7 is a schematic horizontal cross-sectional view of an electrolyte tank of a redox flow battery according to Embodiment 6. In the electrolyte tank 612 of Fig. 7, a first partition wall 620 is provided so that the first container section 60 and the second container section 62 are formed in a spiral shape.

[0107] In the electrolyte tank 612 of Fig. 7, the flow path cross-sectional area of ​​the electrolyte flow path in each of the first storage section 60 and the second storage section 62 is smaller than that in the electrolyte tank 412 of Fig. 5. Therefore, in the electrolyte tank 612 of Fig. 7, it is possible to further suppress stagnation of the electrolyte in the first storage section 60 and the second storage section 62.

[0108] Seventh embodiment FIG. 8 is a schematic horizontal cross-sectional view of an electrolyte tank of a redox flow battery according to a seventh embodiment. In the electrolyte tank 712 of FIG. 8, a first partition wall 720 is composed of a cylindrical first piece 722, a flat second piece 724, and a flat third piece 726. The first piece 722 is arranged concentrically with the side surface portion 52. The second piece 724 is arranged along the radial direction of the side surface portion 52 and is connected to the first piece 722 and the side surface portion 52. The third piece 726 is arranged along the radial direction of the side surface portion 52 on the opposite side of the first piece 722 to the second piece 724, and is connected to the first piece 722 and the side surface portion 52. The first storage portion 60 and the second storage portion 62 are formed in a semicircular ring shape by the first partition wall 720.

[0109] The first storage section 60 is provided with an auxiliary partition wall 730. The auxiliary partition wall 730 extends from the first piece 722 in the circumferential direction of the first storage section 60, and divides the first storage section 60 into an inner peripheral side and an outer peripheral side. The end of the auxiliary partition wall 730 opposite to the first piece 722 is separated from the second piece 724, and the inner peripheral side and the outer peripheral side are in communication. The withdrawal port 100 of the first storage section 60 is disposed near the first piece 722 on the inner peripheral side. The suction port 102 of the first storage section 60 is disposed near the first piece 722 on the outer peripheral side. The electrolyte solution flowing in from the withdrawal port 100 of the first storage section 60 flows in the order from the inner peripheral side to the outer peripheral side of the first storage section 60.

[0110] Further, the second storage unit 62 is provided with an auxiliary partition 732. The auxiliary partition 732, the withdrawal port 100, and the suction port 102 of the second storage unit 62 are arranged so that the auxiliary partition 730, the withdrawal port 100, and the suction port 102 of the first storage unit 60 are arranged in a left-right inverted manner with respect to the first partition 720. The electrolyte solution that flows in from the withdrawal port 100 of the second storage unit 62 flows from the inner periphery side to the outer periphery side of the second storage unit 62 in that order.

[0111] 4A, the electrolyte tank 712 in Fig. 8 has a smaller flow path cross-sectional area of ​​the electrolyte flow path in each of the first storage unit 60 and the second storage unit 62. In the electrolyte tank 712 in Fig. 8, it is possible to suppress stagnation of the electrolyte in the first storage unit 60 and the second storage unit 62.

[0112] Eighth embodiment Fig. 9 is a schematic diagram of an electrolyte tank of a redox flow battery according to an eighth embodiment. Fig. 9A is a schematic horizontal cross-sectional view. Fig. 9B is a cross-sectional view taken along line IX-IX in Fig. 9A. An electrolyte tank 812 of the eighth embodiment is obtained by providing a bottom-raised portion 830 on the bottom portion 50 of the electrolyte tank 312A in Fig. 4A.

[0113] The bottom-raised portion 830 makes a part of the bottom surface portion 50 relatively higher than the other part of the bottom surface portion 50. The bottom-raised portion 830 is formed, for example, in a quadrangular pyramid shape. The bottom-raised portion 830 is provided in the center of the electrolyte tank 812 and is separated from the side surface portion 52. The center of the electrolyte tank 812 is the highest position of the bottom-raised portion 830. The first partition wall 320 is located above one diagonal line on the bottom surface of the bottom-raised portion 830. The other diagonal line on the bottom surface of the bottom-raised portion 830 extends perpendicularly from the center of the electrolyte tank 812 to the first partition wall 320. The bottom-raised portion 830 is provided so as to incline toward the bottom surface portion 50 as it proceeds from the center of the electrolyte tank 812 to the side surface portion 52. The apex of the bottom-raised portion 830 is located at a position lower than the upper limit value of the liquid level of the electrolyte.

[0114] The electrolyte solution that has flowed in from the withdrawal port 100 flows to the suction port 102 so as to avoid the bottom-raised portion 830. Therefore, in the electrolyte solution tank 812 of the eighth embodiment, the flow speed passing through a cross section that perpendicularly intersects the flow of the electrolyte solution can be made uniform within the cross section in each of the first storage section 60 and the second storage section 62. Therefore, in the electrolyte solution tank 812 of the eighth embodiment, it is possible to suppress stagnation of the electrolyte solution within the first storage section 60 and the second storage section 62.

[0115] Ninth embodiment Fig. 10 is a schematic diagram of an electrolyte tank of a redox flow battery according to the ninth embodiment. Fig. 10A is a schematic horizontal cross-sectional view. Fig. 10B is a cross-sectional view taken along line XX in Fig. 10A. The electrolyte tank 912 of the ninth embodiment is obtained by providing a bottom-raised portion 930 on the bottom portion 50 of the electrolyte tank 312A of Fig. 4A. The electrolyte tank 912 of the ninth embodiment differs from the electrolyte tank 812 of the eighth embodiment in the shape of the bottom-raised portion 930.

[0116] The raised bottom portion 930 is provided on the inside of the side portion 52 of the bottom portion 50, and is formed around the circumferential direction of the side portion 52. The raised bottom portion 930 is formed like an annular bank. The raised bottom portion 930 has the highest position at the peripheral edge portion connected to the side portion 52. The raised bottom portion 930 is provided so as to incline toward the bottom portion 50 as it proceeds from the side portion 52 toward the center of the electrolyte tank 912, and is connected to the bottom portion 50 before reaching the center of the electrolyte tank 912. The connection portion of the raised bottom portion 930 with the side portion 52 is located at a position lower than the upper limit of the height of the electrolyte liquid level.

[0117] The electrolyte solution that has flowed in from the withdrawal port 100 flows to the suction port 102 so as to avoid the bottom-raised portion 930. Therefore, in the electrolyte solution tank 912 of the ninth embodiment, the flow speed passing through a cross section that perpendicularly intersects with the flow of the electrolyte solution can be made uniform within the cross section in each of the first storage section 60 and the second storage section 62. Therefore, in the electrolyte solution tank 912 of the ninth embodiment, it is possible to suppress stagnation of the electrolyte solution within the first storage section 60 and the second storage section 62.

[0118] Tenth embodiment 11 is a schematic horizontal cross-sectional view of an electrolyte tank of a redox flow battery according to Embodiment 10. In the electrolyte tank 1012 of the tenth embodiment, an auxiliary partition wall 1030, a withdrawal port 100, and a suction port 102 are provided in the third storage section 64 of the electrolyte tank 12 of the first embodiment.

[0119] The auxiliary partition 1030 of the third storage section 64 extends in the radial direction from the intersection of the second partition 44 and the auxiliary partition 48 of the second storage section 62. The side of the auxiliary partition 1030 opposite the auxiliary partition 48 of the second storage section 62 is separated from the second partition 44. The withdrawal port 100 of the third storage section 64 is located near the auxiliary partition 1030 and the second partition 44 on one side (the right side in FIG. 11A ) separated by the auxiliary partition 1030. The suction port 102 of the third storage section 64 is located near the auxiliary partition 1030 and the second partition 44 on the other side (the left side in FIG. 11A ) separated by the auxiliary partition 1030.

[0120] 11A, in the electrolyte tank 1012 of the tenth embodiment, an electrolyte is accommodated in the first storage section 60 and the second storage section 62. The third storage section 64 does not accommodate an electrolyte and is reserved as a spare space for inspection or repair.

[0121] 11A, 11B, and 11C, in the electrolyte tank 1012 of the tenth embodiment, the spare spaces for inspection or repair are shifted in the order of the third storage section 64, the second storage section 62, and the first storage section 60. Note that the shift order is not limited to this order, and can be determined arbitrarily based on the inspection or repair schedule, etc.

[0122] 11A , when inspecting or repairing the second storage section 62, the electrolyte is discharged from the second storage section 62 and the electrolyte is accommodated in the third storage section 64. This allows the second storage section 62 to be inspected or repaired while the redox flow battery is operated by the electrolytes in the first storage section 60 and the third storage section 64.

[0123] Eleventh embodiment 12 is a schematic horizontal cross-sectional view of an electrolyte tank of a redox flow battery according to the eleventh embodiment. An electrolyte tank 1112 of the eleventh embodiment is provided with three partition walls 1120 extending radially from the center. The three partition walls 1120 are provided at intervals of 120 degrees in the circumferential direction of the electrolyte tank 1112, and divide the electrolyte tank 1112 into three in the circumferential direction. The first storage section 60, the second storage section 62, and the third storage section 64 are formed in a sector shape.

[0124] 12A, 12B, and 12C, in the electrolyte tank 1112 of the eleventh embodiment, the spare space for inspection or repair is shifted in the order of the third storage section 64, the second storage section 62, and the first storage section 60. Therefore, in the electrolyte tank 1112 of the eleventh embodiment, like the tenth embodiment, inspection or repair of the spare space can be performed while the redox flow battery is operating.

[0125] Twelfth embodiment 13 is a schematic diagram of a redox flow battery according to the twelfth embodiment. In the redox flow battery 1201 of the twelfth embodiment, a positive electrode electrolyte tank 1212A and a negative electrode electrolyte tank 1212B are provided independently. At least one of the positive electrode electrolyte tank 1212A and the negative electrode electrolyte tank 1212B is an existing fuel tank or an existing raw material tank that has been modified.

[0126] In the redox flow battery 1201 of the 12th embodiment, since there is no need to provide a partition wall separating the electrolyte of the positive electrode from the electrolyte of the negative electrode, the electrolyte tank can be configured more simply. Also, since the redox flow battery 1201 of the 12th embodiment has multiple electrolyte tanks, the battery capacity can be increased compared to the redox flow battery 1 of the first embodiment.

[0127] Thirteenth embodiment 14 is a schematic diagram of a redox flow battery 1301 according to the thirteenth embodiment. The redox flow battery 1301 according to the thirteenth embodiment is an existing underground gasoline tank converted into an electrolyte tank 1312.

[0128] The tank housing 1314 of the electrolyte tank 1312 of the thirteenth embodiment is composed of, for example, a cylindrical portion 1316 and an end surface portion 1318. The cylindrical portion 1316 is formed in a cylindrical shape with the axial direction being longer than the radial direction. Dome-shaped end surface portions 1318 are connected to both ends of the axial direction of the cylindrical portion 1316. The tank housing 1314 is formed hollow and sealed. The tank housing 1314 is buried underground with the axial direction being horizontal.

[0129] A first partition wall 1320 that divides the electrolyte tank 1312 in the axial direction is provided in the center of the electrolyte tank 1312. A first storage section 60 that accommodates a positive electrolyte is formed on one side (left side in FIG. 14) separated by the first partition wall 1320. A second storage section 62 that accommodates a negative electrolyte is formed on the other side (right side in FIG. 14) separated by the first partition wall.

[0130] In the redox flow battery 1301 of the 13th embodiment, as in the first embodiment, it is not necessary to construct an electrolyte tank from scratch, and the burden of construction labor and costs can be reduced. Therefore, in the redox flow battery 1301 of the 13th embodiment, the electrolyte tank 1312 can be easily installed.

[0131] Although the preferred embodiment of the present invention has been described above with reference to the accompanying drawings, it goes without saying that the present invention is not limited to such an embodiment. It is clear that a person skilled in the art can think of various modifications or alterations within the scope of the claims, and it is understood that these also naturally belong to the technical scope of the present invention.

[0132] For example, the features of each embodiment may be combined in any desired manner. Also, in each embodiment, the positions of the withdrawal port 100 and the suction port 102 may be reversed.

[0133] In the first, tenth and eleventh embodiments, the electrolyte tank 12 is divided into three storage sections, and in the second to ninth and thirteenth embodiments, the electrolyte tank 12 is divided into two storage sections. However, the electrolyte tank 12 may be divided into four or more storage sections. In this case, the electrolyte tank 12 may be formed with a plurality of independent first storage sections 60 and a plurality of independent second storage sections 62. That is, a plurality of pairs of the first storage section 60 and the second storage section 62 may be formed. The plurality of pairs may be associated with different cell stacks 10. [Explanation of symbols]

[0134] 1, 1201, 1301 Redox flow battery 12, 212A, 212B, 212C, 312A, 312B, 412, 512A, 512B, 512C, 612, 712, 812, 912, 1012, 1112, 1212A, 1212B, 1312 Electrolyte Tank 42, 220, 320, 420, 620, 720, 1320 1st bulkhead 44 Second bulkhead 46, 48, 222, 224, 522, 524, 532, 534, 536, 538, 730, 732, 1030 Auxiliary bulkhead 50 Bottom part 60 First storage section 62 Second Storage Unit 64 Third Storage Unit 100 Refund Port 102 Intake port 830, 930 Bottom raised part

Claims

1. The method includes a step of processing an existing fuel tank or an existing raw material tank into an electrolyte tank capable of storing an electrolyte, The electrolyte tank includes: a first partition wall provided inside the electrolyte tank and dividing the electrolyte tank into a first storage section in which an electrolyte for one of the positive electrode and the negative electrode is stored and a second storage section in which an electrolyte for the other of the positive electrode and the negative electrode is stored; an inlet provided in each of the first storage section and the second storage section for feeding an electrolyte into the electrolyte tank; an outlet provided in each of the first storage section and the second storage section, the outlet configured to deliver the electrolyte to the outside of the electrolyte tank; having The first partition is installed so as to reduce a flow path cross-sectional area of ​​a flow path of the electrolyte from the inlet to the outlet. How redox flow batteries are manufactured.

2. The method includes a step of processing an existing fuel tank or an existing raw material tank into an electrolyte tank capable of storing an electrolyte, The electrolyte tank includes: a first partition wall provided inside the electrolyte tank and dividing the electrolyte tank into a first storage section in which an electrolyte for one of the positive electrode and the negative electrode is stored and a second storage section in which an electrolyte for the other of the positive electrode and the negative electrode is stored; an inlet provided in each of the first storage section and the second storage section for feeding an electrolyte into the electrolyte tank; an outlet provided in each of the first storage section and the second storage section, the outlet configured to deliver the electrolyte to the outside of the electrolyte tank; having the first partition is installed so that a flow velocity passing through a cross section perpendicular to a flow of the electrolyte from the inlet to the outlet becomes uniform within the cross section; How redox flow batteries are manufactured.

3. 3. The method for producing a redox flow battery according to claim 1, wherein the electrolyte tank has an auxiliary partition wall that separates a part of the inside of the first storage section or the second storage section.

4. A method for manufacturing a redox flow battery described in any one of claims 1 to 3, wherein one of the inlets or the outlets is provided more than the other.

5. 5. The method for manufacturing a redox flow battery according to claim 1, wherein the first partition divides the first storage section and the second storage section into concentric circles.

6. 6. The method for manufacturing a redox flow battery according to claim 1, wherein the first partition wall is disposed so that a volume of the first container portion is equal to a volume of the second container portion.

7. 7. The method for manufacturing a redox flow battery according to claim 1, wherein the electrolyte tank has a second partition therein that separates a hollow third storage section capable of containing an electrolyte from the first storage section or the second storage section.

8. The method for manufacturing a redox flow battery according to claim 1 , wherein the electrolyte tank has a bottom-raised portion that makes a part of a bottom surface of the electrolyte tank relatively higher.

9. 9. The method for producing a redox flow battery according to any one of claims 1 to 8, wherein a volume of the electrolyte contained in the electrolyte tank is limited based on a specific gravity ratio indicating a ratio of a specific gravity of the fuel that can be contained in an original fuel tank to a specific gravity of the electrolyte contained in the electrolyte tank, or a ratio of a specific gravity of a raw material that can be contained in an original raw material tank to a specific gravity of the electrolyte contained in the electrolyte tank.

10. The electrolyte tank includes a coating material that is resistant to the electrolyte and is coated on an inner surface of the electrolyte tank; The method for producing a redox flow battery according to claim 9 , wherein the coating material is applied to a height equal to or higher than an upper limit of a liquid level in the electrolyte tank, the upper limit being determined based on the specific gravity ratio.

11. The method for producing a redox flow battery according to claim 10, wherein the coating material is coated in a detachable manner.

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