JP2013025965A - Redox flow cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a redox flow cell (RF cell) capable of reducing a leakage amount of an electrolyte in a tank.SOLUTION: An RF cell 1 charges and discharges by supplying a battery element 100c comprising a positive electrode, a negative electrode, and a diaphragm 101 with an electrolyte of tanks 106 and 107 via upstream pipes 11 and 21. Takeout ports of the electrolyte (openings 11t and 21t of the upstream pipes 11 and 21) are provided in the upper side of the tanks 106 and 107. The upstream pipes 11 and 21 are provided with low position parts 11L and 21L disposed in positions lower than the takeout ports. The tanks 106 and 107 house housing pipes 10B and 20B having leakage prevention holes 10h and 20h. The RF cell 1 is capable of reducing leakage of the electrolyte in the positive electrode tank 106 by a principle of a siphon via a reversed-u-shaped piping formed by a housing piping 10A and a part of the positive electrode upstream piping 11 at a time of an accident of the upstream piping 11 by having the small leakage prevention hole 10h disposed at the upper side of the tanks 106 and 107.

Description

  The present invention relates to a redox flow battery (hereinafter referred to as an RF battery). In particular, the present invention relates to an RF battery that can reduce the leakage of electrolyte in a tank in the event of an accident.

  In recent years, introduction of new energy such as solar power generation and wind power generation has been promoted worldwide as a countermeasure against global warming. Since these power generation outputs are affected by the weather, it is predicted that there will be a problem in the operation of the electric power system such that it becomes difficult to maintain the frequency and voltage when the mass introduction is advanced. As one of the countermeasures against this problem, it is expected to install a large-capacity storage battery to smooth the output fluctuation, save surplus power, and level the load.

  One of the large-capacity storage batteries is an RF battery. The RF battery 100 is known in the form shown in FIG. 6 (Patent Document 1, etc.). Specifically, the RF battery 100 includes a battery element 100c in which a diaphragm 101 is interposed between a positive electrode cell 102 incorporating a positive electrode 104 and a negative electrode cell 103 incorporating a negative electrode 105, and a circulation mechanism (tanks 106, 107, upstream The pipes 108 and 109, the downstream pipes 110 and 111, and the pumps 112 and 113), and using the circulation mechanism, the positive and negative electrode electrolytes are circulated and supplied to the battery element 100c for charging and discharging. As the electrolytic solution, typically, an aqueous solution containing metal ions such as vanadium ions whose valence changes by oxidation-reduction is used. In FIG. 6, the ions in the tanks 106 and 107 are illustrative. In FIG. 6, solid line arrows indicate charging, and broken line arrows indicate discharging.

  In the conventional RF battery 100, one end of the upstream pipes 108 and 109 for supplying the positive and negative electrolytes to the battery element 100c is attached to the bottom side (lower side) of the tank 106 and 107 of each electrode, and the other end is the battery element 100c. Is attached to the bottom side (lower side) (FIGS. 1 and 5 of Patent Document 1). Further, in the conventional RF battery 100, the downstream pipes 110 and 111 for returning the electrolytic solution from the battery element 100c to the tanks 106 and 107 of the respective electrodes are attached to the upper side of the tanks 106 and 107.

JP 2001-043884 A

  The conventional RF battery has a problem that when an accident such as damage to the upstream piping or the pump occurs, the electrolyte in the positive and negative tanks almost leaks.

  The electrolyte used in the RF battery is a deleterious substance such as a sulfuric acid solution, so if it leaks in large quantities, it will impair the safety of workers, affect the environment, and contaminate surrounding equipment. There is a fear. Moreover, since the said electrolyte solution has electroconductivity, there exists a possibility of making a ground fault or short-circuiting between a positive electrode cell and a negative electrode cell, or between RF battery and peripheral equipment. A similar problem can occur when one end of the downstream pipe is attached below the tank. Therefore, it is desirable to reduce the amount of the electrolyte solution leaking from the tank as much as possible even when an accident such as breakage of the piping or the pump occurs.

  Therefore, an object of the present invention is to provide a redox flow battery that can reduce the leakage of electrolyte in a tank in the event of an accident.

  In supplying the electrolytic solution in the tank to the battery element, it is conceivable to provide an outlet for the electrolytic solution in the tank, for example, on the liquid surface side of the electrolytic solution in the tank, that is, on the upper side of the tank. In this form, even if the above-mentioned accident occurs, the electrolyte solution leaking to the outside of the tank can be only the electrolyte solution located above the outlet in the electrolyte solution in the tank. That is, the leakage amount of the electrolyte in the tank can be regulated by the position of the outlet in the tank. In other words, the higher the position of the outlet from the bottom of the tank, in other words, the amount of the electrolyte in the tank. The closer to the surface, the lower the amount of electrolyte leakage from the tank.

  However, when the outlet is provided on the upper side of the tank and the downstream pipe is also attached to the upper side of the tank, the electrolytic solution returned to the tank via the downstream pipe, that is, the electrolytic solution returned to the upper side of the tank. The liquid is immediately supplied from the outlet to the battery element. Therefore, the electrolyte does not sufficiently convect in the tank, and charge / discharge is mainly performed by using a part of the electrolyte in the tank (liquid near the electrolyte surface in the tank (liquid on the upper side of the tank)). Electrolytes that are not substantially utilized in the process can be produced. A decrease in the utilization factor of the electrolytic solution leads to a decrease in battery characteristics.

  Therefore, the present inventor provided an outlet on the liquid surface side of the electrolytic solution in the tank, and arranged piping in the tank so that the electrolytic solution on the bottom side of the tank can be taken out instead of the electrolytic solution in the vicinity of the outlet. Considered to do. Here, as in the conventional redox flow battery 100 shown in FIG. 6, when a part of the upstream pipes 108 and 109 and the pumps 112 and 113 are supported on the floor surface, a support member such as a gantry can be made unnecessary, and the upstream Maintenance of the pipes 108 and 109 and the pumps 112 and 113 is easy. Then, while accommodating piping in a tank, the form which has arrange | positioned some upstream piping and a pump to the bottom part side of the electrolyte solution in a tank was examined. In this form, typically, one end of the stored pipe opens to the bottom side of the tank, a part of the upstream pipe is arranged at a position higher than the opening of the stored pipe, and the other part is in the tank. It is arrange | positioned in the position lower than the liquid level of this electrolyte solution. That is, the pipe accommodated in the tank and a part of the upstream pipe are arranged in an inverted U shape. Therefore, in this embodiment, when the above-described accident or the like occurs, the electrolyte may leak out of the tank through the inverted U-shaped portion due to the siphon principle.

  In addition, a configuration was considered in which piping arranged in the tank was connected to the downstream piping, and the electrolytic solution from the battery element was returned to the bottom side of the tank. Specifically, an electrolytic solution return port (downstream piping opening) is provided on the upper side of the tank, and a pipe stored in the tank is connected to the return port, and the stored piping is connected to the bottom side of the tank. Open. In this embodiment, when the above-described outlet is provided on the upper side of the tank, the utilization factor of the electrolyte can be increased. However, also in this embodiment, for example, when the pump or the like is supported on the floor as described above, a part of the upstream piping can be disposed at a position lower than the liquid level of the electrolytic solution in the tank. Then, the piping accommodated in the tank and a part of the upstream piping are arranged in an inverted U shape via the battery element. Therefore, in this embodiment, when the above-described accident occurs, the electrolytic solution may leak out of the tank through the inverted U-shaped portion due to the siphon principle.

  As a result of studying these points, the present invention is as follows: (1) opening the upstream pipe or downstream pipe on the liquid surface side of the electrolytic solution in the tank, (2) arranging the pipe in the tank, (3) It is proposed to open the pipe in the tank on the bottom side of the tank, connect to the upstream pipe or the downstream pipe, and (4) provide a through hole at a specific position of the pipe in the tank. .

  The redox flow battery of the present invention: the RF battery is a battery that supplies and discharges the electrolytic solution in the tank to the battery element, the upstream pipe for supplying the electrolytic solution in the tank to the battery element, and the battery The electrolytic solution in the tank is provided in a part of an electrolyte flow path composed of a downstream pipe for returning the electrolytic solution from the element to the tank, the upstream pipe, the battery element, and the downstream pipe. And a low position portion disposed at a lower position. In addition, the RF battery of the present invention includes a storage pipe disposed in the tank and connected to the upstream pipe or the downstream pipe. One end of the upstream pipe or the downstream pipe connected to one end of the storage pipe opens to a position near the liquid level of the electrolytic solution in the tank or an upper space above the liquid level. The other end of the storage pipe opens at a position near the bottom of the tank. In the storage pipe, a leakage prevention hole is provided at a position near the liquid level of the electrolytic solution in the tank. And the said leak prevention hole is smaller than the opening part of the other end side of the said storage piping.

  In the present invention, the “position near the liquid level” means that when the distance from the bottom of the tank to the liquid level of the electrolytic solution in the tank is L in a state where the above-described accident or the like has not occurred, from the bottom of the tank. (L / 2) Over L In the present invention, the “position close to the bottom” is a position of (L / 2) or less from the bottom of the tank.

  When the storage pipe is connected to the upstream pipe, the RF battery of the present invention is located near the liquid level of the electrolytic solution in the tank or above the liquid level, that is, above the tank. An outlet (opening at one end of the upstream pipe) is provided, and the electrolytic solution from the outlet is supplied to the battery element. When the storage pipe is connected to the downstream pipe, the RF battery of the present invention is provided with an electrolyte return port (an opening on one end side of the downstream pipe) on the upper side of the tank so that the electrolyte from the battery element can be removed. It is the structure which returns in the tank from the said return port. In addition, the RF battery of the present invention includes a storage pipe opened near the bottom of the tank in the tank and a low position portion disposed at a position lower than the liquid level of the electrolyte in the tank. It is. With the above configuration, the RF battery of the present invention has an upwardly convex shape (inverted U shape) that connects the storage pipe and a part of the electrolyte flow path disposed outside the tank (including the low position portion). Character shape, inverted V shape, or saddle shape). That is, the RF battery of the present invention includes an inverted U-shaped portion in the path through which the electrolytic solution is circulated.

  Therefore, the RF battery of the present invention has the above-mentioned inverted U-shaped portion in the event of an accident such as damage to the upstream pipe, downstream pipe, and the pump arranged in the upstream pipe connecting the storage pipe and the battery element. Due to the siphon principle used, the electrolyte in the tank can move to the outside of the tank via the storage pipe. However, since the RF battery of the present invention is provided with a leakage prevention hole at a position near the liquid level of the electrolytic solution in the tank in the storage pipe, that is, the upper side of the tank, the electrolytic solution leaking from the tank to the outside is provided. The amount of electrolyte present in the tank above the leakage prevention hole can be regulated. Therefore, the RF battery of the present invention can take out the electrolyte solution on the bottom side of the tank, return the electrolyte solution to the bottom side of the tank, and reduce the leakage amount of the electrolyte solution in the tank at the time of the above-mentioned accident. Can be reduced.

  In addition, since the size of the leakage prevention hole is sufficiently smaller than the opening disposed on the bottom side of the tank in the storage pipe, the RF battery of the present invention can be used when circulating the electrolyte solution to the battery element. Loss can be reduced.

  And the RF battery of the present invention has an outlet or return port for the electrolyte in the tank that opens above the tank as described above, and the other end of the storage pipe that actually sucks out the electrolyte in the tank or The other end of the storage pipe that actually discharges the electrolytic solution into the tank opens at a position near the bottom of the tank, that is, on the lower side of the tank. With this configuration, the RF battery of the present invention can use the electrolytic solution located far from the outlet and the return port in the electrolytic solution in the tank, and the utilization rate of the electrolytic solution can be increased.

  As one form of this invention, the form by which the end of the said storage piping was connected with the said upstream piping, and the said low position part was provided in a part of this upstream piping is mentioned. Alternatively, an embodiment of the present invention includes a form in which one end of the storage pipe is connected to the downstream pipe and the low position portion is provided in a part of the upstream pipe.

  Each of the above forms includes an inverted U-shaped portion formed by connecting a storage pipe and a low position part provided in the upstream pipe. However, in any form, the leakage amount of the electrolytic solution in the tank can be regulated by the leakage prevention hole as described above.

  Examples of the form in which the above-described storage pipe is connected to the upstream pipe include a form in which one end of the downstream pipe is open to a position near the liquid level of the electrolytic solution in the tank or an upper space above the liquid level. As a form in which the storage pipe is connected to the downstream pipe, one end of the upstream pipe is opened at a position near the liquid level of the electrolytic solution in the tank, or one end of the upstream pipe is in the space above the liquid level. It is open, and the form by which another storage piping opened in the electrolyte solution in the said tank was connected with this upstream piping is mentioned.

  In the former form, the electrolyte returned from the battery element to the upper side of the tank can be supplied to the battery element from the bottom side (lower side) of the tank by the storage pipe connected to the upstream pipe, and the latter form is used in the downstream form. The electrolyte returned to the bottom side (lower side) of the tank by the storage pipe connected to the pipe can be supplied to the battery element from the upper side of the tank. Therefore, in any of the above embodiments, since the electrolytic solution can be sufficiently convected in the tank, the entire electrolytic solution in the tank can be fully utilized, and the utilization rate of the electrolytic solution can be increased.

As one aspect of the present invention, when the diameter of the leakage prevention hole is φ _h and the diameter of the opening on the other end side of the storage pipe is φ _i , the diameter φ _{h of the} leakage prevention hole is 1 mm or more (φ _i The form which is less than / 2) is mentioned.

  In the above-mentioned form, the leakage prevention hole has a specific size, so that at the time of the accident described above, the leakage amount of the electrolytic solution in the tank can be regulated and the leakage amount can be reduced. The loss of the pump when supplying to the battery element can be reduced.

  The redox flow battery of the present invention can reduce the leakage amount of the electrolyte in the tank at the time of an accident or the like.

FIG. 1 is a schematic configuration diagram of a redox flow battery according to the first embodiment. FIG. 2 is a schematic configuration diagram of the redox flow battery according to the second embodiment. FIG. 3 is a schematic configuration diagram of a redox flow battery according to the third embodiment. FIG. 4 is a schematic configuration diagram of a redox flow battery according to the fourth embodiment. FIG. 5 is a schematic configuration diagram of a redox flow battery according to the fifth embodiment. FIG. 6 is an explanatory diagram showing the operating principle of the redox flow battery.

  Embodiments of the present invention will be described below with reference to the drawings. In the figure, the same reference numerals indicate the same names. The redox flow battery of the present invention: The basic configuration of the RF battery is the same as that of the conventional RF battery 100 shown in FIG. 6 described above, and the main feature is a path for circulating and supplying electrolyte solutions of positive and negative electrodes to the battery element. (Mainly piping structure). Hereinafter, only the outline of the basic configuration of the RF battery will be described, and the description will focus on the feature points.

[Overall structure]
Like the conventional RF battery 100, the RF battery of the present invention has a battery element 100c as a main constituent member, and a circulation mechanism (tanks 106, 107, piping (for details) for supplying the positive electrode electrolyte and the negative electrode electrolyte to the battery element 100c. Pumps 112 and 113), which will be described later). The RF battery of the present invention is connected to a power generation unit (e.g., a solar power generator, a wind power generator, other general power plants, etc.) and a load such as a power system or a consumer via an AC / DC converter. Connected, charging is performed using the power generation unit as a power supply source, and discharging is performed using the load as a power supply target.

[Battery element]
As the battery element 100c, a form called a cell stack in which a plurality of positive electrode cells 102, negative electrode cells 103, and a diaphragm 101 are stacked is typically used. The positive electrode cell 102 and the negative electrode cell 103 include a bipolar plate (not shown) in which the positive electrode 104 (FIG. 6) is disposed on one surface and the negative electrode 105 (FIG. 6) is disposed on the other surface, and a liquid supply hole for supplying an electrolyte solution In addition, a configuration using a cell frame having a drain hole for discharging the electrolyte and a frame (not shown) formed on the outer periphery of the bipolar plate is representative. By laminating a plurality of cell frames, the liquid supply hole and the drainage hole constitute a flow path for the electrolytic solution. The cell stack is configured by repeatedly stacking a cell frame, a positive electrode 104, a diaphragm 101, a negative electrode 105, a cell frame,.

  Typically, the positive electrode 104 and the negative electrode 105 are made of carbon felt, the diaphragm 101 is an ion exchange membrane such as a cation exchange membrane or an anion exchange membrane, the bipolar plate is made of plastic carbon, a cell frame Examples of the frame include those made of a resin such as vinyl chloride.

[Electrolyte]
The electrolyte solution for each positive and negative electrode is typically a solution containing a metal ion that becomes an active material. As a pair of metal ions used for positive and negative active materials, positive electrode: iron ion, negative electrode: chromium ion, positive electrode and negative electrode: vanadium ion, other positive electrode: manganese ion, negative electrode: titanium ion, vanadium ion, Examples thereof include at least one metal ion selected from the group consisting of chromium ions, zinc ions, and tin ions. When the positive electrode active material is manganese ions, depending on the negative electrode active material, an RF battery having an electromotive force higher than that of all vanadium-based RF batteries can be obtained. Further, when the positive electrode contains manganese ions together with manganese ions, it is possible to suppress the precipitation of MnO ₂ accompanying the disproportionation reaction of Mn ³⁺ . It can be set as the form which contains a manganese ion and a titanium ion in both a positive electrode and a negative electrode.

The electrolyte solution for each positive and negative electrode is preferably an aqueous solution containing at least one of sulfuric acid, phosphoric acid, nitric acid, sulfate, phosphate, and nitrate. In particular, those containing sulfate anions (SO ₄ ²⁻ ) are easy to use.

[Circulation mechanism]
The positive electrode electrolyte is stored in the positive electrode tank 106, and the negative electrode electrolyte is stored in the negative electrode tank 107. The tanks 106 and 107 are connected to the electrolyte flow path formed in the cell stack by a positive electrode upstream pipe 11 and a positive electrode downstream pipe 12, a negative electrode upstream pipe 21 and a negative electrode downstream pipe 22, respectively. Pumps 112 and 113 are attached to the upstream pipes 11 and 21, and the electrolyte solution in the tanks 106 and 107 is supplied to the battery element 100 c (cell stack) via the upstream pipes 11 and 21, and the tanks 106 and 107 pass through the downstream pipes 12 and 22. Return the electrolytic solution from the battery element 100c.

  The RF battery of the present invention uses the above-described circulation mechanism to pump the electrolyte solution to the battery element 100c, and charge / discharge with the valence change reaction of the metal ion that becomes the active material in the electrolyte solution of each positive and negative electrode I do.

<Embodiment 1>
A piping structure provided in the RF battery 1 of Embodiment 1 will be described with reference to FIG. In the RF battery 1, since the positive electrode side piping structure and the negative electrode side piping structure are the same, the positive electrode side piping structure will be described as an example in detail.

  One end of the positive electrode upstream pipe 11 attached to the positive electrode tank 106 and the battery element 100c and supplying the electrolytic solution in the tank 106 to the battery element 100c, that is, the opening 11t on the positive electrode tank 106 side is the electrolytic solution in the tank 106. Position close to the liquid level: It opens to a position exceeding (L / 2) (here, a position less than L from the bottom of the tank 106). The position from the bottom of the positive electrode tank 106 in the opening 11t is such that the higher the level, the easier it is to reduce the amount of electrolyte leaking from the tank 106, so that the position of (2/3) × L or more from the bottom of the tank 106, (3 / 4) × L or more is more preferable. 1 to 5, the solid lines in the positive electrode tank 106 and the negative electrode tank 107 indicate the liquid level, and the alternate long and short dash line in the tanks 106 and 107 indicates the position (L / 2).

  In the RF battery 1, the battery element 100c is supported at a position higher than the liquid level of the electrolytic solution in the positive electrode tank 106 and the negative electrode tank 107 by a mount (not shown). With this configuration, the RF battery 1 can completely extract the electrolytic solution in the battery element 100c during a period during which the charge / discharge operation is stopped. Therefore, the RF battery 1 can reduce the self-discharge due to the remaining electrolyte in the battery element 100c, and can suppress the decrease in the discharge capacity.

  In the example shown in FIG. 1, the RF battery 1 includes a low position portion 11L disposed at a position lower than the liquid level of the electrolytic solution in the positive electrode tank 106 at an intermediate portion of the positive electrode upstream pipe 11. Specifically, in the positive electrode upstream pipe 11, the opening position of one end thereof (the opening 11t on the positive electrode tank 106 side) is arranged on the liquid surface side (above the tank 106) of the electrolytic solution in the tank 106, as described above. In addition, the opening position of the other end (opening portion 11c on the battery element 100c side) is also arranged on the upper side of the tank 106 toward the battery element 100c arranged on the upper side of the tank 106. The pipe 11 is bent in a U shape so that the middle part of the positive electrode upstream pipe 11 is lower than both ends (both openings 11t and 11c), and this U-shaped portion is the low position portion 11L.

  In the example shown in FIG. 1, the pump 112 is attached to the lowest position arranged linearly in the low position portion 11L, and the linear portion and the pump 112 are the floor surface (installation surface) like the positive electrode tank 106. It is supported by. The position of the pump 112 in the longitudinal direction of the positive electrode upstream pipe 11 can be selected as appropriate, and may be a place other than the above-described position.

  One feature of the RF battery 1 is that the storage pipe 10A is disposed in the positive electrode tank 106.

  At least a part of the storage pipe 10A is immersed in the electrolytic solution in the positive electrode tank 106 (in the example shown in FIG. 1, all are immersed). Accordingly, the constituent material of the storage pipe 10A is preferably a material that does not react with the electrolyte, and examples thereof include polyvinyl chloride: PVC, polyethylene: PE, polypropylene: PP, and polytetrafluoroethylene: PTFE. This material can also be applied to the upstream pipes 11 and 21 and the downstream pipes 12 and 22.

  One end of the storage pipe 10A is connected to the opening 11t of the positive electrode upstream pipe 11 on the positive electrode tank 106 side. In other words, one end of the storage pipe 10A is opened to a position near the liquid level of the electrolyte in the positive electrode tank 106: (L / 2), and the higher the opening position is, the more preferable as described above. The storage pipe 10A and the positive electrode upstream pipe 11 may be independent pipes, and may be joined via a connecting portion, or the pipes 10A and 11 may be constituted by a single continuous pipe. This also applies to the embodiments described later.

  The other end of the storage pipe 10A is opened at a position near the bottom of the positive electrode tank 106: (L / 2). The opening position of the other end of the storage pipe 10A (positioning position of the opening 10o) is closer to the bottom of the positive electrode tank 106, and the distance from the liquid surface of the electrolytic solution in the tank 106 is larger, and the position farther from the liquid surface. Can be supplied to the battery element 100c. In particular, when the positive electrode downstream pipe 12 is open on the upper side of the positive electrode tank 106 (here, the space above the liquid level of the tank 106) as in the RF battery 1 shown in FIG. 1, the battery element 100c enters the tank 106. The returned electrolyte can be sufficiently convected until it is removed from the bottom of the tank 106. As a result, in the RF battery 1, the electrolyte in the tank 106 tends to be always in a uniform state, and this uniform electrolyte can be supplied to the battery element 100c. Therefore, the opening position of the other end of the storage pipe 10A (positioning position of the opening 10o) is preferably as the distance from the bottom of the positive electrode tank 106 is shorter (closer to the bottom), and (1/3) from the bottom of the tank 106. A position of × L or less, more preferably a position of (1/4) × L or more, particularly in the vicinity of the bottom.

  As described above, the storage pipe 10A is vertically separated from each other at its both ends. Here, the L-shape is turned upside down. In the RF battery 1, the inverted L-shaped storage pipe 10A and a part of the positive electrode upstream pipe 11 described above (the linear portion of the low position portion 11L from the opening 11t of the positive electrode upstream pipe 11 on the positive electrode tank 106 side). 1), as shown in FIG. 1, one of the features is that an inverted U-shaped pipe is formed.

  Further, the RF battery 1 is characterized in that a leakage prevention hole 10h is provided at a position near the liquid level of the electrolytic solution in the positive electrode tank 106 in the storage pipe 10A: (L / 2) less than L. . The position of the leakage prevention hole 10h is that the longer the distance from the bottom of the positive electrode tank 106 (the farther from the bottom), the more the leakage of the electrolyte in the tank 106 can be regulated. The highest position from the bottom of 106 is preferable. Here, the leakage prevention hole 10h is provided at a corner (the highest position) in the inverted L-shaped storage pipe 10A.

  The size (cross-sectional area) and cross-sectional shape of the storage pipe 10A can be selected as appropriate. Typically, the storage pipe 10A may have a uniform cross-sectional shape over the entire length. In addition, it can be set as the form which has a part from which cross-sectional shape and cross-sectional area differ in a part of longitudinal direction. Typically, the cross-sectional shape of the storage pipe 10A includes a circular shape, a rectangular shape, and the like. When the cross section is circular, the flow resistance of the electrolytic solution tends to be small. Here, the storage pipe 10A has a uniform cross-sectional shape over its entire length, and the cross-sectional shape is circular.

The size (cross-sectional area) and cross-sectional shape of the leakage preventing hole 10h can be selected as appropriate. For example, the cross-sectional shape may be a circular shape, a rectangular shape, or a non-rectangular polygonal shape or an odd shape such as an ellipse. The size (cross-sectional area) of the leakage preventing hole 10h is smaller than the size (cross-sectional area) of the opening 10o on the other end side (the bottom side of the positive electrode tank 106) of the storage pipe 10A. For example, if the cross-sectional shape of the housing pipe 10A and the leakage preventing hole 10h is circular, the diameter phi _h leakage prevention hole 10h is smaller than the diameter phi _i of the storage pipe _{10A (φ h <φ i)} . In particular, the diameter phi _h leakage prevention hole 10h is, 1 mm or more, preferably less than 1/2 of the diameter phi _i of the receiving pipe 10A, about 2mm~10mm is easy to use. Here, the cross-sectional shape of the leakage preventing hole 10h is circular shape, and the above 1mm diameter φ _h (φ _i / 2) less.

  One end of the positive electrode downstream pipe 12 opens into the space above the electrolyte in the positive electrode tank 106, and the other end is attached to the battery element 100c. The position of the opening of the downstream pipe 12 (22) can be changed as appropriate. For example, the position near the liquid surface of the electrolyte in the tank 106 and the position near the bottom of the tank 106 can be used.

  The piping structure on the negative electrode side is the same as the above-described piping structure on the positive electrode side. Specifically, one end of the negative electrode upstream pipe 21 opens at a position near the liquid level of the electrolyte in the negative electrode tank 107: (L / 2), and the other end is at the same position as the battery element 100c. It is open. Further, the negative electrode upstream pipe 21 is located between the opening 21t on the negative electrode tank 107 side and the opening 21c on the battery element 100c side (intermediate portion) at a position lower than the liquid level of the electrolyte in the negative electrode tank 107 (here, A low position portion 21L disposed at a position lower than the opening portion 21t). A pump 113 is attached to the linear portion of the low position portion 21L. In the negative electrode tank 107, an inverted L-shaped storage pipe 20A is arranged. One end of the storage pipe 20A is connected to the opening 21t of the negative electrode upstream pipe 21, and the other end (opening 20o) opens to a position near the bottom of the tank 107: (L / 2) or less. The storage pipe 20A is provided with a leakage prevention hole 20h near the one end. The inverted L-shaped storage pipe 20A and a part of the negative electrode upstream pipe 21 form an inverted U-shaped pipe. The negative electrode downstream pipe 22 opens to the upper side of the negative electrode tank 107.

  1 to 5, the opening positions of the upstream pipes 11 and 21 and the downstream pipes 12 and 22 (attachment positions of the pipes 11, 12, 12, and 22 to the tanks 106 and 107) are examples. Moreover, although each piping shown in FIGS. 1-5 is the shape bent linearly, a curved shape may be sufficient and you may arrange | position partly inclined without making it bend. Further, in FIGS. 1 to 5, the sizes of the positive and negative tanks 106 and 107 and the position of the bottom are the same, but they may be different.

(effect)
The RF battery 1 is provided with outlets (openings 11t, 21t of the upstream pipes 11, 21) for taking out the electrolyte solution in the positive electrode tank 106 and the negative electrode tank 107 near the liquid surface of the electrolyte solution, and the tanks 106, 107. The storage pipes 10A and 20A are respectively disposed in the inside, and one ends (openings 10o and 20o) thereof are opened near the bottoms of the tanks 106 and 107, respectively. With this configuration, the RF battery 1 can supply the electrolyte solution on the bottom side of the tanks 106 and 107 to the battery element 100c.

  In addition, the RF battery 1 includes an electrolyte channel outside the storage pipe 10A and the positive electrode tank 106 (here, the positive electrode upstream pipe 11), and an electrolyte solution channel outside the storage pipe 20A and the negative electrode tank 107 (here, the negative electrode upstream pipe 21). ) Are arranged in an inverted U shape, but the storage pipes 10A and 20A are respectively provided with leakage prevention holes 10h and 20h near the liquid surface of the electrolyte in the tanks 106 and 107, respectively. With this configuration, the RF battery 1 can be used in the tanks 106 and 107 even if the positive electrode upstream pipe 11, the negative electrode upstream pipe 21 and the pumps 112 and 113 are damaged or the battery element 100c and the upstream pipes 11 and 21 are disconnected. The leakage of the electrolyte can be limited to only a part of the electrolyte in the tanks 106 and 107. Specifically, of the electrolytes in the tanks 106 and 107, the electrolyte located above the leakage prevention holes 10h and 20h is reversely formed by the storage pipe 10A (20A) and a part of the upstream pipe 11 (21). The U-shaped portion can be used to leak out of the tanks 106 and 107 by the siphon principle regardless of whether the pump is driven or stopped. However, when the electrolyte solution leaks and the leakage prevention holes 10h and 20h are exposed, the inverted U-shaped portion takes in the gas phase in the tanks 106 and 107, and is not in a state filled with the electrolyte solution. The movement of the electrolyte can be automatically stopped. Therefore, the RF battery 1 can reduce the amount of electrolyte leakage in the tanks 106 and 107 when the above accident occurs.

  Further, in the RF battery 1, the opening 10o (20o) of the storage pipe 10A (20A) for supplying the electrolytic solution to the battery element 100c and the opening of the downstream pipe 12 (22) are arranged at substantially diagonal positions. Yes. Accordingly, since the amount of movement of the electrolytic solution in the positive electrode tank 106 (negative electrode tank 107) can be sufficiently secured, the RF battery 1 supplies the electrolytic solution sufficiently convected in the tank 106 (107) to the battery element 100c. It is possible to increase the utilization rate of the electrolytic solution.

[Embodiment 2]
With reference to FIG. 2, the RF battery 2 of Embodiment 2 will be described. The basic configuration of the RF battery 2 of the second embodiment is the same as that of the RF battery 1 of the first embodiment. Specifically, the RF battery 2 has a structure in which both positive and negative electrode piping structures are symmetrical, and the electrolyte solution outlets from the positive electrode tank 106 and the negative electrode tank 107 (openings 11t, 21t of the upstream pipes 11, 21). ) Is provided at a position near the liquid level of the electrolytic solution in the tanks 106 and 107. The tanks 106 and 107 include storage pipes 10B and 20B provided with leakage prevention holes 10h and 20h, respectively. In addition, the RF battery 2 includes low positions 11L and 21L in a part of the upstream pipes 11 and 21, and an inverted U-shaped pipe between the storage pipe 10B and a part of the positive electrode upstream pipe 11 (low position 11L). The storage pipe 20B and a part of the negative electrode upstream pipe 21 (low position portion 21L) form an inverted U-shaped pipe. In the RF battery 2, the shape of the storage pipes 10B and 20B is different from that of the RF battery 1 of the first embodiment. Hereinafter, this difference will be mainly described, and detailed description of configurations and effects that are the same as those of the RF battery 1 of Embodiment 1 will be omitted. Further, the second embodiment will also be described in detail by taking the positive electrode side piping structure as an example.

  In the positive electrode tank 106 included in the RF battery 2, the storage pipe 10B is stored, and one end of the storage pipe 10B opens to a position near the liquid level of the electrolytic solution in the tank 106: (L / 2), The other end opens at a position near the bottom of the tank 106: (L / 2) or less. In addition, the storage pipe 10B is provided with a small leakage prevention hole 10h at a position near the liquid level of the electrolyte in the positive electrode tank 106: (L / 2).

  In the RF battery 2 of the second embodiment, the storage pipe 10B has a convex shape, and the leakage prevention hole 10h is provided at the highest position (the apex of the convex portion) from the bottom of the positive electrode tank 106. That is, in the RF battery 2, the arrangement position of the leakage prevention hole 10h is higher than the opening 11t on the positive electrode tank 106 side of the positive electrode upstream pipe 11 that is the outlet for the positive electrode electrolyte.

  The same applies to the negative electrode side, and the storage pipe 20B has an upwardly convex shape, and the leakage prevention hole 20h is provided at the apex of the convex part, and the arrangement position of the leakage prevention hole 20h is the negative electrode tank 107 of the negative electrode upstream pipe 21. It is higher than the opening 21t on the side.

  In the RF battery 2 of the second embodiment, the amount of the electrolyte that leaks out until the leakage prevention holes 10h and 20h are exposed from the liquid level of the electrolyte in the positive electrode tank 106 and the negative electrode tank 107 in the case of the accident described above in the first embodiment. There are few compared. Therefore, the RF battery 2 can further reduce the leakage amount of the electrolytic solution in the tanks 106 and 107.

  2, the position of the opening 10o (20o) of the storage pipe 10B (20B) and the position of the opening on the positive electrode tank 106 (negative electrode tank 107) side in the downstream pipe 12 (22) are far from each other. In addition, both openings are arranged at substantially diagonal positions, and the utilization rate of the electrolytic solution is high.

[Embodiment 3]
With reference to FIG. 3, the RF battery 3 of Embodiment 3 will be described. The basic configuration of the RF battery 3 of the third embodiment is the same as that of the RF battery 1 of the first embodiment, and the positions of the openings 11t and 21t of the upstream pipes 11 and 21 serving as the outlet for the electrolyte and the storage pipe 10C. , The shape of 20C is different. Hereinafter, this difference will be mainly described, and detailed description of configurations and effects that are the same as those of the RF battery 1 of Embodiment 1 will be omitted. Further, Embodiment 3 will also be described in detail by taking the positive electrode side piping structure as an example.

  In the RF battery 3, the storage pipe 10C stored in the positive electrode tank 106 is linear, and one end of the storage battery 10C is close to the liquid level of the electrolyte in the tank 106: a position exceeding (L / 2) (here, the liquid (The upper space of the tank 106 located above the surface), and the other end is opened at a position near the bottom of the tank 106: (L / 2) or less. Further, in the storage pipe 10C, a small leakage prevention hole 10h is provided at a position near the liquid level of the electrolyte in the positive electrode tank 106: (L / 2).

  In the RF battery 3 of the third embodiment, the vicinity of the portion connected to the positive electrode tank 106 in the positive electrode upstream pipe 11 has a convex shape upward, and one end side of this convex portion is connected to the low position portion 11L. Yes. That is, in the RF battery 3, the arrangement position of the leakage prevention hole 10h is lower than the opening 11t on the positive electrode tank 106 side of the positive electrode upstream pipe 11 that is the outlet for the positive electrode electrolyte.

  The same applies to the negative electrode side, and one end of the straight storage pipe 20C is opened on the upper surface of the negative electrode tank 107, and a leakage prevention hole 20h is disposed near the liquid surface of the electrolyte in the tank 107. The part has a convex shape. The arrangement position of the leakage prevention hole 20h is lower than the opening 21t on the negative electrode tank 107 side of the negative electrode upstream pipe 21.

  In the RF battery 3 of Embodiment 3, the electrolyte outlets (openings 11t, 21t) in the positive electrode tank 106 and the negative electrode tank 107 are located above the tanks 106, 107 (here, the liquid level of the electrolyte in the tanks 106, 107). The electrolyte solution on the bottom side of the tanks 106 and 107 can be supplied to the battery element 100c. By using the storage pipes 10A to 10C and 20A to 20C in this way, the electrolyte solution in the tanks 106 and 107 is evenly distributed while the outlets for the electrolyte solution are provided at appropriate positions according to the empty space around the tanks 106 and 107. Available. Further, although the RF battery 3 has an inverted U-shaped portion formed by the storage pipes 10C and 20C and the upstream pipes 11 and 21, the RF battery 3 has the leak prevention holes 10h and 20h so that the tanks 106 and 107 The amount of leakage of the electrolyte can be reduced.

[Embodiment 4]
The RF battery 4 of Embodiment 4 will be described with reference to FIG. Similarly to the RF batteries 1 to 3 of the first to third embodiments, the RF battery 4 of the fourth embodiment also includes storage pipes 30A and 40A that open to positions near the bottoms of the positive electrode tank 106 and the negative electrode tank 107. However, the RF battery 4 of the fourth embodiment is different from the first to third embodiments in that the storage pipes 30A and 40A are connected to the positive electrode downstream pipe 12 and the negative electrode downstream pipe 22, respectively. Since the configuration other than this difference is similar to that of the third embodiment, the description of the RF battery 4 will be centered on this difference, and the configuration and effects overlapping with those of the RF battery 3 of the third embodiment will be described in detail. Omitted. Further, Embodiment 4 will also be described in detail by taking the positive electrode side piping structure as an example.

  As in the first to third embodiments, one end of the positive electrode downstream pipe 12 opens into the space above the electrolytic solution in the positive electrode tank 106, and the other end is attached to the battery element 100c. The storage pipe 30A is linear like the storage pipe 10C of the third embodiment, and one end of the storage pipe 30A is close to the liquid level of the electrolyte in the tank 106: a position exceeding (L / 2) (here, the liquid level And connected to the opening 12t of the positive electrode downstream pipe 12 disposed in the upper space of the tank 106 located above the tank 106. The other end of the storage pipe 30A opens at a position closer to the bottom of the tank 106: (L / 2) or less. In addition, a leakage prevention hole 30h smaller than the opening 30o on the other end side of the storage pipe 30A is provided at a position near the liquid level of the electrolyte in the positive electrode tank 106 in the storage pipe 30A: (L / 2). It has been.

  Similarly to the third embodiment, the positive electrode upstream pipe 11 has one end opened to the upper space of the positive electrode tank 106, the other end attached to the battery element 100c, and a low position portion 11L provided in the middle. . Further, another storage pipe 10D is connected to the opening 11t on one end side of the positive electrode upstream pipe 11. One end of the storage pipe 10D opens into the electrolyte in the tank 106. Here, the storage pipe 10D is shorter in length than the storage pipe 30A connected to the positive electrode downstream pipe 12 described above, and the opening 10o on one end side thereof is located near the liquid level of the electrolyte in the tank 106. Has been placed. Therefore, the opening 30o of the storage pipe 30A connected to the positive electrode downstream pipe 12 and the opening 10o of the short storage pipe 10D connected to the positive electrode upstream pipe 11 are substantially diagonal positions of a rectangle formed by the electrolyte. Placed in.

  The storage pipe 30A, the positive electrode downstream pipe 12, the battery element 100c, and a part of the positive electrode upstream pipe 11 (part including the low position portion 11L) are arranged in an inverted U shape.

  The piping structure on the negative electrode side is the same as the above-described piping structure on the positive electrode side, and one end of the linear storage piping 40A is connected to the opening 22t on the negative electrode tank 107 side in the negative electrode downstream piping 22. The storage pipe 40A has an opening 40o at the other end disposed at a position near the bottom of the negative electrode tank 107, and includes a small leakage prevention hole 40h at a position near the liquid surface of the electrolytic solution in the tank 107. The negative upstream pipe 21 has a short storage pipe 20D connected to an opening 21t on the tank 107 side, and the opening 20o on the other end side of the storage pipe 20D is located at a position near the liquid surface of the electrolyte in the tank 107. Is arranged. Further, the negative electrode upstream pipe 21 includes a low position portion 21L. The storage pipe 40A, the negative electrode downstream pipe 22, the battery element 100c, and a part of the negative electrode upstream pipe 21 (part including the low position portion 21L) are arranged in an inverted U shape.

  In the RF battery 4 of the fourth embodiment, the electrolyte tank outlets (openings 11t, 21t) in the positive electrode tank 106, the negative electrode tank 107, and the electrolyte solution return ports (openings 12t, 22t) from the battery element 100c. Both are provided above the tanks 106 and 107 (here, above the liquid level of the electrolytic solution in the tanks 106 and 107). However, the RF battery 4 includes the storage pipes 10D, 20D, 30A, and 40A, so that the liquid surface side electrolyte in the tanks 106 and 107 can be supplied to the battery element 100c, and the electrolyte from the battery element 100c. Can be returned to the bottom side of the tanks 106,107. The RF battery 4 is reversely formed by the storage pipes 30A, 40A and a part of the electrolyte flow path (downstream pipes 12, 22, battery element 100c, upstream pipes 11, 21) disposed outside the tanks 106, 107. Although having a U-shaped portion, the leakage prevention holes 30h and 40h can reduce the amount of electrolyte leakage in the tanks 106 and 107 in the event of the above-mentioned accident.

[Embodiment 5]
In addition, as in the RF battery 5 of the fifth embodiment shown in FIG. 5, the upstream pipe 11 (21) is positioned closer to the electrolyte surface in the positive electrode tank 106 (negative electrode tank 107) ((2 / L) And the storage pipe is not connected to the opening 11t (21t) of the upstream pipe 11 (21). This form has few storage piping, and can reduce a number of parts and an assembly process. The basic configuration of the RF battery 5 of Embodiment 5 is the same as that of the RF battery 4 of Embodiment 4 (however, the shape of the upstream pipe 11 (21) is the same as that of the RF battery 1 of Embodiment 1), Detailed description is omitted.

<Modification 1>
In any of the first to fifth embodiments described above, the configuration in which the positive and negative electrode structures are symmetrical is described. However, the electrode structures of each electrode can be different. For example, either one of the positive and negative poles does not have a storage pipe, the positive or negative pole has the pipe structure of Embodiment 1, and the other pole has the pipe structure of Embodiment 2. It can be made into a form.

<Modification 2>
In each of the first to fifth embodiments described above, the battery element 100c has been described in a form in which the battery element 100c is disposed at a position equal to or higher than the liquid level of the electrolyte in the positive electrode tank 106 and the negative electrode tank 107. Can be changed. For example, it can be configured to be disposed at the same position (floor surface or the like) as the bottoms of the bipolar tanks 106 and 107. More specifically, in the example shown in FIGS. 1 to 5, the battery element 100c is connected to the end of the straight portion where the pumps 112 and 113 are attached, of the positive electrode upstream piping 11 and the negative electrode upstream piping 12, etc. It can be. This form does not require a stand for supporting the battery element 100c.

  The present invention is not limited to the above-described embodiment, and can be appropriately changed without departing from the gist of the present invention. For example, the low position portion provided in the upstream pipe or the like only needs to be disposed at a position lower than the liquid level in the tank to which the upstream pipe or the like is connected, and it is not always necessary to have a portion disposed on the floor surface. Absent. You may arrange | position a low position part on the appropriate mount surface installed on the floor surface.

  The redox flow battery of the present invention has a large capacity for the purpose of stabilizing fluctuations in power generation output, storing electricity when surplus of generated power, load leveling, etc., for power generation of new energy such as solar power generation and wind power generation. It can utilize suitably for a storage battery. In addition, the redox flow battery of the present invention can be suitably used as a large-capacity storage battery that is installed in a general power plant or factory, for the purpose of instantaneous voltage drop / power failure countermeasures and load leveling.

1,2,3,4,5,100 Redox flow battery
10A, 10B, 10C, 10D, 30A Housing piping 10h, 30h Leakage prevention hole 10o, 30o Opening
11 Cathode upstream piping 11t, 12t Cathode tank side opening
11c Battery element side opening 11L Low position 12 Positive downstream piping
20A, 20B, 20C, 20D, 40A Housing piping 20h, 40h Leak prevention hole 20o, 40o Opening
21 Negative electrode upstream piping 21t, 22t Negative tank side opening
21c Battery element side opening 21L Low position 22 Negative electrode downstream piping
100c Battery element 101 Diaphragm 102 Positive electrode cell 103 Negative electrode cell 104 Positive electrode
105 Negative electrode 106 Positive tank 107 Negative tank 108,109 Upstream piping
110,111 Downstream piping 112,113 Pump

Claims (6)

A redox flow battery that supplies and discharges the electrolyte in the tank to the battery element,
An upstream pipe for supplying the electrolytic solution in the tank to the battery element;
Downstream piping for returning the electrolyte from the battery element to the tank;
A storage pipe disposed in the tank and connected to the upstream pipe or the downstream pipe;
A low position portion provided in a part of an electrolyte flow path constituted by the upstream pipe, the battery element, and the downstream pipe, and disposed at a position lower than a liquid level of the electrolyte in the tank. ,
One end of the upstream pipe or the downstream pipe connected to one end of the storage pipe opens to a position near the liquid level of the electrolytic solution in the tank or a space above the liquid level,
The other end of the storage pipe opens to a position near the bottom of the tank,
A leakage prevention hole is provided at a position near the liquid level of the electrolytic solution in the tank in the storage pipe,
The redox flow battery, wherein the leakage prevention hole is smaller than an opening on the other end side of the storage pipe. One end of the storage pipe is connected to the upstream pipe,
2. The redox flow battery according to claim 1, wherein the low position portion is provided in a part of the upstream pipe.   3. The redox flow battery according to claim 2, wherein one end of the downstream pipe is opened to a position near the liquid level of the electrolytic solution in the tank or to a space above the liquid level. One end of the storage pipe is connected to the downstream pipe,
2. The redox flow battery according to claim 1, wherein the low position portion is provided in a part of the upstream pipe.   One end of the upstream pipe opens to the space above the liquid level, and another storage pipe opened in the electrolytic solution in the tank is connected, or close to the liquid level of the electrolytic solution in the tank 5. The redox flow battery according to claim 4, wherein the redox flow battery is opened at a position of. When the diameter of the leakage prevention hole is φ _h and the diameter of the opening on the other end of the storage pipe is φ _i , the diameter φ _h of the leakage prevention hole is 1 mm or more and less than (φ _i / 2). The redox flow battery according to any one of claims 1 to 5, wherein

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