Redox flow battery system

Abstract

This redox flow battery system includes: a main container in which a battery cell is accommodated; and a concrete tank having a first space in which an electrolyte to be supplied to the battery cell is stored.

Description

Redox flow battery system

[0001] The present disclosure relates to a redox flow battery system. This application claims priority to Japanese Patent Application No. 2023-212140, filed December 15, 2023, the entire contents of which are incorporated herein by reference.

[0002] The redox flow battery system of Patent Document 1 includes a battery device container that houses battery cells, a positive electrode tank container that houses a positive electrode electrolyte tank that stores a positive electrode electrolyte, and a negative electrode tank container that houses a negative electrode electrolyte that stores a negative electrode electrolyte tank.

[0003] International Publication No. 2019 / 087366

[0004] The redox flow battery system of the present disclosure includes a main container that houses battery cells, and a concrete tank having a first space that stores an electrolyte solution to be supplied to the battery cells.

[0005] FIG. 1 is a partial cross-sectional view showing a redox flow battery system of Embodiment 1. FIG. 2 is a plan view showing the redox flow battery system of Embodiment 1. FIG. 3 is a cross-sectional view taken along III-III in FIG. 2. FIG. 4 is a schematic cross-sectional view showing a fixing structure between a first container and a concrete tank provided in the redox flow battery system of Embodiment 1. FIG. 5 is a plan view showing a redox flow battery system of Embodiment 2. FIG. 6 is a cross-sectional view taken along VI-VI in FIG. 5. FIG. 7 is a cross-sectional view showing a redox flow battery system of Embodiment 3. FIG. 8 is a perspective view showing a redox flow battery system of Embodiment 4. FIG. 9 is a perspective view showing a redox flow battery system of Embodiment 5. FIG. 10 is a perspective view showing a redox flow battery system of Embodiment 6. FIG. 11 is a perspective view showing a redox flow battery system of Embodiment 7.

[0006] [Problem to be Solved by the Present Disclosure] A redox flow battery system with a large battery capacity is desired. It is generally impractical to manufacture a tank with a large storage capacity in a factory and then transport the tank to the installation site. When the tank container is a typical dry container, as in Patent Document 1, the size of the tank container is limited. Therefore, to build a redox flow battery system with a large battery capacity, multiple tank containers must be transported to the installation site. However, transporting tanks with storage volumes exceeding the volume of, for example, a 40-foot container, or even a 53-foot container, is extremely difficult. Furthermore, at the installation site, the tank containers must be connected to each other by piping to achieve the desired volume. These connections are potential locations for electrolyte leakage and are structural weaknesses. Additional measures, such as the installation of dikes to prevent electrolyte leakage, are required. Furthermore, adjusting the flow of electrolyte or increasing the number of pumps may be necessary to ensure that the electrolyte flows through multiple tank containers.

[0007] An object of the present disclosure is to provide a redox flow battery system that can easily increase the battery capacity. [Effects of the Present Disclosure] The redox flow battery system of the present disclosure can easily increase the battery capacity.

[0008] <Description of Embodiments of the Present Disclosure> First, embodiments of the present disclosure will be listed and described.

[0009] (1) A redox flow battery system according to one aspect of the present disclosure includes a main container that houses battery cells, and a concrete tank having a first space that stores an electrolyte solution to be supplied to the battery cells.

[0010] The concrete tank is constructed at the installation site of the redox flow battery system. Therefore, it is not necessary to manufacture a tank for storing the electrolyte in a manufacturing factory and then transport and install it at the installation site. Therefore, the redox flow battery system of (1) above can easily increase the battery capacity. Concrete tanks are more durable than tanks made of resin or metal. Therefore, the redox flow battery system of (1) above can be used for a long period of time.

[0011] (2) The redox flow battery system according to (1) above may further include a liquid-proof structure having a dike surrounding the main container, at least a portion of which is formed by an outer wall of the concrete tank.

[0012] In the redox flow battery system of (2) above, even if the electrolyte sent from the concrete tank to the main container leaks from the main container, the leaked electrolyte can be prevented from leaking outside the embankment. In the redox flow battery system of (2) above, the outer wall of the concrete tank also serves as at least a part of the embankment, so it is easier to reduce the amount of material used to construct the embankment compared to when the outer wall of the concrete tank does not also serve as the embankment. Therefore, the redox flow battery system of (2) above makes it easier to shorten the construction period of the redox flow battery system.

[0013] (3) The redox flow battery system of (2) above may further include a first container disposed on an upper surface of a ceiling portion of the concrete tank, the first container being the main container.

[0014] The redox flow battery system of (3) above can easily reduce the installation area compared to a case in which the first container and the concrete tank are installed adjacent to each other in the horizontal direction.

[0015] (4) The redox flow battery system according to (2) above may further include a sub-container for storing an electrolyte to be supplied to the battery cells, and a first container disposed on an upper surface of a ceiling portion of the concrete tank, wherein the first container is the sub-container. The main container is disposed on an upper surface of the ceiling portion of the first container.

[0016] The redox flow battery system described above in (4) can easily reduce the installation area and increase the battery capacity.

[0017] (5) In the redox flow battery system of (3) or (4) above, the concrete tank may have a wall portion that protrudes upward from the upper surface of the ceiling portion of the concrete tank so as to surround the periphery of the first container, the liquid-proof structure may further have a base portion on which the first container is placed, the embankment portion may be the wall portion, and the base portion may be the ceiling portion of the concrete tank.

[0018] In the redox flow battery system described above in (5), even if the electrolyte sent from the concrete tank to the main container leaks from the main container, the leaked electrolyte can be prevented from flowing downward from the upper surface of the ceiling of the concrete tank.

[0019] (6) In any one of the redox flow battery systems (3) to (5) above, the concrete tank may have a fixing structure that fixes the first container to the upper surface of the ceiling portion of the concrete tank.

[0020] In the redox flow battery system described above in (6), even in the event of a natural disaster such as an earthquake or a typhoon, the first container, which is a heavy object, is unlikely to shift position on the upper surface of the ceiling of the concrete tank.

[0021] (7) In any one of the redox flow battery systems (3) to (6) above, a pump may be provided to flow the electrolyte into the battery cells, and the concrete tank may further have a second space in which the pump is housed.

[0022] The redox flow battery system of (7) above can reduce the pump head compared to when the pump is placed above the ceiling of the concrete tank. The redox flow battery system of (7) above, which can reduce the pump head, makes it easier to downsize the pump. The redox flow battery system of (7) above, which can reduce the pump head, can send electrolyte to the battery cells placed above the ceiling of the concrete tank without priming.

[0023] (8) In the redox flow battery system of (7) above, the first container may be disposed on the upper surface of the ceiling portion of the concrete tank at a location corresponding to above the second space.

[0024] In the redox flow battery system of (8), the length of the piping through which the electrolyte flows can be made shorter than when the first container is placed at a position on the upper surface of the ceiling of the concrete tank that is shifted from a position above the second space. Therefore, the redox flow battery system of (8) can reduce pressure loss in the pump. Therefore, the redox flow battery system of (8) can easily make the pump smaller.

[0025] (9) In the redox flow battery system according to any one of (3) to (8), the first container may be disposed so as to overlap a side wall portion of the concrete tank.

[0026] In the redox flow battery system described above in (9), the first container overlaps the side wall of the concrete tank when viewed from above, and therefore the first container can be supported more stably than when the first container does not overlap the side wall of the concrete tank.

[0027] (10) In the redox flow battery system according to any one of (1) to (9) above, the concrete tank may have a rib that protrudes toward the first space.

[0028] The redox flow battery system of (10) above can increase the strength of the concrete tank, and therefore can stably support the first container.

[0029] (11) In any of the redox flow battery systems (1) to (10) above, the concrete tank may have a first concrete tank and a second concrete tank that are horizontally adjacent to each other, and the side wall portion of the first concrete tank and the side wall portion of the second concrete tank may have a shared wall portion that is shared with each other.

[0030] The redox flow battery system of (11) above can reduce the amount of material used for the concrete tanks compared to when the first concrete tank and the second concrete tank are arranged horizontally in contact with each other so that the sidewalls of the first concrete tank and the second concrete tank are not shared. This makes it easier to shorten the construction period for the concrete tanks and reduce costs.

[0031] (12) In any of the redox flow battery systems (1) to (11) above, the side wall portion of the concrete tank may have an additional wall portion that is shared with the side wall portion of the additional concrete tank.

[0032] The redox flow battery system described in (12) above can be manufactured by adding a concrete tank having the same structure as an existing concrete tank to an existing concrete tank. The redox flow battery system described in (12) above can easily increase the battery capacity.

[0033] (13) In the redox flow battery system described above in (2), the main container and the concrete tank may be arranged with a gap between them in the horizontal direction.

[0034] The redox flow battery system (13) above has a high degree of freedom in terms of the layout of the main container and the concrete tank.

[0035] (14) In the redox flow battery system of (13) above, the embankment may include a side wall of the concrete tank.

[0036] In the redox flow battery system described above in (14), the side wall of the concrete tank also serves as the embankment, making it easier to reduce the amount of material used to construct the embankment compared to when the side wall of the concrete tank does not also serve as the embankment.

[0037] (15) In the redox flow battery system of (14) above, the concrete tank may have a first concrete tank and a second concrete tank arranged horizontally at a distance from each other to sandwich the main container, the liquid-proof structure may further have a base portion on which the main container is arranged, the embankment portion may have a first outer wall portion of the first concrete tank, a second outer wall portion of the second concrete tank, and a first connecting wall portion and a second connecting wall portion connecting the first outer wall portion and the second outer wall portion to sandwich the main container, and the base portion may be surrounded by the first outer wall portion, the second outer wall portion, the first connecting wall portion, and the second connecting wall portion.

[0038] The redox flow battery system of (15) above has a higher degree of freedom in the placement of the main container and the concrete tank compared to when the main container is placed on the upper surface of the ceiling of the concrete tank.

[0039] (16) The redox flow battery system according to (15) above may further include a sub-container that stores an electrolyte solution to be supplied to the battery cells, and the sub-container may be disposed inside the dike portion.

[0040] The redox flow battery system of (16) above can increase the battery capacity. <<Details of the Embodiments of the Present Disclosure>> Specific examples of the redox flow battery system of the present disclosure will now be described with reference to the drawings. The same reference numerals in the figures indicate the same objects. The shapes, sizes, and positional relationships shown in the figures are depicted for the purpose of clarifying the description and do not necessarily represent the actual shapes, sizes, and positional relationships. The same reference numerals in the figures indicate the same objects. The present invention is not limited to the configurations shown in the embodiments, but is defined by the claims, and all modifications within the meaning and scope of the claims are intended to be included.

[0041] <<Embodiment 1>> [Redox Flow Battery System] A redox flow battery system 1 of Embodiment 1 will be described with reference to Figures 1 to 4. As shown in Figure 1, the redox flow battery system 1 includes battery cells 10. The battery cells 10 are charged and discharged. An electrolyte 9 is supplied to the battery cells 10. One of the features of the redox flow battery system 1 of Embodiment 1 is that it includes a main container 2 that houses the battery cells 10 and a concrete tank 3 having a first space 33 that stores the electrolyte 9 to be supplied to the battery cells 10. For ease of explanation, in Figures 1 to 3, the center line of the thickness of a side wall portion 36 that separates adjacent first spaces 33 is shown by a two-dot chain line. In Figure 2, for ease of explanation, the inner contour line of the side wall portion 36 of the concrete tank 3 is shown by a dashed line.

[0042] [Main Container] Battery cells 10 are housed inside the main container 2. The battery cells 10 are well-known battery cells. The battery cells 10 are usually formed inside a structure called a cell stack 100. That is, the cell stack 100 is housed inside the main container 2. The cell stack 100 includes a plurality of stacked battery cells 10. The cell stack 100 is a well-known cell stack. For ease of explanation, the battery cells 10 and the cell stack 100 are omitted from Figures 2 and 3. The battery cells 10 and the cell stack 100 are also omitted from Figures 5 to 11, which will be referenced in other embodiments described later.

[0043] In this example, although not shown, a supply pipe that supplies the electrolyte 9 to the battery cells 10 and a discharge pipe that discharges the electrolyte 9 from the battery cells 10 are also arranged inside the main container 2. A first end of the supply pipe is connected to a forward pipe (described later), and a second end of the supply pipe is connected to the battery cells 10. A first end of the discharge pipe is connected to the battery cells 10, and a second end of the discharge pipe is connected to a return pipe (described later). For example, a through-hole is provided in the bottom 21 of the main container 2 through which the supply pipe and the discharge pipe pass. A pump 6 ( FIG. 3 ) that circulates the electrolyte 9 to the battery cells 10 is connected to the supply pipe. In this example, the pump 6 is not arranged inside the main container 2. Unlike this example, the pump 6 may be arranged inside the main container 2. Although not shown, a control device that controls the operation of the pump 6 may be arranged inside the main container 2. The control device is, for example, a computer.

[0044] The main container 2 is typically shaped like a rectangular parallelepiped. The main container 2 includes a rectangular bottom 21 that is installed on the installation target, a rectangular ceiling 22 that faces the bottom 21, two first side walls 23 that connect the long sides of the bottom 21 and the ceiling 22, and two second side walls 24 ( FIG. 2 ) that connect the short sides of the bottom 21 and the ceiling 22. Although not shown, at least one of the two first side walls 23 and the two second side walls 24 is provided with a door that can be opened and closed freely to allow workers to access the inside of the main container 2. The main container 2 is made of, for example, steel. An example of steel is general structural rolled steel SS400.

[0045] The size of the main container 2 can be selected appropriately depending on the battery output of the redox flow battery system 1, etc. The larger the main container 2, the greater the number of battery cells 10 that can be accommodated in the main container 2, resulting in a redox flow battery system 1 with higher battery output. The main container 2 is, for example, a dry container. A dry container is, for example, an international maritime cargo container that complies with the ISO standard ISO 1496-1:2013. The main container 2 is typically a 20-foot container, a 40-foot container, a 45-foot container, a 53-foot container, or a taller container such as a 20-foot high cube container, a 40-foot high cube container, a 45-foot high cube container, or a 53-foot high cube container. The size of the main container 2 is not limited to the above.

[0046] The main container 2 has a bottom 21, a ceiling 22, side walls 23 and 24, and a door, and need only be a housing with a capacity large enough to store a predetermined number of battery cells 10; it does not have to be an international maritime container. For example, the main container 2 may be a housing assembled from a rectangular parallelepiped outer frame that surrounds the stored items, such as the battery cells 10, and a top panel, floor panel, and side wall panels attached to the outer frame. Furthermore, the main container 2 may be equipped with shelves so that the stored items, such as the battery cells, can be positioned in predetermined positions within the main container. The stored items may be fixed to the outer frame or shelves. If the main container 2 has an outer frame, the weight of the stored items can also be supported by the outer frame by fixing shelves to the members that make up the outer frame.

[0047] The number of main containers 2 is not particularly limited and can be appropriately selected depending on the required battery output. In Fig. 2, an example of the redox flow battery system 1 including four main containers 2 is shown.

[0048] [Concrete Tank] The concrete tank 3 has an internal space in which the electrolyte 9 is stored. For ease of explanation, the electrolyte 9 is omitted from FIG. 2 . As shown in FIG. 2 , the concrete tank 3 has an inner wall portion 362 that divides the internal space into multiple first spaces 33. The inner surface of the concrete tank 3 has multiple first inner surfaces 331. Each first inner surface 331 constitutes a first space 33. The electrolyte 9 stored in one first space 33 is either a cathode electrolyte supplied to the cathode cell of the battery cell 10 or a cathode electrolyte supplied to the anode cell of the battery cell 10. The cathode electrolyte and the anode electrolyte are known cathode electrolyte and anode electrolyte. A coating layer made of an electrically insulating material, such as a resin, that is resistant to the electrolyte may be provided on a portion of each first inner surface 331 that comes into contact with the electrolyte. The number and size of each first space 33 are not particularly limited and can be selected appropriately depending on the required battery capacity. The concrete tank 3 in this example has eight first spaces 33 .

[0049] The concrete tank 3 is constructed at the installation site of the redox flow battery system 1. Therefore, it is not necessary to manufacture a tank for storing the electrolyte 9 in a manufacturing factory and then transport and install it at the installation site. Therefore, the redox flow battery system 1 can easily increase the battery capacity. The concrete tank 3 is more durable than tanks made of resin or metal. Therefore, the redox flow battery system 1 can be used for a long period of time. The concrete tank 3 is less likely to leak the electrolyte 9. The concrete tank 3 is a tank made of, for example, reinforced concrete.

[0050] There are no particular limitations on the shape of the concrete tank 3. In this example, the concrete tank 3 is shaped like a rectangular parallelepiped. The concrete tank 3 in this example includes a rectangular bottom portion that is installed on the installation target, a rectangular ceiling portion 35 that is arranged opposite the bottom portion, and sidewall portions 36 that connect the bottom portion and the ceiling portion 35.

[0051] Although not shown, the ceiling portion 35 is provided with a door that can be opened and closed to allow workers to access the interior of the concrete tank 3. The side wall portion 36 has an outer wall portion 361 and an inner wall portion 362. The outer wall portion 361 connects the outer peripheral edge of the bottom portion to the outer peripheral edge of the ceiling portion 35. The inner wall portion 362 divides the internal space surrounded by the bottom portion, the ceiling portion 35, and the outer wall portion 361 into multiple first spaces 33. The inner wall portion 362 connects a portion inside the outer peripheral edge of the bottom portion to a portion inside the outer peripheral edge of the ceiling portion 35 to the outer wall portion 361. In this example, the inner wall portion 362 divides the internal space into eight first spaces 33. The outer wall portion 361 has an outer surface facing the outside of the concrete tank 3 and an inner surface facing the electrolyte 9 stored inside each first space 33. The inner wall portion 362 has an inner surface facing the electrolytic solution 9 stored inside one of the adjacent first spaces 33, and an inner surface facing the electrolytic solution 9 stored inside the other first space 33. These inner surfaces are part of the first inner surface 331.

[0052] Pressure acts on the inner wall 362 by the electrolyte 9 stored in the adjacent first spaces 33 sandwiching the inner wall 362. This pressure helps the inner wall 362 maintain the strength required to stay upright from the bottom. Therefore, the thickness of the inner wall 362 can be reduced. Therefore, the redox flow battery system 1 can reduce the amount of material used for the concrete tank 3. Because the thickness of the inner wall 362 can be reduced, the installation area of ​​the concrete tank 3 can be reduced when the volume of each first space 33 is constant. Because the thickness of the inner wall 362 can be reduced, the volume of each first space 33 can be increased when the installation area of ​​the concrete tank 3 is constant.

[0053] The concrete tank 3 in this example has a first concrete tank 31 and a second concrete tank 32 adjacent to each other in the horizontal direction. The number of first concrete tanks 31 and second concrete tanks 32 is not particularly limited and can be selected appropriately depending on the required battery capacity. In FIG. 2 , an example is shown in which the concrete tank 3 has two first concrete tanks 31a, 31b and two second concrete tanks 32a, 32b. In FIG. 2 , the first concrete tanks 31a, 31b are arranged at the lower right and upper left of the page, and the second concrete tanks 32a, 32b are arranged at the lower left and upper right of the page. Each of the first concrete tanks 31a, 31b and each of the second concrete tanks 32a, 32b has a first space 33a, 33b aligned vertically on the page. A cathode electrolyte is stored in the first space 33a of each of the first concrete tanks 31a, 31b and each of the second concrete tanks 32a, 32b, and an anode electrolyte is stored in the first space 33b. The cathode electrolyte and the anode electrolyte stored in each of the first concrete tanks 31a, 31b are supplied to the battery cells inside the main container 2 arranged on the ceiling portion 35 of each of the first concrete tanks 31a, 31b. The cathode electrolyte and the anode electrolyte stored in each of the second concrete tanks 32a, 32b are supplied to the battery cells inside the main container 2 arranged on the ceiling portion 35 of each of the second concrete tanks 32a, 32b. The concrete tank 3 of this example is configured by adding two second concrete tanks 32a, 32b and one first concrete tank 31b to the existing first concrete tank 31a.

[0054] The inner wall portion 362 of the concrete tank 3 is a shared wall portion 38a that is shared with the adjacent first spaces 33 as the side wall portion 36. The thickness of the shared wall portion 38a is thinner than the thickness of the non-shared outer wall portion 361. Among the shared wall portions 38a, the following shared wall portions 38a are expansion wall portions 38b: The shared wall portion 38a between the first concrete tank 31a and the second concrete tank 32a The shared wall portion 38a between the first concrete tank 31a and the second concrete tank 32b A portion of the expansion wall portion 38b is the outer wall portion 361 of the first concrete tank 31a before expansion. During expansion, the inner wall portion 362 may be subjected to necessary treatment when using the outer wall portion 361 as the expansion wall portion 38b. Such treatment may include, for example, polishing the outer wall portion 361 and forming the coating layer. The above process allows the thickness of the extension wall portion 38 b to be thinner than the thickness of the outer wall portion 361 .

[0055] In this example, the contour shape of each first space 33 as viewed from above is rectangular. In this example, the contour shape of the side wall portions 36 constituting each first space 33 as viewed from above is also rectangular. The contour shape of the first space 33 as viewed from above and the shape of the side wall portions 36 constituting each first space 33 as viewed from above may be similar. For example, the contour shape of the side wall portions 36 constituting the first space 33a of the first concrete tank 31a as viewed from above is a shape bounded by the contour line of the long outer wall portion 361, the contour line of the short outer wall portion 361, the center line of the thickness of the long inner wall portion 362, and the center line of the thickness of the short inner wall portion 362, as shown below. The long outer wall portion 361 is the outer wall portion 361 located below the first space 33 at the lower right of the drawing and extending in the left-right direction of the drawing. The short outer wall portion 361 is the outer wall portion 361 located to the right of the first space 33 at the bottom right of the page and extending in the vertical direction of the page. The long inner wall portion 362 is the inner wall portion 362 that separates the first space 33a of the first concrete tank 31a from the first space 33b of the second concrete tank 32a.

[0056] As shown in Fig. 3 , the concrete tank 3 of this example has ribs 39 that protrude toward each first space 33. Providing the ribs 39 tends to increase the strength of the concrete tank 3. The ribs 39 of this example are provided on the ceiling portion 35 so as to protrude from the lower surface of the ceiling portion 35 toward the bottom of the concrete tank 3. The number and locations of the ribs 39 are not particularly limited and can be selected appropriately. The ribs 39 may be provided on the lower surface of the ceiling portion 35 at a location corresponding to the lower side of the main container 2. In particular, the ribs 39 may be provided on the lower surface of the ceiling portion 35 at a location corresponding to the lower side of the first side wall portion 23 of the main container 2.

[0057] Although not shown, inside the concrete tank 3 of this example, there are arranged outgoing pipes that send the electrolyte 9 in each first space 33 to the above-mentioned supply pipe, and return pipes that return the electrolyte 9 that has passed through the discharge pipe to each first space 33. For example, the ceiling portion 35 of the concrete tank 3 is provided with through holes through which the outgoing pipes and return pipes pass.

[0058] As shown in FIG. 3 , the concrete tank 3 of this example further includes second spaces 34 that house pumps 6 that circulate the electrolyte 9 inside each first space 33 to the battery cells 10. For ease of explanation, FIG. 3 shows only the concrete tank 3 in cross section. The inner surface of the concrete tank 3 includes second inner surfaces 341 that define the second spaces 34. The number of second spaces 34 is the same as the number of pumps 6, which in this example is the same as the number of first spaces 33. The concrete tank 3 of this example has eight second spaces 34. Each second space 34 is adjacent to a corresponding first space 33. Each first space 33 and each second space 34 are separated by a partition 37. The location of each second space 34 is not particularly limited and can be selected as appropriate. As shown in Figure 3, in the first concrete tank 31a and the second concrete tank 32a, each second space 34 is provided at the corner between the inner wall portion 362 and the ceiling portion 35 between the first concrete tank 31a and the second concrete tank 32a.

[0059] [Arrangement] In this example, as shown in Figure 2, each main container 2 is arranged on the upper surface of the ceiling 35 of each first concrete tank 31 or each second concrete tank 32 so that the direction along the longitudinal direction of each main container 2 is perpendicular to the longitudinal direction of each first concrete tank 31 or each second concrete tank 32. As shown in Figure 3, each main container 2 is arranged in a location on the upper surface of the ceiling 35 of the concrete tank 3 that corresponds to above the second space 34. As shown in Figures 2 and 3, each main container 2 is arranged so as to overlap the upper part of at least one of the side wall part 36 and the rib 39. In this example, each main container 2 is arranged so as to overlap the upper part of both the side wall part 36 and the rib 39. 2 and 3, one first side wall portion 23 of each main container 2 overlaps the upper part of the inner wall portion 362 between the first concrete tank 31 and the second concrete tank 32 that are aligned horizontally on the page, and as shown in Fig. 3, the other first side wall portion 23 overlaps the upper part of the rib 39. One second side wall portion 24 of each main container 2 overlaps the upper part of the outer wall portion 361, and the other second side wall portion 24 overlaps the upper part of the inner wall portion 362 between the first concrete tank 31 and the second concrete tank 32 that are aligned vertically on the page.

[0060] Unlike this example, each main container 2 may be disposed on the upper surface of the ceiling portion 35 of each first concrete tank 31 or each second concrete tank 32 so that the direction along the length of each main container 2 is aligned with the direction along the length of each first concrete tank 31 or each second concrete tank 32. In this case, for example, each main container 2 may be disposed so that the midpoint of each second side wall portion 24 overlaps the upper portion of the inner wall portion 362 between the first spaces 33 of each first concrete tank 31 or each second concrete tank 32.

[0061] As shown in FIG. 4 , the concrete tank 3 of this example may include a securing structure 7 that secures each main container 2 to the upper surface of the ceiling 35 of the concrete tank 3. This securing structure 7 refers to a structure that restricts movement of each main container 2 at least along the upper surface of the ceiling 35. In addition to restricting movement along the upper surface of each main container 2, the securing structure 7 may also restrict movement of each main container 2 upward from the upper surface of the ceiling 35. The securing structure 7 is not particularly limited as long as it can secure each main container 2 to the concrete tank 3 and can be selected appropriately. For example, the securing structure 7 may be formed of a protrusion 35b that fits into a recess 211 provided in the bottom 21 of each main container 2. Unlike this example, the securing structure 7 may be a twist lock, which is used to secure dry containers. Because each main container 2 has an engaging portion that engages with a twist lock, if the securing structure 7 is a twist lock, there is no need to newly modify the structure of each main container 2. The number and installation locations of the securing structures 7 are not particularly limited and can be selected appropriately.

[0062] <<Embodiment 2>> A redox flow battery system 1 of Embodiment 2 will be described with reference to Figures 5 and 6. The redox flow battery system 1 of Embodiment 2 differs from the redox flow battery system 1 of Embodiment 1 in that it further includes a liquid-proof structure 4. The following description will focus on the differences from Embodiment 1. Description of configurations and effects similar to those of Embodiment 1 may be omitted. For ease of description, Figures 5 and 6 only show the first concrete tank 31a in Figure 2 as the concrete tank 3. For ease of description, Figure 6 only shows a cross section of the embankment 42 provided in the liquid-proof structure 4.

[0063] [Liquid-Proof Structure] The liquid-proof structure 4 includes a base portion 41 on which the main container 2 is disposed and an embankment portion 42 surrounding the main container 2. Even if the electrolyte 9 leaks from the main container 2, the liquid-proof structure 4 can contain the leaked electrolyte 9 inside the liquid-proof structure 4. This prevents the leaked electrolyte 9 from spreading outside the embankment portion 42. The embankment portion 42 is configured to protrude upward from the upper surface of the base portion 41. The height of the embankment portion 42 and the size of the area enclosed by the embankment portion 42 can be appropriately selected depending on the maximum amount of electrolyte 9 that may leak. This maximum amount is, for example, the amount of electrolyte 9 contained in all piping, the cell stack 100, and all circulation system equipment, such as the pump 6, inside the main container 2. At least a portion of the embankment portion 42 is formed by the outer wall of the concrete tank 3. The outer wall is a wall having an exterior surface, such as the ceiling portion 35 and the outer wall portion 361.

[0064] In this example, the base portion 41 is a part of the ceiling portion 35 of the concrete tank 3. In this example, the embankment portion 42 is the wall portion 35a of the concrete tank 3. The wall portion 35a is configured to protrude upward from the upper surface of the ceiling portion 35 of the concrete tank 3 so as to surround the periphery of the main container 2. This prevents leaked electrolyte 9 from flowing downward from the upper surface of the ceiling portion 35. In this example, the wall portion 35a has a rectangular frame shape when viewed from above. In this example, the wall portion 35a is configured with a first wall portion 351 and a second wall portion 352 along the second side wall portion 24 of the main container 2, and a third wall portion 353 and a fourth wall portion 354 along the first side wall portion 23 of the main container 2.

[0065] As shown in FIG. 5 , the positions of the first wall portion 351, the second wall portion 352, the third wall portion 353, and the fourth wall portion 354 when viewed from above are as follows: The first wall portion 351 is located near the long outer wall portion 361 at the bottom of the page, or at a location overlapping the upper part of the long outer wall portion 361. The second wall portion 352 is located near the inner wall portion 362 between the first concrete tank 31 a and the second concrete tank 32 b shown in FIG. 2, or at a location overlapping the upper part of the inner wall portion 362. The third wall portion 353 is located near the inner wall portion 362 between the first concrete tank 31 a and the second concrete tank 32 a shown in FIG. 2, or at a location overlapping the inner wall portion 362. The fourth wall portion 354 is located midway between the first side wall portion 23 on the right side of the page and the short outer wall portion 361 on the right side of the page. Unlike this example, the fourth wall portion 354 may be provided at a location closer to the first side wall portion 23 than the intermediate portion. Unlike this example, the fourth wall portion 354 may be provided at a location closer to the short outer wall portion 361 than the intermediate portion, or at a location overlapping the upper portion of the short outer wall portion 361.

[0066] <<Embodiment 3>> A redox flow battery system 1 of Embodiment 3 will be described with reference to Figure 7. The redox flow battery system 1 of Embodiment 3 differs from the redox flow battery system 1 of Embodiment 2 in that it further includes a sub-container 5. The following description will focus on the differences from Embodiment 2. Description of configurations and effects similar to those of Embodiment 2 may be omitted. Figure 7 shows the redox flow battery system 1 cut at the same position as Figure 6. As with Figure 6, for convenience of description, Figure 7 shows only the dike portion 42 provided in the liquid-proof structure 4 in cross section.

[0067] [Sub-container] The sub-container 5 stores the electrolyte to be supplied to the battery cells inside the main container 2. The sub-container 5 has a coating layer that coats the inner surface of the sub-container 5. This coating layer is made of an electrically insulating material that is resistant to the electrolyte, such as a resin. For the shape, material, and size of the sub-container 5, please refer to the description of the main container 2. The sub-container 5 may be a container for international marine cargo. The sub-container 5 is placed on the upper surface of the ceiling portion 35 of the concrete tank 3. The main container 2 is placed on the upper surface of the ceiling portion 55 of the sub-container 5.

[0068] Although not shown, the concrete tank 3 is provided with a fixing structure. This fixing structure fixes the sub-container 5 to the upper surface of the ceiling 35 of the concrete tank 3. This fixing structure may be formed of a protrusion into which a recess provided in the bottom of the sub-container 5 is fitted, similar to the fixing structure 7 of the first embodiment described with reference to Figure 4. This fixing structure may be a twist lock. The sub-container 5 may also be provided with a fixing structure that fixes the main container 2 to the upper surface of the ceiling 55 of the sub-container 5. The fixing structure of the sub-container 5 is similar to the fixing structure of the concrete tank 3.

[0069] In the redox flow battery system 1 of embodiment 3, the amount of electrolyte stored can be easily increased by transporting the sub-container 5. Because the sub-container 5 is located below the main container 2, leaked liquid from the concrete tank 3 and sub-container 5 does not come into contact with the main container 2, particularly the battery cells 10. The height of the dike 42 of the liquid-proof structure 4 can be increased depending on the amount of electrolyte stored in the sub-container 5. This height adjustment prevents leaked electrolyte 9 from spreading outside the dike 42, even when the sub-container 5 is provided.

[0070] Fourth Embodiment A redox flow battery system 1 of a fourth embodiment will be described with reference to Fig. 8. The redox flow battery system 1 of the fourth embodiment differs from the redox flow battery system 1 of the first embodiment in that the main container 2 and the concrete tank 3 are arranged with a gap between them in the horizontal direction and in that the redox flow battery system 1 of the fourth embodiment further includes a liquid-proof structure 4. The following description will focus on the differences from the first embodiment. Descriptions of the same configurations and effects as those of the first embodiment may be omitted.

[0071] [Concrete Tank] The concrete tank 3 has a first concrete tank 31 and a second concrete tank 32 that are arranged horizontally at a distance from each other and sandwich the main container 2. Therefore, it is not necessary to stack the main container 2 on the ceiling 35 of the concrete tank 3. In this example, the first concrete tank 31 and the second concrete tank 32 are arranged so that the longitudinal directions of the first concrete tank 31 and the second concrete tank 32 are parallel to each other. The first concrete tank 31, the second concrete tank 32, and the main container 2 are arranged so that the longitudinal directions of each of them are parallel to each other. Although not shown in the figure, the first concrete tank 31 and the second concrete tank 32 each have one first space. In this example, a positive electrode electrolyte is stored in the first space of the first concrete tank 31, and a negative electrode electrolyte is stored in the first space of the second concrete tank 32.

[0072] [Liquid-proof Structure] The embankment 42 of the liquid-proof structure 4 has a first outer wall 361a of the first concrete tank 31, a second outer wall 361b of the second concrete tank 32, a first connecting wall 43, and a second connecting wall 44. The first outer wall 361a is a part of the outer wall 361 of the first concrete tank 31. The second outer wall 361b is a part of the outer wall 361 of the second concrete tank 32. The first connecting wall 43 and the second connecting wall 44 connect the first outer wall 361a and the second outer wall 361b so as to sandwich the main container 2. In this example, the first connecting wall 43 is connected to first ends of the first outer wall 361a and the second outer wall 361b in the longitudinal direction. In this example, the second connecting wall 44 is connected to second ends of the first outer wall 361a and the second outer wall 361b in the longitudinal direction. The first connecting wall 43 and the second connecting wall 44 are configured to protrude upward from the upper surface of the base 41 of the liquidproof structure 4. The height of the first connecting wall 43 and the second connecting wall 44 and the size of the area surrounded by the embankment 42 can be appropriately selected depending on the maximum amount of leaked electrolyte 9. The base 41 of the liquidproof structure 4 is surrounded by the first outer wall 361a, the second outer wall 361b, the first connecting wall 43, and the second connecting wall 44. The base 41, the first connecting wall 43, and the second connecting wall 44 are concrete structures integrated with the first concrete tank 31 and the second concrete tank 32 using the same concrete as the first concrete tank 31 and the second concrete tank 32.

[0073] In the redox flow battery system 1 of Embodiment 4, the area of ​​the outer wall portion 361 used in the liquid-proof structure 4 is larger than in Embodiments 2 and 3. Therefore, the amount of concrete used in the embankment portion 42 tends to be smaller.

[0074] Fifth Embodiment A redox flow battery system 1 of a fifth embodiment will be described with reference to Fig. 9. The redox flow battery system 1 of the fifth embodiment differs from the redox flow battery system 1 of the fourth embodiment in that it further includes a sub-container 5 disposed inside the dike portion 42. The following description will focus on the differences from the fourth embodiment. Descriptions of configurations and effects similar to those of the fourth embodiment may be omitted.

[0075] [Sub-container / Main container] The sub-container 5 is disposed on the upper surface of the base portion 41 of the liquid-proof structure 4. The main container 2 is disposed on the upper surface of the ceiling portion 55 of the sub-container 5. Therefore, in the redox flow battery system 1 of embodiment 5, similar to embodiment 3, leakage liquid from the concrete tank 3 and the sub-container 5 does not come into contact with the main container 2, particularly the battery cells 10. Unlike this example, the main container 2 and the sub-container 5 may be disposed side-by-side on the upper surface of the base portion 41.

[0076] Sixth Embodiment A redox flow battery system 1 of Sixth Embodiment will be described with reference to Fig. 10 . Similar to the redox flow battery system 1 of Fourth Embodiment, the redox flow battery system 1 of Sixth Embodiment has a concrete tank 3 including a first concrete tank 31 and a second concrete tank 32. The redox flow battery system 1 of Sixth Embodiment differs from the redox flow battery system 1 of Fourth Embodiment in that a portion of the first concrete tank 31 and a portion of the second concrete tank 32 are arranged so as to be in contact with each other in the horizontal direction. The following description will focus on the differences from Fourth Embodiment. Descriptions of the same configurations and effects as those of Fourth Embodiment may be omitted.

[0077] The first concrete tank 31 and the second concrete tank 32 are arranged so that the longitudinal direction of the first concrete tank 31 is perpendicular to the longitudinal direction of the second concrete tank 32. A corner of a first end portion of the first concrete tank 31 in the longitudinal direction is connected to a corner of a first end portion of the second concrete tank 32 in the longitudinal direction. The first outer wall portion 361a of the first concrete tank 31 and the second outer wall portion 361b of the second concrete tank 32 are connected continuously in an L-shape. The main container 2 in this example is arranged so that the longitudinal direction of the main container 2 is parallel to the longitudinal direction of the first concrete tank 31.

[0078] The embankment 42 of the liquid-proof structure 4 is composed of a first outer wall 361a of the first concrete tank 31, a second outer wall 361b of the second concrete tank 32, and an L-shaped first connecting wall 43. A first end of the first connecting wall 43 is connected to the end of the first outer wall 361a that is far from the second concrete tank 32. A second end of the first connecting wall 43 is connected to the end of the second outer wall 361b that is far from the first concrete tank 31.

[0079] Seventh Embodiment A redox flow battery system 1 of Seventh Embodiment will be described with reference to Fig. 11 . The redox flow battery system 1 of Seventh Embodiment differs from the redox flow battery system 1 of Sixth Embodiment in the arrangement of the first concrete tank 31 and the second concrete tank 32. The following description will focus on the differences from Sixth Embodiment. Description of configurations and effects similar to those of Sixth Embodiment may be omitted. In Fig. 11 , the center line of the thickness of the side wall portion 36 that partitions adjacent first spaces is indicated by a two-dot chain line.

[0080] The first concrete tank 31 and the second concrete tank 32 are arranged adjacent to each other so that the longitudinal direction of the first concrete tank 31 and the longitudinal direction of the second concrete tank 32 are aligned in the same straight line. A shared wall portion is arranged between the first concrete tank 31 and the second concrete tank 32. The outer surface of the first outer wall portion 361a of the first concrete tank 31 and the outer surface of the second outer wall portion 361b of the second concrete tank 32 are connected in series to form the same plane.

[0081] The embankment 42 of the liquid-proof structure 4 is composed of a first outer wall 361a of the first concrete tank 31, a second outer wall 361b of the second concrete tank 32, and a U-shaped first connecting wall 43. A first end of the first connecting wall 43 is connected to the end of the first outer wall 361a that is far from the second concrete tank 32. A second end of the first connecting wall 43 is connected to the end of the second outer wall 361b that is far from the first concrete tank 31.

[0082] Eighth Embodiment Although not shown in the drawings, a redox flow battery system according to an eighth embodiment may further include the sub-container 5 described in the fifth embodiment in the sixth or seventh embodiment.

[0083] <<Supplementary Notes>> The following supplementary notes are further disclosed in relation to the above-described embodiments of the present invention.

[0084] [Supplementary Note 1] A concrete tank comprising: a first space that stores an electrolyte solution to be supplied to a battery cell; and an outer wall that forms at least a part of a dike that surrounds the periphery of the battery cell.

[0085] The concrete tank of Supplementary Note 1 can prevent the leaked electrolyte from leaking outside the embankment, even if the electrolyte sent from the concrete tank to the battery cell leaks from the battery cell.

[0086] REFERENCE SIGNS LIST 1 Redox flow battery system, 10 Battery cell, 100 Cell stack, 2 Main container, 21 Bottom, 211 Recess, 22 Ceiling, 23 First side wall, 24 Second side wall, 3 Concrete tank, 31, 31a, 31b First concrete tank, 32, 32a, 32b Second concrete tank, 33, 33a, 33b First space, 331 First inner surface, 34 Second space, 341 Second inner surface, 35 Ceiling, 35a Wall, 351 First wall, 352 Second wall, 353 Third wall, 354 Fourth wall, 35b Convex, 36 Side wall, 361 Outer wall, 361a First outer wall, 361b Second outer wall 362 Inner wall portion, 37 Partition portion, 38a Common wall portion, 38b Expansion wall portion, 39 Rib, 4 Liquid-proof structure, 41 Base portion, 42 Embankment portion, 43 First connecting wall portion, 44 Second connecting wall portion, 5 Sub-container, 55 Ceiling portion, 6 Pump, 7 Fixing structure, 9 Electrolyte.

Claims

1. A redox flow battery system comprising: a main container in which battery cells are housed; and a concrete tank having a first space in which an electrolyte to be supplied to the battery cells is stored.

2. The redox flow battery system according to claim 1, further comprising a liquid-proof structure having a dike portion surrounding the periphery of the main container, at least a portion of the dike portion being constituted by the outer wall of the concrete tank.

3. The redox flow battery system according to claim 2, further comprising a first container disposed on an upper surface of a ceiling portion of the concrete tank, the first container being the main container.

4. The redox flow battery system as described in claim 2, comprising: a sub-container for storing electrolyte to be supplied to the battery cells; and a first container arranged on an upper surface of a ceiling portion of the concrete tank, wherein the first container is the sub-container, and the main container is arranged on the upper surface of the ceiling portion of the first container.

5. A redox flow battery system as described in claim 3 or claim 4, wherein the concrete tank has a wall portion that protrudes upward from the upper surface of the ceiling portion of the concrete tank so as to surround the periphery of the first container, the liquid-proof structure further has a base portion on which the first container is placed, the embankment portion is the wall portion, and the base portion is the ceiling portion of the concrete tank.

6. The redox flow battery system according to claim 3 or 4, wherein the concrete tank has a fixing structure for fixing the first container to the upper surface of the ceiling portion of the concrete tank.

7. The redox flow battery system according to claim 3 or 4, further comprising a pump for flowing the electrolyte through the battery cells, and the concrete tank further has a second space in which the pump is housed.

8. The redox flow battery system according to claim 7, wherein the first container is disposed at a location on the upper surface of the ceiling portion of the concrete tank corresponding to above the second space.

9. The redox flow battery system according to claim 3 or 4, wherein the first container is arranged so as to overlap a side wall portion of the concrete tank.

10. The redox flow battery system according to any one of claims 1 to 9, wherein the concrete tank has a rib protruding toward the first space.

11. A redox flow battery system as described in any one of claims 1 to 10, wherein the concrete tank has a first concrete tank and a second concrete tank adjacent to each other in the horizontal direction, and a side wall portion of the first concrete tank and a side wall portion of the second concrete tank have a shared wall portion that is shared with each other.

12. A redox flow battery system according to any one of claims 1 to 10, wherein the side wall portion of the concrete tank has an additional wall portion that is shared with the side wall portion of the additional concrete tank.

13. The redox flow battery system of claim 2, wherein the main container and the concrete tank are spaced apart horizontally.

14. The redox flow battery system according to claim 13, wherein the embankment portion comprises a side wall portion of the concrete tank.

15. The redox flow battery system of claim 14, wherein the concrete tank has a first concrete tank and a second concrete tank arranged horizontally at a distance from each other on either side of the main container, the liquid-proof structure further has a base portion on which the main container is arranged, the embankment portion has a first outer wall portion of the first concrete tank, a second outer wall portion of the second concrete tank, and a first connecting wall portion and a second connecting wall portion connecting the first outer wall portion and the second outer wall portion on either side of the main container, and the base portion is surrounded by the first outer wall portion, the second outer wall portion, the first connecting wall portion, and the second connecting wall portion.

16. The redox flow battery system according to claim 15, further comprising a sub-container for storing an electrolyte to be supplied to the battery cell, the sub-container being disposed inside the dike portion.

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