JP2012099368A - Cell stack, cell frame, redox flow battery, and cell stack manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cell stack, from which it is more difficult to leak an electrolyte than a conventional constitution.SOLUTION: In a cell stack 1, a laminate formed by laminating plural cell frames 120 having bipolar plates 121 integrated with frame bodies 122, electrodes 104, 105 and ion-exchange membranes 101 is sandwiched between two end plates 210 and 220 from both sides, and is fastened by a fastening mechanism 230 having a fastening shaft 231 and nuts 232, 233. The cell stack 1 is provided with a holding member 10 for holding a gap between both of the end plates 210 and 220 by being sandwiched between the two end plates 210 and 220 on an outer side than a seal member 127 for sealing an electrolyte on a central side of the frame body 122. The holding member 10 has higher creep resistance than that of the cell frame 120, and a length almost identical to total thickness of the cell frames 120 to be laminated.

Description

  The present invention relates to a cell stack that is a component part of a redox flow battery used as a large-capacity storage battery, a redox flow battery that uses the cell stack, a cell frame that is a component part of the cell stack, and this cell frame. The present invention relates to a method of manufacturing a used cell stack.

  One of the large-capacity storage batteries that store new energy such as solar power generation and wind power generation is a redox flow battery (RF battery). An RF battery is a battery that charges and discharges using a difference in oxidation-reduction potential between ions contained in a positive electrode electrolyte and ions contained in a negative electrode electrolyte. As shown in the operational principle diagram of the RF battery in FIG. 6, the RF battery includes a cell 100 separated into a positive electrode cell 102 and a negative electrode cell 103 by an ion exchange membrane 101 that transmits hydrogen ions. A positive electrode 104 is built in the positive electrode cell 102, and a positive electrode tank 106 for storing a positive electrode electrolyte is connected via conduits 108 and 110. Similarly, a negative electrode 105 is built in the negative electrode cell 103, and a negative electrode tank 107 for storing a negative electrode electrolyte is connected through conduits 109 and 111. The electrolyte stored in the tanks 106 and 107 is circulated to the cells 102 and 103 by the pumps 112 and 113.

  A configuration called a cell stack in which a plurality of cells 100 are stacked is generally used for the RF battery (see, for example, Patent Document 1). FIG. 7 is a schematic configuration diagram of a cell stack. The cell stack 200 is formed by laminating a cell frame 120 including a bipolar plate 121 integrated with a frame body 122, a positive electrode 104, an ion exchange membrane 101, and a negative electrode 105 in this order. In the case of this configuration, one cell is formed between the bipolar plates 121 of the adjacent cell frames 120. The flow of the electrolytic solution in the cell stack 200 is performed by the liquid supply manifolds 123 and 124 formed in the frame body 122 and the drainage manifolds 125 and 126. For example, the positive electrode electrolyte is supplied from the liquid supply manifold 123 to the positive electrode 104 through a groove formed on one surface side (the front side of the paper surface) of the frame body 122, and the groove formed on the upper portion of the frame body 122. Then, the liquid is discharged to the drainage manifold 125. Similarly, the negative electrode electrolyte is supplied from the liquid supply manifold 124 to the negative electrode 105 through a groove formed on the other surface side (the back side of the paper) of the frame 122, and is formed on the upper portion of the frame 122. The liquid is discharged to the drainage manifold 126 through the groove.

  Since the cell stack 200 is a laminated body in which the cell frame 120, the electrodes 104 and 105, and the ion exchange membrane 101 are laminated, it is necessary to prevent the electrolyte from leaking from the gaps between the members. Usually, with an annular seal member 127 such as an O-ring or flat packing disposed between the cell frames 120, the laminate is sandwiched between the two end plates 210 and 220 from both sides and tightened to leak electrolyte. Is preventing.

  FIG. 8 is a partial cross-sectional view of the cell stack showing a tightened state of the stacked body in the cell stack. The tightening mechanism 230 for tightening the laminated body includes a tightening shaft 231, nuts 232 and 233 that are screwed to both ends of the tightening shaft 231, and a compression spring 234 that is interposed between the nut 232 and the end plate 210. Prepare. The tightening mechanism 230 tightens the stacked body with an inward pressure that compresses the stacked body in the stacking direction, thereby preventing a gap between the cell frames 120. The outward pressure acting in the direction of spreading the laminated body is balanced against the inward pressure, and electrolyte leakage over a long period is suppressed. The outward pressure includes the repulsive force of the electrodes 104 and 105, the cell frame 120, and the seal member 127 against the tightening, the pressure of the electrolyte, and the like.

JP 2002-367660 A

  However, even with the configuration of Patent Document 1, the electrolyte solution may easily leak over time.

  In the RF battery, when neither charging nor discharging is performed, the cell stack 200 is stopped in order to stop the flow of the electrolyte to the cell stack 200 in order to reduce the loss of standby power, or to suppress the self-discharge in the cell stack 200. Remove the electrolyte from the operation. In such a case, the inward pressure by the tightening mechanism 230 is greater than the outward pressure, and an excessive compressive force acts on the cell frame 120. The cell frame 120 is usually made of polyvinyl chloride (PVC), polyethylene (PE), polypropylene (PP) or the like in order to ensure corrosion resistance and insulation, and creeps when a strong compressive force is applied for a long time. Become thinner. As a result, there is a possibility that the electrolyte solution in the cell stack 200 is insufficiently sealed.

  The present invention has been made in view of the above circumstances, and one of its purposes is to provide a cell stack in which electrolyte solution is less likely to leak than the conventional configuration, and a redox flow battery using the cell stack. . Another object of the present invention is to provide a cell frame for use in a cell stack in which an electrolyte solution is less likely to leak than in the prior art, and a cell stack manufacturing method for manufacturing a cell stack using the cell frame.

  According to the present invention, a laminated body in which a cell frame, a positive electrode, a negative electrode, and an ion exchange membrane are laminated is sandwiched between two end plates from both sides, and a fastening mechanism including a fastening shaft and a nut is provided. The present invention relates to a cell stack configured by tightening. The cell frame includes a frame body, a bipolar plate integrated with the frame body, and an annular seal member that is provided on the frame body and traps the electrolytic solution on the center side of the frame body. The cell stack according to the present invention includes a holding member that holds a gap between the two end plates by being sandwiched between the two end plates at a position outside the seal member in the frame. The holding member is characterized by being superior in creep resistance than the cell frame and having a length substantially equal to the total thickness of the cell frames to be laminated.

  According to the configuration of the cell stack of the present invention, for example, by stopping the supply of the electrolyte solution to the cell stack, even when the outward pressure is reduced, an excessive compressive force is applied to each cell frame sandwiched between the end plates. It can suppress acting. This is because the distance between the end plates is held by a holding member sandwiched between the two end plates so that the distance between the end plates does not become a certain value or less.

  Hereinafter, a preferred embodiment of the cell stack of the present invention, a configuration of a cell frame used for the cell stack, and the like will be described.

  As one form of the cell stack of the present invention, the holding member is preferably formed in a cylindrical shape, and the fastening shaft of the fastening mechanism passes through the inside of the cylinder.

  If it is the said structure, positioning of the holding member in a cell stack can be performed easily. Further, with this configuration, it is possible to prevent the holding member from coming off between the end plates.

  As one form of this invention cell stack, it is preferable that a holding member consists of a some division | segmentation piece (pressure support member), and the pressure support member is individually provided in each cell frame. Specifically, the frame body of the cell frame is provided with a seal groove into which a sealing member for containing the electrolytic solution is fitted at the center side of the frame body, and the thickness of the frame body is set outside the seal groove. A pressure support member having a substantially equal length is provided. In that case, the holding member is formed by connecting the pressure support members of the plurality of stacked cell frames in series. Here, the pressure support member may have a cylindrical shape capable of penetrating the tightening shaft, or may be a solid column shape. It is preferable that each pressure support member has the same end surface shape, whether cylindrical or columnar. By doing so, the pressure per unit area acting on the end face of each pressure support member can be made uniform.

  Here, when the holding member is made of a single member instead of a plurality of divided pieces, the surface pressure acting on the entire laminate from the end plate can be reduced, but it acts individually on each cell frame in the laminate. The surface pressure to be controlled cannot be controlled. Normally, each cell frame constituting the laminate cannot have the same creep resistance, and even a single cell frame has a slight difference in creep resistance depending on the location. Deformation may occur in inferior parts. On the other hand, if a pressure support member is individually provided for each cell frame, the pressure support member can receive a surface pressure acting on each cell frame, and as a result, the cell frame can be further deformed. It can be effectively suppressed.

  Also, in the case of a holding member made of one member, the end plate is not attached to the cell frame constituting the laminate until the end plate comes into contact with both ends of the holding member after the laminate starts to be compressed between the two end plates. The surface pressure applied from directly acts. On the other hand, when each cell frame has a pressure support member individually, it is possible to reduce the surface pressure acting on each cell frame from the start to the end of compression of the laminate.

  The pressure support member, which is a divided piece of the holding member, may be configured to be detachable from the frame. In that case, it is preferable that a flange extending in a direction orthogonal to the axial direction of the pressure support member is formed on one end side in the axial direction of the pressure support member.

  By making the pressure support member detachable from the frame, only the pressure support member can be exchanged. With such a configuration, when replacing the parts of the cell stack over time, it is possible to save members when it is sufficient to replace only the pressure support member instead of the entire cell frame. In addition, when the cell frame is disposed of, it becomes easy to sort by material. Further, by forming the flange on the pressure support member that is detachable from the frame body, it is possible to easily align the frame body and the pressure support member in the thickness direction of the frame body.

  Furthermore, as one embodiment of the cell stack of the present invention, when the pressure support member is a metal member provided in the cell frame, the frame body includes a drainage groove formed so as to surround the periphery of the pressure support member. Is preferred. This drainage groove is electrolyzed so that when the electrolyte leaks outside from the seal member (seal groove) provided in the frame of the cell frame, the leaked electrolyte is difficult to contact the pressure support member. It is a groove that allows liquid to escape.

  According to the above configuration, even if the electrolyte solution leaks outside from the seal member (seal groove), the possibility that the leaked electrolyte solution contacts the metal pressure support member can be reduced. It can suppress that the electric power to be lost is lost via a pressure support member.

Of the cell frame configurations provided in the cell stack described above, the use of a cell frame including a cylindrical pressure support member can facilitate the manufacture of the cell stack. A method for manufacturing a cell stack using a cell frame including a cylindrical pressure support member includes the following steps.
[Step A] A fastening shaft is attached to one end plate.
[Step B] A laminate including a cell frame having a cylindrical pressure support member is disposed on the end plate. Here, the fastening shaft is inserted into the cylindrical inside of the pressure support member provided in the cell frame.
[Step C] Place the other end plate on the laminate and tighten the fastening shaft with a nut.

  The arrangement of the stacked body in the step B of the cell stack manufacturing method may be performed by stacking cell frames, electrodes, and ion exchange membranes one by one on the end plate, and a predetermined number of cell frames and You may carry out by repeating an electrode and an ion exchange membrane, and mounting on an end plate.

  The cell stack described above can be used as a constituent member of a redox flow battery (RF battery). That is, the RF battery of the present invention includes the cell stack of the present invention, a positive electrode circulation mechanism that circulates the positive electrode electrolyte in the cell stack, and a negative electrode circulation mechanism that circulates the negative electrode electrolyte in the cell stack. Features.

  The RF battery circulation mechanism of the present invention is similar to the conventional RF battery in that the tank for storing the electrolyte, the conduit for sending the electrolyte from the tank to the cell stack, and the electrolyte for returning the electrolyte from the cell stack to the tank A drain pipe and a liquid delivery device such as a pump for circulating the electrolytic solution are included.

  Since the cell stack of the present invention has a structure in which the electrolyte does not easily leak over a long period of time, the RF battery using this cell stack is safe and requires little maintenance. As a result, the safety of the power storage system using the RF battery can be increased, and the maintenance work of the power storage system can be reduced.

  According to the cell stack and the cell frame of the present invention, it is possible to produce an RF battery in which the electrolyte is less likely to leak than in the past.

3 is a partial cross-sectional view of the cell stack shown in Embodiment 1. FIG. 6 is a partial cross-sectional view of a cell stack shown in Embodiment 2. FIG. (A) is a front view of a cell frame used for the cell stack of Embodiment 1, (B) is a cross-sectional view taken along the line II of (A), and (C) is a cross-sectional view taken along the line II of (A) in the modification. FIG. 6 is a partial cross-sectional view of a cell stack shown in Embodiment 3. FIG. The front view of the cell frame shown in Embodiment 4, (B) is II sectional drawing of (A). It is an operation | movement principle figure of a redox flow battery. It is a schematic block diagram of the conventional cell stack. It is a fragmentary sectional view of the conventional cell stack.

  Hereinafter, embodiments of the redox flow battery (RF battery) of the present invention will be described with reference to the drawings. The RF battery of the present invention is characterized by a part of the cell stack provided in the RF battery, and the other configuration has the same configuration as the conventional RF battery described with reference to FIGS. Therefore, in the following embodiment, the difference from the conventional RF battery, that is, the difference from the conventional cell stack will be mainly described, and the same reference numerals as those in FIGS. The description is omitted.

<Embodiment 1>
As shown in FIG. 1, in the cell stack 1 of this embodiment, a cell frame 120, a positive electrode 104, a negative electrode 105, and an ion exchange membrane 101 are appropriately laminated as in the conventional cell stack 200 with reference to FIG. The laminated body is sandwiched between end plates 210 and 220 and is tightened with a tightening mechanism 230. The cell stack 1 of this embodiment further includes a holding member 10 that is sandwiched between the end plates 210 and 220.

  The holding member 10 is a member that holds the distance between the plates 210 and 220 so that an excessive compressive force does not act on the cell frame 20 fastened by the end plates 210 and 220. From this point of view, the holding member 10 is made of a material having higher hardness and higher Young's modulus creep resistance than the cell frame 120 made of PVC or PE. Examples of such materials include metals, particularly alloys such as SUS, ceramics, fiber reinforced plastics, and the like. In particular, SUS is preferable because it is excellent not only in creep resistance but also in corrosion resistance.

  The length of the holding member 10 is substantially the same as the total thickness of the cell plates 120 sandwiched between the end plates 210 and 220. Therefore, if the holding member 10 is arranged between the end plates 210 and 220, when the laminate is tightened and compressed, the laminate can be compressed so that there is almost no gap between the cell frames 120, It is possible to avoid the laminate from being compressed beyond the total thickness of the cell frame 120. As a result, it is possible to suppress an excessive compressive force from acting on the cell frame 120 and to suppress creep deformation of the cell frame 120. The cross-sectional shape of the holding member 10 is not particularly limited, and may be, for example, an ellipse including a perfect circle or a polygon.

  Moreover, the holding member 10 in this embodiment is a cylindrical member through which the fastening shaft 231 of the fastening mechanism 230 passes. The number of holding members 10 may be the same as the number of fastening shafts 231 or may be smaller than the number of fastening shafts 231. In the latter case, it is preferable that the holding members 10 are arranged at equal intervals around the laminated body.

<Embodiment 2>
In the second embodiment, a cell stack that can more effectively suppress the creep deformation of the cell frame than the cell stack of the first embodiment will be described with reference to FIGS. The cell stack of the second embodiment is different from the first embodiment in the position where the holding member is provided, and the configuration of the cell frame is different with the difference.

  As shown in FIG. 2, in the cell stack 2 of the present embodiment, a cylindrical holding member 10 is provided in the cell frame 20, and the fastening shaft 231 of the fastening mechanism 230 passes through the holding member 10. Yes. The holding member 10 is formed by connecting a plurality of divided pieces (pressure support members 11) individually provided on the cell frame 20 in series. Each pressure support member 11 is formed integrally with the cell frame 20.

  As shown in FIG. 3A, the cell frame 20 used in the present embodiment includes a frame body 22 and a bipolar plate 21 integrated with the frame body 22. Of the cell frame 20, the bipolar plate 21 has the same configuration as the conventional one, and the frame 22 has a different configuration from the conventional one. Hereinafter, the configuration of the frame 22 will be described in detail.

  The frame body 22 is formed with manifolds 123 to 126 that serve as a flow path for the electrolyte solution as in the conventional frame body. On the front side of the frame 22 (the side on which the positive electrode is disposed, the side shown in FIG. 3A), the positive electrode liquid supply manifold 123 (drainage manifold 125) is directed to the bipolar plate 21. A liquid groove 123G (liquid groove 125G) is formed. On the other hand, on the back side of the frame 22, although not shown, a liquid groove is formed from the negative manifolds 124 and 126 toward the bipolar plate.

  An annular groove for fitting a negative electrode electrolyte solution from the manifolds 124, 126 to the front side of the frame body 22 around the negative electrode manifolds 124, 126 on the front side of the frame body 22. 124G and 126G are formed. Here, on the back side of the frame body 22, an annular groove is formed around the manifolds 123 and 125, so that the positive electrode electrolyte does not leak to the back side of the frame body 22.

  A sealing mechanism is provided around the electrolyte flow path including the manifolds 123 to 126 and the liquid grooves 123G and 125G to prevent leakage of the electrolyte solution outside the cell frame 20 by surrounding these components. Yes. In the present embodiment, a seal mechanism is formed by an annular seal groove 127G formed in the frame body 22 and a seal member 127 (see FIG. 2) such as an O-ring or a flat packing fitted in the seal groove 127G. In addition, the electrolytic solution is sealed inside the seal groove 127G (seal member). In addition, the sealing mechanism may be formed by heat-sealing the stacked cell frames 20 (frame body 22). In that case, it is preferable to dispose a conductive member for energization in the frame body 22, energize the conductive member, melt the frame body 22 by Joule heat, and fuse the frame bodies 22 to each other.

  Further, a protrusion 22P that protrudes outward from the frame 22 is formed on the outermost periphery of the frame 22, and the cylindrical pressure support member 11 is integrally formed with the protrusion 22P. The pressure support member 11 is one of the cylindrical divided pieces constituting the holding member 10 as described above (see FIG. 2).

  The pressure support member 11 is a metal cylindrical body integrated with the protruding portion 22P of the frame body 22 by insert molding, and has flanges 11F at both ends thereof as shown in FIG. The axial length of the pressure support member 11 including the flange 11 </ b> F is equal to the thickness of the protruding portion 22 </ b> P of the frame body 22, that is, the thickness of the frame body 22. Therefore, the flange 11 </ b> F of the pressure support member 11 is flush with the protrusion 22 </ b> P of the frame body 22. Further, by making the length of the pressure support member 11 equal to the thickness of the protruding portion 22P, the length when the pressure support members 11 of the stacked cell frames 20 are connected in series, that is, the length of the holding member 10 is , Equal to the total thickness of the stacked cell frames 20.

  By providing the pressure support member 11 individually on each cell frame 20, not only can the surface pressure acting on the entire laminate be reduced, but also the surface pressure acting individually on each cell frame 20 can be reduced. As a result, the creep deformation of the cell frame 20 due to the use of the cell stack 2 can be more effectively suppressed than the configuration of the first embodiment.

  A drainage groove 22G provided so as to surround the pressure support member 11 is formed in the protrusion 22P where the pressure support member 11 is provided (see FIG. 3A). By this drainage groove 22G, in the unlikely event that the electrolyte leaks to the outside of the seal groove 127G, the electrolyte can be released so that it does not contact the pressure support member 11, and power can be supplied from the electrolyte to the holding member 10. It can prevent you from escaping.

  In addition, unlike FIG. 3, you may embed the pressure support member 11 by insert molding in the outer peripheral part of the frame 22 which has a rectangular outline shape, without forming the protrusion part 22P.

  Here, the configuration of the present embodiment also has an effect that the manufacturing operation of the cell stack 2 is facilitated. Therefore, a method for manufacturing the cell stack 2 will be described below.

  In order to manufacture the cell stack 2 shown in FIG. 2, first, the fastening shaft 231 and the nut 233 are attached to the end plate 220.

  Next, the end plate 220 to which the fastening shaft 231 is attached is parallel to the ground, and the laminate is stacked on the end plate 220. At this time, since the cylindrical pressure support member 11 is provided in the cell frame 20 included in the laminate, the fastening shaft 231 is inserted into the cylinder. By doing so, the laminated body can be easily positioned with respect to the end plate 220. The laminate may be performed by stacking the cell frame 20, the electrodes 104, 105, and the ion exchange membrane 101 one by one on the end plate 220, or a predetermined number of cell frames 20, electrodes 104, 105, You may perform by repeating mounting the laminated body which laminated | stacked the ion exchange membrane 101 on the end plate 220. FIG.

  Next, the end plate 210 is disposed on the laminate disposed on the end plate 220, and the nut 232 is attached to the end of the tightening shaft 231. At this time, a compression spring 234 is disposed between the nut 232 and the end plate 210. Then, the nut 232 is tightened until the two end plates 210 and 220 are abutted against the holding member 10 that is an assembly of the pressure support members 11, and the laminated body between the end plates 210 and 220 is compressed.

  As described above, in the cell stack 2 according to the second embodiment, the stacked body can be positioned with respect to the end plate 210 at the same time that the stacked body is disposed on the end plate 210. Moreover, when the cell stack 2 is assembled, there is also an advantage that the position of each component of the stacked body is difficult to shift.

<Modified Embodiment>
As a modified embodiment of the first embodiment, a configuration in which the pressure support member is detachable from the frame will be described with reference to FIG.

  As shown in FIG. 3C, the pressure support member 12 of the present embodiment includes an annular flange 12F extending in a direction orthogonal to the axial direction of the pressure support member 12 only at one end side in the axial direction. Further, the protrusion 22P of the frame 22 has a large-diameter portion having an inner peripheral shape that matches the outer peripheral shape of the flange 12F of the pressure support member 12, and an inner peripheral shape that matches the outer peripheral shape of the portion other than the flange 12F. The fitting hole which consists of a small diameter part with which it is provided is formed. According to this configuration, the pressure support member 12 can be easily fitted into the fitting hole, and the end surface of the pressure support member 12 fitted into the frame body 22 and the surface of the frame body 22 can be flush with each other. it can. As long as the flange 12F of the pressure support member 12 faces vertically upward, the pressure support member 12 does not easily fall out of the frame body 22, and therefore, when assembling the cell stack, the flange 12F faces upward. It is good to leave.

<Embodiment 3>
In the third embodiment, a cell stack 3 in which a columnar pressure support member 13 is provided on a cell frame 20 will be described with reference to FIG.

  In the cell stack 3, a columnar pressure support member 13 is embedded in the protruding portion 22P of the cell frame 20 described with reference to FIG. By using the solid pressure support member 13 such as a columnar shape, the surface pressure for compressing the laminate can be more reliably received over a long period of time than the cylindrical pressure support member.

  In addition, in the cell stack 3 of this embodiment, the clamping shaft 231 cannot be penetrated into the pressure support member 13 by making the pressure support member 13 into a columnar shape. Therefore, in the cell stack 3, the fastening shaft 231 is disposed on the outer peripheral side of the cell frame 20.

<Embodiment 4>
In the fourth embodiment, a cell stack in which the pressure support member 12 according to the modified embodiment described with reference to FIG. 3C is provided on an existing cell frame 20 ′ will be described with reference to FIG.

  In this cell stack, a fitting hole is formed in the outer peripheral edge of the existing cell frame 20 ', and the pressure support member 12 is fitted into the fitting hole. As described above, the pressure support member 12 includes the annular flange 12F only at one end side in the axial direction, and the fitting hole into which the pressure support member 12 is fitted has an outer peripheral shape of the flange 12F of the pressure support member 12. And a small-diameter portion that matches the outer peripheral shape of the portion other than the flange 12F.

  According to the configuration described above, even with the existing cell frame 20 ′, the creep deformation of the cell frame 20 ′ can be effectively suppressed only by adding the pressure support member 12.

  In the case of this embodiment as well, a drainage groove is formed so as to surround the pressure support member 12, and when the electrolyte leaks outside the seal groove 127 </ b> G, the electrolyte does not contact the pressure support member 11. You may make it escape.

  The embodiment of the present invention is not limited to the above-described embodiment, and can be changed as appropriate without departing from the gist of the present invention. For example, in Embodiment 3, you may add the holding member 10 of Embodiment 1 demonstrated with reference to FIG.

  The cell stack and the cell frame of the present invention can be suitably used for a redox flow battery used for a power storage system.

1, 2, 3 Cell stack 10 Holding member 11, 12, 13 Pressure support member 11F, 12F Flange 20, 20 'Cell frame 21 Bipolar plate 22 Frame body 22P Protruding portion 22G Drainage groove 123, 124 Manifold for liquid supply 125, 126 Manifold for drainage 123G, 125G Liquid groove 124G, 126G Annular groove 127 Seal member 127G Seal groove 230 Tightening mechanism 231 Tightening shaft 232, 233 Nut 234 Compression spring 210, 220 End plate 100 Cell 101 Ion exchange membrane 102 Positive electrode cell DESCRIPTION OF SYMBOLS 104 Positive electrode 106 Positive electrode electrolyte tank 108,110 Conduit 112 Pump 103 Negative electrode 105 Negative electrode 107 Negative electrode electrolyte tank 109,111 Conduit 113 Pump 120 Cell frame 121 Bipolar plate 122 Frame 200 Subordinate Coming cell stack

Claims (10)

Constructed by sandwiching a stack of multiple cell frames, positive electrodes, negative electrodes, and ion exchange membranes between two end plates from both sides and tightening with a tightening mechanism with a tightening shaft and nut Cell stack,
The cell frame includes a frame, a bipolar plate integrated with the frame, and an annular seal member that is provided in the frame and traps the electrolyte solution at the center side of the frame,
A holding member that holds an interval between both end plates by being sandwiched between two end plates at a position outside the seal member in the frame body,
The cell stack is characterized in that the holding member has a creep resistance superior to that of the cell frame and has a length substantially equal to the total thickness of the laminated cell frames.   The cell stack according to claim 1, wherein the holding member is formed in a cylindrical shape, and a clamping shaft of a clamping mechanism passes through the cylinder. The holding member is formed by connecting in series a pressure support member provided individually in the frame of each cell frame,
The pressure support member has a length substantially equal to the thickness of the frame body, and is a pressure generated by the tightening of the tightening mechanism, and supports the pressure for compressing the stacked cell frames in the thickness direction. The cell stack according to claim 1, wherein the cell stack is provided. The pressure support member is configured to be detachable from the frame, and
The cell stack according to claim 3, wherein a flange extending in a direction orthogonal to the axial direction of the pressure support member is formed at one end of the pressure support member. The pressure support member is a metal member provided in the cell frame,
The frame includes a drainage groove formed to surround the periphery of the pressure support member,
When the electrolyte leaks outside from the sealing member, the electrolyte is allowed to escape to the drainage groove so that the leaked electrolyte becomes difficult to contact the pressure support member. Item 5. The cell stack according to Item 3 or 4. A frame, a bipolar plate integrated with the frame, and a seal groove into which a seal member for confining the electrolyte solution is fitted in the center of the frame;
A cell frame that constitutes a cell stack by being laminated together with a positive electrode, a negative electrode, and an ion exchange membrane,
A pressure support member that is disposed outside the seal groove in the frame and supports the pressure for compressing the cell frame in the thickness direction;
The cell frame, wherein the pressure support member has a length substantially equal to the thickness of the frame.   The said pressure support member has a flange extended in the direction orthogonal to the axial direction of a pressure support member in the one end side of the axial direction, and is comprised so that attachment or detachment with respect to a frame is possible. The cell frame described in.   The cell frame according to claim 6 or 7, wherein the pressure support member is formed in a cylindrical shape. The cell stack according to any one of claims 1 to 5,
A positive electrode circulation mechanism for circulating the positive electrode electrolyte in the cell stack;
A negative electrode circulation mechanism for circulating the negative electrode electrolyte in the cell stack;
A redox flow battery comprising: Constructed by sandwiching a stack of multiple cell frames, positive electrodes, negative electrodes, and ion exchange membranes between two end plates from both sides and tightening with a tightening mechanism with a tightening shaft and nut A cell stack manufacturing method for manufacturing a cell stack comprising:
Step A in which a fastening shaft is attached to one end plate;
Step B for disposing a laminate including the cell frame according to claim 8 on the end plate;
A step C of disposing the other end plate on the laminate and tightening the tightening shaft with a nut; and
A method of manufacturing a cell stack, wherein a clamping shaft is inserted into a cylinder of a pressure support member provided in the cell frame in step B.

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