WO2018134927A1 - Bipolar plate, cell frame, cell stack, and redox flow cell - Google Patents

Bipolar plate, cell frame, cell stack, and redox flow cell Download PDF

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Publication number
WO2018134927A1
WO2018134927A1 PCT/JP2017/001614 JP2017001614W WO2018134927A1 WO 2018134927 A1 WO2018134927 A1 WO 2018134927A1 JP 2017001614 W JP2017001614 W JP 2017001614W WO 2018134927 A1 WO2018134927 A1 WO 2018134927A1
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Prior art keywords
bipolar plate
cell
frame
redox flow
electrolyte
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PCT/JP2017/001614
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French (fr)
Japanese (ja)
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山口　英之
本井　見二
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住友電気工業株式会社
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Priority to PCT/JP2017/001614 priority Critical patent/WO2018134927A1/en
Publication of WO2018134927A1 publication Critical patent/WO2018134927A1/en

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/02—Details
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/02—Details
    • H01M8/0202—Collectors; Separators, e.g. bipolar separators; Interconnectors
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/18—Regenerative fuel cells, e.g. redox flow batteries or secondary fuel cells
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/30—Hydrogen technology
    • Y02E60/50—Fuel cells

Definitions

  • the present invention relates to a bipolar plate, a cell frame, a cell stack, and a redox flow battery.
  • Patent Documents 1 and 2 describe a cell stack formed by laminating a plurality of cell frames, positive electrodes, diaphragms, and negative electrodes, and a redox flow battery using the cell stack.
  • the cell frame includes a bipolar plate disposed between the positive electrode and the negative electrode, and a frame provided on the outer periphery of the bipolar plate.
  • positive and negative electrodes are arranged between bipolar plates of adjacent cell frames with a diaphragm interposed therebetween, thereby forming one cell.
  • a redox flow battery performs charge and discharge by circulating and circulating an electrolytic solution in a cell in which electrodes are arranged.
  • the bipolar plate of the present disclosure is A bipolar plate on which electrodes of a redox flow battery are arranged,
  • the radius of curvature of the corner when the bipolar plate is viewed in plan is 5 mm or more and 100 mm or less.
  • the cell frame of the present disclosure includes the bipolar plate of the present disclosure and a frame body provided on the outer periphery of the bipolar plate.
  • the cell stack of the present disclosure includes the cell frame of the present disclosure.
  • the redox flow battery of the present disclosure includes the cell stack of the present disclosure.
  • FIG. 5 is a schematic partial cross-sectional view of a cell frame taken along line VI-VI in FIG. 4.
  • redox flow batteries have attracted attention as one of storage batteries that stabilize the output of renewable energy such as sunlight and wind power, and further improvements in productivity and reliability of redox flow batteries are required. .
  • a rectangular bipolar plate is used, and when the bipolar plate is viewed in plan in the thickness direction, each corner is substantially perpendicular and the radius of curvature of each corner is small. For this reason, when the bipolar plate is handled, such as during cell frame assembly work, cracks may occur in the corners, which has been one factor in reducing productivity.
  • the present inventors have studied to round the corners in plan view of the bipolar plate and increase the curvature radius of the corners. However, it has been found that if the radius of curvature of the corner is too large, the following problem may occur.
  • the cell frame has a recess formed inside the frame on which the bipolar plate is provided, and the shape of the recess is usually a shape corresponding to the planar shape of the bipolar plate.
  • An electrode having substantially the same size is accommodated in the recess, and a cell is constituted by a space surrounded by the recess and the diaphragm formed by the bipolar plate and the frame.
  • the distance between the edges between the one edge and the other edge of the bipolar plate is the width direction (the direction along one edge and the other edge). )
  • the edge-to-edge distance at the center in the width direction is longer than at both ends where the corners are provided. That is, the flow path length of the electrolytic solution is longer at the central portion in the width direction than at both ends. If the radius of curvature of the corner is too large, the difference in flow path length between the central portion and both end portions in the width direction becomes large, and the flow length of the electrolytic solution becomes longer at the central portion. Easily overcharged.
  • an object of the present disclosure is to provide a bipolar plate, a cell frame, and a cell stack that can improve the productivity and reliability of a redox flow battery.
  • Another object of the present disclosure is to provide a redox flow battery that has excellent productivity and high reliability.
  • the bipolar plate according to the embodiment is A bipolar plate on which electrodes of a redox flow battery are arranged,
  • the radius of curvature of the corner when the bipolar plate is viewed in plan is 5 mm or more and 100 mm or less.
  • the curvature radius (corner R) of the corner when the bipolar plate is viewed in plan in the thickness direction is 5 mm or more, so that the corner is cracked when the bipolar plate is handled. hard. Therefore, it is possible to suppress the occurrence of cracks at the corners of the bipolar plate at the time of assembling the cell frame, and to improve the productivity of the redox flow battery.
  • the angle R in a plan view of the bipolar plate is 100 mm or less, the difference in the flow path length of the electrolyte can be reduced between the central portion in the width direction of the bipolar plate and the end portion provided with the corner portion. Therefore, the electrolyte is unlikely to be overcharged at the center of the bipolar plate, and damage to the electrodes and the like due to overcharge can be suppressed, so that the reliability of the redox flow battery can be improved.
  • bipolar plate One form of the bipolar plate is that the planar shape of the bipolar plate is rectangular.
  • planar shape of the bipolar plate (the shape when the bipolar plate is viewed in plan in the thickness direction) is a rectangular shape, both edges facing each other have parallel straight sides and the width excluding the corners
  • the flow path length of the electrolyte solution in the central portion in the direction can be made substantially constant over the width direction. Therefore, it is easy to suppress overcharging at the center in the width direction of the bipolar plate.
  • a cell frame according to the embodiment includes the bipolar plate according to the above (1) or (2) and a frame body provided on an outer periphery of the bipolar plate.
  • the productivity and reliability of the redox flow battery can be improved.
  • a cell stack according to the embodiment includes the cell frame described in (3) above.
  • the cell stack includes the cell frame according to the above-described embodiment, the productivity and reliability of the redox flow battery can be improved.
  • a redox flow battery according to the embodiment includes the cell stack described in (4) above.
  • the RF battery 1 shown in FIG. 1 and FIG. 2 uses an electrolytic solution containing, as an active material, a metal ion whose valence changes as a result of oxidation and reduction in the positive electrode electrolyte and the negative electrode electrolyte.
  • the battery performs charging / discharging by utilizing the difference between the redox potential and the redox potential of ions contained in the negative electrode electrolyte.
  • the RF battery 1 as shown in FIG.
  • a case of a vanadium-based RF battery using a vanadium electrolyte solution containing V ions serving as an active material in a positive electrode electrolyte and a negative electrode electrolyte is shown.
  • a solid line arrow in the cell 100 in FIG. 1 indicates a charging reaction, and a broken line arrow indicates a discharging reaction.
  • the RF battery 1 is one of the electrolyte circulation type storage batteries. For example, applications such as load leveling, sag compensation, emergency power supply, etc., and regeneration of solar and wind power, which are being introduced in large quantities. Used for smoothing output of possible energy.
  • the RF battery 1 includes a cell 100 separated into a positive electrode cell 102 and a negative electrode cell 103 by a diaphragm 101 that transmits hydrogen ions.
  • a positive electrode 104 is built in the positive electrode cell 102, and a positive electrode electrolyte solution tank 106 for storing the positive electrode electrolyte is connected via conduits 108 and 110.
  • the conduit 108 is provided with a pump 112 that pumps the positive electrode electrolyte to the positive electrode cell 102, and a positive electrode circulation mechanism 100 ⁇ / b> P that circulates the positive electrode electrolyte is constituted by these members 106, 108, 110, and 112. .
  • the negative electrode cell 103 contains a negative electrode 105 and is connected to a negative electrode electrolyte tank 107 for storing a negative electrode electrolyte via conduits 109 and 111.
  • the conduit 109 is provided with a pump 113 for pumping the negative electrode electrolyte to the negative electrode cell 103, and a negative electrode circulation mechanism 100N for circulating the negative electrode electrolyte is constituted by these members 107, 109, 111, 113. .
  • the electrolytes stored in the tanks 106 and 107 are circulated in the cell 100 (the positive electrode cell 102 and the negative electrode cell 103) by the pumps 112 and 113 at the time of charging and discharging, and at the time of standby without charging and discharging. Pumps 112 and 113 are stopped and not circulated.
  • the cell 100 is usually formed inside a structure called a cell stack 2 shown in FIGS.
  • the cell stack 2 is configured by sandwiching a laminate called a sub stack 200 (see FIG. 3) from two sides with two end plates 220 and fastening the end plates 220 on both sides with a fastening mechanism 230 (see FIG. 3 includes a plurality of sub-stacks 200).
  • the sub stack 200 is formed by stacking a plurality of cell frames 3, positive electrodes 104, diaphragms 101, and negative electrodes 105, and supply / discharge plates 210 (see the lower figure in FIG. 3, omitted in FIG. 2) at both ends of the laminated body. It is an arranged configuration.
  • the cell frame 3 includes a bipolar plate 31 disposed between the positive electrode 104 and the negative electrode 105, and a frame body 32 provided on the outer periphery of the bipolar plate 31.
  • the positive electrode 104 is disposed on one surface side of the bipolar plate 31 and the negative electrode 105 is disposed on the other surface side of the bipolar plate 31.
  • the sub stack 200 (cell stack 2), one cell 100 is formed between the bipolar plates 31 of the adjacent cell frames 3 respectively.
  • the bipolar plate 31 is made of, for example, plastic carbon, and the frame body 32 is made of, for example, plastic such as vinyl chloride resin (PVC), polypropylene, polyethylene, fluorine resin, or epoxy resin.
  • PVC vinyl chloride resin
  • the bipolar plate 31 can be formed by a known method such as injection molding, press molding, or vacuum molding.
  • the electrolyte solution flows into the cell 100 through supply / discharge plates 210 (see the lower diagram in FIG. 3), and supply manifolds 33, 34 provided through the frame body 32 of the cell frame 3 shown in FIG. This is performed by the drainage manifolds 35 and 36, the liquid supply slits 33s and 34s formed in the frame 32, and the drainage slits 35s and 36s (see also FIG. 4).
  • the positive electrode electrolyte is supplied from the liquid supply manifold 33 provided at the lower part of the frame body 32 on the one surface side (the paper surface side) of the frame body 32.
  • the negative electrode electrolyte is supplied to the negative electrode 105 from a liquid supply manifold 34 provided in the lower part of the frame 32 through a liquid supply slit 34 s formed on the other surface side (back side of the paper) of the frame 32.
  • the liquid is discharged to the drainage manifold 36 through the drainage slit 36s formed in the upper part of the frame 32.
  • a rectifying portion (not shown) may be formed along the edge at the lower edge and the upper edge inside the frame 32 on which the bipolar plate 31 is provided.
  • the rectifying unit diffuses each electrolytic solution supplied from the liquid supply slits 33 s and 34 s along the lower edge portion of each electrode, or discharges each electrolytic solution discharged from the upper edge portion of each electrode to the drain slits 35 s, It has the function of consolidating to 36s.
  • the electrolytic solution is supplied from the lower side of the bipolar plate 31 and is discharged from the upper side of the bipolar plate 31, and electrolysis is performed from the lower edge portion of the bipolar plate 31 toward the upper edge portion. Liquid flows.
  • a thick line arrow on the left side of the drawing indicates an overall electrolyte flow direction of the electrolyte solution in the bipolar plate 31.
  • a plurality of grooves may be formed on the surface of the bipolar plate 31 in contact with each electrode along the flow direction of the electrolytic solution. Thereby, the distribution
  • the cross-sectional shape of the groove (the cross-sectional shape orthogonal to the flow direction of the electrolyte) is not particularly limited, and examples thereof include a rectangular shape, a triangular shape (V shape), a trapezoidal shape, a semicircular shape, and a semielliptical shape. It is done.
  • annular seal member 37 (see FIGS. 2 and 3) such as an O-ring and a flat packing is disposed between the frame bodies 32 of each cell frame 3 in order to suppress leakage of the electrolyte from the cell 100.
  • a seal groove 38 (see FIG. 4) for arranging the seal member 37 is formed in the frame body 32.
  • the radius of curvature (corner R) of the corner when the bipolar plate 31 is viewed in plan is 5 mm or more and 100 mm or less.
  • the bipolar plate 31 has a shape having a corner 40 when viewed in plan.
  • the planar shape of the bipolar plate 31 is a rectangular shape having four corners 41 to 44, and the lower and upper edges of the bipolar plate 31 that are opposite to each other are straight side portions 45 and 46 that are parallel to each other.
  • Have The bipolar plate 31 has round corners 40 in plan view, and the radius of curvature (corner R) of each of the corners 41 to 44 is not less than 5 mm and not more than 100 mm.
  • the size of the bipolar plate 31 for example, the length in the vertical direction (up and down direction in FIG.
  • the length in the width direction (left and right direction in FIG. 5) is 200 mm or more and 2000 mm or less
  • the thickness is It is 3.0 mm or more and 10.0 mm or less.
  • the cell frame 3 is configured by providing a frame 32 on the outer periphery of the bipolar plate 31.
  • the frame 32 has an opening 50 formed therein, and the bipolar plate 31 is disposed in the opening 50.
  • the frame body 32 has a rectangular frame shape, and the opening 50 is formed in a shape corresponding to the outer shape of the bipolar plate 31. That is, the shape of the opening 50 is substantially the same shape (similar shape) as the planar shape of the bipolar plate 31, and the corner of the inner peripheral edge of the frame 32 where the opening 50 is formed is Like the corner 40, it is rounded and has substantially the same corner R as the bipolar plate 31.
  • a stepped portion 51 in contact with the outer peripheral edge of the bipolar plate 31 is formed at the inner peripheral edge of the frame 32, and the outer peripheral edge of the bipolar plate 31 is disposed at the stepped portion 51 as shown in FIG. 6.
  • the bipolar plate 31 is supported by the frame body 32.
  • a groove is formed in the outer peripheral edge portion of the bipolar plate 31 along the circumferential direction on the surface in contact with the stepped portion 51, and a seal member 52 is disposed in the groove.
  • the seal member 52 can suppress the electrolyte solution from moving between the one surface side and the other surface side of the bipolar plate 31.
  • the cell plate 3 When the cell plate 3 is configured by arranging the bipolar plate 31 in the opening 50 of the frame 32, the surface of the bipolar plate 31 and the inner peripheral surface of the frame 32 are placed inside the frame 32 as shown in FIG. 4. A recess 55 is formed. As shown in FIG. 6, the concave portions 55 are formed on both sides of the bipolar plate 31, and the positive electrode 104 and the negative electrode 105 are respectively stored in the concave portions 55. Each of the electrodes 104 and 105 is formed in substantially the same size as each of the recesses 55. In the case of the cell frame 3 shown in FIG. 4, the shape of the recess 55 provided on one surface side is substantially the same as the planar shape of the bipolar plate 31, and the positive electrode 104 accommodated in the recess 55 (see FIG.
  • the electrodes 104 and 105 are arranged on the cell frame 3, and the cell frame 3 is laminated via the diaphragm 101, whereby the cell stack 2 (see FIG. 3) is configured.
  • the bipolar plate 31 according to the embodiment has the following operational effects. Since the corner portion 40 in the plan view of the bipolar plate 31 is formed in a round shape and the corner R is 5 mm or more, it is possible to prevent the corner portion 40 from being cracked. Therefore, when the bipolar plate 31 is handled at the time of assembling the cell frame 3 or the like, the corner portion 40 is hardly cracked. From the viewpoint of suppressing cracking of the corner portion 40, the corner R is, for example, 10 mm or more.
  • both end portions (corner portions 41) in the width direction. , 42 and the region between the corners 43, 44) and the central portion in the width direction (region between the side portions 45, 46) are different in the flow path length of the electrolyte.
  • the flow path length L2 in the width direction center part of the bipolar plate 31 becomes longer than the flow path length L1 in both ends (L2> L1).
  • the flow path length L2 at the center in the width direction of the bipolar plate 31 is constant over the width direction.
  • the angle R is set to 100 mm or less, and the difference between the flow path length L2 at the center in the width direction and the flow path length L1 at both ends is set within a certain range. Has been. This is because the angle R is 100 mm or less, and the difference in the flow path length of the electrolyte solution between the central portion and both end portions in the 31 width direction of the bipolar plate is small. Electrolytic overcharge can be suppressed. Therefore, it is possible to suppress oxidative damage of the electrode and damage to the diaphragm accompanying heat generation due to overcharging of the electrolytic solution. From the viewpoint of suppressing damage to electrodes and the like due to overcharge, the angle R is, for example, 50 mm or less.
  • the ratio (L2 / L1) between the maximum flow path length L2 and the minimum flow path length L1 is, for example, 1.5 or less, 1.3 or less, and further 1.1 or less.
  • a bipolar plate having a rectangular planar shape was prepared.
  • the size (outside dimension) of the bipolar plate is 250 mm long ⁇ 600 mm wide ⁇ 10.0 mm thick.
  • a plurality of bipolar plates (see FIG. 5) having different corner radii of curvature (angles R) in plan view were prepared.
  • a cell frame (see FIG. 4) was prepared using each bipolar plate, and a plurality of RF batteries (test bodies A to G) were assembled using the cell frame. And about each test body, productivity and reliability were evaluated.
  • Evaluation of productivity was made by visually checking whether or not cracks occurred at the corners of the bipolar plate when 100 cell plates were prepared with each bipolar plate. And in 100 pieces, the case where there was no crack in the corner portion was evaluated as “A”, the case where the number of cracks generated in the corner portion was less than 5, “B”, and the case where it was more than “C” was evaluated. . The results are shown in Table 1.

Abstract

In this bipolar plate in which electrodes of a redox flow cell are arranged, the curvature radii of corners when the bipolar plate is viewed in a planar view are in the range of 5-100 mm inclusive.

Description

双極板、セルフレーム、セルスタック、及びレドックスフロー電池Bipolar plate, cell frame, cell stack, and redox flow battery
　本発明は、双極板、セルフレーム、セルスタック、及びレドックスフロー電池に関する。 The present invention relates to a bipolar plate, a cell frame, a cell stack, and a redox flow battery.
　特許文献１～２には、セルフレーム、正極電極、隔膜、負極電極をそれぞれ複数積層してなるセルスタック、及びそのセルスタックを用いたレドックスフロー電池が記載されている。セルフレームは、正極電極と負極電極との間に配置される双極板と、双極板の外周に設けられる枠体とを備える。セルスタックでは、隣接するセルフレームの双極板の間に、隔膜を挟んで正負の電極が配置され、１つのセルが形成される。レドックスフロー電池は、電極が配置されたセル内に電解液を循環流通させて充放電を行う。 Patent Documents 1 and 2 describe a cell stack formed by laminating a plurality of cell frames, positive electrodes, diaphragms, and negative electrodes, and a redox flow battery using the cell stack. The cell frame includes a bipolar plate disposed between the positive electrode and the negative electrode, and a frame provided on the outer periphery of the bipolar plate. In a cell stack, positive and negative electrodes are arranged between bipolar plates of adjacent cell frames with a diaphragm interposed therebetween, thereby forming one cell. A redox flow battery performs charge and discharge by circulating and circulating an electrolytic solution in a cell in which electrodes are arranged.
特開２００２－２４６０６１号公報Japanese Patent Laid-Open No. 2002-246061 特開２００５－２２８６２２号公報JP 2005-228622 A
　本開示の双極板は、
　レドックスフロー電池の電極が配置される双極板であって、
　前記双極板を平面視したときの角部の曲率半径が５ｍｍ以上１００ｍｍ以下である。 The bipolar plate of the present disclosure is
A bipolar plate on which electrodes of a redox flow battery are arranged,
The radius of curvature of the corner when the bipolar plate is viewed in plan is 5 mm or more and 100 mm or less.
　本開示のセルフレームは、本開示の双極板と、前記双極板の外周に設けられる枠体とを備える。 The cell frame of the present disclosure includes the bipolar plate of the present disclosure and a frame body provided on the outer periphery of the bipolar plate.
　本開示のセルスタックは、本開示のセルフレームを備える。 The cell stack of the present disclosure includes the cell frame of the present disclosure.
　本開示のレドックスフロー電池は、本開示のセルスタックを備える。 The redox flow battery of the present disclosure includes the cell stack of the present disclosure.
実施形態に係るレドックスフロー電池の動作原理図である。It is an operation principle figure of the redox flow battery concerning an embodiment. 実施形態に係るレドックスフロー電池の概略構成図である。It is a schematic block diagram of the redox flow battery which concerns on embodiment. 実施形態に係るセルスタックの概略構成図である。It is a schematic block diagram of the cell stack which concerns on embodiment. 実施形態に係るセルフレームを一面側から見た概略平面図である。It is the schematic plan view which looked at the cell frame which concerns on embodiment from the one surface side. 実施形態に係るセルフレームを構成する双極板及び枠体の概略平面図である。It is a schematic plan view of the bipolar plate and frame which comprise the cell frame which concerns on embodiment. 図４のＶＩ－ＶＩ線で切断したセルフレームの概略部分断面図である。FIG. 5 is a schematic partial cross-sectional view of a cell frame taken along line VI-VI in FIG. 4.
　［本開示が解決しようとする課題］
　近年、太陽光や風力などの再生可能エネルギーの出力を安定化させる蓄電池の１つとして、レドックスフロー電池が注目されており、更なるレドックスフロー電池の生産性及び信頼性の向上が求められている。 [Problems to be solved by the present disclosure]
In recent years, redox flow batteries have attracted attention as one of storage batteries that stabilize the output of renewable energy such as sunlight and wind power, and further improvements in productivity and reliability of redox flow batteries are required. .
　一般に、従来のレドックスフロー電池では、矩形状の双極板が使用されており、双極板を厚さ方向に平面視したときの各角部が略直角で、各角部の曲率半径が小さい。そのため、セルフレームの組み立て作業時など、双極板をハンドリングした際に角部に割れが発生することがあり、生産性の低下を招く１つの要因になっていった。 Generally, in a conventional redox flow battery, a rectangular bipolar plate is used, and when the bipolar plate is viewed in plan in the thickness direction, each corner is substantially perpendicular and the radius of curvature of each corner is small. For this reason, when the bipolar plate is handled, such as during cell frame assembly work, cracks may occur in the corners, which has been one factor in reducing productivity.
　そこで、本発明者らは、双極板の角部の割れを抑制するため、双極板の平面視における角部を丸くして、角部の曲率半径を大きくすることを検討した。しかし、角部の曲率半径を大きくし過ぎると、次のような問題が生じ得ることが分かった。 Therefore, in order to suppress cracking at the corners of the bipolar plate, the present inventors have studied to round the corners in plan view of the bipolar plate and increase the curvature radius of the corners. However, it has been found that if the radius of curvature of the corner is too large, the following problem may occur.
　セルフレームは、双極板が設けられる枠体の内側に凹部が形成され、凹部の形状は通常、双極板の平面形状に対応した形状になっている。この凹部に略同じサイズの電極が収納され、双極板及び枠体により形成される凹部と隔膜とで囲まれる空間によってセルが構成される。そして、セル内に電解液を流通させるときは、双極板（電極）の一方の縁部からそれに対向する他方の縁部に向かってセル内を電解液が流れるようになっている。 The cell frame has a recess formed inside the frame on which the bipolar plate is provided, and the shape of the recess is usually a shape corresponding to the planar shape of the bipolar plate. An electrode having substantially the same size is accommodated in the recess, and a cell is constituted by a space surrounded by the recess and the diaphragm formed by the bipolar plate and the frame. When the electrolyte is circulated in the cell, the electrolyte flows in the cell from one edge of the bipolar plate (electrode) toward the other edge facing the bipolar plate (electrode).
　双極板の平面視における角部を丸くした場合、双極板の一方の縁部と他方の縁部との間の縁部間距離が幅方向（一方の縁部及び他方の縁部に沿った方向）で異なり、幅方向の中央部での縁部間距離が、角部が設けられた両端部に比べて長くなる。つまり、幅方向の中央部では、両端部に比べて電解液の流路長が長くなる。角部の曲率半径を大きくし過ぎると、幅方向の中央部と両端部とで流路長の差が大きくなり、中央部で電解液の流路長が長くなることに起因して電解液が過充電状態になり易い。そのため、過充電により熱が発生し、その熱に伴う電解液の温度上昇によって、電極が酸化損傷したり、隔膜が破れたりすることが起こり得る。よって、信頼性の観点から、過充電による電極などの損傷を抑制することが望まれる。 When the corners in plan view of the bipolar plate are rounded, the distance between the edges between the one edge and the other edge of the bipolar plate is the width direction (the direction along one edge and the other edge). ), The edge-to-edge distance at the center in the width direction is longer than at both ends where the corners are provided. That is, the flow path length of the electrolytic solution is longer at the central portion in the width direction than at both ends. If the radius of curvature of the corner is too large, the difference in flow path length between the central portion and both end portions in the width direction becomes large, and the flow length of the electrolytic solution becomes longer at the central portion. Easily overcharged. For this reason, heat is generated by overcharging, and the electrode may be damaged by oxidation or the diaphragm may be broken due to the temperature rise of the electrolyte solution accompanying the heat. Therefore, from the viewpoint of reliability, it is desired to suppress damage to electrodes and the like due to overcharging.
　そこで、本開示は、レドックスフロー電池の生産性及び信頼性の向上を図ることができる双極板、セルフレーム、及びセルスタックを提供することを目的の一つとする。また、本開示は、生産性に優れ、信頼性が高いレドックスフロー電池を提供することを目的の一つとする。 Therefore, an object of the present disclosure is to provide a bipolar plate, a cell frame, and a cell stack that can improve the productivity and reliability of a redox flow battery. Another object of the present disclosure is to provide a redox flow battery that has excellent productivity and high reliability.
　［本開示の効果］
　本開示によれば、レドックスフロー電池の生産性及び信頼性の向上を図ることができる双極板、セルフレーム、及びセルスタックを提供できる。また、本開示によれば、生産性に優れ、信頼性が高いレドックスフロー電池を提供できる。 [Effects of the present disclosure]
According to the present disclosure, it is possible to provide a bipolar plate, a cell frame, and a cell stack that can improve the productivity and reliability of a redox flow battery. In addition, according to the present disclosure, it is possible to provide a redox flow battery having excellent productivity and high reliability.
　［本願発明の実施形態の説明］
　最初に本願発明の実施形態の内容を列記して説明する。 [Description of Embodiment of Present Invention]
First, the contents of the embodiments of the present invention will be listed and described.
　（１）実施形態に係る双極板は、
　レドックスフロー電池の電極が配置される双極板であって、
　前記双極板を平面視したときの角部の曲率半径が５ｍｍ以上１００ｍｍ以下である。 (1) The bipolar plate according to the embodiment is
A bipolar plate on which electrodes of a redox flow battery are arranged,
The radius of curvature of the corner when the bipolar plate is viewed in plan is 5 mm or more and 100 mm or less.
　上記双極板によれば、双極板を厚さ方向に平面視したきの角部の曲率半径（角Ｒ）が５ｍｍ以上であることで、双極板をハンドリングした際に角部に割れが発生し難い。よって、セルフレームの組み立て作業時などにおいて双極板の角部に割れが発生することを抑制でき、レドックスフロー電池の生産性を向上できる。また、双極板の平面視における角Ｒが１００ｍｍ以下であることで、双極板の幅方向の中央部と角部が設けられた端部とで電解液の流路長の差を小さくできる。したがって、双極板の中央部で電解液が過充電状態になり難く、過充電による電極などの損傷を抑制できるので、レドックスフロー電池の信頼性を向上できる。 According to the above bipolar plate, the curvature radius (corner R) of the corner when the bipolar plate is viewed in plan in the thickness direction is 5 mm or more, so that the corner is cracked when the bipolar plate is handled. hard. Therefore, it is possible to suppress the occurrence of cracks at the corners of the bipolar plate at the time of assembling the cell frame, and to improve the productivity of the redox flow battery. In addition, since the angle R in a plan view of the bipolar plate is 100 mm or less, the difference in the flow path length of the electrolyte can be reduced between the central portion in the width direction of the bipolar plate and the end portion provided with the corner portion. Therefore, the electrolyte is unlikely to be overcharged at the center of the bipolar plate, and damage to the electrodes and the like due to overcharge can be suppressed, so that the reliability of the redox flow battery can be improved.
　（２）上記双極板の一形態として、前記双極板の平面形状が矩形状であることが挙げられる。 (2) One form of the bipolar plate is that the planar shape of the bipolar plate is rectangular.
　双極板の平面形状（双極板を厚さ方向に平面視したときの形状）が矩形状であれば、互いに対向する両縁部が平行な直線状の辺部を有し、角部を除く幅方向中央部における電解液の流路長を幅方向に亘って実質的に一定にできる。よって、双極板における幅方向の中央部で過充電になることを抑制し易い。 If the planar shape of the bipolar plate (the shape when the bipolar plate is viewed in plan in the thickness direction) is a rectangular shape, both edges facing each other have parallel straight sides and the width excluding the corners The flow path length of the electrolyte solution in the central portion in the direction can be made substantially constant over the width direction. Therefore, it is easy to suppress overcharging at the center in the width direction of the bipolar plate.
　（３）実施形態に係るセルフレームは、上記（１）又は（２）に記載の双極板と、前記双極板の外周に設けられる枠体とを備える。 (3) A cell frame according to the embodiment includes the bipolar plate according to the above (1) or (2) and a frame body provided on an outer periphery of the bipolar plate.
　上記セルフレームによれば、上記した実施形態に係る双極板を備えることから、レドックスフロー電池の生産性及び信頼性の向上を図ることができる。 According to the cell frame, since the bipolar plate according to the above-described embodiment is provided, the productivity and reliability of the redox flow battery can be improved.
　（４）実施形態に係るセルスタックは、上記（３）に記載のセルフレームを備える。 (4) A cell stack according to the embodiment includes the cell frame described in (3) above.
　上記セルスタックによれば、上記した実施形態に係るセルフレームを備えることから、レドックスフロー電池の生産性及び信頼性の向上を図ることができる。 Since the cell stack includes the cell frame according to the above-described embodiment, the productivity and reliability of the redox flow battery can be improved.
　（５）実施形態に係るレドックスフロー電池は、上記（４）に記載のセルスタックを備える。 (5) A redox flow battery according to the embodiment includes the cell stack described in (4) above.
　上記レドックスフロー電池によれば、上記したセルスタックを備えることから、生産性に優れ、信頼性が高い。 According to the above redox flow battery, since it has the above-described cell stack, it has excellent productivity and high reliability.
　［本願発明の実施形態の詳細］
　本願発明の実施形態に係る双極板、セルフレーム、セルスタック、及びレドックスフロー電池（ＲＦ電池）の具体例を、以下に図面を参照しつつ説明する。図中の同一符号は同一又は相当部分を示す。なお、本願発明はこれらの例示に限定されるものではなく、請求の範囲によって示され、請求の範囲と均等の意味および範囲内でのすべての変更が含まれることが意図される。 [Details of the embodiment of the present invention]
Specific examples of the bipolar plate, the cell frame, the cell stack, and the redox flow battery (RF battery) according to the embodiment of the present invention will be described below with reference to the drawings. The same reference numerals in the drawings indicate the same or corresponding parts. In addition, this invention is not limited to these illustrations, is shown by the claim, and intends that all the changes within the meaning and range equivalent to a claim are included.
　《ＲＦ電池》
　図１～図３を主に参照して、実施形態に係るレドックスフロー電池（以下、ＲＦ電池）、セルスタック、及びセルフレームの一例を説明する。図１、図２に示すＲＦ電池１は、正極電解液及び負極電解液に酸化還元により価数が変化する金属イオンを活物質として含有する電解液を使用し、正極電解液に含まれるイオンの酸化還元電位と、負極電解液に含まれるイオンの酸化還元電位との差を利用して充放電を行う電池である。ここでは、ＲＦ電池１の一例として、図１に示すように、正極電解液及び負極電解液に活物質となるＶイオンを含有するバナジウム電解液を使用したバナジウム系ＲＦ電池の場合を示す。図１中のセル１００内の実線矢印は充電反応を、破線矢印は放電反応をそれぞれ示している。ＲＦ電池１は、電解液循環型の蓄電池の１つであって、例えば、負荷平準化用途、瞬低補償や非常用電源などの用途、大量導入が進められている太陽光や風力などの再生可能エネルギーの出力平滑化用途などに利用される。 << RF battery >>
An example of a redox flow battery (hereinafter referred to as an RF battery), a cell stack, and a cell frame according to the embodiment will be described mainly with reference to FIGS. The RF battery 1 shown in FIG. 1 and FIG. 2 uses an electrolytic solution containing, as an active material, a metal ion whose valence changes as a result of oxidation and reduction in the positive electrode electrolyte and the negative electrode electrolyte. The battery performs charging / discharging by utilizing the difference between the redox potential and the redox potential of ions contained in the negative electrode electrolyte. Here, as an example of the RF battery 1, as shown in FIG. 1, a case of a vanadium-based RF battery using a vanadium electrolyte solution containing V ions serving as an active material in a positive electrode electrolyte and a negative electrode electrolyte is shown. A solid line arrow in the cell 100 in FIG. 1 indicates a charging reaction, and a broken line arrow indicates a discharging reaction. The RF battery 1 is one of the electrolyte circulation type storage batteries. For example, applications such as load leveling, sag compensation, emergency power supply, etc., and regeneration of solar and wind power, which are being introduced in large quantities. Used for smoothing output of possible energy.
　ＲＦ電池１は、水素イオンを透過させる隔膜１０１で正極セル１０２と負極セル１０３とに分離されたセル１００を備える。正極セル１０２には正極電極１０４が内蔵され、かつ正極電解液を貯留する正極電解液用タンク１０６が導管１０８、１１０を介して接続されている。導管１０８には、正極電解液を正極セル１０２に圧送するポンプ１１２が設けられており、これらの部材１０６、１０８、１１０、１１２によって正極電解液を循環させる正極用循環機構１００Ｐが構成されている。同様に、負極セル１０３には負極電極１０５が内蔵され、かつ負極電解液を貯留する負極電解液用タンク１０７が導管１０９、１１１を介して接続されている。導管１０９には、負極電解液を負極セル１０３に圧送するポンプ１１３が設けられており、これらの部材１０７、１０９、１１１、１１３によって負極電解液を循環させる負極用循環機構１００Ｎが構成されている。各タンク１０６、１０７に貯留される各電解液は、充放電を行う運転時には、ポンプ１１２、１１３によりセル１００（正極セル１０２及び負極セル１０３）内に循環され、充放電を行わない待機時には、ポンプ１１２、１１３が停止され、循環されない。 The RF battery 1 includes a cell 100 separated into a positive electrode cell 102 and a negative electrode cell 103 by a diaphragm 101 that transmits hydrogen ions. A positive electrode 104 is built in the positive electrode cell 102, and a positive electrode electrolyte solution tank 106 for storing the positive electrode electrolyte is connected via conduits 108 and 110. The conduit 108 is provided with a pump 112 that pumps the positive electrode electrolyte to the positive electrode cell 102, and a positive electrode circulation mechanism 100 </ b> P that circulates the positive electrode electrolyte is constituted by these members 106, 108, 110, and 112. . Similarly, the negative electrode cell 103 contains a negative electrode 105 and is connected to a negative electrode electrolyte tank 107 for storing a negative electrode electrolyte via conduits 109 and 111. The conduit 109 is provided with a pump 113 for pumping the negative electrode electrolyte to the negative electrode cell 103, and a negative electrode circulation mechanism 100N for circulating the negative electrode electrolyte is constituted by these members 107, 109, 111, 113. . The electrolytes stored in the tanks 106 and 107 are circulated in the cell 100 (the positive electrode cell 102 and the negative electrode cell 103) by the pumps 112 and 113 at the time of charging and discharging, and at the time of standby without charging and discharging. Pumps 112 and 113 are stopped and not circulated.
　《セルスタック》
　セル１００は通常、図２、図３に示すセルスタック２と呼ばれる構造体の内部に形成される。セルスタック２は、サブスタック２００（図３参照）と呼ばれる積層体をその両側から２枚のエンドプレート２２０で挟み込み、両側のエンドプレート２２０を締付機構２３０で締め付けることで構成されている（図３に例示する構成では、複数のサブスタック２００を備える）。サブスタック２００は、セルフレーム３、正極電極１０４、隔膜１０１、及び負極電極１０５を複数積層してなり、その積層体の両端に給排板２１０（図３の下図参照、図２では省略）が配置された構成である。 《Cell stack》
The cell 100 is usually formed inside a structure called a cell stack 2 shown in FIGS. The cell stack 2 is configured by sandwiching a laminate called a sub stack 200 (see FIG. 3) from two sides with two end plates 220 and fastening the end plates 220 on both sides with a fastening mechanism 230 (see FIG. 3 includes a plurality of sub-stacks 200). The sub stack 200 is formed by stacking a plurality of cell frames 3, positive electrodes 104, diaphragms 101, and negative electrodes 105, and supply / discharge plates 210 (see the lower figure in FIG. 3, omitted in FIG. 2) at both ends of the laminated body. It is an arranged configuration.
　《セルフレーム》
　セルフレーム３は、図２、図３に示すように、正極電極１０４と負極電極１０５との間に配置される双極板３１と、双極板３１の外周に設けられる枠体３２とを備える。双極板３１の一面側には、正極電極１０４が接触するように配置され、双極板３１の他面側には、負極電極１０５が接触するように配置される。サブスタック２００（セルスタック２）では、隣接する各セルフレーム３の双極板３１の間にそれぞれ１つのセル１００が形成されることになる。 《Cell Frame》
As illustrated in FIGS. 2 and 3, the cell frame 3 includes a bipolar plate 31 disposed between the positive electrode 104 and the negative electrode 105, and a frame body 32 provided on the outer periphery of the bipolar plate 31. The positive electrode 104 is disposed on one surface side of the bipolar plate 31 and the negative electrode 105 is disposed on the other surface side of the bipolar plate 31. In the sub stack 200 (cell stack 2), one cell 100 is formed between the bipolar plates 31 of the adjacent cell frames 3 respectively.
　双極板３１は、例えば、プラスチックカーボンなどで形成され、枠体３２は、例えば、塩化ビニル樹脂（ＰＶＣ）、ポリプロピレン、ポリエチレン、フッ素樹脂、エポキシ樹脂などのプラスチックで形成されている。双極板３１は、例えば、射出成型、プレス成型、真空成型などの公知の方法によって成形することができる。 The bipolar plate 31 is made of, for example, plastic carbon, and the frame body 32 is made of, for example, plastic such as vinyl chloride resin (PVC), polypropylene, polyethylene, fluorine resin, or epoxy resin. The bipolar plate 31 can be formed by a known method such as injection molding, press molding, or vacuum molding.
　セル１００への電解液の流通は、給排板２１０（図３の下図参照）を介して、図３に示すセルフレーム３の枠体３２に貫通して設けられた給液マニホールド３３、３４及び排液マニホールド３５、３６と、枠体３２に形成された給液スリット３３ｓ、３４ｓ及び排液スリット３５ｓ、３６ｓにより行われる（図４も併せて参照）。この例に示すセルフレーム３（枠体３２）の場合、正極電解液は、枠体３２の下部に設けられた給液マニホールド３３から枠体３２の一面側（紙面表側）に形成された給液スリット３３ｓを介して正極電極１０４に供給され、枠体３２の上部に形成された排液スリット３５ｓを介して排液マニホールド３５に排出される。同様に、負極電解液は、枠体３２の下部に設けられた給液マニホールド３４から枠体３２の他面側（紙面裏側）に形成された給液スリット３４ｓを介して負極電極１０５に供給され、枠体３２の上部に形成された排液スリット３６ｓを介して排液マニホールド３６に排出される。双極板３１が設けられる枠体３２の内側の下縁部及び上縁部には、縁部に沿って整流部（図示せず）が形成されていてもよい。整流部は、給液スリット３３ｓ、３４ｓから供給される各電解液を各電極の下縁部に沿って拡散させたり、各電極の上縁部から排出される各電解液を排液スリット３５ｓ、３６ｓへ集約する機能を有する。 The electrolyte solution flows into the cell 100 through supply / discharge plates 210 (see the lower diagram in FIG. 3), and supply manifolds 33, 34 provided through the frame body 32 of the cell frame 3 shown in FIG. This is performed by the drainage manifolds 35 and 36, the liquid supply slits 33s and 34s formed in the frame 32, and the drainage slits 35s and 36s (see also FIG. 4). In the case of the cell frame 3 (frame body 32) shown in this example, the positive electrode electrolyte is supplied from the liquid supply manifold 33 provided at the lower part of the frame body 32 on the one surface side (the paper surface side) of the frame body 32. It is supplied to the positive electrode 104 through the slit 33 s and discharged to the drainage manifold 35 through the drainage slit 35 s formed in the upper part of the frame 32. Similarly, the negative electrode electrolyte is supplied to the negative electrode 105 from a liquid supply manifold 34 provided in the lower part of the frame 32 through a liquid supply slit 34 s formed on the other surface side (back side of the paper) of the frame 32. The liquid is discharged to the drainage manifold 36 through the drainage slit 36s formed in the upper part of the frame 32. A rectifying portion (not shown) may be formed along the edge at the lower edge and the upper edge inside the frame 32 on which the bipolar plate 31 is provided. The rectifying unit diffuses each electrolytic solution supplied from the liquid supply slits 33 s and 34 s along the lower edge portion of each electrode, or discharges each electrolytic solution discharged from the upper edge portion of each electrode to the drain slits 35 s, It has the function of consolidating to 36s.
　この例では、双極板３１の下側から電解液が供給され、双極板３１の上側から電解液が排出されるようになっており、双極板３１の下縁部から上縁部に向かって電解液が流れる。図４中、紙面左側の太線矢印は、双極板３１における電解液の全体的な電解液の流通方向を示す。双極板３１の各電極と接する表面には、電解液の流通方向に沿って複数の溝部（図示せず）が形成されていてもよい。これにより、電解液の流通抵抗を小さくでき、電解液の圧力損失を低減できる。溝部の断面形状（電解液の流通方向に直交する断面の形状）は、特に限定されず、例えば、矩形状、三角形状（Ｖ字状）、台形状、半円形状や半楕円形状などが挙げられる。 In this example, the electrolytic solution is supplied from the lower side of the bipolar plate 31 and is discharged from the upper side of the bipolar plate 31, and electrolysis is performed from the lower edge portion of the bipolar plate 31 toward the upper edge portion. Liquid flows. In FIG. 4, a thick line arrow on the left side of the drawing indicates an overall electrolyte flow direction of the electrolyte solution in the bipolar plate 31. A plurality of grooves (not shown) may be formed on the surface of the bipolar plate 31 in contact with each electrode along the flow direction of the electrolytic solution. Thereby, the distribution | circulation resistance of electrolyte solution can be made small and the pressure loss of electrolyte solution can be reduced. The cross-sectional shape of the groove (the cross-sectional shape orthogonal to the flow direction of the electrolyte) is not particularly limited, and examples thereof include a rectangular shape, a triangular shape (V shape), a trapezoidal shape, a semicircular shape, and a semielliptical shape. It is done.
　その他、各セルフレーム３の枠体３２の間には、セル１００からの電解液の漏洩を抑制するため、Ｏリングや平パッキンなどの環状のシール部材３７（図２、図３参照）が配置されている。枠体３２には、シール部材３７を配置するためのシール溝３８（図４参照）が形成されている。 In addition, an annular seal member 37 (see FIGS. 2 and 3) such as an O-ring and a flat packing is disposed between the frame bodies 32 of each cell frame 3 in order to suppress leakage of the electrolyte from the cell 100. Has been. A seal groove 38 (see FIG. 4) for arranging the seal member 37 is formed in the frame body 32.
　実施形態に係る双極板３１の特徴の１つは、双極板３１を平面視したときの角部の曲率半径（角Ｒ）が５ｍｍ以上１００ｍｍ以下である点にある。以下、図４～図６を主に参照して、実施形態に係る双極板３１、及びセルフレーム３の構成の一例を詳しく説明する。 One of the features of the bipolar plate 31 according to the embodiment is that the radius of curvature (corner R) of the corner when the bipolar plate 31 is viewed in plan is 5 mm or more and 100 mm or less. Hereinafter, an example of the configuration of the bipolar plate 31 and the cell frame 3 according to the embodiment will be described in detail with reference mainly to FIGS.
　《双極板》
　双極板３１は、図５に示すように、平面視したときに角部４０を有する形状である。この例では、双極板３１の平面形状が４つの角部４１～４４を有する矩形状であり、双極板３１における互いに対向する下縁部及び上縁部が平行な直線状の辺部４５、４６を有する。双極板３１は、平面視における角部４０が丸く形成されており、各角部４１～４４の曲率半径（角Ｒ）が５ｍｍ以上１００ｍｍ以下である。双極板３１のサイズは、例えば、縦方向（図５の紙面上下方向）の長さが２００ｍｍ以上２０００ｍｍ以下、幅方向（図５の紙面左右方向）の長さが２００ｍｍ以上２０００ｍｍ以下、厚さが３．０ｍｍ以上１０．０ｍｍ以下である。 《Dipolar plate》
As shown in FIG. 5, the bipolar plate 31 has a shape having a corner 40 when viewed in plan. In this example, the planar shape of the bipolar plate 31 is a rectangular shape having four corners 41 to 44, and the lower and upper edges of the bipolar plate 31 that are opposite to each other are straight side portions 45 and 46 that are parallel to each other. Have The bipolar plate 31 has round corners 40 in plan view, and the radius of curvature (corner R) of each of the corners 41 to 44 is not less than 5 mm and not more than 100 mm. As for the size of the bipolar plate 31, for example, the length in the vertical direction (up and down direction in FIG. 5) is 200 mm or more and 2000 mm or less, the length in the width direction (left and right direction in FIG. 5) is 200 mm or more and 2000 mm or less, and the thickness is It is 3.0 mm or more and 10.0 mm or less.
　図４に示すように、双極板３１の外周に枠体３２が設けられることで、セルフレーム３が構成される。枠体３２は、図５に示すように、その内側に開口部５０が形成されており、開口部５０に双極板３１が配置される。この例では、枠体３２が矩形枠状であり、開口部５０は双極板３１の外形に対応した形状に形成されている。つまり、開口部５０の形状が双極板３１の平面形状と実質的に同じ形状（相似形状）であり、開口部５０が形成される枠体３２の内周縁部の角部が、双極板３１の角部４０と同じように丸く形成され、双極板３１と略同じ角Ｒを有する。枠体３２の内周縁部には、双極板３１の外周縁部と接する段差部５１が形成されており、図６に示すように、双極板３１の外周縁部が段差部５１に配置されることによって、双極板３１が枠体３２に支持される。双極板３１の外周縁部には、段差部５１と接する面に周方向に沿って溝が形成され、その溝にシール部材５２が配置されている。このシール部材５２によって、双極板３１の一面側と他面側との間で電解液が移動することを抑制できる。 As shown in FIG. 4, the cell frame 3 is configured by providing a frame 32 on the outer periphery of the bipolar plate 31. As shown in FIG. 5, the frame 32 has an opening 50 formed therein, and the bipolar plate 31 is disposed in the opening 50. In this example, the frame body 32 has a rectangular frame shape, and the opening 50 is formed in a shape corresponding to the outer shape of the bipolar plate 31. That is, the shape of the opening 50 is substantially the same shape (similar shape) as the planar shape of the bipolar plate 31, and the corner of the inner peripheral edge of the frame 32 where the opening 50 is formed is Like the corner 40, it is rounded and has substantially the same corner R as the bipolar plate 31. A stepped portion 51 in contact with the outer peripheral edge of the bipolar plate 31 is formed at the inner peripheral edge of the frame 32, and the outer peripheral edge of the bipolar plate 31 is disposed at the stepped portion 51 as shown in FIG. 6. Thus, the bipolar plate 31 is supported by the frame body 32. A groove is formed in the outer peripheral edge portion of the bipolar plate 31 along the circumferential direction on the surface in contact with the stepped portion 51, and a seal member 52 is disposed in the groove. The seal member 52 can suppress the electrolyte solution from moving between the one surface side and the other surface side of the bipolar plate 31.
　枠体３２の開口部５０に双極板３１を配置してセルフレーム３を構成した場合、図４に示すように、双極板３１の表面及び枠体３２の内周面により枠体３２の内側に凹部５５が形成される。凹部５５は、図６に示すように、双極板３１の両側にそれぞれ形成され、各凹部５５に正極電極１０４及び負極電極１０５がそれぞれ収納される。各電極１０４、１０５は、各凹部５５と略同じサイズに形成されている。図４に示すセルフレーム３の場合、一面側に設けられた凹部５５の形状が双極板３１の平面形状と実質的に同じ形状であり、この凹部５５に収納される正極電極１０４（図６参照）の形状が双極板３１の平面形状と実質的に同じ形状である。セルフレーム３に各電極１０４、１０５を配置し、セルフレーム３を隔膜１０１を介して積層することで、セルスタック２（図３参照）が構成される。 When the cell plate 3 is configured by arranging the bipolar plate 31 in the opening 50 of the frame 32, the surface of the bipolar plate 31 and the inner peripheral surface of the frame 32 are placed inside the frame 32 as shown in FIG. 4. A recess 55 is formed. As shown in FIG. 6, the concave portions 55 are formed on both sides of the bipolar plate 31, and the positive electrode 104 and the negative electrode 105 are respectively stored in the concave portions 55. Each of the electrodes 104 and 105 is formed in substantially the same size as each of the recesses 55. In the case of the cell frame 3 shown in FIG. 4, the shape of the recess 55 provided on one surface side is substantially the same as the planar shape of the bipolar plate 31, and the positive electrode 104 accommodated in the recess 55 (see FIG. 6). ) Is substantially the same as the planar shape of the bipolar plate 31. The electrodes 104 and 105 are arranged on the cell frame 3, and the cell frame 3 is laminated via the diaphragm 101, whereby the cell stack 2 (see FIG. 3) is configured.
　｛作用効果｝
　実施形態に係る双極板３１は、次の作用効果を奏する。
　双極板３１の平面視における角部４０が丸く形成され、角Ｒが５ｍｍ以上であることで、角部４０に割れが発生することを抑制できる。そのため、セルフレーム３の組み立て作業時など、双極板３１をハンドリングした際に角部４０に割れが生じ難い。角部４０の割れを抑制する観点から、角Ｒは、例えば１０ｍｍ以上とすることが挙げられる。 {Function and effect}
The bipolar plate 31 according to the embodiment has the following operational effects.
Since the corner portion 40 in the plan view of the bipolar plate 31 is formed in a round shape and the corner R is 5 mm or more, it is possible to prevent the corner portion 40 from being cracked. Therefore, when the bipolar plate 31 is handled at the time of assembling the cell frame 3 or the like, the corner portion 40 is hardly cracked. From the viewpoint of suppressing cracking of the corner portion 40, the corner R is, for example, 10 mm or more.
　双極板３１を用いてセルフレーム３を構成した場合、図４に示すように、双極板３１の下縁部から上縁部に向かって電解液が流れる際、幅方向の両端部（角部４１、４２間の領域及び角部４３、４４間の領域）と、幅方向の中央部（辺部４５、４６間の領域）とで電解液の流路長が異なる。そして、双極板３１の幅方向中央部における流路長Ｌ２が両端部における流路長Ｌ１よりも長くなる（Ｌ２＞Ｌ１）。双極板３１の幅方向中央部における流路長Ｌ２は幅方向に亘って一定である。本例の双極板３１では、角Ｒが１００ｍｍ以下に設定され、幅方向の中央部での流路長Ｌ２と両端部での流路長Ｌ１との差が一定の範囲内になるように設定されている。角Ｒが１００ｍｍ以下であり、双極板の３１幅方向の中央部と両端部とで電解液の流路長の差が小さいため、中央部で電解液の流路長が長くなることに起因する電解液の過充電を抑制できる。そのため、電解液の過充電による熱の発生に伴う電極の酸化損傷や隔膜の損傷を抑制できる。過充電による電極などの損傷を抑制する観点から、角Ｒは、例えば５０ｍｍ以下とすることが挙げられる。最大となる流路長Ｌ２と最小となる流路長Ｌ１との比（Ｌ２／Ｌ１）は、例えば１．５以下、１．３以下、更に１．１以下とすることが挙げられる。 When the cell frame 3 is configured using the bipolar plate 31, as shown in FIG. 4, when the electrolyte flows from the lower edge portion to the upper edge portion of the bipolar plate 31, both end portions (corner portions 41) in the width direction. , 42 and the region between the corners 43, 44) and the central portion in the width direction (region between the side portions 45, 46) are different in the flow path length of the electrolyte. And the flow path length L2 in the width direction center part of the bipolar plate 31 becomes longer than the flow path length L1 in both ends (L2> L1). The flow path length L2 at the center in the width direction of the bipolar plate 31 is constant over the width direction. In the bipolar plate 31 of this example, the angle R is set to 100 mm or less, and the difference between the flow path length L2 at the center in the width direction and the flow path length L1 at both ends is set within a certain range. Has been. This is because the angle R is 100 mm or less, and the difference in the flow path length of the electrolyte solution between the central portion and both end portions in the 31 width direction of the bipolar plate is small. Electrolytic overcharge can be suppressed. Therefore, it is possible to suppress oxidative damage of the electrode and damage to the diaphragm accompanying heat generation due to overcharging of the electrolytic solution. From the viewpoint of suppressing damage to electrodes and the like due to overcharge, the angle R is, for example, 50 mm or less. The ratio (L2 / L1) between the maximum flow path length L2 and the minimum flow path length L1 is, for example, 1.5 or less, 1.3 or less, and further 1.1 or less.
　［試験例１］
　平面形状が矩形状の双極板を用意した。双極板のサイズ（外形寸法）は、縦２５０ｍｍ×幅６００ｍｍ×厚さ１０．０ｍｍである。ここでは、表１に示すように、平面視における角部の曲率半径（角Ｒ）が異なる複数の双極板（図５参照）を用意した。各双極板を用いてセルフレーム（図４参照）を作製し、これを用いて複数のＲＦ電池（試験体Ａ～Ｇ）を組み立てた。そして、各試験体について、生産性及び信頼性を評価した。 [Test Example 1]
A bipolar plate having a rectangular planar shape was prepared. The size (outside dimension) of the bipolar plate is 250 mm long × 600 mm wide × 10.0 mm thick. Here, as shown in Table 1, a plurality of bipolar plates (see FIG. 5) having different corner radii of curvature (angles R) in plan view were prepared. A cell frame (see FIG. 4) was prepared using each bipolar plate, and a plurality of RF batteries (test bodies A to G) were assembled using the cell frame. And about each test body, productivity and reliability were evaluated.
　生産性の評価は、各双極板を１００個用意してセルフレームを作製したときに、双極板の角部に割れが発生したどうかを目視で確認した。そして、１００個中、全てで角部に割れがない場合を「Ａ」、角部に割れが発生した個数が５個未満の場合を「Ｂ」、それ以上の場合を「Ｃ」として評価した。その結果を表１に示す。 Evaluation of productivity was made by visually checking whether or not cracks occurred at the corners of the bipolar plate when 100 cell plates were prepared with each bipolar plate. And in 100 pieces, the case where there was no crack in the corner portion was evaluated as “A”, the case where the number of cracks generated in the corner portion was less than 5, “B”, and the case where it was more than “C” was evaluated. . The results are shown in Table 1.
　信頼性の評価は、各試験体Ａ～Ｇに対して充放電試験を行った後、ＲＦ電池を解体して電極を取り出し、電極の酸化損傷の程度を確認した。充放電試験の条件は、放電終了電圧：１Ｖ、充電終了電圧：１．６Ｖ、電流：１２０ｍＡ／ｃｍ２、３００サイクルとした。そして、酸化損傷がない場合を「Ａ」、酸化損傷の程度が小さく、使用上問題がない場合を「Ｂ」、酸化損傷によるダメージが大きい場合を「Ｃ」として評価した。その結果を表１に示す。 In the evaluation of reliability, after performing charge / discharge tests on each of the test bodies A to G, the RF battery was disassembled and the electrode was taken out to confirm the degree of oxidative damage of the electrode. The conditions for the charge / discharge test were: discharge end voltage: 1 V, charge end voltage: 1.6 V, current: 120 mA / cm 2 , 300 cycles. The case where there was no oxidative damage was evaluated as “A”, the case where the degree of oxidative damage was small and no problem in use was evaluated as “B”, and the case where damage due to oxidative damage was large was evaluated as “C”. The results are shown in Table 1.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
　表１に示す結果から、双極板の角Ｒが５ｍｍ以上であれば、双極板の角部の割れを抑制でき、特に、角Ｒが１０ｍｍ以上である場合、角部の割れを効果的に抑制できることが確認できた。また、双極板の角Ｒが１００ｍｍ以下であれば、電極の酸化損傷を抑制でき、特に、角Ｒが５０ｍｍ以下の場合、電極の酸化損傷を効果的に抑制できることが確認できた。したがって、双極板の角Ｒが５ｍｍ以上１００ｍｍ以下、特に１０ｍｍ以上５０ｍｍ以下である場合、ＲＦ電池の生産性及び信頼性を改善できる。 From the results shown in Table 1, if the angle R of the bipolar plate is 5 mm or more, cracks at the corners of the bipolar plate can be suppressed. In particular, if the angle R is 10 mm or more, cracks at the corners are effectively suppressed. I was able to confirm that it was possible. Further, it was confirmed that when the angle R of the bipolar plate is 100 mm or less, the oxidative damage of the electrode can be suppressed, and particularly when the angle R is 50 mm or less, the oxidative damage of the electrode can be effectively suppressed. Therefore, when the angle R of the bipolar plate is 5 mm to 100 mm, particularly 10 mm to 50 mm, the productivity and reliability of the RF battery can be improved.
　１　レドックスフロー電池（ＲＦ電池）
　２　セルスタック
　３　セルフレーム
　３１　双極板
　３２　枠体
　３３、３４　給液マニホールド
　３５、３６　排液マニホールド
　３３ｓ、３４ｓ　給液スリット
　３５ｓ、３６ｓ　排液スリット
　３７　シール部材
　３８　シール溝
　４０、４１、４２、４３、４４　角部
　４５、４６　辺部
　５０　開口部
　５１　段差部
　５２　シール部材
　５５　凹部
　１００　セル
　１０１　隔膜
　１０２　正極セル
　１０３　負極セル
　１００Ｐ　正極用循環機構
　１００Ｎ　負極用循環機構
　１０４　正極電極
　１０５　負極電極
　１０６　正極電解液用タンク
　１０７　負極電解液用タンク
　１０８、１０９、１１０、１１１　導管
　１１２、１１３　ポンプ
　２００　サブスタック
　２１０　給排板
　２２０　エンドプレート
　２３０　締付機構 1 Redox flow battery (RF battery)
2 cell stack 3 cell frame 31 bipolar plate 32 frame 33, 34 liquid supply manifold 35, 36 liquid discharge manifold 33s, 34s liquid supply slit 35s, 36s liquid discharge slit 37 seal member 38 seal groove 40, 41, 42, 43, 44 Corner portion 45, 46 Side portion 50 Opening portion 51 Step portion 52 Seal member 55 Recessed portion 100 Cell 101 Diaphragm 102 Positive electrode cell 103 Negative electrode cell 100P Positive electrode circulation mechanism 100N Negative electrode circulation mechanism 104 Positive electrode 105 Negative electrode 106 Positive electrode electrolyte Tank 107 Anode for negative electrode electrolyte 108, 109, 110, 111 Conduit 112, 113 Pump 200 Sub stack 210 Supply / discharge plate 220 End plate 230 Tightening mechanism

Claims (5)

  1. 　レドックスフロー電池の電極が配置される双極板であって、
    　前記双極板を平面視したときの角部の曲率半径が５ｍｍ以上１００ｍｍ以下である双極板。     A bipolar plate on which electrodes of a redox flow battery are arranged,
    A bipolar plate having a radius of curvature of a corner portion of 5 mm or more and 100 mm or less when the bipolar plate is viewed in plan.
  2. 　前記双極板の平面形状が矩形状である請求項１に記載の双極板。 The bipolar plate according to claim 1, wherein a planar shape of the bipolar plate is rectangular.
  3. 　請求項１又は請求項２に記載の双極板と、前記双極板の外周に設けられる枠体とを備えるセルフレーム。 A cell frame comprising the bipolar plate according to claim 1 or 2 and a frame provided on an outer periphery of the bipolar plate.
  4. 　請求項３に記載のセルフレームを備えるセルスタック。 A cell stack comprising the cell frame according to claim 3.
  5. 　請求項４に記載のセルスタックを備えるレドックスフロー電池。 A redox flow battery comprising the cell stack according to claim 4.
PCT/JP2017/001614 2017-01-18 2017-01-18 Bipolar plate, cell frame, cell stack, and redox flow cell WO2018134927A1 (en)

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2002246061A (en) * 2001-02-15 2002-08-30 Sumitomo Electric Ind Ltd Cell frame structure for redox flow secondary cell, and manufacturing method therefor
JP2002260600A (en) * 2001-02-28 2002-09-13 Tdk Corp Electrochemical device
JP2005228622A (en) * 2004-02-13 2005-08-25 Sumitomo Electric Ind Ltd Redox flow battery cell
WO2009139389A1 (en) * 2008-05-15 2009-11-19 株式会社アルバック Thin film solar battery module manufacturing method and thin film solar battery module

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2002246061A (en) * 2001-02-15 2002-08-30 Sumitomo Electric Ind Ltd Cell frame structure for redox flow secondary cell, and manufacturing method therefor
JP2002260600A (en) * 2001-02-28 2002-09-13 Tdk Corp Electrochemical device
JP2005228622A (en) * 2004-02-13 2005-08-25 Sumitomo Electric Ind Ltd Redox flow battery cell
WO2009139389A1 (en) * 2008-05-15 2009-11-19 株式会社アルバック Thin film solar battery module manufacturing method and thin film solar battery module

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