Cell stacks and redox flow batteries

Abstract

To enable a cost reduction and a reduction in number of components.SOLUTION: A cell stack 100 comprises a plurality of battery cells 110 composed of: a positive electrode 101 and a negative electrode 102; a barrier membrane 103 arranged between the positive electrode 101 and the negative electrode 102; an electrode distribution part 105 in which the positive electrode 101 and a negative electrode 103 are arranged on both sides; and a cell frame 1 composed of a frame body 5 provided at the circumference of the electrode distribution part 105 are stacked. In the cell stack 100, a pair of end plates 120A and 120B are arranged on both side end parts in a stack direction of each of the plurality of staked battery cells 110. A stack 130 composed of the plurality of stacked battery cells 110 and the pair of end plates 120A and 120B arranged at both side end part in the stack direction are integrally sealed by a resin formation part 140 formed at the circumference.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a cell stack formed by laminating electrolytic cells which are output parts of a battery, and a redox flow battery using the same. In particular, the present invention relates to a cell stack capable of reducing the number of components and reducing costs, and a redox flow battery using the same.

Background Art

[0002] In recent years, due to the suppression of global warming and the protection of the global environment, interest in power generation technologies using renewable natural energy such as solar power generation and wind power generation has rapidly increased and their introduction has been promoted. In such power generation methods, output fluctuations occur, so power storage technology (energy storage technology) has attracted attention as a technology for absorbing the output fluctuations and stabilizing the power grid. And a redox flow battery is known as one of the energy storage devices. A redox flow battery is a storage battery that circulates an electrolytic solution in which an active material is dissolved in a solvent by a pump and performs charge and discharge by the oxidation-reduction reaction of ions in the electrolytic solution. Although the electrodes and the electrolytic solution have a long life and high safety, low cost is desired for its widespread use.

[0003] In this redox flow battery, in order to obtain a predetermined voltage, it generally has a configuration of a cell stack in which a plurality of battery cells (single cells) are laminated. Roughly speaking, a positive electrode and a negative electrode are arranged between adjacent cell frames via a separator to form one battery cell (single cell), and a plurality of such single cells are laminated to form a cell stack. And on the positive electrode side of the battery cell of the cell stack, a positive electrode electrolytic solution is supplied from a positive electrode electrolytic solution tank storing the positive electrode electrolytic solution, and on the negative electrode side, a negative electrode electrolytic solution is supplied from a negative electrode electrolytic solution tank storing the negative electrode electrolytic solution. Charge and discharge are performed by simultaneously advancing an oxidation reaction and a reduction reaction on the positive and negative electrodes. At this time, the positive and negative electrolytic solutions are circulated between the electrolytic solution tank and the battery cell using a circulation pump.

[0004] Conventionally, a cell stack of a redox flow battery is known to be assembled by stacking battery cells, each cell consisting of a diaphragm located in the center of the stacking direction, positive and negative electrodes placed on either side thereof, and a bipolar plate placed between the positive and negative electrodes. At both ends in the stacking direction, current collector plates and supply / drain plates equipped with electrolyte supply and drain pipes are placed, and metal pressure plates (retaining plates) are placed on both sides thereof. Multiple long bolts are passed through the opposing pressure plates and tightened with metal nuts or other fasteners.

[0005] In conventional cell stacks, electrolyte leakage is prevented by sealing the spaces between adjacent cell frames by interposing an annular sealing member, such as an O-ring or flat packing, between each cell frame and diaphragm. For example, Patent Document 1 discloses a cell frame technology for an electrolyte-flow type battery, comprising a bipolar plate, a frame having an inner peripheral edge positioned opposite to the outer peripheral edge of the bipolar plate, and an annular sealing material interposed between the outer peripheral edge of the bipolar plate and the inner peripheral edge of the frame, and used in a state where it is pressed between the bipolar plate and the frame.

[0006] Furthermore, Patent Document 2 describes a frame joining structure for joining the frames of adjacent cell frames to form a region that will become a battery cell inside the frame, comprising a conductive member arranged in an annular manner along the circumferential direction of the frame between the frames, and a fusion layer adjacent to the conductive member and composed of a part of the frame, wherein the fusion layer joins the adjacent frames together and seals the inner region of each frame, and a method of welding the cell frames together is also proposed to prevent leakage of electrolyte. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2018-006194 [Patent Document 2] Japanese Patent Publication No. 2012-104237 [Overview of the Initiative] [Problems that the invention aims to solve]

[0008] However, as shown in Patent Document 1, conventional methods that seal the cell frames of a cell stack by interposing a sealing member between them result in a large number of parts and assembly steps. Furthermore, precision is required in the placement of the sealing member to ensure sealing performance, making the assembly of the cell stack time-consuming. In addition, the presence of a sealing member between the cell frames adds thickness. Moreover, there are concerns about a decrease in sealing performance due to aging of the sealing member, deformation such as twisting caused by changes in internal pressure and temperature of the electrolyte during charging and discharging within the cell stack, or rupture.

[0009] On the other hand, even with the frame joining structure presented in Patent Document 2, when joining frames by fusion, it is necessary to place conductive members between the frames, which increases the number of parts and man-hours. Furthermore, considering the reliable sealing performance provided by the fusion layer, precision is required in the placement and assembly of the conductive members. In addition, in the case of forming the fusion layer of the frame by heat generated by current, as in Patent Document 2, excess material (burrs) is likely to occur at the welded portion, making it difficult to control the uniformity of the welding. Moreover, welding between cell frames adds to the thickness. In addition, since the opposing surfaces of the cell frames are partially welded, stress caused by thermal expansion of the cell frame due to the internal pressure of the electrolyte and the temperature rise inside the cell stack during charging and discharging, when the electrolyte is circulated in the cell stack, can put a load on the welded area, making it prone to cracks, etc., which may lead to electrolyte leakage to the outside or contact between the positive and negative electrode electrolytes.

[0010] Therefore, the present invention aims to provide a cell stack and a redox flow battery that can reduce the number of parts and thus reduce costs. [Means for solving the problem]

[0011] The cell stack of the invention of claim 1 comprises a plurality of battery cells, each consisting of positive and negative electrodes, a diaphragm disposed between the positive and negative electrodes, and a cell frame on which the positive and negative electrodes are arranged, and a pair of end plates disposed at both ends in the stacking direction in which the plurality of battery cells are stacked, and the stack consisting of the plurality of stacked battery cells and the pair of end plates disposed at both ends in the stacking direction is surrounded and sealed integrally by a resin molding portion.

[0012] Here, the cell frame described above has positive and negative electrodes arranged on it, and a channel is formed for circulating the electrolyte supplied to the electrodes. Typically, the entire structure is roughly rectangular and is made of materials such as polyvinyl chloride, polypropylene, or polyethylene. The above-mentioned end plates are positioned at both ends in the stacking direction of a stack of battery cells, each cell consisting of positive and negative electrodes, a diaphragm placed between the positive and negative electrodes, and a cell frame on which the positive and negative electrodes are arranged. For example, they can be formed from resins such as polyvinyl chloride, polypropylene, or polyethylene, similar to the cell frame, or they can be formed by insert molding a current collector, giving it the function of a current collector.

[0013] The resin-formed portion is formed on the periphery of a laminate consisting of multiple stacked battery cells and a pair of end plates positioned at both ends in the stacking direction, enclosing the laminate and sealing the spaces between the layers. For example, it is formed by injection molding, in which liquid resin is filled and injected into a mold in which the laminate is placed, so as to enclose the periphery of the laminate and tightly bond it. This resin-formed portion is not required to enclose all six periphery surfaces of the laminate which is roughly shaped like a rectangular parallelepiped, but rather to cover at least all four periphery surfaces, excluding the two surfaces on both sides in the stacking direction where the cell frames and end plates are stacked in the thickness direction, thereby sealing the laminate as a whole.

[0014] Claim 1The resin forming portion of the cell stack of the invention has resin through holes provided in the cell frame and groove-shaped resin channels provided on the surface of the cell frame that connect the resin through holes to the outside of the cell frame, and a resin filling portion filled in resin through holes provided in the end plate and groove-shaped resin channels provided on the surface of the end plate that connect the resin through holes to the outside of the end plate.

[0015] The resin through-holes provided in the cell frame described above are through which liquid resin flows and fills to form a resin-forming section that surrounds and seals the laminate, and their position, number, and shape are not particularly limited. The resin channels provided on the cell frame surface are formed on one or both sides of the front and back of the cell frame, connecting the resin through-holes to the outside of the cell frame, and allowing the liquid resin flowing through the resin through-holes to flow to the outside of the cell frame. Liquid resin for forming the resin molding section flows through and fills these channels, and their shape is not particularly limited. The resin through-holes provided in the end plate correspond to the resin through-holes provided in the cell frame, and liquid resin flows through and fills them to form a resin-forming section that surrounds and seals the laminate. Their position, number, and shape are not particularly limited. The resin channel provided on the end plate surface is formed on one or both sides of the front and back of the cell frame, connecting the resin through-hole to the outside of the end plate, and allowing the liquid resin flowing through the resin through-hole to flow to the outside of the end plate. Liquid resin for forming the resin molding section flows through and fills the channel, and its shape is not particularly limited.

[0016] The resin-filled section is formed integrally with the resin-forming section surrounding the laminate, and is located in the resin through-holes and resin channels provided in the cell frame and end plate. This resin-filled section is formed by providing resin through-holes and resin channels within the cell frame and end plate for circulating liquid resin, injecting and filling liquid resin through the resin through-holes in the end plate of the laminate within the mold, and allowing the liquid resin to spread to the outer circumference of the cell frame and end plate through the resin through-holes and resin channels in the end plate and the cell frame. As a result, the resin through-holes and resin channels provided in the cell frame and end plate are filled with liquid resin, integrally with the resin-forming section formed on their outer circumference.

[0017] Claim 2 The cell stack of the invention has a cell frame having a manifold and an electrolyte flow path through which an electrolyte flows, and a resin-filled portion filled in the resin flow path of the cell frame is located between the manifold and the electrolyte flow path of the cell frame, and an end plate having a through hole and an electrolyte flow path through which an electrolyte flows, and a resin-filled portion filled in the resin flow path of the end plate is located between the through hole and the electrolyte flow path of the end plate, and the resin-filled portion is formed between the manifold and the through hole and the electrolyte flow path formed in the cell frame and the end plate.

[0018] Claim 3 The resin forming portion of the cell stack of the invention has a cylindrical resin forming opening formed on the outer surface side of the end plate through which the electrolyte is supplied and drained. The resin forming portion is formed on the outer surface sides on both sides in the stacking direction of the laminate, that is, on the side opposite to the self-frame facing surface side of the end plate, corresponding to the positions of the through holes formed in the end plate through which the electrolytic solution flows and the manifolds formed in the self-frame through which the electrolytic solution flows. Pipes for supplying the electrolytic solution supplied from an electrolytic solution tank that stores the electrolytic solution to the cell stack by a pump and pipes for sending and discharging the electrolytic solution from the cell stack to the electrolytic solution tank are connected thereto, and the electrolytic solution is supplied from the outside and discharged to the outside.

[0019] Claim 4 The resin forming portion of the cell stack according to the invention of claim has an annular resin forming end portion formed on the peripheral portion on the outer surface side of the end plate. The resin forming end portion is formed on the outer surface sides on both sides in the stacking direction of the laminate, that is, on the side opposite to the self-frame facing surface side of the end plate, and is formed annularly on the peripheral portion on the outer surface side of the end plate by the liquid resin for forming the resin forming portion flowing in from the outer periphery of the end plate toward the outer surface side.

[0020] Claim 5 The resin forming end portion of the resin forming portion of the cell stack according to the invention of claim has a resin engaging portion that engages with the end plate on the outer surface side of the end plate. The resin engaging portion is provided, for example, with an annular groove portion on the peripheral portion of the outer surface of the end plate, and the liquid resin for forming the resin forming portion flows into the groove portion provided on the outer surface side of the end plate from the outer periphery of the end plate and is filled therein to engage with the end plate.

[0021] Claim 6The redox flow battery of the invention is composed of a plurality of stacked battery cells, each battery cell being composed of a positive and a negative electrode, a separator disposed between the positive and negative electrodes, and a self-frame on which the positive and negative electrodes are disposed. A pair of end plates are arranged at both end portions in the stacking direction, and the cell stack has a resin forming portion that surrounds and integrally seals a laminate composed of the plurality of stacked battery cells and the pair of end plates arranged at both end portions in the stacking direction.

Advantages of the Invention

[0022] According to the cell stack according to the invention of claim 1, a plurality of battery cells composed of a positive and a negative electrode, a separator disposed between the positive and negative electrodes, and a self-frame on which the positive and negative electrodes are disposed are stacked, and a pair of end plates are arranged at both end portions in the stacking direction of the battery cells. By integrally surrounding the periphery of the laminate, that is, the outer periphery of the stacked self-frames and end plates, with a resin forming portion, the laminate is collectively sealed by the resin forming portion.

[0023] Therefore, the outer periphery of the stacked self-frames and end plates is integrally surrounded by a resin forming portion and collectively sealed, and components such as a seal member disposed between the self-frame surfaces and an energizing member for welding can be omitted, thereby reducing the number of components and the number of man-hours. Thus, cost reduction can be achieved.

[0024] Claim 1 According to the cell stack according to the invention of claim, the resin forming portion has resin through-holes provided in the self-frame, groove-shaped resin flow paths provided in the self-frame that communicate the resin through-holes with the outside of the self-frame, resin through-holes provided in the end plate, and resin filling portions filled in groove-shaped resin flow paths provided in the end plate that communicate the resin through-holes with the outside of the end plate. Therefore , se It is possible to prevent displacement and deformation of the self-frame and end plate, and prevent mixing and leakage of positive and negative electrolytes due to displacement and deformation of the self-frame and end plate.

[0025] Claim 2 According to the cell stack of the invention, the resin-filled portion that fills the resin channel of the cell frame is located between the manifold of the cell frame and the electrolyte channel, and the resin-filled portion that fills the resin channel of the end plate is located between the through-hole of the end plate and the electrolyte channel. Therefore, even if electrolyte spills out of the manifold in the cell frame, the step between the resin-filled portion and the cell frame surface prevents it from mixing with electrolyte of the opposite polarity to its positive and negative polarity. Similarly, in the end plate, even if electrolyte spills out of the through-hole, the step between the resin-filled portion and the end plate surface prevents it from mixing with electrolyte of the opposite polarity to its positive and negative polarity. Thus, in addition to the effects described in claim 1, a decrease in battery capacity can be prevented.

[0026] Claim 3 According to the cell stack of the invention, the resin forming portion has a cylindrical resin forming port formed on the outer surface side of the end plate for supplying and draining the electrolyte. Therefore, the supply and drainage port for the electrolyte to flow through the cell stack can be formed simultaneously with the sealing of the laminate, resulting in improved production efficiency in addition to the effects described in claim 1.

[0027] Claim 4 According to the cell stack of the invention, the resin-forming portion has an annular resin-forming end formed on its peripheral edge on the outer surface side of the end plate, and in addition to the effects described in claim 1, the reliability of the sealing performance is improved.

[0028] Claim 5 According to the cell stack of the invention, the resin-forming end of the resin-forming portion has a resin-engaging portion that engages with the end plate on the outer surface side of the end plate, therefore, 4 In addition to the effects described above, the resin-formed portion is less prone to peeling, and its durability can be improved.

[0029] Claim 6According to the redox flow battery of the invention, in the cell stack comprising it, a plurality of battery cells are stacked, each cell being composed of positive and negative electrodes, a diaphragm disposed between the positive and negative electrodes, and a cell frame on which the positive and negative electrodes are arranged. A pair of end plates are placed at both ends in the stacking direction of the battery cells, and the periphery of the stacked body, that is, the outer periphery of the stacked cell frame and end plates, is integrally surrounded by a resin-molded portion, thereby sealing the entire stacked body with the resin-molded portion.

[0030] Therefore, the outer perimeter of the stacked cell frame and end plate is integrally surrounded and sealed by the resin-molded portion, eliminating the need for sealing members and conductive members for welding between the cell frame surfaces, thereby reducing the number of parts and labor. Consequently, costs can be reduced. [Brief explanation of the drawing]

[0031] [Figure 1] Figure 1 is a perspective view showing the overall configuration of a cell stack according to an embodiment of the present invention. [Figure 2] Figure 2 is a cross-sectional view illustrating the configuration of a cell stack according to an embodiment of the present invention. [Figure 3] Figure 3 is a partial diagram illustrating the configuration of a cell stack according to an embodiment of the present invention. [Figure 4] Figure 4(a) is an explanatory diagram of one side (positive electrode side) of the cell frame used to form a cell stack according to an embodiment of the present invention, and Figure 4(b) is an explanatory diagram of the other side (negative electrode side). [Figure 5] Figure 5(a) is an explanatory diagram of one side (outer surface) of one of a pair of end plates used to form a cell stack according to an embodiment of the present invention, and Figure 5(b) is an explanatory diagram of the other side (inner surface, negative electrode surface). [Figure 6] Figure 6(a) is an explanatory diagram of one side (outer surface) of the other end plate of a pair of end plates used to form a cell stack according to an embodiment of the present invention, and Figure 6(b) is an explanatory diagram of the other side (inner surface, positive electrode surface). [Figure 7] Figure 7 is a cross-sectional view illustrating the configuration of a laminate forming a cell stack according to an embodiment of the present invention. [Figure 8] Figure 8 is an explanatory diagram illustrating the assembly of a cell stack according to an embodiment of the present invention. [Figure 9] Figure 9(a) is an explanatory diagram of one side (positive electrode side) of the cell frame illustrating the state in which the liquid resin for forming the resin-forming portion of the cell stack in an embodiment of the present invention flows into the cell frame and spreads around it, and Figure 9(b) is an explanatory diagram of the other side (negative electrode side). [Figure 10] Figure 10(a) is an explanatory diagram of one side (outer surface) of the end plate illustrating the state in which the liquid resin for forming the resin-forming portion of the cell stack according to an embodiment of the present invention flows into the end plate and spreads around it, and Figure 10(b) is an explanatory diagram of the other side (inner surface) of the end plate illustrating the state in which the liquid resin for forming the resin-forming portion of the cell stack according to an embodiment of the present invention flows into the end plate and spreads around it. [Figure 11] Figure 11 is an enlarged cross-sectional view AA of Figure 10(a) illustrating the state in which a resin-formed portion is formed on the end plate of the cell stack according to an embodiment of the present invention. [Figure 12] Figure 12 is an explanatory diagram illustrating the state in which liquid resin for forming a resin-forming portion in a cell stack according to an embodiment of the present invention flows through the laminate and spreads around it. [Figure 13] Figure 13 is an explanatory diagram illustrating the resin-forming portion formed in the cell stack according to an embodiment of the present invention. [Figure 14] Figure 14(a) is an explanatory diagram of one side (positive electrode side) of a modified example 1 of the cell frame constituting the cell stack according to an embodiment of the present invention, and Figure 4(b) is an explanatory diagram of the other side (negative electrode side). [Modes for carrying out the invention]

[0032] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In this embodiment, the same symbols and reference numerals in the illustration represent the same or corresponding functional parts; therefore, their redundant explanations are omitted here.

[0033] [Embodiment] First, let's explain the general configuration of a redox flow battery. A redox flow battery consists of a tank containing an electrolyte solution in which active material ions are dissolved, a battery cell section (flow-type electrolytic cell) equipped with positive and negative electrodes 101 and a diaphragm 103 separating the positive and negative electrodes 101, which reacts the electrolyte solution to perform charging and discharging, and a pump, piping, etc., which circulate the electrolyte solution between the tank and the battery cell section. The positive electrode electrolyte solution is supplied to the positive electrode 101, and the negative electrode electrolyte solution is supplied to the negative electrode 101, and charging and discharging are performed by simultaneously promoting oxidation and reduction reactions on these positive and negative electrodes.

[0034] The battery cell section, which performs the battery reaction, is composed of a cell stack 100 in which multiple battery cells (single cells) 110 are stacked to obtain a practical voltage. The battery cell 110 is composed of a negative electrode and a positive electrode 101 with a diaphragm 103 made of an ion exchange membrane in between. Electrolyte containing an active material is supplied to each electrode 101 from a tank by a pump, causing an oxidation-reduction reaction that enables charging and discharging.

[0035] The electrolyte is not particularly limited, and any solution (including suspensions and dispersions, and regardless of whether it is in liquid or slurry form) obtained by dissolving an ionic active material that performs oxidation-reduction reactions in an electrically conductive aqueous or non-aqueous solvent can be used. For example, solutions containing metal ion active materials such as iron-chromium (Fe / Cr), vanadium (V / V), and titanium-manganese (Ti / Mn) in an aqueous solvent (e.g., an inorganic solvent such as sulfuric acid or hydrochloric acid), solutions containing non-metallic ions such as bromine, iodine, and quinone-based organic substances as active materials in an aqueous solvent (e.g., an inorganic solvent such as sulfuric acid or hydrochloric acid), solutions containing metal ion active materials such as metal complexes and polyacids in a non-aqueous solvent (e.g., an organic solvent), or solutions containing radical-based or quinone-based organic substances as active materials in an aqueous solvent (e.g., an organic solvent) can be used.

[0036] For active materials, vanadium-based (V / V) electrolytes can be used, for example, an aqueous vanadium sulfate solution. In the case of vanadium-based electrolytes, during charging, current flows into the positive electrode, oxidizing the tetravalent V ions in the positive electrode electrolyte to pentavalent, and reducing the trivalent V ions in the negative electrode electrolyte to divalent, thereby charging the device. During discharge, the reverse reaction occurs, and the electricity is extracted.

[0037] Here, the cell stack 100 according to an embodiment of the present invention will be described with reference to Figures 1 to 13. In this embodiment, the cell stack 100 applied to the redox flow battery is formed by repeatedly stacking battery cells (the smallest unit, a single cell) 110, each having positive and negative electrodes 101, a cell frame 1 with a channel for circulating electrolyte supplied to the positive and negative electrodes 101, and a diaphragm 103 interposed between the positive and negative electrodes 101. A pair of end plates 120A and 120B are arranged on both sides in the stacking direction. The stacked body 130 is placed in a predetermined mold, and liquid resin 140A is filled into the mold so that the liquid resin 140A spreads around the stacked body 130. The mold is then heated and solidified to form a resin forming portion 140 around the stacked body 130, thereby sealing the stacked body 130 integrally with the resin forming portion 140.

[0038] In a redox flow battery, each battery cell 110 constituting the cell stack 100 is separated from each other by a cell frame 1 on which electrodes 101 are arranged, and a diaphragm 103 is placed between adjacent cell frames 1. The electrodes 101, separated into positive and negative electrodes by a diaphragm 103, are inert electrodes made of carbon material. For example, porous carbon fiber aggregates such as carbon cloth, carbon felt, and carbon paper are used. Examples of carbon fibers include polyacrylonitrile (PAN) carbon fibers, pitch carbon fibers, rayon carbon fibers, and phenolic carbon fibers. However, it is also possible to use granular, spherical, tablet, or pellet-shaped carbon materials.

[0039] As will be described later, the cell frame 1 has an electrode arrangement section 105 on its inner circumference where positive and negative electrodes 101 are arranged, and a resin frame 5 is formed around the electrode arrangement section 105, and the frame 5 is provided with channels 31, 32, 41, and 42 for circulating the electrolyte supplied to the positive and negative electrodes. For example, an ion exchange membrane can be used as the diaphragm 103. The diaphragm 103 only needs to have an area greater than or equal to the area of ​​the electrode 101, but if it is to correspond to an area approximately equal to the area of ​​the cell frame 1, then holes 411, 412, 421, and 422 through which the electrolyte flows are provided, corresponding to the through holes 211, 212, 221, and 222 of the manifolds 11, 12, 21, and 22 of the cell frame 1 and the end plates 120A and 120B. In addition, through holes 451, 452, 453, and 454 through which the liquid resin 140A flows are provided, corresponding to the resin through holes 151A, 151B, 151C, and 151D of the cell frame 1 and the resin through holes 251A, 252B, 252C, and 252D of the end plates 120A and 120B. Furthermore, if the area of ​​the diaphragm 103 is to be approximately the same as the area of ​​the cell frame 1, protective material (support material) not shown may be placed around the diaphragm 103 to protect the flow path of the cell frame 1.

[0040] In this embodiment, the cell stack 100 consists of multiple battery cells (single cells) 110, each comprising a cell frame 1 on which electrodes 101 are arranged and a diaphragm 103, stacked together. Furthermore, a pair of end plates 120A and 120B are placed at both ends in the stacking direction to form a laminate 130, which is then covered and surrounded by a resin-molded portion 140.

[0041] In other words, the cell stack 100 of this embodiment is formed by stacking multiple battery cells (single cells) 110 and arranging a pair of end plates 120A and 120B at both ends in the stacking direction to form a laminate 130. This laminate 130 is then placed in a predetermined mold, and liquid resin 140A is filled into the mold so that it spreads around the laminate 130. The laminate 130 is then heated and solidified in the mold to integrally form a resin-formed portion 140 around the laminate 130 and seal it.

[0042] Here, we will describe a method for forming the resin-forming portion 140 of the cell stack 100 in this embodiment around the laminate 130. In the cell stack 100 of this embodiment, resin through-holes 151A, 151B, 151C, 152D and groove-shaped (recessed) resin channels 152A, 152B, 152C, 152D are formed in each cell frame 1 for circulating liquid resin 140A to form a resin forming section 140 around the laminate 130. In addition, resin through-holes 251A, 251B, 251C, 251D and groove-shaped (recessed) resin channels 252A, 252B, 252C, 252D are also formed in each end plate 120A, 120B for circulating liquid resin 140A. Then, within a predetermined mold, liquid resin 140A is injected and filled through resin through holes 251A, 251B, 251C, and 251D provided in the end plates 120A and 120B of the cell stack 100, and the resin through holes 151A, 151B, 151C, and 152D of each cell frame 1, as well as the resin channels 152A, 152B, 152C, and 152D, and the end plates 120A and 120B are filled. Liquid resin 140A is circulated through the resin through-holes 251A, 251B, 251C, 251D and the resin channels 252A, 252B, 252C, 252D, allowing the liquid resin 140A to spread to the outer circumference of each cell frame 1 and each end plate 120A, 120B, thereby forming a resin-forming portion 140 around the laminate 130 of the cell frames 1 and end plates 120A, 120B.

[0043] The details of the cell frame 1 of this embodiment will be explained mainly with reference to Figures 4 and 9. The cell frame 1 is formed in a substantially rectangular shape with four sides E1, E2, E3, and E4, where two opposing sides of each side are of the same length, and consists of an electrode arrangement section 105 in the center where an electrode 101 is arranged and a frame 5 provided on its outer circumference.

[0044] The electrode arrangement section 105 is not particularly limited as long as it arranges positive and negative electrodes 101 and does not mix the electrolyte between the positive and negative electrodes. For example, it can be a structure in which the positive and negative electrodes 101 are arranged via a bipolar plate, or the electrodes 101 may be integrally provided on the frame 5. The frame 5 of the cell frame 1 is made of insulating material such as vinyl chloride, polyethylene, polypropylene, fluorine, epoxy resin, or rubber, and has resistance to electrolytes (chemical resistance, acid resistance, etc.).

[0045] In this embodiment, the cell frame 1 has circular through-holes, known as manifolds 11, 12, 21, and 22, formed at the four corners of its rectangular frame 5 surrounding the electrode arrangement section 105. Specifically, it is provided with a positive electrode side electrolyte supply manifold 11 and a positive electrode side drainage manifold 21 through which the positive electrode electrolyte flows, and a negative electrode side electrolyte supply manifold 12 and a negative electrode side drainage manifold 22 through which the negative electrode electrolyte flows. As a result, when multiple cell frames 1 are stacked, the manifolds 11, 12, 21, and 22 of the frame 5 of each cell frame 1 become continuous, and these manifolds 11, 12, 21, and 22 form a flow path for the electrolyte in the stacking direction.

[0046] In this embodiment, the positive electrode side fluid supply manifold 11, the negative electrode side fluid supply manifold 12, the positive electrode side drainage manifold 21, and the negative electrode side drainage manifold 22 are all formed to the same dimensions and shape, and are symmetrically positioned relative to each other in the left-right and up-down directions with respect to the virtual vertical center line (not shown) and virtual horizontal center line (not shown) of the cell frame 1 as axes of symmetry. The positive electrode side fluid supply manifold 11 and the positive electrode side drainage manifold 21 are diagonally opposite each other on the cell frame 1, and the negative electrode side fluid supply manifold 12 and the negative electrode side drainage manifold 22 are also diagonally opposite each other on the cell frame 1.

[0047] Specifically, the positive electrode side fluid supply manifold 11 and the positive electrode side fluid drainage manifold 21 are located at two diagonal corners of the rectangular cell frame 1 (the corner formed by the intersection of two adjacent sides E1 and E4, and the corner formed by the intersection of two adjacent sides E2 and E3), and the negative electrode side fluid supply manifold 12 and the negative electrode side fluid drainage manifold 22 are located at the other diagonal corners (the corner formed by the intersection of two adjacent sides E1 and E2, and the corner formed by the intersection of two adjacent sides E3 and E4). The positive electrode side fluid supply manifold 11 and the negative electrode side fluid supply manifold 12 are located at two opposing corners on the left and right sides of the lower part of the rectangular cell frame 1, and the positive electrode side drainage manifold 21 and the negative electrode side drainage manifold 22 are located at two opposing corners on the upper part. That is, the positive electrode side fluid supply manifold 11 and the negative electrode side fluid supply manifold 12 are in a symmetrical positional relationship with respect to the vertical center line (not shown) of the cell frame 1 as the axis of symmetry, and the positive electrode side drainage manifold 21 and the negative electrode side drainage manifold 22 are also in a symmetrical positional relationship with respect to the vertical center line (not shown) of the cell frame 1 as the axis of symmetry. On one side of the rectangular cell frame 1, the positive electrode side fluid supply manifold 11 and the negative electrode side fluid drainage manifold 22 are located at two vertically opposing corners, while on the other side, the negative electrode side fluid supply manifold 12 and the positive electrode side fluid drainage manifold 21 are located at two vertically opposing corners.

[0048] Furthermore, a groove-shaped (recessed) positive electrode side inlet channel 31 is formed on the positive electrode side surface of the frame 5 of the cell frame 1, connecting the electrode arrangement section 105 and the positive electrode side liquid supply manifold 11. In addition, a groove-shaped (recessed) positive electrode side outlet channel 41 is formed between the electrode arrangement section 105 and the positive electrode side drainage manifold 21, connecting them. Similarly, a groove-shaped (recess-shaped) negative electrode side introduction channel 32 is formed on the negative electrode side surface of the frame 5, connecting the electrode arrangement section 105 and the negative electrode side liquid supply manifold 12, and a groove-shaped negative electrode side discharge channel 42 is formed, connecting the electrode arrangement section 105 and the negative electrode side drainage manifold 22.

[0049] From here, the positive electrode electrolyte, supplied by a pump from the positive electrode electrolyte tank containing the positive electrode electrolyte, flows through a tube, passing through the resin-formed ports 141A and 141B on the positive electrode electrolyte supply side, which are electrolyte input / output sections formed in a pair of end plates 120A and 120B, described later, located on both sides of the stacking direction of the cell stack 100, and through a flow path consisting of a positive electrode side electrolyte supply manifold 11 formed in the frame 5 of each cell frame 1. Furthermore, via the positive electrode side electrolyte supply manifold 11, it flows into a groove-shaped positive electrode side introduction flow path 31 that connects the positive electrode side electrolyte supply manifold 11 formed in the frame 5 of each cell frame 1 to the electrode arrangement section 105, and flows through the positive electrode side introduction flow path 31. The positive electrode electrolyte that has flowed through the positive electrode side introduction flow path 31 then flows into the positive electrode 101 of the electrode arrangement section 105 of the cell frame 1, and a battery reaction occurs on that electrode 101. Furthermore, the positive electrode electrolyte that has passed from the bottom to the top of the electrode 101 flows through a groove-shaped positive electrode side discharge channel 41 that connects the positive electrode side drainage manifold 21 formed in the frame 5 of each cell frame 1 with the electrode arrangement section 105, and is discharged from the positive electrode side drainage manifold 21. The positive electrode electrolyte discharged from the positive electrode side drainage manifold 21 flows through a channel consisting of the positive electrode side drainage manifold 21 formed in the frame 5 of each cell frame 1, and is returned to the positive electrode electrolyte tank through the resin-formed openings 141C and 141D on the negative electrode electrolyte discharge side, which are electrolyte input / output sections formed in the pair of end plates 120A and 120B described later.

[0050] Similarly, the negative electrode electrolyte supplied by a pump from the negative electrode electrolyte tank containing the negative electrode electrolyte flows through a tube, passing through resin-formed ports 141A and 141B on the negative electrode electrolyte supply side, which are electrolyte input / output sections formed on a pair of end plates 120A and 120B, described later, located on both sides of the stacking direction of the cell stack 100, and through a flow path consisting of a negative electrode side electrolyte supply manifold 12 formed in the frame 5 of each cell frame 1. Furthermore, it flows through the negative electrode side electrolyte supply manifold 12 into a groove-shaped negative electrode side introduction flow path 32 that connects the negative electrode side electrolyte supply manifold 12 formed in the frame 5 of each cell frame 1 to the electrode arrangement section 105, and flows through the negative electrode side introduction flow path 32. The negative electrode electrolyte that has flowed through the negative electrode side introduction flow path 32 then flows into the negative electrode 101 of the electrode arrangement section 105 of the cell frame 1, and a battery reaction occurs on that electrode 101. Furthermore, the negative electrode electrolyte that has passed from the bottom to the top of the electrode 101 flows through a groove-shaped negative electrode side discharge channel 42 that connects the negative electrode side drainage manifold 22 formed in the frame 5 of each cell frame 1 with the electrode arrangement section 105, and is discharged from the negative electrode side drainage manifold 22. The negative electrode electrolyte discharged from the negative electrode side drainage manifold 22 flows through a channel consisting of the negative electrode side drainage manifold 22 formed in the frame 5 of each cell frame 1, and is returned to the negative electrode electrolyte tank through the resin-formed ports 141C and 141D on the negative electrode discharge side, which are electrolyte input / output sections formed in the pair of end plates 120A and 120B described later.

[0051] Note that the positive electrode side electrolyte supply manifold 11 and the negative electrode side electrolyte supply manifold 12 differ only in the flow path of the positive electrode electrolyte or the negative electrode electrolyte, and their basic structure is the same. Therefore, unless otherwise specified, they will simply be referred to as electrolyte supply manifolds 11 and 12. The same applies to the positive electrode side drainage manifold 21 and the negative electrode side drainage manifold 22. Therefore, unless otherwise specified, they will simply be referred to as drainage manifolds 21 and 22. Furthermore, the positive electrode side inlet channel 31 and the negative electrode side inlet channel 32 are essentially the same in structure, differing only in whether they are for the positive or negative electrode electrolyte. Therefore, unless otherwise specified, they will simply be referred to as inlet channels 31 and 32. The same applies to the positive electrode side discharge channel 41 and the negative electrode side discharge channel 42. Therefore, unless otherwise specified, they will simply be referred to as discharge channels 41 and 42.

[0052] In the cell frame 1 shown in Figure 4, the introduction channels 31 and 32 connecting the electrode arrangement section 105 and the liquid supply manifolds 11 and 12 are formed to gradually widen from the liquid supply manifolds 11 and 12 side toward the lateral direction (width direction) of the electrode arrangement section 105, that is, toward a pair of inner circumferential edges facing each other in the left-right direction on the inner circumference of the frame 5 surrounding the electrode arrangement section 105. The electrolyte supplied from the liquid supply manifolds 11 and 12 is guided toward the lateral direction (width direction) of the cell frame 1 and toward the upper side where the discharge channels 41 and 42 facing the introduction channels 31 and 32 are formed, and supplied to the electrodes 101 of the electrode arrangement section 105. In addition, a backflow prevention section 60 is provided along the way to prevent backflow of the electrolyte. Furthermore, the discharge channels 41 and 42 connecting the electrode arrangement section 105 and the drainage manifolds 21 and 22 are formed to gradually narrow from the electrode arrangement section 105 towards the drainage manifolds 21 and 22, guiding the electrolyte that has passed through the electrode 101 to the upper side of the cell frame 1 and along the longitudinal direction of the cell frame 1, and discharging it from the drainage manifolds 21 and 22. In addition, a backflow prevention section 70 is provided along the way to prevent backflow of the electrolyte.

[0053] As shown in Figure 4, the cell frame 1 contains flow channels 31, 32, 41, and 42 that circulate the electrolyte between the manifolds 11, 12, 21, and 22 and the electrode arrangement section 105. These channels are widened from the manifold 11, 12, 21, and 22 side to match the width of the inner circumference of the frame 5 surrounding the electrode arrangement section 105. As a result, the width of the flow channels 31, 32, 41, and 42 is larger in diameter than the manifolds 11, 12, 21, and 22, and the flow channel length is also shorter. This reduces the fluid resistance of the electrolyte flowing through them, thereby reducing the pressure loss of the electrolyte supplied to the cell frame 1. Furthermore, by providing backflow prevention sections 60 and 70 in the middle of the flow channels 31, 32, 41, and 42 to prevent backflow of the electrolyte, current loss (shunt current loss) through the electrolyte can be reduced. Therefore, according to the cell frame 1 shown in Figure 4, the electrolyte can be supplied to the electrodes with low pressure loss, and shunt current loss can also be reduced. Thus, it is possible to increase the output power of the redox flow battery. However, when implementing the present invention, the configuration of the electrolyte flow path is not limited to the above.

[0054] Furthermore, in the cell frame 1 of this embodiment, as shown in Figure 4, multiple ribs 115 are formed at the connection ends with manifolds 11, 12, 21, and 22 on the flow paths 31, 32, 41, and 42. This reinforces the area around the manifolds 11, 12, 21, and 22, preventing deformation of the cell frame 1 due to the internal pressure of the electrolyte and liquid resin 140A flowing through the manifolds 11, 12, 21, and 22. In addition, the multiple ribs 115 hold down the diaphragm 103, which is positioned between adjacent cell frames 1 in the cell stack 100, preventing displacement of the diaphragm 103. In particular, in this embodiment, ribs 115 are provided at two diagonally opposite locations on each of the front and back surfaces of the cell frame 1, and the ribs 115 at two locations on each of the cell frames 1 that are facing each other with the diaphragm 103 in between hold down the diaphragm 103 at its four corners (four locations), thereby preventing displacement of the diaphragm 103. Furthermore, the internal pressure of the electrolyte and liquid resin 140A prevents the diaphragm 103 from falling into the recesses of the flow channels 31, 32, 41, and 42, thereby preventing damage to the diaphragm 103 and extending its lifespan.

[0055] The ribs 115 shown in Figure 4, etc., are formed by dividing the flow paths 31, 32, 41, and 42 into multiple sections and creating protrusions, which protrude from the bottom of the grooves formed at a lower position than the surrounding surfaces of the manifolds 11 and 12. As a result, multiple parallel branch grooves are formed in the flow paths 31, 32, 41, and 42 by the division by the protruding ribs 115. In Figure 4, etc., three protruding ribs 115 are formed in 31, 32, 41, and 42 at approximately the same height as the flow path forming walls that form the flow paths 31, 32, 41, and 42, resulting in the formation of four parallel branch grooves with a depth of less than half the height of the surrounding walls that form the manifolds 11, 12, 21, and 22. Therefore, the electrolyte introduced from the supply manifolds 11 and 12 branches into four and flows through the branch grooves. However, when implementing the present invention, it is not limited to three ribs 115, but may be one, two, or four or more.

[0056] In this embodiment, the cell frame 1 used to form the cell stack 100 having the resin forming portion 140 has a frame 5 that is provided with small-diameter circular resin through holes 151A, 151B, 151C, 151D and groove-shaped (recessed) resin channels 152A, 152B, 152C, 152D around its outer circumference for circulating the liquid resin 140A for forming the resin forming portion 140.

[0057] The resin through-holes 151A, 151B, 151C, and 151D for circulating the liquid resin 140A are formed by penetrating the front and back surfaces (thickness direction) of the frame 5 of the cell frame 1. They have a smaller diameter than the supply manifolds 11, 12 and drainage manifolds 21, 22 through which the electrolyte flows during battery charging and discharging, and are located near the supply manifolds 11, 12 and drainage manifolds 21, 22 (near the side opposite the corners of the cell frame 1). In the cell frame 1 shown in Figure 4, a resin through-hole 151A is formed between the positive electrode side fluid supply manifold 11 and the inlet channels 31 and 32, and a resin through-hole 151C is formed between the positive electrode side fluid drainage manifold 21 and the outlet channels 41 and 42. Furthermore, a resin through-hole 151B is formed between the negative electrode side fluid supply manifold 12 and the inlet channels 31 and 32, and a resin through-hole 151D is formed between the negative electrode side fluid drainage manifold 22 and the outlet channels 41 and 42.

[0058] Furthermore, on the positive electrode side of the frame 5 of the cell frame 1 through which the positive electrode electrolyte flows during charging and discharging of the battery, groove-shaped (recessed) resin channels 152B and 152D are formed between the negative electrode side electrolyte supply manifold 12 and negative electrode side electrolyte drainage manifold 22, which are provided at two diagonal corners of the cell frame 1, and the introduction channel 31 and discharge channel 41.

[0059] Specifically, as shown in Figure 4(a), the resin channel 152B formed between the negative electrode side liquid supply manifold 12 and the positive electrode side introduction channel 31, which are located at the corner formed by the intersection of two adjacent sides E1 and E2 on the outer edge of the cell frame 1, is formed to connect the negative electrode side liquid supply manifold 12 with the vertical side E2 of the cell frame 1, and to intersect the vertical side E2 of the cell frame 1 at approximately a right angle. The resin channel 152D, which is formed between the negative electrode side drainage manifold 22 and the positive electrode side discharge channel 41, is located at the corner formed by the intersection of two adjacent sides E3 and E4 on the outer edge of the cell frame 1. The resin channel 152D is formed to connect the resin through-hole 151D with the vertical side E4 of the cell frame 1, and to intersect the vertical side E4 of the cell frame 1 at approximately a right angle.

[0060] Similarly, on the negative electrode side of the frame 5 of the cell frame 1 through which the negative electrode electrolyte flows during charging and discharging of the battery, groove-shaped (recessed) resin channels 152A and 152C are formed between the positive electrode side electrolyte supply manifold 11 and the negative electrode side electrolyte supply manifold 21, which are provided at two diagonal corners of the cell frame 1, and the introduction channel 32 and the discharge channel 42.

[0061] Specifically, as shown in Figure 4(b), the resin channel 152A, which is formed between the positive electrode side fluid supply manifold 11 and the negative electrode side introduction channel 32, is located at the corner formed by the intersection of two adjacent sides E1 and E4 on the outer edge of the cell frame 1. The resin channel is formed to connect the resin through-hole 151A with the vertical side E4 of the cell frame 1, and to intersect each side of the vertical side E4 of the cell frame 1 at approximately right angles. The resin channel 152C, formed between the positive electrode side drainage manifold 21 and the negative electrode side discharge channel 42, which are located at the corner formed by the intersection of two adjacent sides E2 and E3 on the outer edge of the cell frame 1, is formed to connect the resin through hole 151C with the vertical side E2 of the cell frame 1, and to intersect the vertical side E2 of the cell frame 1 at approximately a right angle.

[0062] As a result, when multiple cell frames 1 are stacked, the resin through-holes 151A, 151B, 151C, and 151D formed in the frame 5 of each cell frame 1 become continuous, and these resin through-holes 151A, 151B, 151C, and 151D form a flow path for the liquid resin 140A in the stacking direction of the cell frames 1. Furthermore, the frame 5 of each cell frame 1 has groove-shaped resin channels 152A, 152B, 152C, and 152D that connect the resin through holes 151A, 151B, 151C, and 151D with the outer edge of the cell frame 1. As a result, the liquid resin 140A flowing through the resin through holes 151A, 151B, 151C, and 151D flows through the resin channels 152A, 152B, 152C, and 152D formed in the frame 5 of each cell frame 1, and spreads around the outer circumference of each cell frame 1, covering the entire circumference of the four sides E1, E2, E3, and E4 of the outer edge end face of the cell frame 1.

[0063] Specifically, as shown in Figures 9 and 12, the liquid resin 140A flowing through the resin through-holes 151A formed in each cell frame 1 flows to the side E4 of the outer edge of the cell frame 1 via groove-shaped resin channels 152A formed on the surface of the cell frame 1, the liquid resin 140A flowing through the resin through-holes 151B flows to the side E2 via groove-shaped resin channels 152B formed on the surface of the cell frame 1, the liquid resin 140A flowing through the resin through-holes 151C flows to the side E2 via groove-shaped resin channels 152C formed on the surface of the cell frame 1, and the liquid resin 140A flowing through the resin through-holes 151D flows to the side E4 via groove-shaped resin channels 152D formed on the surface of the cell frame 1. Then, the liquid resin 140A that flows from the resin through-hole 151A through the resin channel 152A to the side E4, and the liquid resin 140A that flows from the resin through-hole 151B through the resin channel 152B to the side E2, also flows to the side E1 adjacent to side E4 of the cell frame 1, and merges on side E1 of the cell frame 1. The liquid resin 140A that flows from the resin through-hole 151C through the resin channel 152C to the side E2, and the liquid resin 140A that flows from the resin through-hole 151D through the resin channel 152D to the side E4, also flows to the side E3 adjacent to side E4 of the cell frame 1, and merges on side E3 of the cell frame 1. As a result, the liquid resin 140A spreads throughout the entire perimeter of the four sides E1, E2, E3, and E4 of the outer edge end face of each cell frame 1, and as it cools and solidifies, a resin forming portion 140 is formed on the outer perimeter of each cell frame 1.

[0064] Furthermore, in this embodiment, resin grooves 155A, 155B, 155C, and 155D are provided at the outer edge of the cell frame 1, into which the liquid resin 140A that has reached the outer circumference of the frame 5 of the cell frame 1 enters. The resin grooves 155A, 155B, 155C, and 155D in this embodiment are not in communication with the resin through holes 151A, 151B, 151C, and 151D by the resin channels 152A, 152B, 152C, and 152D. In other words, they are formed at the outer edge ends of the sides E3 and E1 of the cell frame 1 where the resin channels 152A, 152B, 152C, and 152D are not formed. The resin engagement portion 140e is formed when the liquid resin 140A that has reached the outer circumference of the frame 5 of the cell frame 1 flows into these resin grooves 155A, 155B, 155C, and 155D.

[0065] Next, the details of the end plates 120A and 120B, which are arranged at both ends of the cell frame 1 in the stacking direction, will be explained mainly with reference to Figures 5, 6, and 9. In this embodiment, the end plates 120A and 120B, which are used to form the cell stack 100 having the resin-molded portion 140 and are arranged on both sides of the cell frame 1 in the stacking direction, are made by inserting a current collector 128 into a frame 125. The current collector 128 and the frame 125 are integrally formed insert molded products by setting the current collector 128 in an injection molding die and filling the area around it with resin to form the frame 125. Such insert molded products can be obtained with high precision and stable quality. In this embodiment, the end plates 120A and 120B have approximately the same length and width dimensions as the cell frame 1, but their thickness is about 3 to 5 times greater than that of the cell frame 1.

[0066] The frame 125 of the end plates 120A and 120B is made of an insulating material such as vinyl chloride, polyethylene, polypropylene, fluorine, epoxy resin, or rubber, and has resistance to electrolytes (chemical resistance, acid resistance, etc.). Usually, the same resin as the frame 5 of the cell frame 1 is used, but different materials may be used.

[0067] The current collector 128, inserted within the frame 125, is electrically connected to the electrode 101 of the electrode arrangement section 105 in the cell frame 1 and is a conductive member for performing electrical input and output between the electrode 101 in the cell stack 100 and external equipment. For example, carbon such as graphite, resin, metals such as nickel, iron, stainless steel, titanium, copper, and aluminum, or metal plating such as gold-plated copper sheet can be used. In this embodiment, the current collector 128 is connected to a metal energizing terminal 182, such as a copper rod, which is connected to an external device such as an inverter via lead wires, and electrically connects the cell stack 100 to the external power supply.

[0068] In this embodiment, multiple screw holes (recesses) 128A are formed on the outer side of the front and back surfaces in the thickness direction of the current collector 128, into which the current-carrying terminals 182 are inserted, and the current-carrying terminals 182, which have threads cut into them, are screwed into these screw holes 128A. In detail, in the frame 125 into which the current collector 128 is inserted, a round opening 125A is formed at a position corresponding to the screw hole 128A of the current collector 128, and the opening 125A in the frame 125 is used to screw the current terminal 182 into the screw hole (recess) 128A of the current collector 128. The current terminal 182, screwed into the screw hole (recess) 128A of the current collector 128, is then fixed to the current collector 128 by screwing in a nut 184. In the figure, the nut 184 is smaller in diameter than the opening 125A in the frame 125 and is screwed onto the current terminal 182 within the opening 125A.

[0069] In particular, in the end plates 120A and 120B shown in Figure 5, the current collector 128 has screw holes (recesses) 128A in a total of 8 locations: 3 in the upper row, 2 in the middle row, and 3 in the lower row; and 3 in the left column, 2 in the center column, and 3 in the right column. The frame 125 also has openings 125A corresponding to these screw holes (recesses) 128A in a total of 8 locations: 3 in the upper row, 2 in the middle row, and 3 in the lower row; and 3 in the left column, 2 in the center column, and 3 in the right column. This allows the connection point of the current terminal 182 to be selected at any position and location depending on the number of stacked cell frames 1 of the cell stack 100. Furthermore, weight reduction can be achieved by forming multiple openings 125A and screw holes 128A. In Figure 5, etc., the power supply terminals 128 are connected to the current collector 128 at a total of four locations: two locations in the center column of the upper and lower rows, and two locations in the middle row of the left and right columns.

[0070] In this embodiment, a pair of end plates 120A and 120B used to form the cell stack 100 having the resin-molded portion 140 are also provided with large-diameter circular through holes 211, 212, 221, and 222 that correspond to the manifolds 11, 12, 21, and 22 of the cell frame 1. Specifically, through-holes 211 and 212 for supplying electrolyte to the positive electrode side, through which positive and negative electrolytes flow in from the positive and negative electrolyte tanks by pump, and through-holes 221 and 222 for draining electrolyte to the positive electrode side, through which positive and negative electrolytes are discharged toward the positive and negative electrolyte tanks, are formed in the four rectangular corners of the end plates 120A and 120B when viewed from the front, penetrating both the front and back, that is, penetrating the thickness of the current collector 128 and the frame 125. In addition, in the end plates 120A and 120B arranged at both ends in the stacking direction of the cell frame 1, the positive electrode side fluid supply through hole 211 corresponds to the positive electrode side fluid supply manifold 11 of the cell frame 1, the negative electrode side fluid supply through hole 212 corresponds to the negative electrode side fluid supply manifold 12 of the cell frame 1, the positive electrode side drainage through hole 221 corresponds to the positive electrode side drainage manifold 21 of the cell frame 1, and the negative electrode side fluid supply through hole 222 corresponds to the negative electrode side drainage manifold 22 of the cell frame 1.

[0071] From here, the positive and negative electrolytes that enter through the resin-formed ports 141A and 141B on the electrolyte supply side, which are the electrolyte input / output section described later, flow through the positive electrode side electrolyte supply through-holes 211 and negative electrode side electrolyte supply through-holes 212 of each end plate 120A and 120B to the positive electrode side electrolyte supply manifold 11 and negative electrode side electrolyte supply manifold of each cell frame 1. Furthermore, the positive and negative electrolytes that have flowed through the positive electrode side discharge through-holes 21 and 22 of each cell frame 1 flow out through the positive electrode side discharge through-holes 221 and 222 of each end plate 120A and 120B to the resin-formed ports 141C and 141D on the electrolyte discharge side, which are the electrolyte input / output section described later.

[0072] Furthermore, in the pair of end plates 120A and 120B, circular resin through-holes 251A, 251B, 251C, and 251D are provided in the vicinity of the four corners of the rectangular perimeter in a front view (on the opposite side of the corners of the end plates 120A and 120B), corresponding to the small-diameter resin through-holes 151A, 151B, 151C, and 151D of the cell frame 1. These circular resin through-holes are smaller in diameter than the through-holes 211, 212, 221, and 222 in a front view.

[0073] Specifically, a resin through-hole 251A is formed near the positive electrode side fluid supply through-hole 211, penetrating the thickness of the current collector 128 and the frame 125; a resin through-hole 251B is formed near the negative electrode side fluid supply through-hole 212, penetrating the thickness of the current collector 128 and the frame 125; a resin through-hole 251C is formed near the positive electrode side drainage through-hole 221, penetrating the thickness of the current collector 128 and the frame 125; and a resin through-hole 251D is formed near the negative electrode side drainage through-hole 222, penetrating the thickness of the current collector 128 and the frame 125.

[0074] Furthermore, the resin through-holes 251A, 251B, 251C, and 251D provided in the end plates 120A and 120B are for the flow of liquid resin 140A for forming the resin forming section 140. The resin through-hole 251A corresponds to the resin through-hole 151A of the cell frame 1, the resin through-hole 251B corresponds to the resin through-hole 151B of the cell frame 1, the resin through-hole 251C corresponds to the resin through-hole 151C of the cell frame 1, and the resin through-hole 251D corresponds to the resin through-hole 151D of the cell frame 1.

[0075] Here, in the pair of end plates 120A and 120B positioned at both ends in the stacking direction of the cell frame 1, flow channels 231, 232, 241, and 242 for the flow of electrolyte are formed on the side facing the cell frame 1, similar to the cell frame 1.

[0076] In one of the pair of end plates 120A and 120B, end plate 120A has a roughly rectangular opening 125B in the center of the frame 125 on the side facing the adjacent cell frame 1, as shown in Figure 6. A groove-shaped (recessed) negative electrode side introduction channel 232 is formed in the frame 125, connecting the opening 125B and the negative electrode side liquid supply through hole 212. Additionally, a groove-shaped (recessed) negative electrode side discharge channel 242 is formed in the frame 125, connecting the opening 125B and the negative electrode side drainage through hole 222. Similarly, in the other end plate 120B, as shown in Figure 5, a roughly rectangular opening 125B is formed in the center of the frame 125 on the side facing the adjacent cell frame 1, and a groove-shaped (recessed) positive electrode side introduction channel 231 is formed in the frame 125 that connects the opening 125B and the positive electrode side liquid supply through hole 211, and a groove-shaped (recessed) positive electrode side discharge channel 241 is also formed in the frame 125 that connects the opening 125B and the positive electrode side drainage through hole 221.

[0077] Specifically, as shown in Figure 6, the end plate 120A faces the positive electrode side of the cell frame 1, i.e., the side where the positive electrode side introduction channel 31 and positive electrode side discharge channel 41 through which the positive electrode electrolyte flows are formed, via a diaphragm 130 between it and the adjacent cell frame 1. The negative electrode side introduction channel 232 and negative electrode side discharge channel 242 through which the negative electrode electrolyte flows are formed on the side facing the cell frame 1. An opening 125B is formed between the negative electrode side inlet channel 232 and the negative electrode side discharge channel 242, and the current collector 128 inserted into the frame 125 is exposed. Subsequently, in the end plate 120A, the negative electrode electrolyte that has flowed through the negative electrode side fluid supply through hole 212 flows into the negative electrode side introduction channel 232 on the side facing the cell frame 1, flows through it, and is supplied to the current collector 128 that is exposed from the opening 125B. Furthermore, the negative electrode electrolyte that has passed through the current collector 128 from bottom to top flows through the negative electrode side discharge channel 242 and is discharged from the negative electrode side drainage through hole 222.

[0078] Furthermore, as shown in Figure 5, the end plate 120B faces the negative electrode side of the cell frame 1, i.e., the side where the negative electrode side introduction channel 32 and negative electrode side discharge channel 42 through which the negative electrode electrolyte flows, via a diaphragm 130 between it and the adjacent cell frame 1. A positive electrode side introduction channel 231 and a positive electrode side discharge channel 241 through which the positive electrode electrolyte flows are formed on the side facing the cell frame 1. An opening 125B is formed between the positive electrode side inlet channel 231 and the positive electrode side outlet channel 241, and the current collector 128 inserted into the frame 125 is exposed. From this point onward, in the end plate 120B, the positive electrode electrolyte that has flowed through the positive electrode side fluid supply through hole 211 flows into the positive electrode side introduction channel 231 on the side facing the cell frame 1, flows through it, and is supplied to the current collector 128 that is exposed from the opening 125B. Furthermore, the positive electrode electrolyte that has passed through the current collector 128 from bottom to top flows through the positive electrode side discharge channel 241 and is discharged from the positive electrode side drainage through hole 221.

[0079] In Figures 5 and 6, as with cell frame 1, the introduction channels 231 and 232 are formed to gradually widen from the liquid supply through holes 211 and 212 towards the lateral direction (width direction) of the opening 125B, that is, towards a pair of inner circumferential edges facing each other in the left-right direction on the inner circumference of the frame 125. The electrolyte supplied from the liquid supply through holes 211 and 212 is guided towards the upper side where the discharge channels 41 and 42, opposite to the introduction channels 31 and 32, are formed, and supplied to the current collector 128 exposed from the opening 125B. A backflow prevention section 60 is also provided along the way to prevent backflow of the electrolyte. Furthermore, the discharge channels 241 and 242 are formed to gradually narrow from the opening 125B side toward the drainage through holes 221 and 222, guiding the electrolyte that has passed through the current collector 128 to the upper side of the cell frame 1 and along the longitudinal direction of the cell frame 1, and discharging it from the drainage through holes 221 and 222. In addition, a backflow prevention section 70 is provided along the way to prevent backflow of the electrolyte.

[0080] Therefore, according to the end plates 120A and 120B shown in Figures 5 and 6, the flow paths 231, 232, 241, and 242 that circulate the electrolyte between the through holes 211, 212, 221, and 222 and the opening 105B are widened to match the width of the inner circumference of the frame 125 from which the current collector 128 emerges from the through holes 211, 212, 221, and 222. As a result, the width of the flow paths 231, 232, 241, and 242 is larger in diameter than the through holes 211, 212, 221, and 222, and the length of the flow paths is also shorter. This reduces the fluid resistance of the electrolyte circulating through them, and makes it possible to reduce the pressure loss of the electrolyte supplied to the end plates 120A and 120B. Furthermore, by providing backflow prevention sections 60 and 70 in the middle of the flow paths 231, 232, 241, and 242 to prevent backflow of the electrolyte, the current loss (shunt current loss) through the electrolyte can be reduced.

[0081] Furthermore, in the end plates 120A and 120B of this embodiment, as shown in Figure 10, similar to the cell frame 1, multiple ribs 115 are formed at the connection ends of the flow channels 231, 232, 241, and 242 with the through holes 211, 212, 221, and 222. This reinforces the area around the through holes 211, 212, 221, and 222 in the frame 125, preventing deformation of the frame 125 due to the internal pressure of the electrolyte and liquid resin 140A flowing through the through holes 211, 212, 221, and 222. In addition, the multiple ribs 115 hold down the diaphragm 103, which is positioned between adjacent cell frames 1 in the cell stack 100, preventing displacement of the diaphragm 103. In particular, in this embodiment, ribs 115 are provided at two diagonally opposite locations on each of the front and back surfaces of the cell frame 1, and ribs 115 are also provided at two diagonally opposite locations on the inner surfaces of the end plates 120A and 120B. The ribs 115 at two locations each of the cell frame 1 and the end plates 120A and 120B, which are opposite each other and sandwich the diaphragm 103, press down on the four corners (four locations) of the diaphragm 103, thereby preventing the diaphragm 103 from shifting position. Furthermore, the internal pressure of the electrolyte and liquid resin 140A prevents the diaphragm 103 from falling into the recesses of the flow channels 231, 232, 241, and 24, preventing damage to the diaphragm 103 due to falling and extending the lifespan of the diaphragm 103.

[0082] Furthermore, in the ribs 115 shown in Figures 5(b) and 6(b), the flow channels 231, 232, 241, and 242 are divided into multiple sections and formed as protrusions, which protrude from the bottom of the grooves formed at a lower position than the surrounding surface of the through holes 211, 212, 221, and 222. As a result, multiple parallel branch grooves are formed in the flow channels 231, 232, 241, and 242 by the division by the protruding ribs 115. Also, in Figures 5(b) and 6(b), three protruding ribs 115 are formed in the flow channels 231, 232, 241, and 242 at approximately the same height as the flow channel forming wall, resulting in the formation of four parallel branch grooves with a depth of less than half the height of the surrounding wall forming the through holes 211, 212, 221, and 222. Therefore, the electrolyte introduced through the through holes 211, 212, 221, and 222 branches out into four directions and flows into the branch grooves. However, when implementing the present invention, it is not limited to three ribs 115, but may be one, two, or four or more.

[0083] Thus, in the end plates 120A and 120B, an electrolyte is supplied to the current collector 128 inserted into the frame 125, thereby causing a battery reaction. In other words, in the cell stack 100 of this embodiment, a pair of end plates 120A and 120B are arranged at both ends of the stacked cell frame 1 in the stacking direction via a diaphragm 103.

[0084] In the end plates 120A and 120B of this embodiment, an opening 125B is formed in the center of the frame 125 on the side facing the cell frame 1, exposing the current collector 128. Electrolyte flow paths 231, 232, 241, and 242 are provided, connecting the opening 125B to the through holes 211, 212, 221, and 222. Thus, in the end plates 120A and 120B of this embodiment, electrolyte flows from the through holes 211 and 212 to the electrolyte flow paths 231 and 232 on the inner surface side facing the cell frame 1. This electrolyte is supplied to the current collector 128 exposed by the opening 125B of the frame 125, causing a battery reaction to occur. The electrolyte that has passed through the current collector 128 is discharged through the electrolyte flow paths 241 and 242 to the through holes 221 and 222.

[0085] In particular, the end plates 120A and 120B shown in Figures 5 and 6 allow the electrolyte to be supplied to the current collector 128 with low pressure loss, and also reduce shunt current loss. In addition, when implementing the present invention, it is not necessary to circulate the electrolyte in the end plates 120A and 120B, and the configuration of the electrolyte flow path is not limited to the above. However, if the electrolyte is supplied to the current collector 128 in the end plates 120A and 120B, and a battery reaction is generated there, the output can be improved in a space-saving manner.

[0086] Furthermore, in the end plate 120A used to form the cell stack 100 having the resin-molded portion 140, on the side facing the cell frame 1 and where the flow channels 232 and 242 through which the negative electrode electrolyte flows during charging and discharging of the battery are formed, as shown in Figure 6, groove-shaped (recessed) resin flow channels 252A and 252C are formed between the supply through-holes 212 and drain through-holes 222 provided at two diagonal corners and the introduction flow channel 232 and discharge flow channel 242.

[0087] Specifically, as shown in Figure 6(b), the resin channel 252A, formed between the liquid supply through-hole 211, which is located at the corner formed by the intersection of two adjacent edges E11 and E14 on the outer edge of the end plate 120A, and the negative electrode side introduction channel 132, is formed to connect the liquid supply through-hole 211 with the vertical edge E14 of the cell frame 1, and to intersect approximately perpendicularly with the vertical edge E14 of the cell frame 1. The resin channel 252C, formed between the drainage through-hole 221, which is located at the corner formed by the intersection of two adjacent edges E12 and E13 on the outer edge of the end plate 120A, and the negative electrode side discharge channel 242, is formed to connect the resin through-hole 251C with the vertical edge E12 of the cell frame 1, and to intersect approximately perpendicularly with the vertical edge E12 of the cell frame 1.

[0088] Furthermore, on the outer surface of the end plate 120A, opposite to the surface facing the cell frame 1, groove-shaped (recessed) resin channels 252B and 252D are formed between the diagonally opposite corners of the liquid supply through-holes 212 and the liquid drainage through-holes 222 and the recess 126.

[0089] Specifically, as shown in Figure 6(a), the resin channel 252B formed between the liquid supply through-hole 212 and the recess 126, which are located at the corner formed by the intersection of two adjacent edges E11 and E12 on the outer edge of the end plate 120A, is formed to connect the liquid supply through-hole 212 with the vertical edge E12 of the cell frame 1, and to intersect approximately at a right angle with the vertical edge E12 of the cell frame 1. The resin channel 252D formed between the drainage through-hole 222 and the recess 126, which are located at the corner formed by the intersection of two adjacent edges E13 and E14 on the outer edge of the end plate 120A, is formed to connect the drainage through-hole 222 with the vertical edge E14 of the cell frame 1, and to intersect approximately at a right angle with the vertical edge E14 of the cell frame 1.

[0090] Similarly, in the end plate 120B used to form the cell stack 100 having the resin-molded portion 140, on the side facing the cell frame 1 and where the flow channels 231 and 241 through which the positive electrode electrolyte flows during charging and discharging of the battery are formed, as shown in Figure 5, groove-shaped (recessed) resin flow channels 252B and 252D are formed between the supply through-holes 212 and drain through-holes 222 provided at two diagonal corners and the introduction flow channel 231 and discharge flow channel 241.

[0091] Specifically, as shown in Figure 5(b), the resin channel 252B formed between the liquid supply through-hole 212, which is located at the corner formed by the intersection of two adjacent edges E11 and E12 on the outer edge of the end plate 120B, and the negative electrode side introduction channel 231, is formed to connect the liquid supply through-hole 212 with the vertical edge E12 of the cell frame 1, and to intersect the vertical edge E12 of the cell frame 1 at approximately a right angle. The resin channel 252D formed between the drainage through-hole 222, which is located at the corner formed by the intersection of two adjacent edges E13 and E14 on the outer edge of the end plate 120B, and the negative electrode side discharge channel 241, is formed to connect the drainage through-hole 222 with the vertical edge E12 of the cell frame 1, and to intersect the vertical edge E12 of the cell frame 1 at approximately a right angle.

[0092] Furthermore, on the outer surface of the end plate 120B, opposite to the surface facing the cell frame 1, groove-shaped (recessed) resin channels 252A and 252C are formed between the diagonally opposite corners of the liquid supply through-holes 211 and the liquid drainage through-holes 221 and the recess 126.

[0093] Specifically, as shown in Figure 5(a), the resin channel 252A, formed between the liquid supply through-hole 211 and the recess 126 at the corner formed by the intersection of two adjacent edges E11 and E12 on the outer edge of the end plate 120B, is formed to connect the liquid supply through-hole 211 with the vertical edge E14 of the cell frame 1, and to intersect approximately at a right angle with the vertical edge E14 of the cell frame 1. The resin channel 252C, formed between the drainage through-hole 221 and the recess 126 at the corner formed by the intersection of two adjacent edges E13 and E14 on the outer edge of the end plate 120B, is formed to connect the drainage through-hole 221 with the vertical edge E12 of the cell frame 1, and to intersect approximately at a right angle with the vertical edge E12 of the cell frame 1.

[0094] Furthermore, each end plate 120A, 120B has a current collector 128 inserted into it and is larger than the thickness of the cell frame 1, making it less prone to deformation. For this reason, the resin through holes 251A, 251B, 251C, 251D in each end plate 120A, 120B are made larger in diameter than the resin through holes 151A, 151B, 151C, 151D in the cell frame 1, to facilitate the passage of resin. On the other hand, the width of the groove-shaped resin channels 252A, 252B, 252C, 252D that connect the resin through holes 251A, 251B, 251C, 251D to the outer edge of the end plates 120A, 120B1 is approximately the same as that of the resin channels 152A, 152B, 152C, 152D in the cell frame 1.

[0095] Thus, each end plate 120A, 120B has groove-shaped resin channels 252A, 252B, 252C, and 252D that connect the resin through holes 251A, 251B, 251C, and 251D with the outer edge of each end plate 120A, 120B1. As a result, the liquid resin 140A flowing through the resin through holes 251A, 251B, 251C, and 251D flows through the resin channels 252A, 252B, 252C, and 252D formed in the frame 125 of each end plate 120A, 120B, around the outer circumference of each end plate 120A, 120B, and spreads around the entire circumference of the four edges E11, E12, E13, and E14 of the outer edge end face of each end plate 120A, 120B.

[0096] Specifically, the liquid resin 140A flowing through the resin through-holes 251A formed in each end plate 120A, 120B flows towards the outer edge E14 side of the end plates 120A, 120B via groove-shaped resin channels 252A formed on the surfaces of the end plates 120A, 120B; the liquid resin 140A flowing through the resin through-holes 251B flows towards the edge E12 side via groove-shaped resin channels 252B formed on the surfaces of the end plates 120A, 120B; the liquid resin 140A flowing through the resin through-holes 251C flows towards the edge E12 side via groove-shaped resin channels 252C formed on the surfaces of the end plates 120A, 120B; and the liquid resin 140A flowing through the resin through-holes 251D flows towards the edge E14 side via groove-shaped resin channels 252D formed on the surfaces of the end plates 120A, 120B.

[0097] Then, the liquid resin 140A that flows from the resin through-hole 251A through the resin channel 252A towards the edge E14 side, and the liquid resin 140A that flows from the resin through-hole 251B through the resin channel 252B towards the edge E12 side, also flows into the edge E11 side adjacent to the edge E14 of the end plates 120A and 120B, and merges on the edge E11 of the end plates 120A and 120B. The liquid resin 140A that flows from the resin through-hole 251C through the resin channel 252C towards the edge E12 side, and the liquid resin 140A that flows from the resin through-hole 251D through the resin channel 252D towards the edge E14 side, also flows into the edge E13 side adjacent to the edge E14 of the end plates 120A and 120B, and merges on the edge E13 of the end plates 120A and 120B. As a result, the liquid resin 140A spreads throughout the entire perimeter of the four edges E11, E12, E13, and E14 of the outer edge surface of each end plate 120A, 120B, and as it cools and solidifies, a resin-formed portion 140 is also formed around the outer perimeter of each end plate 120A, 120.

[0098] Furthermore, in this embodiment, resin grooves 255A, 255B, 255C, and 255D are provided on the outer edges of the end plates 120A and 120B, into which the liquid resin 140A that has reached the outer circumference of the end plates 120A and 120B enters. In this embodiment, the resin grooves 255A, 255B, 255C, and 255D are not in communication with the resin through holes 251A, 251B, 251C, and 251D by the resin channels 252A, 252B, 252C, and 252D, that is, they are formed at the outer edges of the end plates 120A and 120B on the edge E13 and edge E11 sides where the resin channels 252A, 252B, 252C, and 252D are not formed. The resin engagement portion 240e is formed when the liquid resin 140A that has reached the outer circumference of the frame 5 of the cell frame 1 flows into these resin grooves 255A, 255B, 255C, and 255D.

[0099] In addition, on each end plate 120A, 120B, the outer surface opposite to the surface facing the cell frame 1, that is, the surface on which the above-mentioned current-carrying terminal 182 is provided, and an annular recess 126 is formed near the periphery of the surface on which the opening 125 is formed, which does not communicate with the resin through holes 251A, 251B, 251C, 251D. The annular recess 126 is filled with liquid resin 140A that has flowed in from the outer circumference of the end plates 120A, 120B on the outer surface side of the end plates 120A, 120B, thereby forming the resin-forming engagement portion 140b, which will be described later.

[0100] In this embodiment, the annular recess 126 formed on the outer surface of each end plate 120A, 120B comprises a pair of straight sections 126a, 126c parallel to and opposite each other to the straight edges E11, E13 of the outer edge of the end plates 120A, 120B; a pair of straight sections 126b, 126d parallel to and opposite each other to the straight edges E12, E14; a curved section 126e connecting the straight sections 126a and 126b, located near the resin through-hole 251B, and curving convexly toward the center of the end plates 120A, 120B; and a curved section connecting the straight sections 126c and 126b to the resin through-hole 251B. The shape is a ring-shaped configuration in which a curved section 126f is located near the end plates 120A and 120B and curves convexly toward the center; a curved section 126g connects the straight sections 126c and 126d, is located near the resin through-hole 251D and is diagonally opposite to the curved section 126e and curves convexly toward the center of the end plates 120A and 120B; and a curved section 126h connects the straight sections 126a and 126d, is located near the resin through-hole 251A and is diagonally opposite to the curved section 126f and curves convexly toward the center of the end plates 120A and 120B. Furthermore, resin through holes 251A, 251B, 251C, 251D and resin flow channels 252A, 252B, 252C, 252D are formed between the curved portions 126e, 126f, 126g, 126h of the recess 126 and the through holes 211, 212, 221, 222.

[0101] Because such annular recesses 126 are formed on the outer surface of the end plates 120A and 120B, when forming the resin forming portion 140, the liquid resin 140A that flows from the resin through holes 251A, 251B, 251C, and 251D of the end plates 120A and 120B through the resin channels 252A, 252B, 252C, and 252D to the outer circumference of the end plates 120A and 120B flows from the outer circumference side, that is, from the outer edge E11, E12, E13, and E14 side of the end plates 120A and 120B, to the outer surface side opposite to the side (inner surface) facing the cell frame 1 of the end plates 120A and 120B, and fills the annular recesses 126.

[0102] In this embodiment, the cell frame 1 and end plates 120A, 120B with the above configuration are used, and multiple battery cells 110, each consisting of a cell frame 1 equipped with an electrode arrangement section 105 for arranging positive and negative electrodes 101 and a diaphragm 103, are stacked, and a pair of end plates 120A, 120B are placed at both ends in the stacking direction to form a laminate 130, which is then placed in a mold, and through holes 251A, 251A for resin in one of the end plates 120A, 120B By injecting liquid resin 140A from 1B, 251C, and 251D, the liquid resin 140A is spread throughout the entire periphery of the four outer edges E1, E2, E3, and E4 of each cell frame 1, and throughout the entire periphery of the edges E11, E12, E13, and E14 of each end plate 120A and 120B. In addition, the liquid resin 140A is spread in an annular manner around the outer peripheral edge of each end plate 120A and 120B on the side opposite to the cell frame 1 (inner side). Then, by cooling and solidifying the liquid resin 140A that has spread around the laminate 130, a resin-forming portion 140 is formed on the outer periphery of each cell frame 1 and each end plate 120A and 120B of the laminate 130.

[0103] Furthermore, in this embodiment, by allowing the liquid resin 140A to flow into the peripheral edges on the outer surface of each end plate 120A, 120B, the resin forming section 140 forms an annular resin forming end 140a on the peripheral edges on the outer surface of each end plate 120A, 120B. In addition, by providing an annular recess 126 on the peripheral edge on the outer surface of each end plate 120A, 120B, the liquid resin 140A that flows into the peripheral edges on the outer surface of each end plate 120A, 120B flows into the annular recess 126, and as the liquid resin 140A fills the recess 126, the resin forming section 140 forms an annular resin forming engagement portion 140b in the annular recess 126 on the outer surface of each end plate 120A, 120B.

[0104] Here, when forming the resin-molded part 140 by injection molding using liquid resin 140A, a shaft (rod) 311 made of metal or the like is inserted into the holes of the liquid supply manifolds 11, 12 and the liquid drainage manifolds 21, 22 of the cell frame 1 that constitute the laminate 130, the liquid supply through holes 411, 412 and the liquid drainage through holes 421, 422 of the diaphragm 103, and the liquid supply through holes 211, 212 and the liquid drainage through holes 221, 222 of the pair of end plates 120A, 120B. The shaft (rod) 311 is used to position and fix the cell frame 1, the diaphragm 103, and the end plates 120A, 120B of the laminate 130.

[0105] In particular, the cell frame 1 of this embodiment has positioning protrusions 153A, 153B, 153C, 153D and recesses 154A, 154B, 154C, 154D formed therein. In this embodiment, the positioning protrusions 153A, 153B, 153C, and 153D are formed within the resin channels 152A, 152B, 152C, and 152D of the cell frame 1, protruding from the surface of the frame 5 surrounding the resin channels 152A, 152B, 152C, and 152D. Furthermore, the recesses 154A, 154B, 154C, and 1534 are provided at positions opposite to the protrusions 153A, 153B, 153C, and 153D. From the perspective of the front and back surfaces of the cell frame 1, the protrusions 153A, 153B, 153C, and 153D and their corresponding recesses 154A, 154B, 154C, and 1534 are on opposite sides of each other.

[0106] Specifically, in the cell frame 1 of this embodiment, a projection 153A is provided in a resin channel 151A formed on the negative electrode side of the cell frame 1, and a projection 153C is provided in a resin channel 151C diagonally opposite to it. On the positive electrode side of one cell frame 1, a recess 154A is formed at a position corresponding to projection 153A, and a recess 154C is formed at a position corresponding to projection 153C. Furthermore, a projection 153B is provided in a resin channel 151B formed on the positive electrode side of the cell frame 1, and a projection 153D is provided in a resin channel 151D diagonally opposite to it. On the negative electrode side of one cell frame 1, a recess 154B is formed at a position corresponding to projection 153B, and a recess 154D is formed at a position corresponding to projection 153D.

[0107] With the cell frames 1, each equipped with positive and negative electrodes 101, stacked via a diaphragm 103, the cell frames 1 can be positioned by engaging the positioning protrusions 153A, 153B, 153C, and 153D formed on either the front or back surface of the frame 5 of the cell frame 1 with the recesses 154A, 154B, 154C, and 154D on the opposing surfaces of adjacent cell frames 1. This also allows the stacked cell frames 1 separated by the diaphragm 103 to be brought into close contact.

[0108] Furthermore, the end plates 120A and 120B of this embodiment also have positioning protrusions 253A, 253B, 253C, 253D and recesses 254A, 254B, 254C, 254D formed on them. In this embodiment, the positioning protrusions 253A, 253B, 253C, and 253D are formed within the resin channels 252A, 252B, 252C, and 252D on the inner surface of the end plates 120A and 120B, protruding from the surface of the frame 125 surrounding the resin channels 252A, 252B, 252C, and 252D. The recesses 254A, 254B, 254C, and 2534 are provided in the cell stack 100 at positions opposite to the protrusions 153A, 153B, 153C, and 153D of adjacent cell frames 1.

[0109] Specifically, in the end plate 120A of this embodiment, a projection 253A is provided in the resin channel 252A formed on the side of the end plate 120A facing the cell frame 1, and a projection 253C is provided in the resin channel 251C diagonally opposite to it, and a recess 254B is formed at a position corresponding to the projection 153B of the opposing cell frame 1, and a recess 254D is formed at a position corresponding to the projection 153D. In the end plate 120B of this embodiment, a projection 253B is provided within a resin channel 252B formed on the side of the end plate 120B facing the cell frame 1, and a projection 253D is provided within a resin channel 251D diagonally opposite to it. A recess 254A is formed at a position corresponding to a projection 153A of the opposing cell frame 1, and a recess 254C is formed at a position corresponding to a projection 153C. A projection 253B is provided within a resin channel 252B formed on the inner surface side of the end plate 120B, and a projection 253D is provided within a resin channel 251D diagonally opposite to it. A recess 254A is formed at a position corresponding to a projection 153A of the opposing cell frame 1, and a recess 254C is formed at a position corresponding to a projection 153C.

[0110] Then, with the cell frame 1 on which the positive and negative electrodes 101 are arranged and the end plates 120A and 120B adjacent to each other via a diaphragm 103, the positioning protrusions 153A, 153B, 153C, and 153D formed on the frame 5 of the cell frame 1 are fitted together with the recesses 254A, 254B, 254C, and 254D on the opposing surfaces of the end plates 120A and 120B, and the frame 5 of the cell frame 1 By fitting the recesses 154A, 154B, 154C, and 154D formed therein with the positioning protrusions 253A, 253B, 253C, and 253D on the opposing surfaces of the end plates 120A and 120B, the cell frame 1 and the end plates 120A and 120B are positioned, and the stacked layers of the cell frame 1 and the end plates 120A and 120B, separated by the diaphragm 103, can be brought into close contact.

[0111] In this way, when forming the resin-molded portion 140, multiple battery cells 110, each consisting of a cell frame 1 equipped with an electrode arrangement portion 105 for arranging positive and negative electrodes 101 and a diaphragm 103, are stacked, and a pair of end plates 120A and 120B are placed adjacent to each other at both ends in the stacking direction to form a stacked body 130. At this time, a shaft (rod) 311 made of metal or the like is inserted into the holes of the fluid supply manifolds 11 and 12 and the fluid drainage manifolds 21 and 22 of each cell frame 1, the fluid supply through holes 411 and 412 and the fluid drainage through holes 421 and 422 of each diaphragm 103, and the fluid supply through holes 211 and 212 and the fluid drainage through holes 221 and 222 of each end plate 120A and 120B. B, 154C, 154D are fitted together, and the protrusions 153A, 153B, 153C, 153D and recesses 154A, 154B, 154C, 154D formed on the cell frame 1 are fitted together with the protrusions 253A, 253B, 253C, 253D and recesses 254A, 254B, 254C, 254D formed on the opposing end plates 120A, 120B, thereby positioning and fixing the cell frame 1, diaphragm 103, and end plates 120A, 120B of the laminate 130.

[0112] In this embodiment, when injecting the liquid resin 140A to form the resin molding portion 140, the shafts (rods) 311 inserted through the liquid supply manifolds 11, 12 and liquid drainage manifolds 21, 22 of each cell frame 1, as well as the liquid supply through holes 211, 212 and liquid drainage through holes 221, 222 of each end plate 120A, 120B, are left protruding from the outer surface of each end plate 130, 120A, 120B. Then, within the mold, the liquid resin 140A reaches the outer circumference of the end plates 120A and 120B through the resin through-holes 251A, 251B, 251C, 251D and resin channels 152A, 152B, 152C, 152D of the end plates 120A and 120B, and further spreads to the area around the shaft 311 inserted through the liquid supply through-holes 211, 212 and the liquid drainage through-holes 221, 222 of the end plates 120A and 120B. This forms cylindrical resin forming openings 141A, 141B, 141C, 141D on the outer surface of each end plate 120A and 120B.

[0113] The details of the process for forming the resin-molded portion 140 in the cell stack 100 of this embodiment will be explained with reference to Figures 8 to 12. In this embodiment, first, as an assembly process, a plurality of cell frames 1 and a pair of end plates 120A, 120B with the above-described configuration are used to connect the holes of the liquid supply manifolds 11, 12 and the liquid drainage manifolds 21, 22 of the plurality of cell frames 1 constituting the laminate 130 to the liquid supply manifolds 11, 12 and the liquid drainage manifolds 21, 22 and the plurality of diaphragms 103. A shaft 311 is inserted through the liquid through-holes 411, 412 and the liquid drainage through-holes 421, 422 of each end plate 120A, 120B, and the liquid supply through-holes 211, 212 and liquid drainage through-holes 221, 222 of each end plate 120A, 120B. Multiple battery cells 110, each having a cell frame 1 with positive and negative electrodes 101 and a diaphragm 103, are stacked, and a pair of end plates 120A, 120B are placed at both ends in the stacking direction to assemble a laminate 130.

[0114] In this embodiment, a shaft (rod) 311 made of metal or the like is inserted into the holes of the fluid supply manifolds 11, 12 and the fluid drainage manifolds 21, 22 of each cell frame 1, the fluid supply through holes 411, 412 and the fluid drainage through holes 421, 422 of each diaphragm 103, and the fluid supply through holes 211, 212 and the fluid drainage through holes 221, 222 of each end plate 120A, 120B. In addition, projections 153A, 153B, 153C, 153D and recesses 154A, 154B are formed on each cell frame 1. By fitting 154C and 154D together, and by fitting the protrusions 153A, 153B, 153C, 153D and recesses 154A, 154B, 154C, 154D formed on the cell frame 1 together with the protrusions 253A, 253B, 253C, 253D and recesses 254A, 254B, 254C, 254D formed on the opposing end plates 120A and 120B, the cell frame 1, diaphragm 103, and end plates 120A and 120B of the laminate 130 are positioned and fixed.

[0115] Then, as a resin forming process, in that state, injection molding is performed in which liquid resin 140A is injected and filled through resin through holes 251A, 251B, 251C, and 251D of one of the pair of end plates 120A and 120B that are located on both sides of the laminate 130 in a predetermined mold.

[0116] In this way, by inserting the shaft 311 through the fluid supply through holes 211, 212 and fluid drainage through holes 221, 222 of each end plate 120A, 120B of the laminate 130, the fluid supply manifolds 11, 12 and fluid drainage manifolds 21, 22 of each cell frame 1, and the fluid supply through holes 411, 412 and fluid drainage through holes 421, 422 of each diaphragm 103, and then stacking and setting it in the mold, the cell frames 1, diaphragms 103, and end plates 120A, 120B that constitute the laminate 130 can be stacked with minimal misalignment and with high precision, and the stacks can be tightly fixed together, resulting in high-precision stacking with minimal misalignment of the cell frames 1, diaphragms 103, and end plates 120A, 120B with good assembly efficiency. Furthermore, by fitting the protrusions 153A, 153B, 153C, 153D and recesses 154A, 154B, 154C, 154D formed on each cell frame 1, and by fitting the protrusions 153A, 153B, 153C, 153D and recesses 154A, 154B, 154C, 154D formed on the cell frame 1 with the protrusions 253A, 253B, 253C, 253D and recesses 254A, 254B, 254C, 254D formed on the opposing end plates 120A, 120B, it is possible to perform high-precision lamination with minimal misalignment of the cell frame 1.

[0117] In this embodiment, the shaft 311, which is inserted through the fluid supply through holes 211, 212 and drainage through holes 221, 222 of each end plate 120A, 120B of the laminate 130, the fluid supply manifolds 11, 12 and drainage manifolds 21, 22 of each cell frame 1, and the fluid supply through holes 411, 412 and drainage through holes 421, 422 of each diaphragm 103, is made of metal or the like, and at least one end of its length is tapered toward the tip to facilitate insertion into the holes.

[0118] Thus, when forming the resin-molded portion 140 in the cell stack 100 of this embodiment, four shafts 311 are inserted through the liquid supply through holes 211, 212 and liquid drainage through holes 221, 222 provided at the four corners of the rectangular front view of each end plate 120A, 120B, the liquid supply manifolds 11, 12 and liquid drainage manifolds 21, 22 provided at the four corners of the rectangular front view of each cell frame 1, and the liquid supply through holes 411, 412 and liquid drainage through holes 421, 422 provided at the four corners of the rectangular front view of each diaphragm 103, and the stacks are made by inserting these shafts 311 through the Then, in that state, liquid resin 140A is injected and filled into a predetermined mold through resin through holes 251A, 251B, 251C, and 251D of either of the pair of end plates 120A and 120B, thereby circulating the liquid resin 140A from the inside of the laminate 130 toward the outer periphery, spreading the liquid resin 140A to all four surrounding surfaces of the roughly rectangular laminate 130, excluding the two end faces on both sides in the longitudinal direction, and also spreading the liquid resin 140A to parts of the two end faces on both sides in the longitudinal direction of the laminate 130.

[0119] In more detail, as part of the liquid resin filling process, the liquid resin 140A injected from the resin through-holes 251A, 251B, 251C, and 251D of one of the end plates 120A and 120B flows through the resin through-holes 151A, 151B, 151C, and 151D of each stacked cell frame 1 and the resin through-holes 451, 452, 461, and 462 of each diaphragm, and flows into the resin channels 152A, 152B, 152C, and 152D that connect the resin through-holes 151A, 151B, 151C, and 151D with the outer edge of each cell frame 1. Furthermore, because the resin channels 152A, 152B, 152C, and 152D, which are in communication with the resin through holes 151A, 151B, 151C, and 151D of each cell frame 1, extend outward from the cell frame 1, the liquid resin 140A that flows from each resin through hole 151A, 151B, 151C, and 151D of each cell frame 1 into the resin channels 152A, 152B, 152C, and 152D of each cell frame 1 flows through the resin channels 152A, 152B, 152C, and 152D, flows to the outer circumference of the cell frame 1, and spreads throughout the entire perimeter of the stacked cell frames 1.

[0120] Furthermore, the liquid resin 140A injected from the resin through-holes 251A, 251B, 251C, and 251D of one of the end plates 120A and 120B flows through the resin through-holes 151A, 151B, 151C, and 151D of each laminated cell frame 1 and the resin through-holes 451, 452, 461, and 462 of each diaphragm, and further reaches the resin through-holes 251A, 251B, 251C, and 251D of the other end plate 120A and 120B. Then, in each end plate 120A, 120B, the liquid resin 140A that has flowed through the resin through holes 251A, 251B, 251C, 251D flows into resin channels 252A, 252B, 252C, 252D that connect the resin through holes 251A, 251B, 251C, 251D to the outer edge. Because the resin channels 252A, 252B, 252C, and 252D in each end plate 120A and 120B are connected to the resin through holes 251A, 251B, 251C, and 251D and extend outwards from the end plates 120A and 120B, the liquid resin 140A that flows from the resin through holes 251A, 251B, 251C, and 251D in each end plate 120A and 120B into the resin channels 252A, 252B, 252C, and 252D of each end plate 120A and 120B flows through the resin channels 252A, 252B, 252C, and 252D and flows outwards to the outer circumference of the end plates 120A and 120B, spreading throughout the entire outer periphery.

[0121] Specifically, as shown in Figure 9, the liquid resin 140A that flows from the resin through-hole 151A formed in each cell frame 1 into the resin channel 152A flows towards the side E4 of the outer edge of the cell frame 1, the liquid resin 140A that flows from the resin through-hole 151B into the resin channel 152B flows towards the side E2 of the outer edge of the cell frame 1, the liquid resin 140A that flows from the resin through-hole 151C into the resin channel 152C flows towards the side E2 of the outer edge of the cell frame 1, and the liquid resin 140A that flows from the resin through-hole 151D into the resin channel 152D flows towards the side E4 of the outer edge of the cell frame 1.

[0122] Then, on edge E1 of cell frame 1, the liquid resin 140A that flowed in through the resin through hole 151A and through the resin channel 152A merges with the liquid resin 140A that flowed in through the resin through hole 151B and through the resin channel 152B. On edge E2 of cell frame 1, the liquid resin 140A that flowed in through the resin through hole 151B and through the resin channel 152B merges with the liquid resin 140A that flowed in through the resin through hole 151C and through the resin channel 152C. On side E3 of cell frame 1, the liquid resin 140A that flowed in through the resin through hole 151C and through the resin channel 152C merges with the liquid resin 140A that flowed in through the resin through hole 151D and through the resin channel 152D. On side E4 of cell frame 1, the liquid resin 140A that flowed in through the resin through hole 151D and through the resin channel 152D merges with the liquid resin 140A that flowed in through the resin through hole 151A and through the resin channel 152A. In this way, the liquid resin 140A spreads throughout the entire perimeter of the four outer edges E1, E2, E3, and E4 of each cell frame 1.

[0123] In particular, in this embodiment, the resin channels 152A and 152C of the cell frame 1 are provided at two opposing corners on one side of the rectangular cell frame 1, and the resin channels 152B and 152D of the cell frame 1 are provided at two other opposing corners on the other side of the cell frame 1. This allows the liquid resin 140A to be efficiently and uniformly distributed across the four sides E1, E2, E3, and E4 around the cell frame 1. At this time, the resin channels 152A, 152B, 152C, and 152D, which are in communication with the resin through holes 151A, 151B, 151C, and 151D, extend toward one of the two adjacent sides of the outer edge of the cell frame 1 that form the corner of the cell frame 1. In particular, the liquid resin 140A from the resin through holes 151A, 151B, 151C, and 151D flows toward the vertical sides E2 and E4 of the cell frame 1. As a result, the liquid resin 140A that merges with the horizontal sides E1 and E3 of the cell frame 1 overflows and is less likely to enter the electrolyte channels 31, 32, 41, and 42.

[0124] Furthermore, as shown in Figure 10, the liquid resin 140A that flows into the resin channel 252A from the resin through-hole 251A formed in each end plate 120A, 120B flows towards the edge E14 side of the outer edge of the end plates 120A, 120B, the liquid resin 140A that flows into the resin channel 252B from the resin through-hole 251B flows towards the edge E12 side of the outer edge of the end plates 120A, 120B, the liquid resin 140A that flows into the resin channel 252C from the resin through-hole 251C flows towards the edge E12 side of the outer edge of the end plates 120A, 120B, and the liquid resin 140A that flows into the resin channel 252D from the resin through-hole 251D flows towards the edge E14 side of the outer edge of the end plates 120A, 120B.

[0125] Then, on the edge E11 of the end plates 120A and 120B, the liquid resin 140A that flowed in from the resin through hole 251A through the resin channel 252A and the liquid resin 140A that flowed in from the resin through hole 251B through the resin channel 252B merge, and on the edge E12 of the end plates 120A and 120B, the liquid resin 140A that flowed in from the resin through hole 251B through the resin channel 252B and the liquid resin 140A that flowed in from the resin through hole 251C through the resin channel 252C merge. On the edge E13 of the end plates 120A and 120B, the liquid resin 140A that flowed in through the resin through hole 251C and through the resin channel 252C merges with the liquid resin 140A that flowed in through the resin through hole 251D and through the resin channel 252D. On the edge E14 of the end plates 120A and 120B, the liquid resin 140A that flowed in through the resin through hole 251D and through the resin channel 252D merges with the liquid resin 140A that flowed in through the resin through hole 251A and through the resin channel 252A. In this way, the liquid resin 140A spreads throughout the entire perimeter of the four outer edges E11, E12, E13, and E14 of each end plate 120A and 120B.

[0126] In particular, in this embodiment, the resin channels 252A and 252C of each end plate 120A and 120B are provided at two opposing corners on one side of the rectangular end plate 120A and 120B, and the resin channels 152B and 152D of the end plate 120A and 120B are provided at two other opposing corners on the other side of the end plate 120A and 120B. As a result, the liquid resin 140A can be efficiently and uniformly distributed to the edges E11, E12, E13, and E14 around the end plates 120A and 120B. At this time, the resin channels 252A, 252B, 252C, and 252D, which are in communication with the resin through holes 251A, 251B, 251C, and 251D, extend toward one of the two adjacent sides of the outer edge of the end plates 120A and 120B that form the corners of the end plates 120A and 120B. In particular, the liquid resin 140A from the resin through holes 251A, 251B, 251C, and 251D flows toward the vertical edges E12 and E14 of the end plates 120A and 120B. As a result, the liquid resin 140A that merges at the lateral edges E11 and E13 of the end plates 120A and 120B is less likely to overflow and enter the electrolyte channels 231, 232, 241, and 242.

[0127] In this way, the liquid resin 140A that flows around each cell frame 1 and each end plate 120A, 120B spreads throughout the entire outer circumference of the laminate 130, in which the cell frames 1 are stacked with a thin diaphragm 103 in between, and a pair of end plates 120A, 120B are positioned at both ends in the stacking direction. Furthermore, in the case of the pair of end plates 120A, 120B positioned on both sides in the stacking direction of the laminate 130, the liquid resin 140A that flows around their outer circumference also flows onto the outer circumference of the cell frame 1 on the side opposite to the opposing side. Furthermore, an annular recess 126 is formed on the outer circumferential surface of the end plates 120A and 120B, allowing the liquid resin 140A to spread from the outer circumferential surface of the end plates 120A and 120B to the position of the annular recess 126. In addition, by allowing the shaft (rod) 311 through which the laminate 130 is inserted to protrude, the liquid resin 140A also spreads around the shaft (rod) 311.

[0128] Then, liquid resin 140A is filled into the entire outer circumference of the laminate 130, and liquid resin 140A is also filled into the outer surfaces of the pair of end plates 120A and 120B from the outer circumference up to the position of the annular recess 126. Furthermore, liquid resin 140A is also filled around the shaft 311 that protrudes from the outer surfaces of the pair of end plates 120A and 120B. After this, a cooling process is performed, and then the molded product, which is the laminate 130 with the resin-forming portion 140 formed around it, is demolded. At this time, as a removal process, the shaft 311 that penetrates the laminate 130 is pushed out, the shaft 311 is removed from the laminate 130, and the molded product of the laminate 130 with the resin-forming portion 140 formed around it with the shaft 311 removed is taken out.

[0129] As the liquid resin 140A cools and solidifies, a resin forming portion 140 is formed around the laminate 130, and the cell stack 100, which has been bonded, is sealed airtight by the resin forming portion 140 that forms around the laminate 130, thereby bonding the layers of the laminate 130 together. In other words, all four outer surfaces of the laminate 130 are covered with the resin forming portion 140, and the entire perimeter of the laminate 130 perpendicular to the lamination direction is surrounded by the resin forming portion 140, so that the cell frames 1 and the cell frames 1 and end plates 120A and 120B are bonded and sealed through the diaphragm 103 of the laminate 130, and adhesion is maintained.

[0130] The resin-forming portion 140 surrounding the laminate 130 is, for example, about 1 mm to 5 mm thick, and as shown in Figure 13, is roughly rectangular in shape. Furthermore, as liquid resin 140A flows into the outer surfaces of the pair of end plates 120A and 120B, an annular (frame-like) shape is formed around the periphery of both side end faces in the lamination direction of the laminate 130, that is, on the outer surfaces of the pair of end plates 120A and 120B arranged on both sides in the lamination direction of the laminate 130, thus giving the rectangular tubular end portions 140a annular (frame-like) resin-forming ends 140a at both ends.

[0131] Furthermore, as shown in Figure 10, in this embodiment, an annular recess 126 is provided on the peripheral edge of the outer surface of a pair of end plates 120A and 120B, and liquid resin 140A is filled therein, so that the resin-formed end portion 140a formed on the outer surface of the pair of end plates 120A and 120B has an annular resin-formed engaging portion 140b that engages with the annular recess 126.

[0132] In other words, in this embodiment, the cell stack 100 has a pair of end plates 120A and 120B arranged on both sides of the stacking direction of the laminate 130. Liquid resin 140A flows into an annular recess 126 provided in the pair of end plates 120A and 120B from the outer circumference of the end plates 120A and 120B, filling the recess and solidifying in that state, thereby forming an annular resin-forming engagement portion 140b that engages with the annular recess 126. Therefore, the resin-forming engagement portion 140b, which is the edge of the resin-forming end 140a formed on the end plate 120A, 120B side of the resin-forming portion 140 that surrounds the laminate 130, engages with the end plates 120A, 120B. This closes the edge of the resin-forming end 140a within the annular recess 126 of the end plates 120A, 120B, making it difficult for the edge of the resin-forming end 140b of the resin-forming portion 140 to peel off from the end plates 120A, 120B even when the cell stack 100 is subjected to vibration or other shocks. In other words, the engagement of the resin-forming engagement portion 140b, which is the edge of the resin-forming end 140a, with the end plates 120A, 120B makes it difficult for a gap to form between the edge of the resin-forming end 140a and the end plates 120A, 120B. This further prevents leakage of electrolyte from the edge of the resin-formed end portion 140a, improving liquid tightness.

[0133] Furthermore, liquid resin 140A is also filled around the four shafts 311 that protrude from the outer surface of the pair of end plates 120A and 120B after being inserted through the laminate 130, so that the resin-forming end portion 140a formed on the outer surface of the pair of end plates 120A and 120B has cylindrical resin-forming openings 141A, 141B, 141C, and 141D.

[0134] In other words, in this embodiment, when forming the resin-molded portion 140, a shaft 311 is inserted through the fluid supply through holes 211, 212 and fluid drainage through holes 221, 222 of each end plate 120A, 120B, the fluid supply manifolds 11, 12 and fluid drainage manifolds 21, 22 of each cell frame 1, and the fluid supply through holes 411, 412 and fluid drainage through holes 421, 422 of each diaphragm 103, and a pair of end plates 1 The end plates 20A and 120B are set in the mold with both ends of the shaft 311 protruding from the outer surfaces, and liquid resin 140A is allowed to flow around the shaft 311 that protrudes from the outer surfaces of the pair of end plates 120A and 120B, thereby forming cylindrical resin-forming openings 141A, 141B, 141C, and 141D on the resin-forming ends 140a formed on the peripheral edges of the outer surfaces of the pair of end plates 120A and 120B.

[0135] Furthermore, the cylindrical resin-formed openings 141A, 141B, 141C, and 141D formed at the four corners on the outer surface of the pair of end plates 120A and 120B are located in positions corresponding to the through-holes 211 and 212 for electrolyte supply in the pair of end plates 120A and 120B. As such, they serve as electrolyte inlets through which electrolyte supplied from the electrolyte tank flows into the through-holes 211 and 212 of the pair of end plates 120A and 120B, or through which electrolyte flows out to the outside from the drainage through-holes 221 and 222 of the pair of end plates 120A and 120B.

[0136] Specifically, the resin-molded openings 141A and 141B formed on the outer surfaces of a pair of end plates 120A and 120B located at both ends of the laminated body 130 in the stacking direction communicate with the electrolyte supply through holes 211 and 212 of the end plates 120A and 120B, thereby forming inlets for the electrolyte supplied from the electrolyte tank by a pump into the cell stack 100. The resin-molded openings 141C and 141D communicate with the drainage through holes 221 and 222 of the end plates 120A and 120B, thereby forming outlets for the electrolyte to be discharged into the electrolyte tank. When forming a redox flow battery, tubing for circulating the electrolyte between the electrolyte tank and the cell stack 100 is connected to these resin-molded openings 141A, 141B, 141C, and 141D.

[0137] In addition, as shown in Figure 13, the resin through holes 251A, 251B, 251C, 251D in the end plates 120A, 120B and the resin through holes 151A, 151B, 151C, 151D in the cell frame 1, as well as the resin channels 252A, 252B, 252C, 252D in the end plates 120A, 120B and the resin channels 152A, 152B, 152C, 152D in the cell frame 1, are filled with liquid resin 140A and then cooled and solidified, resulting in the laminate 13 Within the 0, there is a resin-filled portion 140d formed by filling the resin through holes 251A, 251B, 251C, 251D of the end plates 120A, 120B and the resin through holes 151A, 151B, 151C, 151D of the cell frame 1, and a resin-filled portion 140c formed by filling the resin channels 252A, 252B, 252C, 252D of the end plates 120A, 120B and the resin channels 152A, 152B, 152C, 152D of the cell frame 1.

[0138] Specifically, the cylindrical resin forming section 140 surrounding the laminate 130 has a resin filling section 140d that connects the resin forming ends 140a formed at both ends in the lamination direction, extending in the lamination direction, formed by filling the resin through holes 251A, 251B, 251C, 251D of the end plates 120A, 120B and the resin through holes 151A, 151B, 151C, 151D of the cell frame 1 with resin, and a resin filling section 140c between the resin filling section 140a and the surrounding surface of the cylinder, formed by filling the resin channels 252A, 252B, 252C, 252D of the end plates 120A, 120B and the resin channels 152A, 152B, 152C, 152D of the cell frame 1 with resin. Furthermore, the resin-filled portions 140c that connect the resin-formed ends 140a formed at both ends in the stacking direction, and the 140d that connect the resin-filled portions 140a to the surrounding surface of the cylinder, are formed at the four corners of the rectangular cylinder.

[0139] Furthermore, in this embodiment, resin grooves 155A, 155B, 155C, and 155D are provided near the manifolds 11, 12, 21, and 22 at the outer edge of the surface of the cell frame 1, into which the liquid resin 140A that has reached the outer periphery of the end plates 120A and 120B enters. As a result, the liquid resin 140A that has reached the outer periphery of the frame 5 of the cell frame 1 also flows into these resin grooves 155A, 155B, 155C, and 155D. Therefore, the outer edge of the surface of the cell frame 1, near the manifolds 11, 12, 21, and 22, has a resin engagement portion 140e formed by the filling of resin into the resin grooves 155A, 155B, 155C, and 155D.

[0140] Furthermore, in this embodiment, resin grooves 255A, 255B, 255C, and 255D are provided near the through holes 211, 212, 221, and 222 at the outer edges of the surfaces of the end plates 120A and 120B, into which the liquid resin 140A that has reached the outer periphery of the end plates 120A and 120B enters. As a result, the liquid resin 140A that has reached the outer periphery of the end plates 120A and 120B also flows into these resin grooves 255A, 255B, 255C, and 255D. In particular, at the outer edges of the surfaces of the end plates 120A and 120B facing the cell frame 1, near the through holes 211, 212, 221, and 222, there is a resin engagement portion 140e formed by filling the resin grooves 255A, 255B, 255C, and 255D with resin.

[0141] Thus, in this embodiment, the cell frame 1 and end plates 120A and 120B have resin engaging parts 140e formed by filling resin into resin grooves 155A, 155B, 155C, 155D and resin grooves 255A, 255B, 255C, 255D on their outer edges near the manifolds 11, 12, 21, 22 and through holes 211, 212, 221, 222 on their surfaces, and the cell frame 1 and end plates 120A and 120B with resin. This ensures that the cell frame 1 and end plates 120A and 120B are firmly fixed and displacement is prevented. Therefore, mixing and leakage of positive and negative electrolytes due to displacement or deformation of the cell frame 1 and end plates 120A and 120B can be prevented.

[0142] Furthermore, in this embodiment, the cell frame 1, which has a resin-forming portion 140 formed around it, has resin-filled portions 140c formed in the resin channels 152A, 152B, 152C, and 152D, and these resin-filled portions 140c are located between the fluid supply manifolds 11, 12 and the fluid drainage manifolds 21, 22 of the cell frame 1 and the electrolyte channels 31, 32, 41, 42. As a result, the difference in height between the resin-filled portions 140c filled in the resin channels 152A, 152B, 152C, and 152D and the surrounding surface of the frame 5 of the cell frame 1 makes it possible to prevent the electrolyte flowing through the fluid supply manifolds 11, 12 and the fluid drainage manifolds 21, 22 from mixing with an electrolyte of the opposite polarity to the positive and negative polarity of that electrolyte.

[0143] Similarly, in the end plates 120A and 120B, where the resin-forming portion 140 is formed around the periphery, a resin-filled portion 140c is formed in the resin flow channels 252A, 252B, 252C, and 252D. This resin-filled portion 140c is located between the liquid supply through-holes 211, 212 and the liquid drainage through-holes 221, 222 of the end plates 120A and 120B and the electrolyte flow channels 231, 232, 241, and 242. As a result, the step difference between the resin-filled portion 140c filled in the resin flow channels 252A, 252B, 252C, and 252D and the surrounding surface of the frame 5 of the cell frame 1 makes it possible to prevent the electrolyte flowing through the liquid supply through-holes 211, 212 and the liquid drainage through-holes 221, 222 from mixing with an electrolyte of the opposite polarity to the positive and negative polarity of that electrolyte. Therefore, a decrease in battery efficiency can be prevented.

[0144] The cell stack 100 of this embodiment, manufactured in this manner, comprises a cell frame 1 consisting of positive and negative electrodes 101, an electrode arrangement section 105 on which the positive and negative electrodes 101 are arranged, and a frame 5 provided around the electrode arrangement section 105, a diaphragm 103 disposed between the positive and negative electrodes 101, a pair of end plates 120A and 120B arranged at both ends in the stacking direction of a stack of multiple battery cell sections 110, and a resin-molded section 140 that surrounds a stack 130 on which multiple battery cell sections 110 are stacked and a pair of end plates 120A and 120B are arranged at both ends in the stacking direction, thereby integrally sealing the spaces between the cell frames 1 and between the cell frames 1 and the end plates 120A and 120B.

[0145] The cell stack 1 of this embodiment is formed by stacking multiple battery cells 110, each cell consisting of positive and negative electrodes 101, an electrode arrangement section 105 for arranging the positive and negative electrodes 101, a frame 5 provided around the electrode arrangement section 105, and a diaphragm 103 arranged between the positive and negative electrodes 101. A pair of end plates 120A and 120B are placed at both ends in the stacking direction to form a stacked body 130. Liquid resin 140A is then filled around the stacked body 130 in a mold and cooled and solidified, thereby integrally covering and sealing the stacked body 130 with a resin forming section 140.

[0146] In this way, by filling the periphery of the laminate 130 with liquid resin 140A in a mold and cooling and solidifying it, a resin-formed portion 140 is formed and bonded around the laminate 130, and the layers of the laminate 130 are integrally sealed by the resin-formed portion 140. This eliminates the need to place sealing members such as O-rings or packings between the layers of the cell frame 1, etc., or to weld the layers of the cell frame 1, etc., as the resin-formed portion 140 is formed and bonded around the outer periphery of the laminate 130 to create an integral seal. As a result, the number of parts is reduced, and the work and man-hours required to precisely position sealing members and conductive members for welding are eliminated. Therefore, cost reduction is possible, and the effort required to seal the cell stack 100 is reduced, resulting in improved production efficiency. Furthermore, the bonding between the outer perimeter of the laminate 130 and the resin-formed portion 140 is achieved because the resin-formed portion 140, which is formed on the outer perimeter of the laminate 130, is molded by filling the outer perimeter of the laminate 130 with liquid resin 140A. As a result, the laminate 130 and the resin-formed portion 140 are tightly bonded together, and the lamination is integrally sealed. Therefore, because the resin-formed portion 140 is tightly bonded to the outer perimeter of each cell frame 1 and each end plate 120A, 120B, the sealing performance is high, and the reliability of the sealing is improved.

[0147] Furthermore, in this embodiment, the cell stack 100 does not use sealing members such as O-rings or gaskets between the cell frames 1, nor does it use welding between the cell frames 1. As a result, the stacked structure of the battery cell sections 110 is thin, which allows current to flow more easily and improves battery efficiency. It also enables miniaturization and space saving. In addition, since sealing members and welding between cell frames 1 are not required, the design freedom of the frame 5 of the cell frame 1 is increased, and miniaturization is possible by reducing the area of ​​the frame 5.

[0148] Furthermore, since the diaphragm 103, which is placed between cell frames 1, does not tear due to contact with sealing members, etc., a decrease in the charge / discharge rate due to mixing of positive and negative electrolytes caused by tearing of the diaphragm 103 is less likely to occur.

[0149] In particular, in this embodiment, ribs 115 are formed in the electrolyte flow paths 31, 41, 32, 42 of the cell frame 1 on the connection side with the manifolds 11, 12, 21, 22, thereby reinforcing the area around the manifolds 11, 12, 21, 22 and preventing deformation of the cell frame 1 due to the internal pressure of the electrolyte flowing through the manifolds 11, 12, 21, 22 and the internal pressure of the liquid resin 140A flowing through the resin through holes 151A, 151B, 151C, 151D and the resin flow paths 152A, 152B, 152C, 152D. Furthermore, the internal pressure of the electrolyte flowing through manifolds 11, 12, 21, 22 and the internal pressure of the liquid resin 140A flowing through resin through-holes 151A, 151B, 151C, 151D and resin flow paths 152A, 152B, 152C, 152D prevent adjacent diaphragms 103 from falling into flow paths 31, 32, 41, 42 and being damaged. Thus, the durability of the cell stack 100 can be improved. Moreover, it is possible to prevent displacement of the diaphragms 103 by holding down the diaphragms 103 positioned between adjacent cell frames 1 in the cell stack 100. Thus, a decrease in charge / discharge rate due to mixing of positive and negative electrolytes can be prevented.

[0150] Furthermore, in the electrolyte flow paths 231, 232, 241, and 242 of the end plates 120A and 120B, ribs 115 are formed on the connection side with the electrolyte through-holes 211, 212, 221, and 222. This reinforces the area around the electrolyte through-holes 211, 212, 221, and 222, preventing deformation of the end plates 120A and 120B due to the internal pressure of the electrolyte flowing through the electrolyte through-holes 211, 212, 221, and 222, as well as the internal pressure of the liquid resin 140 flowing through the resin through-holes 251A, 251B, 251C, and 251D and the resin flow paths 252A, 252B, 252C, and 252D. In addition, it is possible to prevent displacement of the diaphragm 130, which is positioned between adjacent cell frames 1 in the cell stack 100, by holding it in place. Furthermore, the internal pressure of the electrolyte flowing through the electrolyte through-holes 211, 212, 221, and 222, as well as the internal pressure of the liquid resin 140 flowing through the resin through-holes 251A, 251B, 251C, 251D and the resin flow paths 252A, 252B, 252C, 252D, can prevent adjacent diaphragms from falling into the flow paths 231, 232, 241, and 242. Thus, the durability of the cell stack 100 can be improved.

[0151] In this embodiment, the cell stack 100 differs from conventional cell stacks, which have a fastening mechanism that clamps both ends of the laminate 130 with heavy metal end plates and fastens the laminate 130 with long bolts and nuts. Instead, the cell stack 100 is formed by filling the surrounding surface of the laminate 130 with liquid resin 140A by injection molding, cooling and solidifying it to form a resin-formed portion 140 that encloses the surface of the laminate 130, thereby restraining and fixing the laminate 130. As a result, the absence of a metal fastening mechanism makes it lighter, and the number of assembly steps and parts is reduced, making it easier to manufacture, lowering costs, and improving productivity. Because a metal fastening mechanism is not required, there is no concern about a decrease in sealing performance due to bolt loosening caused by the internal pressure of the electrolyte, and the laminate 130 is less likely to deform under the internal pressure of the electrolyte, so the high sealing performance is not easily reduced. Furthermore, by eliminating the placement of gaskets and the like, the battery cell section 110 becomes thinner (thin-walled), which reduces electrical resistance, leading to improved output, as well as miniaturization and space saving. In addition, since the cell stack 100 of this embodiment has its laminated body 130 bound together by a resin molded section 140, it is easy to disassemble, and its components, including the resin molded section 140, are also easy to recycle.

[0152] Furthermore, in this embodiment, the cell stack 100 is formed by molding using liquid resin 140A, and the laminate 130 is integrally surrounded and sealed by the resin forming part 140. The entire resin forming part 140 surrounding the laminate 130 can absorb changes in expansion and contraction caused by temperature changes and internal pressure of the laminate 130. Therefore, vibrations and shocks during transportation to the installation site of the redox flow battery, as well as stresses caused by thermal expansion of the cell frame 1 due to the internal pressure of the electrolyte during charging and discharging and temperature rise inside the cell stack 100, make it difficult for the cell frame 1 to be subjected to partial loads, and displacement and deformation of the cell frame 1 are unlikely to occur. Therefore, leakage of the electrolyte due to displacement and deformation of the cell frame 1 is unlikely, and mixing of positive and negative electrolytes is unlikely, thus preventing a decrease in charge and discharge efficiency.

[0153] In addition, the cell stack 100 of this embodiment is sealed all at once by covering the periphery of the laminate 130 with a resin-molded portion 140, and the laminate 130 is fixed in place without a fastening mechanism that clamps both ends of the laminate 130 with heavy metal end plates and tightens the laminate 130 with long bolts and nuts. As a result, high surface pressure is not easily applied to the cell frame 1, making the cell frame 1 less prone to deformation, and thus reducing the likelihood of electrolyte leakage caused by deformation of the cell frame 1. Therefore, the reliability of the sealing is improved, and the electrolyte flowing through the cell stack 100 is less likely to leak to the outside over time.

[0154] Furthermore, in this embodiment, the cell stack 100 has a resin forming section 140 formed around the laminate 130, which has annular (frame-shaped) resin forming ends 140a and 140b formed at both ends in the stacking direction of the laminate 130, and resin forming openings 141A, 141B, 141C, and 141D formed thereon. As a result, it is not necessary to create a separate supply and drainage section for supplying electrolyte to the manifolds 11 and 12 of the cell frame 1 or for draining electrolyte discharged from the manifolds 21 and 22 of the cell frame 1. Therefore, the number of parts is reduced, costs can be lowered, and production efficiency is improved. In other words, since the resin forming section 140 has cylindrical resin forming ports 141A, 141B, 141C, and 141D on the outer surface side of each end plate 120A and 120B through which the electrolyte is supplied and drained, it is possible to simultaneously form the supply and drain ports for the electrolyte that flows to the cell frame 1 along with sealing the laminate 130, thereby increasing productivity and reducing costs.

[0155] Thus, the cell stack 100 of this embodiment allows for assembly with fewer parts and fewer man-hours, reducing assembly effort, lowering costs, and increasing productivity.

[0156] Furthermore, the cell stack 100 of this embodiment includes resin through holes 151A, 151B, 151C, 151D and resin channels 152A, 152B, 152C, 152D provided in the cell frame 1, resin through holes 451, 452, 461, 462 provided in the diaphragm 103, and resin through holes 251A, 251B, 251C, 251D and resin channels 252A, 252B, 252C, 252D provided in the end plates 120A, 120B. By circulating the liquid resin 140A, that is, by circulating the liquid resin 140A from the inside to the outside of the laminate 130, the liquid resin 140A is distributed to the outer circumference of the laminate 130. In the flow paths of the liquid resin 140A within the cell frame 1 and the end plates 120A and 120B, resin filling sections 140c and 140d are formed, which are integrally continuous with the resin forming section 140 formed around the laminate 130. In other words, the resin forming section 140 formed around the laminate 130 has resin filling sections 140c and 140d that are integrally continuous with it inside the laminate 130. As a result, the laminate 130 is more firmly restrained, and displacement and deformation of the cell frame 1 are less likely to occur due to stress caused by the internal pressure of the electrolyte during charging and discharging when the electrolyte is circulated in the cell stack 100, or due to thermal expansion of the cell frame 1 caused by the temperature rise inside the cell stack 100. Therefore, electrolyte leakage due to deformation of the cell frame 1 is less likely to occur.

[0157] In particular, in the cell stack 100 of this embodiment, the resin-filled portions 140c filled in the resin channels 152A, 152B, 152C, and 152D of the cell frame 1 are provided at two opposing corners on one side of the rectangularly shaped cell frame 1 and at two other opposing corners on the other side, so that the liquid resin 140A can be efficiently and uniformly distributed around the cell frame 1. Similarly, in the end plates 120A and 120B, the resin-filled portions 140c filled in the resin channels 252A, 252B, 252C, and 252D are provided at two opposing corners on one side of the rectangularly shaped end plates 120A and 120B and at two other opposing corners on the other side, so that the liquid resin 140A can be efficiently and uniformly distributed around the end plates 120A and 120B. Therefore, moldability is improved, the reliability of the sealing performance by the resin-molded part 140 is enhanced, and misalignment and deformation of the cell frame 1 and end plates 120A and 120B are prevented.

[0158] Furthermore, in this embodiment, the resin-forming portion 140 of the cell stack 100 has an annular resin-forming end 140a formed on the peripheral edge of the outer surface of each end plate 120A, 120B, thus improving the reliability of the sealing performance. In particular, since the resin-molded portion 140 has a resin-engaging portion 140b that engages with the end plates 120A and 120B on the outer surface side of each end plate 120A and 120B, peeling from the end plates 120A and 120B is less likely to occur, and sealing performance can be further improved.

[0159] As described above, the cell stack 100 of the above embodiment is a cell stack 100 in which a plurality of battery cells 110 are stacked, each cell frame 1 consisting of positive and negative electrodes 101, a diaphragm 103 disposed between the positive and negative electrodes 101, an electrode arrangement portion 105 on which the positive and negative electrodes 101 are arranged, and a frame 5 provided around the electrode arrangement portion 105. A pair of end plates 120A and 120B are arranged at both ends of the stacked battery cells 110 in the stacking direction, and the stacked body 130 consisting of the plurality of stacked battery cells 110 and the pair of end plates 120A and 120B arranged at both ends in the stacking direction is integrally sealed by a resin molded portion 140 formed around it.

[0160] In other words, the cell stack 100 of the above embodiment comprises a plurality of battery cells 110, each consisting of positive and negative electrodes 101, a diaphragm 103 disposed between the positive and negative electrodes 101, and a cell frame 1 consisting of an electrode arrangement section 105 on which the positive and negative electrodes 101 are arranged and a frame 5 provided around the electrode arrangement section 105; a pair of end plates 120A and 120B arranged at both ends in the stacking direction of the plurality of stacked battery cells 110; and a resin-molded section 140 that surrounds and integrally seals the stacked body 130 consisting of the plurality of stacked battery cells 110 and the pair of end plates 120A and 120B arranged at both ends in the stacking direction.

[0161] Therefore, according to the cell stack 100 of the above embodiment, a plurality of battery cells 110, each composed of positive and negative electrodes 101, a diaphragm 103 disposed between the positive and negative electrodes 101, and a cell frame 1 on which the positive and negative electrodes 101 are arranged, are stacked, and a pair of end plates 120A and 120B are placed at both ends in the stacking direction to form a stacked body 130 which is then integrally sealed by a resin molded part 140 formed around it. This does not involve placing an electrical conductive member between the stacked cell frames 1 and end plates 120A and 120B and sealing the surfaces of the cell frames by welding through electrical current. Furthermore, sealing members such as O-rings and flat packings placed between the surfaces of the cell frames can be omitted, thus reducing the number of parts and man-hours and thus lowering costs.

[0162] In other words, since the resin-formed part 140 is formed around the laminate 130 by molding using liquid resin 140A, without the need for precise placement of sealing members such as O-rings and flat packings for sealing, or precise placement of conductive members for welding between cell frames 1, the cell frames and end plates of the laminate are tightly bonded around it, resulting in high sealing performance. Moreover, sealing the laminate 130 is effortless, making it possible to improve the efficiency of the assembly work of the cell stack 100, standardize quality, and increase productivity. Furthermore, sealing members such as O-rings and flat packings placed between the cell frames 1 can be omitted, and since the cell frames 1 are not welded together, the design freedom of the cell frames 1, including the design of the flow path for the electrolyte, can be increased, and the cell frames 1 can be made smaller. In addition, the diaphragm 103 placed between the cell frames 1 and between them and the end plates 120A and 120B does not come into contact with sealing members such as O-rings and flat packings, making it less likely to rupture. Therefore, a decrease in the charge / discharge rate due to mixing of positive and negative electrolytes caused by rupture of the diaphragm 103 is less likely to occur.

[0163] Furthermore, since sealing members such as O-rings or flat packings are not required between the cell frames 1, and the cell frames 1 are not sealed by welding or other means, the battery cell portion 110 of the laminated body 130 can be made thinner. As a result, the cell stack 100 can be made smaller, saving space. In addition, by making the battery cell portion 110 of the laminated body 130 thinner, electrical resistance can be reduced, improving battery efficiency and output.

[0164] Furthermore, the laminate 130 is covered and sealed entirely by the resin-formed portion 140. Since the entire resin-formed portion 140 surrounding the laminate 130 seals it, it restrains the laminate 130, and the resin-formed portion 140 can absorb changes in expansion and contraction due to changes in internal pressure and temperature of the electrolyte flowing inside the laminate 130. As a result, it is difficult to cause localized stress on the laminate 130, preventing damage to the constituent members, and furthermore, it is difficult to reduce the sealing performance by preventing misalignment of the cell frame 1 and end plates 120A and 120B. Thus, electrolyte leakage can be effectively prevented, and the battery life can be extended.

[0165] In addition, according to the cell stack 100 of this embodiment, the resin forming section 140 is provided in the resin through holes 151A, 151B, 151C, 151D provided in the frame 5 of the cell frame 1, and in the groove-shaped resin flow channels 152A, 152B, 152C, 152D that connect the resin through holes 151A, 151B, 151C, 151D to the outside of the frame 5 of the cell frame 1, as well as in the end plates 120A, 120B. Because it has resin-filled sections 140c and 140d that are filled into groove-shaped resin channels 252A, 252B, 252C, and 252D that connect the resin-filled holes 251A, 251B, 251C, and 251D to the outside of the end plates 120A and 120B, it is possible to further prevent misalignment and deformation of the cell frame 1 and the end plates 120A and 120B. Therefore, mixing and leakage of the electrolyte due to misalignment or deformation of the cell frame 1 or end plates 120A and 120B is less likely to occur. Consequently, battery performance is less likely to deteriorate.

[0166] Furthermore, in the cell stack 100 of the above embodiment, the resin-filled portions 140c, which are filled into the resin channels 152A, 152B, 152C, and 152D of the cell frame 1, are provided at two diagonal corners of the corner formed by the intersection of two sides of the outer edge of the cell frame 1 on one side of the cell frame 1, which is formed in a rectangular shape, and also at two other diagonal corners of the cell frame 1 on the other side of the cell frame 1. At each corner, the resin-filled portions 140d, which are filled into the resin through holes 151A, 151B, 151C, and 151D of the cell frame 1, are formed between the resin-filled portions 140d and the vertical sides E2 and E4 of the outer edge of the cell frame 1. Therefore, the liquid resin 140A can be efficiently and uniformly distributed around the outer circumference of the cell frame 1, resulting in good moldability. In particular, if the liquid resin 140A is flowed from the resin through holes 151A, 151B, 151C, and 151D toward the vertical sides E2 and E4 of the cell frame 1, the liquid resin 140A that merges with the horizontal sides E1 and E3 of the cell frame 1 is less likely to overflow and enter the electrolyte flow paths 31, 32, 41, and 42, thus avoiding any risk of impairing the flowability of the electrolyte.

[0167] Furthermore, in the cell stack 100 of the above embodiment, the resin-filled portions 140c filled in the resin channels 252A, 252B, 252C, and 252D of the end plates 120A and 120B are provided at two diagonal corners of the corner formed by the intersection of two sides of the outer edge of the end plates 120A and 120B on one side of the end plates 120A and 120B, which are formed in a rectangular shape overall, and at two other diagonal corners of the end plates 120A and 120B on the other side of the end plates 120A and 120B, and are formed between the resin-filled portions 140c filled in the resin through holes 251A, 251B, 251C, and 251D of the end plates 120A and 120B and the vertical edges E12 and 14 of the outer edge of the end plates 120A and 120B. Therefore, the liquid resin 140A could be efficiently and uniformly distributed around the outer circumference of the end plates 120A and 120B, resulting in good moldability. In particular, if the liquid resin 140A is flowed from the resin through holes 251A, 251B, 251C, and 251D toward the vertical edges E12 and E14 of the end plates 120A and 120B, the liquid resin 140A that merges at the horizontal edges E11 and E13 of the end plates 120A and 120B is less likely to overflow and enter the electrolyte flow paths 231, 232, 241, and 242, thus avoiding any impairment of the electrolyte's flowability.

[0168] Furthermore, in the cell stack 100 of the above embodiment, the resin forming portion 140 has resin engaging portions 140e filled in resin grooves 155A, 155B, 155C, 155D provided on the outer peripheral edge of the surface of the cell frame 1, separate from the resin channels 152A, 152B, 152C, 152D of the cell frame 1, and resin engaging portions 140e filled in resin grooves 255A, 255B, 255C, 255D provided on the outer peripheral edge of the surfaces of the end plates 120A, 120B. As a result, the cell frame 1 and the end plates 120A, 120B are firmly fixed and displacement can be prevented. Therefore, mixing and leakage of positive and negative electrolytes due to displacement or deformation of the cell frame 1 and the end plates 120A, 120B can be prevented.

[0169] In conventional cell stacks, a pair of metal end plates reinforced with a grid frame are placed at both ends of the laminated body 130 in the stacking direction, and the laminated body 130 is fastened and fixed by a fastening mechanism in which long bolts are connected between them and nuts are screwed onto the long bolts. In contrast, according to the cell frame 1 of this embodiment, the entire perimeter of the laminated body 130 is restrained and fixed by the resin molded part 140. Heavy and thick end plates made of metal and reinforced with a grid frame are unnecessary, and the frame bodies 125 of the pair of end plates 120A and 120B placed on both sides of the laminated body 130 can be made of the same resin as the frame body 5 of the cell frame 1, and the fastening mechanism described above is not required, making it possible to reduce weight and size.

[0170] Furthermore, since the resin molded portion 140 is formed by injection molding to enclose and restrain the laminate 130, the assembly of the cell stack 100 is very easy, reducing the number of assembly steps and parts, resulting in high productivity. The ability to bring the positive and negative electrodes 101 into close contact without the need for packing or other intermediaries also reduces electrical resistance, improving battery efficiency and output.

[0171] Furthermore, in this method, the laminate 130 is covered and sealed all at once by the resin-formed portion 140. The resin-formed portion 140 seals the space between the cell frames 1 by the close contact between the laminate 130 and the cell frames 1 and end plates 120A and 120B. This ensures a seal without applying high surface pressure as in the fastening mechanism described above, making the cell frames 1 less prone to deformation and preventing electrolyte leakage caused by deformation of the cell frames 1.

[0172] Furthermore, according to the cell stack 100 of the above embodiment, the resin-forming portion 140 has an annular resin-forming end portion 140a formed on its peripheral edge on the outer surface side of the end plates 120A and 120B, thereby improving the reliability of the sealing performance. Furthermore, according to the cell stack 100 of the above embodiment, the resin-forming end portion 140a of the resin-forming portion 140 has a resin-engaging portion 140 that engages with the end plates 120A and 120B on the outer surface side of the end plates 120A and 120B. Therefore, peeling between the resin-forming portion 140 and the end plates 120A and 120B is less likely to occur, and durability and sealing performance can be further improved.

[0173] In particular, according to the cell stack 100 of the above embodiment, the current collector 128 is inserted into the frame 125 of a pair of end plates 120A and 120B arranged at both ends in the stacking direction of the battery cells 110. Since the resin molded portion 140 is formed around the frame 125 in which the current collector 128 is inserted, rather than around the current collector 128, if the frame 125 is made of resin or the like, the adhesion with the resin molded portion 140 can be increased. Therefore, even a cell stack 100 that has a current collector 128 can have high sealing performance.

[0174] In addition, a resin-forming portion 140 is formed around the laminate 130 by filling it with liquid resin 140A. It is possible to form resin-forming openings 141A, 141B, 141C, and 141D integrally with the resin-forming portion 140, which serve as supply and drainage sections for supplying electrolyte to the manifolds 11 and 12 of the cell frame 1 or for draining electrolyte discharged from the manifolds 21 and 22 of the cell frame 1. Therefore, without the need to separately create supply and drainage plates or the like to serve as supply and drainage sections for supplying electrolyte to the manifolds 11 and 12 of the cell frame 1 or for draining electrolyte discharged from the manifolds 21 and 22 of the cell frame 1 and place them on the laminate 130, the resin-forming openings 141A, 141B, 141C, and 141D can be formed simultaneously with the molding of the resin-forming portion 140 that seals the laminate 130, on the end plate 120A and 120B sides located at both ends of the laminate 130 in the stacking direction. Therefore, the number of parts and man-hours required for the cell stack 100 can be reduced, leading to increased efficiency, improved productivity, lower costs, and lighter weight in the manufacturing of the cell stack 100.

[0175] In other words, according to the cell stack 100 of the above embodiment, the resin forming section 140 has cylindrical resin forming ports 141A, 141B, 141C, and 141D formed on the outer surface side of the end plates 120A and 120B for supplying and draining electrolyte. Therefore, the supply and drain ports for the electrolyte flowing through the cell stack 100 can be formed simultaneously with the sealing of the laminate 130, resulting in improved production efficiency and cost reduction.

[0176] In addition, according to the cell stack 100 of the above embodiment, the cell frame 1 has supply manifolds 11, 12 and drain manifolds 21, 22 through which the electrolyte flows, as well as electrolyte flow paths 31, 32, 41, 42. The resin-filled portions 140c filled in the resin flow paths 152A, 152B, 152C, 152D and the resin-filled portions 140d filled in the resin through holes 151A, 151B, 151C, 151D are located between the manifolds 11, 12, 21, 22 and the electrolyte flow paths 31, 32, 41, 42. Furthermore, the end plates 120A and 120B also have through-holes 211 and 212 for supplying electrolyte and through-holes 221 and 222 for draining electrolyte, as well as electrolyte flow paths 231, 232, 241 and 242. The resin-filled sections 140c, which are filled in the resin flow paths 252A, 252B, 252C and 252D, and the resin-filled sections 140d, which are filled in the resin through-holes 251A, 251B, 251C and 251D, are located between the through-holes 211, 212, 221 and 222 and the electrolyte flow paths 231, 232, 241 and 242.

[0177] Therefore, even if electrolyte spills out of the manifolds 11, 12, 13, and 14, the difference in height between the resin-filled sections 140c and 140d and the surface of the frame 5 of the cell frame 1 prevents it from mixing with electrolyte of the opposite polarity. Similarly, in the end plates 120A and 120B, even if electrolyte spills out of the through holes 211, 212, 221, and 222, the difference in height between the resin-filled sections 140c and 140d and the surface of the end plates 120A and 120B prevents it from mixing with electrolyte of the opposite polarity. Thus, a decrease in battery capacity can be prevented.

[0178] Furthermore, the above embodiment can also be considered as an invention of a redox flow battery having a cell stack 100 which is made up of multiple battery cells 110, each cell frame 1 consisting of positive and negative electrodes 101, a diaphragm 103 disposed between the positive and negative electrodes 101, an electrode arrangement portion 105 on which the positive and negative electrodes 101 are arranged, and a frame 5 provided around the electrode arrangement portion 105, and a pair of end plates 120A and 120B arranged at both ends in the stacking direction, wherein the cell stack 100 comprises a resin-formed portion 140 that surrounds and integrally seals the stacked body 130 consisting of the multiple stacked battery cells 110 and the pair of end plates 120A and 120B arranged at both ends in the stacking direction.

[0179] In the redox flow battery of the above embodiment, a plurality of battery cells 110 are stacked, each cell frame 1 consisting of positive and negative electrodes 101, a diaphragm 103 disposed between the positive and negative electrodes 101, an electrode arrangement section 105 on which the positive and negative electrodes 101 are arranged, and a frame 5 provided around the electrode arrangement section 105. A pair of end plates 120A and 120B are placed at both ends in the stacking direction to form a stacked body 130. The surrounding area of ​​the stacked cell frame 1 and the outer perimeter of the end plates 120A and 120B is integrally surrounded by a resin-molded section 140, thereby sealing the stacked body 130 as a whole.

[0180] Therefore, the outer perimeter of the stacked cell frame 1 and end plates 120A and 120B is sealed collectively with the resin-molded portion 140, and by omitting parts such as sealing members and conductive members for welding that are disposed between the surfaces of the cell frame, the number of parts and man-hours can be reduced. Thus, costs can be reduced.

[0181] By the way, the above embodiment includes an electrode arrangement section 105 on which positive and negative electrodes 101 are arranged, a frame 5 formed around the electrode arrangement section 105 and provided with manifolds 11, 12, 21, 22 through which the electrolyte flows and through the front and back surfaces, and resin through holes 151A, 151B, 151C, 151D filled with liquid resin 140A, and a section formed in the frame 5 that connects the electrode arrangement section 105 and the manifolds The invention can also be seen as a cell frame 1 comprising electrolyte flow channels 31, 41, 32, and 42 that connect the rings 11, 12, 21, and 22 and through which the electrolyte flows, and groove-shaped resin flow channels 152A, 152B, 152C, and 152D formed in the frame 5 that connect the resin through holes 151A, 151B, 151C, and 151D with the outside of the frame 5 and are filled with liquid resin 140A.

[0182] According to the cell frame 1 of the above embodiment, by filling and circulating liquid resin 140A through the resin through holes 151A, 151B, 151C, 151D formed through the front and back surfaces of the frame 5, and through groove-shaped resin channels 152A, 152B, 152C, 152D that connect the resin through holes 151A, 151B, 151C, 151D and the outside of the frame 5, it is possible to spread the liquid resin 140A around the outer perimeter of the cell frame 1. Thus, in a cell stack 100 formed by stacking multiple cell frames 1, it is possible to spread the liquid resin 140A around the outer perimeter of each cell frame 1, and to surround the entire outer perimeter of the stacked cell frames 1 with the resin forming portion 140, thereby sealing the stacked cell frames 1 together. Therefore, in the cell stack 100, parts such as sealing members and conductive members for welding that are arranged between one surface of the cell frame can be omitted, thus reducing the number of parts and man-hours, and thus lowering costs.

[0183] Furthermore, according to the cell frame 1 of the above embodiment, the resin channels 152A, 152B, 152C, and 152D are provided at two opposing corners of the frame 5 on each of the front and back surfaces of the frame 5, which is formed in a substantially rectangular shape overall. Since they extend from the resin through holes 151A, 151B, 151C, and 151D toward the vertical sides of the cell frame 1, the liquid resin 140A can be efficiently and uniformly distributed around the outer circumference of the cell frame 1. Therefore, the moldability of sealing the laminated body 130 of the cell stack 100, which is formed by stacking cell frames 1, with the resin forming section 140 can be improved. In particular, if the liquid resin 140A is flowed from the resin through holes 151A, 151B, 151C, and 151D toward the vertical sides E2 and E4 of the cell frame 1, the liquid resin 140A that merges with the horizontal sides E1 and E3 of the cell frame 1 is less likely to overflow and enter the electrolyte flow paths 31, 32, 41, and 42, thus avoiding any risk of impairing the flowability of the electrolyte.

[0184] According to the cell frame 1 of the above embodiment, the resin through holes 151A, 151B, 151C, 151D and the resin flow paths 152A, 152B, 152C, 152D are located between the manifolds 11, 12, 21, 22 and the electrolyte flow paths 31, 32, 41, 42, and the resin through holes 151A, 151B, 151C, 151D and the resin flow paths 152A, 152B, 152C, 152D When liquid resin 140A is filled, resin-filled sections 140c and 140d are formed, creating a step between the resin-filled section 140c and the surface of the frame 5. Therefore, even if electrolyte spills out of the manifolds 11, 12, 21, and 22, the step between the resin-filled sections 140c and 140d and the surface of the frame 5 prevents the spilled electrolyte from mixing with electrolyte of the opposite polarity. Thus, a decrease in battery efficiency can be prevented.

[0185] Furthermore, according to the above embodiment of the cell frame 1, the resin-forming portion 140 has resin engaging portions 140e filled in resin grooves 155A, 155B, 155C, 155D provided on the outer peripheral edge of the surface of the cell frame 1, separate from the resin channels 152A, 152B, 152C, 152D of the cell frame 1. This firmly fixes the cell frame 1 and prevents misalignment. Therefore, mixing and leakage of positive and negative electrolytes due to misalignment or deformation of the cell frame 1 can be prevented.

[0186] According to the cell frame 1 of the above embodiment, a rib 115 is formed in the electrolyte flow paths 31, 41, 32, 42 on the connection side with the manifolds 11, 12, 21, 22, thereby reinforcing the area around the manifolds 11, 12, 21, 22, and preventing deformation of the cell frame 1 due to the internal pressure of the electrolyte flowing through the manifolds 11, 12, 21, 22 and the internal pressure of the liquid resin 140A flowing through the resin through holes 151A, 151B, 151C, 151D and the resin flow paths 152A, 152B, 152C, 152D. Furthermore, the internal pressure of the electrolyte flowing through manifolds 11, 12, 21, 22 and the internal pressure of the liquid resin 140A flowing through resin through-holes 151A, 151B, 151C, 151D and resin flow paths 152A, 152B, 152C, 152D prevent adjacent diaphragms 103 from falling into flow paths 31, 32, 41, 42 and being damaged. Thus, the durability of the cell stack 100 can be improved. Moreover, it is possible to prevent displacement of the diaphragms 103 by holding down the diaphragms 103 positioned between adjacent cell frames 1 in the cell stack 100. Thus, a decrease in charge / discharge rate due to mixing of positive and negative electrolytes can be prevented.

[0187] Furthermore, the above embodiment is an end plate 120A, 120B arranged at the end of the stacking direction of the battery cell 110 of a cell stack 100 which is made up of multiple battery cells 110 each consisting of positive and negative electrodes 101, a diaphragm 103 disposed between the positive and negative electrodes 101, and a cell frame 1 on which the positive and negative electrodes 101 are arranged, and electrolyte through-holes 211, 212, 221, 222 that penetrate the front and back surfaces and through which the electrolyte flows, and The invention can also be understood as an invention of resin through holes 251A, 251B, 251C, 251D into which a resin-filled portion 140c is formed when liquid resin 140A is filled, and end plates 120A, 120B into which groove-shaped resin channels 252A, 252B, 252C, 252D are formed that connect the resin through holes 251A, 251B, 251C, 251D to the outside of the end plate 120 and into which liquid resin 140A is filled.

[0188] In the end plates 120A and 120B of the above embodiment, resin through-holes 251A, 251B, 251C, 251D and resin channels 252A, 252B, 252C, 252D are formed that penetrate the front and back surfaces and are filled with liquid resin 140A. By filling and circulating the liquid resin 140A through these holes, it is possible to spread the liquid resin 140A around the outer perimeter of the end plates 120A and 120B. Thus, in a cell stack 100 in which multiple cell frames 1 are stacked and a pair of end plates 120A and 120B are placed at both ends in the stacking direction, the liquid resin 140A can spread around the outer perimeter of the end plates 120A and 120B together with the cell frames 1, and the entire outer perimeter of the stacked cell frames 1 and end plates 120A and 120B can be surrounded by the resin forming portion 140, thereby sealing the cell frames 1 and end plates 120A and 120B together. Therefore, in the cell stack 100, parts such as sealing members and conductive members for welding that are arranged between the cell frame 1 and the end plates 120A and 120B can be omitted, thus reducing the number of parts and man-hours, and lowering costs.

[0189] Furthermore, according to the end plates 120A and 120B of the above embodiment, an annular recess 126 is formed on the peripheral edge of one side of the front and back surfaces, where liquid resin 140A is filled. Therefore, by positioning the surface with the annular recess 126 on the outer side of the cell stack 100 during assembly, the liquid resin 140A that flows from the outer circumference of the end plates 120A and 120B of the cell stack 100 to the outer side will fill the annular recess 126. As a result, the engagement relationship between the resin engagement portion 140b formed by the liquid resin 140A filling the annular recess 126 and the recess 126 of the end plates 120A and 120B makes it difficult for the resin forming portion 140 to peel off from the end plates 120A and 120B. Therefore, durability and sealing performance can be improved.

[0190] Furthermore, according to the end plates 120A and 120B of the above embodiment, the resin channels 252A, 252B, 252C, and 252D are provided at two diagonal corners on each of the front and back surfaces, which are formed in a rectangular shape, and extend from the resin through holes 252A, 252B, 252C, and 252D toward the vertical outer edge of the end plates 120A and 120B, respectively. This allows the liquid resin 140A to be efficiently and uniformly distributed around the outer circumference of the end plates 120A and 120B. Therefore, the moldability of sealing the laminated body 130 of the cell stack 100, which is formed by stacking the cell frame 1 and the end plates 120A and 120B, with the resin forming portion 140 can be improved. In particular, if the liquid resin 140A is flowed from the resin through-holes 251A, 251B, 251C, and 251D toward the vertical edges E12 and E4 of the end plates 120A and 120B, the liquid resin 140A that merges at the horizontal edges E12 and E13 of the end plates 120A and 120B is less likely to overflow and enter the electrolyte flow paths 231, 232, 241, and 242, thus avoiding any risk of impairing the flowability of the electrolyte.

[0191] According to the end plates 120A and 120B of the above embodiment, the resin through holes 251A, 251B, 251C, 251D and resin flow channels 252A, 252B, 252C, 252D are located between the through holes 211, 212, 221, 222 and the electrolyte flow channels 231, 232, 241, 242. A step is formed between the resin-filled portions 140c, 14d, which are formed by filling the resin through holes 251A, 251B, 251C, 251D and resin flow channels 252A, 252B, 252C, 252D with liquid resin 140A, and the surfaces of the end plates 120A and 120B. Therefore, even if electrolyte spills out of the electrolyte through-holes 211, 212, 221, and 222, the step difference between the resin-filled section 140c and the surfaces of the end plates 120A and 120B prevents the electrolyte from mixing with electrolyte of the opposite polarity. Thus, a decrease in battery capacity can be prevented.

[0192] Furthermore, according to the end plates 120A and 120B of the above embodiment, the resin-forming portion 140 has a resin engaging portion 140e filled in resin grooves 255A, 155B, 255C, and 255D provided on the outer peripheral edge of the surface of the end plates 120A and 120B, separate from the resin channels 252A, 252B, 252C, and 252D of the end plates 120A and 120B. This firmly fixes the end plates 120A and 120B and the cell frame 1, preventing misalignment. Therefore, mixing and leakage of positive and negative electrolytes due to misalignment or deformation of the end plates 120A and 120B or the cell frame 1 can be prevented.

[0193] According to the end plates 120A and 120B of the above embodiment, since they consist of a current collector 128 and a frame 125 into which the current collector is inserted, the resin-formed portion 140 is formed around the frame 125 into which the current collector 129 is inserted, rather than around the current collector 128. If the frame 125 is made of resin or the like, the adhesion with the resin-formed portion 140 formed around its outer circumference can be increased. Therefore, even a cell stack 100 on which the current collector 128 is arranged will have high sealing performance. Furthermore, since the end plates 120A and 120B are equipped with current-carrying terminals 182 that are integrally provided with the current collectors 128 and protrude from the outer surface of the end plates 120A and 120B, electrical connection to an external power source can be easily made.

[0194] According to the end plates 120A and 120B of the above embodiment, the frame 125 has an opening 125B in the center of one side through which the current collector 128 is exposed, and has electrolyte flow paths 231, 232, 241, and 242 through which the electrolyte flows, connecting the electrolyte through-holes 211, 212, 221, and 222 with the opening 125B, thereby enabling the electrolyte to undergo a battery reaction on the current collector 125. As a result, it is possible to increase output power in a space-saving manner and improve battery efficiency.

[0195] According to the end plates 120A and 120B of the above embodiment, since ribs 115 are formed on the side of the electrolyte flow paths 231, 232, 241, and 242 that connect to the electrolyte through-holes 211, 212, 221, and 222, the area around the electrolyte through-holes 211, 212, 221, and 222 is reinforced, preventing deformation of the end plates 120A and 120B due to the internal pressure of the electrolyte flowing through the electrolyte through-holes 211, 212, 221, and 222, as well as the internal pressure of the liquid resin 140 flowing through the resin through-holes 251A, 251B, 251C, and 251D and the resin flow paths 252A, 252B, 252C, and 252D. Furthermore, it is possible to prevent displacement of the diaphragm 130, which is positioned between adjacent cell frames 1 in the cell stack 100, by holding it in place. Furthermore, the internal pressure of the electrolyte flowing through the electrolyte through-holes 211, 212, 221, and 222, as well as the internal pressure of the liquid resin 140 flowing through the resin through-holes 251A, 251B, 251C, 251D and the resin flow paths 252A, 252B, 252C, 252D, can prevent adjacent diaphragms from falling into the flow paths 231, 232, 241, and 242. In addition, it can prevent foreign matter from reaching the electrode 101. Therefore, the durability of the Cell Stack 100 can be improved.

[0196] According to the end plates 120A and 120B of the above embodiment, the frame 125 and current collector 128 have terminal openings 128A and 125A formed on one side thereof into which a rod-shaped current terminal 182 is inserted. Therefore, when configuring the cell stack 100, the rod-shaped current terminal 182 can be easily connected to the current collector 128 by inserting it into the opening 128A or 125A and screwing a nut 184 or the like onto it and tightening it. Thus, electrical connection with an external power supply can be easily made.

[0197] The cell stack 100 of the above embodiment comprises a battery cell 110 composed of a positive electrode 101 and a negative electrode 102, a diaphragm 103 disposed between the positive electrode 101 and the negative electrode 102, an electrode arrangement section 105 on both sides where the positive electrode 101 and the negative electrode 103 are arranged, and a frame 5 provided around the electrode arrangement section 105; a pair of end plates 120A, 120B disposed at both ends in the stacking direction where multiple battery cells 110 are stacked; and the end plates 120A, 120B and adjacent to them The device comprises a current collector 128 disposed between the cell frame 1 and the cell frame 1, a current-carrying terminal 182 integrally provided on the current collector 128 and passing through the end plates 120A and 120B, a nut 184 as a fastener that fits into the current-carrying terminal 182 passing through the end plates 120A and 120B and fastens and fixes the pair of end plates 120A and 120B, and a resin-molded part 140 that surrounds and integrally seals the laminate 130 consisting of multiple stacked battery cells 1, current collectors 128 and a pair of end plates 120A and 120B.

[0198] In particular, a nut 184 is fitted to the current-carrying terminal 182, which is integrally formed with the current collector 128 and penetrates the end plates 120A and 120B, and the pair of cell frames 1 are tightened and fixed together by the nut 184. This makes it less likely for the cell frames 1 to shift position or deform, and provides high reliability in sealing.

[0199] Furthermore, the above embodiment involves stacking multiple battery cells 110, each cell stack 100 and each end plate 120A, 120B of a stack 130, each cell stack 100 and each end plate 120A, 120B of the stack, which are arranged at both ends in the stacking direction. This invention can also be seen as a method for manufacturing a cell stack 100, comprising an assembly step of assembling a laminate 130 by inserting a shaft 311 through through holes 211, 212, 221, 222 formed through the front and back surfaces of the cell stack and through holes for electrolyte flow during charging and discharging, and manifolds 11, 12, 21, 22, as well as a resin forming step of forming a resin forming part 115 around the laminate 130, and a removal step of removing the shaft 311 from the laminate 130.

[0200] According to the manufacturing method of the cell stack 100 of the above embodiment, a cell stack 100 is formed in which the laminate 130 is surrounded and sealed by a resin forming portion 140. The resin forming portion 140 integrally surrounds the periphery of the laminate 130, that is, the outer periphery of the laminated cell frames 1 and end plates 120A and 120B, so that the cell frames 1 of the laminate 130 and the cell frames 1 and end plates 120A and 120B are tightly bonded together and sealed as a whole. Therefore, by omitting parts such as sealing members and conductive members for welding that are disposed between the faces of the cell frames 1, the number of parts and man-hours can be reduced. Thus, costs can be reduced.

[0201] In particular, the through-holes 211, 212, 221, 222 and manifolds 11, 12, 21, 222 formed in the end plates 120A, 120B and cell frame 1, which serve as through-holes for the electrolyte during charging and discharging, are utilized to insert the shaft 313 into these holes to assemble the cell frame 1 and end plates 120A, 120B. This allows for precise positioning and assembly of the cell frame 1 and end plates 120A, 120B with a small number of parts and labor, resulting in high productivity and reliable sealing performance.

[0202] Furthermore, in the manufacturing method of the cell stack 100 described above, in the resin forming step, liquid resin 140A for forming the resin forming portion 140 is injected through resin through holes 251A, 251B, 251C, and 251D formed in the end plates 120A and 120B through their front and back surfaces in the liquid resin filling step, and resin channels are formed to connect the resin through holes 251A, 251B, 251C, and 251D in the end plates 120A and 120B with the outside of the end plates 120A and 120B. Liquid resin 140A is circulated through 152A, 152B, 152C, and 152D, and liquid resin 140A is also circulated through resin through holes 151A, 151B, 151C, and 151D formed in the cell frame 1 that penetrate the front and back surfaces, and through resin channels 152A, 152B, 152C, and 152D that connect the cell frame 1 to the outside, thereby spreading the liquid resin 140A around the laminate 130. During the cooling process, the liquid resin 140A is cooled and solidified to form the resin-formed portion 140. By circulating liquid resin 140A inside the cell frame 1 and end plates 120A, 120B and spreading it around their outer periphery, resin filling portions 140c, 140d of the resin forming portion 140 are also formed in the resin through holes 251A, 251B, 251C, 251D and resin through holes 151A, 151B, 151C, 151D, as well as the resin channels 152A, 152B, 152C, 152D and resin channels 252A, 252B, 252C, 252D formed inside the cell frame 1 and end plates 120A, 120B. As a result, the laminate 130 is more firmly restrained, preventing misalignment and deformation of the cell frame 1 and end plates 120A, 120B after assembly. Therefore, mixing and leakage of the electrolyte due to misalignment or deformation of the cell frame 1 can be prevented, thus preventing a decrease in battery efficiency and improving sealing performance.

[0203] In the above embodiment, the groove-shaped resin channels 152A, 152B, 152C, and 152D, which are formed to connect the manifolds 11, 12, 21, 22 with two adjacent sides of the outer shape of the cell frame 1, extend in a substantially curved shape from the resin through holes 151A, 151B, 151C, and 151D toward the vertical sides E2 and E4 of the cell frame 1. However, when implementing the present invention, the shape of the resin channels 152A, 152B, 152C, and 152D is not limited to the above-described shape, as long as the liquid resin 140A from the resin through holes 151A, 151B, 151C, and 151D can be guided toward the outer circumference of the cell frame 1. They may also extend in a substantially straight line, or be formed in a substantially L-shape as shown in Figure 14.

[0204] In the modified cell frame 1 shown in Figure 14, the cell frame 1 is formed in a roughly rectangular shape with four sides having two sides of equal length. On each front and back surface of the cell frame 1, groove-shaped resin channels 152A, 152B, 152C, and 152D connect the two adjacent sides at at least two opposing corners formed by the intersection of two adjacent sides, forming a roughly L-shape.

[0205] More specifically, as shown in Figure 14(a), the resin channel 152B, which is formed between the negative electrode side liquid supply manifold 12 and the positive electrode side introduction channel 31, is located at the corner formed by the intersection of two adjacent sides E1 and E2 on the outer edge of the cell frame 1. The channel is formed in a substantially L-shape to connect the negative electrode side liquid supply manifold 12 with the two adjacent sides E1 and E2, and is also formed to intersect each side of the two adjacent sides E1 and E2 at substantially right angles. The resin channel 152D, formed between the negative electrode side drainage manifold 22 and the positive electrode side discharge channel 41, is located at the corner formed by the intersection of two adjacent sides E3 and E4 on the outer edge of the cell frame 1. The resin channel 152D is formed in a substantially L-shape so as to connect the resin through-hole 151D with the two adjacent sides E3 and E4, and is also formed to intersect each side of the two adjacent sides E3 and E4 at substantially right angles.

[0206] As shown in Figure 14(b), the resin channel 152A, which is formed between the positive electrode side fluid supply manifold 11 and the negative electrode side introduction channel 32, is located at the corner formed by the intersection of two adjacent sides E1 and E4 on the outer edge of the cell frame 1. The resin channel 152A is formed in a substantially L-shape so as to connect the resin through hole 151A with the two adjacent sides E1 and E4, and is also formed to intersect each side of the two adjacent sides E1 and E4 at substantially right angles. The resin channel 152C, formed between the positive electrode side drainage manifold 21 and the negative electrode side discharge channel 42, is located at the corner formed by the intersection of two adjacent sides E2 and E3 on the outer edge of the cell frame 1. The resin channel 152C is formed in a substantially L-shape to connect the resin through-hole 151C with the two adjacent sides E2 and E3, and is also formed to intersect each side of the two adjacent sides E2 and E3 at substantially right angles.

[0207] As a result, the liquid resin 140A flowing through the resin through-hole 151A formed in the cell frame 1 of Modified Example 1 branches off in the resin channel 152A and flows into the sides E1 and E4 of the outer edge of the cell frame 1, the liquid resin 140A flowing through the resin through-hole 151B branches off in the resin channel 152B and flows into the sides E1 and E2, the liquid resin 140A flowing through the resin through-hole 151C branches off in the resin channel 152C and flows into the sides E2 and E3, and the liquid resin 140A flowing through the resin through-hole 151D branches off in the resin channel 152D and flows into the sides E3 and E4. Then, on edge E1 of cell frame 1, the liquid resin 140A that flowed in through the resin through hole 151A and through the resin channel 152A merges with the liquid resin 140A that flowed in through the resin through hole 151B and through the resin channel 152B. On edge E2 of cell frame 1, the liquid resin 140A that flowed in through the resin through hole 151B and through the resin channel 152B merges with the liquid resin 140A that flowed in through the resin through hole 151C and through the resin channel 152C. On side E3 of cell frame 1, the liquid resin 140A that flowed in through the resin through hole 151C and through the resin channel 152C merges with the liquid resin 140A that flowed in through the resin through hole 151D and through the resin channel 152D. On side E4 of cell frame 1, the liquid resin 140A that flowed in through the resin through hole 151D and through the resin channel 152D merges with the liquid resin 140A that flowed in through the resin through hole 151A and through the resin channel 152A. As a result, the liquid resin 140A spreads throughout the entire perimeter of the four sides E1, E2, E3, and E4 of the outer edge face of each cell frame 1, and as it cools and solidifies, a resin forming portion 140 is formed around the outer perimeter of each cell frame 1. In addition, a resin forming portion 140c is formed in a roughly L-shape.

[0208] Therefore, in this case, since the resin channels 152A, 152B, 152C, and 152D of the cell frame 1 connect two adjacent sides of the outer shape of the cell frame 1, the liquid resin 140A can be more efficiently and uniformly distributed to the surrounding sides E1, E2, E3, and E4 of the cell frame 1. Furthermore, since the manifolds 11, 2, 21, and 22 are surrounded by the roughly L-shaped resin molding portion 140c and the outer edge of the cell frame 1, even if electrolyte spills out of the manifolds 11, 12, 21, and 22, the step difference between the roughly L-shaped resin molding portion 140c and the surface of the cell frame 1 effectively prevents it from mixing with electrolyte of the opposite polarity to the positive and negative polarity of the spilled electrolyte. The same applies to the resin channels 252A, 252B, 252C, and 252D of the end plates 120A and 120B.

[0209] Furthermore, in the above embodiment, the inlet channels 31, 32, 231, 232 and the discharge channels 41, 42, 241, 242, and the resin channels 152A, 152B, 152C, 152D, 252A, 252B, 252C, 252D have a substantially concave cross-section. However, the channel walls and groove bottoms forming them are not limited to a planar (straight) shape, but may be curved (curved), and opposing channel walls may be parallel, or they may be tapered. The corners between the channel walls and the groove bottoms are not limited to a substantially right angle, but may be formed in an R shape. Furthermore, while the through-holes for resin flow and electrolyte flow are formed in a circular shape in the above embodiment, the present invention is not limited to a circular shape.

[0210] Furthermore, in the above embodiment, manifolds 11, 2, 21, and 22 are formed at the four corners of the cell frame 1. As a result, the resin channels 152A, 152B, 152C, and 152D that connect the resin through holes 151A, 151B, 151C, and 151D provided near the manifolds 11, 2, 21, and 22 to the outside of the cell frame 1 are provided at two locations on one diagonal corner of one side of the cell frame 1 and at two locations on the other diagonal corner of the other side. However, when implementing the present invention, there may be one or more resin channels on each surface of the cell frame 1, or four or more may be formed on each surface. The number of resin channels may differ on the front and back surfaces, they may be provided in the same position on the front and back surfaces, or they may be provided in different positions. The same applies to the end plates 120A and 120B.

[0211] Furthermore, in the above embodiment, the multiple battery cells 110 were described as being connected to each other so that the electrolyte flows through each battery cell 110 in parallel. However, when implementing the present invention, the connection configuration of the multiple electrical cells 110 is not limited to this, and for example, they may be connected to each other so that the electrolyte flows through the multiple battery cells 110 in series. Furthermore, although the cell stack of the present invention was described in the above explanation using an example of application to a redox flow battery, the present invention is not limited to redox flow batteries and can be applied to other storage batteries and fuel cells.

[0212] Furthermore, when implementing the present invention, the configuration, materials, manufacturing process, etc., of the cell frame 1, cell stack 100, and other parts of the redox flow battery are not limited to those described in the above embodiments. Also, the numerical values ​​given in the above embodiments are appropriate values ​​suitable for implementation, and slightly changing these values ​​does not negate implementation. [Explanation of Symbols]

[0213] 1 cell frame 5 Frame 11. Manifold for supplying fluid to the positive electrode 12. Manifold for negative electrode fluid supply 21 Manifold for draining the positive electrode side 22. Manifold for draining the negative electrode 31 Positive electrode side introduction channel 32 Negative electrode side introduction channel 41 Positive electrode side discharge channel 42 Negative electrode side discharge channel 100-cell stack 101 Electrode 103 Diaphragm 110 battery cells 126 recess 128 Current collector 130 Laminate 140 Resin forming section 140A Liquid Resin 141A, 141B, 141C, 141D Resin forming opening 140a Resin forming end 140b Resin molded engagement part 140c Resin filling part 140d Resin filling part 151A, 151B, 151C, 151D Through hole for resin 152A, 152B, 152C, 152D Resin channel 182 Conductive terminals 211, 212, 221, 222 through holes 251A, 251B, 251C, 251D Through hole for resin 252A, 252B, 252C, 252D Resin channel 311 axis

Claims

1. A plurality of battery cells, each comprising positive and negative electrodes, a diaphragm placed between the positive and negative electrodes, and a cell frame on which the positive and negative electrodes are arranged, A pair of end plates are arranged at both ends in the stacking direction of the stacked battery cells, A resin-formed portion encloses and integrally seals the laminate, which consists of the multiple stacked battery cells and a pair of end plates arranged at both ends in the stacking direction. It is equipped with, The cell stack is characterized in that the resin forming portion has resin through holes provided in the cell frame and groove-shaped resin channels provided on the surface of the cell frame that connect the resin through holes to the outside of the cell frame, and a resin filling portion filled in resin through holes provided in the end plate and groove-shaped resin channels provided on the surface of the end plate that connect the resin through holes to the outside of the end plate.

2. The cell frame has a manifold through which the electrolyte flows and an electrolyte flow path, The resin-filled portion, which is filled into the resin channel of the cell frame, is located between the manifold and the electrolyte channel of the cell frame. Furthermore, the cell stack according to claim 1, wherein the end plate has through holes and electrolyte channels through which the electrolyte flows, and the resin-filled portion filled in the resin channel of the end plate is located between the through holes and the electrolyte channel of the end plate.

3. The cell stack according to claim 1, characterized in that the resin forming portion has a cylindrical resin forming port formed on the outer surface side of the end plate through which the electrolyte is supplied and drained.

4. The cell stack according to claim 1, characterized in that the resin-forming portion has an annular resin-forming end formed on the peripheral edge on the outer surface side of the end plate.

5. The cell stack according to claim 4, characterized in that the resin-formed end of the resin-formed portion has a resin-engaging portion that engages with the end plate on the outer surface side of the end plate.

6. A redox flow battery having a cell stack comprising a plurality of battery cells, each cell being composed of positive and negative electrodes, a diaphragm placed between the positive and negative electrodes, and a cell frame on which the positive and negative electrodes are arranged, with a pair of end plates placed at both ends in the stacking direction, The cell stack comprises a resin-molded portion that encloses and integrally seals the stack, which consists of the multiple stacked battery cells and a pair of end plates arranged at both ends in the stacking direction. A redox flow battery characterized in that the resin forming portion has resin through holes provided in the cell frame and groove-shaped resin channels provided on the surface of the cell frame that connect the resin through holes to the outside of the cell frame, and a resin filling portion filled in resin through holes provided in the end plate and groove-shaped resin channels provided on the surface of the end plate that connect the resin through holes to the outside of the end plate.

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