Power storage module and power storage device

Abstract

Provided are a power storage module and a power storage device. The power storage module includes: a main body portion provided with a plurality of communication paths; and a liquid injection part having a plurality of liquid injection ports attached to one side surface of the main body part and communicating with each of the communication paths. Among the plurality of liquid injection frames provided in the main body part, there are a first liquid injection frame in which a part of the liquid injection frame protrudes from the main body part at least on one side in the first direction, and a second liquid injection frame in which a part of the liquid injection frame protrudes from the main body part at least on the other side in the first direction. The protruding amount of the first liquid injection frame body is larger than the protruding amount of the second liquid injection frame body with respect to the protruding amount of the part of the liquid injection frame body protruding from the main body part on one side in the first direction, and the protruding amount of the part of the liquid injection frame body protruding from the main body part on the other side in the first direction is smaller than the protruding amount of the second liquid injection frame body. The protruding amount of the second liquid injection frame body is larger than the protruding amount of the first liquid injection frame body.

Description

Technical Field

[0001] One aspect of the present invention relates to a power storage module and a power storage device. Background Art

[0002] A power storage module having a stacked body with stacked battery cells is known, wherein the battery cell includes an electrode plate, a positive electrode provided on one surface of the electrode plate, and a negative electrode provided on the other surface of the electrode plate (for example, Patent Document 1). In such a power storage module, the stacked body is surrounded by a resin seal (sealing portion). An injection port (a communication path that connects the inside of the battery cell with the outside) for injecting electrolyte into the inside of each battery cell of the power storage module is formed on the side surface of the resin seal along the stacking direction of the stacked body (the main body of the power storage module).

[0003] Patent Document 1: Japanese Patent Application Publication No. 2012-234823

[0004] It is preferred that the injection of electrolyte into each battery cell is carried out in a state where the injection port provided on the side surface of the main body of the storage module and the accessories for injecting electrolyte are sealed (maintaining airtightness). Therefore, it can be considered to form a frame functioning as a sealing surface around the injection port of each storage module so as to ensure airtightness between the injection port and the accessories installed on the injection port. At this time, when observed from the side surface of the storage module, the frame formed in a manner of surrounding the injection port connected to the outermost unit in the storage module protrudes from the main body of the storage module in the stacking direction. Therefore, in the storage module, the stacking direction dimension around the injection port is larger than the stacking direction dimension of other parts. For a storage device composed of a plurality of such storage modules with different local thicknesses, adjacent modules in the stacking direction are arranged in a state separated by a predetermined interval in a non-contact manner, so that the size of the storage device in the stacking direction becomes larger. Summary of the invention

[0005] Therefore, an object of one aspect of the present invention is to provide a power storage module and a power storage device that can suppress an increase in the size in the stacking direction when assembled as a power storage device even when a frame is provided around a liquid injection port for injecting an electrolyte.

[0006] The storage module involved in one aspect of the present invention is a storage module for a stacked storage device, and comprises: an electrode stack having bipolar electrodes stacked along a first direction, the bipolar electrode having a positive electrode formed on a first surface of a collector and a negative electrode formed on a second surface opposite to the first surface; and a sealing portion, which forms an internal space between adjacent collectors in the first direction and seals the internal space, the sealing portion comprising: a main body, which is a cylindrical body formed in a rectangular frame shape so as to surround the electrode stack when viewed from the first direction, and a plurality of communication paths respectively connected to the plurality of internal spaces are provided on one side surface of the cylindrical body; and a liquid injection portion, which has a plurality of liquid injection ports, the plurality of liquid injection ports being installed on a side surface of the main body and respectively connected to the communication paths, the liquid injection portion having a plurality of liquid injection frames, the liquid injection frames The body makes the ends of multiple connecting paths arranged along the first direction independent of each other and surrounds the ends of the multiple connecting paths to form an injection port, and the multiple injection frames are arranged on a side surface of the main body along a second direction orthogonal to the first direction. Among the multiple injection frames arranged along the second direction, there are: a first injection frame that makes a part of the injection frame protrude from the main body on at least one side of the first direction and a second injection frame that makes a part of the injection frame protrude from the above-mentioned main body on at least the other side of the first direction. Regarding the protrusion amount of the part of the injection frame protruding from the main body on one side of the first direction, the protrusion amount of the first injection frame is larger than the protrusion amount of the second injection frame, and regarding the protrusion amount of the part of the injection frame protruding from the main body on the other side of the first direction, the protrusion amount of the second injection frame is larger than the protrusion amount of the first injection frame.

[0007] The power storage device is formed by stacking a plurality of power storage modules. In the power storage module involved in one aspect of the present invention, a liquid injection frame forming a liquid injection portion for injecting electrolyte is made to protrude from the main body in a first direction as the stacking direction, but the first liquid injection frame is made larger than the second liquid injection frame in terms of the amount of protrusion of a part of the liquid injection frame from the main body on one side in the first direction, and the second liquid injection frame is made larger than the first liquid injection frame in terms of the amount of protrusion of a part of the liquid injection frame from the main body on the other side in the first direction. Thus, it is possible to eliminate the situation where the parts that protrude significantly from the main body face each other in the first direction, and it is possible to suppress the enlargement of the stacking direction dimension when assembling the power storage device.

[0008] Alternatively, in the battery module according to one aspect of the present invention, for the first liquid injection frame, a portion of the liquid injection frame protrudes from the main body only on one side in the first direction, and for the second liquid injection frame, a portion of the liquid injection frame protrudes from the main body only on the other side in the first direction.

[0009] In the power storage module according to one aspect of the present invention, a plurality of first liquid injection frames and a plurality of second liquid injection frames may be provided, the first liquid injection frames may be continuously arranged in the second direction, and the second liquid injection frames may be continuously arranged in the second direction.

[0010] In the power storage module according to one aspect of the present invention, a plurality of each of the first liquid injection frame and the second liquid injection frame may be provided, and the first liquid injection frame and the second liquid injection frame may be alternately arranged in the second direction.

[0011] In the power storage module according to one aspect of the present invention, the liquid injection portion may further include an overhanging portion connected to the main body portion and covering parts of both end surfaces of the electrode stack in the first direction.

[0012] In the power storage module according to one aspect of the present invention, a laminate film covering the liquid injection port may be attached to the liquid injection frame.

[0013] Alternatively, in an energy storage module according to one aspect of the present invention, when, in a stack, the positive electrode at one end of the stack in the first direction is set as a terminal positive electrode, and the negative electrode at the other end of the stack in the first direction is set as a terminal negative electrode, an exposed surface exposed to the outside is formed on one surface of a current collector in the terminal positive electrode where no positive electrode is formed and on one surface of a current collector in the terminal negative electrode where no negative electrode is formed.

[0014] In an electric storage device according to one aspect of the present invention, a plurality of the above-mentioned electric storage modules and a conductive conductive plate may be provided, and the electric storage modules may be stacked in the first direction via a second conductive plate in contact with the exposed surface.

[0015] It may also be that in the power storage device involved in one aspect of the present invention, when the power storage modules are stacked in a manner such that one side is vertically upward and the other side is vertically downward and the first liquid injection frame is arranged along the vertical direction and the second liquid injection frame is arranged along the vertical direction, when observing the adjacent power storage modules in the vertical direction, the lower end of the second liquid injection frame of one power storage module is located below the upper end of the first liquid injection frame of another power storage module.

[0016] According to one aspect of the present invention, even when a frame is provided around the injection port for injecting an electrolyte solution, it is possible to suppress an increase in the size in the stacking direction when assembled as an electricity storage device. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a side view of the power storage module according to one embodiment as viewed from the X-axis direction.

[0018] Figure 2This is a plan view of the power storage module according to one embodiment when the power storage module is viewed from above in the Z-axis direction.

[0019] Figure 3 is from Figure 1 and Figure 2 A cross-sectional view taken along line III-III is shown.

[0020] Figure 4 When viewed from the X-axis direction, the stack Figure 1 A side view of the power storage module as seen from the power storage device.

[0021] Figure 5 is from Figure 4 A schematic cross-sectional structure diagram of a power storage device as viewed along line VV is shown.

[0022] Figure 6 This is a side view of the power storage module according to the modification example as seen from the X-axis direction. DETAILED DESCRIPTION

[0023] Hereinafter, one embodiment according to one aspect of the present invention will be described in detail with reference to the accompanying drawings. In the description of the drawings, the same or similar elements are denoted by the same reference numerals, and repeated descriptions are omitted. Figure 1 to Figure 6 An XYZ orthogonal coordinate system that is orthogonal to each other is shown. The X-axis direction, the Y-axis direction (second direction), and the Z-axis direction (first direction) are orthogonal to each other.

[0024] Figure 1 to Figure 3 The power storage module 1 shown includes a power storage device (stacked power storage device) 100 (see FIG. 1 ) used as a battery for various vehicles such as forklifts, hybrid vehicles, and electric vehicles. Figure 4 and Figure 5 The power storage module 1 is a secondary battery such as a nickel-hydrogen secondary battery or a lithium-ion secondary battery. In the present embodiment, the case where the power storage module 1 is a lithium-ion secondary battery is exemplified.

[0025] The power storage device 100 includes an electrode stack 3 formed by stacking (laminarizing) a plurality of power storage cells 2. Each power storage cell 2 includes a positive electrode 11, a negative electrode 12, a separator 13, and a sealing portion 14. The positive electrode 11 and the negative electrode 12 are arranged facing each other. The facing direction of the positive electrode 11 and the negative electrode 12 coincides with the stacking direction (first direction) D (Z-axis direction) of the plurality of power storage cells 2. When viewed from the stacking direction D, the positive electrode 11 and the negative electrode 12 are, for example, rectangular electrodes. The power storage cell 2 may also be a large battery with a side exceeding 1 m.

[0026] The positive electrode 11 includes a current collector 21 and a positive electrode active material layer 23. The current collector 21 has a first face 21a and a second face 21b facing opposite directions and an edge 21c. The positive electrode active material layer 23 is provided on the first face 21a. The positive electrode active material layer 23 is not provided on the second face 21b. The edge 21c does not have a positive electrode active material layer 23 on the first face 21a side and the second face 21b side. In other words, the first face 21a has an area where the positive electrode active material layer 23 is not provided at the edge 21c. When viewed from the stacking direction D, the edge 21c is located outside the area where the positive electrode active material layer 23 is provided in the current collector 21. The positive electrode 11 can also be a large electrode with a side exceeding 1m.

[0027] The negative electrode 12 includes a current collector 22 and a negative electrode active material layer 24. The current collector 22 has a first face 22a and a second face 22b facing opposite directions and an edge 22c. The negative electrode active material layer 24 is provided on the first face 22a. In the stacking direction D, the negative electrode active material layer 24 faces the positive electrode active material layer 23. No negative electrode active material layer 24 is provided on the second face 22b. The edge 22c does not have a negative electrode active material layer 24 on the first face 22a side and the second face 22b side. In other words, the first face 22a has an area where the negative electrode active material layer 24 is not provided at the edge 22c. When viewed from the stacking direction D, the edge 22c is located outside the area where the negative electrode active material layer 24 is provided in the current collector 22. The negative electrode 12 can also be a large electrode with one side exceeding 1m.

[0028] The positive electrode 11 and the negative electrode 12 are arranged so that the positive electrode active material layer 23 and the negative electrode active material layer 24 face each other in the stacking direction D. In the present embodiment, the positive electrode active material layer 23 and the negative electrode active material layer 24 are both formed in a rectangular shape when viewed from the stacking direction D. The negative electrode active material layer 24 is formed to be one size smaller than the positive electrode active material layer 23. When viewed from the stacking direction D, the entirety of the positive electrode active material layer 23 is arranged to be closer to the outside than the outer edge of the negative electrode active material layer 24.

[0029] The electrode stack 3 is formed by stacking a plurality of storage cells 2 in such a manner that the second surface 21b of the collector 21 of one storage cell 2 contacts the second surface 22b of the collector 22 of another storage cell 2. Thus, the plurality of storage cells 2 are electrically connected in series. For the storage cells 2, 2 adjacent to each other in the stacking direction D, the collector 21 of one storage cell 2 contacts the collector 22 of another storage cell 2 and are electrically connected to each other. For example, the electrode stack 3 may be a structure in which 30 storage cells 2 are stacked.

[0030] In the electrode stack 3, the power storage units 2, 2 adjacent to each other in the stacking direction D form a pseudo bipolar electrode 10 in which the collectors 21 and the collectors 22 in contact with each other serve as one collector. A terminal positive electrode including the collector 21 is arranged at one end of the electrode stack 3 in the stacking direction D. A terminal negative electrode including the collector 22 is arranged at the other end of the electrode stack 3 in the stacking direction D. The terminal negative electrode provided at one end of the electrode stack 3 in the stacking direction D may also have the collector 22, and the terminal negative electrode provided at the other end of the electrode stack 3 in the stacking direction D may also have the collector 21.

[0031] The current collectors 21 and 22 are chemically inactive conductors for allowing the current to continue to flow in the positive electrode active material layer 23 and the negative electrode active material layer 24 during the discharge or charge of the lithium ion secondary battery. As materials constituting the current collectors 21 and 22, for example, metal materials, conductive resin materials, conductive inorganic materials, etc. can be used. As conductive resin materials, for example, resins obtained by adding conductive fillers to conductive polymer materials and non-conductive polymer materials can be cited. It is also possible that the current collectors 21 and 22 have multiple layers including one or more layers containing the aforementioned metal material or conductive resin material. It is also possible that a coating layer is formed on the surface of the current collectors 21 and 22 by a known method such as plating treatment or spraying. It is also possible that the current collectors 21 and 22 are formed in the form of plates, foils, sheets, sheets, meshes, etc. In the case where the current collectors 21 and 22 are metal foils, for example, aluminum foil, copper foil, nickel foil, titanium foil, or stainless steel foil is used. The current collectors 21 and 22 may also be alloy foils or composite foils of the above-mentioned metals. When the current collectors 21 and 22 are in foil form, the thickness of the current collectors 21 and 22 may also be in the range of 1 μm or more and 100 μm or less. It is also possible that the current collectors 21 and 22 are integrated, for example, by copper plating on one surface of an aluminum foil. In addition, it is also possible that the current collectors 21 and 22 are integrated by bonding. It is also possible that the current collectors 21 and 22 are subjected to surface coating treatments such as evaporation or plating. In the present embodiment, the current collector 21 is an aluminum foil and the current collector 22 is a copper foil.

[0032] The positive electrode active material layer 23 contains a positive electrode active material that can occlude and release charge carriers such as lithium ions. Examples of the positive electrode active material include composite oxides, metallic lithium, and sulfur. The composition of the composite oxide includes, for example, at least one of iron, manganese, titanium, nickel, cobalt, and aluminum and lithium. Examples of the composite oxide include olivine-type lithium iron phosphate (LiFePO4), LiCoO2, and LiNiMnCoO2.

[0033] The negative electrode active material layer 24 contains a negative electrode active material that can occlude and release charge carriers such as lithium ions. Examples of the negative electrode active material include graphite, artificial graphite, highly oriented graphite, mesocarbon microbeads, hard carbon, soft carbon and other carbons, metal compounds, elements or compounds thereof that can form an alloy with lithium, and carbon to which boron is added. Examples of elements that can form an alloy with lithium include silicon (silicon element) and tin.

[0034] In addition to the active material, the positive electrode active material layer 23 and the negative electrode active material layer 24 may also include a binder and a conductive aid. The binder plays the role of maintaining the active material or the conductive aid together and maintaining the conductive network in the electrode. As a binder, examples include: polyvinylidene fluoride, polytetrafluoroethylene, fluorine-containing resins such as fluorine rubber, thermoplastic resins such as polypropylene and polyethylene, imide resins such as polyimide and polyamide-imide, alkoxysilyl-containing resins, acrylic resins such as polyacrylic acid and polymethacrylic acid, styrene-butadiene rubber, carboxymethyl cellulose, sodium alginate, ammonium alginate and other alginates, water-soluble cellulose ester crosslinked bodies, starch-acrylic acid graft polymers. These binders can be used alone or in multiples. Conductive aids are conductive materials such as acetylene black, carbon black, and graphite, which can improve conductivity. Viscosity adjustment solvents, for example, use N-methyl-2-pyrrolidone.

[0035] In order to form the positive electrode active material layer 23 and the negative electrode active material layer 24 on the first surface 21a, 22a, for example, a roll coating method, a die coating method, a dip coating method, a blade coating method, a spray coating method, a curtain coating method, and other conventionally known methods are used. Specifically, the active material, the solvent, and the binder and the conductive aid that can be added as needed are mixed to produce a slurry-like active material layer forming composition, and the active material layer forming composition is applied to the first surface 21a, 22a, and then dried. The solvent is, for example, N-methyl-2-pyrrolidone, methanol, methyl isobutyl ketone, and water. In order to increase the electrode density, the dried material can also be compressed.

[0036] In the stacking direction D, the separator 13 is arranged between the positive electrode 11 and the negative electrode 12. The separator 13 is sandwiched between the positive electrode 11 and the negative electrode 12. The separator 13 is a member that prevents electrical short circuits caused by contact between the two electrodes by isolating the adjacent positive electrode 11 and negative electrode 12 when stacking the storage cells 2, and allows charge carriers such as lithium ions to pass through. The separator 13 is arranged between the positive electrode active material layer 23 and the negative electrode active material layer 24 facing each other.

[0037] When viewed from the stacking direction D, the separator 13 is formed into a rectangular shape that is one circle larger than the positive electrode active material layer 23 and the negative electrode active material layer 24 and one circle smaller than the collectors 21 and 22. When viewed from the stacking direction D, the end 13c of the separator 13 is arranged outside the positive electrode active material layer 23 and the negative electrode active material layer 24. When viewed from the stacking direction D, the end 13c of the separator 13 does not overlap with the positive electrode active material layer 23 and the negative electrode active material layer 24.

[0038] The separator 13 is formed in a sheet shape, for example. The separator 13 is, for example, a porous sheet or nonwoven fabric containing a polymer that absorbs and retains the electrolyte. Examples of materials constituting the separator 13 include polypropylene, polyethylene, polyolefin, polyester, and the like. The separator 13 may be a single-layer structure or a multi-layer structure. Alternatively, in the case of a multi-layer structure, the separator 13 may include, for example, a substrate layer and a pair of adhesive layers, which are bonded and fixed to the positive electrode active material layer 23 and the negative electrode active material layer 24 by a pair of adhesive layers. Alternatively, the separator 13 may include a ceramic layer that serves as a heat-resistant layer. Alternatively, the separator 13 may be reinforced by a vinylidene fluoride resin compound.

[0039] As the electrolyte impregnated in the diaphragm 13, for example, can be cited: a liquid electrolyte (electrolyte 5) comprising a non-aqueous solvent and an electrolyte salt dissolved in the non-aqueous solvent. When the diaphragm 13 is impregnated with an electrolyte, as the electrolyte salt, LiClO4, LiAsF6, LiPF6, LiBF4, LiCF3SO3, LiN(FSO2)2, LiN(CF3SO2)2 and other known lithium salts can be used. In addition, as the non-aqueous solvent, known solvents such as cyclic carbonates, cyclic esters, chain carbonates, chain esters, ethers can be used. In addition, two or more of these known solvent materials can also be used in combination.

[0040] In the electrode stack 3, when the positive electrode 11 arranged in the outermost layer, i.e., the positive electrode 11 constituting one end of the electrode stack 3 in the stacking direction D, is set as the terminal positive electrode, and the negative electrode 12 constituting the other end of the electrode stack 3 in the stacking direction D is set as the terminal negative electrode, the second surface 21b of the collector 21 on which the positive electrode active material layer 23 is not formed in the terminal positive electrode and the second surface 22b of the collector 22 on which the negative electrode active material layer 24 is not formed in the terminal negative electrode are formed with exposed surfaces 21e and 22e exposed to the outside. The exposed surfaces 21e and 22e are surfaces with which the conductive plate 7 contacts when the power storage module 1 is stacked.

[0041] The sealing portion 14 is a member for sealing the internal space S between the current collector 21 and the current collector 22. When viewed from the stacking direction D, the sealing portion 14 is frame-shaped and surrounds the positive electrode active material layer 23 and the negative electrode active material layer 24. The sealing portion 14 forms an internal space S that is divided relative to the outside for accommodating the electrolyte 5 between the current collector 21 and the current collector 22. In the storage cell 2, the internal space S is divided by the current collector 21, the current collector 22 and the sealing portion 14. The electrolyte 5 is accommodated in the internal space S. The sealing portion 14 is formed of a resin material having electrolyte resistance, such as acid-modified polyethylene (acid-modified PE), acid-modified polypropylene (acid-modified PP), polyethylene or polypropylene. The sealing portion 14 has electrical insulation.

[0042] The sealing portion 14 includes a sealing body portion (body portion) 140 and a liquid injection portion 50. The sealing body portion 140 is formed by including a first resin portion 15, a second resin portion 16, and an end face weld portion 17. The sealing body portion 140 has a thickness in the X-axis direction and the Y-axis direction. When viewed from the stacking direction D, the first resin portion 15, the second resin portion 16, and the end face weld portion 17 are each frame-shaped. The first resin portion 15 is arranged at the edge of the collector 21 and the collector 22 in a manner separated from the positive electrode active material layer 23 and the negative electrode active material layer 24 in the bipolar electrode 10. That is, there is a space between the inner peripheral surface of the first resin portion 15 and the outer peripheral surface of the positive electrode active material layer 23, and there is a space between the inner peripheral surface of the first resin portion 15 and the outer peripheral surface of the negative electrode active material layer 24. Furthermore, the first resin portion 15 is provided so as to cover the first surface 21 a of the current collector 21 and the first surface 22 a of the current collector 22 at the edge portions of the current collector 21 and the current collector 22 .

[0043] The first resin portion 15 is provided at the edge of the current collector 21 in a manner separated from the positive electrode active material layer 23 at the terminal positive electrode constituting one end of the electrode stack 3 in the stacking direction D. That is, there is a space between the inner peripheral surface of the first resin portion 15 and the outer peripheral surface of the positive electrode active material layer 23. In addition, the first resin portion 15 is provided to cover the first surface 21a and the second surface 21b at the edge of the current collector 21. The first resin portion 15 is provided at the edge of the current collector 22 in a manner separated from the negative electrode active material layer 24 at the terminal negative electrode constituting the other end of the electrode stack 3 in the stacking direction D. That is, there is a space between the inner peripheral surface of the first resin portion 15 and the outer peripheral surface of the negative electrode active material layer 24. In addition, the first resin portion 15 is provided to cover the first surface 22a and the second surface 22b at the edge of the current collector 22.

[0044] In the Z-axis direction, the second resin portion 16 is arranged between the first resin portion 15 and the first resin portion 15. The second resin portion 16 has a function as a joining portion for joining the first resin portions 15 and 15 to each other and a function as a spacing holding portion for holding the spacing between the first resin portions 15 and 15. Like the first resin portion 15, the second resin portion 16 is arranged to be separated from the positive electrode active material layer 23 and the negative electrode active material layer 24. That is, there is a space between the inner peripheral surface of the second resin portion 16 and the outer peripheral surface of the positive electrode active material layer 23, and there is a space between the inner peripheral surface of the second resin portion 16 and the outer peripheral surface of the negative electrode active material layer 24. The second resin portion 16 is joined to the first resin portion 15 by welding.

[0045] The end face weld 17 integrates the first resin part 15 and the second resin part 16 by welding the outer edge of the first resin part 15 and the outer edge of the second resin part 16. When viewed from the stacking direction D, the end face weld 17 is formed on at least one surface of the outer peripheral surface of the first resin part 15 and the second resin part 16. When viewed from the stacking direction D, the end face weld 17 is formed in a region outside the outer edge of the collector 21 and the collector 22. In the present embodiment, the end face weld 17 is formed on all four surfaces forming the outer peripheral surface of the first resin part 15 and the second resin part 16. It is also possible that the thickness (length in the direction orthogonal to the first direction) of the end face weld 17 on the surface where the injection port 51 is not formed is greater than the thickness of the end face weld 17 on the surface where the injection port 51 is formed.

[0046] The sealing body 140 is formed into a rectangular tube shape by integrating a plurality of first resin parts 15 and second resin parts 16 arranged in the stacking direction D of the electrode stack 3 by welding, and welding the outer edge of the first resin part 15 to the outer edge of the second resin part 16 by the end face welding part 17. The sealing body 140 of the sealing part 14 is formed on a side surface 140a extending from the first resin part 15 provided at the collector 21 arranged at one end of the electrode stack 3 in the stacking direction D to the second resin part 16 provided at the collector 22 arranged at the other end of the electrode stack 3 in the stacking direction D. In other words, the sealing body 140 is formed with the same side surface 140a as the stacking direction D ( Figure 3 The direction perpendicular to the Z-axis direction shown in the figure) Figure 3 The side surfaces 140a of the sealing body 140 are also the side surfaces of the sealing portion 14 and also serve as the side surfaces of the power storage module 1.

[0047] As described above, when viewed from the Z-axis direction, the sealing body 140 is a cylindrical body formed in a rectangular frame shape in a manner surrounding the electrode stack 3. The sealing body 140 has thickness in the X-axis direction and the Y-axis direction. A plurality of communication paths 140b are provided on the side of one side surface 140a of the sealing body 140 formed as a cylindrical body, each of which communicates with a plurality of internal spaces S. An opening (end) of the communication path 140b is formed on one side surface 140a of the sealing body 140.

[0048] The liquid injection part 50 is provided for injecting the electrolyte 5 into the internal space S in the sealing part 14. The liquid injection part 50 is provided on one side surface 140a of the above-mentioned four side surfaces 140a. The liquid injection part 50 has a plurality of liquid injection ports 51 which are mounted on one side surface 140a of the sealing main body 140 and are respectively connected to the communication path 140b. The liquid injection part 50 has a liquid injection main body 52, a liquid injection frame 53, and an extension part 54. The liquid injection main body 52 is a portion covering the side surface 140a. The liquid injection main body 52 of this embodiment covers a portion of one side surface 140a of the above-mentioned four side surfaces 140a.

[0049] The injection frame 53 protrudes from the injection body 52 and is provided to connect the connection portion of the injection device of the electrolyte 5 to the communication path 140b in a fully sealed state (maintaining airtightness) when the electrolyte 5 is injected into the internal space S of the power storage module 1. In other words, the injection frame 53 has a frame-shaped sealing surface for the connection portion of the injection device to press against. The frame-shaped sealing surface is configured to be formed flat in the X-axis direction, for example, to allow a rubber pad or the like provided in the injection device of the electrolyte 5 to be in close contact.

[0050] Here, a plurality of communication paths 140b are provided in the Z-axis direction (first direction) of the sealing body 140, and a plurality of communication path groups are provided in the Z-axis direction (first direction). In the present embodiment, three communication paths 140b are arranged in the Z-axis direction, and a communication path group consisting of three communication paths 140b in the Z-axis direction is arranged along the Y-axis direction. The communication path 140b opens on the side surface 140a of the sealing body 140 along the Z-axis direction, and opens at the injection body 52 surrounded by the injection frame 53, and is connected to the internal space S from the outside of the module.

[0051] The injection frame 53 is formed in the injection body 52, and the openings of the plurality of communication paths 140b arranged along the Z-axis direction are independent of each other and the plurality of communication paths 140b are surrounded to form the above-mentioned injection port 51. The injection frame 53 of this embodiment is a frame that opens (communicates) the communication paths 140b to the outside and forms the injection port 51. In more detail, the injection frame 53 protrudes from the injection body 52 in a manner that surrounds the end of one communication path 140b. The injection port 51 is formed by the inner peripheral surface (inner wall) of the injection frame 53 that protrudes from the injection body 52 in a manner that surrounds the end of one communication path 140b.

[0052] The injection port 51 is provided corresponding to a communication path 140b provided respectively with respect to a plurality of internal spaces S. In more detail, the sealing portion 14 of the power storage module 1 has 10 injection frames 53 having three injection ports 51 arranged in the Y-axis direction. That is, 30 injection ports 51 are provided in the sealing portion 14 of the power storage module 1. The shape of the injection port 51 observed from the extension direction (X-axis direction) of the injection port 51 is, for example, formed into a rectangle (rectangle) that is longer in one direction (Y-axis direction). In addition, the shape of the injection port 51 is not limited, and for example, it can also be formed in a circular shape. The injection port 51 is sealed by the sealing portion after the injection of the electrolyte.

[0053] As described above, 10 injection frames 53 are formed in the Y-axis direction on the side surface 140a of the sealing part 14. The plurality of injection frames 53 include: a first injection frame 50A, which makes a part of the injection frame 53 protrude from the sealing body part 140 only on one side in the stacking direction D (Z-axis direction); and a second injection frame 50B, which makes a part of the injection frame 53 protrude from the sealing body part 140 only on the other side in the stacking direction D (Z-axis direction). In other words, there are at least two types of injection frames in the plurality of injection frames 53. In addition, the part of the injection frame 53 protrudes from the sealing body part 140, which means that when viewed from the X-axis direction, a part of the outer shape 53a of the injection frame 53 protrudes from the sealing body part 140 in the stacking direction D (Z-axis direction).

[0054] like Figure 3As shown in the figure, in the first injection frame 50A, it is sufficient that the upper portion of the injection frame 53 protrudes from the sealed main body 140 in the stacking direction D, and the lower portion of the injection frame 53 protrudes from the sealed main body 140 in the stacking direction D less than the upper portion of the injection frame 53. Alternatively, the lower portion of the injection frame 53 does not protrude from the sealed main body 140 in the stacking direction D. In the second injection frame 50B, it is sufficient that the lower portion of the injection frame 53 protrudes from the sealed main body 140 in the stacking direction D, and the upper portion of the injection frame 53 protrudes from the sealed main body 140 in the stacking direction D less than the lower portion of the injection frame 53. Alternatively, the upper portion of the injection frame 53 does not protrude from the sealed main body 140 in the stacking direction D.

[0055] In the present embodiment, a portion of the plurality of injection frames 53 included in the power storage module 1 is a first injection frame 50A in which a portion of the injection frame 53 protrudes from the sealing body 140 only on one side in the stacking direction D, and the remainder of the plurality of injection frames 53 is a second injection frame 50B in which a portion of the injection frame 53 protrudes from the sealing body 140 only on the other side in the stacking direction D. In other words, the power storage module 1 does not have an injection frame 53 other than the first injection frame 50A and the second injection frame 50B. Moreover, in the power storage module 1 of the present embodiment, the same number of first injection frames 50A and second injection frames 50B are provided. Specifically, five first injection frames 50A and five second injection frames 50B are provided.

[0056] As described above, four side surfaces 140a are formed in the power storage module 1, and a plurality of injection frames 53 are formed on one side surface 140a and arranged along the Y-axis direction orthogonal to the stacking direction D (Z-axis direction). In the present embodiment, five first injection frames 50A are arranged continuously in the Y-axis direction, and five second injection frames 50B are arranged continuously. In addition, a connection portion 55 is formed between adjacent injection frames 53, 53. In the X-axis direction, the connection portion 55 has a surface formed coplanar with the sealing surface of the injection frame 53.

[0057] A laminate film 59 (see FIG. 5 ) covering the liquid injection port 51 is attached to the liquid injection frame 53. Figure 3 ). The laminate film 59 can be, for example, a known composite laminate film obtained by bonding a metal foil and a resin layer. The metal foil of the composite laminate film can be, for example, aluminum, aluminum alloy, stainless steel, nickel alloy, etc. The resin layer of the composite laminate film can be, for example, polyethylene, ethylene-vinyl acetate, polyethylene terephthalate, etc. Figure 1 and Figure 2 In the figure, the laminate film 59 is omitted.

[0058] Such a liquid injection frame 53 can be formed integrally with the sealing portion 14 by, for example, injection molding. When viewed from the stacking direction D, the liquid injection portion 50 has an overhanging portion (thickened portion) 54 that overlaps the sealing main body 140. The overhanging portion 54 is connected to the sealing main body 140 and covers parts of the two end surfaces of the electrode stack 3 in the stacking direction D. The liquid injection frame 53 and the overhanging portion 54 can be connected to the sealing main body 140 by welding. Alternatively, the liquid injection frame 53 and the overhanging portion 54 can be formed simultaneously on the sealing main body 140 by injection molding.

[0059] A sheet member 18 having a metal layer is attached to the surface of the sealing portion 14 that is orthogonal to the stacking direction D, that is, the frame-shaped first surface 14b and the second surface 14c formed at both ends of the electrode stack 3. In addition, a sheet member 18 is also attached to the outer surface of the injection portion 50 formed at the side surface 140a of the injection frame 53 formed on the sealing portion 14. In this structure, the metal layer contained in the sheet member 18 is a material with a lower permeability coefficient of hydrogen or water than the resin. Therefore, the sheet member 18 has a higher barrier property with respect to water, and therefore, compared with the case where the sealing portion 14 is composed only of a resin material, the intrusion of water into the interior of the storage module through the sealing portion 14 is suppressed.

[0060] Here, the sheet member 18 may also be a laminated film. As the laminated film, for example, a known composite laminated film obtained by bonding a metal foil and a resin layer can be used. The metal foil of the composite laminated film can be made of, for example, aluminum, aluminum alloy, stainless steel, nickel alloy, etc. The resin layer of the composite laminated film can be made of, for example, polyethylene, ethylene-vinyl acetate, polyethylene terephthalate, etc.

[0061] like Figure 4 and Figure 5 As shown, the power storage device 100 is constructed by stacking the above-mentioned power storage modules 1 in the Z-axis direction and electrically connecting a plurality of power storage modules 1 in series. In more detail, the power storage device 100 is constructed by contacting and configuring a conductive plate 7 on exposed surfaces 21e and 22e formed at both ends of the power storage module 1 and stacking the power storage modules 1 with the conductive plate 7 interposed therebetween. In the power storage device 100, a plurality of liquid injection portions 50 formed on respective side surfaces 140a of a plurality of power storage modules 1 are arranged in an aligned manner in the Z-axis direction. In other words, the liquid injection portions 50 of the power storage modules 1 constituting the power storage device 100 are arranged in a straight line in the Z-axis direction, and the liquid injection portions 50 are arranged in a grid shape when viewed from the X-axis direction. In addition, Figure 5 In the figure, the communication path 140b and the liquid injection port 51 are omitted.

[0062] In more detail, the power storage device 100 stacks multiple power storage modules 1 so that the direction in which the first liquid injection frame 50A protrudes from the sealing body 140 (one side in the first direction) is above the vertical direction, and the direction in which the second liquid injection frame 50B protrudes from the sealing body 140 (the other side in the first direction) is below the vertical direction, and the first liquid injection frame 50A is arranged along the vertical direction and the second liquid injection frame 50B is arranged along the vertical direction.

[0063] Furthermore, when the storage modules 1 and 1 adjacent in the vertical direction are observed, the first liquid injection frame 50A arranged in the stacking direction D is such that a gap is provided between the lower end of the first liquid injection frame 50A of one storage module 1 and the upper end of the first liquid injection frame 50A of another storage module 1. Furthermore, when the storage modules 1 adjacent in the vertical direction are observed, the second liquid injection frame 50B arranged in the stacking direction D is such that a gap is provided between the lower end of the second liquid injection frame 50B of one storage module 1 and the upper end of the second liquid injection frame 50B of another storage module 1. Such two gaps are provided by adjusting the thickness of the conductive plate 7 arranged between the storage modules 1 and 1 adjacent in the stacking direction D. Thus, the occurrence of poor electrical contact between the modules and the conductive plate caused by the contact between the liquid injection frames 53 and 53 of the modules adjacent in the stacking direction D can be suppressed.

[0064] Furthermore, in such an electric storage device 100, when the electric storage modules 1 adjacent in the stacking direction are viewed from the X-axis direction, the lower end of the second liquid injection frame 50B of one electric storage module 1 is located below the upper end of the first liquid injection frame 50A of the other electric storage module 1. Thus, due to the height difference between the first liquid injection frame 50A and the second liquid injection frame 50B in the stacking direction D, if one of the electric storage modules 1, 1 adjacent in the stacking direction D (Z-axis direction) moves in the lateral direction (Y-axis direction), the protrusion of one of the electric storage modules 1 contacts the protrusion of the other electric storage module 1. Thus, it is possible to restrict the electric storage modules 1, 1 from moving relative to each other in the Y-axis direction orthogonal to the stacking direction D. That is, it can be utilized in positioning when stacking the electric storage modules 1.

[0065] The effects of the power storage module 1 and the power storage device 100 of the above embodiment will be described. The power storage device 100 of the above embodiment is formed by stacking a plurality of power storage modules 1. In the power storage module 1 of the present embodiment, the injection frame 53 provided at the injection portion 50 for injecting the electrolyte 5 is made to protrude from the sealing body 140 in the Z-axis direction, which is the stacking direction D. However, the first injection frame 50A is larger than the second injection frame 50B in terms of the amount of protrusion of a part of the injection frame 53 from the sealing body 140 on the upper side in the Z-axis direction, and the second injection frame 50B is larger than the first injection frame 50A in terms of the amount of protrusion of a part of the injection frame 53 from the sealing body 140 on the lower side in the Z-axis direction. As a result, it is possible to prevent the portions that protrude greatly from the sealing body 140 from facing each other in the stacking direction D, and to suppress the increase in the size in the stacking direction D when the power storage device 100 is assembled.

[0066] In the power storage module 1 of the above embodiment, the plurality of liquid injection frames 53 are composed of a first liquid injection frame 50A whose part protrudes from the sealing body 140 only on the upper side in the Z-axis direction, and a second liquid injection frame 50B whose part protrudes from the sealing body 140 only on the lower side in the Z-axis direction. In other words, for each of the first liquid injection frame 50A and the second liquid injection frame 50B of the above embodiment, one side (upper side or lower side) in the Z-axis direction does not protrude from the sealing body 140. Therefore, it is possible to prevent the parts that greatly protrude from the sealing body 140 from facing each other in the stacking direction D, and it is possible to suppress the increase in the stacking direction dimension when assembled as the power storage device 100.

[0067] In the power storage module 1 of the above embodiment, only the first liquid injection frame 50A and the second liquid injection frame 50B are provided as the liquid injection frame 53. Thus, the structure of the liquid injection frame 53 can be concentrated into the structure of the first liquid injection frame 50A and the structure of the second liquid injection frame 50B, so that the productivity of the power storage module 1 can be improved. In addition, in the power storage module 1 of the above embodiment, the same number of first liquid injection frames 50A and second liquid injection frames 50B are provided, so that symmetry is ensured, and therefore, the balance when the power storage modules 1 are stacked is excellent.

[0068] In the power storage module 1 of the above embodiment, four side surfaces 140a are formed on the frame-shaped sealing portion 14. Figure 2 and Figure 3 As shown, a plurality of injection frames 53 are formed on one side surface 140a and arranged along the Y-axis direction orthogonal to the stacking direction D. This makes it easier to inject the electrolyte 5 than in a power storage module 1 having a structure in which the injection frames 53 are dispersedly formed on a plurality of side surfaces 140a.

[0069] In the power storage module 1 of the above embodiment, Figure 2 and Figure 4 As shown in the figure, the first injection frames 50A are arranged continuously in the Y-axis direction, and the second injection frames 50B are arranged continuously in the Y-axis direction. In this structure, the height difference between the first injection frames 50A and the second injection frames 50B can limit the situation where the storage modules 1, 1 adjacent to each other in the stacking direction D want to move in the Y-axis direction.

[0070] In the power storage module 1 of the above-described embodiment, metal sheet members 18 are attached to the surfaces of the sealing portion 14 that are orthogonal to the stacking direction D, that is, to the frame-shaped first surface 14b and the second surface 14c disposed at both ends of the electrode stack 3. The metal sheet member 18 has a lower permeability coefficient with respect to water than the resin, and therefore, compared with the case where the sealing portion 14 is constituted only, the intrusion of water into the inside of the sealing portion 14 is suppressed.

[0071] In the power storage module 1 of the above embodiment, exposed surfaces 21e and 22e exposed to the outside are formed on the second surface 21b of the current collector 21 constituting the positive electrode 11 and the second surface 22b of the current collector 22 constituting the negative electrode 12 arranged at both ends of the electrode stack 3. In the power storage module 1 having such a structure, a plurality of power storage modules 1 can be electrically connected in series by a simple operation of stacking the power storage modules 1 with the conductive plates 7 placed on the exposed surfaces 21e and 22e.

[0072] In the power storage module 1 of the above embodiment, the liquid injection portion 50 further includes an extension portion 54, which is connected to the sealing body portion 140 and covers parts of both end surfaces of the electrode stack 3 in the stacking direction D (Z-axis direction). Thus, the liquid injection portion 50 can be provided more stably with respect to the sealing body portion 140.

[0073] In the power storage module 1 of the above embodiment, the laminate film 59 covering the injection port 51 is attached to the first injection frame 50A and the second injection frame 50B. This seals the injection port 51 and the communication path 140b, thereby blocking the communication between the internal space S and the outside.

[0074] Although one embodiment has been described above, one aspect of the present invention is not limited to the above embodiment and various modifications can be made without departing from the gist of the invention.

[0075] In the above embodiment, if Figure 4As shown in FIG. 1 , an example is given in which the first liquid injection frame 50A is arranged continuously in the Y-axis direction orthogonal to the stacking direction D and the second liquid injection frame 50B is arranged continuously in the Y-axis direction, but one aspect of the present invention is not limited to this. For example, in the power storage module 1A according to the modified example, Figure 6 As shown in FIG. 1 , the first liquid injection frame 50A and the second liquid injection frame 50B are alternately arranged in the Y-axis direction. In the structure of the power storage device 100A in which the power storage modules 1 of this modified example are stacked, the second liquid injection frame 50B fits in the height difference of the pair of first liquid injection frames 50A, 50A, and the first liquid injection frame 50A fits in the height difference of the pair of second liquid injection frames 50B, 50B. Thus, it is possible to restrict the power storage modules 1, 1 adjacent to each other in the stacking direction D from moving in the Y-axis direction.

[0076] in addition, Figure 6 Although an example in which the metal sheet member 18 is not provided is described, the metal sheet member 18 may be attached to the frame-shaped first surface 14 b and the second surface 14 c formed at both ends of the electrode stack 3 .

[0077] In the above-mentioned embodiment and the above-mentioned variation example, an example in which only the first injection frame 50A and the second injection frame 50B are provided on the side surface 140a of the sealing part 14 is cited for explanation, but it may also be that, in addition to these injection frames 53, it may also include: an injection part 50 having such an injection frame 53 that a part of the injection frame 53 does not protrude from the sealing main body 140 on both one side and the other side in the stacking direction D, and an injection part 50 having such an injection frame 53 that a part of the injection frame 53 protrudes from the sealing main body 140 on both one side and the other side in the stacking direction D.

[0078] The number of the injection frames 53 shown in the above-mentioned embodiment and the above-mentioned modification, the number of the injection ports 51 formed in one injection frame 53, the number of the first injection frame 50A and the second injection frame 50B, and the arrangement method can be appropriately changed in accordance with the number of internal spaces S formed in the power storage module 1. For example, in the power storage module 1 arranged in a manner such that the stacking direction D is along the vertical direction, only one injection frame 53 having the injection port 51 corresponding to the communication path 140b communicating with the internal space S arranged at the top may be set as the first injection frame 50A, only one injection frame 53 having the injection port 51 corresponding to the communication path 140b communicating with the internal space S arranged at the bottom may be set as the second injection frame 50B, and the remaining injection frame 53 may be configured as a third injection frame in which a part thereof does not protrude from the sealing body 140 in the stacking direction D.

[0079] In the above-mentioned embodiment and the above-mentioned modification example, an example is given in which all the liquid injection frames 53 are arranged on one side surface 140a of the multiple side surfaces 140a of the sealing portion 14 for explanation, but the present invention is not limited to this. For example, it is also possible that multiple liquid injection frames 53 are dispersedly arranged on multiple side surfaces 140a.

[0080] Description of Reference Numerals

[0081] 1, 1A...power storage module; 2...power storage unit; 3...electrode stack; 5...electrolyte; 7...conductive plate; 11...positive electrode; 12...negative electrode; 14...sealing portion; 18...sheet member; 21...current collector; 21e...exposed surface; 22...current collector; 22e...exposed surface; 50...liquid injection portion; 50A...first liquid injection frame; 50B...second liquid injection frame; 51...liquid injection port; 53...liquid injection frame; 100, 100A...power storage device; 140...sealed main body (main body); 140a...side surface; 140b...connecting path; D...stacking direction (first direction); S...internal space.

Claims

1. A power storage module for a stacked power storage device, characterized in that: have: an electrode stack having bipolar electrodes stacked along a first direction, the bipolar electrode having a positive electrode formed on a first surface of a current collector and a negative electrode formed on a second surface opposite to the first surface; and a sealing portion that forms an internal space between the current collectors adjacent to each other in the first direction and seals the internal space, The sealing portion has: a main body portion, which is a cylindrical body formed in a rectangular frame shape so as to surround the electrode stack when viewed from the first direction, and a plurality of communication paths communicating with each of the plurality of internal spaces are provided on one side surface of the cylindrical body; as well as a liquid injection portion having a plurality of liquid injection ports, the plurality of liquid injection ports being mounted on the one side surface of the main body portion and being communicated with the communication paths respectively; The liquid injection part includes a plurality of liquid injection frames, the liquid injection frames make the ends of the plurality of communication paths arranged along the first direction independent of each other and surround the ends of the plurality of communication paths to form the liquid injection port, and the plurality of liquid injection frames are arranged on the one side surface of the main body along a second direction orthogonal to the first direction, The plurality of liquid injection frames arranged along the second direction include: a first liquid injection frame in which a portion of the liquid injection frame protrudes from the main body at least on one side in the first direction, and a second liquid injection frame in which a portion of the liquid injection frame protrudes from the main body at least on the other side in the first direction, Regarding the amount of protrusion of a part of the liquid injection frame from the main body on one side in the first direction, the protrusion of the first liquid injection frame is greater than the protrusion of the second liquid injection frame, Regarding the amount of protrusion of the portion of the liquid injection frame from the main body on the other side in the first direction, the protrusion amount of the second liquid injection frame is greater than the protrusion amount of the first liquid injection frame.

2. The power storage module according to claim 1, characterized in that: For the first liquid injection frame, a portion of the liquid injection frame protrudes from the main body only on one side in the first direction. Regarding the second liquid injection frame, a portion of the liquid injection frame protrudes from the main body only on the other side in the first direction.

3. The power storage module according to claim 1 or 2, characterized in that: The first liquid injection frame and the second liquid injection frame are each provided with a plurality of The first liquid injection frames are arranged continuously in the second direction, and the second liquid injection frames are arranged continuously in the second direction.

4. The power storage module according to any one of claims 1 to 3, characterized in that: The first liquid injection frame and the second liquid injection frame are each provided with a plurality of The first liquid injection frames and the second liquid injection frames are alternately arranged in the second direction.

5. The power storage module according to any one of claims 1 to 4, characterized in that: The liquid injection portion further includes an overhanging portion connected to the main body portion and covering parts of both end surfaces of the electrode stack in the first direction.

6. The power storage module according to any one of claims 1 to 5, characterized in that: A laminate film covering the liquid injection port is attached to the liquid injection frame.

7. The power storage module according to any one of claims 1 to 6, characterized in that: In the stack, the positive electrode at one end of the stack in the first direction is set as the terminal positive electrode, and the negative electrode at the other end of the stack in the first direction is set as the terminal negative electrode. An exposed surface exposed to the outside is formed on one surface of the collector where the positive electrode is not formed in the terminal positive electrode and on one surface of the collector where the negative electrode is not formed in the terminal negative electrode.

8. An electric storage device, characterized in that: have: An electrically conductive plate and a plurality of the power storage modules according to claim 7, The power storage modules are stacked in the first direction via the conductive plates in contact with the exposed surfaces.

9. The power storage device according to claim 8, characterized in that When the power storage modules are stacked so that the one side is vertically upward and the other side is vertically downward and the first liquid filling frames are arranged along the vertical direction and the second liquid filling frames are arranged along the vertical direction, When the electricity storage modules adjacent to each other in the vertical direction are viewed, the lower end of the second liquid filling frame of one of the electricity storage modules is located below the upper end of the first liquid filling frame of the other electricity storage module.

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