Battery

Abstract

The invention relates to a battery. This battery is provided with: an electrode laminate in which electrodes including current collectors and active material layers divided by having grooves therebetween are laminated; a sealing body that forms an internal space in which the electrolyte solution is accommodated between the current collectors, and that seals the internal space; and a liquid injection port that is formed in the sealing body and that connects the inside space and the outside, the inside space being formed by the groove and an uncoated region in which the active material layer is not provided around the active material layer, and the inside region sealed by the sealing body having a polygonal shape when viewed from the lamination direction of the electrode laminate. The grooves extend between the active material layers from the liquid injection port side in the direction opposite to the liquid injection port side, the grooves include grooves A and grooves B having different widths, and the width of the grooves A is larger than the width of the grooves B.

Description

Technical Field

[0001] The present disclosure relates to batteries. Background Art

[0002] As a conventional method for manufacturing a battery, there is known a method including a step of injecting an electrolyte solution into a space between electrodes disposed opposite to each other with a separator interposed therebetween (for example, see Japanese Patent Application Laid-Open No. 2013-191450).

[0003] In addition, Japanese Patent Publication No. 2022-188536 discloses a method for manufacturing a bipolar storage device, comprising: a first decompression step, in which the internal space is decompressed to a first pressure when the electrolyte is allowed to penetrate into the internal space of the battery; a first injection step, in which a specified amount of electrolyte is injected into the internal space after the decompression in the first decompression step from a predetermined retaining portion for retaining a specified amount of electrolyte through an injection port; a second decompression step, in which the internal space into which the specified amount of electrolyte is injected is decompressed to a second pressure through the retaining portion and the injection port, so that a portion of the electrolyte flows back from the internal space to the retaining portion; and a second injection step, in which the interior of the retaining portion for retaining the reverse-flowing electrolyte is made to have a pressure higher than the second pressure, and the electrolyte is injected into the internal space from the retaining portion through the injection port, and the second decompression step includes an initial decompression step of decompressing the internal space at a decompression rate lower than that of the first decompression step S20.

[0004] In addition, in previous batteries, from the viewpoint of increasing battery capacity, research has been conducted to reduce the volume (width) of the uncoated region on the current collector where the active material layer is not formed. However, when the width of the uncoated region is made too small, there is a problem that the liquid permeability of the electrolyte relative to the groove provided in the active material layer deteriorates. Summary of the invention

[0005] Problems to be solved by the invention

[0006] The present disclosure has been made in view of the above circumstances, and an object of the present disclosure is to provide a battery having improved permeability of an electrolyte solution into an active material layer.

[0007] Means for solving problems

[0008] Means for solving the above-mentioned problems include the following aspects.

[0009] <1> A battery comprising: an electrode stack formed by stacking electrodes including a current collector and an active material layer, wherein the active material layer is provided on one or both surfaces of the current collector, and the active material layer is divided into a plurality of regions by providing a plurality of grooves between the active material layers;

[0010] a sealing body that forms an internal space for accommodating an electrolyte between adjacent current collectors and seals the internal space; and

[0011] A liquid injection port is formed in the sealing body to connect the internal space with the outside.

[0012] The inner space is formed by the groove and an uncoated area around the active material layer where the active material layer is not provided.

[0013] The inner region sealed by the sealing body is polygonal in shape when viewed from the stacking direction of the electrode stack.

[0014] When the surface of the sealing body on the inner space side of the side where the liquid injection port is formed is set as the liquid injection port side surface,

[0015] The groove extends between the active material layers from the side surface of the liquid injection port toward a direction opposite to the side surface of the liquid injection port.

[0016] The plurality of grooves include at least a groove A and a groove B having different widths, and the width of the groove A is greater than the width of the groove B.

[0017] <2> The battery according to <1>,

[0018] The inner region sealed by the sealing body is a quadrilateral when viewed from the stacking direction of the electrode stack.

[0019] The sealing body has the liquid injection port only in a region facing one side of the quadrilateral.

[0020] <3> The battery according to <1> or <2>,

[0021] At least one of the grooves A satisfies at least one of the following requirements (A1) and (A2),

[0022] (A1) is provided at a position closest to the liquid injection port among the plurality of grooves.

[0023] (A2) In the direction in which the plurality of grooves are arranged, the groove is provided at a position closest to a position that is equidistant from a groove provided at the end and a groove provided at an end on the opposite side.

[0024] <4> The battery according to any one of <1> to <3>,

[0025] The width of the groove B [d B ] relative to the width of the groove A [d A ] ratio ([d B ] / [d A ]) is greater than 0.07 and less than 0.40.

[0026] <5> The battery according to any one of <1> to <4>,

[0027] The width of the groove B [d B ] is greater than 0.5 mm and less than 4.0 mm.

[0028] Effects of the Invention

[0029] According to the present disclosure, a battery having improved permeability of an electrolyte solution into an active material layer is provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a schematic cross-sectional view showing the structure of a bipolar power storage device according to an embodiment.

[0031] Figure 2 Yes means Figure 1 A schematic cross-sectional view of the internal structure of the power storage module shown.

[0032] Figure 3 yes Figure 2 A cross-sectional view of the power storage module shown is taken orthogonally to the stacking direction.

[0033] Description of symbols

[0034] 1 bipolar power storage device, 11 electrode stack, 12 sealing body, 13 separator, 14 bipolar electrode, 15 metal plate (collector), 15a one surface, 15b the other surface, 16 positive electrode, 17 negative electrode, D stacking direction, P liquid injection port, V internal space. DETAILED DESCRIPTION

[0035] Hereinafter, a battery according to an embodiment of the present disclosure will be described with reference to the drawings. In the description of the drawings, the same reference numerals are used for the same or equivalent elements, and duplicate descriptions are omitted.

[0036] Figure 1 It is a schematic cross-sectional view showing the structure of a bipolar power storage device according to an embodiment. Figure 1 The bipolar power storage device 1 shown (hereinafter also referred to as "power storage device 1") is a device used as a battery for various vehicles such as forklifts, hybrid vehicles, and electric vehicles. The power storage device 1 is, for example, a secondary battery such as a nickel-hydrogen secondary battery or a lithium-ion secondary battery. In this embodiment, the case where the power storage device 1 is a lithium-ion secondary battery is exemplified. The power storage device 1 includes a module stack 2 and a restraining member 3 that applies a restraining load to the module stack 2 in the stacking direction of the module stack 2.

[0037] The module stack 2 includes power storage modules 4 and conductive plates 5 stacked on the power storage modules 4. The module stack 2 includes a plurality of (here, three) power storage modules 4 and a plurality of (here, four) conductive plates 5. The power storage modules 4 are bipolar batteries and are rectangular in shape when viewed from the stacking direction.

[0038] The storage modules 4 adjacent to each other in the stacking direction are electrically connected to each other via the conductive plates 5. The conductive plates 5 are respectively arranged between the storage modules 4 adjacent to each other in the stacking direction and outside the storage modules 4 located at the stacking end. The positive terminal 6 is connected to the conductive plate 5 arranged on one side outside the storage module 4 located at the stacking end. The negative terminal 7 is connected to the conductive plate 5 arranged on the other side outside the storage module 4 located at the stacking end. The positive terminal 6 and the negative terminal 7 are drawn out from the edge of the conductive plate 5 in a direction intersecting the stacking direction, for example. The storage device 1 is charged and discharged through the positive terminal 6 and the negative terminal 7.

[0039] A plurality of flow paths 5a through which a refrigerant such as air flows are provided inside the conductive plate 5. The flow paths 5a extend, for example, in directions intersecting (orthogonal to) the stacking direction and the lead-out directions of the positive electrode terminal 6 and the negative electrode terminal 7. In addition to the function of a connecting member for electrically connecting the power storage modules 4 to each other, the conductive plate 5 also functions as a heat sink for dissipating heat generated by the power storage modules 4 by allowing the refrigerant to flow through these flow paths 5a.

[0040] The restraining member 3 is composed of a pair of end plates 8 that sandwich the module stack 2 in the stacking direction, and fastening bolts 9 and nuts 10 that fasten the end plates 8 to each other. An electrically insulating film F is provided on the surface of the end plate 8 on the module stack 2 side, and the film F insulates the end plate 8 from the conductive plate 5.

[0041] Next, the structure of the power storage module 4 will be described in detail. Figure 2 Yes means Figure 1 A schematic cross-sectional view of the internal structure of the power storage module shown. Figure 2 As shown, the power storage module 4 includes an electrode stack 11 and a resin sealing body 12 that seals the electrode stack 11. The power storage module 4 is formed in a rectangular parallelepiped shape, for example.

[0042] The electrode stack 11 includes a plurality of electrodes stacked in a stacking direction D with a separator 13 interposed therebetween and current collectors (metal plates 20A, 20B) located at the stacking ends of the electrode stack 11. The plurality of electrodes include a negative terminal electrode 18, a positive terminal electrode 19, and a plurality of bipolar electrodes 14 stacked between the negative terminal electrode 18 and the positive terminal electrode 19. The stack of the plurality of bipolar electrodes 14 is disposed between the negative terminal electrode 18 and the positive terminal electrode 19.

[0043] The bipolar electrode 14 includes: a metal plate 15 as a current collector, including one surface 15a and another surface 15b provided on the opposite side of the one surface 15a; a positive electrode 16 provided on one surface 15a; and a negative electrode 17 provided on the other surface 15b. One surface 15a is a surface facing one side of the stacking direction D, for example, facing upward in the direction of gravity. The other surface 15b is a surface facing the other side of the stacking direction D, for example, facing downward in the direction of gravity. The positive electrode 16 is a positive electrode active material layer formed by applying a positive electrode active material to the metal plate 15. The negative electrode 17 is a negative electrode active material layer formed by applying a negative electrode active material to the metal plate 15. In the electrode stack 11, the positive electrode 16 of one bipolar electrode 14 faces the negative electrode 17 of the other bipolar electrode 14 adjacent to one side of the stacking direction D via the separator 13. In the electrode stack 11 , the negative electrode 17 of one bipolar electrode 14 faces the positive electrode 16 of another bipolar electrode 14 adjacent in the other direction of the stacking direction D via the separator 13 .

[0044] The negative terminal electrode 18 includes a metal plate 15 and a negative electrode 17 provided on the other surface 15b of the metal plate 15. The negative terminal electrode 18 is arranged on one end side in the stacking direction D so that the other surface 15b faces the center side in the stacking direction D of the electrode stack 11. A metal plate 20A is further stacked on one surface 15a of the metal plate 15 of the negative terminal electrode 18, and is electrically connected to the conductive plate 5 on one side adjacent to the power storage module 4 via the metal plate 20A. The negative electrode 17 provided on the other surface 15b of the metal plate 15 of the negative terminal electrode 18 faces the positive electrode 16 of the bipolar electrode 14 at one end in the stacking direction D via the separator 13.

[0045] The positive terminal electrode 19 includes a metal plate 15 and a positive electrode 16 provided on one surface 15a of the metal plate 15. The positive terminal electrode 19 is arranged on the other end side in the stacking direction D so that the one surface 15a faces the center side in the stacking direction D of the electrode stack 11. A metal plate 20B is further stacked on the other surface 15b of the metal plate 15 of the positive terminal electrode 19, and is electrically connected to the other conductive plate 5 adjacent to the power storage module 4 via the metal plate 20B. The positive electrode 16 provided on one surface 15a of the metal plate 15 of the positive terminal electrode 19 faces the negative electrode 17 of the bipolar electrode 14 at the other end in the stacking direction D via the separator 13.

[0046] The metal plates 15 are made of metal such as Al, SUS, Ni, Cu, etc. Each metal plate 15 is one of the metal plates included in the electrode stack 11. The edge 15c of the metal plate 15 is in a rectangular frame shape, forming an uncoated area 15d (see Figure 3) as a part. As the positive electrode active material constituting the positive electrode 16, for example, an oxide active material can be cited. As the oxide active material, for example, LiCoO 2 、LiMnO 2 、LiNiO 2 、LiVO 2 、LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O 2 Rock salt layered active materials, LiMn 2 O 4 、Li(Ni 0.5 Mn 1.5 ) 4 Spinel active materials, LiFePO 4 、LiMnPO 4 、LiNiPO 4 、LiCuPO 4 Olivine type active materials, etc. As the negative electrode active material constituting the negative electrode 17, for example, carbon active materials, oxide active materials and metal active materials can be cited. In this embodiment, the formation area of ​​the negative electrode 17 on the other side 15b of the metal plate 15 is larger than the formation area of ​​the positive electrode 16 on one side 15a of the metal plate 15. The electrode stack 11 has a plurality of stacked metal plates 15, 20A, 20B.

[0047] The diaphragm 13 is a member for preventing short circuits between the metal plates 15, and is formed into a sheet, for example. As the diaphragm 13, a porous film composed of a polyolefin resin such as polyethylene (PE) and polypropylene (PP), a woven or non-woven fabric composed of polypropylene, methylcellulose, etc., etc. can be exemplified. The diaphragm 13 can be reinforced with a vinylidene fluoride resin compound. It should be noted that the diaphragm 13 is not limited to a sheet, and a bag-shaped diaphragm can also be used.

[0048] The metal plates 20A and 20B are substantially the same members as the metal plate 15, and are made of metals such as Al, SUS, Ni, and Cu, for example. The metal plates 20A and 20B are both one of the metal plates included in the electrode stack 11. The metal plates 20A and 20B are formed into uncoated electrodes in which the positive electrode active material layer and the negative electrode active material layer are not coated on one surface 20a and the other surface 20b. That is, the metal plates 20A and 20B are uncoated electrodes in which the active material layer is not provided on both surfaces.

[0049] The negative terminal electrode 18 is arranged between the metal plate 20A and the bipolar electrode 14 along the stacking direction D by the metal plate 20A. The other surface 20b of the metal plate 20A is in direct contact with the one surface 15a of the metal plate 15 of the negative terminal electrode 18 without any intervening thing in between, thereby being electrically connected. The positive terminal electrode 19 is arranged between the metal plate 20B and the bipolar electrode 14 along the stacking direction D by the metal plate 20B. The one surface 20a of the metal plate 20B is in direct contact with the other surface 15b of the metal plate 15 of the positive terminal electrode 19 without any intervening thing in between, thereby being electrically connected.

[0050] In the electrode stack 11, the central region of the electrode stack 11 (the region where the active material layer is arranged in the bipolar electrode 14, the negative terminal electrode 18, and the positive terminal electrode 19) bulges in the stacking direction D compared with the surrounding region. Therefore, the metal plates 20A and 20B are bent in the direction in which the central regions of the metal plates 20A and 20B are separated from each other. The central regions of one surface 20a of the metal plate 20A and the other surface 20b of the metal plate 20B are in contact with the conductive plate 5.

[0051] The sealing body 12 is formed of, for example, an insulating resin in a rectangular cylindrical shape as a whole. The sealing body 12 is formed, for example, to have a pair of short sides 12a and a pair of long sides 12b (see Figure 3 ) is a rectangular cylindrical shape. The sealing body 12 is provided so as to surround the side surface 11a of the electrode stack 11. The sealing body 12 holds the edge portion 15c on the side surface 11a.

[0052] The sealing body 12 includes a plurality of frame-shaped first sealing portions 21 (resin portions) respectively provided at the edges of the metal plates included in the electrode stack 11 (i.e., the edge 15c of the metal plate 15 and the edge 20c of the metal plates 20A and 20B), and second sealing portions 22 respectively surrounding the first sealing portions 21 from the outside along the side surface 11a and being combined with the first sealing portions 21. The first sealing portion 21 and the second sealing portion 22 are, for example, insulating resins, and as constituent materials of the resin, for example, polypropylene (PP), polyphenylene sulfide (PPS), modified polyphenylene ether (modified PPE), etc. can be cited.

[0053] The first sealing portion 21 is continuously arranged over the entire circumference of the edge 15c of the metal plate 15 and the edge 20c of the metal plates 20A and 20B, and is in a rectangular frame shape when viewed from the stacking direction D. The first sealing portion 21 is airtightly joined to the metal plate 15, and the first sealing portion 21 is airtightly joined to the metal plates 20A and 20B, respectively. When viewed from the stacking direction D, the first sealing portion 21 extends to a position closer to the outside than the edge 15c of the metal plate 15 or the edge 20c of the metal plates 20A and 20B. The first sealing portion 21 includes an outer portion 21a extending outward from the edge of the metal plate 15 or the metal plates 20A and 20B, and an inner portion 21b located at a position closer to the inside than the edge of the metal plate 15 or the metal plates 20A and 20B. A fusion layer 23 is formed at the top end (outer edge) of the outer portion 21a of the first sealing portion 21.

[0054] The plurality of first sealing portions 21 include a plurality of first sealing portions 21A provided on the bipolar electrode 14 and the positive terminal electrode 19 , a first sealing portion 21B provided on the negative terminal electrode 18 , a first sealing portion 21C provided on the metal plate 20A, and first sealing portions 21D and 21E provided on the metal plate 20B.

[0055] The first sealing portion 21A is bonded to one surface 15a of the metal plate 15 of the bipolar electrode 14 and the positive terminal electrode 19. The inner portion 21b of the first sealing portion 21A is located between the edge portions 15c of the metal plates 15 adjacent to each other in the stacking direction D. The region where the edge portion 15c of one surface 15a of the metal plate 15 overlaps with the first sealing portion 21A becomes the bonding region between the metal plate 15 and the first sealing portion 21A.

[0056] In the present embodiment, the first sealing portion 21A is formed into a double-layer structure by folding a film in half. The outer edge of the first sealing portion 21A embedded in the second sealing portion 22 is the folded portion (bend portion) of the film. The first layer of the film constituting the first sealing portion 21A is bonded to one surface 15a. The inner edge of the second layer of the film is located at a position closer to the outside than the inner edge of the first layer of the film, forming a step portion for placing the diaphragm 13. The inner edge of the second layer of the film is located at a position closer to the inside than the edge of the metal plate 15.

[0057] The first sealing portion 21B is bonded to one surface 15a of the metal plate 15 of the negative terminal electrode 18. The inner portion 21b of the first sealing portion 21B is located between the edge 15c of the metal plate 15 of the negative terminal electrode 18 and the edge 20c of the metal plate 20A, which are adjacent to each other in the stacking direction D. The region where the edge 15c of one surface 15a of the metal plate 15 overlaps with the inner portion 21b of the first sealing portion 21B becomes the bonding region between the metal plate 15 and the first sealing portion 21B. The first sealing portion 21B is also bonded to the other surface 20b of the metal plate 20A. The region where the edge 20c of the other surface 20b of the metal plate 20A overlaps with the first sealing portion 21B becomes the bonding region between the metal plate 20A and the first sealing portion 21B. In the present embodiment, the first sealing portion 21B is also bonded to the edge 20c of the other surface 20b of the metal plate 20A.

[0058] The first sealing portion 21C is bonded to one surface 20a (outer surface) of the metal plate 20A. The area where the edge 20c of one surface 20a of the metal plate 20A overlaps with the first sealing portion 21C becomes the bonding area between the metal plate 20A and the first sealing portion 21C. One surface 20a of the metal plate 20A has an exposed surface 20d exposed from the first sealing portion 21C. The conductive plate 5 is arranged in contact with the exposed surface 20d.

[0059] In this embodiment, the outer edges of the first sealing parts 21B and 21C embedded in the second sealing part 22 are continuous with each other. That is, the first sealing parts 21B and 21C are formed by folding a film in half across the edge 20c of the metal plate 20A. The outer edges of the first sealing parts 21B and 21C are the folded back parts of the film. The film constituting the first sealing parts 21B and 21C is joined to the edge 20c at both the one surface 20a and the other surface 20b of the metal plate 20A.

[0060] The first sealing portion 21D is bonded to one surface 20a of the metal plate 20B. The inner portion 21b of the first sealing portion 21D is located between the edge 15c of the metal plate 15 of the positive terminal electrode 19 and the edge 20c of the metal plate 20B, which are adjacent to each other in the stacking direction D. The region where the edge 20c of one surface 20a of the metal plate 20B overlaps with the first sealing portion 21D becomes the bonding region between the metal plate 20B and the first sealing portion 21D.

[0061] The first sealing portion 21E is arranged at the edge 20c of the other surface 20b (outer surface) of the metal plate 20B. In the present embodiment, the first sealing portion 21E is not bonded to the metal plate 20B. The other surface 20b of the metal plate 20B has an exposed surface 20d exposed from the first sealing portion 21E. The conductive plate 5 is arranged in contact with the exposed surface 20d.

[0062] In this embodiment, the outer edges of the first sealing parts 21D and 21E embedded in the second sealing part 22 are continuous with each other. That is, the first sealing parts 21D and 21E are formed by folding a film in half across the edge 20c of the metal plate 20B. The outer edges of the first sealing parts 21D and 21E are the folded back parts of the film. The film constituting the first sealing parts 21D and 21E is joined to the edge 20c on one surface 20a of the metal plate 20B.

[0063] A plurality of internal spaces V are provided in the electrode stack 11. Each internal space V is provided between adjacent metal plates. The internal space V is a space between adjacent metal plates in the stacking direction D, which is separated airtightly and liquid-tightly by the metal plates and the sealing body 12. The internal space V contains, for example, an electrolyte (not shown). The electrolyte contains, for example, a non-aqueous solvent and a supporting salt. Examples of the non-aqueous solvent include organic solvents such as carbonates, ethers, esters, nitriles, sulfones, and lactones. Examples of the supporting salt include LiPF 6 The electrolyte is impregnated in the separator 13 , the positive electrode 16 , and the negative electrode 17 .

[0064] Figure 3 yes Figure 2 A cross-sectional view of the power storage module shown in FIG. Figure 3 As shown, a liquid injection port P is provided at a short side portion 12a of one side of the sealing body 12. The liquid injection port P penetrates the sealing body 12 along the long side direction of the sealing body 12. The liquid injection port P is connected to the internal space V and the external space. The position where the liquid injection port P is provided at the short side portion 12a of one side of the sealing body 12 is determined according to the stacking direction D of the corresponding internal space V (refer to Figure 2 ) position. The injection port P is located in the stacking direction D (refer to Figure 2 ) so that the adjacent injection ports P do not overlap each other and are staggered in the short side direction of the sealing body 12. Figure 3 In the example, the liquid injection port P is provided at one end portion of the short side portion 12 a of the sealing body 12 .

[0065] The shape of the inner region sealed by the sealing body 12 when viewed from the stacking direction (i.e. Figure 3 The shape of the interface between the internal space V and the sealing body 12 shown in the figure is rectangular. It should be noted that the shape of the internal area sealed by the sealing body 12 is not limited to a rectangular shape, and can also be a quadrilateral shape, a polygonal shape other than a quadrilateral, etc. In addition, the corners in the polygonal shape can also be a shape with rounded corners.

[0066] exist Figure 3In the figure, in the internal area (rectangular area) sealed by the sealing body 12, the injection port P is formed only in the sealing body 120 in the area facing one side of the rectangle. However, the injection port P may also be provided at multiple locations, for example, the internal area sealed by the sealing body 12 is polygonal, and the injection port P is formed in a total of two or more sealing bodies 120 in the area facing two or more sides of the polygon.

[0067] The positive electrode 16 includes a plurality of divided regions 16a divided by grooves 16A and 16B on one surface 15a of the metal plate 15. When the surface of the inner space V side of the side where the injection port P is formed in the sealing body 12 is set as the injection port side surface 150P, the grooves 16A and 16B extend from one side of the injection port side surface 150P toward the direction opposite to the injection port side surface 150P ( Figure 3 Therefore, in Figure 3 In the embodiment, the grooves 16A and 16B extend along the longitudinal direction of one surface 15a. The bottom surfaces of the grooves 16A and 16B are formed by the one surface 15a.

[0068] It should be noted that the side of the sealing body 12 where the liquid injection port P is formed means the side where the liquid injection port P is formed when the electrode stack 11 is viewed from the stacking direction.

[0069] The plurality of segmented regions 16a are arranged to be separated from each other in the short side direction of one surface 15a. In the present embodiment, the positive electrode 16 is divided into six segmented regions 16a by five grooves 16A and 16B. The plurality of segmented regions 16a have a rectangular shape with the long side direction of one surface 15a as the long side direction and the short side direction of one surface 15a as the short side direction.

[0070] An uncoated area 150 in which the positive electrode 16 is not formed is provided around the plurality of segmented areas 16a on one surface 15a of the metal plate 15. The uncoated area 150 includes: an uncoated area 150A provided in an area facing the side surface 150P of the liquid injection port; an uncoated area 150B provided on the side opposite to the uncoated area 150A across the plurality of segmented areas 16a; and an uncoated area 150C provided in an area between the uncoated area 150A and the uncoated area 150B and outside the plurality of segmented areas 16a. It should be noted that the internal space V is formed by the grooves 16A, 16B and the uncoated area 150.

[0071] Although not shown in the figure, the negative electrode 17 also includes a plurality of divided regions divided by grooves, similarly to the positive electrode 16. Figure 2 ) when observed, the grooves of the negative electrode 17 are arranged to overlap with the grooves 16A and 16B of the positive electrode 16. In addition, an uncoated area is also provided around the negative electrode 17 divided into a plurality of divided areas.

[0072] When the electrolyte is injected into the internal space V, the gap formed by the grooves of the positive electrode 16 and the grooves of the negative electrode 17 functions as a flow path for the electrolyte, similarly to the gap between the uncoated area 150 of one surface 15a and the uncoated area of ​​the other surface 15b.

[0073] Among the plurality of grooves, there are grooves 16A and 16B having different widths. The width of the groove 16A [d A ] is set to be larger than the width of the groove 16B [d B ] Large width. Figure 3 , a mode having one groove 16A and four grooves 16B is shown, but the present invention is not limited thereto, and two or more grooves 16A having a large width may be provided. It should be noted that the grooves 16B may have, for example, the same shape as each other. Figure 3 In contrast, in the case of a plurality of grooves 16A having a large width, the grooves 16A also have shapes equal to each other, for example. Figure 3 In the embodiment, the shapes of the grooves 16A and 16B (and the directions in which the grooves 16A and 16B extend ( Figure 3 The shape of the cross section (in the Y direction) perpendicular to the direction of the Y axis) is rectangular. It should be noted that the shapes of the grooves 16A and 16B are not particularly limited, and may be, for example, square, rectangular, triangular, trapezoidal, etc. Figure 3 The shape of the grooves 16A and 16B in the extending direction (the shape when looking down at the grooves 16A and 16B) is a straight line. It should be noted that the shape of the grooves 16A and 16B in the extending direction is not particularly limited, and may be, for example, wavy, broken line, lattice, etc.

[0074] Here, the previous battery is described. In the previous battery, from the viewpoint of increasing the battery capacity, it was studied to reduce the volume of the uncoated area on the collector where the active material layer is not formed. However, sometimes it is difficult for the electrolyte to penetrate the grooves arranged between the multiple active material layers in order to make the electrolyte penetrate. This is believed to be because, due to the reduction in the volume of the uncoated area, the penetration path of the electrolyte becomes narrower, and the amount of electrolyte per unit time is reduced, so it takes time for the electrolyte to spread throughout the entire internal space.

[0075] In contrast, in the embodiment of the present disclosure, there are grooves 16A and 16B having different widths, and the width of the groove 16A [d A ] is set to be larger than the width of the groove 16B [d B] large width. Therefore, after the electrolyte initially penetrates into the uncoated area 150A from the injection port P in the internal space, the electrolyte is also quickly supplied to the uncoated area 150B through the wide groove 16A. Then, the electrolyte that has penetrated into the uncoated area 150B also penetrates into the narrow groove 16B from the side of the uncoated area 150B, and the electrolyte is easily distributed throughout the entire internal space V. As a result, the time required for the electrolyte to penetrate the entire electrode stack 11 in the manufacture of the battery is shortened. In addition, it is also possible to suppress the occurrence of defects in which the electrolyte is not completely distributed throughout the entire active material layer after the injection of the electrolyte is completed.

[0076] Here, the formation position of the wide groove 16A is described. From the viewpoint that the electrolyte easily spreads throughout the internal space V when the electrolyte is injected, the wide groove 16A is preferably provided at a position that satisfies at least one of the following requirements (A1) and (A2).

[0077] (A1) The groove 16A is provided at a position closest to the liquid injection port P among the plurality of grooves 16A and 16B.

[0078] (A2) The groove 16A is provided at a position closest to the position of the groove provided at the end (for example, at the end of the groove 16A and the groove 16B) in the direction in which the grooves 16A and 16B are arranged. Figure 3 The leftmost groove in the middle) and the groove provided at the end on the opposite side (for example, Figure 3 The rightmost slot in the

[0079] exist Figure 3 In the embodiment, groove 16A is provided at a position satisfying the requirement of (A2).

[0080] In addition, when there are a plurality of wide grooves 16A, it is preferable that at least one of the grooves 16A satisfies at least one of the requirements (A1) and (A2) described above.

[0081] The width of the groove 16B [d B ] relative to the width of the groove 16A [d A ] ratio ([d B ] / [d A ]) is preferably 0.07 or more and 0.40 or less, and more preferably 0.10 or more and 0.30 or less. B ] / [d A ] is greater than the above lower limit, so that the electrolyte can easily spread throughout the entire internal space V when the electrolyte is injected. B ] / [d A ] is below the above-mentioned upper limit value, thereby making it easy to increase the battery capacity, which is preferred in this regard.

[0082] The width of the groove 16A [dA ] is preferably 5.0 mm or more and 15.0 mm or less, and more preferably 7.0 mm or more and 10.0 mm or less. A ] is greater than the above lower limit, so that the electrolyte can easily spread throughout the entire internal space V when the electrolyte is injected. A ] is below the above-mentioned upper limit value, thereby making it easy to increase the battery capacity, which is preferred in this regard.

[0083] The width of the groove 16B [d B ] is preferably 0.5 mm or more and 4.0 mm or less, and more preferably 1.0 mm or more and 3.0 mm or less. B ] is greater than the above lower limit, so that the electrolyte can easily spread throughout the entire internal space V when the electrolyte is injected. B ] is below the above-mentioned upper limit value, thereby making it easy to increase the battery capacity, which is preferred in this regard.

[0084] The width of the groove 16A [d A ] and the width of the groove 16B [d B ] refers to the dimension of the groove in the direction perpendicular to the direction in which each groove extends. Regarding the measurement of the width in the groove, the dimension (length) of the groove in the direction perpendicular to the direction in which the groove extends when looking down at the groove is measured at any 5 locations, and the arithmetic mean value is set.

[0085] In the above-mentioned embodiment, the mode in which the active material layers of both the positive electrode 16 and the negative electrode 17 have grooves is described. However, it is not limited to this, and the grooves may be formed only in the positive electrode active material layer or only in the negative electrode active material layer. It should be noted that from the viewpoint of suppressing the precipitation of lithium, the grooves are preferably formed only in the positive electrode active material layer.

[0086] The size of the electrode stack in the battery according to the embodiment of the present disclosure is not particularly limited, and the area of ​​the electrode stack when viewed in the stacking direction of the electrode stack can be, for example, 0.5 m 2 In addition, the upper limit of the area of ​​the electrode stack can be set to 4.0 m 2 the following.

[0087] It should be noted that the configuration of the present disclosure is not limited to the above-described embodiment, and the configuration can be appropriately changed as long as the problem can be solved.

[0088] Next, the effect of the battery according to the embodiment of the present disclosure was confirmed by a simulation experiment.

[0089] (Example 1, Comparative Example 1)

[0090] For Figure 3The structure shown in FIG. 1 is a simulation of an electrode stack having an active material layer on one surface of a metal plate as a current collector, an active material layer having a segmented area segmented by a groove, and an uncoated area around the active material layer where the active material layer is not provided. The shape of the cross section in the groove and the uncoated area is set to a rectangle. Among them, the number of grooves is set to 14, the two central grooves are set to "groove A", and the remaining 12 grooves (6 grooves are set on one side and 6 grooves are set on the other side relative to the two grooves A) are set to "groove B".

[0091] In the groove A, groove B, and the inner region sealed by the sealing body, an uncoated region A ( Figure 3 The uncoated region 150A in the middle), the uncoated region B ( Figure 3 The uncoated region 150B in the middle), and the uncoated region C ( Figure 3 The "width" in the uncoated area 150C) is shown in Table 1.

[0092] As a simulation experiment, the time required for the electrolyte solution to completely permeate the entire electrode stack (permeation time) was calculated. The results are shown in Table 1.

[0093] 【surface

[0094]

[0095] As shown in Table 1, it can be seen that in Example 1, which satisfies the requirement that the width of groove A is larger than the width of groove B, the time required for the electrolyte to penetrate the entire electrode stack can be shortened compared to Comparative Example 1, which does not satisfy this requirement. It can be seen that in Example 1, a battery with improved permeability of the electrolyte to the active material layer is obtained.

Claims

1. A battery having: An electrode stack, comprising a stack of electrodes including a current collector and an active material layer, wherein the active material layer is provided on one or both surfaces of the current collector, and the active material layer is divided into a plurality of regions by providing a plurality of grooves between the active material layers; A sealing body, which forms an internal space for accommodating an electrolyte between adjacent current collectors and seals the internal space; as well as A liquid injection port is formed in the sealing body to connect the internal space with the outside. The inner space is formed by the groove and an uncoated area around the active material layer where the active material layer is not provided. The inner region sealed by the sealing body is polygonal in shape when viewed from the stacking direction of the electrode stack. When the surface of the sealing body on the inner space side where the liquid injection port is formed is set as the liquid injection port side surface, The groove extends between the active material layers from the side surface of the liquid injection port toward a direction opposite to the side surface of the liquid injection port. The plurality of grooves include at least a groove A and a groove B having different widths, and the width of the groove A is greater than the width of the groove B.

2. The battery according to claim 1, The inner region sealed by the sealing body is a quadrilateral when viewed from the stacking direction of the electrode stack. The sealing body has the liquid injection port only in a region facing one side of the quadrilateral.

3. The battery according to claim 1, At least one of the slots A satisfies at least one of the following requirements A1 and A2: A1: The position closest to the liquid injection port among the plurality of grooves A2: In the direction in which the plurality of grooves are arranged, the groove is provided at a position closest to a position that is equidistant from a groove provided at the end and a groove provided at an end on the opposite side.

4. The battery according to claim 1, The width d of the groove B B Relative to the width d of the slot A A The ratio of B / d A It is 0.07 or more and 0.40 or less.

5. The battery according to claim 1, The width d of the groove B B It is not less than 0.5 mm and not more than 4.0 mm.

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