Battery

Abstract

A battery includes: an electrode stack including a stack of electrodes, each of which includes a current collector and an active material layer divided with a channel therebetween; a sealing body formed between the current collectors in an internal space accommodating the electrolyte and sealing the internal space; and an injection port formed in the sealing body and communicating an internal space with the outside, in which the internal space is formed by the channel and an uncoated region in which the active material layer is not provided around the active material layer, the internal region sealed by the sealing body having a polygonal shape when viewed from a stacking direction of the electrode stack, a channel extending from the injection port side in an opposite direction to the injection port side between the divided regions of the active material layer; and a cross-sectional area [a] of a region facing a surface in which the injection port is formed in the uncoated region is larger than a cross-sectional area [d] of the channel.

Description

Technical Field

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

[0002] As a conventional battery manufacturing method, there is known a manufacturing method including a step of injecting an electrolyte into a space spanning a separator and between electrodes disposed opposite to each other (eg, Japanese Patent Application Laid-Open (JP-A) No. 2013-191450).

[0003] Further, JP-A No. 2022-188536 discloses a method for manufacturing a bipolar storage device, comprising: a first decompression step, reducing the pressure of the internal space of the battery to a first pressure when the electrolyte is allowed to penetrate the internal space; a first injection step, injecting a predetermined amount of electrolyte from a holding unit holding a predetermined amount of electrolyte through an injection port into the internal space whose pressure is reduced in the first decompression step; a second decompression step, reducing the pressure of the internal space into which the predetermined amount of electrolyte is injected to a second pressure through the holding unit and the injection port, so that a portion of the electrolyte flows back from the internal space to the holding unit; and a second injection step, increasing the pressure in the holding unit holding the refluxed electrolyte to a pressure higher than the second pressure, and injecting the electrolyte into the internal space from the holding unit through the injection port, wherein the second decompression step includes an initial decompression step of reducing the pressure of the internal space at a decompression rate lower than the decompression rate in the first decompression step. Summary of the invention

[0005] In this regard, in conventional batteries, from the perspective of increasing battery capacity, it is considered to reduce the volume (width) of the uncoated area on the current collector where the active material layer is not formed. However, there is a problem that if the width of the uncoated area is reduced too much, the fluidity of the electrolyte in the channel provided in the active material layer will deteriorate.

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

[0007] Means for solving the above-mentioned problems include the following aspects. The battery of the first aspect of the present disclosure comprises: An electrode stack comprising a stack of electrodes, each electrode in the stack of electrodes comprising a current collector and an active material layer, the active material layer being disposed on one or both surfaces of the current collector, and the active material layer being divided into a plurality of regions having channels therebetween; a sealing body that forms an internal space containing an electrolyte between adjacent current collectors and seals the internal space; and an injection port, which is formed in the sealing body and communicates the internal space with the outside, in, The inner space is formed by the channel and the uncoated area around the active material layer where the active material layer is not disposed. When viewed from the stacking direction of the electrode stack, the inner region sealed by the sealing body has a polygonal shape, and When the surface of the sealing body on the inner space side of the side forming the injection port is referred to as the injection port side surface, The channel extends from one side of the injection port side surface in a direction opposite to the injection port side surface between divided regions of the active material layer; and The cross-sectional area [a] of the region facing the injection port side surface in the uncoated region in a cross section perpendicular to the direction in which the injection port side surface extends is larger than the cross-sectional area [d] of the channel in a cross section perpendicular to the direction in which the channel extends. A battery according to a second aspect of the present disclosure is the battery according to the first aspect, wherein: When viewed from the stacking direction of the electrode stack, the inner region sealed by the sealing body has a quadrilateral shape, and The battery has an injection port only in a region of the sealing body facing one side of the quadrilateral shape. A battery according to a third aspect of the present disclosure is the battery of the first aspect or the second aspect, wherein a ratio ([d] / [a]) of a cross-sectional area [d] of the channel to a cross-sectional area [a] of the uncoated region is 0.1 to 0.9. The battery according to the fourth aspect of the present disclosure is the battery according to any one of the first to third aspects, wherein the cross-sectional area [d] of the channel is 0.4 mm 2 Up to 2.0mm 2 . A battery according to a fifth aspect of the present disclosure is a battery according to any one of the first to fourth aspects, wherein when viewed from the stacking direction of the electrode stack, the area of ​​the electrode stack is 0.5 m 2 above.

[0008] According to the present disclosure, there is provided a battery having improved ability of an electrolyte to penetrate into an active material layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 is a schematic cross-sectional view showing a configuration of a bipolar power storage device according to an embodiment; Figure 2 It is shown Figure 1 A schematic cross-sectional view of the internal configuration of the power storage module shown in ; and Figure 3 is with Figure 2 is a cross-sectional view perpendicular to the stacking direction of the power storage modules shown in . DETAILED DESCRIPTION

[0010] The battery according to the embodiment of the present disclosure will be described below with reference to the accompanying drawings. In the description of the drawings, the same or similar elements use the same reference symbols, and redundant descriptions will be omitted.

[0011] Figure 1 is a schematic cross-sectional view showing a configuration of a bipolar power storage device according to an embodiment. Figure 1 The bipolar power storage device 1 shown in (hereinafter referred to as "power storage device 1") is a device for batteries of various types of vehicles such as forklifts, hybrid electric vehicles, and battery electric vehicles. The power storage device 1 is a secondary battery such as, for example, 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 will be taken as an example. 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.

[0012] The module stack 2 includes power storage modules 4 and conductive plates 5 stacked and arranged 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 have a rectangular shape as viewed in the stacking direction.

[0013] The storage modules 4 adjacent to each other in the stacking direction are electrically interconnected via the conductive plates 5. The conductive plates 5 are provided between the storage modules 4 adjacent to each other in the stacking direction, and are provided on the outer sides of the storage modules 4 located at the stacking end. The positive terminal 6 is connected to one of the conductive plates 5 provided on the outer sides of the storage modules 4 located at the stacking end. The negative terminal 7 is connected to the other of the conductive plates 5 provided on the outer sides of the storage modules 4 located at the stacking end. The positive terminal 6 and the negative terminal 7 are drawn out from the edge portions of the conductive plates 5 in a direction intersecting the stacking direction, for example. Charging and discharging of the storage device 1 are implemented through the positive terminal 6 and the negative terminal 7.

[0014] A plurality of flow paths 5a for circulating a coolant such as air are provided inside the conductive plate 5. The flow paths 5a extend, for example, in a direction intersecting (orthogonal to) the stacking direction and the lead-out direction of the positive terminal 6 and the negative terminal 7. The conductive plate 5 has both a function as a connection member for electrically interconnecting the storage modules 4 and a function as a radiator for dissipating heat generated by the storage modules 4 by circulating a coolant through the flow paths 5a.

[0015] The restraining member 3 is composed of a pair of end plates 8 that clamp the module stack 2 in the stacking direction, and fastening bolts 9 and nuts 10 that fasten the pair of end plates 8 together. The surface of the end plate 8 on the module stack 2 side is provided with a film F having an electrical insulating property, and the film F insulates the end plate 8 from the conductive plate 5 from each other.

[0016] Next, the configuration of the power storage module 4 will be described in detail. Figure 2 It is shown Figure 1 Schematic cross-sectional view of the internal configuration of the power storage module shown in FIG. Figure 2 As shown in FIG. 1 , the power storage module 4 includes an electrode stack 11 and a sealing body 12 made of resin that seals the electrode stack 11. The power storage module 4 is formed in a rectangular parallelepiped shape, for example.

[0017] The electrode stack 11 includes a plurality of electrodes stacked along a stacking direction D via a separator 13, 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.

[0018] The bipolar electrodes 14 each have a metal plate 15 as a current collector, and include a surface 15a and another surface 15b disposed on the opposite side of the surface 15a, a positive electrode 16 disposed on the surface 15a, and a negative electrode 17 disposed on the other surface 15b. The surface 15a is a surface facing one side in the stacking direction D and, for example, facing upward in the direction of gravity. The other surface 15b is a surface facing the other side in the stacking direction D and, for example, facing downward in the direction of gravity. The positive electrode 16 is a positive electrode active material layer formed by coating the metal plate 15 with a positive electrode active material. The negative electrode 17 is a negative electrode active material layer formed by coating the metal plate 15 with a negative electrode active material. The positive electrode 16 of one bipolar electrode 14 in the electrode stack 11 is opposite to the negative electrode 17 of another bipolar electrode 14 adjacent to it on one side in the stacking direction D across the separator 13. The negative electrode 17 of one bipolar electrode 14 in the electrode stack 11 is opposed to the positive electrode 16 of the other bipolar electrode 14 adjacent thereto on the other side in the stacking direction D across the separator 13 .

[0019] The negative terminal electrode 18 has 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 provided on one end side in the stacking direction D so that the other surface 15b faces the center side of the electrode stack 11 in the stacking direction D. A metal plate 20A is also stacked on one surface 15a of the metal plate 15 of the negative terminal electrode 18, and the negative terminal electrode 18 is electrically connected to one of the conductive plates 15 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 is opposite to the positive electrode 16 of the bipolar electrode 14 on one end in the stacking direction D via the separator 13.

[0020] The positive terminal electrode 19 has 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 provided on the other end side in the stacking direction D so that the one surface 15a faces the center side of the electrode stack 11 in the stacking direction D. A metal plate 20B is also stacked on the other surface 15b of the metal plate 15 of the positive terminal electrode 19, and the positive terminal electrode 19 is electrically connected to another conductive plate 5 adjacent to the storage module 4 among the conductive plates 5 via the metal plate 20B. The positive electrode 16 provided on the one surface 15a of the metal plate 15 of the positive terminal electrode 19 is opposite to the negative electrode 17 of the bipolar electrode 14 on the other end in the stacking direction D via the separator 13.

[0021] The metal plates 15 include a metal such as, for example, Al, SUS, Ni, or Cu. Each of the metal plates 15 is one of the metal plates included in the electrode stack 11. The edge portion 15c of the metal plate 15 forms an uncoated region 150 (see FIG. 1 ) having a rectangular frame shape and not coated with the positive electrode active material and the negative electrode active material. Figure 3 ) part. Examples of the positive electrode active material constituting the positive electrode 16 include oxide active materials. Examples of oxide active materials include LiCoO2, LiMnO2, LiNiO2, LiVO2, LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2 rock salt layered active materials such as LiMn2O4 and Li(Ni 0.5 Mn 1.5 )O4 spinel active materials, and olivine active materials such as LiFePO4, LiMnPO4, LiNiPO4 and LiCuPO4. Examples of negative electrode active materials constituting the negative electrode 17 include carbon active materials, oxide active materials and metal active materials. In the present embodiment, the size of the area where the negative electrode 17 is formed on the other surface 15b of the metal plate 15 is larger than the area where the positive electrode 16 is formed on one surface 15a of the metal plate 15. The electrode stack 11 has a plurality of stacked metal plates 15, 20A, 20B.

[0022] The separator 13 is a member for preventing a short circuit between the metal plates 15, and is formed into a sheet shape, for example. Examples of the separator 13 include a porous film containing a polyolefin resin such as polyethylene (PE) and polypropylene (PP) and a woven or non-woven fabric containing polypropylene or methylcellulose. The separator 13 may be reinforced with a polyvinylidene fluoride resin compound. It will be noted that the separator 13 is not limited to a sheet shape, and a pocket separator may also be used.

[0023] The metal plates 20A, 20B are members substantially the same as the metal plate 15, and include a metal such as, for example, Al, SUS, Ni, or Cu. The metal plates 20A, 20B are each one of the metal plates included in the electrode stack 11. The metal plates 20A, 20B form an uncoated electrode whose one surface 20a and the other surface 20b are not coated with a positive electrode active material layer or a negative electrode active material layer. That is, the metal plates 20A, 20B are uncoated electrodes without an active material layer on both surfaces.

[0024] Due to the metal plate 20A, the negative terminal electrode 18 is disposed between the metal plate 20A and the bipolar electrode 14 along the stacking direction D. The other surface 20b of the metal plate 20A and the one surface 15a of the metal plate 15 of the negative terminal electrode 18 are electrically connected by direct contact without anything therebetween. Due to the metal plate 20B, the positive terminal electrode 19 is disposed between the metal plate 20B and the bipolar electrode 14 along the stacking direction D. The one surface 20a of the metal plate 20B and the other surface 15b of the metal plate 15 of the positive terminal electrode 19 are electrically connected by direct contact without anything therebetween.

[0025] In the electrode stack 11, the central region of the electrode stack 11 (the region where the active material layer is provided in the bipolar electrode 14, the negative terminal electrode 18, and the positive terminal electrode 19) is raised in the stacking direction D compared with the surrounding region. Therefore, the metal plates 20A, 20B are bent in a direction that makes the central regions of the metal plates 20A, 20B have a greater distance 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.

[0026] The sealing body 12 is formed of insulating resin in a rectangular tube shape as a whole. The sealing body 12 is formed to have a pair of short side portions 12a and a pair of long side portions 12b (see FIG. Figure 3 ). Sealing body 12 is provided to surround side surface 11a of electrode stack 11. Sealing body 12 holds edge portion 15c at side surface 11a.

[0027] The sealing body 12 has: a plurality of first sealing portions 21 (resin portions) which are frame-shaped and are provided on edge portions of metal plates included in the electrode stack 11 (i.e., edge portions 15c of the metal plate 15 and edge portions 20c of the metal plates 20A, 20B); and second sealing portions 22 which surround the first sealing portions 21 from the outside along the side surface 11a and are bonded to each of the first sealing portions 21. The first sealing portions 21 and the second sealing portions 22 are, for example, insulating resins, examples of constituent materials of which include polypropylene (PP), polyphenylene sulfide (PPS), and modified polyphenylene ether (modified PPE).

[0028] The first sealing portion 21 is continuously arranged around the entire periphery of the edge portion 15c of the metal plate 15 and the edge portion 20c of the metal plates 20A and 20B, and has a rectangular frame shape when viewed from the stacking direction D. The first sealing portion 21 and the metal plate 15, as well as the first sealing portion 21 and the metal plates 20A and 20B, are all airtightly joined together. When viewed from the stacking direction D, the first sealing portion 21 extends outward beyond the edge portion 15c of the metal plate 15 or the edge portion 20c of the metal plates 20A and 20B. The first sealing portion 21 has an outer portion 21a extending beyond the edge of the metal plate 15 or the metal plates 20A and 20B and an inner portion 21b located inside the edge of the metal plate 15 or the metal plates 20A and 20B. The welding layer 23 is formed on the distal end portion (outer edge portion) of the outer portion 21a of the first sealing portion 21.

[0029] 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.

[0030] The first sealing portion 21A is bonded to a surface 15a of the metal plate 15 of the bipolar electrode 14 and the positive terminal electrode 19. An inner portion 21b of the first sealing portion 21A is located between 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 a surface 15a of the metal plate 15 overlaps with the first sealing portion 21A is the region where the metal plate 15 is bonded to the first sealing portion 21A.

[0031] In the present embodiment, the first sealing portion 21A is formed into a double-layer structure by folding a single-layer film into two layers. The outer edge portion of the first sealing portion 21A embedded in the second sealing portion 22 is the folded back portion (bent portion) of the film. The first layer of the film constituting the first sealing portion 21A is bonded to a surface 15a. The inner edge of the second layer of the film is located outside the inner edge of the first layer of the film to form a step portion on which the diaphragm 13 is placed. The inner edge of the second layer of the film is located inside the edge of the metal plate 15.

[0032] The first sealing portion 21B is joined 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 portion 15c of the metal plate 15 of the negative terminal electrode 18 and the edge portion 20c of the metal plate 20A, which are adjacent to each other in the stacking direction D. The area where the edge portion 15c of one surface 15a of the metal plate 15 overlaps with the inner portion 21b of the first sealing portion 21B is the area where the metal plate 15 is joined to the first sealing portion 21B. The first sealing portion 21B is also joined to the other surface 20b of the metal plate 20A. The area where the edge portion 20c of the other surface 20b of the metal plate 20A overlaps with the first sealing portion 21B is the area where the metal plate 20A is joined to the first sealing portion 21B. In the present embodiment, the first sealing portion 21B is also joined to the edge portion 20c of the other surface 20b of the metal plate 20A.

[0033] The first sealing portion 21C is bonded to a surface 20a (outer surface) of the metal plate 20A. The region where the edge portion 20c of the surface 20a of the metal plate 20A overlaps with the first sealing portion 21C is the region where the metal plate 20A is bonded to the first sealing portion 21C. The 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 to contact the exposed surface 20d.

[0034] In the present embodiment, the outer edge portions of the first seal portions 21B, 21C embedded in the second seal portion 22 are continuous with each other. That is, the first seal portions 21B, 21C are formed by folding a single-layer film into two layers to sandwich the edge portion 20c of the metal plate 20A. The outer edge portions of the first seal portions 21B, 21C are folded back portions of the film. The film constituting the first seal portions 21B, 21C is joined to the edge portion 20c at both one surface 20a and the other surface 20b of the metal plate 20A.

[0035] 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 portion 15c of the metal plate 15 of the positive terminal electrode 19 and the edge portion 20c of the metal plate 20B adjacent to each other in the stacking direction D. The region where the edge portion 20c of one surface 20a of the metal plate 20B overlaps with the first sealing portion 21D is the region where the metal plate 20B is bonded to the first sealing portion 21D.

[0036] The first sealing portion 21E is provided on the edge portion 20c of the other surface 20b (outer surface) of the metal plate 20B. In the present embodiment, the first sealing portion 21E is not joined 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 provided to contact the exposed surface 20d.

[0037] In this embodiment, the outer edge portions of the first seals 21D, 21E embedded in the second seal 22 are continuous with each other. That is, the first seals 21D, 21E are formed by folding a single-layer film into two layers to sandwich the edge portion 20c of the metal plate 20B. The outer edge portions of the first seals 21D, 21E are folded back portions of the film. The film constituting the first seals 21D, 21E is joined to the edge portion 20c at one surface 20a of the metal plate 20B.

[0038] A plurality of internal spaces V are provided inside the electrode stack 11. Each of the internal spaces 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 seal 12. An electrolyte (not shown in the figure) is maintained in the internal space V. The electrolyte includes, for example, a non-aqueous solvent and a carrier salt. Examples of non-aqueous solvents may include organic solvents such as carbonates, ethers, esters, nitriles, sulfones, and lactones. Examples of carrier salts may include lithium salts such as LiPF6. The electrolyte is impregnated into the diaphragm 13, the positive electrode 16, and the negative electrode 17.

[0039] Figure 3 is with Figure 2 A cross-sectional view orthogonal to the stacking direction of the power storage module shown in FIG. Figure 3 As shown in FIG. 1 , an injection port P is provided in one of the short side portions 12a of the sealing body 12. The injection port P penetrates the sealing body 12 in the long side direction of the sealing body 12. The injection port P connects the internal space V with the external space. The position where the injection port P is provided in one of the short side portions 12a of the sealing body 12 depends on the position of the corresponding internal space V in the stacking direction D (see FIG. 1 ). Figure 2 The injection port P is staggered in the short side direction of the sealing body 12 so that in the stacking direction D (see Figure 2 ) The adjacent injection ports P do not overlap. Figure 3 In the example shown in FIG. 1 , the injection port P is provided in one end portion of one short side portion 12 a of the sealing body 12 .

[0040] The shape of the inner area sealed by the sealing body 12 when viewed from the stacking direction (i.e. Figure 3 The shape of the interface between each internal space V and the sealing body 12 shown in FIG is a rectangle. It should be noted that the shape of the internal area sealed by the sealing body 12 is not limited to a rectangle, and may also be a quadrilateral or a polygonal shape other than a quadrilateral. Further, the corners of the polygonal shape may be arc-shaped.

[0041] exist Figure 3In the embodiment, in the inner region (rectangular region) sealed by the sealing body 12, the injection port P is formed only in the region facing one side of the rectangle of the sealing body 12. However, the injection port P may be provided in a plurality of places; for example, the inner region sealed by the sealing body 12 may have a polygonal shape, and a total of two or more injection ports P may be formed in the regions of the sealing body 12 facing two or more sides of the polygonal shape.

[0042] Each positive electrode 16 includes a plurality of divided regions 16a divided by channels 16b on one surface 15a of the metal plate 15. When the surface on the inner space V side of the side where the injection port P is formed of the sealing body 12 is referred to as an injection port side surface 150P, the channels 16b extend from one side of the injection port side surface 150P in the opposite direction of the injection port side surface 150P ( Figure 3 Therefore, in Figure 3 In the embodiment, the channel 16b extends along the long side direction of the one surface 15a. The bottom surface of the channel 16b is formed by the one surface 15a. It will be noted that “the side of the sealing body 12 where the injection port P is formed” refers to the side where the injection port P is formed when the electrode stack 11 is viewed from the stacking direction.

[0043] The plurality of divided regions 16a are spaced apart from each other in the short side direction of the one surface 15a. In the present embodiment, the positive electrode 16 is divided into six divided regions 16a by five channels 16b respectively. The plurality of divided regions 16a have a rectangular shape whose long side direction coincides with the long side direction of the one surface 15a and whose short side direction coincides with the short side direction of the one surface 15a.

[0044] The plurality of trenches 16b have, for example, shapes identical to each other. Figure 3 In the embodiment, the shape of the channel 16b (the direction in which the channel 16b extends ( Figure 3 The shape of the cross section (orthogonal to the Y direction in the direction of the Y axis) is a rectangle. It should be noted that the shape of the channel 16b is not particularly limited, and may be, for example, a square, rectangle, triangle or trapezoid. Figure 3 In the embodiment, the shape of the channel 16b in the direction in which the channel 16b extends (the shape of the channel 16b when the channel 16b is viewed in a top view) is linear. It should be noted that the shape of the channel 16b in the direction in which the channel 16b extends is not particularly limited, and may be, for example, wavy, zigzag, or grid-shaped.

[0045] An uncoated area 150 in which the positive electrode 16 is not formed is provided around a plurality of divided 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 injection port side surface 150P, an uncoated area 150B provided on the opposite side of the uncoated area 150A across the plurality of divided areas 16a, and an uncoated area 150C provided between the uncoated area 150A and the uncoated area 150B on the outside of the plurality of divided areas 16a. It will be noted that the internal space V is formed by the channel 16b and the uncoated area 150.

[0046] Although not shown in the drawings, the negative electrodes 17 also each include a plurality of divided regions divided by channels in the same manner as the positive electrodes 16. The channels in the negative electrodes 17 are arranged to overlap with the channels 16b in the positive electrodes 16 as viewed in the stacking direction D (see FIG. Figure 2 ) In addition, an uncoated area is provided around the negative electrode 17 divided into a plurality of divided areas.

[0047] When the electrolyte is injected into the internal space V, the gap including the combination of the channels in the positive electrode 16 and the channels in the negative electrode 17 serves as a flow path for the electrolyte in the same manner as the gap between the uncoated area 150 of one surface 15a and the uncoated area of ​​the other surface 15b.

[0048] In the uncoated region 150A provided in the region facing the injection port side surface 150P, the cross-sectional area [a] of the uncoated region 150A (in the direction in which the injection port side surface 150P extends ( Figure 3 The cross-sectional area of ​​the cross section perpendicular to the X direction in the channel 16b is greater than the cross-sectional area [d] of the channel 16b extending in the direction ( Figure 3 The cross-sectional area of ​​the cross section orthogonal to the Y direction in the graph.

[0049] Here, conventional batteries will be described. In conventional batteries, from the perspective of increasing battery capacity, it is considered to reduce the volume of the uncoated area where the active material layer is not formed on the current collector. However, sometimes it is difficult for the electrolyte to penetrate the channel arranged between the multiple active material layers in order to allow the electrolyte to penetrate. It is believed that this is because reducing the volume of the uncoated area makes it difficult for the electrolyte to penetrate the area in the internal space where the electrolyte initially penetrates from the injection port, in other words, it is difficult to penetrate the area of ​​the edge of the injection port formed facing the seal in the uncoated area. When the electrolyte becomes difficult to penetrate the area of ​​the edge of the injection port formed facing the seal in the uncoated area, the penetration of the electrolyte into the channel in front of the electrolyte travel direction will also slow down, and as a result, it takes time for the electrolyte to diffuse through the entire internal space. In addition, by reducing the area of ​​the edge of the injection port formed facing the seal in the uncoated area, the amount of electrolyte that can be present in the area will also become smaller. Therefore, it is difficult for the electrolyte to diffuse through the channel in front of those areas in the direction of the electrolyte travel, and as a result, it takes time for the electrolyte to diffuse through the entire internal space.

[0050] In contrast, in the embodiment of the present disclosure, the cross-sectional area of ​​the uncoated area 150A disposed in the area facing the injection port side surface 150P is set larger than that in the conventional battery, and the cross-sectional area [a] of the uncoated area 150A is larger than the cross-sectional area [d] of the channel 16b. Therefore, the electrolyte is more likely to penetrate the uncoated area 150A, which is the area in the internal space where the electrolyte initially penetrates from the injection port. In addition, since the volume of the uncoated area 150A is larger, the amount of electrolyte that can be present in the uncoated area 150A will also become larger. Therefore, the electrolyte is more likely to diffuse through the channel 16b that is in front of the uncoated area 150A in the direction of travel of the electrolyte, and the electrolyte is more likely to diffuse through the entire internal space V. As a result, the amount of time required for the electrolyte to fully penetrate the entire electrode stack 11 during the battery manufacturing process is shortened. In addition, the occurrence of defects in which the electrolyte fails to fully diffuse through the entire active material layer after the electrolyte injection is completed is also suppressed.

[0051] The ratio ([d] / [a]) of the cross-sectional area [d] of the channel 16b to the cross-sectional area [a] of the uncoated region 150A is preferably 0.1 to 0.9, more preferably 0.2 to 0.8, and even more preferably 0.2 to 0.5. When [d] / [a] is equal to or greater than the above lower limit and equal to or less than the above upper limit, the electrolyte is more easily diffused through the entire internal space V during injection of the electrolyte.

[0052] The cross-sectional area [d] of the channel 16b is preferably 0.4 mm 2 Up to 2.0mm 2 , more preferably 0.5 mm 2 Up to 1.0mm2 When the cross-sectional area [d] is equal to or greater than the above lower limit value, the electrolyte is more easily diffused during injection of the electrolyte throughout the entire internal space V. The cross-sectional area [d] is preferably equal to or less than the above upper limit value because this tends to increase the battery capacity.

[0053] The cross-sectional area [a] of the uncoated region 150A is preferably 0.4 mm 2 Up to 4.0mm 2 , more preferably 1.0 mm 2 Up to 3.0mm 2 When the cross-sectional area [a] is equal to or greater than the above lower limit value, the electrolyte is more easily diffused during injection of the electrolyte throughout the entire internal space V. The cross-sectional area [a] is preferably equal to or less than the above upper limit value because this tends to increase the battery capacity.

[0054] It should be noted that an example of a method of increasing the cross-sectional area [a] of the uncoated region 150A includes widening the width a of the uncoated region 150A. An example of a method of reducing the cross-sectional area [d] of the channel 16b includes narrowing the width d of the channel 16d.

[0055] The “cross-sectional area [a] of the region facing the injection port side surface in the uncoated region in a cross section perpendicular to the direction in which the injection port side surface extends” is the area of ​​the void derived from the “side adjacent to the injection port in the uncoated region” in the cross section obtained when the region including the side adjacent to the injection port in the uncoated region is cut along the direction perpendicular to the side. In addition, the “cross-sectional area [d] of the channel in a cross section perpendicular to the direction in which the channel extends” is the area of ​​the void “derived from an arbitrary channel” in the cross section obtained when the electrode stack is cut along the direction perpendicular to the direction in which the channel extends.

[0056] For the measurement of the cross-sectional area [a] of the uncoated region 150A, five arbitrary cross-sectional areas were measured in the direction extending from the injection port side surface 150P in the electrode stack ( Figure 3 The cross-sectional area of ​​the uncoated region 150A in the cross-sectional area orthogonal to the X direction in FIG. 1 and the arithmetic mean of the measured values ​​is used for the cross-sectional area [a]. Here, the cross-sectional area of ​​the uncoated region 150A is a value calculated by the following equation (1). Equation (1): The cross-sectional area of ​​the uncoated region 150A (mm 2 )= Figure 3 Length of a (mm) × thickness of partition area 16a (mm) For the measurement of the cross-sectional area [d] of the channel 16b, five arbitrary cross-sectional areas were measured in the direction in which the channel 16b in the electrode body extends ( Figure 3The cross-sectional area of ​​the channel 16b in the cross-sectional area orthogonal to the Y direction in FIG. 1 is measured, and the arithmetic mean of the measured values ​​is used for the cross-sectional area [d]. Here, the cross-sectional area of ​​the channel 16b is a value calculated by the following equation (2). Equation (2): Cross-sectional area of ​​channel 16b (mm 2 )= Figure 3 Length of d (mm) × thickness of partition area 16a (mm)

[0057] It will be necessary to explain that Figure 3 The descriptions of a and d are as follows. a: Width of the uncoated region 150A provided in the region facing the injection port side surface 150P (unit: mm) d: Width of channel 16b (unit: mm)

[0058] In the above embodiment, the aspect that the active material layers of both the positive electrode 16 and the negative electrode 17 have channels is described. However, the present embodiment is not limited thereto, and only the positive electrode active material layer or only the negative electrode active material layer may have channels. It will be noted that, from the viewpoint of suppressing lithium precipitation, it is preferred that channels be formed only in the positive electrode active material layer.

[0059] The size of the electrode stack in the battery according to the embodiment of the present disclosure is not particularly limited. The area of ​​the electrode stack when viewed from the stacking direction of the electrode stack may be, for example, 0.5 m 2 In addition, the upper limit of the area of ​​the electrode stack may be 4.0 m 2 the following.

[0060] It will be noted that the configuration of the present disclosure is not limited to the above-mentioned embodiments, and the configuration may be changed as appropriate as long as the problem of the present disclosure can be solved.

[0061] Next, the beneficial effects of the battery according to the embodiment of the present disclosure were confirmed through simulation experiments.

[0062] (Examples 1 to 3, Comparative Example 1) For Figure 3 The electrode stack of the configuration shown in the embodiment performs simulation (CEA), which has an active material layer on one surface of a metal plate acting as a current collector, has a divided region where the active material layer is divided by a channel, and has an uncoated region around the active material layer where the active material layer is not provided. The shape of the cross section of the channel and the uncoated region is rectangular. However, the number of channels is 14. Table 1 shows the width and cross-sectional area of ​​the following: Channel ( Figure 3 in the inner region sealed by the sealing body, in the region facing the edge of the sealing body having an injection port formed therein, an uncoated region A ( Figure 3 The uncoated region 150A in the active material layer), the uncoated region B ( Figure 3 uncoated region 150B in the active material layer), and an uncoated region C ( Figure 3 Uncoated area 150C).

[0063] In the simulation, the amount of time it took for the electrolyte to completely permeate the entire electrode stack (permeation time) was calculated. The results are shown in Table 1.

[0064] Table 1

[0065] As shown in Table 1, it will be understood that the amount of time taken for the electrolyte to completely penetrate the entire electrode stack in Examples 1 to 3, which satisfy the requirement that the cross-sectional area [a] of the uncoated region A is greater than the cross-sectional area [d] of the channel, is shorter than that of Comparative Example 1, which does not satisfy this requirement. It can be seen from this that in Examples 1 to 3, batteries with improved ability of the electrolyte to penetrate into the active material layer are obtained.

Claims

1. Batteries, including: An electrode stack comprising a stack of electrodes, each electrode in the stack of electrodes comprising a current collector and an active material layer, the active material layer being disposed on one or both surfaces of the current collector, and the active material layer being divided into a plurality of regions having channels therebetween; a sealing body which forms an internal space containing an electrolyte between adjacent current collectors and seals the internal space; as well as an injection port formed in the sealing body and connecting the internal space with the outside, in, The inner space is formed by the channel and an uncoated area around the active material layer where no active material layer is provided, When viewed from the stacking direction of the electrode stack, the inner region sealed by the sealing body has a polygonal shape, and When the surface of the sealing body on the inner space side of the side forming the injection port is referred to as the injection port side surface, The channel extends from one side of the injection port side surface in a direction opposite to the injection port side surface between the divided regions of the active material layer; and A cross-sectional area a of a region of the uncoated region facing the injection port side surface in a cross section perpendicular to a direction in which the injection port side surface extends is larger than a cross-sectional area d of the channel in a cross section perpendicular to the direction in which the channel extends.

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

3. The battery according to claim 1, wherein A ratio (d / a) of the cross-sectional area d of the channel to the cross-sectional area a of the uncoated region is 0.1 to 0.

9.

4. The battery according to claim 1, wherein The cross-sectional area d of the channel is 0.4 mm 2 Up to 2.0mm 2 .

5. The battery according to claim 1, wherein When viewed from the stacking direction of the electrode stack, the area of ​​the electrode stack is 0.5 m 2 above.

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