Energy storage device and method for manufacturing an energy storage device

Abstract

To provide a technology that can simultaneously suppress the peeling of the separator and shorten the liquid injection time. [Solution] A preferred embodiment of the manufacturing method disclosed herein includes a preparation step S1 in which a battery assembly is prepared, and an injection step S2 in which an electrolyte is injected into the battery assembly. In the injection step S2, the battery assembly is placed with a sealing plate having an injection hole facing upward, and the electrolyte is injected through an injection port inserted into the injection hole.

Description

[Technical Field]

[0001] This disclosure relates to an energy storage device and a method for manufacturing an energy storage device. [Background technology]

[0002] Japanese Patent Publication No. 2011-076952 discloses a sealed battery comprising an outer casing, an electrode group including a positive electrode and a negative electrode housed within the outer casing, a battery sealing body attached to the opening of the outer casing, and a spacer positioned in contact with the electrode group and a safety valve provided on the battery sealing body or the outer casing. The spacer is characterized in that it has a flat surface on the surface in contact with the electrode group, and that the flat surface forms a plurality of through passages. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2011-076952 [Overview of the project] [Problems that the invention aims to solve]

[0004] By the way, when increasing the size of the battery installed in a vehicle in order to increase its battery capacity, the amount of electrolyte to be injected increases. In particular, with large batteries, in order to complete the injection of electrolyte within a predetermined time, it is necessary to increase the amount of electrolyte injected per unit time. [Means for solving the problem]

[0005] A method for manufacturing an energy storage device disclosed herein comprises a preparation step of preparing an energy storage device assembly and an injection step of injecting an electrolyte into the energy storage device assembly. The energy storage device assembly comprises a case, an electrode body housed in the case, and a spacer. The case comprises a housing space for housing the electrode body and a side wall having an injection hole for injecting the electrolyte. The electrode body has a laminated structure in which a sheet-shaped positive electrode and a sheet-shaped negative electrode are stacked with a sheet-shaped separator in between. The end face of the laminated structure is arranged in the housing space so as to face the side wall. The spacer is arranged in the case between the side wall and the electrode body. It has a partition wall portion that faces the side wall and separates the housing space from the end space on the side wall side. The partition wall portion has a plurality of openings that penetrate the partition wall portion. The ratio of the total area of ​​the plurality of openings to the area of ​​the injection hole (total area of ​​openings / area of ​​injection hole) is 22 or more and 49 or less. The ratio of the total area of ​​the multiple openings to the cross-sectional area along the side wall of the case described above, which is set to 100%, is 8% or more. The ratio of the area of ​​the liquid injection holes to the cross-sectional area along the side wall of the case described above, which is set to 100%, is 0.2% or more. In the liquid injection process described above, the energy storage device assembly is placed with the side wall in which the liquid injection holes are formed facing upward, and the electrolyte is injected through the injection port inserted into the liquid injection holes. With this configuration, for example, even if the amount of liquid injected per unit time is increased, the peeling of the sheet-like separator can be suppressed. Furthermore, with this configuration, the time for injecting the electrolyte can be shortened.

[0006] The energy storage device disclosed herein comprises an electrode body, an electrolyte, a case housing the electrode body and the electrolyte, and a spacer. The case comprises a housing space for housing the electrode body and a side wall having an injection hole for injecting the electrolyte. The electrode body has a laminated structure in which a sheet-shaped positive electrode and a sheet-shaped negative electrode are stacked with a sheet-shaped separator in between. The end face of the laminated structure is arranged in the housing space so as to face the side wall. The spacer is arranged in the case between the side wall and the electrode body. It has a partition wall portion that faces the side wall and separates the housing space from the end space on the side wall side. The partition wall portion has a plurality of openings that penetrate the partition wall portion. The ratio of the total area of ​​the plurality of openings to the area of ​​the injection hole (total area of ​​openings / area of ​​injection hole) is 22 or more and 49 or less. The ratio of the total area of ​​the plurality of openings to the cross-sectional area of ​​the case along the side wall, which is 100%, is 8% or more. When the cross-sectional area along the side wall of the above case is taken as 100%, the ratio of the area of ​​the liquid injection hole is 0.2% or more. A power storage device with this configuration is a high-quality power storage device in which peeling of the sheet-like separator is suppressed. [Brief explanation of the drawing]

[0007] [Figure 1] Figure 1 is a schematic perspective view showing a battery according to one embodiment. [Figure 2] Figure 2 is a perspective view of a battery according to one embodiment, viewed from a different viewpoint than in Figure 1. [Figure 3] Figure 3 is a schematic cross-sectional view showing the internal structure of the battery shown in Figure 1. [Figure 4] Figure 4 is a schematic perspective view showing the electrode body of a battery according to one embodiment. [Figure 5] Figure 5 is a schematic perspective view showing a battery spacer according to one embodiment. [Figure 6] Figure 6 is a schematic enlarged cross-sectional view illustrating the injection of electrolyte into a battery according to one embodiment. [Figure 7]FIG. 7 is a schematic diagram for explaining the positional relationship between the liquid injection hole and the opening according to an embodiment. [Figure 8] FIG. 8 is a schematic diagram of the sealing plate according to an embodiment as viewed from above. [Figure 9] FIG. 9 is a flowchart showing a method for manufacturing a battery according to an embodiment. [Figure 10] FIG. 10 is a first schematic diagram for explaining the liquid injection process according to an embodiment. [Figure 11] FIG. 11 is a schematic diagram schematically showing a cross-section along the line A-A of FIG. 10. [Figure 12] FIG. 12 is a second schematic diagram for explaining the liquid injection process according to an embodiment. [Figure 13] FIG. 13 is a third schematic diagram for explaining the liquid injection process according to an embodiment.

Embodiments for Carrying Out the Invention

[0008] Hereinafter, some embodiments of the technology disclosed herein will be described with reference to the drawings. In the drawings, members and parts having the same function are appropriately assigned the same reference numerals. Also, the dimensional relationships (length, width, thickness, etc.) in each figure do not reflect the actual dimensional relationships. Note that matters other than those specifically mentioned in this specification and necessary for the implementation of the technology disclosed herein (for example, the general configuration and manufacturing process of a power storage device that does not characterize the present disclosure) can be grasped as design matters of those skilled in the art based on the prior art in the relevant field. The technology disclosed herein can be implemented based on the content disclosed in this specification and the common technical knowledge in the relevant field. Also, the following description is not intended to limit the present disclosure to the following forms.

[0009] In this specification, the notation "A~B" indicating a range means "A or greater and B or less." Furthermore, the notation "A~B" is intended to encompass the meanings of "greater than A" and "less than B." In this specification, "energy storage device" refers to a device capable of charging and discharging. Energy storage devices include batteries such as primary batteries and secondary batteries (e.g., non-aqueous electrolyte secondary batteries such as lithium-ion secondary batteries and nickel-metal hydride batteries), and capacitors (physical batteries) such as electric double-layer capacitors. The following explanation will use a lithium-ion secondary battery (hereinafter simply referred to as "battery"), which is one embodiment of the energy storage device disclosed herein, as an example. Note that the following explanation is not intended to limit energy storage devices to lithium-ion secondary batteries.

[0010] <Battery configuration> The following describes the battery 1 according to this embodiment. The battery 1 is obtained by the manufacturing method of the battery 1 described later. Here, Figure 1 is a schematic perspective view of the battery 1 according to one embodiment. Figure 2 is a perspective view of the battery 1 according to one embodiment from a different viewpoint than that of Figure 1. Figure 3 is a schematic cross-sectional view showing the internal structure of the battery 1 of Figure 1. Figure 4 is a schematic perspective view showing the electrode body 30 of the battery 1 according to one embodiment. Note that in Figure 4, only a portion of the positive electrode 32, negative electrode 34, and separator 36 of the electrode body 30 are shown for clarity. Figure 5 is a schematic perspective view showing the spacer 40A of the battery 1 according to one embodiment. Figure 6 is a schematic enlarged cross-sectional view to explain the injection of electrolyte E in the battery 1 according to one embodiment. Figure 7 is a schematic diagram to explain the positional relationship of the injection hole 22 and openings 43c1, 43c2 according to one embodiment. Note that in Figure 7, the sealing plate 20A and positive electrode terminal 50 are omitted for clarity. Figure 8 is a schematic diagram of a sealing plate according to one embodiment, viewed from above.

[0011] The symbols X, Y, and Z in the drawings indicate the long side direction, short side direction, and height direction of battery 1, respectively. The symbols X, Y, and Z in the drawings can also be referred to as the first direction, second direction, and third direction, respectively. However, these directions are defined for the sake of explanation. The installation configuration of battery 1 is not limited in any way by these directions. Furthermore, the following description will describe the case where the side wall is a sealing plate 20A, but this disclosure is not intended to be limited to this configuration.

[0012] As shown in Figures 1 to 3, the battery 1 according to this embodiment comprises an electrode body 30, an electrolyte E, a case 70, and spacers 40A and 40B.

[0013] As shown in Figure 3, the case 70 is a component that houses the electrode body 30 and the electrolyte E. The case 70 comprises a housing space 3 for housing the electrode body 30 and a sealing plate 20A having an injection hole 22 for pouring the electrolyte E. In the configuration shown in Figure 3, the case 70 is a roughly rectangular, flat, rectangular container. The case 70 comprises a case body 10 and sealing plates 20A and 20B.

[0014] The case body 10 is a flat, rectangular tubular member having a pair of substantially rectangular openings 12a, 12b (see Figure 3) at both ends in the long side direction X. The case body 10 has a storage space 3 of a required length along the long side direction X. In the configurations shown in Figures 1 and 2, the case body 10 comprises a pair of first side walls 14a, 14c facing each other in the height direction Z, and a pair of second side walls 14b, 14d facing each other in the short side direction Y. The first side walls 14a, 14c and the second side walls 14b, 14d are continuous in the circumferential direction so as to surround the storage space 3. The case body 10 can be manufactured, for example, by bending a single metal plate to form a tubular shape and joining the joint (e.g., by welding). In the configuration shown in Figure 1, the case body 10 has a welded joint 18 extending along the long side direction X on one of the first side walls 14a in the height direction Z. Furthermore, in the configuration shown in Figure 2, a thin-walled portion 14c1 is provided on the other first side wall 14c in the height direction Z. The thin-walled portion 14c1 is a safety valve that opens when the internal pressure of the containment space 3 becomes too high. The material that constitutes the case body 10 is preferably a metal material such as aluminum, aluminum alloy, iron, or iron alloy.

[0015] As shown in Figure 3, the sealing plates 20A and 20B are a pair of substantially rectangular plate-like members that close a pair of openings 12a and 12b of the case body 10. In this embodiment, the case 70 is constructed by sealing the openings 12a and 12b on both sides of the case body 10 with the sealing plates 20A and 20B. The pair of sealing plates 20A and 20B face each other in the direction of the long side X. Here, sealing plate 20A is attached to the opening 12a of the case body 10 on one side X1 in the direction of the long side X. Sealing plate 20B is attached to the opening 12b of the case body 10 on the other side X2 in the direction of the long side X. Sealing plate 20A is provided with a positive terminal 50, an injection hole 22, and a sealing plug 24. Sealing plate 20B is provided with a negative terminal 60. The materials used to make up the sealing plates 20A and 20B are preferably the same type of metal material as the case body 10 (aluminum, aluminum alloy, iron, iron alloy, etc.).

[0016] The positive electrode terminal 50 is preferably made of metal, and more preferably of aluminum or an aluminum alloy. As shown in Figure 3, the positive electrode terminal 50 is provided in the center of the first side wall 14a of the case body 10 in the opposing direction (height direction Z). The positive electrode terminal 50 comprises a positive electrode external terminal 52 and a positive electrode internal terminal 54. The positive electrode external terminal 52 penetrates the sealing plate 20A and is exposed outside the case 70. The positive electrode internal terminal 54 is housed inside the case 70. The positive electrode internal terminal 54 is connected to the electrode tab 30t (positive electrode tab 32t) of the electrode body 30. In this specification, the components that form a conductive path from the electrode body 30 inside the case 70 to the external terminal outside the case 70 are collectively referred to as "internal conductive members". In the battery 1 according to this embodiment, the positive electrode internal conductive member A1 is composed of the positive electrode internal terminal 54 and the positive electrode tab 32t. Furthermore, as shown in Figure 6, an insulating member 21 is provided to insulate the positive terminal 50 from the sealing plate 20A. The insulating member 21 may be made of a material used in conventionally known insulating members used in this type of battery 1.

[0017] The negative electrode terminal 60 is preferably made of metal, and more preferably of copper or a copper alloy. As shown in Figure 3, the negative electrode terminal 60 is provided in the center of the first side wall 14a of the case body 10 in the opposing direction (height direction Z). The negative electrode terminal 60 comprises a negative electrode external terminal 62 and a negative electrode internal terminal 64. The negative electrode external terminal 62 penetrates the sealing plate 20B and is exposed to the outside of the case 70. The negative electrode internal terminal 64 is housed inside the case 70. The negative electrode internal terminal 64 is connected to the electrode tab 30t (negative electrode tab 34t) of the electrode body 30. In the battery 1 according to this embodiment, the negative electrode internal conductive member A2 is composed of the negative electrode internal terminal 64 and the negative electrode tab 34t.

[0018] As shown in Figure 6, the injection hole 22 is an opening that penetrates the sealing plate 20A. The injection hole 22 is a hole for injecting the electrolyte E (see Figure 3) into the case 70. In this embodiment, the injection hole 22 is positioned offset in the height direction Z relative to the positive electrode terminal 50 to avoid interference with the positive electrode terminal 50. After the electrolyte E is injected into the case 70, the injection hole 22 is sealed by the sealing plug 24.

[0019] The electrode body 30 is the power generation element in the battery 1. As shown in Figure 3, the electrode body 30 is housed inside the case 70. Specifically, the electrode body 30 is positioned in the center of the long side direction X, between a pair of sealing plates 20A and 20B. The electrode body 30 according to this embodiment also comprises a sheet-like positive electrode 32, a sheet-like negative electrode 34, and a sheet-like separator 36 (see Figure 4). Although not particularly limited, "sheet-like" may mean, for example, a thickness in the range of 1 μm to 200 μm (preferably 1 μm to 100 μm).

[0020] As shown in Figure 4, the positive electrode 32 comprises a positive electrode current collector 32a, which is a conductive metal foil, and a positive electrode active material layer 32b applied to the surface of the positive electrode current collector 32a. A positive electrode tab 32t, in which the positive electrode current collector 32a is exposed, is provided on one side edge X1 in the long side direction X of the positive electrode 32. The positive electrode current collector 32a is substantially rectangular in shape. The positive electrode current collector 32a is made of a conductive metal such as aluminum, aluminum alloy, nickel, or stainless steel. The positive electrode current collector 32a is a metal foil, specifically aluminum foil. The positive electrode active material layer 32b has a positive electrode active material that can reversibly absorb and release charge carriers. As the positive electrode active material, an oxide containing at least one of Ni, Co, and Mn is preferably used. Examples of positive electrode active materials include lithium transition metal composite oxides such as lithium cobaltate, lithium manganeseate, lithium nickelate, lithium nickel manganese composite oxide, and lithium nickel cobalt composite oxide. The positive electrode active material is preferably a lithium nickel composite oxide containing Ni and Li, where the Ni content in the composite oxide is in the range of 70 mol% to 100 mol% relative to the total number of moles of constituent elements excluding Li and oxygen in the composite oxide. The positive electrode active material also includes those in which some of Ni, Co, and Mn are substituted with Al, Ti, Zr, P, B, Si, Nb, C, etc., or those in which the particle surface is covered with a compound containing Al, Ti, Zr, W, P, B, Si, Nb, C, etc. The above substitution and additive amounts together are approximately 0.1 mol% to 7 mol%.

[0021] On the other hand, the negative electrode 34 is the electrode opposite to the positive electrode 32. The negative electrode 34 comprises a negative electrode current collector 34a, which is a conductive metal foil, and a negative electrode active material layer 34b applied to the surface of the negative electrode current collector 34a. In addition, a negative electrode tab 34t is provided on the other side edge X2 in the long side direction X of the negative electrode 34, exposing the negative electrode current collector 34a. The negative electrode current collector 34a is substantially rectangular in this case. The negative electrode current collector 34a is made of a conductive metal such as copper, copper alloy, nickel, or stainless steel. In this case, the negative electrode current collector 34a is a metal foil, specifically a copper foil. The negative electrode active material layer 34b is provided on the negative electrode current collector 34a. The negative electrode active material layer 34b has a negative electrode active material that can reversibly absorb and release charge carriers. Examples of negative electrode active materials include carbon materials such as graphite and carbon, and metals and compounds that can absorb lithium, such as Si, SiO, SiC, and Sn.

[0022] The separator 36 is an insulating sheet interposed between the positive electrode 32 and the negative electrode 34. The separator 36 is substantially rectangular in shape. For example, a porous resin sheet made of polyolefin resin such as polyethylene (PE) or polypropylene (PP) is preferably used as the separator 36. A heat-resistant layer (HRL) containing an inorganic filler may be provided on the surface of the separator 36. Examples of inorganic fillers include alumina, boehmite, aluminum hydroxide, and titania.

[0023] The electrode body 30 according to this embodiment is a laminated electrode body. The shape of the electrode body 30 is a flat, approximately rectangular parallelepiped. The electrode body 30 has a pair of approximately rectangular wide surfaces. The electrode body 30 has a laminated structure in which a plurality of sheet-like positive electrodes 32 and sheet-like negative electrodes 34 are stacked on top of each other via sheet-like separators 36. As shown in Figure 3, at both end faces in the long side direction X of the electrode body 30, there is a pair of end faces 30A and 30B in which the ends of the sheet-like positive electrode 32, the sheet-like negative electrode 34, and the sheet-like separators 36 are exposed to the outside. The end faces 30A and 30B are the end faces (laminated surfaces) of the laminated structure of the electrode body 30. End face 30A is positioned in the housing space 3 so as to face the sealing plate 20A. End face 30B is also positioned in the housing space 3 so as to face the sealing plate 20B.

[0024] As shown in Figure 6, the end face 30A is positioned to face the liquid injection hole 22 of the sealing plate 20A when the electrode body 30 is housed in the case 70. The end face 30A is also positioned to face the partition walls 43a and 43b of the spacer 40A, which will be described later.

[0025] The size of the electrode body 30 is not particularly limited, as long as the effects of the technology disclosed herein are achieved. For example, in the case where the electrode body 30 has a pair of rectangular wide surfaces, as in this embodiment, the length in the direction of its long side X is, for example, 10 cm or more, 15 cm or more, and preferably 20 cm or more, and more preferably 25 cm or more (for example, 28 cm or more), from the viewpoint of suitability as an application target for the technology disclosed herein. The upper limit of the length of the electrode body 30 in the direction of its long side X is, for example, 50 cm or less, and may be 40 cm or less or 30 cm or less.

[0026] As shown in Figure 3, the electrode body 30 is covered with an insulating film 80. The shape of the insulating film 80 may be cylindrical, as in this embodiment, or it may be box-shaped or bag-shaped in other embodiments. Examples of materials that make up the insulating film 80 include polyolefin resins such as polyethylene (PE) and polypropylene (PP).

[0027] As shown in Figure 3, the electrolyte E is housed inside the case 70. The type of electrolyte E can be the same as that of a typical secondary battery and is not particularly limited. Electrolyte E is typically a non-aqueous liquid electrolyte (non-aqueous electrolyte) containing a non-aqueous solvent and a supporting salt. The non-aqueous solvent includes carbonates such as ethylene carbonate (EC), ethyl methyl carbonate (EMC), and dimethyl carbonate (DMC). The non-aqueous solvent is preferably a mixture of EC, EMC, and DMC in amounts ranging from 1% to 99% each, with a total volume ratio of 100%. The supporting salt is, for example, a fluorine-containing lithium salt. The fluorine-containing lithium salt preferably includes lithium hexafluorophosphate (LiPF6), lithium bis(fluorosulfonyl)imide (F2LiNO4S2) called LiFSI, or a mixture thereof. The concentration of the supporting salt is preferably 0.6 mol to 1.8 mol per liter of non-aqueous solvent.

[0028] In this embodiment, the electrolyte E is permeated into the interior of the electrode body 30. However, as in this embodiment, a portion of the electrolyte E may exist outside the electrode body 30 as excess electrolyte (more specifically, between the electrode body 30 and the case 70). Alternatively, in other embodiments, the electrolyte E may not exist outside the electrode body 30 as excess electrolyte. On the other hand, the former case is preferable because it is easier to replenish the electrolyte E inside the electrode body 30 when it becomes insufficient.

[0029] Regarding the amount of electrolyte E, refer to the section describing "amount of electrolyte" in the manufacturing method of battery 1 described later. As will be described later, in one preferred embodiment, the amount of electrolyte E is 200g or more. For example, large batteries with an electrolyte amount of 200g or more are suitable for application of the technology disclosed herein.

[0030] As shown in Figure 3, spacer 40A is positioned within the case 70 between the sealing plate 20A, which has an injection hole 22 for injecting the electrolyte E, and the electrode body 30. Spacer 40B is positioned within the case 70 between the sealing plate 20B and the electrode body 30. In this embodiment, spacers 40A and 40B are positioned on both sides of the electrode body 30 within the case 70, but in other embodiments, spacer 40A may be positioned only in the space between the sealing plate 20A with the injection hole 22 and the electrode body 30 within the case 70.

[0031] The material used to construct the spacer 40A can be any insulating resin that can be used in general batteries, without any particular restrictions. Examples of materials used to construct the spacer 40A include polyolefin resins such as polyethylene (PE) and polypropylene (PP), polyamide resins, polyimide resins, polyacetal resins, and polyester resins. These may be included individually or in combination of two or more. The spacer 40A can be manufactured, for example, by pressing, forging, or casting. The spacer 40B can be manufactured in a similar manner.

[0032] The structure of spacer 40A will now be described. As shown in Figures 5 and 6, spacer 40A faces the sealing plate 20A which has the liquid injection hole 22 and has partition walls 43a and 43b that separate the housing space 3 of the case 70 from the end space 4A on the sealing plate 20A side. Partition walls 43a and 43b each have a plurality of openings 43c1 and 43c2 that penetrate through them. The plurality of openings 43c1 are located at positions offset from the region of partition wall 43a that faces the liquid injection hole 22.

[0033] As shown in Figure 7, in this embodiment, the spacer 40A comprises first wall portions 41a, 41b and second wall portions 42a, 42b, 42c along the inside of the case 70. Also, as shown in Figure 5, a passage space 49 is formed in the middle portion of the spacer 40A for the passage of the positive electrode internal conductive member A1.

[0034] As shown in Figure 7, the first wall portion 41a of the spacer 40A is a wall portion positioned along the inside of the first side wall 14a of the case 70. The first wall portion 41b of the spacer 40A is a wall portion positioned along the inside of the first side wall 14c of the case 70. The second wall portion 42a of the spacer 40A is a wall portion positioned along the inside of the second side wall 14d of the case 70. The second wall portions 42b and 42c of the spacer 40A are wall portions positioned along the inside of the second side wall 14b of the case 70. The second wall portion 42b of the spacer 40A is positioned closer to one side Z1 in the height direction Z (the side of the first side wall 14a of the case 70) of the second side wall 14b of the case 70. The second wall portion 42c of the spacer 40A is positioned closer to the other side Z2 in the height direction Z (the side of the first side wall 14c of the case 70) of the second side wall 14b of the case 70. As shown in Figure 5, the second wall portions 42b and 42c of the spacer 40A are interrupted in the region where the passage space 49 is formed.

[0035] As shown in Figure 5, the spacer 40A has a first rib 44 that bridges the second wall portions 42a and 42c in the short-side direction Y. The first rib 44 is a flat plate-shaped member that extends from one side Y1 to the other side Y2 in the short-side direction Y. The partition wall portion 43a is partitioned by the first rib 44. The spacer 40A also has a second rib 46 and a third rib 47 on both sides of the passage space 49 that extend in the short-side direction Y. The second rib 46 and the third rib 47 are flat plate-shaped members. The second rib 46 is provided between the second wall portions 42a and 42b of the spacer 40A that are facing each other in the short-side direction Y. The third rib 47 is provided between the second wall portions 42a and 42c of the spacer 40A that are facing each other in the short-side direction Y.

[0036] As shown in Figure 5, the spacer 40A has a liquid channel 48 extending along the second wall portion 42a of the spacer 40A between the second rib 46 and the third rib 47. The liquid channel 48 is a flat plate-shaped member protruding inward from the second wall portion 42a. The liquid channel 48 bridges the partition walls 43a and 43b. One end 48a of the liquid channel 48 in the height direction Z1 is connected to the partition wall portion 43a. The other end 48b of the liquid channel 48 in the height direction Z2 is connected to the partition wall portion 43b.

[0037] Furthermore, as described above, the battery 1 according to this embodiment includes a positive electrode internal conductive member A1 (positive electrode internal terminal 54 and electrode tab 30t) that forms a conductive path from the electrode body 30 inside the case 70 to the external terminal (positive electrode external terminal 52) outside the case 70 (see Figure 3). The spacer 40A has a passage space 49 through which the positive electrode internal conductive member A1 passes. This makes it possible to easily form a conductive path from the electrode body 30 to the positive electrode external terminal 52 even when the spacer 40A is interposed between the sealing plate 20A and the electrode body 30. As shown in Figure 6, a portion of the electrolyte E flows downward in the direction of gravity (to the other side X2 of the long side direction X) through the passage space 49.

[0038] As shown in Figure 5, the partition walls 43a and 43b are supported by the first walls 41a and 41b and the second walls 42a, 42b, and 42c. The partition walls 43a and 43b are flat, substantially rectangular plate-like members that extend along the opposing direction (height direction Z) of the first side walls 14a and 14c, interposed between the electrode body 30 and the sealing plate 20A. The partition walls 43a and 43b are the parts that partition the space into which the electrolyte E is injected from the injection hole 22 and the end face 30A of the electrode body 30. As shown in Figure 6, the partition walls 43a and 43b face the sealing plate 20A and partition the housing space 3 and the end space 4A on the sealing plate 20A side. Also, as described above, a passage space 49 is formed in the spacer 40A. Therefore, the partition walls 43a and 43b are separated in a region that includes the central part in the height direction Z. The partition walls 43a and 43b are bridged by the second wall 42a on one side Y1 in the short side direction Y and the liquid flow path 48.

[0039] As shown in Figure 5, the spacer 40A has multiple openings 43c1 and 43c2 that penetrate the partition walls 43a and 43b. As shown in Figure 6, a portion of the electrolyte E poured into the case 70 flows through the openings 43c1 and 43c2 downward in the direction of gravity (the other X2 in the direction of the long side X).

[0040] The shapes of the openings 43c1 and 43c2 (the shapes of the openings 43c1 and 43c2 when viewed from above) are not particularly limited, as long as the effects of the technology disclosed herein are achieved. The shapes of the openings 43c1 and 43c2 may be oval-shaped, as in this embodiment, or in other embodiments, they may be circular, rectangular, triangular, or other shapes. From the viewpoint of allowing the electrolyte E to flow in more smoothly, the shapes of the openings 43c1 and 43c2 are preferably circular or oval-shaped without corners. Furthermore, the shapes of the multiple openings 43c1 and 43c2 may all be the same, as in this embodiment, or in other embodiments, some or all of them may be different. For example, the shapes of the multiple openings 43c1 and the multiple openings 43c2 may be different. Alternatively, the shapes of some or all of the multiple openings 43c1 may be different. Similarly, the shapes of some or all of the multiple openings 43c2 may be different. Furthermore, from the viewpoint of ease of manufacturing the spacer 40A, it is preferable that the shapes of the multiple openings 43c1 and 43c2 are all the same.

[0041] The number of openings 43c1 and 43c2 in the spacer 40A (hereinafter also simply referred to as "number of openings") is not particularly limited as long as the effects of the technology disclosed herein are achieved. The number of openings is, for example, 5 or more, preferably 10 or more, more preferably 15 or more, from the viewpoint of facilitating the uniform supply of electrolyte E to the electrode body 30. The upper limit of the number of openings is, for example, 30 or less, preferably 25 or less, more preferably 20 or less, from the viewpoint of suitably ensuring the strength of the spacer 40A. In this embodiment, the number of openings is 16.

[0042] In spacer 40A, the ratio of the total area of ​​the multiple openings 43c1 and 43c2 to the area of ​​the liquid injection hole 22 (total area of ​​openings / area of ​​liquid injection hole) is between 22 and 49. For details, refer to the section on "Ratio (total area of ​​openings / area of ​​liquid injection hole)" in the manufacturing method of battery 1 described later.

[0043] In spacer 40A, the ratio of the total area of ​​the multiple openings 43c1 and 43c2 to the cross-sectional area along the sealing plate 20A of case 70 (corresponding to the shaded area in Figure 11) is 8% or more. For details, refer to the relevant section in the manufacturing method of battery 1 described later.

[0044] In spacer 40A, the ratio of the area of ​​the liquid injection hole 22 (corresponding to area 22A in Figure 8) to the cross-sectional area along the sealing plate 20A of case 70, which is set to 100%, is 0.2% or more. For further details, please refer to the relevant section in the manufacturing method of battery 1 described later.

[0045] For the total area of ​​the multiple openings 43c1, 43c2 of the spacer 40A, refer to the section describing "total area of ​​openings" in the manufacturing method of the battery 1 described later. In one preferred embodiment, the total area of ​​the multiple openings 43c1, 43c2 is 200 mm². 2 That's all.

[0046] The area of ​​the liquid injection hole 22 in the sealing plate 20A can be found in the section describing "area of ​​liquid injection hole" in the manufacturing method of the battery 1 described later. In one preferred embodiment, the area of ​​the liquid injection hole 22 in the sealing plate 20A is 6 mm². 2 That's all.

[0047] As shown in Figure 7, the multiple openings 43c1 and 43c2 are located in the partition walls 43a and 43b at positions offset from the region facing the liquid injection holes 22. Here, "located at positions offset from the region facing the liquid injection holes" can include configurations in the partition wall 43a where no openings 43c1 exist in the region facing the liquid injection holes 22, or configurations where only a portion of the openings 43c1 exists in the region facing the liquid injection holes 22. On the other hand, in the manufacturing method of the battery 1 described later, the former is more preferable from the viewpoint of more reliably preventing the separator 36 from peeling.

[0048] The spacer 40A has been described above. As mentioned above, in the battery 1 according to this embodiment, a spacer 40B is also arranged on the other side X2 in the long side direction X. As shown in Figure 3, the spacer 40B faces the sealing plate 20B and separates the housing space 3 of the case 70 from the end space 4B on the sealing plate 20B side. Since the spacer 40B has substantially the same structure as the spacer 40A, a detailed explanation of its structure is omitted. In this embodiment, the structures of spacers 40A and 40B are the same, but they may be different in other embodiments.

[0049] <Battery manufacturing method> The manufacturing method of the battery 1 according to this embodiment will be described below. Here, Figure 9 is a flowchart of the manufacturing method of the battery 1 according to one embodiment. Figures 10, 12, and 13 are the first, second, and third schematic diagrams, respectively, for illustrating the liquid injection step S2 according to one embodiment. Figure 11 is a schematic diagram schematically showing a cross-section along line AA in Figure 10. Note that the following description of the manufacturing method is not intended to limit the manufacturing method of this disclosure to the following method. In addition, each step described below can be carried out in any order as appropriate. Furthermore, other steps may be added as necessary in addition to each step described below.

[0050] As shown in Figure 9, the manufacturing method of the battery 1 according to this embodiment comprises a preparation step S1 in which a battery assembly 2 is prepared, and an injection step S2 in which an electrolyte E is injected into the battery assembly 2. Furthermore, as shown in Figures 10, 12, and 13, in the injection step S2, the battery assembly 2 is placed with the sealing plate 20A, in which the injection holes 22 are formed, facing upward (here, one side X1 in the long side direction X), and the electrolyte E is injected through the injection port 120A inserted into the injection holes 22. In this specification, "opening" may mean a through hole in the partition wall that can serve as a flow path for the electrolyte. That is, openings in the partition wall provided for other purposes (for example, openings for passing electrode tabs or openings for passing electrode terminals) are not included in "opening". The following describes each step.

[0051] <Preparation Step S1> As described above, this step involves preparing the battery assembly 2. As shown in Figure 10, the battery assembly 2 comprises a case 70, an electrode body 30 housed in the case 70, and spacers 40A and 40B. The preparation step S1 according to this embodiment will now be described.

[0052] The battery assembly 2 can be constructed, for example, by the following method. First, the electrode body 30, case 70, and spacers 40A and 40B are assembled. Specifically, the multiple positive electrode tabs 32t on the electrode body 30 are joined to the positive electrode internal terminals 54. Also, the multiple negative electrode tabs 34t are joined to the negative electrode internal terminals 64. Then, the spacers 40A and 40B are attached to the electrode body 30 and the surrounding area is covered with insulating film 80. Next, the negative electrode external terminals 62 fixed to the sealing plate 20B are joined to the negative electrode internal terminals 64. This integrated assembly is inserted through one of the openings 12b of the case body 10. Next, the positive electrode external terminals 52 fixed to the sealing plate 20A are joined to the positive electrode internal terminals 54. Finally, the sealing plates 20A and 20B are welded to the openings 12a and 12b of the case body 10, respectively. In this configuration, the end face 30A of the laminated structure of the electrode body 30 is positioned to face the sealing plate 20A. In this embodiment, the sealing plate 20B is also positioned to face the end face 30B of the laminated structure. The battery assembly 2 can be assembled in this manner.

[0053] In the technology disclosed herein, the ratio of the total area of ​​the multiple openings 43c1, 43c2 to the area of ​​the injection hole 22 of the spacer 40A (total area of ​​openings / area of ​​injection hole) is 22 or more and 49 or less. The above ratio (total area of ​​openings / area of ​​injection hole) may be, for example, 25 or more, 30 or more, or 40 or more. Also, the above ratio (total area of ​​openings / area of ​​injection hole) may be, for example, 45 or less.

[0054] In this embodiment, "total area of ​​openings" refers to the total area of ​​16 openings 43c, consisting of 12 openings 43c1 located in the partition wall 43a and 4 openings 43c2 located in the partition wall 43b. The area of ​​each individual opening 43c1 or 43c2 corresponds to the shaded area (43d) in Figure 7. "Area of ​​opening" can also be referred to as the void area of ​​the opening. Alternatively, "area of ​​opening" can also be referred to as the area of ​​the opening viewed from above. Furthermore, in this embodiment, "area of ​​injection hole" refers to the area of ​​the injection hole 22 viewed from above. As described above, the area of ​​the injection hole 22 corresponds to the shaded area (22A) in Figure 8. The area of ​​the injection hole 22 can also be referred to as the area of ​​the portion of the injection hole 22 into which the electrolyte E flows.

[0055] In the technology disclosed herein, the ratio of the total area of ​​the multiple openings 43c1, 43c2 to the cross-sectional area of ​​the spacer 40A along the sealing plate 20A of the case 70, which is taken as 100%, (hereinafter also simply referred to as the "area ratio of the spacer openings") is 8% or more. The opening ratio of the spacer 40A is preferably 10% or more, and more preferably 15% or more, from the viewpoint of more effectively shortening the injection time of the electrolyte E. Furthermore, the upper limit of the opening ratio of the spacer 40A may be, for example, 20% or less, or 16% or less.

[0056] The "area ratio of the spacer openings" can be calculated by (total area of ​​openings / area of ​​the cross-section along the side wall) × 100%. For example, in this embodiment, the "area of ​​the cross-section along the side wall" refers to the area of ​​the case 70 along the sealing plate 20A having the liquid injection hole 22. Specifically, it refers to the area of ​​cross-section AA in Figure 10 (the area of ​​the shaded portion in Figure 11). The cross-sectional area of ​​the case 70, the total area of ​​the multiple openings 43c1, 43c2, and the area of ​​the liquid injection hole 22 can be measured, for example, by a CNC (Computerized Numerical Control) image measuring machine. Any commercially available device can be used as the CNC image measuring machine without any particular restrictions.

[0057] In the technology disclosed herein, when the cross-sectional area of the spacer 40A to be prepared along the sealing plate 20A of the case 70 is taken as 100%, the ratio of the area of the liquid injection hole 22 (hereinafter, also simply referred to as "the area ratio of the liquid injection hole") is 0.2% or more. From the viewpoint of more suitably realizing shortening of the liquid injection time of the electrolytic solution E, the area ratio of the liquid injection hole 22 is preferably 0.3% or more, and more preferably 0.4% or more. Also, the upper limit of the area ratio of the liquid injection hole 22 is, for example, 0.6% or less, and may be 0.5% or less.

[0058] Although not particularly limited, the average area of the plurality of openings 43c1, 43c2 is, for example, 10 mm 2 or more, and may be 15 mm 2 or more. On the other hand, in the liquid injection step S2 described later, from the viewpoint of more suitably achieving both shortening of the liquid injection time and prevention of the separator 36 from being turned up, the average area of the plurality of openings 43c1, 43c2 is preferably 20 mm 2 or more, 23 mm 2 or more. Also, the upper limit of the average area of the plurality of openings 43c1, 43c2 is, for example, 50 mm 2 or less. On the other hand, from the viewpoint of more suitably obtaining the effects as described above, it is preferably 40 mm 2 or less or 30 mm 2 or less.

[0059] In this specification, the "average area of the openings" may mean a value obtained by dividing the total area of the openings by the number of the openings. More specifically, it can be calculated by (total area of the openings / number of the openings). As described above, for example, in the present embodiment, the "total area of the openings" means the total area of the 16 openings 43c1, 43c2 including the 12 openings 43c1 arranged in the partition wall portion 43a and the 4 openings 43c2 arranged in the partition wall portion 43b. Also, as described above, the "number of the openings" is 16.

[0060] Although not particularly limited, the total area of the plurality of openings 43c1, 43c2 is, for example, 190 mm 2That concludes the explanation. On the other hand, in the liquid injection process S2 described later, from the viewpoint of more effectively shortening the liquid injection time, it is preferable to use 200 mm. 2 More than 230mm 2 The above, more preferably 280 mm 2 The above, and more preferably 400 mm 2 (For example, 420mm) 2 (The above.) Also, the upper limit of the total area of ​​multiple openings 43c1, 43c2 is, for example, 500 mm. 2 The following is 450mm 2 Below, 430mm 2 The following is also acceptable.

[0061] While not particularly limited, in the sealing plate 20A, the area of ​​the liquid injection hole 22 is, for example, 5 mm². 2 That concludes the explanation. On the other hand, from the viewpoint of more effectively shortening the injection time, the area of ​​the injection hole 22 is preferably 6 mm². 2 The above is more preferable to 8 mm 2 The above is the most preferred size, and 12 mm is particularly preferable. 2 That concludes the explanation. Furthermore, the upper limit of the area of ​​the injection hole 22 is, for example, 20 mm². 2 The following is 15mm 2 Below, 13mm 2 The following is also acceptable.

[0062] <Liquid injection process S2> As described above, in this step, electrolyte E is injected into the battery assembly 2. The injection step S2 according to this embodiment will be described below.

[0063] First, as shown in Figure 10, the battery assembly 2 is placed with the sealing plate 20A, which has the injection hole 22 formed therein, facing upward (here, one side X1 in the long side direction X). Then, in this embodiment, as shown in Figure 12, the electrolyte E is injected through the injection hole 22 using a hopper 100. More specifically, the electrolyte E is injected from the injection port 120A of the hopper 100 which is inserted into the injection hole 22. Compared to the conventional nozzle type, injection using a hopper 100 can shorten the injection time, but the amount of electrolyte E injected per unit time tends to be large. This has led to problems such as the separator 36 of the electrode body 30 peeling off. In contrast, according to the technology disclosed herein, even when the electrolyte E is injected using a hopper 100, peeling off the separator 36 can be suitably prevented.

[0064] Here, the hopper 100 is a component that injects the electrolyte E into the battery 1 through the injection hole 22. The shape of the hopper 100 is not particularly limited as long as the effects of the technology disclosed herein are achieved. In this embodiment, a funnel-shaped hopper 100 is used, as shown in Figure 12. The hopper 100 comprises an electrolyte storage section 110 and an injection section 120. The injection section 120 has an injection port 120A. Here, the electrolyte storage section 110 is the part that stores the electrolyte E. The injection section 120 is the part that injects the electrolyte E stored in the electrolyte storage section 110 into the battery 1 through the injection hole 22. The injection section 120 may be a thin tube as in this embodiment, or it may be a needle in other embodiments. The size of the electrolyte storage section 110 and the injection section 120 is preferably determined appropriately depending on the amount of electrolyte E to be injected. Furthermore, in this embodiment, the liquid injection unit 120 is equipped with a cock (not shown) that can adjust the ON / OFF of the injection of the electrolyte E. The hopper 100 may be made of metal, resin, or a combination of these. A commercially available hopper 100 can be used without any particular limitations.

[0065] Next, the electrolyte injection method according to this embodiment will be described. Specifically, first, as shown in Figure 10, the battery 1 is depressurized (see white arrow S). The conditions for depressurization are not particularly limited, as long as the effects of the technology disclosed herein are achieved. The pressure during depressurization can be, for example, in the range of -50kPa to -100kPa (preferably -70kPa to -100kPa). The time for depressurization can be, for example, in the range of 10 seconds to 60 seconds (preferably 20 seconds to 40 seconds). Next, as shown in Figure 12, the injection port 120A of the electrolyte injection section 120 of the hopper 100 is inserted into the electrolyte injection hole 22 of the battery 1. Then, a predetermined amount of electrolyte E is poured into the electrolyte storage section 110. Subsequently, while opening the cock of the electrolyte injection section 120 (not shown), pressurization is performed (see white arrow T). Although not limited to this, the pressure during pressurization can be, for example, in the range of 0.2MPa to 5MPa (preferably 0.5MPa to 2MPa). In this way, the electrolyte E can be injected into the battery 1 (see the white arrow U in Figure 12 and the white arrow V in Figure 13).

[0066] In one preferred embodiment, as in this embodiment, the multiple openings 43c1 are located at positions offset from the region in the partition wall 43a that faces the liquid injection holes 22. With this configuration, it is possible to more effectively prevent the electrolyte E from directly hitting the end face 30A of the laminated structure of the electrode body 30. Therefore, it is possible to more effectively prevent the separator 36 from peeling.

[0067] The amount of electrolyte E injected is, for example, 100g or more, and may be 150g or more. On the other hand, in one preferred embodiment, the amount of electrolyte E injected is 200g or more, more preferably 250g or more, or 280g or more. According to the manufacturing method of battery 1, peeling of the separator 36 can be suitably prevented. Therefore, for example, large batteries in which a large amount of electrolyte E is injected as described above tend to have a longer injection time, and are therefore suitable for application. Although not particularly limited, the upper limit of the amount of electrolyte E injected is, for example, 500g or less, and may be 400g or less or 300g or less. Also, although not particularly limited, the viscosity of the electrolyte E injected can be, for example, 0.1mPa·s to 1mPa·s (preferably 0.1mPa·s to 0.5mPa·s) at 25℃. Such viscosity can be measured, for example, using a commercially available rotational viscometer. As for the water and solvent mentioned above, for example, commercially available ones can be used without particular limitation.

[0068] While not limited thereto, the injection rate of the electrolyte E is, for example, 10 g / second or more, preferably 20 g / second or more, 30 g / second or more, and more preferably 40 g / second or more, 50 g / second or more, from the viewpoint of suitably shortening the injection time. Furthermore, the upper limit of the injection rate of the electrolyte E is, for example, 70 g / second or less, and preferably 60 g / second or less, from the viewpoint of suitably preventing the separator 36 from peeling. And, although not particularly limited, in one embodiment, from the viewpoint of suitably improving the productivity of the battery 1, the injection time of the electrolyte E is, for example, preferably 12 seconds or less, more preferably 10 seconds or less, and even more preferably 9 seconds or less, 8 seconds or less, or 5 seconds or less.

[0069] After the liquid injection process S2 is completed, the liquid injection hole 22 is sealed with the liquid injection plug 24. Then, appropriate processes such as initial charging and aging are performed to obtain the battery 1.

[0070] Battery 1 can be used for various purposes, but is particularly suitable as a power source (driving power supply) for motors mounted on vehicles such as passenger cars and trucks. The type of vehicle is not particularly limited, but examples include plug-in hybrid electric vehicles (PHEVs), hybrid electric vehicles (HEVs), and battery electric vehicles (BEVs).

[0071] From the perspective of improving the productivity of battery 1, there is a need to develop a technology that can simultaneously prevent the sheet-like separator 36 from peeling off and shorten the time required to inject the electrolyte E during the manufacturing of battery 1. According to the manufacturing method of battery 1 described above, in the injection process S2, the electrolyte E is injected through the injection hole 22 with a spacer 40A placed between the sealing plate 20A and the electrode body 30. Furthermore, the manufacturing method of the battery 1 described above is characterized by setting the ratio (total area of ​​openings / area of ​​injection holes), the area ratio of the spacer openings, and the area ratio of the injection holes within an appropriate range. This makes it possible to prevent the sheet-like separator 36 from peeling up and to shorten the injection time of the electrolyte E. In addition, the battery 1 obtained by the manufacturing method described above effectively prevents the separator 36 from peeling up. Therefore, the battery 1 can be said to be a high-quality battery.

[0072] Furthermore, the spacer 40A with the configuration described above has the following effects. First, as shown in Figure 6, the electrolyte E injected from the injection hole 22 flows onto the partition wall 43a. At this time, a portion of the electrolyte E flows in through the opening 43c1 of the partition wall 43a. This allows the electrolyte E to be supplied to one end Z2 in the height direction Z. Also, a portion of the electrolyte E that has diffused in the partition wall 43a flows in through the passage space 49 that allows the positive electrode internal conductive member A to pass through. This allows the electrolyte E to be supplied to the center in the height direction Z. The remaining electrolyte E travels through the liquid flow path 48 to the partition wall 43b and flows in through the opening 43c2 of the partition wall 43b. This allows the electrolyte E to be supplied to the other end Z1 in the height direction Z. As described above, since the first spacer 40A has a liquid flow path 48, the electrolyte E can be injected more efficiently over the entire height range Z.

[0073] As described above, the spacer 40A comprises first wall portions 41a, 41b and second wall portions 42a, 42b, 42c. This effectively prevents deformation of the spacer 40A even when, for example, an impact is applied to the battery 1 in the long-side direction X. In spacer 40A, the deformation of the second wall portions 42a, 42c extending inward in the short-side direction Y can be further restricted by the first rib 44, second rib 46, and third rib 47. The same applies to spacer 40B. Furthermore, spacers 40A and 40B can prevent electrical contact between the electrode body 30 and the sealing plates 20A and 20B. In addition, spacers 40A and 40B can restrict the movement of the electrode body 30 in the long-side direction X. This prevents damage to the electrode body 30 (e.g., electrode tab 30t).

[0074] [Example Test] The following describes examples of tests related to the technology disclosed herein. Note that the content of the test examples described below is not intended to limit the scope of the technology disclosed herein.

[0075] 1. Preparation of test batteries In this study, nine different test batteries were prepared with varying total opening areas and injection hole areas. The injection time was measured, and the presence or absence of separator peeling was checked. The preparation of each test battery is described below.

[0076] (Examples 1-8) As a test battery, we fabricated a battery as shown in Figure 3. Specifically, first, we fabricated a laminated electrode body (length 284 mm in the long side direction × length 88 mm in the height direction × length 13 mm in the short side direction) in which multiple sheet-shaped positive electrodes and sheet-shaped negative electrodes were stacked with sheet-shaped separators in between. Here, lithium nickel cobalt manganese composite oxide (LiNi) was used as the positive electrode active material. 1 / 3 Co 1 / 3 Mn 1 / 3 O2 was used. Aluminum foil was used for the positive electrode current collector. On the other hand, graphite was used for the negative electrode active material. Copper foil was used for the negative electrode current collector. A 3-layer separator of PP / PE / PE was used for the separator. Two laminated electrode bodies prepared as described above were inserted into a rectangular tubular case body (made of aluminum, 308 mm in length in the long direction × 90 mm in height direction × 30 mm in the short direction) with spacers attached. In Examples 1 to 8, spacers were used whose total opening area and the area ratio of the spacer openings were the values ​​shown in Table 1. Also, in Examples 1 to 8, sealing plates with liquid injection holes of the area shown in Table 1 were used. The total opening area of ​​the spacer was varied by increasing or decreasing the number of openings in the spacer. The average area of ​​the spacer openings was 23.7 mm². 2 Then, the openings on both sides of the case body were sealed using sealing plates.

[0077] (Example 9) A test battery according to Example 7 was manufactured in the same manner as in Examples 1-6 and 8-10, except that two stacked electrode bodies were inserted into the case body without spacers.

[0078] 2. Measurement of injection time First, as shown in Figure 10, the pressure inside each test battery was reduced to -96 kPa or below for 30 seconds. Then, as shown in Figure 12, a hopper was attached to the electrolyte injection port, and the entire amount of electrolyte was poured into the electrolyte container of the hopper. In Examples 1 to 9, 289 g of electrolyte was poured into each electrolyte container. Then, as shown in Figure 13, the injection port was opened, and the electrolyte was injected into each test battery while pressurizing the electrolyte container to 0.8 MPa. The time from the start of electrolyte injection until the electrolyte in the electrolyte container was depleted was measured as the injection time. The results are shown in the "Injection Time" column of Table 1. Here, an "Injection Time" of 12 seconds or less (preferably 10 seconds or less) is considered to have been shortened. As the electrolyte, a mixed solvent (non-aqueous electrolyte) containing ethylene carbonate (EC), dimethyl carbonate (DMC), and ethyl methyl carbonate (EMC) in a volume ratio of 3:4:3 was prepared. In addition, a solution of LiPF6 dissolved at a concentration of 1.0 mol / L was used as a supporting salt.

[0079] 3. Check for any peeling or damage to the separator. First, each test battery was disassembled after the electrolyte was injected. Then, the electrode body was removed from each test battery, and it was visually inspected to see if the separator on the electrode body was peeled back. The results are shown in the "Presence or Absence of Separator Peeling" column of Table 1. "×" indicates that the separator was peeled back on the electrode body, and "〇" indicates that the separator was not peeled back on the electrode body.

[0080] [Table 1]

[0081] As shown in Table 1, in Examples 1 to 5, where the above ratio (total area of ​​spacer openings / area of ​​injection holes) is between 22 and 49, the area ratio of the injection holes is 0.2% or more, and the area ratio of the spacer openings is 8% or more, it was confirmed that the injection time was shortened and the peeling of the separator was effectively prevented. On the other hand, in Examples 6 to 8, where the above ratio (total area of ​​spacer openings / area of ​​injection holes) is outside the above range, and in Example 9, which does not have a spacer, it was confirmed that shortening the injection time and preventing the peeling of the separator could not be achieved simultaneously.

[0082] Furthermore, from Examples 1-5, when all of the above conditions are met, the total area of ​​the spacer openings is 200 mm². 2 (For example, 230mm) 2 It was confirmed that the above conditions are preferable. Furthermore, from Examples 1 to 5, when the above conditions are met, the area of ​​the injection hole is 6 mm 2 It was confirmed that the above is preferable.

[0083] Furthermore, it was confirmed that the peeling of the separator can be effectively prevented even when the electrolyte is injected using a hopper. By using a hopper, the injection time can be effectively shortened compared to conventional nozzle-type systems.

[0084] The embodiments of the technology disclosed herein have been described above. However, the above description is illustrative and does not limit the scope of the claims. The technologies described in the claims include various modifications and changes to the specific examples illustrated in the above description.

[0085] For example, although the above test example used a large battery, the technology disclosed here can, of course, be applied to batteries other than large batteries as well.

[0086] For example, in the embodiment described above, the electrode body 30 is a laminated electrode body, but it is not limited to this. In other embodiments, the electrode body 30 may be a wound electrode body in which a laminate is formed by winding up a plurality of sheet-shaped positive electrodes 32 and sheet-shaped negative electrodes 34 stacked on top of each other via a sheet-shaped separator 36. Also, the number of electrode bodies 30 provided in the battery 1 may be two, as in this embodiment, or one or three or more in other embodiments. Furthermore, in other embodiments, the electrode body 30 may not have positive electrode tabs 32t and negative electrode tabs 34t.

[0087] For example, in the embodiment described above, the case 70 is approximately rectangular, but unless otherwise specified, the shape of the case 70 is not limited. For example, the case 70 may be various shapes such as cylindrical. Also, if the case 70 is cylindrical, the electrode body 30 may be a cylindrical wound electrode body housed inside the case 70. Furthermore, the spacers 20A and 20B may be disc-shaped members placed between the side wall of the case 70 and the electrode body 30 within the cylindrical case 70.

[0088] For example, in the embodiment described above, the sealing plate 20A having the positive terminal 50 has an injection hole 22, but the embodiment is not limited to this. In other embodiments, the sealing plate 20B having the negative terminal 60 may also have an injection hole 22.

[0089] For example, in the embodiment described above, the sealing plates 20A and 20B are equipped with a positive electrode terminal 50 and a negative electrode terminal 60, respectively, but are not limited to this. In other embodiments, both the positive electrode terminal 50 and the negative electrode terminal 60 may be arranged on one of the sealing plates 20A and 20B. In such cases, for example, the sealing plate equipped with the positive electrode terminal 50 and the negative electrode terminal 60 can be provided with an electrolyte injection hole 22. Alternatively, in other embodiments, the battery may comprise an outer casing having a bottom wall, a pair of first side walls extending from the bottom wall and facing each other, a pair of second side walls extending from the bottom wall and facing each other, and an opening facing the bottom wall, and a sealing plate that seals the opening of the outer casing. In such cases, for example, electrode terminals and an electrolyte injection hole can be arranged on the sealing plate.

[0090] For example, in the above embodiment, the spacer 40A comprises first wall portions 41a, 41b, second wall portions 42a, 42b, 43c, and partition wall portions 43a, 43b, but the shape of the spacer is not limited to this.

[0091] For example, in the above embodiment, the electrolyte E is injected through the injection hole 22 using a hopper, but this is not the only option. In other embodiments, the electrolyte can be injected using a nozzle. On the other hand, from the viewpoint of suitably shortening the injection time, it is more preferable to use a hopper that can inject a large amount of electrolyte E at once.

[0092] As described above, specific embodiments of the technology disclosed herein include those described in the following sections.

[0093] Section 1: The preparation process for preparing the energy storage device assembly, An injection step of injecting an electrolyte into the energy storage device assembly, Equipped with, Here, The aforementioned energy storage device assembly is The case and, The electrode body housed in the aforementioned case, Spacer and Equipped with, The aforementioned case is, The system comprises a housing space for housing the electrode body and a side wall having an injection hole for pouring the electrolyte, The electrode body is It has a laminated structure in which a sheet-shaped positive electrode and a sheet-shaped negative electrode are stacked with a sheet-shaped separator in between. The end face of the laminated structure is positioned in the storage space so as to face the side wall, The previous spacer is Within the case, the following is arranged between the side wall and the electrode body: It has a partition wall portion that faces the aforementioned side wall and separates the accommodation space from the end space on the side wall side, The partition wall portion has a plurality of openings that penetrate the partition wall portion, The ratio of the total area of ​​the multiple openings to the area of ​​the injection hole (total area of ​​openings / area of ​​injection hole) is 22 or more and 49 or less. When the cross-sectional area along the side wall of the case is taken as 100%, the ratio of the total area of ​​the multiple openings is 8% or more. When the cross-sectional area along the side wall of the case is taken as 100%, the ratio of the area of ​​the liquid injection hole to that area is 0.2% or more. In the aforementioned liquid injection step, The energy storage device assembly is placed with the side wall in which the liquid injection hole is formed facing upward, and the electrolyte is injected through the liquid injection port inserted into the liquid injection hole. A method for manufacturing energy storage devices.

[0094] Section 2: The method for manufacturing an energy storage device according to item 1, wherein the electrolyte is injected using a hopper in the liquid injection step.

[0095] Section 3: The method for manufacturing an energy storage device according to item 1 or 2, wherein the amount of the electrolyte is 200 g or more.

[0096] Section 4: In the aforementioned spacer, the total area of ​​the multiple openings is 200 mm². 2The method for manufacturing an energy storage device as described in any one of items 1 to 3 above.

[0097] Section 5: In the aforementioned side wall, the area of ​​the injection hole is 6 mm². 2 The method for manufacturing an energy storage device as described in any one of items 1 to 4 above.

[0098] Item 6: The method for manufacturing an energy storage device according to any one of items 1 to 5, wherein the plurality of openings are located at positions offset from the region in the partition wall that faces the liquid injection hole.

[0099] Section 7: Electrode body and Electrolyte and A case containing the electrode body and the electrolyte, Spacer and, Equipped with, The case comprises a housing space for housing the electrode body and a side wall having an injection hole for pouring the electrolyte, The electrode body is It has a laminated structure in which a sheet-shaped positive electrode and a sheet-shaped negative electrode are stacked with a sheet-shaped separator in between. The end face of the laminated structure is positioned in the storage space so as to face the side wall, The previous spacer is Within the case, the following is arranged between the side wall and the electrode body: It has a partition wall portion that faces the aforementioned side wall and separates the accommodation space from the end space on the side wall side, The partition wall portion has a plurality of openings that penetrate the partition wall portion, The ratio of the total area of ​​the multiple openings to the area of ​​the injection hole (total area of ​​openings / area of ​​injection hole) is 22 or more and 49 or less. When the cross-sectional area along the side wall of the case is taken as 100%, the ratio of the total area of ​​the multiple openings is 8% or more. The ratio of the area of ​​the liquid injection hole to the cross-sectional area along the side wall of the case, when that area is taken as 100%, is 0.2% or more. Energy storage device.

[0100] Section 8: The energy storage device according to item 7, wherein the amount of the electrolyte is 200 g or more.

[0101] Section 9: In the aforementioned spacer, the total area of ​​the multiple openings is 200 mm². 2 The energy storage device described in item 7 or 8 above.

[0102] Section 10: In the aforementioned side wall, the area of ​​the injection hole is 6 mm². 2 The above is a power storage device as described in any one of items 7 to 9.

[0103] Section 11: The energy storage device according to any one of claims 7 to 10, wherein the plurality of openings are located at positions offset from the region in the partition wall that faces the liquid injection hole. [Explanation of symbols]

[0104] 1 battery 2 Battery Assembly 3. Containment space 4A,4B End space 10 Case body 12a,12b opening 14a,14c 1st side wall 14b,14d 2nd side wall 20A,20B Sealing plate 21 Insulating material 22 Liquid injection hole 24 Sealing plug 30 Electrode body 40A, 40B Spacer 41a,41b 1st wall part 42a,42b,42c 2nd wall part 43a, 43b Partition wall section 43c1,43c2 opening 44. First Rib 46. ​​Second Rib 47 Third Rib 48 Liquid flow path 49 Passage space 50 Positive terminal 60 Negative terminal 70 cases 80 Insulating film 100 hoppers 110 Electrolyte storage section 120 Injection section

Claims

1. Preparation process for preparing energy storage device assemblies, An injection step of injecting an electrolyte into the energy storage device assembly, Equipped with, Here, The aforementioned energy storage device assembly is The case and, The electrode body housed in the aforementioned case, Spacer and Equipped with, The aforementioned case is, The system comprises a housing space for housing the electrode body and a side wall having an injection hole for pouring the electrolyte, The electrode body is It has a laminated structure in which a sheet-shaped positive electrode and a sheet-shaped negative electrode are stacked with a sheet-shaped separator in between. The end face of the laminated structure is positioned in the storage space so as to face the side wall, The previous spacer is Within the case, the following is arranged between the side wall and the electrode body: It has a partition wall portion that faces the aforementioned side wall and separates the accommodation space from the end space on the side wall side, The partition wall portion has a plurality of openings that penetrate the partition wall portion, The ratio of the total area of ​​the multiple openings to the area of ​​the injection hole (total area of ​​openings / area of ​​injection hole) is 22 or more and 49 or less. When the cross-sectional area along the side wall of the case is taken as 100%, the ratio of the total area of ​​the multiple openings is 8% or more. When the cross-sectional area along the side wall of the case is taken as 100%, the ratio of the area of ​​the liquid injection hole to that area is 0.2% or more. In the aforementioned liquid injection step, The energy storage device assembly is placed with the side wall in which the liquid injection hole is formed facing upward, and the electrolyte is injected through the liquid injection port inserted into the liquid injection hole. A method for manufacturing energy storage devices.

2. The method for manufacturing an energy storage device according to claim 1, wherein the electrolyte is injected using a hopper in the liquid injection step.

3. The method for manufacturing an energy storage device according to claim 1 or 2, wherein the amount of the electrolyte is 200 g or more.

4. In the aforementioned spacer, the total area of ​​the multiple openings is 200 mm². ２ The method for manufacturing an energy storage device according to claim 1 or 2.

5. In the aforementioned side wall, the area of ​​the injection hole is 6 mm². ２ The method for manufacturing an energy storage device according to claim 1 or 2.

6. The method for manufacturing an energy storage device according to claim 1 or 2, wherein the plurality of openings are located at positions offset from the region in the partition wall that faces the liquid injection hole.

7. Electrode body and Electrolyte and A case containing the electrode body and the electrolyte, Spacer and, Equipped with, The case comprises a housing space for housing the electrode body and a side wall having an injection hole for pouring the electrolyte, The electrode body is It has a laminated structure in which a sheet-shaped positive electrode and a sheet-shaped negative electrode are stacked with a sheet-shaped separator in between. The end face of the laminated structure is positioned in the storage space so as to face the side wall, The previous spacer is Within the case, the following is arranged between the side wall and the electrode body: It has a partition wall portion that faces the aforementioned side wall and separates the accommodation space from the end space on the side wall side, The partition wall portion has a plurality of openings that penetrate the partition wall portion, The ratio of the total area of ​​the multiple openings to the area of ​​the injection hole (total area of ​​openings / area of ​​injection hole) is 22 or more and 49 or less. When the cross-sectional area along the side wall of the case is taken as 100%, the ratio of the total area of ​​the multiple openings is 8% or more. The ratio of the area of ​​the liquid injection hole to the cross-sectional area along the side wall of the case, when that area is taken as 100%, is 0.2% or more. Energy storage device.

8. The energy storage device according to claim 7, wherein the amount of the electrolyte is 200 g or more.

9. In the aforementioned spacer, the total area of ​​the multiple openings is 200 mm². ２ The energy storage device according to claim 7 or 8.

10. In the aforementioned side wall, the area of ​​the injection hole is 6 mm². ２ The energy storage device according to claim 7 or 8.

11. The energy storage device according to claim 7 or 8, wherein the plurality of openings are located at positions offset from the region in the partition wall that faces the liquid injection hole.

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