Nonaqueous electrolyte secondary battery

Abstract

To shorten a time required for uniformly osmosing an electrolytic solution to the inside of an electrode body.SOLUTION: A secondary battery 1 disclosed herein includes a case body 10, a sealing plate 20, an electrode body 30, an electrolytic solution, and a spacer 40. The spacer 40 includes a pair of first wall parts 41 along first side surfaces 14a, 14b of the case body 10, and a partition part 43 extending along an opposed direction (third direction Z) of the first side surfaces 14a, 14b so as to be disposed between the electrode body 30 and the sealing plate 20. In the secondary battery 1, a liquid injection hole 22 and the partition part 43 are opposed while keeping a constant space between them, and a diffusion member 44 to diffuse the electrolytic solution, which is injected from the liquid injection hole 22, along the partition part 43 is provided on the partition part 43. With such a configuration, the electrolytic solution can be supplied to a wide range along the third direction Z, so that a time required for uniformly osmosing the electrolytic solution to the inside of the electrode body can be shortened.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The technology disclosed herein relates to a non-aqueous electrolyte secondary battery. [Background technology]

[0002] A nonaqueous electrolyte secondary battery (hereinafter simply referred to as a "secondary battery") includes, for example, an electrode assembly, an electrolyte, and a battery case that houses the electrode assembly and the electrolyte. The battery case is formed with an opening (a liquid inlet) for injecting the electrolyte. The electrolyte injected into the battery case then permeates the inside of the electrode assembly (between the positive and negative electrode plates). If the electrolyte is directly sprayed onto the electrode assembly during this injection, the electrode assembly may be damaged. For this reason, a partition (a liquid receiving portion) is sometimes placed between the liquid inlet and the electrode assembly. This weakens the momentum of the injected electrolyte, thereby preventing damage to the electrode assembly. Examples of secondary batteries having such a liquid receiving portion are disclosed in Patent Documents 1 and 2. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2023-92256 [Patent Document 2] Japanese Patent Application Publication No. 2019-129129 Summary of the Invention [Problem to be solved by the invention]

[0004] Meanwhile, secondary battery manufacturing sites require a technology that can uniformly infiltrate the electrolyte into the electrode assembly in a short time. Specifically, when injecting the electrolyte, the electrolyte tends to be supplied to positions close to the injection hole, but is difficult to supply to positions far from the injection hole. For this reason, it is necessary to ensure a very long retention time after injection to ensure that the electrolyte sufficiently infiltrates even positions far from the injection hole.

[0005] The technology disclosed herein has been made in view of the above circumstances, and aims to shorten the time required for the electrolyte to uniformly permeate the interior of the electrode body. [Means for solving the problem]

[0006] The nonaqueous electrolyte secondary battery disclosed herein includes a rectangular tubular case body having a pair of openings at both ends, a pair of sealing plates that form the battery case by closing the pair of openings, an electrode assembly housed inside the battery case, an electrolyte housed inside the battery case, and a spacer disposed in at least one of the spaces between the sealing plate and the electrode assembly. The rectangular tubular case body includes a pair of first side surfaces that are rectangular plate-like portions facing each other, and a pair of second side surfaces that are rectangular plate-like portions facing each other and extend from an edge of one of the first side surfaces to an edge of the other first side surface. At least one of the pair of sealing plates includes a liquid inlet that penetrates the sealing plate and a sealing plug that seals the liquid inlet. The spacer includes a pair of first walls along at least a portion of the pair of first side surfaces of the case body, a pair of second walls along at least a portion of the pair of second side surfaces of the case body, and a partition that is a plate-like member extending along the opposing direction of the pair of first side surfaces so as to be interposed between the electrode body and the sealing plate and is supported by the first and second walls. In the secondary battery disclosed herein, the liquid injection hole and the partition face each other with a certain space between them, and the partition is provided with a diffusion member that diffuses the electrolyte injected from the liquid injection hole along the partition.

[0007] As described above, the case body of the secondary battery has a pair of first side surfaces facing each other. The spacer has a partition extending along the facing direction of the first side surfaces. The spacer of the secondary battery disclosed herein is provided with a diffusion member that diffuses the electrolyte solution. The electrolyte solution that comes into contact with the diffusion member is diffused along the partition. This allows the electrolyte solution to be supplied over a wide area along the facing direction of the case body, thereby shortening the time required for the electrolyte solution to uniformly penetrate into the electrode assembly. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a perspective view schematically showing a secondary battery according to one embodiment. [Figure 2] FIG. 2 is a perspective view of the secondary battery according to one embodiment, viewed from a different viewpoint than that of FIG. [Figure 3] FIG. 3 is a cross-sectional view schematically showing the internal structure of the secondary battery of FIG. [Figure 4] FIG. 4 is an enlarged cross-sectional view illustrating injection of an electrolyte solution into a secondary battery according to one embodiment. [Figure 5] FIG. 5 is a perspective view schematically showing an electrode assembly of a secondary battery according to one embodiment. [Figure 6] FIG. 6 is a perspective view schematically illustrating a spacer of a secondary battery according to one embodiment. [Figure 7] FIG. 7 is an enlarged cross-sectional view illustrating injection of an electrolyte solution into a secondary battery according to another embodiment. [Figure 8] FIG. 8 is an enlarged cross-sectional view illustrating injection of an electrolyte solution into a secondary battery according to another embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, several embodiments of the technology disclosed herein will be described in detail with reference to the drawings. It should be noted that matters other than those specifically mentioned in this specification that are necessary for implementing the technology disclosed herein (e.g., the general configuration and manufacturing process of a secondary battery) can be understood as design matters for those skilled in the art based on the prior art in the relevant field. The technology disclosed herein can be implemented based on the contents disclosed in this specification and the technical common sense in the relevant field. Furthermore, in the following drawings, components and parts that perform the same function are denoted by the same reference numerals.

[0010] First Embodiment An embodiment of the nonaqueous electrolyte secondary battery disclosed herein will be described below. FIG. 1 is a perspective view schematically illustrating a secondary battery according to this embodiment. FIG. 2 is a perspective view of the secondary battery according to this embodiment, viewed from a different perspective than that of FIG. 1. FIG. 3 is a cross-sectional view schematically illustrating the internal structure of the secondary battery of FIG. 1. FIG. 4 is an enlarged cross-sectional view illustrating injection of an electrolyte into the secondary battery according to this embodiment. FIG. 5 is a perspective view schematically illustrating an electrode body of the secondary battery according to this embodiment. FIG. 6 is a perspective view schematically illustrating a spacer of the secondary battery according to this embodiment. In this specification, the symbols X, Y, and Z in the drawings are referred to as a first direction, a second direction, and a third direction, respectively. However, these directions are defined for convenience of explanation and do not limit the installation mode of the secondary battery in any way.

[0011] 1 to 4, the secondary battery 1 according to this embodiment includes a case body 10, a sealing plate 20, an electrode assembly 30, an electrolyte (not shown), and a spacer 40. Each component will be described below.

[0012] (1) Case body The case body 10 is a rectangular cylindrical member having a pair of openings 12 (see FIG. 3) at both ends in the first direction X. The case body 10 includes a pair of first side surfaces 14a, 14b and a pair of second side surfaces 16a, 16b. The first side surfaces 14a, 14b are a pair of plate-like portions facing each other in the third direction Z. The first side surfaces 14a, 14b each extend along the first direction X. In this specification, the direction in which the pair of first side surfaces 14a, 14b face each other (i.e., the third direction Z in the drawings) is also referred to as the "facing direction of the first side surfaces." On the other hand, the second side surfaces 16a, 16b are rectangular plate-like portions extending from an edge 14a1 of one first side surface 14a toward an edge 14b1 of the other first side surface 14b, as shown in FIGS. 1 and 2. The second side surfaces 16a, 16b face each other in the second direction Y. The second side surfaces 16a, 16b also extend along the first direction X. This case body 10 can be produced by bending a single metal plate into a cylindrical shape and joining (for example, welding) the seams. Therefore, in the case body 10 shown in FIG. 1, a welded joint 18 extending along the first direction X is formed on the first side surface 14a on one side Z1 of the third direction Z. Note that the case body 10 is preferably made of a metal material such as aluminum, an aluminum alloy, iron, or an iron alloy.

[0013] (2) Sealing plate The sealing plates 20 are a pair of plate-like members that close a pair of openings 12 in the case body 10. In this embodiment, the battery case 70 is constructed by sealing the openings 12 in the case body 10 with the sealing plates 20. The sealing plates 20 face each other in the first direction X. In the following description, the sealing plate 20 on one side X1 of the first direction X will be referred to as the first sealing plate 20A, and the sealing plate 20 on the other side X2 of the first direction X will be referred to as the second sealing plate 20B. The material of each sealing plate 20 is preferably the same type of metal material (aluminum, aluminum alloy, iron, iron alloy, etc.) as the case body 10.

[0014] At least one of the pair of sealing plates 20 (the first sealing plate 20A in FIG. 1) has a liquid inlet 22 and a sealing plug 24. As shown in FIGS. 3 and 4, the liquid inlet 22 is an opening that penetrates the first sealing plate 20A. In manufacturing the secondary battery 1, an electrolyte is injected into the battery case 70 through the liquid inlet 22. As shown in FIG. 4, in this embodiment, the electrolyte is injected in a state in which the secondary battery 1 is placed so that the first sealing plate 20A having the liquid inlet 22 is positioned upward in the direction of gravity. Therefore, after injection, the electrolyte falls due to gravity from one side X1 to the other side X2 of the first direction X. As a result, the electrolyte is supplied to the electrode body 30 inside the battery case 70. Then, after the electrolyte is injected, the liquid inlet 22 is sealed with the sealing plug 24. This prevents the electrolyte from leaking. In this embodiment, the positive electrode terminal 50 is provided at the center in the opposing direction (third direction Z) of the first side surfaces 12a, 12b of the case body 10. To avoid interference with this positive electrode terminal 50, the liquid injection hole 22 in this embodiment is formed at one end of the first sealing plate 20A in the opposing direction (the other side Z2 in the third direction Z).

[0015] As shown in FIGS. 1 and 2, a positive electrode terminal 50 is attached to the first sealing plate 20A. As described above, the positive electrode terminal 50 is provided at the center of the first side surfaces 12a and 12b of the case body 10 in the opposing direction (third direction Z). The positive electrode terminal 50 includes a positive electrode external terminal 52 and a positive electrode internal terminal 54. As shown in FIG. 4, the positive electrode external terminal 52 penetrates the first sealing plate 20A and is exposed to the outside of the battery case 70. The positive electrode internal terminal 54 is housed inside the battery case 70. The positive electrode internal terminal 54 is connected to the electrode tab 30t (positive electrode tab 32t) of the electrode assembly 30. In this specification, components that form a conductive path from the electrode assembly 30 inside the battery case 70 to the external terminal (positive electrode external terminal 52) outside the battery case 70 are collectively referred to as "internal conductive members." In the secondary battery 1 according to this embodiment, the positive electrode internal terminal 54 and the positive electrode tab 32t constitute an internal conductive member A1 on the positive electrode side.

[0016] On the other hand, a negative electrode terminal 60 is attached to the second sealing plate 20B. As shown in FIG. 3, the negative electrode terminal 60 is also provided in the center in the opposing direction (third direction Z). The negative electrode terminal 60 includes a negative electrode external terminal 62 and a negative electrode internal terminal 64. The negative electrode external terminal 62 penetrates the second sealing plate 20B and is exposed to the outside of the battery case 70. The negative electrode internal terminal 64 is housed inside the battery case 70. This negative electrode internal terminal 64 is connected to the negative electrode tab 34t of the electrode body 30. The negative electrode side internal conductive member A2 is composed of the negative electrode internal terminal 64 and the negative electrode tab 34t.

[0017] (3) Electrode body The electrode assembly 30 is a power-generating element of the secondary battery 1. As shown in FIG. 3, the electrode assembly 30 is housed inside a battery case 70. Specifically, the electrode assembly 30 is disposed in the center in the first direction X so as to be located between a pair of sealing plates 20. The electrode assembly 30 in this embodiment also includes a sheet-shaped positive electrode 32, a sheet-shaped negative electrode 34, and a separator 36 (see FIG. 5). The positive electrode 32 includes a positive electrode core 32a that is a conductive metal foil, and a positive electrode active material layer 32b that is applied to the surface of the positive electrode core 32a. A positive electrode tab 32t that exposes the positive electrode core 32a is provided on a side edge portion of the positive electrode 32 on one side X1 in the first direction X. The negative electrode 34 is an electrode that faces the positive electrode 32. The negative electrode 34 includes a negative electrode core 34a that is a conductive metal foil, and a negative electrode active material layer 34b that is applied to the surface of the negative electrode core 34a. A negative electrode tab 34t, from which the negative electrode core 34a is exposed, is provided on a side edge portion on the other side X2 in the first direction X of the negative electrode 34. The separator 36 is an insulating sheet interposed between the positive electrode 32 and the negative electrode 34. Note that the materials used for each member of the electrode assembly 30 may be any conventionally known materials that can be used in general secondary batteries, without any particular restrictions.

[0018] The electrode assembly 30 according to this embodiment is a wound electrode assembly. The wound electrode assembly 30 is formed by winding a laminate in which a positive electrode 32, a negative electrode 34, and a separator 36 are stacked. Permeation regions 30a and 30b are formed on both side surfaces of the wound electrode assembly 30 in the first direction X, exposing the space between the positive electrode 32 and the negative electrode 34 (the interior of the electrode assembly 30) to the outside. Specifically, a first permeation region 30a is formed on one side surface X1 of the electrode assembly 30 in the first direction X. Furthermore, a second permeation region 30b is formed on the other side surface X2 of the electrode assembly 30 in the first direction X. The electrolyte injected into the battery case 70 permeates into the electrode assembly 30 through the permeation regions 30a and 30b. As shown in FIG. 4, the electrode assembly 30 according to this embodiment is accommodated in the battery case 70 so that the first permeation region 30a and the liquid inlet 22 face each other. This allows the electrolyte solution injected through the liquid inlet 22 to easily permeate into the electrode assembly 30. On the other hand, the permeation regions 30a, 30b have lower strength than other parts of the electrode assembly 30 because the ends of the positive electrode 32 and the negative electrode 34 are exposed to the outside. Therefore, if the first permeation region 30a and the liquid inlet 22 were directly opposed to each other, the electrode assembly 30 might be deformed by the liquid pressure during liquid injection. In contrast, in the secondary battery 1 according to this embodiment, a partition portion 43 of the first spacer 40A (described below) is interposed between the permeation region 30a of the electrode assembly 30 and the liquid inlet 22 of the first sealing plate 20A. This prevents deformation of the electrode assembly 30 due to water pressure during liquid injection.

[0019] (4) Electrolyte Although not shown in the figure, the electrolyte is contained inside the battery case 70. The components of the electrolyte can be any that can be used in general secondary batteries, without any particular restrictions. As described above, the electrolyte permeates into the inside of the electrode assembly 30 through the permeation regions 30a, 30b of the wound electrode assembly 30. Note that a portion of the electrolyte may be present outside the electrode assembly (between the electrode assembly 30 and the battery case 70) as surplus electrolyte. This allows the electrolyte to be replenished into the electrode assembly 30 when the electrolyte in the electrode assembly 30 becomes insufficient due to decomposition of the electrolyte or the like.

[0020] (5) Spacer The spacer 40 is disposed in at least one of the spaces between the sealing plate 20 and the electrode assembly 30. As shown in FIG. 3, in the secondary battery 1 according to this embodiment, a first spacer 40A is disposed between the first sealing plate 20A and the electrode assembly 30. A second spacer 40B is disposed between the second sealing plate 20B and the electrode assembly 30. This prevents electrical conduction between the electrode assembly 30 and the sealing plate 20. The spacer 40 also restricts movement of the electrode assembly 30 in the first direction X. This prevents damage to the electrode assembly 30 (e.g., the electrode tab 30t). The material of the spacer 40 can be any insulating resin (such as polyamide resin) that can be used in general secondary batteries, without any particular restrictions.

[0021] The detailed structure of the first spacer 40A will be described below. As shown in FIGS. 4 and 6, the first spacer 40A (spacer 40) includes a pair of first wall portions 41, a pair of second wall portions 42, and a partition portion 43. The first wall portions 41 are portions that extend along at least a portion of the pair of first side surfaces 14a, 14b of the case body 10. Specifically, the first wall portions 41 are formed at both ends of the first spacer 40A in the third direction Z. As shown in FIG. 4, each of the first wall portions 41 extends upright toward one side X1 of the first direction X so as to extend along a portion (end portion on the one X1 side) of the first side surfaces 14a, 14b in the first direction X. Although not shown, each of the first wall portions 41 extends continuously along the entire area of ​​the first side surfaces 14a, 14b in the second direction Y shown in FIG. 1.

[0022] Next, the second wall portion 42 is a portion that is aligned with at least a portion of the pair of second side surfaces 16a, 16b of the case body 10. Specifically, as shown in FIG. 6, the second wall portion 42 is formed at both end portions of the first spacer 40A in the second direction Y. Each second wall portion 42 stands toward one side X1 of the first direction X so as to be aligned with a portion (the end portion on the one X1 side) of the second side surfaces 16a, 16b of the case body 10 in the first direction X. The second wall portion 42 on the one Y1 side of the second direction Y extends continuously along the third direction Z. Meanwhile, the first spacer 40A according to this embodiment has a passage space 49 formed therein for allowing the internal conductive member A1 to pass through. Therefore, the second wall portion 42 on the other side Y2 of the second direction Y is discontinued in a region including the center portion in the third direction Z.

[0023] As shown in FIG. 4, the partition portion 43 is a plate-like member extending along the opposing direction of the pair of first side surfaces 14a, 14b (third direction Z) so as to be interposed between the electrode body 30 and the sealing plate 20. The partition portion 43 is supported by a first wall portion 41 and a second wall portion 42. Specifically, both ends of the partition portion 43 in the third direction Z are connected to the lower end of the first wall portion 41. Furthermore, both ends of the partition portion 43 in the second direction Y are connected to the lower end of the second wall portion 42. As described above, a passage space 49 is formed in the first spacer 40A. Therefore, the partition portion 43 is divided in a region including a central portion in the third direction Z. In the following description, the partition portion 43 on one side Z1 in the third direction Z will be referred to as the "first partition portion 43a," and the partition portion 43 on the other side Z2 will be referred to as the "second partition portion 43b." The first partition portion 43a and the second partition portion 43b are bridged by the second wall portion 42 on one side Y1 in the second direction Y and the liquid flow path 48.

[0024] Furthermore, the first spacer 40A according to this embodiment has a plurality of openings 43c penetrating the partition 43. As shown in FIG. 6, these openings 43c are formed in both the first partition 43a and the second partition 43b. A portion of the electrolyte solution injected into the battery case 70 passes through these openings 43c and falls downward in the direction of gravity (the other side X2 of the first direction X). This makes it easier to uniformly supply the electrolyte solution to the electrode assembly 30.

[0025] As shown in FIG. 4 , in the secondary battery 1 according to this embodiment, the liquid inlet 22 of the sealing plate 20 and the partition 43 of the first spacer 40A face each other with a certain gap between them. The partition 43 is provided with a diffusion member 44 that diffuses the electrolyte solution injected from the liquid inlet 22 along the partition 43. This reduces the time required for the electrolyte solution to uniformly penetrate into the electrode assembly 30. Specifically, as indicated by arrow E in FIG. 4 , the electrolyte solution injected from the liquid inlet 22 falls downward in the direction of gravity (the other side X2 of the first direction X) and comes into contact with the diffusion member 44. The diffusion member 44 then redirects the flow of the electrolyte solution so that it flows along the partition 43. The partition 43 extends in the opposing direction of the first side surfaces 14a and 14b (i.e., the third direction Z). Therefore, by diffusing the electrolyte solution along the partition portion 43, the electrolyte solution can be supplied over a wide area along the opposing direction (third direction Z) of the case body 10, thereby shortening the time required for the electrolyte solution to uniformly penetrate into the inside of the electrode body 30.

[0026] The diffusion member 44 in this embodiment includes a third wall portion 44a and an inclined surface 44b. The third wall portion 44a is a plate-like member extending from the partition portion 43 toward the liquid inlet 22. The inclined surface 44b slopes downward from an upper end portion 44a1 of the third wall portion 44a toward the partition portion 43. More specifically, the diffusion member 44 in this embodiment is a member having a vertical triangular cross section, with the inclined surface 44b sloping downward toward the first side surface 14b farther from the liquid inlet 22 (in other words, toward the other side Z2 of the third direction Z). The diffusion member 44 can favorably diffuse the electrolyte toward a position farther from the liquid inlet 22. The inclination angle of the inclined surface 44b is preferably 10° to 60° (more preferably 20° to 50°, and particularly preferably 40° to 50°). This allows the electrolyte to be more efficiently diffused toward the first side surface 14b. The inclination angle here refers to the acute angle formed between the partition 43 and the inclined surface 44b. The diffusion member 44 is preferably provided so that the inclined surface 44b faces the liquid injection hole 22. This allows the electrolyte solution dropping from the liquid injection hole 22 to appropriately come into contact with the inclined surface 44b.

[0027] 6, the diffusion member 44 extends from one of the pair of second wall portions 42 to the other. In other words, the diffusion member 44 is formed continuously along the second direction Y so as to face the first wall portion 41. This allows the electrolyte to be diffused more efficiently.

[0028] As described above, the secondary battery 1 according to this embodiment includes an internal conductive member A1 (positive electrode internal terminal 54 and electrode tab 30t) that forms a conductive path from the electrode assembly 30 inside the battery case 70 to an external terminal (positive electrode external terminal 52) outside the battery case 70 (see FIG. 4). In this case, a passing space 49 that allows the internal conductive member A1 to pass through is formed in the first spacer 40A. This makes it possible to easily form a conductive path from the electrode assembly 30 to the positive electrode external terminal 52 even when the first spacer 40A is interposed between the first sealing plate 20A and the electrode assembly 30. As shown in FIG. 6, the passing space 49 in this embodiment is a notch formed in the partition 43 and one second wall 42 (on the other Y2 side in the second direction Y). That is, the partition 43 and one second wall 42 are separated by the passing space 49 in a region including the center in the third direction Z. In the first spacer 40A having such a configuration, part of the electrolyte solution tends to fall downward in the direction of gravity (the other side X2 of the first direction X) through the passage space 49. This makes it easier for the electrolyte solution to be supplied to the electrode assembly 30.

[0029] As described above, in the first spacer 40A of the present embodiment, the passing spaces 49 are formed in a region including the central portion in the third direction Z. In contrast, the diffusion member 44 is configured to diffuse the electrolyte injected from the injection hole 22 toward the passing spaces 49. Specifically, the diffusion member 44 has an inclined surface 44b that slopes downward toward the passing spaces 49. This allows the electrolyte to be efficiently supplied to the electrode assembly 30 through the passing spaces 49.

[0030] Furthermore, the first spacer 40A in this embodiment has a liquid flow path 48 that bridges the partitions 43 (the first partition 43a and the second partition 43b) that face each other across the passage space 49. The liquid flow path 48 is a rod-shaped member extending in the third direction Z along the second wall 42. An end 48a of the liquid flow path 48 on one side Z1 of the third direction Z is connected to the first partition 43a. An end 48b of the liquid flow path 48 on the other side Z2 of the third direction Z is connected to the second partition 43b. The first spacer 40A configured as described above can more efficiently diffuse the electrolyte throughout the entire area in the third direction Z. Specifically, as shown in FIG. 4, the electrolyte injected through the liquid injection hole 22 falls onto the first partition 43a. At this time, a portion of the electrolyte falls from the opening 43c of the first partition 43a. This allows the electrolyte to be supplied to the end on one side Z1 of the third direction Z. Furthermore, a portion of the electrolyte solution is diffused toward the other side Z2 of the third direction Z by the diffusion member 44. Then, a portion of the diffused electrolyte solution falls from the passage space 49. This allows the electrolyte solution to be supplied to the center portion in the third direction Z. The remaining electrolyte solution travels along the liquid flow path 48 to reach the second partition portion 43b and falls from the opening 43c of the second partition portion 43b. This allows the electrolyte solution to be supplied to the end portion on the other side Z2 of the third direction Z. As described above, the first spacer 40A in this embodiment has the liquid flow path 48, and therefore can more efficiently diffuse the electrolyte solution throughout the entire area in the third direction Z.

[0031] Furthermore, in the first spacer 40A of this embodiment, as shown in FIG. 4, a fourth wall portion 46 is provided at an end 43a1 of the first partition portion 43a adjacent to the passage space 49, facing the first sealing plate 20A (i.e., one side X1 of the first direction X). This configuration prevents most of the electrolyte solution diffused by the diffusion member 44 toward the other side Z2 of the third direction Z from dropping from the passage space 49. This increases the amount of electrolyte solution supplied to the second partition portion 43b via the liquid flow path 48, making it easier to diffuse a sufficient amount of electrolyte solution toward the end on the other side Z2 of the third direction Z. Furthermore, as shown in FIG. 6, the liquid flow path 48 preferably does not have a wall portion at the side edge portion adjacent to the passage space 49. This allows a portion of the electrolyte solution flowing through the liquid flow path 48 to drop, thereby enabling the electrolyte solution to be more uniformly dispersed.

[0032] The first spacer 40A in this embodiment has been described above. The first spacer 40A configured as described above includes a partition 43 extending in the third direction Z and a diffusion member 44 that diffuses the electrolyte solution along the partition 43. This allows the electrolyte solution to be supplied over a wide area along the third direction Z, making it easier for the electrolyte solution to uniformly penetrate into the electrode body 30. In the secondary battery 1 according to this embodiment, a spacer 40 (second spacer 40B) is also arranged on the other side X2 of the first direction X. This second spacer 40B has substantially the same structure as the first spacer 40A, and therefore a detailed description of the structure will be omitted.

[0033] <Other embodiments> The first embodiment of the technology disclosed herein has been described above. In the secondary battery disclosed herein, it is sufficient that a diffusion member that diffuses the electrolyte solution along the partition is formed on the spacer. Other configurations are not limited to those of the first embodiment described above. Other embodiments of the technology disclosed herein will be described below.

[0034] For example, the diffusion member 44 of the secondary battery 1 according to the first embodiment includes a third wall portion 44a and an inclined surface 44b. However, the diffusion member need only be able to diffuse the electrolyte solution along the opposing direction, and is not limited to the shape of the first embodiment. For example, the diffusion member 44 of the secondary battery 1A shown in FIG. 7 includes an inclined surface 44b that slopes downward from the first wall portion 41 toward the partition portion 43. Even when a diffusion member 44 without a third wall portion is used in this way, the electrolyte solution can be diffused along the opposing direction (third direction Z).

[0035] 6, the diffusion member 44 in the first embodiment is formed continuously along the second direction Y so as to face the first wall portion 41. However, the length of the diffusion member 44 in the second direction Y is not particularly limited. For example, the diffusion member may be formed only directly below the injection hole. A diffusion member with such a configuration can also sufficiently diffuse the injected electrolyte.

[0036] Furthermore, the passage space 49 of the spacer 40 in the first embodiment is a notch formed in the partition portion 43. However, the spacer is not limited to the notch-shaped passage space of the first embodiment as long as it has a space that allows the internal conductive member (internal terminal or electrode tab) to pass through. For example, the secondary battery 1B shown in FIG. 8 uses a positive electrode internal terminal 54 having a thin rod-shaped portion 54a extending along the first direction X. When such a configuration is adopted, a small opening through which the rod-shaped portion 54a of the positive electrode internal terminal 54 can be inserted may be formed as the passage space 49. When such a configuration is adopted, the positive electrode internal terminal 54 and the electrode tab 30t are connected below the spacer 40. Furthermore, when the passage space 49 is a small opening, the partition portion 43 is not divided, and therefore the electrolyte can be easily diffused throughout the entire area in the third direction Z without forming the liquid flow path 48 shown in FIG. 6.

[0037] Furthermore, the spacer 40 in the first embodiment has a liquid flow path 48 that bridges the first partition portion 43a and the second partition portion 43b. However, the liquid flow path is not an essential requirement for the secondary battery disclosed herein. For example, as shown in FIG. 8, if the passage space 49 is a minute opening, the partition portion 43 is not divided, and the electrolyte solution can be easily diffused throughout the entire area in the third direction Z without forming the liquid flow path 48 as shown in FIG. 6. Furthermore, the first spacer may not have a liquid flow path, and the first partition portion and the second partition portion may be completely separated. The diffusion member of the first spacer configured as described above is preferably configured to diffuse the electrolyte solution toward the inner wall (typically, the second side surface) of the case body. This allows the electrolyte solution to diffuse along the inner wall of the case body, allowing the electrolyte solution to be supplied from the first partition portion to the second partition portion across the passage space.

[0038] Furthermore, in the secondary battery 1 according to the first embodiment, a spacer having substantially the same structure as the first spacer 40A is used as the second spacer 40B. However, since the second spacer does not face the injection hole, it does not affect the penetration efficiency of the electrolyte. Therefore, a spacer without a diffusion member may be used as the second spacer. Furthermore, the secondary battery disclosed herein does not need to have a second spacer as long as electrical conduction between the sealing plate and the electrode assembly can be suppressed. For example, by attaching an insulating film to the inner wall of the second sealing plate, electrical conduction between the sealing plate and the electrode assembly can be suppressed without using a second spacer.

[0039] While specific examples of the technology disclosed herein have been described in detail above, these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and alterations of the specific examples exemplified above.

[0040] The technology disclosed herein includes the following items 1 to 11. The following items 1 to 11 are not limited to the above-described embodiment.

[0041] <Item 1> a rectangular cylindrical case body having a pair of openings at both ends; a pair of sealing plates that close the pair of openings to form a battery case; an electrode assembly housed inside the battery case; an electrolyte solution contained inside the battery case; a spacer disposed in at least one of the spaces between the sealing plate and the electrode body; It has The square cylindrical case body is A pair of first side surfaces that are rectangular plate-shaped portions facing each other; a pair of second side surfaces that are rectangular plate-like portions that extend from an edge of one of the first side surfaces toward an edge of the other of the first side surfaces and face each other; Equipped with At least one of the pair of sealing plates is a liquid injection hole penetrating the sealing plate; a sealing plug that seals the liquid inlet; Equipped with The spacer is a pair of first wall portions along at least a portion of the pair of first side surfaces of the case body; a pair of second wall portions along at least a portion of the pair of second side surfaces of the case body; a partition portion that is a plate-like member extending along the opposing direction of the pair of first side surfaces so as to be interposed between the electrode body and the sealing plate, and that is supported by the first wall portion and the second wall portion; Equipped with the liquid injection hole and the partition portion face each other with a certain space therebetween, and a diffusion member that diffuses the electrolyte injected from the liquid injection hole along the partition portion is provided on the partition portion.

[0042] <Item 2> The diffusing member is a third wall portion extending from the partition portion toward the liquid injection hole; an inclined surface that slopes downward from the upper end of the third wall portion toward the partition portion; 2. The nonaqueous electrolyte secondary battery according to item 1,

[0043] <Item 3> 3. The nonaqueous electrolyte secondary battery according to claim 2, wherein the diffusion member is provided so that the inclined surface faces the liquid injection hole.

[0044] <Item 4> 4. The nonaqueous electrolyte secondary battery according to any one of items 1 to 3, wherein the diffusion member extends from one of the pair of second wall portions to the other so as to face the first wall portion.

[0045] <Item 5> an internal conductive member that forms a conductive path from the electrode body inside the battery case to an external terminal outside the battery case; 5. The nonaqueous electrolyte secondary battery according to any one of items 1 to 4, wherein the spacer has a passage space through which the internal conductive member passes.

[0046] <Item 6> the passage space is formed in a region including a central portion of the spacer in a direction in which the pair of first side surfaces face each other, the liquid injection hole is formed at one end of the sealing plate in the opposing direction, 6. The nonaqueous electrolyte secondary battery according to claim 5, wherein the diffusion member is configured to diffuse the electrolyte toward the passage space.

[0047] <Item 7> 7. The nonaqueous electrolyte secondary battery according to item 5 or 6, wherein the passage space is a notch formed in the partition.

[0048] <Item 8> 8. The nonaqueous electrolyte secondary battery according to any one of items 5 to 7, wherein the spacer has a liquid flow path that bridges the partition portions that face each other across the passage space.

[0049] <Item 9> Item 9. The nonaqueous electrolyte secondary battery according to any one of items 5 to 8, wherein a fourth wall portion erected toward the sealing plate is provided at an end of the partition portion adjacent to the passage space.

[0050] <Item 10> The electrode body is a sheet-like positive electrode; a sheet-like negative electrode facing the positive electrode; a separator interposed between the positive electrode and the negative electrode; It has 10. The nonaqueous electrolyte secondary battery according to any one of items 1 to 9, wherein the electrode assembly is housed in the case such that a permeation region between the positive electrode and the negative electrode, which is exposed to the outside, faces the liquid injection hole.

[0051] <Item 11> 11. The nonaqueous electrolyte secondary battery according to any one of items 1 to 10, wherein the spacer has a plurality of openings penetrating the partition portion. [Explanation of symbols]

[0052] 1, 1A, 1B secondary battery 10 Case body 12 Opening 14a, 14b First side 16a, 16b 2nd side 20 Sealing plate 22 Liquid injection hole 24 Sealing plug 30 Electrode body (wound electrode body) 40 spacer 41 1st wall 42 2nd wall section 43 Partition 43c aperture 44 Diffusion element 44a Third wall 44b Slope 46 4th wall 48 Liquid flow path 49 Passage space 50 Positive terminal 60 Negative terminal 70 Battery Case

Claims

1. a rectangular cylindrical case body having a pair of openings at both ends; a pair of sealing plates that close the pair of openings to form a battery case; an electrode assembly housed inside the battery case; an electrolyte solution contained inside the battery case; a spacer disposed in at least one of the spaces between the sealing plate and the electrode body; It has The square cylindrical case body is a pair of first side surfaces that are rectangular plate-like portions facing each other; a pair of second side surfaces that are rectangular plate-like portions that extend from an edge of one of the first side surfaces toward an edge of the other of the first side surfaces and face each other; Equipped with At least one of the pair of sealing plates is a liquid injection hole penetrating the sealing plate; a sealing plug that seals the liquid inlet; Equipped with The spacer is a pair of first wall portions along at least a portion of the pair of first side surfaces of the case body; a pair of second wall portions along at least a portion of the pair of second side surfaces of the case body; a partition portion that is a plate-like member extending along the opposing direction of the pair of first side surfaces so as to be interposed between the electrode body and the sealing plate, and that is supported by the first wall portion and the second wall portion; Equipped with the liquid injection hole and the partition portion face each other with a certain space therebetween, and a diffusion member that diffuses the electrolyte injected from the liquid injection hole along the partition portion is provided on the partition portion.

2. The diffusing member is a third wall portion extending from the partition portion toward the liquid injection hole; an inclined surface that slopes downward from an upper end of the third wall portion toward the partition portion; The nonaqueous electrolyte secondary battery according to claim 1 , comprising:

3. 3. The nonaqueous electrolyte secondary battery according to claim 2, wherein the diffusion member is provided so that the inclined surface faces the liquid injection hole.

4. 2 . The nonaqueous electrolyte secondary battery according to claim 1 , wherein the diffusion member extends from one of the pair of second walls to the other so as to face the first wall.

5. an internal conductive member that forms a conductive path from the electrode body inside the battery case to an external terminal outside the battery case; 2. The nonaqueous electrolyte secondary battery according to claim 1, wherein the spacer has a passage space for allowing the internal conductive member to pass therethrough.

6. the passage space is formed in a region including a central portion of the spacer in a direction in which the pair of first side surfaces face each other, the liquid injection hole is formed at one end of the sealing plate in the opposing direction, 6. The nonaqueous electrolyte secondary battery according to claim 5, wherein the diffusion member is configured to diffuse the electrolyte toward the passage space.

7. 6. The nonaqueous electrolyte secondary battery according to claim 5, wherein the passage space is a notch formed in the partition portion and one of the pair of second wall portions.

8. 6. The nonaqueous electrolyte secondary battery according to claim 5, wherein the spacer has a liquid flow path bridging the partition portions that face each other across the passage space.

9. 6. The nonaqueous electrolyte secondary battery according to claim 5, wherein a fourth wall portion is provided at an end of the partition portion adjacent to the passage space, the fourth wall portion being erected toward the sealing plate.

10. The electrode body is a sheet-like positive electrode; a sheet-like negative electrode facing the positive electrode; a separator interposed between the positive electrode and the negative electrode; It has 2. The nonaqueous electrolyte secondary battery according to claim 1, wherein the electrode assembly is housed in the case such that a permeation region between the positive electrode and the negative electrode, which is exposed to the outside, faces the liquid injection hole.

11. 2. The nonaqueous electrolyte secondary battery according to claim 1, wherein the spacer has a plurality of openings penetrating the partition portion.

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