Nonaqueous electrolyte secondary battery

Abstract

To suppress the deformation of a spacer in a liquid injection step.SOLUTION: A secondary battery 1 disclosed herein includes a case body 10, a first sealing plate, a second sealing plate 20B, an electrode body 30, and an electrolytic solution. A second spacer 40B supporting the electrode body 30 from below at an injection time of the electrolytic solution is arranged in a space between the second sealing plate 20B and the electrode body 30. The second spacer 40B includes a pair of first wall parts 41 and a pair of second wall parts 42. The second spacer 40B is configured to make a load bearing capacity of the second wall part 42 be lower than a load bearing capacity of the first wall part 41. By doing this, a deformation pattern of the second spacer 40B can be controlled so as to cause a deformation in which the second wall part 42 works as a starting point. The second spacer 40 includes a rib to bridge the pair of second wall parts 42. By doing this, the second wall part 42 can be reinforced, so that the deformation of the second spacer 40 can be suppressed.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 has an opening (filling hole) for pouring the electrolyte. In addition, in this type of secondary battery, a spacer may be disposed between the battery case and the electrode assembly. This restricts movement of the electrode assembly within the battery case, thereby preventing damage to the electrode assembly during transportation. An example of a secondary battery having such a spacer is disclosed in Patent Document 1. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special Publication No. 2023-502461 Summary of the Invention [Problem to be solved by the invention]

[0004] In the manufacture of secondary batteries, a liquid injection process is carried out in which an electrolyte injection hole is positioned above the direction of gravity and an electrolyte is injected through the liquid injection hole. Depending on the structure of the secondary battery, a spacer may be positioned below the electrode assembly during this liquid injection process. In this case, the weight of the electrode assembly may cause deformation of the spacer. The technology disclosed herein has been developed to solve this problem and aims to suppress deformation of the spacer during the liquid injection process. [Means for solving the problem]

[0005] 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 close the pair of openings to form the battery case, an electrode assembly housed inside the battery case, and an electrolyte housed inside the battery case. The rectangular tubular case body has 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. The pair of sealing plates includes a first sealing plate having a liquid injection hole for injecting the electrolyte into the battery case, and a second sealing plate that is positioned below in the direction of gravity when the electrolyte is injected. In addition, a second spacer is positioned in the space between the second sealing plate and the electrode assembly to support the electrode assembly from below when the electrolyte is injected. The second 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 in 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. The second spacer of the nonaqueous electrolyte secondary battery disclosed herein is configured so that the load-bearing capacity of the second walls is lower than that of the first wall, and includes a rib bridging the pair of second walls.

[0006] The second spacer of the secondary battery disclosed herein is a box-shaped spacer having a pair of first wall portions and a pair of second wall portions. The second wall portions of the second spacer are configured to have a lower load-bearing capacity than the first wall portions. This makes it possible to control the deformation pattern of the second spacer when the weight of the electrode assembly is applied so that deformation originates from the second wall portions. The second spacer of the secondary battery disclosed herein also has a rib bridging the pair of second wall portions. This reinforces the second wall portions, which are the deformation origin, and therefore makes it possible to suppress deformation of the second spacer during the liquid injection process. [Brief explanation of the drawings]

[0007] [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 secondary battery in the liquid injection step. [Figure 4] FIG. 4 is an enlarged cross-sectional view schematically showing the vicinity of the second spacer in FIG. [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 second spacer of a secondary battery according to one embodiment. [Figure 7] FIG. 7 is an enlarged cross-sectional view schematically showing the vicinity of a second spacer in a liquid injection step of a secondary battery according to another embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] 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.

[0009] First Embodiment An embodiment of the nonaqueous electrolyte secondary battery disclosed herein will be described below. FIG. 1 is a perspective view schematically showing 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 showing the secondary battery in a liquid injection step. FIG. 4 is an enlarged cross-sectional view schematically showing the vicinity of the second spacer in FIG. 3. FIG. 5 is a perspective view schematically showing an electrode body of the secondary battery according to this embodiment. FIG. 6 is a perspective view schematically showing the second 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 the first direction, the second direction, and the third direction, respectively.

[0010] 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.

[0011] (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 referred to as the "facing direction of the first side surfaces." Meanwhile, 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. In this specification, the direction in which the pair of second side surfaces 16a, 16b face each other (i.e., the second direction Y in the drawings) is referred to as the "facing direction of the second side surfaces." The second side surfaces 16a, 16b also extend along the first direction X. As shown in FIGS. 1 and 2, the case body 10 in this embodiment is a rectangular parallelepiped member. The first side surfaces 14a, 14b form narrow sides of the case body 10. The second side surfaces 16a, 16b form wide sides of the case body 10. In other words, the dimension of the second side surfaces 16a, 16b in the third direction Z is longer than the dimension of the first side surfaces 14a, 14b in the second direction Y.

[0012] The 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. 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 sealing plates 20 are rectangular plate-like members whose dimension in the third direction Z is longer than their dimension in the second direction Y. The battery case 70 is constructed by sealing the openings 12 of the case body 10 with these sealing plates 20. The material of each sealing plate 20 is preferably the same type of metal material as the case body 10 (aluminum, aluminum alloy, iron, iron alloy, etc.).

[0014] As shown in FIGS. 1 and 2 , the pair of 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 first sealing plate 20A has a liquid injection hole 22 for injecting an electrolyte into the battery case 70. The liquid injection hole 22 is an opening that penetrates the first sealing plate 20A. In manufacturing the secondary battery 1, the electrolyte is injected into the battery case 70 through the liquid injection hole 22. After the electrolyte is injected, the liquid injection hole 22 is sealed with a sealing plug 24. Note that, as shown in FIG. 3 , in this embodiment, the electrolyte is injected while the secondary battery 1 is installed so that the first sealing plate 20A having the liquid injection hole 22 is positioned upward in the direction of gravity. That is, when the liquid injection step is performed, the second sealing plate 20B is positioned downward in the direction of gravity.

[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 in the center of the first side surfaces 12a and 12b of the case body 10 in the opposing direction (third direction Z). To avoid interference with the positive electrode terminal 50, in the secondary battery according to this embodiment, a liquid injection hole 22 is formed at one end of the first sealing plate 20A in the opposing direction (the other end Z2 in the third direction Z). The positive electrode terminal 50 also includes a positive electrode external terminal 52 and a positive electrode internal terminal 54. As shown in FIG. 3, 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, the components that form the conductive path from the electrode body 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 the "internal conductive member." In the secondary battery 1 according to this embodiment, the positive electrode internal terminal 54 and the positive electrode tab 32t form the positive electrode side internal conductive member A1.

[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 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. Therefore, 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. As shown in FIG. 5, the electrode assembly 30 includes a sheet-shaped positive electrode 32, a sheet-shaped negative electrode 34, and a separator 36. The positive electrode 32 includes a positive electrode core 32a that is a conductive metal foil and a positive electrode active material layer 32b 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. On the other hand, the negative electrode 34 is an electrode facing 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 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. 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. 3, 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 injected through the injection hole 22 to easily permeate into the inside of the electrode body 30.

[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 As shown in FIG. 3, in the secondary battery 1 according to this embodiment, a spacer 40 is disposed in the space between the sealing plate 20 and the electrode assembly 30. Specifically, 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. These spacers 40 prevent 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] As described above, in the liquid injection step of this embodiment, the secondary battery 1 is placed so that the first sealing plate 20A having the liquid injection hole 22 is positioned upward in the direction of gravity (see FIG. 3). Therefore, when the electrolyte is injected, the second spacer 40B is positioned downward in the direction of gravity so as to support the electrode assembly 30 from below. In contrast, the second spacer 40B is configured to be able to suppress deformation even when the weight of the electrode assembly 30 is applied during the liquid injection step. This second spacer 40B includes a pair of first wall portions 41, a pair of second wall portions 42, a partition portion 43, and a rib 45. The specific structure of the second spacer 40B will be described below.

[0022] As shown in FIG. 4, 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 end portions of the second spacer 40B in the third direction Z. Each of the first wall portions 41 extends upright toward the other side X2 in the first direction X so as to extend along a portion (the end portion on the other side X2) of the first side surfaces 14a, 14b in the first direction X. Furthermore, 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.

[0023] Next, the second wall portions 42 are portions that extend along at least a portion of the pair of second side surfaces 16a, 16b of the case body 10. These second wall portions 42 extend along the second side surfaces 16a, 16b, which are the wider surfaces of the case body 10. Therefore, the length of the second wall portions 42 in the third direction Z is longer than the length of the first wall portion 41 in the second direction Y. Also, as shown in FIG. 6, the second wall portions 42 are formed at both ends of the second spacer 40B in the second direction Y. For ease of explanation, hereinafter, the second wall portion 42 formed on one side Y1 in the second direction Y will be referred to as the "rear second wall portion 42R," and the second wall portion 42 formed on the other side Y2 in the second direction Y will be referred to as the "front second wall portion 42F." The rear second wall portion 42R extends continuously along the third direction Z. On the other hand, the second spacer 40B according to this embodiment has a passage space 49 formed therein for allowing the negative-electrode internal conductive member A2 to pass therethrough (see FIG. 4). For this reason, the front second wall portion 42F is discontinued in a region including the center in the third direction Z, as shown in FIG. 6. Each second wall portion 42 extends upright toward the other side X2 of the first direction X so as to align with a portion (the end portion on the other X2 side) of the second side surfaces 16a, 16b of the case body 10 in the first direction X.

[0024] 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 (the 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. As shown in FIG. 6, 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. Furthermore, as described above, a passage space 49 is formed in the second spacer 40B. 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 43a and the second partition 43b are bridged by a connecting portion 48 to the second wall 42 on one side Y1 in the second direction Y. The second spacer 40B according to this embodiment has a plurality of openings 43c penetrating the partition 43. The openings 43c are formed in both the first partition 43a and the second partition 43b. By forming the openings 43c in the second spacer 40B, which is disposed downward in the direction of gravity during injection, a portion of the electrolyte solution being injected can flow downward (toward the other side X2 in the first direction X) from the second spacer 40B. This prevents the electrolyte solution from overflowing from the injection hole 22 when the speed at which the electrolyte solution is being injected cannot keep up with the speed at which it permeates into the electrode assembly 30.

[0025] Here, the second spacer 40B in this embodiment is configured so that the load-bearing capacity of the second wall portion 42 is lower than the load-bearing capacity of the first wall portion 41. This makes it possible to control the deformation pattern of the second spacer 40B when the weight of the electrode body 30 is applied so that deformation originates from the second wall portion 42. The second spacer 40B in this embodiment is provided with a rib 45 that bridges the pair of second wall portions 42. This makes it possible to reinforce the second wall portions 42, which are the deformation origin, and therefore makes it possible to suppress deformation of the second spacer 40B during the liquid injection process. This point will be described in detail below.

[0026] (a) Decrease in the load-bearing capacity of the second wall First, the second spacer 40B in this embodiment has the following three structural features: As a result, the second wall portion 42 of the second spacer 40B has a lower load-bearing capacity than the first wall portion 41.

[0027] (a-1) Wall thickness First, in this embodiment, the thickness of the second wall portion 42 is thinner than the thickness of the first wall portion 41. This relatively reduces the load-bearing capacity of the second wall portion 42, making it easier for deformation to occur starting from the second wall portion 42. Note that the "thickness of the second wall portion 42" here refers to the dimension of the second wall portion 42 in the second direction Y in FIG. 6. Furthermore, the "thickness of the first wall portion 41" refers to the dimension of the first wall portion 41 in the third direction Z. For example, the thickness of the second wall portion 42 is preferably 80% or less (more preferably 75% or less, even more preferably 60% or less, and particularly preferably 40% or less) of the thickness of the first wall portion 41. This makes it even easier for deformation to occur starting from the second wall portion 42.

[0028] The second wall portion 42 may be relatively thinner than the first wall portion 41. That is, the specific thickness of the second wall portion 42 is not particularly limited. However, the thickness of the second wall portion 42 is preferably 1.9 mm or less, more preferably 1.5 mm or less, even more preferably 1.3 mm or less, and particularly preferably 0.9 mm or less. As the thickness of the second wall portion 42 decreases, the second wall portion 42 becomes more likely to become a starting point for deformation. On the other hand, the thickness of the second wall portion 42 is preferably 0.4 mm or more, more preferably 0.5 mm or more, even more preferably 0.6 mm or more, and particularly preferably 0.7 mm or more. This prevents the second wall portion 42 from becoming more easily deformed than necessary. On the other hand, the thickness of the first wall portion 41 is preferably 0.5 mm or more, more preferably 0.6 mm or more, even more preferably 0.7 mm or more, and particularly preferably 0.8 mm or more. This prevents the first wall portion 41 from becoming a starting point for deformation. On the other hand, the upper limit of the thickness of the first wall portion 41 is preferably 2.0 mm or less, more preferably 1.6 mm or less, even more preferably 1.4 mm or less, and particularly preferably 1.0 mm or less, which can prevent a decrease in the amount of electrolyte retained in the battery case 70 due to an increase in the volume of the second spacer 40B.

[0029] (a-2) Wall length Second, in this embodiment, the length of the second wall portion 42 is longer than the length of the first wall portion 41. Here, the "length of the second wall portion 42" refers to the dimension of the second wall portion 42 in the third direction Z in FIG. 6 . Furthermore, the "length of the first wall portion 41" refers to the dimension of the first wall portion 41 in the second direction Y. In the second spacer 40B shown in FIG. 6 , the first wall portion 41 and the second wall portion 42 are mutually supported at the corner portion 47. In this case, the load-bearing capacity of the position farthest from the corner portion 47 is likely to decrease. Therefore, by making the second wall portion 42 longer than the first wall portion 41, the load-bearing capacity of the central portion of the second wall portion 42 can be reduced. As a result, when the weight of the electrode body 30 is applied to the second spacer 40B, deformation originating from the second wall portion 42 is likely to occur. The length of the second wall portion 42 is preferably 150% or more (more preferably 200% or more, even more preferably 250% or more, and particularly preferably 300% or more) of the length of the first wall portion 41. This makes it even easier for deformation to occur starting from the second wall portion 42.

[0030] The second wall portion 42 may be relatively longer than the first wall portion 41. That is, the specific length of the second wall portion 42 is not particularly limited. However, the length of the second wall portion 42 is preferably 40 mm or more, more preferably 50 mm or more, even more preferably 70 mm or more, and particularly preferably 80 mm or more. As the second wall portion 42 becomes longer, deformation originating from the second wall portion 42 becomes more likely to occur. On the other hand, the length of the second wall portion 42 is preferably 120 mm or less, more preferably 110 mm or less, even more preferably 100 mm or less, and particularly preferably 90 mm or less. This prevents the second wall portion 42 from deforming more easily than necessary. Furthermore, the length of the first wall portion 41 is preferably 40 mm or less, more preferably 35 mm or less, even more preferably 30 mm or less, and particularly preferably 25 mm or less. This prevents the first wall portion 41 from becoming a deformation origin. On the other hand, the lower limit of the length of the first wall portion 41 is not particularly limited, and may be 10 mm or more, 12 mm or more, 15 mm or more, or 20 mm or more.

[0031] (a-3) Separation of the second wall Next, the secondary battery 1 according to this embodiment includes an internal conductive member A2 (negative electrode internal terminal 64 and electrode tab 30t) that forms a conductive path from the electrode assembly 30 inside the battery case 70 to an external terminal (negative electrode external terminal 62) outside the battery case 70 (see FIG. 4 ). At this time, a passing space 49 that allows the internal conductive member A2 to pass through is formed in the second spacer 40B. This makes it possible to easily form a conductive path from the electrode assembly 30 to the negative electrode external terminal 62 even when the second spacer 40B is interposed between the second sealing plate 20B and the electrode assembly 30. Here, the passing space 49 of the second spacer 40B shown in FIG. 6 is a notch that divides one of the pair of second wall portions 42 (the front second wall portion 42F). Furthermore, the front second wall portion 42F that is divided by the passing space 49 has ends 42Fa and 42Fb adjacent to the passing space 49 that are no longer supported by the first wall portion 41. This significantly reduces the load-bearing capacity of the front second wall portion 42F at the ends 42Fa and 42Fb adjacent to the passage space 49. Therefore, when the weight of the electrode body 30 is applied to the second spacer 40B, deformation is likely to occur starting from the front second wall portion 42F.

[0032] (b) Rib As described above, the second spacer 40B in this embodiment is configured so that the load-bearing capacity of the second wall portion 42 is lower than that of the first wall portion 41. Here, the second wall portion 42 is housed in the battery case 70 so as to fit along the second side surfaces 16a, 16b of the case body 10. Therefore, when the weight of the electrode body 30 is applied to the second spacer 40B, the second wall portion 42 is deformed so as to be folded inward in the second direction Y. In response to this, the second spacer 40B in this embodiment is provided with a rib 45 that bridges the pair of opposing second wall portions 42. This rib 45 is a plate-shaped member that extends from the rear second wall portion 42R toward the front second wall portion 42F. This rib 45 can restrict deformation of the second wall portion 42 inward in the second direction Y. As described above, in the second spacer 40B of this embodiment, the deformation pattern of the second spacer 40B is controlled so that deformation originates from the second wall portion 42. The second wall portion 42, which is the deformation origin, is reinforced with the rib 45. This makes it possible to suppress deformation of the second spacer 40B during the liquid injection step.

[0033] The thickness of the rib 45 is preferably 0.6 mm or more, more preferably 0.8 mm or more, and particularly preferably 1.0 mm or more. This improves the strength of the rib 45, thereby more preferably reinforcing the second wall portion 42. The second spacer 40B made of resin shrinks a certain amount during molding. Therefore, if the rib 45 is too thick, the second wall portion 42 may be deformed by the tension caused by the shrinkage of the rib 45. From this perspective, the upper limit of the thickness of the rib 45 is preferably 2.0 mm or less, more preferably 1.5 mm or less, and particularly preferably 1.2 mm or less.

[0034] Furthermore, it is preferable that the height of the rib 45 at the portion in contact with the second wall portion 42 be 30% or more of the height of the second wall portion 42 (more preferably 50% or more, even more preferably 75% or more, and particularly preferably 90% or more). This more reliably prevents the second wall portion 42 from folding inward in the second direction Y. On the other hand, the rib 45 that protrudes above the second wall portion 42 does not contribute to improving the strength of the second wall portion 42. For this reason, it is preferable that the upper limit of the height of the rib 45 relative to the height of the second wall portion 42 be 100% or less.

[0035] As shown in FIGS. 4 and 6 , the second spacer 40B in this embodiment includes a plurality of ribs 45. This allows the second wall portion 42 to be reinforced more effectively. The plurality of ribs 45 are provided on each of a pair of partition portions 43 that face each other across the passing space 49. Specifically, a first rib 45a and a second rib 45b are provided on the first partition portion 43a. Furthermore, a third rib 45c is provided on the second partition portion 43b. This allows deformation of each of the front second wall portions 42F separated by the passing space 49 to be suppressed. Furthermore, some of the plurality of ribs 45 extend to bridge the pair of second wall portions 42 at positions adjacent to the passing space 49. Specifically, the second rib 45b and the third rib 45c extend from the ends 42Fa and 42Fb of the front second wall portion 42F on the passing space 49 side toward the rear second wall portion 42R, respectively. This makes it possible to more suitably suppress deformation of the ends 42Fa, 42Fb of the front second wall portion 42F adjacent to the passage space 49.

[0036] Furthermore, the first spacer 40A in this embodiment has a connecting portion 48 that bridges the partition portions 43 (the first partition portion 43a and the second partition portion 43b) that face each other across the passage space 49. The connecting portion 48 is a rod-shaped member extending in the third direction Z along the second wall portion 42. An end portion 48a of the connecting portion 48 on one side Z1 in the third direction Z is connected to the first partition portion 43a. An end portion 48b of the connecting portion 48 on the other side Z2 in the third direction Z is connected to the second partition portion 43b. The connecting portion 48 extends along the opposing direction of the pair of first side surfaces 14a, 14b (the first direction X) so as to be adjacent to the rear second wall portion 42R. By arranging the connecting portion 48 along the rear second wall portion 42R in this manner, the rear second wall portion 42R can be reinforced. Furthermore, the second rib 45b is adjacent to the end portion 48a on one side Z1 of the connecting portion 48. Additionally, the third rib 45c is adjacent to the end 48b on the other side Z2 of the connecting portion 48. This also makes it possible to suppress deformation of the connecting portion 48 originating from the ends 48a, 48b.

[0037] The second spacer 40B in this embodiment has been described above. As shown in FIG. 3, in the secondary battery 1 according to this embodiment, a spacer 40 (first spacer 40A) is also arranged on one side X1 of the first direction X (above during the liquid injection). Because the weight of the electrode body 30 is not added to this first spacer 40A, it is not necessary to adopt a structure that takes into account deformation during the liquid injection process. Therefore, a detailed description of the structure of the first spacer 40A will be omitted.

[0038] <Other embodiments> The first embodiment of the technology disclosed herein has been described above. However, the secondary battery disclosed herein is not limited to the first embodiment described above. Specifically, the secondary battery disclosed herein only needs to have a second spacer configured so that the load-bearing capacity of the second wall portion is lower than the load-bearing capacity of the first wall portion, and a rib formed to reinforce the second wall portion. Other configurations are not limited to the first embodiment described above. Below, other embodiments of the technology disclosed herein will be described.

[0039] For example, the passage space 49 of the spacer 40 in the first embodiment is a notch formed in the partition portion 43. However, the spacer need only have a space that allows the internal conductive member (internal terminal or electrode tab) to pass through, and is not limited to the notch-shaped passage space as in the first embodiment. For example, the secondary battery 1A shown in FIG. 7 uses a negative electrode internal terminal 64 having a thin rod-shaped portion 64a extending along the first direction X. If such a configuration is adopted, the passage space 49 may be formed as a small opening through which the rod-shaped portion 64a of the negative electrode internal terminal 64 can be inserted. If such a configuration is adopted, the negative electrode internal terminal 64 and the electrode tab 30t are connected above the second spacer 40B. Note that in the secondary battery 1A configured as shown in FIG. 7, the second wall portion 42 is not divided by the passage space 49. Even in this case, if the second wall portion 42 is lengthened or thickened, the load-bearing capacity of the second wall portion 42 will decrease. As a result, the second wall portion 42 becomes the starting point of deformation even if the second wall portion is not divided by the passage space 49. If the second wall portion 42 is bridged by the rib 45, deformation of the second spacer 40B can be suppressed.

[0040] As shown in FIG. 6, the second spacer 40B in the first embodiment is configured so that the second wall portion 42 is longer than the first wall portion 41. However, as long as the second wall portion 42 can be used as the starting point for deformation, the outer shape of the second spacer is not particularly limited. For example, the second spacer may be a spacer in which the lengths of the first and second wall portions are approximately the same. Even when such a configuration is adopted, if the second wall portion is divided or made thinner, the load-bearing capacity of the second wall portion will decrease. Furthermore, if this second wall portion is bridged with a rib, deformation of the second spacer can be suppressed.

[0041] Furthermore, the second spacer 40B in the first embodiment is configured so that the second wall portion 42 is thinner than the first wall portion 41. However, as long as the second wall portion 42 can be used as the starting point of deformation, the thickness of each wall portion is not particularly limited. For example, the first wall portion and the second wall portion may have approximately the same thickness. Even when such a configuration is adopted, if the second wall portion is divided or lengthened, the load-bearing capacity of the second wall portion will decrease. Furthermore, if this second wall portion is bridged with a rib, deformation of the second spacer can be suppressed.

[0042] Furthermore, the second spacer 40B in the first embodiment has a connecting portion 48 that bridges the first partition portion 43a and the second partition portion 43b. However, the connecting portion is not an essential requirement for the secondary battery disclosed herein. For example, as shown in FIG. 7, if the passage space 49 is a minute opening, the partition portion 43 is not divided, and therefore the connecting portion 48 as shown in FIG. 6 does not need to be formed. Furthermore, the second spacer may not have a connecting portion, and the first partition portion and the second partition portion may be completely separated. If such a configuration is adopted, ribs that support the second wall portion may be formed on each divided spacer. This can suppress deformation of the second wall portion.

[0043] 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.

[0044] The technology disclosed herein includes the following items 1 to 8. The following items 1 to 8 are not limited to the above-described embodiment.

[0045] <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; 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 The pair of sealing plates are a first sealing plate having an injection hole through which the electrolyte is injected into the battery case; a second sealing plate that is placed below in the direction of gravity when the electrolyte is injected; and Equipped with a spacer is disposed in the space between the second sealing plate and the electrode body, the spacer supporting the electrode body from below when the electrolyte is injected; 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; It is equipped with the spacer is configured so that the load-bearing capacity of the second wall portion is lower than the load-bearing capacity of the first wall portion, and is provided with a rib bridging the pair of second wall portions.

[0046] <Item 2> 2. The nonaqueous electrolyte secondary battery according to claim 1, wherein the second wall portion has a thickness smaller than that of the first wall portion.

[0047] <Item 3> 3. The nonaqueous electrolyte secondary battery according to item 1 or 2, wherein the second wall portion has a length longer than the length of the first wall portion.

[0048] <Item 4> 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; a passage space for allowing the internal conductive member to pass through is formed in the spacer; 4. The nonaqueous electrolyte secondary battery according to any one of items 1 to 3, wherein one of the pair of second walls is divided by the passage space.

[0049] <Item 5> 5. The nonaqueous electrolyte secondary battery according to claim 4, wherein the passage space is a notch formed in the partition portion and one of the pair of second wall portions.

[0050] <Item 6> the spacer has a connecting portion that connects the pair of partition portions that face each other across the passage space, 6. The nonaqueous electrolyte secondary battery according to item 4 or 5, wherein the connecting portion extends along the opposing direction of the pair of first side surfaces so as to be adjacent to the second wall portion.

[0051] <Item 7> 7. The nonaqueous electrolyte secondary battery according to any one of items 4 to 6, wherein the rib is provided on each of a pair of the partitions that face each other across the passage space.

[0052] <Item 8> 8. The nonaqueous electrolyte secondary battery according to item 7, wherein the rib extends so as to bridge the pair of second wall portions at a position adjacent to the passage space. [Explanation of symbols]

[0053] 1 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 Second wall 43 Partition 43c aperture 45 Ribs 47 Corner 48 Connection 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; 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 The pair of sealing plates are a first sealing plate having a liquid injection hole through which the electrolyte is injected into the battery case; a second sealing plate that is disposed downward in the direction of gravity when the electrolyte is injected; Equipped with a spacer is disposed in a space between the second sealing plate and the electrode body, the spacer supporting the electrode body from below when the electrolyte is injected; 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; It is equipped with the spacer is configured so that the load-bearing capacity of the second wall portion is lower than the load-bearing capacity of the first wall portion, and is provided with a rib bridging the pair of second wall portions.

2. 2. The nonaqueous electrolyte secondary battery according to claim 1, wherein the second wall portion has a thickness smaller than that of the first wall portion.

3. 2. The nonaqueous electrolyte secondary battery according to claim 1, wherein the second wall portion has a length longer than the length of the first wall portion.

4. 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; a passage space for allowing the internal conductive member to pass through is formed in the spacer; 2. The nonaqueous electrolyte secondary battery according to claim 1, wherein one of the pair of second walls is divided by the passage space.

5. 5. The nonaqueous electrolyte secondary battery according to claim 4, wherein the passage space is a notch formed in the partition portion and one of the pair of second wall portions.

6. the spacer has a connecting portion that connects the pair of partition portions that face each other across the passage space, The nonaqueous electrolyte secondary battery according to claim 4 , wherein the connecting portion extends along the opposing direction of the pair of first side surfaces so as to be adjacent to the second wall portion.

7. 5. The nonaqueous electrolyte secondary battery according to claim 4, wherein the rib is provided on each of a pair of the partitions that face each other across the passage space.

8. 8. The nonaqueous electrolyte secondary battery according to claim 7, wherein the rib extends so as to bridge the pair of second wall portions at a position adjacent to the passage space.

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