Power storage device and method for manufacturing the same

Abstract

To provide a power storage device capable of suppressing occurrence of seal failure even if a crack occurs in a resin member in joining of a seal portion of a case member or a terminal member and the resin member.SOLUTION: A power storage device 1 includes: a case member 30; a terminal member 50; and a resin member 70 for fixing the terminal member 50 to the case member 30. At least one of a case seal portion 31 and a terminal seal portion 51 includes: a plurality of first seal portions 32, 52 that have an annular shape continuous over the entire circumference in circumferential directions IAH and IBH and cause cohesive failure when a bonding with the resin member 70 is broken; and second seal portions 33, 53 that are disposed between the adjacent first seal portions 32, 52, have an annular shape continuous over the entire circumference in the circumferential directions IAH and IBH, and cause interfacial failure when the bonding with the resin member 70 is broken.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to an electricity storage device in which a terminal member is fixed to a case member constituting a case via a resin member, and to a manufacturing method of the electricity storage device. [Background technology]

[0002] As an electric storage device, a battery is known in which positive and negative terminal members are fixed via a resin member to a rectangular plate-like case cover member (case member) constituting a rectangular box-like case. Specifically, the positive and negative terminal members are inserted into insertion holes provided in the case cover member and extend from the inside to the outside of the case. The resin member is airtightly joined to a band-shaped case seal portion surrounding the insertion hole of the case cover member and a band-shaped terminal seal portion located in the vicinity of the insertion hole of the terminal member while insulating them from each other. As a result, the terminal seal portion of the terminal member and the resin member are airtightly sealed in the width direction of the terminal seal portion (hereinafter also referred to as the "sealing direction"), and the case seal portion of the case cover member and the resin member are airtightly sealed in the width direction of the case seal portion (hereinafter also referred to as the "sealing direction"). As a related prior art, for example, Patent Document 1 (see Figs. 2, 6, 7, etc.) can be cited. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2022-079172 Summary of the Invention [Problem to be solved by the invention]

[0004] Conventionally, the terminal seal portion and the resin member of the terminal member are firmly bonded to the resin member over the entire surface of the terminal seal portion so that cohesive failure occurs over the entire surface of the terminal seal portion when the bond between them is broken, and the case seal portion and the resin member of the case member are also firmly bonded to the resin member over the entire surface of the case seal portion so that cohesive failure occurs over the entire surface of the case seal portion when the bond between them is broken. However, in such batteries, it has been found that if a crack (fissure) occurs in the resin member at the joint between the terminal seal portion and the resin member, or at the joint between the case seal portion and the resin member, the crack may then extend in the sealing direction, causing a broken seal (poor sealing).

[0005] The present invention has been made in consideration of the current situation, and provides an electricity storage device that can suppress the occurrence of sealing defects even if cracks occur in the resin member at the joint between the sealing portion of the case member or terminal member and the resin member, and a manufacturing method for the electricity storage device. [Means for solving the problem]

[0006] (1) One aspect of the present invention for solving the above problem is an electricity storage device comprising: a case member having an insertion hole and including a band-shaped case seal portion surrounding the insertion hole; a terminal member inserted into the insertion hole of the case member and including a band-shaped terminal seal portion located in the vicinity of the insertion hole; and a resin member that hermetically joins the case seal portion of the case member and the terminal seal portion of the terminal member while insulating them from each other, and fixes the terminal member to the case member, wherein at least one of the case seal portion and the terminal seal portion has a plurality of first seal portions that are continuous in a circumferential direction of the seal portion and undergo cohesive failure when the bond with the resin member is broken, and second seal portions that are respectively disposed between adjacent first seal portions in a width direction of the seal portion, are continuous in a circumferential direction of the seal portion and undergo interfacial failure when the bond with the resin member is broken.

[0007] In the above-mentioned electricity storage device, at least one of the case seal portion and the terminal seal portion is not firmly joined to the resin member so that cohesive failure occurs over the entire surface of the seal portion (rather than making the entire seal portion into the first seal portion), but rather the seal portion is configured to have a plurality of annular first seal portions that undergo cohesive failure and one or a plurality of annular second seal portions that are disposed between these first seal portions and undergo interfacial failure. This makes it possible to prevent the crack from extending to another first seal portion and causing failure of all the first seal portions included in the seal portions, even if a crack occurs in the resin member at one first seal portion during manufacture or use of the electricity storage device.

[0008] That is, when considering the progression of a crack, if a cohesive failure occurs in the first seal portion and the crack progresses in the sealing direction, the second seal portion adjacent to this first seal portion has a weaker bond with the resin member than the bond between the first seal portion and the resin member, so that interfacial failure easily occurs. However, in the second seal portion, the crack does not continue to progress in the sealing direction, but also progresses in the circumferential direction, so that the stress is relieved by the interfacial failure of the second seal portion. Therefore, the crack is prevented from progressing further in the sealing direction due to the cohesive failure occurring in the next first seal portion. Therefore, in the above-mentioned electricity storage device, even if a crack occurs in the resin member at the joint between the seal portion of the case member or the terminal member and the resin member, the crack progresses in the sealing direction, and all of the first seal portions included in the seal portion are destroyed, and the occurrence of poor sealing can be prevented.

[0009] Examples of the "electricity storage device" include secondary batteries such as lithium ion secondary batteries, sodium ion secondary batteries, and calcium ion secondary batteries, and capacitors such as lithium ion capacitors.

[0010] (2) In the electricity storage device according to (1), the seal portion may include three or more of the first seal portions.

[0011] In the above-mentioned energy storage device, the sealing portion has three or more first sealing portions, which further prevents all of the first sealing portions included in the sealing portion from being destroyed, resulting in poor sealing, compared to when there are two first sealing portions.

[0012] (3) In the energy storage device described in (1) or (2), the multiple first sealing portions may be configured as a forest of nanopillars with a height of 20 nm or more formed by particles derived from a metal constituting the case member or the terminal member being linked together in a string-like manner to form columns, and the spaces between these nanopillars may be filled with a resin material constituting the resin member.

[0013] In the above-mentioned energy storage device, the first sealing portion has a nano-roughened surface at the nano level (nano order) with the above-mentioned nanopillars standing in a row, and resin material is filled between the standing nanopillars, thereby making it possible to achieve particularly good sealing performance between the first sealing portion and the resin member.

[0014] (4) Still another aspect includes a case member having an insertion hole and including a band-shaped case seal portion surrounding the insertion hole, a terminal member inserted into the insertion hole of the case member and including a band-shaped terminal seal portion located in the vicinity of the insertion hole, and a resin member that hermetically bonds the case seal portion of the case member and the terminal seal portion of the terminal member while insulating them from each other, and fixes the terminal member to the case member, wherein at least one of the case seal portion and the terminal seal portion has a ring shape that continues around the entire circumference in the circumferential direction of the seal portion, and agglomerates when the bond with the resin member is broken. A manufacturing method for an electricity storage device having a plurality of first seal portions that will undergo interfacial failure when the bond with the resin member is destroyed, and second seal portions that are arranged between adjacent first seal portions in the width direction of the seal portion, are annular and extend around the entire circumferential direction of the seal portion, and undergo interfacial failure when the bond with the resin member is destroyed, the manufacturing method for an electricity storage device comprising a seal portion forming process for forming the seal portion having a plurality of the first seal portions and the second seal portions in at least one of the case member and the terminal member, and a resin forming process for forming the resin member bonded to the seal portions after the seal portion forming process.

[0015] In the above-described method for manufacturing an electricity storage device, a seal portion having a plurality of first seal portions and second seal portions can be formed in at least one of the case member and the terminal member in the seal portion forming step, and a resin member joined to the seal portion including the first seal portions and the second seal portions can be formed in the resin forming step.

[0016] In addition, in the "resin formation process", examples of methods for forming the resin member include a method of forming (molding) a resin member joined to the case seal portion and the terminal seal portion by insert molding using a case member and a terminal member, and a method of forming a resin member by applying a liquid resin material to the case seal portion and the terminal seal portion and hardening it.

[0017] (5) In the method for manufacturing an electricity storage device described in (4), the first sealing portions are composed of nanopillars having a height of 20 nm or more, which are formed by particles derived from a metal constituting the case member or the terminal member being linked together in a string-like manner to form a columnar shape, and a resin material constituting the resin member is filled between these nanopillars, and the sealing portion forming process may include intermittently irradiating the sealing portion with pulsed laser light while shifting the irradiation position to form the first sealing portions composed of the nanopillars, and the resin forming process may include forming the resin member while filling the spaces between the nanopillars forming the first sealing portions with the resin material.

[0018] In the above-described method for manufacturing an electricity storage device, the first sealing portion having a forest of nanopillars is formed using a pulsed laser beam, so that the first sealing portion having a forest of nanopillars can be easily formed in the sealing portion. In addition, in the resin forming step, the resin member is formed while filling the spaces between the nanopillars standing in the first sealing portion with a resin material, so that a resin member having particularly good sealing properties with the first sealing portion can be formed. [Brief description of the drawings]

[0019] [Figure 1] FIG. 1 is a perspective view of a battery according to an embodiment. [Diagram 2] 1 is a partially cutaway cross-sectional view of a battery according to an embodiment of the present invention taken along the battery height direction and the battery width direction. [Diagram 3] 2 is a partially enlarged cross-sectional view along the battery height direction and battery thickness direction in the vicinity of a case seal portion, a terminal seal portion, and a resin member of a battery according to an embodiment of the present invention. FIG. [Figure 4] 4 is a partially enlarged cross-sectional view of the terminal seal portion in the embodiment, showing a further enlarged vicinity of a plurality of first seal portions and a plurality of second seal portions of the terminal seal portion in the partially enlarged cross-sectional view of FIG. 3. FIG. [Diagram 5] FIG. 4 is a partially enlarged cross-sectional view of the embodiment, showing a further enlarged vicinity of a plurality of first seal portions and a plurality of second seal portions of a case seal portion in the partially enlarged cross-sectional view of FIG. 3. [Figure 6]FIG. 2 is a partially enlarged cross-sectional view showing nano-pillars standing in a forest in a first sealing portion in the embodiment. [Figure 7] 2 is a flowchart of a method for manufacturing a battery according to an embodiment. [Figure 8] 11 is an explanatory diagram showing how a pulsed laser beam is scanned to form a plurality of cup-shaped recesses and nano-pillars standing in the cup-shaped recesses in a seal portion forming step in a manufacturing method for a battery according to an embodiment. FIG. [Figure 9] 1A and 1B are explanatory diagrams of a resin forming process for a battery manufacturing method according to an embodiment, in which (a) shows the state in which positive and negative terminal members are inserted into the insertion holes of the case lid member, and (b) shows the state in which a pair of resin members are molded. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a perspective view of a battery (electricity storage device) 1 according to this embodiment, and FIG. 2 shows a partially cutaway cross-sectional view of the battery 1. FIG. 3 shows a partially enlarged cross-sectional view of the vicinity of the terminal seal portion (seal portion) 51, the case seal portion (seal portion) 31, and the resin member 70 of the battery 1. FIG. 4 shows a partially enlarged cross-sectional view of the vicinity of the first seal portion 52 and the second seal portion 53 of the terminal seal portion 51, and FIG. 5 shows a partially enlarged cross-sectional view of the vicinity of the first seal portion 32 and the second seal portion 33 of the case seal portion 31. In the following description, the battery height direction AH, the battery width direction BH, and the battery thickness direction CH of the battery 1 are defined as the directions shown in FIG. 1 and FIG. 2.

[0021] This battery 1 is a square (rectangular) sealed lithium ion secondary battery that is mounted on vehicles such as hybrid cars, plug-in hybrid cars, and electric cars. The battery 1 is composed of a case 10, an electrode body 40 housed in the case 10, and positive and negative terminal members 50 fixed to the case 10 via resin members 70. The electrode body 40 is covered in a bag-shaped insulating holder 7 made of an insulating film inside the case 10. An electrolyte 5 is also housed inside the case 10, a part of which is impregnated in the electrode body 40 and the remainder is pooled on the bottom wall of the case 10.

[0022] The case 10 is a rectangular box made of metal (aluminum in this embodiment), and is a bottomed square cylinder having a rectangular opening 20c. The case 10 is composed of a case body member 20 that houses the electrode body 40 inside and a rectangular plate-shaped case lid member (case member) 30 that closes the opening 20c of the case body member 20. The opening 20c of the case body member 20 and the peripheral portion 30f of the case lid member 30 are hermetically welded over the entire circumference. The case lid member 30 is provided with a safety valve 11 that breaks and opens when the internal pressure of the case 10 exceeds the valve opening pressure. The case lid member 30 is also provided with a liquid injection hole 30k, which is hermetically sealed with a disk-shaped sealing member 12 made of aluminum.

[0023] The electrode body 40 is a rectangular parallelepiped laminated type, in which a plurality of rectangular positive electrode plates 41 and a plurality of rectangular negative electrode plates 42 are alternately laminated in the battery thickness direction CH with rectangular separators 43 made of a resin porous film interposed therebetween. On one side BH1 of the electrode body 40 in the battery width direction BH, the current collector foils of the positive electrode plates 41 overlap in the battery thickness direction CH to form a positive electrode current collector 40c. This positive electrode current collector 40c is conductively connected to a positive electrode terminal member 50 described later. On the other side BH2 of the electrode body 40 in the battery width direction BH, the current collector foils of the negative electrode plates 42 overlap in the battery thickness direction CH to form a negative electrode current collector 40d. This negative electrode current collector 40d is conductively connected to a negative electrode terminal member 50 described later.

[0024] The case lid member 30 has rectangular insertion holes 30h near the ends of one side BH1 and the other side BH2 in the battery width direction BH, respectively, penetrating the case lid member 30. A positive electrode terminal member 50 made of aluminum is inserted into the insertion hole 30h on the one side BH1, and the terminal member 50 is fixed to the case lid member 30 in a state insulated from the case lid member 30 via a resin member 70. A negative electrode terminal member 50 made of copper is inserted into the insertion hole 30h on the other side BH2, and the terminal member 50 is fixed to the case lid member 30 in a state insulated from the case lid member 30 via the resin member 70.

[0025] The terminal member 50 is formed by pressing metal plates (aluminum plate for the positive electrode, copper plate for the negative electrode). The terminal member 50 is located on the upper side AH1 of the case lid member 30 in the battery height direction AH, and is composed of a rectangular terminal top plate portion 50a extending in the battery width direction BH and the battery thickness direction CH, and a terminal extension portion 50b extending from the terminal top plate portion 50a to the lower side AH2 in the battery height direction AH. The terminal extension portion 50b is bent at an end portion of one side CH1 of the terminal top plate portion 50a in the battery thickness direction CH and extends to the lower side AH2, passes through the insertion hole 30h of the case lid member 30, and further extends through the resin member 70 to the lower side AH2. The terminal extension portion 50b of the positive electrode is welded to the positive electrode current collecting portion 40c of the electrode body 40 at the tip portion of the lower side AH2. Furthermore, the negative electrode terminal extension 50b is welded to the negative electrode current collecting portion 40d of the electrode body 40 at the tip portion of the lower side AH2.

[0026] Of the metal surface 50m of the terminal member 50, a band-shaped portion located near the insertion hole 30h is the terminal seal portion 51 that is joined to the resin member 70 (see Figs. 3 and 4). Specifically, of the surface of the terminal top plate portion 50a, the inner surface and four side surfaces facing the lower side AH2, and of the outer peripheral surface of the terminal extension portion 50b, a portion located inside the resin member 70 on the upper side AH1 are the terminal seal portion 51. This terminal seal portion 51 is composed of a plurality (four in this embodiment) of first seal portions 52 (52A, 52B, 52C, 52D), a plurality (three in this embodiment) of second seal portions 53 (53A, 53B, 53C), and two third seal portions 54 (54A, 54B), which are arranged side by side in the extension direction of the terminal member 50 (the same direction as the battery height direction AH).

[0027] Specifically, each of the first seal portions 52 has a rectangular ring shape extending around the entire circumference in the circumferential direction IBH of the terminal seal portion 51 (in this embodiment, the circumferential direction is along the battery width direction BH and the battery thickness direction CH). The dimension in the width direction of each of the first seal portions 52 is 360 μm or more (approximately 400 μm in this embodiment). As described below, these first seal portions 52 are firmly bonded to the resin member 70, and when the bond between the first seal portion 52 and the resin member 70 is broken, cohesive failure occurs (a crack occurs inside the resin member 70 near the interface between the first seal portion 52 and the resin member 70, breaking the bond).

[0028] Each first seal portion 52 is subjected to a roughening process using a pulsed laser beam LC described later, and is made into a nano-roughened surface at the nano level. That is, in the first seal portion 52, a number of cup-shaped recesses 55 having a diameter Db (see FIG. 8) of 30 to 300 μm (in this embodiment, the diameter Db is approximately 80 μm in the positive electrode terminal member 50, and the diameter Db is approximately 75 μm in the negative electrode terminal member 50) are arranged side by side with some overlapping. In these cup-shaped recesses 55, nano-pillars 56 having a height ha of 20 nm or more (approximately a height ha = 200 nm in this embodiment) are formed by particles 56p derived from the metal constituting the terminal member 50 being linked in a string-like manner to form columns (see FIG. 6). The metal constituting the positive electrode terminal member 50 is aluminum, and the positive electrode nano-pillars 56 are made of particles 56p made of aluminum and aluminum oxide. On the other hand, the metal constituting the negative electrode terminal member 50 is copper, and the negative electrode nanopillars 56 are made of particles 56p made of copper and copper oxide.

[0029] Each of the second seal parts 53 is disposed between the adjacent first seal parts 52 in the width direction (sealing direction) JBH of the terminal seal part 51 (in this embodiment, the same direction as the battery height direction AH). Each of the second seal parts 53 is a rectangular ring shape that is connected to the entire circumference in the circumferential direction IBH of the terminal seal part 51. The dimension of each of the second seal parts 53 in the width direction is 360 μm or more (about 400 μm in this embodiment). As described later, these second seal parts 53 are weakly bonded to the resin member 70, and when the bond between the second seal part 53 and the resin member 70 is broken, an interface break occurs (the second seal part 53 and the resin member 70 are peeled off at the interface between them, and the bond is broken). The above-mentioned bowl-shaped recess 55 and nano-pillar 56 are not formed in the second seal part 53 (the second seal part 53 is not subjected to roughening treatment by the pulsed laser light LC, and is not a nano-roughened surface).

[0030] Of the two third seal parts 54, one third seal part 54A is disposed on the upper side AH1 of the first seal part 52A located on the uppermost side AH1. The other third seal part 54B is disposed on the lower side AH2 of the first seal part 52D located on the lowermost side AH2. The third seal parts 54 are weakly bonded to the resin member 70, similar to the second seal part 53, and when the bond between the third seal part 54 and the resin member 70 is broken, an interface break occurs. The third seal part 54 does not have the above-mentioned bowl-shaped recess 55 and nano-pillar 56.

[0031] Next, the case seal portion 31 of the case lid member 30 will be described (see Figs. 3, 5, and 6). Of the metal surface 30m of the case lid member 30, the band-shaped annular portions surrounding each insertion hole 30h are the case seal portion 31 that are joined to the resin member 70. Specifically, the case seal portion 31 is made up of a rectangular band-shaped outer hole periphery surrounding the insertion hole 30h of the outer main surface facing the upper side AH1 of the case lid member 30, a rectangular band-shaped inner hole periphery surrounding the insertion hole 30h of the inner main surface facing the lower side AH2 of the case lid member 30, and an inner peripheral surface of the insertion hole 30h connecting these portions. This case seal portion 31 consists of a plurality (four in this embodiment) of first seal portions 32 (32A, 32B, 32C, 32D), a plurality (three in this embodiment) of second seal portions 33 (33A, 33B, 33C), and two third seal portions 34 (34A, 34B), which are arranged in the radial direction of the insertion hole 30h (in the direction along the battery width direction BH and the battery thickness direction CH).

[0032] Specifically, each first seal portion 32 has a rectangular ring shape extending around the entire circumference in the circumferential direction IAH of the case seal portion 31 (in this embodiment, the circumferential direction is along the battery width direction BH and the battery thickness direction CH). The width dimension of each first seal portion 32 is 360 μm or more (approximately 400 μm in this embodiment). These first seal portions 32 are firmly bonded to the resin member 70 as described below, and cohesive failure occurs when the bond between the first seal portion 32 and the resin member 70 is broken.

[0033] Each first seal portion 32 is roughened by a pulsed laser beam LC, which will be described later, to form a nano-roughened surface. That is, in the first seal portion 32, a number of cup-shaped recesses 35 having a diameter Db (see FIG. 8) of 30 to 300 μm (approximately the diameter Db=80 μm in this embodiment) are arranged side by side with some overlapping each other. In these cup-shaped recesses 35, nano-pillars 36 are formed by particles 36p derived from the metal constituting the case lid member 30 being linked together in a string to form columns with a height ha of 20 nm or more (approximately the height ha=200 nm in this embodiment) (see FIG. 6). The metal constituting the case lid member 30 is aluminum, and the nano-pillars 36 are made of particles 36p made of aluminum and aluminum oxide.

[0034] Each of the second seal parts 33 is disposed between the adjacent first seal parts 32 in the width direction (sealing direction) JAH of the case seal part 31 (in this embodiment, the radial direction of the insertion hole 30h). Each of the second seal parts 33 is a rectangular ring shape that is connected to the entire circumference in the circumferential direction IAH of the case seal part 31. The dimension of each of the second seal parts 33 in the width direction is 360 μm or more (about 400 μm in this embodiment). As described later, these second seal parts 33 are weakly bonded to the resin member 70, and when the bond between the second seal part 33 and the resin member 70 is broken, an interface break occurs. The above-mentioned bowl-shaped recess 35 and nano-pillar 36 are not formed in the second seal part 33.

[0035] Of the two third seal parts 34, one third seal part 34A is disposed further outward from the first seal part 32A located on the radially outer side (left side in FIG. 5) on the upper side AH1. The other third seal part 34B is disposed further outward from the first seal part 32D located on the radially outer side on the lower side AH2. These third seal parts 34 are weakly bonded to the resin member 70, similar to the second seal part 33, and when the bond between the third seal part 34 and the resin member 70 is broken, an interface break occurs. The third seal part 34 does not have the above-mentioned bowl-shaped recess 35 and nano-pillar 36 formed therein.

[0036] Next, the resin member 70 will be described. The resin member 70 is formed by insert molding using a resin material 75 including a thermoplastic main resin (specifically, polyphenylene sulfide (PPS)), a thermoplastic elastomer, and a filler (specifically, a fibrous glass filler). Each resin member 70 is airtightly joined to the case seal portion 31 of the case lid member 30 and the terminal seal portion 51 of the positive or negative terminal member 50 while insulating them from each other, thereby fixing the terminal member 50 to the case lid member 30.

[0037] The resin member 70 is hermetically joined to the band-shaped terminal seal portion 51 of the terminal member 50 over the entire circumference in the circumferential direction IBH. Specifically, the resin member 70 is hermetically joined to the band-shaped first seal portion 52 (52A to 52D) over the entire circumference with a strong joining force by filling the above-mentioned resin material 75 between the nano-pillars 56 standing in the first seal portion 52 (52A to 52D) of the terminal seal portion 51. The resin member 70 is also hermetically joined to the band-shaped second seal portion 53 (53A to 53C) and the band-shaped third seal portion 54 (54A, 54B) of the terminal seal portion 51 over the entire circumference with a weak joining force. As a result, the gap between the terminal seal portion 51 of the terminal member 50 and the resin member 70 is hermetically sealed in the width direction JBH of the terminal seal portion 51.

[0038] The resin member 70 is airtightly joined to the band-shaped case seal portion 31 of the case lid member 30 over the entire circumference in the circumferential direction IAH. Specifically, the resin member 70 is airtightly joined to the band-shaped first seal portion 32 (32A to 32D) over the entire circumference with a strong joining force by filling the above-mentioned resin material 75 between the nano-pillars 36 standing in the first seal portion 32 (32A to 32D) of the case seal portion 31. The resin member 70 is airtightly joined to the band-shaped second seal portion 33 (33A to 33C) and the band-shaped third seal portion 34 (34A, 34B) of the case seal portion 31 over the entire circumference with a weak joining force. As a result, the gap between the case seal portion 31 of the case lid member 30 and the resin member 70 is airtightly sealed in the width direction JAH of the case seal portion 31.

[0039] In the battery 1 of this embodiment, as described above, the case seal portion 31 and the terminal seal portion 51 are not firmly joined to the resin member 70 so that the entire surface of the seal portion 31, 51 will undergo cohesive failure (the entire seal portion 31, 51 is not the first seal portion 32, 52), but the seal portion 31, 51 has a configuration including a plurality of annular first seal portions 32, 52 that undergo cohesive failure and a plurality of annular second seal portions 33, 53 that undergo interface failure and are disposed between the first seal portions 32, 52. As a result, even if a crack occurs in the resin member 70 at one of the first seal portions 32, 52 during the manufacture or use of the battery 1, it is possible to prevent the crack from extending to another first seal portion 32, 52 and causing the destruction of all the first seal portions 32, 52 included in the seal portion 31, 51.

[0040] That is, in terms of the progression of a crack, when a cohesive failure occurs in a certain first seal portion 32, 52 and the crack progresses in the sealing directions JAH, JBH, in the second seal portion 33, 53 adjacent to this first seal portion 32, 52, the bond with the resin member 70 is weak, so that interfacial failure easily occurs. However, in the second seal portion 33, 53, the crack does not continue to progress in the sealing directions JAH, JBH, but also progresses in the circumferential directions IAH, IBH, so that the stress is relieved by the interfacial failure of the second seal portion 33, 53. Therefore, the occurrence of cohesive failure in the next first seal portion 32, 52 and the further progression of the crack in the sealing directions JAH, JBH are suppressed. Therefore, in the battery 1, even if a crack occurs in the resin member 70 at the joint between the sealing portions 31, 51 of the case lid member 30 and the terminal member 50 and the resin member 70, the crack will not progress in the sealing directions JAH, JBH, and all of the first sealing portions 32, 52 included in the sealing portions 31, 51 will be destroyed, thereby preventing poor sealing.

[0041] Furthermore, in this embodiment, the seal portions 31, 51 of the case cover member 30 and the terminal member 50 each have three or more first seal portions 32, 52, so that the destruction of all of the first seal portions 32, 52 contained in the seal portions 31, 51, which would result in poor sealing, can be further prevented than when there are only two first seal portions 32, 52. In addition, the first sealing portions 32, 52 of the case lid member 30 and the terminal member 50 are nano-roughened surfaces with a forest of nanopillars 36, 56, and resin material 75 is filled between the forest of nanopillars 36, 56, thereby making the sealing property between the first sealing portions 32, 52 and the resin member 70 particularly good.

[0042] Next, a manufacturing method of the battery 1 will be described (see Figs. 7 to 9). First, an unroughened case lid member 30Z is prepared. The unroughened case lid member 30Z is obtained by pressing an aluminum plate. Also, an unroughened terminal member 50Z is prepared. The unroughened terminal member 50Z is obtained by pressing a metal plate (the positive electrode is an aluminum plate, and the negative electrode is a copper plate).

[0043] Then, in the "terminal seal portion forming process (seal portion forming process) S1" (see FIG. 7), the terminal seal portion 51 of the metal surface 50m of the above-mentioned terminal member 50Z is intermittently irradiated with pulsed laser light LC while shifting the irradiation position, to form four band-shaped first seal portions 52 (52A to 52D) in which multiple cup-shaped recesses 55 are arranged while partially overlapping each other (see FIG. 8). Meanwhile, the portions of the terminal seal portion 51 that have not been roughened by the pulsed laser light LC become three band-shaped second seal portions 53 (53A to 53C) and two band-shaped third seal portions 54 (54A, 54B).

[0044] In this embodiment, the irradiation conditions of the positive electrode laser are wavelength 1064 nm, peak power 5 kW, pulse width 150 ns, pitch pb 75 μm, and spot diameter 80 μm. The irradiation conditions of the negative electrode laser are wavelength 1064 nm, peak power 20 kW, pulse width 50 ns, pitch pb 60 μm, and spot diameter 75 μm.

[0045] In the terminal seal portion 51, in the area having a circular shape in a plan view irradiated with the pulsed laser light LC, the metals (aluminum for the positive electrode, copper for the negative electrode) near the surface melt and turn into steam. When the temperature of the steam drops thereafter, it turns into particles 56p (particles 56p of aluminum and aluminum oxide for the positive electrode, and particles 56p of copper and copper oxide for the negative electrode) and accumulates in the bowl-shaped recess 55. By intermittently irradiating the terminal seal portion 51 with the pulsed laser light LC while shifting the irradiation position, the particles 56p accumulate in a string of beads and combine to form columns, forming a forest of nano-columns 56 (see FIGS. 8 and 6).

[0046] Separately, in the "case seal forming process (seal forming process) S2" (see FIG. 7), the case seal 31 of the metal surface 30m of the case lid member 30Z is intermittently irradiated with the pulsed laser light LC while shifting the irradiation position, to form four annular first seal parts 32 (32A to 32D) each having a number of overlapping cup-shaped recesses 35 (see FIG. 8). In each cup-shaped recess 35, nano-pillars 56 are formed by aluminum and aluminum oxide particles 36p accumulating and bonding in a string-like manner to form columns (see FIG. 6). Meanwhile, the portions of the case seal part 31 that have not been subjected to the nano-level roughening treatment by the pulsed laser light LC become three annular second seal parts 33 (33A to 33C) and two annular third seal parts 34 (34A, 34B). The laser irradiation conditions were the same as those used when the positive electrode terminal member 50 was irradiated with a laser in the terminal seal portion forming step S1.

[0047] Next, in the "resin formation process S3" (see FIG. 7), resin members 70 are formed which are joined to the seal portions 31, 51 of the case lid member 30 and the terminal members 50. In this embodiment, with the positive and negative terminal members 50 respectively inserted into the insertion holes 30h of the case lid member 30, the pair of resin members 70 are insert-molded using the above-mentioned resin material 75 (see FIG. 9). Specifically, the resin forming step S3 is performed using a molding die (not shown) having an upper die and a lower die. First, the case lid member 30 is placed at a predetermined position in the lower die, and the positive and negative terminal members 50 are inserted into the pair of insertion holes 30h of the case lid member 30 (see FIG. 9(a)). After that, the upper die is moved toward the lower die to close the molding die. Next, molten resin material 75 is injected into each of the two cavities of the molding die. At that time, the resin material 75 is also filled between the nano pillars 36 standing in a forest in the first seal portion 32 of the case lid member 30 and between the nano pillars 56 standing in a forest in the first seal portion 52 of the terminal member 50.

[0048] Then, the resin members 70 are formed to hermetically join the case seal portion 31 of the case lid member 30, i.e., the first seal portion 32 (32A to 32D), the second seal portion 33 (33A to 33C), and the third seal portion 34 (34A, 34B) all around in the circumferential direction IAH, and to hermetically join the terminal seal portion 51 of the terminal member 50, i.e., the first seal portion 52 (52A to 52D), the second seal portion 53 (53A to 53C), and the third seal portion 54 (54A, 54B) all around in the circumferential direction IBH (see FIG. 9(b)). Thereafter, the lid assembly 15 in which the positive and negative terminal members 50 are fixed to the case lid member 30 via the resin members 70 is removed from the molding die.

[0049] The first seal parts 32, 52 of the seal parts 31, 51 have a nano-roughened surface, and resin material 75 is filled between the forest of nano-pillars 36, 56, so that they are firmly bonded to the resin member 70. As a result, when the bond between the first seal parts 32, 52 and the resin member 70 is broken, it is a cohesive failure. On the other hand, the second seal parts 33, 53 and the third seal parts 34, 54 of the seal parts 31, 51 do not have a nano-roughened surface, and the bond with the resin member 70 is weak, so when the bond with the resin member 70 is broken, it is an interfacial failure.

[0050] Next, in the "electrode body connecting step S4" (see FIG. 7), an electrode body 40 is prepared by stacking a positive electrode plate 41, a negative electrode plate 42, and a separator 43, and the terminal extension portion 50b of the positive electrode terminal member 50 of the lid assembly 15 described above is welded to the positive electrode current collecting portion 40c of the electrode body 40 (see FIGS. 2 and 1). Also, the terminal extension portion 50b of the negative electrode terminal member 50 of the lid assembly 15 is welded to the negative electrode current collecting portion 40d of the electrode body 40. Thereafter, the electrode body 40 is wrapped in a bag-shaped insulating holder 7.

[0051] Next, in the "electrode assembly accommodating / case forming process S5", a case body member 20 is prepared, the electrode assembly 40 covered with the insulating holder 7 described above is inserted into the case body member 20, and the opening 20c of the case body member 20 is closed with the case lid member 30. Then, the opening 20c of the case body member 20 and the peripheral portion 30f of the case lid member 30 are laser-welded airtightly all around to form the case 10 accommodating the electrode assembly 40 therein.

[0052] Next, in a "pouring and sealing step S6", electrolyte 5 is poured into case 10 through pouring hole 30k, and electrolyte 5 is impregnated into electrode body 40. Thereafter, pouring hole 30k is covered from the outside with sealing member 12, and sealing member 12 is laser-welded to case 10 airtightly. Next, in the "initial charging and aging step S7", a charging device (not shown) is connected to the battery 1 to perform an initial charge on the battery 1. After that, the initially charged battery 1 is left to stand for a predetermined time to age the battery 1. In this way, the battery 1 is completed.

[0053] In the manufacturing method of the battery 1 of this embodiment, in the seal portion forming steps S1, S2, the seal portion 31, 51 having a plurality of first seal portions 32, 52 and a plurality of second seal portions 33, 53 can be formed in the case lid member 30 and the terminal member 50. In addition, in the resin forming step S3, a resin member 70 joined to the seal portion 31, 51 including the first seal portions 32, 52 and the second seal portions 33, 53 can be formed.

[0054] Furthermore, in this embodiment, the first seal portions 32, 52 including the forest of nanopillars 36, 56 are formed using the pulsed laser beam LC, so that the first seal portions 32, 52 including the forest of nanopillars 36, 56 can be easily formed in the seal portions 31, 51. Furthermore, in the resin formation step S3, the resin member 70 is formed while filling the spaces between the nanopillars 36, 56 that forest of the first seal portions 32, 52 with the resin material 75, so that the resin member 70 having particularly good sealing properties with the first seal portions 32, 52 can be formed.

[0055] Although the present invention has been described above with reference to an embodiment, it goes without saying that the present invention is not limited to the embodiment and can be modified as appropriate without departing from the spirit of the present invention. For example, in the embodiment, the first seal portion 32, 52 of the seal portion 31, 51 is a nano-roughened surface with nano-pillars 36, 56 standing in a row, and the first seal portion 32, 52 and the resin member 70 are firmly bonded to each other so as to cause cohesive failure, but this is not limited to the above. Other roughening treatments, for example, physical roughening treatments such as shot blasting, polishing, and thermal spraying, or chemical roughening treatments such as anodizing, can be used to make the first seal portion 32, 52 a roughened surface, and the first seal portion 32, 52 and the resin member 70 can be firmly bonded to each other so as to cause cohesive failure. [Explanation of symbols]

[0056] 1. Battery (energy storage device) 10 Cases 30 Case cover member (case member) 30h Through hole 31 (case lid member) case seal portion (seal portion) 32, 32A, 32B, 32C, 32D (Case seal part) First seal part 33, 33A, 33B, 33C (Case seal part) Second seal part 34, 34A, 34B (Case seal part) 3rd seal part 36 Nano pillars (of case cover material) 36p (derived from the metal that makes up the case cover) particles 40 Electrode body 50 Terminal parts (metal parts) 51 (Terminal member) terminal seal part (seal part) 52, 52A, 52B, 52C, 52D (Terminal seal part) First seal part 53, 53A, 53B, 53C (terminal seal part) second seal part 54, 54A, 54B (Terminal seal part) 3rd seal part 56 Nano pillars (of terminal parts) 56p particles (derived from the metal that constitutes the terminal material) 70 Resin parts 75 Resin material IAH (Case seal) Circumferential direction IBH (Terminal seal part) Circumferential direction JAH (Case seal part) width direction (seal direction) JBH (Terminal seal part) Width direction (seal direction) ha (height of nano pillar) LC Pulsed Laser Light S1 Terminal seal forming process (seal forming process) S2 Case seal forming process (seal forming process) S3 Resin forming process

Claims

1. a case member having an insertion hole and including a band-shaped case seal portion surrounding the insertion hole; a terminal member that is inserted into the insertion hole of the case member and includes a terminal seal portion that is an annular band and is located in the vicinity of the insertion hole; a resin member that hermetically bonds the case seal portion of the case member and the terminal seal portion of the terminal member while insulating them from each other, and fixes the terminal member to the case member. An electricity storage device, At least one of the case seal and the terminal seal is a plurality of first seal portions that are annularly connected around the entire circumference of the seal portion and that undergo cohesive failure when the bond with the resin member is broken; and a second seal portion that is disposed between the first seal portions adjacent to each other in the width direction of the seal portion, is annular and continues around the entire circumference of the seal portion in the circumferential direction, and causes an interfacial failure when the bond with the resin member is broken. Energy storage device.

2. The power storage device according to claim 1 , The seal portion includes three or more first seal portions. Energy storage device.

3. The electricity storage device according to claim 1 or 2, The plurality of first seal portions include The case member or the terminal member is made of metal-derived particles that are linked together in a string to form nano-pillars with a height of 20 nm or more. The spaces between the nano-pillars are filled with the resin material that constitutes the resin member. Energy storage device.

4. a case member having an insertion hole and including a band-shaped case seal portion surrounding the insertion hole; a terminal member that is inserted into the insertion hole of the case member and includes a terminal seal portion that is an annular band and is located in the vicinity of the insertion hole; a resin member that hermetically bonds the case seal portion of the case member and the terminal seal portion of the terminal member while insulating them from each other, and fixes the terminal member to the case member, At least one of the case seal and the terminal seal is a plurality of first seal portions that are annularly connected around the entire circumference of the seal portion and that undergo cohesive failure when the bond with the resin member is broken; and a second seal portion that is disposed between the first seal portions adjacent to each other in the width direction of the seal portion, is annular and continues around the entire circumference of the seal portion in the circumferential direction, and causes an interfacial failure when the bond with the resin member is broken. A method for manufacturing an electricity storage device, comprising: a seal portion forming step of forming the seal portion having a plurality of the first seal portions and the second seal portions in at least one of the case member and the terminal member; and forming a resin member bonded to the seal portion after the seal portion forming step. A method for manufacturing an electricity storage device.

5. A method for producing the electricity storage device according to claim 4, comprising the steps of: The plurality of first seal portions include nanopillars having a height of 20 nm or more formed by linking together particles derived from a metal constituting the case member or the terminal member in a string-like manner stand in a forest, and a resin material constituting the resin member is filled between these nanopillars; The seal portion forming step includes: A pulsed laser beam is intermittently irradiated onto the seal portion while shifting an irradiation position thereof to form a plurality of the first seal portions each including the nano-columns; The resin forming step includes: The resin member is formed while filling the gaps between the nano-columns standing in the first seal portion with the resin material. A method for manufacturing an electricity storage device.

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