Electricity 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 terminal members are fixed to case members constituting a case via a resin member, and to a method for manufacturing the electricity storage device. [Background technology]

[0002] A known energy storage device is a battery in which positive and negative terminal members are fixed via a resin member to a rectangular plate-shaped case cover member (case member) that forms a rectangular box-shaped 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 bonded to a band-shaped annular case seal portion of the case cover member that surrounds the insertion hole and a band-shaped annular terminal seal portion of the terminal member that is located near the insertion hole while insulating them from each other. This provides an airtight seal between the terminal seal portion of the terminal member and the resin member in the width direction of the terminal seal portion (hereinafter also referred to as the "sealing direction"), and also provides an airtight seal between the case seal portion of the case cover member and the resin member in the width direction of the case seal portion (hereinafter also referred to as the "sealing direction"). Related prior art includes, for example, Patent Document 1 (see FIGS. 2, 6, 7, etc.). [Prior art documents] [Patent documents]

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

[0004] Conventionally, the terminal seal portion and 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 breaks.Furthermore, the case seal portion and 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 breaks. 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 between the case seal portion and the resin member, the crack may then extend in the sealing direction, resulting in 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 prevent poor sealing 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 method for manufacturing this electricity storage device. [Means for solving the problem]

[0006] (1) One aspect of the present invention for solving the above problem is an electric storage device including: a case member having an insertion hole and including a band-shaped annular case seal portion surrounding the insertion hole; a terminal member inserted into the insertion hole of the case member and including a band-shaped annular 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 an annular shape that continues around the entire periphery in the circumferential direction of the seal portion, and when the bond with the resin member is broken, a cohesive failure occurs. 3 or more and a second seal portion arranged between adjacent first seal portions in the width direction of the seal portion, having an annular shape extending around the entire circumferential direction of the seal portion, and which undergoes interfacial failure when the bond with the resin member is broken.

[0007] In the above-described electricity storage device, at least one of the case seal and the terminal seal is not firmly joined to the resin member so that cohesive failure occurs across the entire surface of the seal (rather than the entire seal being the first seal), but rather the seal is configured to have a plurality of annular first seals that undergo cohesive failure and one or more annular second seals that are disposed between these first seals and undergo interfacial failure. This prevents the crack from spreading to other first seals and causing failure of all of the first seals included in the seals, even if a crack occurs in the resin member at one first seal during manufacture or use of the electricity storage device. Furthermore, in the above-mentioned energy storage device, the sealing portion has three or more first sealing portions, which further reduces the risk of all of the first sealing portions included in the sealing portion being destroyed and causing poor sealing compared to when there are two first sealing portions.

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

[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.

[0012] ( 2 )(1 ) The electricity storage device described above, 3 or moreThe first sealing portion of the electricity storage device may be a forest of nanopillars with a height of 20 nm or more, which are formed by particles derived from the metal that constitutes the case member or the terminal member being linked together in a string-like manner to form pillars, and the spaces between these nanopillars are filled with resin material that constitutes the resin member.

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

[0014] ( 3 In still another aspect, the terminal member includes a case member having an insertion hole and including a band-shaped annular case seal portion surrounding the insertion hole; a terminal member inserted into the insertion hole of the case member and including a band-shaped annular 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 an annular shape that continues around the entire periphery in the circumferential direction of the seal portion, and when the bond with the resin member is broken, a cohesive failure occurs. 3 or more and annular second seal portions arranged between adjacent first seal portions in a width direction of the seal portion, continuing along the entire circumferential direction of the seal portion, and causing an interfacial failure when the bond with the resin member is broken, wherein at least one of the case member and the terminal member has: 3 or more and a resin forming process for forming the resin member joined to the seal portion after the seal portion forming process.

[0015] In the method for manufacturing the electricity storage device described above, in the seal portion forming step, at least one of the case member and the terminal member is 3 or moreA seal portion having the first seal portion and the second seal portion can be formed. In the resin forming step, a resin member joined to the seal portion including the first seal portion and the second seal portion can be formed.

[0016] In addition, in the "resin forming process," methods for forming the resin member include, for example, a method of forming (molding) a resin member joined to the case seal portion and the terminal seal portion by insert molding using the case member and the 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] ( 4 )( 3 A method for producing the electricity storage device according to 3 or more The first seal portion is made up of nanopillars with a height of 20 nm or more, each of which is formed by particles derived from the metal constituting the case member or the terminal member being linked together in a string-like pattern, and the spaces between these nanopillars are filled with a resin material constituting the resin member. The seal portion forming step is performed by intermittently irradiating the seal portion with pulsed laser light while shifting the irradiation position, thereby forming a forest of nanopillars. 3 or more The first seal portion is formed, and the resin forming step includes: 3 or more The method for manufacturing an electricity storage device may include forming the resin member while filling the spaces between the nano-pillars standing in the first sealing portion with the resin material.

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

[0019] [Figure 1] FIG. 1 is a perspective view of a battery according to an embodiment. [Figure 2] 1 is a partially cutaway cross-sectional view of a battery according to an embodiment, taken along the battery height direction and the battery width direction. [Figure 3] 3 is a partially enlarged cross-sectional view of the battery according to the embodiment, taken along the battery height direction and battery thickness direction, in the vicinity of the case seal portion, the terminal seal portion, and the resin member. FIG. [Figure 4] 4 is a partially enlarged cross-sectional view of the embodiment, showing a further enlarged view of the 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. [Figure 5] 4 is a partially enlarged cross-sectional view of the embodiment, showing a further enlarged view of the vicinity of a plurality of first seal portions and a plurality of second seal portions of the case seal portion in the partially enlarged cross-sectional view of FIG. 3. FIG. [Figure 6] FIG. 2 is a partially enlarged cross-sectional view showing nano-pillars standing in a forest in the first sealing portion in the embodiment. [Figure 7] 3 is a flowchart of a method for manufacturing a battery according to an embodiment. [Figure 8] 10A and 10B are explanatory views showing how a plurality of bowl-shaped recesses and nano-pillars standing in the bowl-shaped recesses are formed by scanning with pulsed laser light in a sealing portion forming step in the manufacturing method of the battery according to the embodiment. [Figure 9] 10A and 10B are explanatory diagrams of the resin forming process in the manufacturing method of the battery according to the embodiment, where FIG. 10A shows the state in which the positive and negative terminal members are inserted into the insertion holes of the case lid member, and FIG. 10B shows the state in which the pair of resin members are molded. DETAILED DESCRIPTION OF THE INVENTION

[0020] An embodiment of the present invention will be described below with reference to the drawings. Fig. 1 shows a perspective view of a battery (energy 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 battery 1, including the terminal seal portion (seal portion) 51, the case seal portion (seal portion) 31, and the resin member 70. Fig. 4 shows a partially enlarged cross-sectional view 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 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 Figs. 1 and 2.

[0021] This battery 1 is a rectangular (rectangular) sealed lithium ion secondary battery that is installed in vehicles such as hybrid cars, plug-in hybrid cars, and electric cars. The battery 1 is composed of a case 10, an electrode assembly 40 housed in the case 10, and positive and negative terminal members 50 fixed to the case 10 via resin members 70. The electrode assembly 40 is covered in a bag-shaped insulating holder 7 made of insulating film within the case 10. The case 10 also contains an electrolyte 5, a portion of which is impregnated into the electrode assembly 40 and the remainder of which 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 configured from a case body member 20 in the shape of a bottomed square cylinder with a rectangular opening 20c, which houses the electrode assembly 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 edge 30f of the case lid member 30 are hermetically welded all around. The case lid member 30 is provided with a safety valve 11 that ruptures and opens when the internal pressure of the case 10 exceeds a valve opening pressure. The case lid member 30 is also provided with a liquid inlet 30k, which is hermetically sealed with a disk-shaped sealing member 12 made of aluminum.

[0023] The electrode assembly 40 is a rectangular parallelepiped laminate, and is formed by alternately stacking multiple rectangular positive electrode plates 41 and multiple rectangular negative electrode plates 42 in the battery thickness direction CH, with rectangular separators 43 made of porous resin films sandwiched between them. On one side BH1 of the electrode assembly 40 in the battery width direction BH, the current collecting foils of the positive electrode plates 41 overlap in the battery thickness direction CH to form a positive electrode current collecting portion 40c. This positive electrode current collecting portion 40c is electrically connected to a positive electrode terminal member 50, which will be described later. On the other side BH2 of the electrode assembly 40 in the battery width direction BH, the current collecting foils of the negative electrode plates 42 overlap in the battery thickness direction CH to form a negative electrode current collecting portion 40d. This negative electrode current collecting portion 40d is electrically connected to a negative electrode terminal member 50, which will be described later.

[0024] Rectangular insertion holes 30h penetrating the case lid member 30 are provided near the ends of one side BH1 and the other side BH2 in the battery width direction BH. 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 while being 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 while being 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 and 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 consists 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 a lower side AH2 in the battery height direction AH. The terminal extension portion 50b bends at an end of one side CH1 in the battery thickness direction CH of the terminal top plate portion 50a and extends to the lower side AH2, passes through the insertion hole 30h of the case lid member 30, and further penetrates the resin member 70 to extend to the lower side AH2. The positive electrode terminal extension portion 50b is welded to the positive electrode current collecting portion 40c of the electrode body 40 at the tip of the lower side AH2. The negative electrode terminal extension 50b is welded to the negative electrode current collecting portion 40d of the electrode body 40 at the tip end 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 bonded 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 the portion of the outer peripheral surface of the terminal extension portion 50b that is located inside the resin member 70 on the upper side AH1 are the terminal seal portion 51. This terminal seal portion 51 is made up 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 first seal portion 52 has a rectangular ring shape that extends around the entire periphery of the terminal seal portion 51 in the circumferential direction IBH (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 52 is 360 μm or more (approximately 400 μm in this embodiment). As will be described later, these first seal portions 52 are firmly bonded to the resin member 70, and cohesive failure occurs when the bond between the first seal portion 52 and the resin member 70 is broken (a crack occurs inside the resin member 70 near the interface between the first seal portion 52 and the resin member 70, causing the bond to break).

[0028] Each first seal portion 52 is subjected to a roughening treatment using pulsed laser light LC (described later) to form a nano-roughened surface at the nano level. Specifically, the first seal portion 52 has a number of cup-shaped recesses 55, each with a diameter Db (see FIG. 8 ) of 30 to 300 μm (in this embodiment, the diameter Db of the positive electrode terminal member 50 is approximately 80 μm, and the diameter Db of the negative electrode terminal member 50 is approximately 75 μm), arranged in a partially overlapping arrangement. These cup-shaped recesses 55 are filled with nanopillars 56 (see FIG. 6 ), each of which is made up of particles 56p derived from the metal constituting the terminal member 50, linked together in a string to form a columnar shape with a height ha of 20 nm or more (in this embodiment, the height ha is approximately 200 nm). The metal constituting the positive electrode terminal member 50 is aluminum, and the positive electrode nanopillars 56 are made of particles 56p of aluminum and aluminum oxide. On the other hand, the metal forming the terminal member 50 of the negative electrode is copper, and the nanopillars 56 of the negative electrode are made of particles 56p made of copper and copper oxide.

[0029] Each second seal portion 53 is disposed between adjacent first seal portions 52 in the width direction (sealing direction) JBH of the terminal seal portion 51 (in this embodiment, the same direction as the battery height direction AH). Each second seal portion 53 has a rectangular ring shape that extends around the entire periphery of the terminal seal portion 51 in the circumferential direction IBH. The width dimension of each second seal portion 53 is 360 μm or more (approximately 400 μm in this embodiment). As described below, these second seal portions 53 are weakly bonded to the resin member 70, and when the bond between the second seal portion 53 and the resin member 70 is broken, an interfacial failure occurs (the second seal portion 53 and the resin member 70 peel off at the interface between them, breaking the bond). The second seal portion 53 does not have the aforementioned bowl-shaped recesses 55 or nano-pillars 56 (the second seal portion 53 is not roughened by pulsed laser light LC and does not have a nano-roughened surface).

[0030] Of the two third seal portions 54, the third seal portion 54A is located above the first seal portion 52A, which is located on the uppermost side AH1. The other third seal portion 54B is located below the first seal portion 52D, which is located on the lowermost side AH2. Similar to the second seal portion 53, these third seal portions 54 have weak bonds with the resin member 70, and when the bond between the third seal portion 54 and the resin member 70 breaks, it results in interfacial failure. The third seal portion 54 does not have the bowl-shaped recesses 55 or nanopillars 56 described above.

[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 portions 31 that are bonded to the resin member 70. Specifically, the case seal portion 31 includes a rectangular band-shaped outer hole periphery surrounding the insertion hole 30h on 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 on the inner main surface facing the lower side AH2 of the case lid member 30, and the inner peripheral surface of the insertion hole 30h that connects these. This case seal portion 31 consists of multiple (four in this embodiment) first seal portions 32 (32A, 32B, 32C, 32D), multiple (three in this embodiment) 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 that extends around the entire periphery 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). As will be described later, these first seal portions 32 are firmly bonded to the resin member 70, 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 subjected to a roughening treatment using pulsed laser light LC (described later) to form a nano-roughened surface. Specifically, the first seal portion 32 has a number of cup-shaped recesses 35, each with a diameter Db (see FIG. 8) of 30 to 300 μm (approximately 80 μm in this embodiment), arranged in a line with some overlapping. These cup-shaped recesses 35 are filled with nanopillars 36 (see FIG. 6), each of which is made up of particles 36p derived from the metal constituting the case lid member 30, linked together in a string to form columns with a height ha of 20 nm or more (approximately 200 nm in this embodiment). The metal constituting the case lid member 30 is aluminum, and the nanopillars 36 are made up of particles 36p of aluminum and aluminum oxide.

[0034] Each second seal portion 33 is disposed between adjacent first seal portions 32 in the width direction (sealing direction) JAH of the case seal portion 31 (in this embodiment, the radial direction of the insertion hole 30h). Each second seal portion 33 has a rectangular ring shape that extends around the entire circumference of the case seal portion 31 in the circumferential direction IAH. The width dimension of each second seal portion 33 is 360 μm or more (approximately 400 μm in this embodiment). As will be described later, these second seal portions 33 are weakly bonded to the resin member 70, and when the bond between the second seal portion 33 and the resin member 70 breaks, an interfacial failure occurs. The second seal portion 33 does not have the bowl-shaped recesses 35 and nanopillars 36 described above.

[0035] Of the two third seal portions 34, the third seal portion 34A is located further outward from the first seal portion 32A, which is located radially outward (leftward in FIG. 5) on the upper side AH1. The other third seal portion 34B is located further outward from the first seal portion 32D, which is located radially outward on the lower side AH2. Similar to the second seal portion 33, these third seal portions 34 have weak bonds with the resin member 70, and when the bond between the third seal portion 34 and the resin member 70 breaks, it results in interfacial failure. The third seal portion 34 does not have the bowl-shaped recesses 35 or nanopillars 36 described above.

[0036] Next, the resin member 70 will be described. The resin member 70 is insert-molded using a resin material 75 containing 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 bonded 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 airtightly bonded to the band-annular terminal seal portion 51 of the terminal member 50 over the entire periphery in the circumferential direction IBH. Specifically, the resin member 70 is airtightly bonded to the band-annular first seal portion 52 (52A to 52D) over the entire periphery with strong bonding force by filling the spaces between the nano-pillars 56 that stand in each of the first seal portions 52 (52A to 52D) of the terminal seal portion 51 with the above-mentioned resin material 75. The resin member 70 is also airtightly bonded to the band-annular second seal portion 53 (53A to 53C) and the band-annular third seal portion 54 (54A, 54B) of the terminal seal portion 51 over the entire periphery with weak bonding force. This provides an airtight seal between the terminal seal portion 51 of the terminal member 50 and the resin member 70 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 strong joining force by filling the spaces between the nano-columns 36 that stand in each of the first seal portions 32 (32A to 32D) of the case seal portion 31 with the above-mentioned resin material 75. 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 weak joining force. This provides an airtight seal between the case seal portion 31 of the case lid member 30 and the resin member 70 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 31 and the terminal seal 51 are not firmly joined to the resin member 70 so that the entire surfaces of these seals 31, 51 undergo cohesive failure (rather than the entire seals 31, 51 being the first seals 32, 52). Instead, the seals 31, 51 are configured to have a plurality of annular first seals 32, 52 that undergo cohesive failure and a plurality of annular second seals 33, 53 that are disposed between these first seals 32, 52 and undergo interfacial failure. This prevents a crack from spreading to other first seals 32, 52 and causing failure of all of the first seals 32, 52 included in the seals 31, 51, even if a crack occurs in the resin member 70 at one first seal 32, 52 during manufacture or use of the battery 1.

[0040] That is, when considering the progression of a crack, if cohesive failure occurs in a certain first seal portion 32, 52 and the crack progresses in the sealing directions JAH, JBH, interfacial failure easily occurs in the second seal portion 33, 53 adjacent to this first seal portion 32, 52 because the bond with the resin member 70 is weak. 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, and therefore the stress is relieved by the interfacial failure of the second seal portion 33, 53. As a result, cohesive failure in the next first seal portion 32, 52 and the crack are prevented from further progressing in the sealing directions JAH, JBH. 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 progress in the sealing directions JAH, JBH, destroying all of the first sealing portions 32, 52 included in the sealing portions 31, 51, 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 it is possible to further prevent all of the first seal portions 32, 52 included in the seal portion 31, 51 from being destroyed, resulting in poor sealing, compared to when there are 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 have nano-roughened surfaces with a forest of nano-pillars 36, 56, and resin material 75 is filled between the forest of nano-pillars 36, 56, thereby making the sealing between the first sealing portions 32, 52 and the resin member 70 particularly good.

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

[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 with some overlapping (see FIG. 8). Meanwhile, the portions of the terminal seal portion 51 that have not been roughened with 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 were set to a wavelength of 1064 nm, a peak output of 5 kW, a pulse width of 150 ns, a pitch pb of 75 μm, and a spot diameter of 80 μm. The irradiation conditions of the negative electrode laser were set to a wavelength of 1064 nm, a peak output of 20 kW, a pulse width of 50 ns, a pitch pb of 60 μm, and a spot diameter of 75 μm.

[0045] In the area of ​​the terminal seal portion 51 that is circular in plan view and irradiated with the pulsed laser beam LC, the metals (aluminum for the positive electrode and copper for the negative electrode) that form near the surface melt and then vaporize. Then, as the temperature of the vapor decreases, the vapor becomes particles 56p (aluminum and aluminum oxide particles 56p for the positive electrode, and copper and copper oxide particles 56p for the negative electrode) and accumulates in the bowl-shaped recess 55. By intermittently irradiating the terminal seal portion 51 with the pulsed laser beam LC while shifting the irradiation position, the particles 56p accumulate in a string of beads and combine to form columns, forming a forest of nanocolumns 56 (see FIGS. 8 and 6).

[0046] Separately, in the "case seal portion forming process (seal portion forming process) S2" (see FIG. 7), pulsed laser light LC is intermittently irradiated onto the case seal portion 31 of the metal surface 30m of the case lid member 30Z described above while shifting the irradiation position, thereby forming four annular first seal portions 32 (32A to 32D) each having a plurality of overlapping cup-shaped recesses 35 (see FIG. 8). Each cup-shaped recess 35 is filled with nano-pillars 56 formed by the accumulation and bonding of aluminum and aluminum oxide particles 36p in a string-like pattern (see FIG. 6). Meanwhile, portions of the case seal portion 31 that have not been subjected to nano-level roughening treatment with pulsed laser light LC become three annular second seal portions 33 (33A to 33C) and two annular third seal portions 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 forming process S3" (see FIG. 7), resin members 70 are formed that are bonded 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 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 then 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 this time, the resin material 75 is also filled between the nanopillars 36 standing in the first seal portion 32 of the case lid member 30 and between the nanopillars 56 standing in the first seal portion 52 of the terminal member 50.

[0048] Then, resin members 70 are formed that are airtightly joined to the case seal portions 31 of the case lid member 30, i.e., the first seal portions 32 (32A to 32D), the second seal portions 33 (33A to 33C), and the third seal portions 34 (34A, 34B), over the entire circumference in the circumferential direction IAH, and to the terminal seal portions 51 of the terminal members 50, i.e., the first seal portions 52 (52A to 52D), the second seal portions 53 (53A to 53C), and the third seal portions 54 (54A, 54B), over the entire circumference 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] Of the seal parts 31, 51, the first seal parts 32, 52 have a nano-roughened surface, and resin material 75 is filled between the standing nano-pillars 36, 56, so 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 breaks, it is a cohesive failure. On the other hand, of the seal parts 31, 51, the second seal parts 33, 53 and the third seal parts 34, 54 do not have a nano-roughened surface, and therefore the bond with the resin member 70 is weak, so when the bond with the resin member 70 breaks, 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 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. The opening 20c of the case body member 20 and the peripheral edge portion 30f of the case lid member 30 are then laser-welded airtightly around the entire periphery to form the case 10 accommodating the electrode assembly 40 inside.

[0052] Next, in the "pouring and sealing step S6," the electrolyte 5 is poured into the case 10 through the pouring hole 30k, and the electrolyte 5 is impregnated into the electrode body 40. Thereafter, the pouring hole 30k is covered from the outside with a sealing member 12, and the sealing member 12 is laser-welded to the case 10 in an airtight manner. Next, in the "initial charging and aging step S7," a charging device (not shown) is connected to the battery 1, and the battery 1 is initially charged. 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 and S2, seal portions 31 and 51 having a plurality of first seal portions 32 and 52 and a plurality of second seal portions 33 and 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 can be formed that is joined to the seal portions 31 and 51 including the first seal portions 32 and 52 and the second seal portions 33 and 53.

[0054] Furthermore, in this embodiment, the first seal portions 32, 52 each including a forest of nanopillars 36, 56 are formed using pulsed laser light LC, and therefore the first seal portions 32, 52 each including a 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 each including a forest of nanopillars 36, 56 in the first seal portions 32, 52 with resin material 75, and therefore the resin member 70 has particularly good sealing properties with the first seal portions 32, 52.

[0055] Although the present invention has been described above in accordance with the embodiments, it goes without saying that the present invention is not limited to the embodiments and can be modified and applied as appropriate within the scope of the invention. For example, in the embodiment, the first seal portion 32, 52 of the seal portion 31, 51 has a nano-roughened surface with a forest of nano-pillars 36, 56, and the first seal portion 32, 52 and the resin member 70 are firmly bonded together so as to cause cohesive failure, but this is not limited to this. Other roughening treatments, for example, physical roughening treatments such as shot blasting, polishing, and thermal spraying, or chemical roughening treatments such as anodizing, can also be used to form the first seal portion 32, 52 into a roughened surface, and to firmly bond the first seal portion 32, 52 and the resin member 70 together so as to cause cohesive failure. [Explanation of symbols]

[0056] 1. Battery (energy storage device) 10 cases 30 Case cover member (case member) 30h Insertion hole 31 (case lid member) case seal (seal) 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 lid) 36p particles (derived from the metal that makes up the case cover) 40 Electrode body 50 Terminal material (metal material) 51 (Terminal member) terminal seal portion (seal portion) 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 Nanopillar (of terminal material) 56p particles (derived from the metal that makes up 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 (nanopillar) height 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 annular 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 near 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 three or more first seal portions that are annular and continuous around the entire circumferential direction of the seal portion, and that undergo cohesive failure when the bond with the resin member is broken; and second seal portions each arranged between the first seal portions adjacent in the width direction of the seal portion, each having an annular shape extending over the entire circumferential direction of the seal portion, and which undergo interface failure when the bond with the resin member is broken. Energy storage device.

2. The electricity storage device according to claim 1 , The three or more first seal portions are Particles derived from the metal constituting the case member or the terminal member are linked together in a string to form columnar nanopillars with a height of 20 nm or more, and the spaces between these nanopillars are filled with a resin material constituting the resin member. Energy storage device.

3. a case member having an insertion hole and including a band-shaped annular 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 near the insertion hole; 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, At least one of the case seal and the terminal seal is three or more first seal portions that are annular and continuous around the entire circumferential direction of the seal portion, and that undergo cohesive failure when the bond with the resin member is broken; and second seal portions each arranged between the first seal portions adjacent in the width direction of the seal portion, each having an annular shape extending over the entire circumferential direction of the seal portion, and which undergo interface 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 three or more of the first seal portions and the second seal portions in at least one of the case member and the terminal member; a resin forming step of forming the resin member joined to the seal portion after the seal portion forming step. A method for manufacturing an electricity storage device.

4. A method for manufacturing the electricity storage device according to claim 3, The three or more first seal portions are nanopillars each having a height of 20 nm or more are formed by particles derived from a metal constituting the case member or the terminal member being linked together in a string-like pattern, and a resin material constituting the resin member is filled between these nanopillars; The seal portion forming step includes: intermittently irradiating the seal portion with pulsed laser light while shifting the irradiation position to form three or more first seal portions each including a forest of nanopillars; The resin forming step includes: The resin member is formed while filling the spaces between the nano-columns standing in the three or more first sealing portions with the resin material. A method for manufacturing an electricity storage device.

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