Power storage device and method for manufacturing the same

Abstract

To provide a power storage device in which cracks are unlikely to occur near a pair of longitudinal joint surfaces of a resin inner part of a resin member even when the power storage device is placed at a low temperature of -40°C.SOLUTION: A power storage device 1 includes a case lid member 30, terminal members 50, 60, and resin members 70, 80. The resin members 70, 80 have resin outer parts 71, 81, resin inner parts 73, 83, and resin hole interiors 72, 82, and when the case lid member 30 and the resin members 70, 80 are placed in a temperature environment of -40°C, a convex warp WA is generated in the resin members 70, 80 on the outer side FH1 in the lid thickness direction FH in the lid longitudinal direction DH, and a pair of longitudinal side joining surfaces 73ma, 83ma of the resin inner parts 73, 83 press the terminal members 50, 60 in the lid longitudinal direction DH.SELECTED DRAWING: Figure 6

Description

[Technical field]

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

[0002] As an electricity 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 lid member constituting a rectangular box-like case. Specifically, the positive and negative terminal members are inserted into insertion holes provided in the case lid member and extend from the inside to the outside of the case, and the resin member hermetically joins the case lid member and the terminal members while insulating them from each other, and fixes the terminal members to the case lid member. Such a battery is disclosed, for example, in Patent Document 1 (see Figures 2, 6, 7, etc.). [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] In the above-mentioned battery, when the battery is placed in an extremely low-temperature environment, for example, -40°C, a crack (fissure) may occur along the boundary of the resin member near the boundary with the terminal member due to cohesive failure. Specifically, the resin member has a resin outer part located on the outside of the case lid member in the lid thickness direction, a resin inner part located on the inside of the case lid member in the lid thickness direction, and a resin hole interior located in the insertion hole of the case lid member and integrally connected to these. Furthermore, the bonding surface of the resin inner part bonded to the terminal member has a pair of long-side bonding surfaces facing the long direction of the lid and a pair of short-side bonding surfaces facing the short direction of the lid. It has been found that the above-mentioned cracks may occur near the pair of long-side bonding surfaces of the resin inner part.

[0005] The reason for this is that when the battery is placed at a low temperature of -40°C, the resin member develops a convex warp on the inside in the lid thickness direction in the lid longitudinal direction (hereinafter, simply referred to as "inwardly convex warp"). When such an inwardly convex warp develops in the resin member, the inside resin part deforms in the lid longitudinal direction in a direction away from the terminal member, and it is believed that cohesive failure occurs near each of the pair of longitudinal joint surfaces, causing cracks.

[0006] The present invention has been made in consideration of the current situation, and provides an electricity storage device in which cracks are less likely to occur near a pair of long side joining surfaces of the resin inner part of the resin member, even when the electricity storage device is placed at a low temperature of -40°C, and a method for manufacturing the electricity storage device. [Means for solving the problem]

[0007] (1) One aspect of the present invention for solving the above problem is an electric storage device comprising: a case lid member having an insertion hole and extending in a lid longitudinal direction; a terminal member inserted into the insertion hole of the case lid member; and a resin member that hermetically joins the case lid member and the terminal member while insulating them from each other and fixing the terminal member to the case lid member, wherein the resin member has a resin outer portion located on the outside of the case lid member in a lid thickness direction, a resin inner portion located on the inside of the case lid member in the lid thickness direction, and a resin member that is located within the insertion hole of the case lid member and is integrally connected to the resin outer portion and the resin inner portion. the terminal member extends inward in the thickness direction of the lid through the resin outer portion, the resin hole interior, and the resin inner portion, the resin inner portion of the resin member faces in the longitudinal direction of the lid and includes a pair of longitudinal side joint surfaces joined to the terminal member, and the case lid member and the resin member are configured such that, when the electricity storage device is placed in a temperature environment of -40°C, a convex warp is generated in the resin member outward in the thickness direction of the lid in the longitudinal direction of the lid, and the pair of longitudinal side joint surfaces of the resin inner portion each press the terminal member in the longitudinal direction of the lid.

[0008] In the above-described power storage device, when the power storage device is placed at a low temperature of -40°C, the resin member, contrary to the above, generates a convex warp in the outer side in the lid thickness direction with respect to the lid longitudinal direction (hereinafter, also simply referred to as "convex warp on the outer side"). Then, among the inner resin parts, the pair of longitudinal joint surfaces press the terminal members in the lid longitudinal direction. For this reason, near the pair of longitudinal joint surfaces among the inner resin parts, cohesive failure can be suppressed from occurring and cracks can be prevented from forming. Therefore, even when the power storage device is placed at a low temperature of -40°C, the above-described power storage device is less likely to have cracks near the pair of longitudinal joint surfaces among the inner resin parts of the resin member.

[0009] Note that examples of the "power storage device" include secondary batteries such as lithium-ion secondary batteries, sodium-ion secondary batteries, calcium-ion secondary batteries, and capacitors such as lithium-ion capacitors.

[0010] (2) The power storage device according to (1), wherein the resin member is preferably a power storage device in which the volume V1 of the outer resin part is larger than the volume V2 of the inner resin part (V1 > V2).

[0011] When the volume V2 of the inner resin part is larger than the volume V1 of the outer resin part of the resin member (V1 < V2), when the power storage device is placed at a low temperature of -40°C, the resin member is likely to generate the above-described convex warp on the inner side. On the contrary, in the above-described power storage device, since the volume V1 of the outer resin part of the resin member is made larger than the volume V2 of the inner resin part (V1 > V2), a power storage device in which the resin member generates a convex warp on the outer side at a low temperature of -40°C can be easily configured.

[0012] (3) In the energy storage device described in either (1) or (2), it is preferable that the terminal seal portion of the terminal member to which the resin member is hermetically joined has a forest of terminal nanopillars with a height of 50 nm or more on its surface, the terminal nanopillars being formed by particles with a diameter of 100 nm or less derived from the metal constituting the terminal member being linked in a string-like manner, and the resin member is hermetically joined to the terminal seal portion by filling the spaces between the forest of terminal nanopillars with resin material constituting the resin member.

[0013] In the above-mentioned power storage device, the above-mentioned terminal nano-pillars stand in a forest on the surface of the terminal seal part of the terminal member, and a resin material is filled between these terminal nano-pillars to hermetically bond the resin member to the terminal seal part. This increases the bonding strength between the terminal seal part of the terminal member and the resin member, and makes it possible to maintain good sealing performance between the terminal member and the resin member.

[0014] Examples of "particles derived from the metal constituting the terminal member" constituting the terminal nanopillar include particles made of the above metals, particles made of oxides of the above metals, particles made of the above metals and oxides of the above metals, etc. Also included are particles containing nitrides of the above metals, such as particles made of the above metals, oxides of the above metals, and nitrides of the above metals. The "terminal seal portion" may be provided on the entire terminal joint portion of the terminal member that is joined to the resin member, or may be provided on only a part of the terminal joint portion.

[0015] (4) Still another aspect includes a case lid member having an insertion hole and extending in a lid longitudinal direction, a terminal member inserted into the insertion hole of the case lid member, and a resin member that hermetically joins the case lid member and the terminal member while insulating them from each other and fixing the terminal member to the case lid member, wherein the resin member has a resin outer portion located on the outside of the case lid member in the lid thickness direction, a resin inner portion located on the inside of the case lid member in the lid thickness direction, and a resin hole interior located within the case lid member insertion hole and integrally connected to the resin outer portion and the resin inner portion, and the terminal member extends in the lid thickness direction by penetrating the resin outer portion, the resin hole interior, and the resin inner portion. a resin inner portion of the resin member extending inward in the lid longitudinal direction, the resin inner portion of the resin member including a pair of longitudinal side joint surfaces facing the lid longitudinal direction and joined to the terminal member, the case lid member and the resin member being configured such that, when the electricity storage device is placed in a temperature environment of -40°C, a convex warp is generated in the resin member outward in the lid thickness direction in the lid longitudinal direction, and the pair of longitudinal side joint surfaces of the resin inner portion each press the terminal member in the lid longitudinal direction, the method for manufacturing an electricity storage device comprising: an insert molding process for insert molding the resin member with the terminal member inserted into the insertion hole of the case lid member.

[0016] In the manufacturing method of the above-mentioned electricity storage device, the resin member is insert molded in the insert molding process, so that it is possible to easily manufacture an electricity storage device in which the resin member develops the above-mentioned outward convex warp at a low temperature of -40°C.

[0017] (5) In the method for manufacturing an electricity storage device described in (4), the insert molding process may be a method for manufacturing an electricity storage device in which the resin member is molded so that the volume V1 of the outer resin portion is larger than the volume V2 of the inner resin portion (V1>V2).

[0018] In the manufacturing method for the above-mentioned energy storage device, a resin member is molded in which the volume V1 of the outer resin portion is larger than the volume V2 of the inner resin portion, so that an energy storage device in which the resin member develops the aforementioned outward convex warp at a low temperature of -40°C can be easily manufactured.

[0019] (6) A method for manufacturing an electricity storage device according to (4) or (5), wherein the terminal member, the terminal seal portion to which the resin member is airtightly joined, has a surface on which terminal nanopillars of 50 nm or more in height stand, the terminal nanopillars being formed by particles of 100 nm or less in diameter derived from the metal constituting the terminal member being linked in a string-like pattern, and the resin member is airtightly joined to the terminal seal portion by filling the spaces between the forest of terminal nanopillars with a resin material constituting the resin member, and the resin member is airtightly joined to the terminal seal portion; the method may further include a terminal nanopillar formation step, prior to the insert molding step, of irradiating the terminal seal portion of the terminal member with a pulsed laser beam while shifting the irradiation position, to form the forest of terminal nanopillars in the terminal seal portion, and the insert molding step may be a method for manufacturing an electricity storage device in which the resin member is molded while filling the spaces between the forest of terminal nanopillars of the terminal seal portion with the resin material.

[0020] In the above-mentioned method for manufacturing an electricity storage device, the above-mentioned terminal nano-pillars are formed on the surface of the terminal seal part by irradiating laser light as described above in the terminal nano-pillar formation step, so that the terminal nano-pillars can be easily formed in the terminal seal part. Then, in the insert molding step, the resin member is molded while filling the spaces between the terminal nano-pillars with resin material, so that the bonding strength between the terminal seal part of the terminal member and the resin member can be increased and the sealing performance between the terminal member and the resin member can be well maintained. [Brief description of the drawings]

[0021] [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]1A is a partially enlarged plan view of the resin member that fixes the terminal member to the case lid member according to an embodiment, and FIG. 1B is a partially enlarged plan view of the resin member that fixes the terminal member to the case lid member according to an embodiment, where FIG. 1A is a partially enlarged plan view of the resin member as seen from the outside in the thickness direction of the lid, and FIG. 1B is a partially enlarged plan view of the resin member as seen from the inside in the thickness direction of the lid. [Figure 4] 3A is a cross-sectional view taken along the line AA in FIG. 3A, along the longitudinal direction of the lid and the thickness direction of the lid; and FIG. 3B is a cross-sectional view taken along the line BB in FIG. 3B, along the transverse direction of the lid and the thickness direction of the lid. [Diagram 5] 2 is a partially enlarged cross-sectional view showing terminal nano-pillars (lid nano-pillars) standing in rows on the surface of the terminal seal portion (lid seal portion) in the embodiment. FIG. [Figure 6] 4A and 4B are explanatory diagrams showing the state of the resin members etc. when the battery according to the embodiment is placed at a low temperature of -40°C, where FIG. 4A corresponds to the cross-sectional view of FIG. 4A and FIG. 3B corresponds to the plan view of FIG. 3B. [Figure 7] 2 is a flowchart of a method for manufacturing a battery according to an embodiment. [Figure 8] FIG. 2 is an explanatory diagram showing a terminal nanopillar forming step (lid nanopillar forming step) in the battery manufacturing method according to the embodiment. [Figure 9] 5A and 5B are explanatory views of an insert molding process in a manufacturing method for a battery according to an embodiment, where FIG. 5A shows a state in which a terminal member is inserted into an insertion hole in a case lid member, and FIG. 5B shows a state in which a resin member is molded. [Figure 10] 6(a) and 6(b) are explanatory diagrams showing the state of the resin members, etc. when a battery according to a comparative embodiment is placed at a low temperature of -40°C, where FIG. 6(a) is an explanatory diagram corresponding to FIG. 6(a) and FIG. 6(b) is an explanatory diagram corresponding to FIG. 6(b). DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] 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 plan view of the vicinity of the resin members 70, 80 that fix the terminal members 50, 60 to the case lid member 30, and FIG. 4 shows a partially enlarged plan view. FIG. 5 shows a partially enlarged cross-sectional view of the terminal nano-pillars 57, 67, etc. that stand in a forest on the surfaces 55m, 65m of the terminal seal parts 55, 65. In the following description, the battery height direction AH, battery width direction BH, and battery thickness direction CH of the battery 1, and the lid longitudinal direction DH, lid short-side direction EH, and lid thickness direction FH of the case lid member 30 are defined as the directions shown in FIG. 1 to FIG. 4.

[0023] The 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, a positive electrode terminal member 50 fixed to the case 10 via a resin member 70, and a negative electrode terminal member 60 fixed to the case 10 via a resin member 80. The electrode body 40 is covered in the case 10 by a bag-shaped insulating holder 7 made of an insulating film. An electrolyte 5 is housed in 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.

[0024] The case 10 is a rectangular parallelepiped 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 having a rectangular opening 20c and accommodating the electrode body 40 therein, and a rectangular plate-like case lid 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 around the entire periphery. Case lid member 30 of case 10 is provided with a safety valve 11 that breaks and opens when the internal pressure of case 10 exceeds a valve opening pressure. Case lid member 30 is also provided with a liquid injection hole 30k that penetrates case lid member 30 in the lid thickness direction FH, and this liquid injection hole 30k is airtightly sealed with a disk-shaped sealing member 12 made of aluminum.

[0025] The electrode assembly 40 housed in the case 10 is a rectangular parallelepiped laminated type, in which a plurality of positive electrode plates 41 and a plurality of negative electrode plates 42 are alternately laminated in the battery thickness direction CH with separators 43 made of porous resin films interposed between them. The positive electrode plates 41, the negative electrode plates 42, and the separators 43 each have a rectangular shape extending in the battery height direction AH and the battery width direction BH. The positive electrode plate 41 is composed of a positive electrode current collector foil made of aluminum foil and a positive electrode active material layer containing positive electrode active material particles formed on both main surfaces of the positive electrode current collector foil. A part of the positive electrode current collector foil extends to one side BH1 in the battery width direction BH, and the positive electrode active material layer is not present on both sides, forming a positive electrode foil exposed portion. The positive electrode foil exposed portions of each positive electrode plate 41 overlap in the foil thickness direction to form a positive electrode current collector portion 40c. The positive electrode current collector portion 40c is electrically connected to a positive electrode terminal member 50 described later.

[0026] The negative electrode plate 42 is composed of a negative electrode current collector foil made of copper foil and a negative electrode active material layer containing negative electrode active material particles formed on both main surfaces of the negative electrode current collector foil. A part of the negative electrode current collector foil extends to the other side BH2 in the battery width direction BH, and is an exposed negative electrode foil portion on both sides of the negative electrode current collector foil without the negative electrode active material layer. The negative electrode foil exposed portions of the negative electrode plates 42 overlap in the foil thickness direction to form a negative electrode current collector 40d. The negative electrode current collector 40d is electrically connected to a negative electrode terminal member 60 described later.

[0027] The case lid member 30 has rectangular insertion holes 30h1 and 30h2 near the ends of one side DH1 and the other side DH2 in the lid longitudinal direction DH (one side BH1 and the other side BH2 in the battery width direction BH), which penetrate the case lid member 30 in the lid thickness direction FH. A positive electrode terminal member 50 made of aluminum is inserted into one of the insertion holes 30h1, 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 60 made of copper is inserted into the other insertion hole 30h2, and the terminal member 60 is fixed to the case lid member 30 in a state insulated from the case lid member 30 via a resin member 80.

[0028] First, the resin members 70, 80 will be described. The resin members 70, 80 are joined to the case lid member 30 and the terminal members 50, 60 while insulating the case lid member 30 and the terminal members 50, 60, and fix the terminal members 50, 60 to the case lid member 30. Specifically, the resin members 70, 80 are airtightly joined to the terminal seal parts 55, 65 by filling the spaces between the standing terminal nano pillars 57, 67 of the terminal seal parts 55, 65 of the terminal members 50, 60 (see FIG. 5). The resin members 70, 80 are airtightly joined to the lid seal parts 31, 32 by filling the spaces between the standing lid nano pillars 37 of the lid seal parts 31, 32 of the case lid member 30 (see FIG. 5).

[0029] The resin members 70, 80 are composed of a resin outer portion 71, 81, a resin inner portion 73, 83, and a resin hole interior portion 72, 82 located between the resin outer portion 71, 81, a resin inner portion 73, 83, and a resin hole interior portion 72, 82 that is integrally connected to the resin outer portion 71, 81 (molded integrally). The resin outer portion 71, 81 is a portion located on the outer side FH1 (upper side AH1 in the battery height direction AH) of the lid thickness direction FH of the case lid member 30. The resin inner portion 73, 83 is a portion located on the inner side FH2 (lower side AH2 in the battery height direction AH) of the lid thickness direction FH of the case lid member 30, and has a pair of long-side joint surfaces 73ma, 83ma that face the lid longitudinal direction DH (battery width direction BH) and are joined to the terminal members 50, 60, and a pair of short-side joint surfaces 73mb, 83mb that face the lid transverse direction EH (battery thickness direction CH) and are joined to the terminal members 50, 60. Moreover, the resin hole interiors 72, 82 are portions located within the insertion holes 30h1, 30h2 of the case lid member 30. In this embodiment, the volume V1 of the resin outer parts 71, 81 is larger than the volume V2 of the resin inner parts 73, 83 (V1>V2). Specifically, the volume V1 of the resin outer parts 71, 81 is approximately 1.5 times the volume V2 of the resin inner parts 73, 83.

[0030] The resin members 70, 80 are made of a resin material 75 containing a thermoplastic main resin, a thermoplastic elastomer, and a filler. In this embodiment, the main resin is polyphenylene sulfide (PPS), the elastomer is a thermoplastic polyurethane elastomer, and the filler is a fibrous glass filler (approximately 10 μm in diameter × 300 μm in length). The linear expansion coefficient α1 of this resin material 75 in the temperature range of −40 to 65° C. is α1=2.0×10 -5 (1 / K). As described above, the case lid member 30 is made of aluminum, and has a linear expansion coefficient α2 in the temperature range of −40 to 65° C., which is α2=2.4×10 -5 Since it is (1 / K), the linear expansion coefficient α2 of the metal (aluminum) forming the case lid member 30 is larger than the linear expansion coefficient α1 of the resin material 75 forming the resin members 70, 80.

[0031] Next, the terminal members 50, 60 will be described. The terminal members 50, 60 are formed by pressing metal plates (aluminum plate for the positive electrode, copper plate for the negative electrode). The terminal members 50, 60 extend through the resin outer parts 71, 81, resin hole interiors 72, 82, and resin inner parts 73, 83 of the resin members 70, 80 to the inner side FH2 (lower side AH2) in the lid thickness direction FH. The terminal members 50, 60 are composed of terminal outer parts 51, 61, terminal hole interiors 52, 62, terminal inner parts 53, 63, and terminal extension parts 54, 64.

[0032] The terminal outer parts 51, 61 are located on the outer side FH1 in the lid thickness direction FH of the case lid member 30, and are portions that are joined to the resin outer parts 71, 81 of the resin members 70, 80. The terminal outer parts 51, 61 are made up of rectangular plate-shaped top plate parts 51p, 61p that extend in the lid longitudinal direction DH and the lid short-side direction EH, and extension parts 51q, 61q that bend at the end of one side EH1 in the lid short-side direction EH of the top plate parts 51p, 61p (one side CH1 in the battery thickness direction CH) and extend to the inner side FH2 in the lid thickness direction FH. The terminal hole interiors 52, 62 are located within the insertion holes 30h1, 30h2 of the case lid member 30, and are joined to the resin hole interiors 72, 82 of the resin members 70, 80.

[0033] The terminal inside portions 53, 63 are located on the inside FH2 in the lid thickness direction FH of the case lid member 30, and are portions that are joined to the resin inside portions 73, 83 of the resin members 70, 80. In detail, a pair of long side joining surfaces 73ma, 83ma of the resin inside portions 73, 83 are joined to the terminal inside portions 53, 63 in the lid longitudinal direction DH, and a pair of short side joining surfaces 73mb, 83mb of the resin inside portions 73, 83 are joined to the terminal inside portions 53, 63 in the lid short side direction EH. The terminal extensions 54, 64 extend further from the terminal inner parts 53, 63 toward the lower side AH2 and protrude from the resin members 70, 80 toward the lower side AH2. The positive terminal extension 54 is welded to the positive current collector 40c of the electrode body 40 at the tip of the lower side AH2 and is conductively connected to the positive current collector 40c. The negative terminal extension 64 is welded to the negative current collector 40d of the electrode body 40 at the tip of the lower side AH2 and is conductively connected to the negative current collector 40d.

[0034] In this embodiment, the extending portions 51q, 61q of the terminal outer portions 51, 61, the terminal hole interiors 52, 62, and the terminal inner portions 53, 63 of the terminal members 50, 60 form terminal seal portions 55, 65 to which the resin members 70, 80 are hermetically joined. As shown in Fig. 5, on the surfaces 55m, 65m of the terminal seal portions 55, 65 (the surfaces of the extending portions 51q, 61q of the terminal outer portions 51, 61, the surfaces of the terminal hole interiors 52, 62, and the surfaces of the terminal inner portions 53, 63), terminal nano-pillars 57, 67 formed by linking together particles 57p, 67p derived from the metals (aluminum for the positive electrode and copper for the negative electrode) constituting the terminal members 50, 60 in a string-like manner are arranged.

[0035] Specifically, the positive electrode terminal nanopillars 57 are composed of particles 57p made of aluminum and aluminum oxide, and the negative electrode terminal nanopillars 67 are composed of particles 67p made of copper and copper oxide. The particles 57p, 67p have a diameter Da of 100 nm or less (in this embodiment, Da = 30 nm approximately), and the terminal nanopillars 57, 67 have a height ha of 50 nm or more, or even 300 nm or more (in this embodiment, ha = 500 nm approximately). The resin members 70, 80 are hermetically bonded to the terminal seal parts 55, 65 with a resin material 75 filled between the forest of terminal nanopillars 57, 67.

[0036] In addition, the resin members 70, 80 are airtightly joined to the lid seal parts 31, 32 (see FIG. 4) surrounding the insertion holes 30h1, 30h2 of the case lid member 30. Specifically, the lid seal parts 31, 32 have rectangular band-shaped outer side surfaces 31m, 32m facing the outside FH1 (upper side AH1) in the lid thickness direction FH, and rectangular band-shaped inner side surfaces 31n, 32n facing the inside FH2 (lower side AH2) in the lid thickness direction FH. On these surfaces, like the surface 55m of the positive electrode terminal seal part 55 (see FIG. 5), lid nano-pillars 37 are formed by combining particles 37p made of aluminum and aluminum oxide in a string-like manner. The diameter Da of the particles 37p is 100 nm or less (in this embodiment, Da = 30 nm approximately), and the height ha of the lid nanopillars 37 is 50 nm or more, or even 300 nm or more (in this embodiment, ha = 500 nm approximately). The resin members 70, 80 are hermetically bonded to the lid seal portions 31, 32 with a resin material 75 filled between the adjacent lid nanopillars 37.

[0037] In the battery 1 of this embodiment, the case lid member 30 and the resin members 70, 80 are configured as follows. That is, when the battery 1 is placed in a temperature environment of -40°C (see FIG. 6), a convex warp WA occurs in the resin members 70, 80 on the outer side FH1 of the lid thickness direction FH in the lid longitudinal direction DH. A pair of longitudinal side joint surfaces 73ma, 83ma of the resin inner parts 73, 83 of the resin members 70, 80 are configured to press the terminal members 50, 60 in the lid longitudinal direction DH, respectively.

[0038] The reason why the convex warpage WA occurs on the outer side FH1 of the resin members 70, 80 is considered to be as follows. That is, in this embodiment, as described above, the linear expansion coefficient α2 of the metal (aluminum) constituting the case lid member 30 is larger than the linear expansion coefficient α1 of the resin material 75 constituting the resin members 70, 80. Therefore, when the battery 1 is placed at a low temperature of -40°C, the case lid member 30 shrinks more in the lid longitudinal direction DH than the resin members 70, 80. Meanwhile, since the resin members 70, 80 and the case lid member 30 are joined to each other, the resin members 70, 80 and the case lid member 30 are curved and deformed due to this difference in thermal contraction, just like a bimetal is deformed. Since the volume V1 of the resin outer portions 71, 81 of the resin members 70, 80 is larger than the volume V2 of the resin inner portions 73, 83, it is believed that the influence of the resin outer portions 71, 81 is greater than that of the resin inner portions 73, 83, causing the resin members 70, 80 and the case lid member 30 to develop a convex warp WA on the outside FH1.

[0039] Here, the configuration of the case lid member 930 and the resin members 970, 980 in the battery of the comparative embodiment will be described (see FIG. 10). When the battery of the comparative embodiment is placed in a temperature environment of −40° C., a convex warp WB occurs on the inner side FH2 (lower side AH2) of the lid thickness direction FH in the lid longitudinal direction DH in the resin members 970, 980, contrary to the battery 1 of the present embodiment. When such a convex warp WB occurs on the inner side FH2 in the resin members 970, 980, the resin inner parts 973, 983 deform in the direction away from the terminal members 950, 960 in the lid longitudinal direction DH, and cohesive failure occurs near a pair of longitudinal side joint surfaces 973ma, 983ma, respectively, forming cracks KR.

[0040] In contrast, in the battery 1 of this embodiment, as described above, a convex warp WA occurs on the outer side FH1 of the resin members 70, 80 at a low temperature of -40°C. Then, a pair of longitudinal joint surfaces 73ma, 83ma of the resin inside parts 73, 83 of the resin members 70, 80 press the terminal members 50, 60 in the lid longitudinal direction DH, respectively. Therefore, it is possible to suppress the occurrence of cohesive failure and the occurrence of cracks KR in the vicinity of the pair of longitudinal joint surfaces 73ma, 83ma of the resin inside parts 73, 83. Therefore, even if the battery 1 is placed at a low temperature of -40°C, cracks KR are unlikely to occur in the vicinity of the pair of longitudinal joint surfaces 73ma, 83ma of the resin inside parts 73, 83 of the resin members 70, 80. Furthermore, in this embodiment, the volume V1 of the resin outer portions 71, 81 of the resin members 70, 80 is larger than the volume V2 of the resin inner portions 73, 83 (V1>V2), so that a battery 1 can be easily constructed in which the resin members 70, 80 develop a convex warp WA on the outer side FH1 at a low temperature of -40°C.

[0041] Furthermore, in this embodiment, terminal nano-pillars 57, 67 stand in rows on the surfaces 55m, 65m of the terminal seal portions 55, 55 of the terminal members 50, 60, and resin material 75 is filled between these terminal nano-pillars 57, 67 to hermetically bond the resin members 70, 80 to the terminal seal portions 55, 65. This increases the bonding strength between the terminal seal portions 55, 65 of the terminal members 50, 60 and the resin members 70, 80, and makes it possible to maintain good sealing performance between the terminal members 50, 60 and the resin members 70, 80.

[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 punching an aluminum plate into a predetermined shape and forming the liquid injection hole 30k, the insertion holes 30h1, 30h2, and the safety valve 11 therein. In addition, unroughened terminal members 50Z, 60Z are prepared. The unroughened positive terminal member 50Z is obtained by punching an aluminum plate into a predetermined shape and bending it. In addition, the unroughened negative terminal member 60Z is obtained by punching a copper plate into a predetermined shape and bending it.

[0043] Then, in the "terminal nanopillar formation step S1" (see Fig. 7), the terminal seal portions 55, 65 of the terminal members 50Z, 60Z are irradiated with pulsed laser light LC while shifting the irradiation position (see Fig. 8), to form terminal nanopillars 57, 67 standing in a forest on the surfaces 55m, 65m of the terminal seal portions 55, 65. As described above (also see Fig. 5), the terminal nanopillars 57, 67 are formed by particles 57p, 67p being linked together in a string-like shape to form a pillar.

[0044] In this embodiment, the irradiation conditions of the positive electrode laser are 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 Db of 80 μm. The irradiation conditions of the negative electrode laser are 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 Db of 75 μm. In the terminal seal portion 55, 65, in the circular portion in plan view irradiated with the laser light LC, the metal (aluminum for the positive electrode, copper for the negative electrode) near the surfaces 55m, 65m melts and becomes steam. After that, when the temperature of the steam decreases, it becomes particles 57p, 67p (particles 57p of aluminum and aluminum oxide for the positive electrode, and particles 67p of copper and copper oxide for the negative electrode) and accumulates on the surfaces 55m, 65m of the terminal seal portion 55, 65. By irradiating the terminal seal portions 55, 65 with the laser beam LC while shifting the irradiation position, the particles 57p, 67p are deposited in a string-like manner and bonded to form columns, thereby forming terminal nano-pillars 57, 67 standing in a forest.

[0045] Separately, in a "lid nanopillar formation step S2" (see FIG. 7), a pulsed laser beam LC is irradiated onto the lid seal portions 31, 32 of the case lid member 30Z while shifting the irradiation position (see FIG. 8), to form forests of lid nanopillars 37 on the outer surfaces 31m, 32m and inner surfaces 31n, 32n of the lid seal portions 31, 32. As described above (also see FIG. 5), the lid nanopillars 37 are formed by particles 37p made of aluminum and aluminum oxide linked together in a string-like shape to form columns. In this embodiment, the laser irradiation conditions are the same as those used for forming the terminal nanopillars 57 on the positive electrode terminal seal portion 55 in the terminal nanopillar formation step S1.

[0046] Next, in the "insert molding process S3" (see FIG. 7), the resin members 70, 80 are insert molded using the above-mentioned resin material 75 with the terminal members 50, 60 inserted into the insertion holes 30h1, 30h2 of the case lid member 30 (see FIG. 9). Specifically, the insert molding process 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 terminal members 50, 60 are inserted into the insertion holes 30h1, 30h2 of the case lid member 30 (see FIG. 9(a)). Thereafter, the upper die is moved toward the lower die to close the molding die.

[0047] Next, the molten resin material 75 is injected into the cavity of the molding die. At this time, the resin material 75 is filled between the terminal nano pillars 57, 67 of the terminal seal parts 55, 65 and between the lid nano pillars 37 of the lid seal parts 31, 32, and the resin members 70, 80 that are airtightly bonded to the terminal seal parts 55, 65 and the lid seal parts 31, 32 are molded (see FIG. 9(b)). The cavity of the molding die is shaped so that the volume V1 of the resin outer parts 71, 81 is larger than the volume V2 of the resin inner parts 73, 83, thereby molding the resin members 70, 80 in a form in which the volume V1 of the resin outer parts 71, 81 is larger than the volume V2 of the resin inner parts 73, 83. Thereafter, the lid assembly 15 in which the terminal members 50, 60 are fixed to the case lid member 30 via the resin members 70, 80 is taken out of the molding die.

[0048] Next, in the "electrode body connecting process 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 54 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. Also, the terminal extension 64 of the negative electrode terminal member 60 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. 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.

[0049] 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.

[0050] As described above, in the manufacturing method of battery 1, the resin members 70, 80 are insert molded in the insert molding process S3, so that a battery 1 in which the resin members 70, 80 generate a convex warp WA on the outer FH1 at a low temperature of -40°C can be easily manufactured. Furthermore, in this embodiment, the resin members 70, 80 are molded in such a way that the volume V1 of the resin outer portions 71, 81 is larger than the volume V2 of the resin inner portions 73, 83, so that a battery 1 can be easily manufactured in which the resin members 70, 80 develop a convex warp WA on the outer side FH1 at a low temperature of -40°C.

[0051] Furthermore, since the terminal nanopillars 57, 67 are formed on the surfaces 55m, 65m of the terminal seal parts 55, 65 by irradiating them with laser light LC in the terminal nanopillar formation step S1, it is possible to easily form the terminal nanopillars 57, 67 in the terminal seal parts 55, 65. Then, since the resin members 70, 80 are molded while filling the spaces between the terminal nanopillars 57, 67 with resin material 75 in the insert molding step S3, it is possible to increase the bonding strength between the terminal seal parts 55, 65 of the terminal members 50, 60 and the resin members 70, 80 and to maintain good sealing performance between the terminal members 50, 60 and the resin members 70, 80.

[0052] 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. [Explanation of symbols]

[0053] 1. Battery (energy storage device) 10 Cases 30 Case cover member 30h1, 30h2 Through holes 40 Electrode body 50,60 Terminal material 55,65 Terminal seal part 55m, 65m (Terminal seal part) surface 57,67 Terminal Nano Pillar 57p,67p particles 70,80 Resin material 71,81 Resin outer part 72,82 Inside the resin hole 73,83 Resin inner part 73ma, 83ma Long side joint surface 73mb,83mb Short side joint surface DH Lid length direction EH Lid short side direction FH Lid thickness direction FH1 (lid thickness direction) outside FH2 (lid thickness direction) inside V1 (Outer resin volume) V2 (Inner resin volume) WA (outward convex warp in the lid thickness direction in the lid longitudinal direction) WB (Convex inward warp in the lid thickness direction in the lid length direction) KR Crack LC Laser Light S1 Terminal nano pillar formation process S3 Insert molding process

Claims

1. a case lid member having an insertion hole and extending in a lid longitudinal direction; a terminal member inserted into the insertion hole of the case lid member; a resin member that hermetically bonds the case lid member and the terminal member while insulating them from each other and fixes the terminal member to the case lid member. An electricity storage device, The resin member is a resin outer portion located on an outer side of the case lid member in a lid thickness direction; a resin inner portion located on an inner side of the case lid member in the lid thickness direction; a resin hole interior located within the insertion hole of the case lid member and integrally connected to the resin outer portion and the resin inner portion, The terminal member is the resin outer portion, the resin hole interior, and the resin inner portion extend inward in the lid thickness direction, The resin inner portion of the resin member is The cover includes a pair of longitudinal joint surfaces that face in a longitudinal direction of the cover and are joined to the terminal member, The case lid member and the resin member are When the power storage device is placed in a temperature environment of −40° C., A convex warp is generated on the resin member on an outer side in the thickness direction of the lid with respect to the longitudinal direction of the lid, The pair of longitudinal side joint surfaces of the resin inner portion are configured to press the terminal member in the longitudinal direction of the lid. Energy storage device.

2. The power storage device according to claim 1 , The resin member is The volume V1 of the outer resin portion is greater than the volume V2 of the inner resin portion (V1>V2). Energy storage device.

3. The electricity storage device according to claim 1 or 2, The terminal member includes a terminal seal portion to which the resin member is hermetically joined, On the surface of the terminal member, terminal nano-pillars having a height of 50 nm or more are formed by connecting particles having a diameter of 100 nm or less derived from the metal constituting the terminal member in a string-like manner to form pillars, The resin member is The resin material constituting the resin member is filled between the adjacent ones of the terminal nano-pillars, and the resin material is airtightly bonded to the terminal seal portion. Energy storage device.

4. a case lid member having an insertion hole and extending in a lid longitudinal direction; a terminal member inserted into the insertion hole of the case lid member; a resin member that hermetically bonds the case lid member and the terminal member while insulating them from each other and fixes the terminal member to the case lid member, The resin member is a resin outer portion located on an outer side of the case lid member in a lid thickness direction; a resin inner portion located on an inner side of the case lid member in the lid thickness direction; a resin hole interior located within the insertion hole of the case lid member and integrally connected to the resin outer portion and the resin inner portion, The terminal member is the resin outer portion, the resin hole interior, and the resin inner portion extend inward in the lid thickness direction, The resin inner portion of the resin member is The cover includes a pair of longitudinal joint surfaces that face in a longitudinal direction of the cover and are joined to the terminal member, The case lid member and the resin member are When the power storage device is placed in a temperature environment of −40° C., A convex warp is generated on the resin member on an outer side in the thickness direction of the lid with respect to the longitudinal direction of the lid, The pair of longitudinal side joint surfaces of the resin inner portion are configured to press the terminal member in the longitudinal direction of the lid. A method for manufacturing an electricity storage device, comprising: and an insert molding step of insert-molding the resin member in a state where the terminal member is inserted into the insertion hole of the case lid member. 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 insert molding process includes: The resin member is molded so that the volume V1 of the outer resin portion is larger than the volume V2 of the inner resin portion (V1>V2). A method for manufacturing an electricity storage device.

6. A method for producing the electricity storage device according to claim 4 or 5, comprising the steps of: The terminal member includes a terminal seal portion to which the resin member is hermetically joined, On the surface of the terminal member, terminal nano-pillars having a height of 50 nm or more are formed by connecting particles having a diameter of 100 nm or less derived from the metal constituting the terminal member in a string-like manner to form pillars, The resin member is a resin material constituting the resin member is filled between the adjacent ones of the terminal nano-pillars standing in a row, and the spaces between the adjacent ones of the terminal nano-pillars are hermetically joined to the terminal seal portion; a terminal nano-pillar forming step of irradiating the terminal seal portion of the terminal member with a pulsed laser beam while shifting an irradiation position thereof, prior to the insert molding step, to form the terminal nano-pillars standing in a forest on the terminal seal portion, The insert molding process includes: The resin member is molded while filling the spaces between the terminal nano-pillars of the terminal seal portion. A method for manufacturing an electricity storage device.

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