Power storage device and method for manufacturing power storage device

Abstract

The invention provides an electricity storage device and a method for manufacturing the electricity storage device. Even if the electricity storage device is placed at a low temperature of-40 DEG C, cracks do not easily occur in the vicinity of a pair of long-side-side joint surfaces in a resin inner side part of a resin member. A power storage device includes a case cover member, a terminal member, and a resin member. The resin member has a resin outer portion, a resin inner portion, and a resin hole interior, and the housing cover member and the resin member are configured such that when the housing cover member and the resin member are placed in an environment at a temperature of-40 DEG C, the resin member is warped in a convex shape toward the outside in the thickness direction of the cover in the longitudinal direction of the cover, and the resin member is warped toward the outside in the thickness direction of the cover in the longitudinal direction of the cover. A pair of long-side joining surfaces in the resin inner portion press the terminal members in the cover long-side direction, respectively.

Description

Technical Field

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

[0002] As a power storage device, there is known a battery in which positive and negative terminal members are fixed to a rectangular plate-shaped housing cover member constituting a rectangular box-shaped housing via a resin member. Specifically, the positive and negative terminal members are respectively inserted into insertion holes provided in the housing cover member and extend from the inside of the housing to the outside, and the resin member insulates the housing cover member from the terminal member and is airtightly joined to them to fix the terminal member to the housing cover member. Such a battery is disclosed, for example, in Patent Document 1.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2022-079172

[0006] In the above-mentioned battery, when the battery is placed in an extremely low temperature environment such as -40°C, cracks (crazing) along the boundary are sometimes generated in the resin member near the boundary with the terminal member due to cohesive failure. Specifically, the resin member has: a resin outer portion, the resin outer portion is located on the outside of the cover thickness direction of the shell cover member; a resin inner portion, the resin inner portion is located on the inside of the cover thickness direction of the shell cover member; and a resin hole interior, the resin hole interior is located in the insertion hole of the shell cover member and is integrally connected to the resin outer portion and the resin inner portion. Moreover, the joint surface of the resin inner portion that is joined to the terminal member has a pair of long side joint surfaces facing the long side direction of the cover and a pair of short side joint surfaces facing the short side direction of the cover. Moreover, it can be seen that the above-mentioned cracks may be generated near the pair of long side joint surfaces in the resin inner portion.

[0007] The reason is that when the battery is left at a low temperature such as -40°C, the resin member will be warped in a convex shape in the direction of the cover thickness in the long side direction of the cover (hereinafter, simply referred to as "inward convex warping"). It is believed that when such inward convex warping occurs in the resin member, the inner side of the resin deforms in a direction away from the terminal member in the long side direction of the cover, and cohesive failure occurs near the pair of long side joint surfaces to form cracks. Summary of the invention

[0008] Problems to be solved by the invention

[0009] The present invention has been made in view of the above-mentioned current situation and provides an electric storage device and a method for manufacturing the electric storage device in which cracks are unlikely to occur near a pair of long-side joint surfaces in the resin inner portion of a resin member even when the electric storage device is left at a low temperature of -40°C.

[0010] Means for solving problems

[0011] (1) One embodiment of the present invention for solving the above-mentioned problems is an electrical storage device, the electrical storage device comprising: a case cover member having an insertion hole and extending in the cover longitudinal direction; a terminal member, the terminal member being inserted into the insertion hole of the case cover member; and a resin member, the resin member insulating the case cover member from the terminal member and being airtightly joined to the case cover member and the terminal member to fix the terminal member to the case cover member, the resin member comprising: a resin outer portion, the resin outer portion being located on the outside of the case cover member in the cover thickness direction; a resin inner portion, the resin inner portion being located on the inside of the case cover member in the cover thickness direction; and an interior of the resin hole, the resin inner portion being located on the inside of the case cover member in the cover thickness direction. The interior of the resin hole is located in the insertion hole of the shell cover component and is integrally connected to the resin outer part and the resin inner part. The terminal component passes through the resin outer part, the interior of the resin hole and the resin inner part and extends inward in the thickness direction of the cover. The resin inner part of the resin component includes a pair of long side joint surfaces facing the long side direction of the cover and joined to the terminal component. The shell cover component and the resin component are configured so that when the power storage device is placed in a temperature environment of -40°C, the resin component is warped in a convex shape in the long side direction of the cover toward the outside in the thickness direction of the cover, and the pair of long side joint surfaces in the resin inner part press the terminal component in the long side direction of the cover respectively.

[0012] In the above-mentioned power storage device, when the power storage device is placed at a low temperature of -40°C, contrary to the above, the resin member produces a convex warp in the long side direction of the cover toward the outside in the thickness direction of the cover (hereinafter also referred to as "convex warp toward the outside"). And, as a result, a pair of long side joint surfaces in the resin inner part press the terminal member in the long side direction of the cover respectively. Therefore, it is possible to suppress the cohesive failure and crack formation near the pair of long side joint surfaces in the resin inner part. Therefore, for the above-mentioned power storage device, even if the power storage device is placed at a low temperature of -40°C, it is not easy to produce cracks near the pair of long side joint surfaces in the resin inner part of the resin member.

[0013] 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.

[0014] (2) According to the electric storage device described in (1), in the resin member, a volume V1 of the resin outer side portion may be larger than a volume V2 of the resin inner side portion (V1>V2).

[0015] When the volume V2 of the resin inner portion is larger than the volume V1 of the resin outer portion of the resin member (V1 < V2), when the electrical storage device is placed at a low temperature of -40°C, the resin member is likely to be warped in a convex shape toward the inside as described above. In contrast, in the electrical storage device described above, since the volume V1 of the resin outer portion of the resin member is larger than the volume V2 of the resin inner portion (V1 > V2), it is possible to easily configure an electrical storage device in which the resin member is warped in a convex shape toward the outside at a low temperature of -40°C.

[0016] (3) According to the storage device described in (1) or (2), the terminal sealing portion of the terminal member that is airtightly joined to the resin member has terminal nanocolumns with a height of more than 50 nm on its surface, and the terminal nanocolumns are formed by beads of particles with a diameter of less than 100 nm from the metal constituting the terminal member. The resin member is filled with a resin material constituting the resin member between the terminal nanocolumns and is airtightly joined to the terminal sealing portion.

[0017] In the above-mentioned power storage device, the above-mentioned terminal nanocolumns are arranged on the surface of the terminal sealing part of the terminal member, and the terminal nanocolumns are filled with resin material, and the resin member and the terminal sealing part are airtightly joined. Thus, the bonding strength between the terminal sealing part of the terminal member and the resin member can be improved, and the sealing performance of the terminal member and the resin member can be well maintained.

[0018] It should be noted that, as the “particles derived from the metal constituting the terminal member” constituting the terminal nanocolumn, for example, particles consisting of the above-mentioned metal, particles consisting of the above-mentioned metal oxide, particles consisting of the above-mentioned metal and the above-mentioned metal oxide can be listed. In addition, particles consisting of the above-mentioned metal, the above-mentioned metal oxide and the above-mentioned metal nitride, etc., particles containing the above-mentioned metal nitride, etc. can also be listed.

[0019] The “terminal sealing 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 portion of the terminal joint portion.

[0020] (4) In addition, another embodiment is a method for manufacturing an electrical storage device, the electrical storage device comprising: a case cover member, the case cover member having an insertion hole and extending in the direction of the long side of the cover; a terminal member, the terminal member being inserted into the insertion hole of the case cover member; and a resin member, the resin member insulating the case cover member from the terminal member and being airtightly bonded to the case cover member and the terminal member to fix the terminal member to the case cover member, the resin member comprising: a resin outer portion, the resin outer portion being located on the outside of the case cover member in the cover thickness direction; a resin inner portion, the resin inner portion being located on the inside of the case cover member in the cover thickness direction; and a resin hole interior, the resin hole interior being located in the insertion hole of the case cover member and being bonded to the resin outer portion and The resin inner side portion is connected integrally, the terminal member passes through the resin outer side portion, the inside of the resin hole and the resin inner side portion and extends inward in the thickness direction of the cover, the resin inner side portion of the resin member includes a pair of long side joint surfaces facing the long side direction of the cover and joined to the terminal member, the shell cover member and the resin member are configured so that when the power storage device is placed in a temperature environment of -40°C, the resin member is warped in a convex shape in the long side direction of the cover toward the outside in the thickness direction of the cover, and the pair of long side joint surfaces in the resin inner side portion press the terminal member in the long side direction of the cover respectively, and the manufacturing method of the power storage device includes an insert molding process for insert molding the resin member in a state where the terminal member is inserted into the insertion hole of the shell cover member.

[0021] In the above-mentioned method for manufacturing an electric storage device, since the resin member is insert-molded in the insert-molding step, an electric storage device in which the resin member is warped in the convex shape described above at a low temperature of -40°C can be easily manufactured.

[0022] (5) According to the method for manufacturing an electric storage device described in (4), in the insert molding step, the resin member may be molded so that a volume V1 of the resin outer portion is larger than a volume V2 of the resin inner portion (V1>V2).

[0023] In the above method for manufacturing an electric storage device, since the resin member is formed such that the volume V1 of the resin outer portion is larger than the volume V2 of the resin inner portion, an electric storage device in which the resin member warps outward in the above-mentioned convex shape at a low temperature of -40°C can be easily manufactured.

[0024] (6) According to the method for manufacturing an electrical storage device described in (4) or (5), the terminal sealing portion of the terminal member that is airtightly joined to the resin member may have terminal nanocolumns with a height of more than 50 nm standing on its surface, the terminal nanocolumns being formed by particles of a metal constituting the terminal member and having a diameter of less than 100 nm connected in a beaded manner to form a columnar shape, the resin member is filled with a resin material constituting the resin member between the terminal nanocolumns that are standing in a row and is airtightly joined to the terminal sealing portion, and before the insert molding step, the method for manufacturing an electrical storage device may further include a terminal nanocolumn forming step, in which a pulsed oscillating laser is irradiated onto the terminal sealing portion of the terminal member while staggering the irradiation position to form a row of terminal nanocolumns in the terminal sealing portion, and in the insert molding step, the resin member is molded while the resin material is filled between the terminal nanocolumns that are standing in a row in the terminal sealing portion.

[0025] In the method for manufacturing the power storage device, in the terminal nanocolumn forming step, the terminal nanocolumn is formed on the surface of the terminal sealing portion by irradiating the laser as described above, so that the terminal nanocolumn can be easily formed on the terminal sealing portion. In addition, in the insert molding step, the resin member is molded while the resin material is filled between the terminal nanocolumns, so that the bonding strength between the terminal sealing portion of the terminal member and the resin member can be improved, and the sealing performance between the terminal member and the resin member can be well maintained. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a perspective view of a battery according to an embodiment.

[0027] Figure 2 It is a partially cut-away cross-sectional view of the battery according to the embodiment along the battery height direction and the battery width direction.

[0028] Figure 3A It is a partially enlarged plan view of the vicinity of the resin member that fixes the terminal member to the case cover member according to the embodiment, and is a partially enlarged plan view viewed from the outside in the cover thickness direction.

[0029] Figure 3B It is a partially enlarged plan view of the vicinity of the resin member that fixes the terminal member to the case cover member according to the embodiment, and is a partially enlarged plan view viewed from the inner side in the cover thickness direction.

[0030] Figure 4A This is a partial enlarged cross-sectional view of the resin member near the terminal member fixed to the housing cover member of the embodiment, and is taken along the cover long side direction and the cover thickness direction. Figure 3A The sectional view as viewed in the direction of 4A-4A.

[0031] Figure 4B This is a partial enlarged cross-sectional view of the resin member near the terminal member fixed to the housing cover member of the embodiment, and is taken along the short side direction of the cover and the cover thickness direction. Figure 3A The 4B-4B section view in FIG.

[0032] Figure 5 It is a partially enlarged cross-sectional view showing terminal nano-columns (lid nano-columns) standing in a forest on the surface of a terminal sealing portion (lid sealing portion) according to an embodiment.

[0033] Fig. 6A is an explanatory diagram showing the state of the resin member and the like when the battery of the embodiment is placed at a low temperature of -40°C, and is Figure 4A The explanatory diagram corresponding to the sectional view.

[0034] Figure 6B is an explanatory diagram showing the state of the resin member and the like when the battery of the embodiment is placed at a low temperature of -40°C, and is Figure 3B The explanatory diagram corresponding to the plan view.

[0035] Figure 7 This is a flowchart of a method for manufacturing a battery according to an embodiment.

[0036] Figure 8 It is an explanatory diagram showing a terminal nanocolumn forming step (cap nanocolumn forming step) of the battery manufacturing method according to the embodiment.

[0037] Fig.9A It is an explanatory diagram of an insert molding step of the battery manufacturing method according to the embodiment, and shows a state where a terminal member is inserted into an insertion hole of a case cover member.

[0038] Fig. 9B It is an explanatory diagram of an insert molding step in the method for manufacturing a battery according to the embodiment, and shows a state in which a resin member is molded.

[0039] Fig. 10A is an explanatory diagram showing the state of the resin member when the battery of the comparative method is placed at a low temperature of -40°C, and is Fig. 6A Corresponding illustration.

[0040] Fig. 10B is an explanatory diagram showing the state of the resin member when the battery of the comparative method is placed at a low temperature of -40°C, and is Figure 6B Corresponding illustration.

[0041] Description of Reference Numerals

[0042] 1Battery (electricity storage device)

[0043] 10 Housing

[0044] 30 Housing cover member

[0045] 30h1, 30h2 through hole

[0046] 40 Electrode body

[0047] 50, 60 terminal components

[0048] 55, 65 Terminal sealing part

[0049] 55m, 65m (surface of terminal seal)

[0050] 57, 67 terminal nanopillars

[0051] 57p, 67p particles

[0052] 70, 80 resin components

[0053] 71, 81 resin outer part

[0054] 72, 82 resin hole interior

[0055] 73, 83 resin inner part

[0056] 73ma, 83ma long side joint surface

[0057] 73mb, 83mb short side joint surface

[0058] DH cover long side direction

[0059] EH cover short side direction

[0060] FH Cover thickness direction

[0061] FH1 (cover thickness direction) outer side

[0062] FH2 (cover thickness direction) inner side

[0063] V1 (volume outside the resin)

[0064] V2 (volume inside the resin)

[0065] WA (warping in the direction of the cover's long side that is convex toward the outside in the cover's thickness direction)

[0066] WB (warping in the direction of the cap thickness in the direction of the cap length)

[0067] KR Crack

[0068] LC Laser

[0069] S1 Terminal Nanocolumn Formation Process

[0070] S3 Insert Molding Process DETAILED DESCRIPTION

[0071] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Figure 1 A perspective view showing a battery (electricity storage device) 1 according to this embodiment, Figure 2 FIG. 2 is a partially cutaway cross-sectional view of the battery 1. In addition, in the vicinity of the resin members 70 and 80 that fix the terminal members 50 and 60 to the case cover member 30, Figure 3A and Figure 3B A partial enlarged plan view is shown in Figure 4A and Figure 4B A partial enlarged cross-sectional view is shown in FIG. Figure 5 FIG. 2 shows a partially enlarged cross-sectional view of the terminal nanopillars 57, 67 and the like standing on the surfaces 55m, 65m of the terminal sealing portions 55, 65. It should be noted that, hereinafter, the battery height direction AH, the battery width direction BH, the battery thickness direction CH of the battery 1 and the cover long side direction DH, the cover short side direction EH, and the cover thickness direction FH of the housing cover member 30 are defined as Figure 1 to Figure 4B The directions shown are used for illustration.

[0072] The battery 1 is a square (rectangular) and sealed lithium ion secondary battery mounted on hybrid vehicles, plug-in hybrid vehicles, electric vehicles and the like. The battery 1 is composed of a housing 10, an electrode body 40 housed in the housing 10, a positive terminal member 50 fixed to the housing 10 via a resin member 70, and a negative terminal member 60 fixed to the housing 10 via a resin member 80. The electrode body 40 is covered by a bag-shaped insulating retainer 7 composed of an insulating film in the housing 10. In addition, an electrolyte 5 is contained in the housing 10, a part of which is impregnated in the electrode body 40, and the remaining part is accumulated on the bottom wall of the housing 10.

[0073] The case 10 is a rectangular box made of metal (aluminum in this embodiment), and is composed of a case body member 20 having a bottomed square tube shape with a rectangular opening 20c and accommodating an electrode body 40 therein, and a case cover member 30 having a rectangular plate shape 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 cover member 30 are welded airtightly over the entire circumference.

[0074] The housing cover member 30 of the housing 10 is provided with a safety valve 11, which breaks and opens the valve when the internal pressure of the housing 10 exceeds the valve opening pressure. In addition, the housing cover member 30 is provided with a liquid injection hole 30k that penetrates the housing cover member 30 in the cover thickness direction FH, and the liquid injection hole 30k is hermetically sealed by a disk-shaped sealing member 12 made of aluminum.

[0075] The electrode body 40 accommodated in the housing 10 is a rectangular parallelepiped and stacked type, and is formed by alternately stacking a plurality of positive electrode plates 41 and a plurality of negative electrode plates 42 in the battery thickness direction CH via a separator 43 composed of a porous film made of resin. The positive electrode plate 41, the negative electrode plate 42 and the separator 43 are each rectangular in shape extending in the battery height direction AH and the battery width direction BH.

[0076] The positive electrode plate 41 is composed of a positive electrode collector foil and a positive electrode active material layer, wherein the positive electrode collector foil is composed of aluminum foil, and the positive electrode active material layer is formed on both main surfaces of the positive electrode collector foil and contains positive electrode active material particles. A portion of the positive electrode collector foil is formed into a positive electrode foil exposed portion extending to one side BH1 of the battery width direction BH and exposed without the positive electrode active material layer on its two main surfaces. In addition, the positive electrode foil exposed portions of each positive electrode plate 41 overlap in the foil thickness direction to form a positive electrode collector portion 40c. The positive electrode collector portion 40c is electrically connected to a terminal member 50 of the positive electrode described later.

[0077] In addition, the negative electrode plate 42 is composed of a negative electrode collector foil and a negative electrode active material layer, wherein the negative electrode collector foil is composed of a copper foil, and the negative electrode active material layer is formed on both main surfaces of the negative electrode collector foil and contains negative electrode active material particles. A portion of the negative electrode collector foil is formed into a negative electrode foil exposure portion that extends to the other side BH2 of the battery width direction BH and is exposed without the negative electrode active material layer on its two main surfaces. In addition, the negative electrode foil exposure portions of each negative electrode plate 42 overlap in the foil thickness direction to form a negative electrode collector portion 40d. The negative electrode collector portion 40d is electrically connected to the terminal member 60 of the negative electrode described later.

[0078] In the vicinity of the end portions of one side DH1 and the other side DH2 in the cover longitudinal direction DH (one side BH1 and the other side BH2 in the battery width direction BH) of the case cover member 30, rectangular insertion holes 30h1 and 30h2 are provided respectively, which penetrate the case cover member 30 in the cover thickness direction FH. A positive electrode terminal member 50 made of aluminum is inserted into the insertion hole 30h1 on one side, and the terminal member 50 is fixed to the case cover member 30 in a state of being insulated from the case cover member 30 via the resin member 70. In addition, a negative electrode terminal member 60 made of copper is inserted into the insertion hole 30h2 on the other side, and the terminal member 60 is fixed to the case cover member 30 in a state of being insulated from the case cover member 30 via the resin member 80.

[0079] First, the resin members 70 and 80 are described. The resin members 70 and 80 insulate the housing cover member 30 and the terminal members 50 and 60, and are bonded to the housing cover member 30 and the terminal members 50 and 60 to fix the terminal members 50 and 60 to the housing cover member 30. Specifically, the resin members 70 and 80 are filled with a resin material 75 between the terminal nanopillars 57 and 67 of the terminal sealing parts 55 and 65 described later in the terminal members 50 and 60, and are airtightly bonded to the terminal sealing parts 55 and 65 (see Figure 5 In addition, the resin members 70 and 80 are filled with a resin material 75 between the forested cover nano-columns 37 of the cover sealing portions 31 and 32 described later in the case cover member 30 , and are airtightly bonded to the cover sealing portions 31 and 32 .

[0080] The resin members 70 and 80 are composed of resin outer parts 71 and 81, resin inner parts 73 and 83, and resin hole inner parts 72 and 82 located between the resin outer parts 71 and 81 and the resin inner parts 73 and 83 and connected to the resin outer parts 71 and 81 and the resin inner parts 73 and 83 (integrally formed). The resin outer parts 71 and 81 are located on the outer side FH1 of the cover thickness direction FH of the case cover member 30 (the upper side AH1 of the battery height direction AH). In addition, the resin inner parts 73 and 83 are located on the inner side FH2 of the cover thickness direction FH of the case cover member 30 (the lower side AH2 of the battery height direction AH). The resin inner parts 73 and 83 have a pair of long side joint surfaces 73ma and 83ma facing the cover long side direction DH (battery width direction BH) (that is, the surface normal line coincides with the cover long side direction DH) and joined to the terminal members 50 and 60. In addition, the resin inner part 73, 83 has a pair of short side joint surfaces 73mb, 83mb facing the cover short side direction EH (battery thickness direction CH) (that is, the surface normal line coincides with the cover short side direction EH) and joined to the terminal members 50, 60. In addition, the resin hole interior 72, 82 is a portion located in the hole of the insertion hole 30h1, 30h2 of the case cover member 30. In the present embodiment, the volume V1 of the resin outer part 71, 81 is larger than the volume V2 of the resin inner part 73, 83 (V1>V2). Specifically, the volume V1 of the resin outer part 71, 81 is about 1.5 times the volume V2 of the resin inner part 73, 83.

[0081] The resin members 70 and 80 are composed of a resin material 75 including a thermoplastic main resin, a thermoplastic elastomer, and a filler. In the present embodiment, the main resin is polyphenylene sulfide (PPS), the elastomer is a thermoplastic polyurethane elastomer, and the filler is a fibrous (approximately 10 μm in diameter × 300 μm in length) glass filler. In addition, the linear expansion coefficient α1 of the resin material 75 in the temperature range of -40 to 65°C is α1 = 2.0 × 10 -5(1 / K). As described above, the housing cover member 30 is made of aluminum, and its linear expansion coefficient α2 in the temperature range of -40 to 65°C is α2=2.4×10 -5 (1 / K), therefore, the linear expansion coefficient α2 of the metal (aluminum) constituting the case cover member 30 is larger than the linear expansion coefficient α1 of the resin material 75 constituting the resin members 70 , 80 .

[0082] Next, the terminal components 50 and 60 are described. The terminal components 50 and 60 are components formed by stamping a metal plate (a positive electrode is an aluminum plate, and a negative electrode is a copper plate). The terminal components 50 and 60 penetrate the resin outer portion 71 and 81 of the resin components 70 and 80, the resin hole inner portion 72 and 82, and the resin inner portion 73 and 83 and extend to the inner side FH2 (lower side AH2) in the cover thickness direction FH. The terminal components 50 and 60 are composed of the terminal outer portion 51 and 61, the terminal hole inner portion 52 and 62, the terminal inner portion 53 and 63, and the terminal extension portion 54 and 64.

[0083] The terminal outer portion 51, 61 is a portion located on the outer side FH1 of the cover thickness direction FH of the case cover member 30 and joined to the resin outer portions 71, 81 of the resin members 70, 80. The terminal outer portion 51, 61 is composed of a rectangular plate-shaped top plate portion 51p, 61p extending in the cover long side direction DH and the cover short side direction EH, and an extension portion 51q, 61q that is bent at the end of the top plate portion 51p, 61p on one side EH1 in the cover short side direction EH (one side CH1 in the battery thickness direction CH) and extends to the inner side FH2 in the cover thickness direction FH.

[0084] The terminal hole inner portions 52 and 62 are located inside the insertion holes 30 h 1 and 30 h 2 of the case cover member 30 and are joined to the resin hole inner portions 72 and 82 of the resin members 70 and 80 .

[0085] The terminal inner side portion 53, 63 is a portion located on the inner side FH2 of the cover thickness direction FH of the housing cover member 30 and joined to the resin inner side portion 73, 83 of the resin member 70, 80. Specifically, in the terminal inner side portion 53, 63, a pair of long side joining surfaces 73ma, 83ma of the resin inner side portion 73, 83 are joined in the cover long side direction DH, and a pair of short side joining surfaces 73mb, 83mb of the resin inner side portion 73, 83 are joined in the cover short side direction EH.

[0086] The terminal extensions 54 and 64 are portions extending from the terminal inner portions 53 and 63 further toward the lower side AH2 and protruding from the resin members 70 and 80 toward the lower side AH2. The positive terminal extension 54 is welded to the positive electrode collector 40c of the electrode body 40 at the top end of the lower side AH2, and is electrically connected to the positive electrode collector 40c. In addition, the negative terminal extension 64 is welded to the negative electrode collector 40d of the electrode body 40 at the top end of the lower side AH2, and is electrically connected to the negative electrode collector 40d.

[0087] In the present embodiment, the extensions 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 the terminal sealing portions 55, 65 airtightly joined to the resin members 70, 80. Figure 5 As shown, terminal nanocolumns 57, 67 are arranged on the surfaces 55m, 65m of the terminal sealing portions 55, 65 (the surfaces of the extension portions 51q, 61q of the terminal outer portions 51, 61, the surfaces of the insides 52, 62 of the terminal holes, and the surfaces of the terminal inner portions 53, 63). The terminal nanocolumns 57, 67 are formed by particles 57p, 67p from the metals (aluminum for the positive electrode and copper for the negative electrode) constituting the terminal members 50, 60, which are connected in a beaded manner to form columns.

[0088] Specifically, the positive terminal nanocolumn 57 is composed of particles 57p formed of aluminum and aluminum oxide, and the negative terminal nanocolumn 67 is composed of particles 67p formed of copper and copper oxide. The diameter Da of the particles 57p and 67p is less than 100nm (approximately Da=30nm in this embodiment), and the height ha of the terminal nanocolumns 57 and 67 is greater than 50nm, and further greater than 300nm (approximately ha=500nm in this embodiment). The resin members 70 and 80 are filled with resin material 75 between these terminal nanocolumns 57 and 67, and are airtightly bonded to the terminal sealing parts 55 and 65.

[0089] In addition, the cover seal portions 31 and 32 (see Figure 4A and Figure 4B ), and the resin members 70, 80 are joined airtightly. Specifically, the cover seals 31, 32 have rectangular annular outer side surfaces 31m, 32m facing the outer side FH1 (upper side AH1) of the cover thickness direction FH and rectangular annular inner side surfaces 31n, 32n facing the inner side FH2 (lower side AH2) of the cover thickness direction FH. On these surfaces, similarly to the surface 55m of the positive terminal seal 55 (refer to Figure 5), there are a forest of particles 37p formed of aluminum and aluminum oxide connected in a beaded manner to form a columnar cap nanocolumn 37. The diameter Da of the particle 37p is less than 100nm (approximately Da=30nm in this embodiment), and the height ha of the cap nanocolumn 37 is greater than 50nm, and further greater than 300nm (approximately ha=500nm in this embodiment). The resin members 70 and 80 are filled with resin material 75 between these forested cap nanocolumns 37, and are airtightly bonded to the cap sealing parts 31 and 32.

[0090] In the battery 1 of this embodiment, the case cover member 30 and the resin members 70 and 80 are configured as follows. That is, when the battery 1 is placed in a temperature environment of -40°C (see Fig. 6A and Figure 6B ), a convex warp WA is generated in the resin members 70 and 80 in the cover longitudinal direction DH toward the outer side FH1 in the cover thickness direction FH. As a result, a pair of long side joint surfaces 73ma and 83ma in the resin inner side portions 73 and 83 of the resin members 70 and 80 are respectively configured to press the terminal members 50 and 60 in the cover longitudinal direction DH.

[0091] The reason why the resin members 70 and 80 are warped in a convex shape toward the outside FH1 is considered to be as follows. That is, in the present embodiment, as described above, the linear expansion coefficient α2 of the metal (aluminum) constituting the housing cover member 30 is larger than the linear expansion coefficient α1 of the resin material 75 constituting the resin members 70 and 80. Therefore, when the battery 1 is placed at a low temperature of -40°C, the housing cover member 30 shrinks significantly in the cover long side direction DH compared to the resin members 70 and 80. On the other hand, since the resin members 70 and 80 are bonded to the housing cover member 30, the resin members 70 and 80 and the housing cover member 30 are bent and deformed in a bimetallic manner due to the difference in thermal contraction. It is considered that since the volume V1 of the resin outer portions 71 and 81 of the resin members 70 and 80 is larger than the volume V2 of the resin inner portions 73 and 83 , the influence of the resin outer portions 71 and 81 is greater than that of the resin inner portions 73 and 83 , and the resin members 70 and 80 and the case cover member 30 are warped WA in a convex shape toward the outer side FH1 .

[0092] Here, the structures of the case cover member 930 and the resin members 970 and 980 in the battery of the comparative embodiment will be described (see Fig. 10A and Fig. 10B). When the comparative battery is placed in a temperature environment of -40°C, in contrast to the battery 1 of the present embodiment, the resin members 970 and 980 are subjected to warpage WB in a convex shape toward the inner side FH2 (lower side AH2) in the cover thickness direction FH in the cover long side direction DH. When such a convex warpage WB toward the inner side FH2 is generated in the resin members 970 and 980, the resin inner side portions 973 and 983 are deformed in a direction away from the terminal members 950 and 960 in the cover long side direction DH, and cohesive failure occurs near a pair of long side joint surfaces 973ma and 983ma, respectively, to form cracks KR.

[0093] In contrast, in the battery 1 of the present embodiment, as described above, the warp WA in a convex shape toward the outer side FH1 is generated in the resin members 70 and 80 at a low temperature of -40°C. In addition, the pair of long side joint surfaces 73ma and 83ma in the resin inner side parts 73 and 83 of the resin members 70 and 80 press the terminal members 50 and 60 in the cover long side direction DH, respectively. Therefore, it is possible to suppress the cohesive failure and the formation of cracks KR in the vicinity of the pair of long side joint surfaces 73ma and 83ma in the resin inner side parts 73 and 83. Therefore, for the battery 1, even if the battery 1 is placed at a low temperature of -40°C, it is not easy for cracks KR to be generated in the vicinity of the pair of long side joint surfaces 73ma and 83ma in the resin inner side parts 73 and 83 of the resin members 70 and 80.

[0094] Moreover, in the present embodiment, since the volume V1 of the resin outer portions 71 and 81 of the resin members 70 and 80 is made larger than the volume V2 of the resin inner portions 73 and 83 (V1>V2), it is possible to easily construct a battery 1 in which the resin members 70 and 80 produce a warp WA in a convex shape toward the outside FH1 at a low temperature of -40°C.

[0095] In addition, in the present embodiment, terminal nanopillars 57 and 67 are arranged on the surfaces 55m and 65m of the terminal sealing parts 55 and 65 of the terminal members 50 and 60, and resin materials 75 are filled between these terminal nanopillars 57 and 67, and the resin members 70 and 80 are airtightly bonded to the terminal sealing parts 55 and 65. Thus, the bonding strength between the terminal sealing parts 55 and 65 of the terminal members 50 and 60 and the resin members 70 and 80 can be improved, and the sealing properties between the terminal members 50 and 60 and the resin members 70 and 80 can be well maintained.

[0096] Next, a method for manufacturing the battery 1 is described (see Figures 7 to 9B). First, prepare the shell cover member 30Z before roughening in advance. The shell cover member 30Z before roughening is obtained by punching an aluminum plate into a predetermined shape and forming a liquid injection hole 30k, insertion holes 30h1, 30h2 and a safety valve 11 thereon. In addition, prepare the terminal members 50Z and 60Z before roughening in advance. The terminal member 50Z of the positive electrode before roughening is obtained by punching an aluminum plate into a predetermined shape and performing a buckling process. In addition, the terminal member 60Z of the negative electrode before roughening is obtained by punching a copper plate into a predetermined shape and performing a buckling process.

[0097] Furthermore, in the "terminal nanocolumn forming step S1" (refer to Figure 7 ), while shifting the irradiation position, the terminal sealing portions 55 and 65 in the terminal members 50Z and 60Z are irradiated with pulsed laser light LC (see Figure 8 ), a forest of terminal nanopillars 57, 67 are formed on the surfaces 55m, 65m of the terminal sealing portions 55, 65. As described above (see also Figure 5 ), the terminal nanocolumns 57, 67 are formed into columns by particles 57p, 67p being connected in a beaded manner.

[0098] In the present embodiment, regarding the irradiation conditions of the positive laser, the wavelength is set to 1064nm, the peak output is set to 5kW, the pulse width is set to 150ns, the pitch pb is set to 75μm, and the spot diameter Db is set to 80μm. In addition, regarding the irradiation conditions of the negative laser, the wavelength is set to 1064nm, the peak output is set to 20kW, the pulse width is set to 50ns, the pitch pb is set to 60μm, and the spot diameter Db is set to 75μm. At the circular portion of the terminal sealing portion 55, 65 irradiated with the laser LC in the top view, the metal (aluminum at the positive electrode and copper at the negative electrode) constituting the vicinity of the surface 55m, 65m melts and then becomes vapor. Thereafter, when the temperature of the vapor decreases, it becomes particles 57p, 67p (particles 57p of aluminum and aluminum oxide at the positive electrode and particles 67p of copper and copper oxide at the negative electrode), which are deposited on the surfaces 55m, 65m of the terminal sealing portion 55, 65. By irradiating the terminal sealing portions 55 and 65 with the laser beam LC while shifting the irradiation position, the particles 57 p and 67 p are accumulated in a bead-like manner and connected to form a columnar shape, thereby forming a forest of terminal nanocolumns 57 and 67 .

[0099] In addition, in another "cap nanocolumn forming step S2" (refer to Figure 7 ), while shifting the irradiation position, the cover sealing portions 31 and 32 in the housing cover member 30Z are irradiated with pulsed laser light LC (see Figure 8 ), a forest of cover nanorods 37 are formed on the outer side surfaces 31m, 32m and the inner side surfaces 31n, 32n of the cover sealing portions 31, 32, respectively. As described above (see also Figure 5), the cap nanocolumn 37 is formed by particles 37p formed of aluminum and aluminum oxide being connected in a beaded manner to form a columnar shape. In this embodiment, the laser irradiation conditions are the same as the laser irradiation conditions when the terminal nanocolumn 57 is formed in the terminal sealing portion 55 of the positive electrode in the terminal nanocolumn forming step S1.

[0100] Next, in the "insert molding step S3" (refer to Figure 7 ), while the terminal members 50 and 60 are inserted into the insertion holes 30h1 and 30h2 of the housing cover member 30, the resin members 70 and 80 are insert-molded using the aforementioned resin material 75 (see Fig.9A as well as Fig. 9B ). Specifically, the insert molding step S3 is performed using a molding die (not shown) having an upper die and a lower die. First, the housing cover member 30 is arranged at a predetermined position of the lower die, and then the terminal members 50 and 60 are inserted into the insertion holes 30h1 and 30h2 of the housing cover member 30 (see Fig.9A ). Thereafter, the upper mold is moved toward the lower mold to close the forming mold.

[0101] Next, the molten resin material 75 is injected into the mold cavity of the molding die. At this time, the resin material 75 is also filled between the terminal nano-pillars 57 and 67 of the terminal sealing parts 55 and 65, and between the cover nano-pillars 37 of the cover sealing parts 31 and 32, forming the resin members 70 and 80 that are airtightly bonded to the terminal sealing parts 55 and 65 and the cover sealing parts 31 and 32 (see Fig. 9B ). By forming the cavity of the molding die into a shape in which the volume V1 of the resin outer portion 71, 81 is larger than the volume V2 of the resin inner portion 73, 83, the resin members 70, 80 are molded in such a manner that the volume V1 of the resin outer portion 71, 81 is larger than the volume V2 of the resin inner portion 73, 83. Thereafter, the cover assembly 15 in which the terminal members 50, 60 are fixed to the housing cover member 30 via the resin members 70, 80 is removed from the molding die.

[0102] Next, in the "electrode body connection step S4" (see Figure 7 ), an electrode body 40 obtained by stacking a positive electrode plate 41, a negative electrode plate 42, and a separator 43 is prepared, and the terminal extension 54 of the positive terminal member 50 in the above-mentioned cap assembly 15 is welded to the positive electrode collector 40c of the electrode body 40. In addition, the terminal extension 64 of the negative terminal member 60 in the cap assembly 15 is welded to the negative electrode collector 40d of the electrode body 40. Thereafter, the electrode body 40 is covered with a bag-shaped insulating retainer 7.

[0103] Next, in the "electrode body housing / casing forming step S5", the case body member 20 is prepared, the electrode body 40 covered by the above-mentioned insulating holder 7 is inserted into the case body member 20, and the opening 20c of the case body member 20 is blocked by the case cover member 30. Then, the opening 20c of the case body member 20 and the peripheral edge 30f of the case cover member 30 are airtightly laser welded throughout the entire circumference to form the case 10 in which the electrode body 40 is housed.

[0104] Next, in the "liquid injection / sealing step S6", the electrolyte 5 is injected into the case 10 through the liquid injection hole 30k, and the electrolyte 5 is impregnated into the electrode body 40. Thereafter, the liquid injection hole 30k is covered from the outside with the sealing member 12, and the sealing member 12 is laser welded to the case 10 in an airtight manner.

[0105] Next, in the "initial charge / aging step S7", the battery 1 is connected to a charging device (not shown) to perform initial charge on the battery 1. Thereafter, the initially charged battery 1 is left to stand for a predetermined time to perform aging on the battery 1. In this way, the battery 1 is completed.

[0106] As described above, in the method for manufacturing the battery 1 , the resin members 70 , 80 are insert-molded in the insert-molding step S3 . Therefore, the battery 1 in which the resin members 70 , 80 are warped WA in a convex shape toward the outer side FH1 at a low temperature of −40° C. can be easily manufactured.

[0107] Moreover, in the present embodiment, since the resin members 70 and 80 are formed so that the volume V1 of the resin outer portions 71 and 81 is larger than the volume V2 of the resin inner portions 73 and 83, it is possible to easily manufacture a battery 1 in which the resin members 70 and 80 are warped WA in a convex shape toward the outer side FH1 at a low temperature of -40°C.

[0108] In addition, in the terminal nanocolumn forming step S1, the laser LC is irradiated to form the terminal nanocolumns 57 and 67 on the surfaces 55m and 65m of the terminal sealing parts 55 and 65, so that the terminal nanocolumns 57 and 67 can be easily formed in the terminal sealing parts 55 and 65. In addition, in the insert molding step S3, the resin members 70 and 80 are molded while the resin material 75 is filled between the terminal nanocolumns 57 and 67, so that the bonding strength between the terminal sealing parts 55 and 65 of the terminal members 50 and 60 and the resin members 70 and 80 can be improved, and the sealing performance between the terminal members 50 and 60 and the resin members 70 and 80 can be well maintained.

[0109] As mentioned above, although this invention was demonstrated based on embodiment, this invention is not limited to embodiment, It is a matter of course that it can be applied with appropriate changes within the range which does not deviate from the summary.

Claims

1. An electric storage device, comprising: a housing cover member having an insertion hole and extending along the long side direction of the cover; a terminal member inserted into the insertion hole of the housing cover member; and a resin member that insulates the case cover member from the terminal member and is airtightly bonded to the case cover member and the terminal member to fix the terminal member to the case cover member, wherein: The resin member has: a resin outer portion, the resin outer portion being located outside the housing cover member in a cover thickness direction; a resin inner portion located inside the case cover member in the cover thickness direction; and a resin hole interior, the resin hole interior being located in the insertion hole of the housing cover member and being integrally connected to the resin outer side portion and the resin inner side portion, The terminal member penetrates the resin outer portion, the inside of the resin hole, and the resin inner portion and extends inward in the thickness direction of the cover. The resin inner side portion of the resin member includes a pair of long side joint surfaces facing the long side direction of the cover and joined to the terminal member, The shell cover member and the resin member are configured so that when the power storage device is placed in a temperature environment of -40°C, the resin member is warped in a convex shape in the long side direction of the cover toward the outside in the thickness direction of the cover, and a pair of long side joint surfaces in the inner side portion of the resin press the terminal member in the long side direction of the cover respectively.

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

3. The power storage device according to claim 1 or 2, wherein: The terminal sealing portion of the terminal member which is airtightly joined to the resin member has terminal nanocolumns with a height of 50 nm or more on its surface, wherein the terminal nanocolumns are formed by particles with a diameter of 100 nm or less from the metal constituting the terminal member being connected in a beaded manner to form a columnar shape. The resin member is formed by filling a resin material constituting the resin member between the forested terminal nanocolumns and airtightly bonding to the terminal sealing portion.

4. A method for manufacturing an electric storage device, the electric storage device comprising: a housing cover member having an insertion hole and extending along the long side direction of the cover; a terminal member inserted into the insertion hole of the housing cover member; and a resin member that insulates the case cover member from the terminal member and is airtightly joined to the case cover member and the terminal member to fix the terminal member to the case cover member, The resin member has: a resin outer portion, the resin outer portion being located outside the housing cover member in a cover thickness direction; a resin inner portion located inside the case cover member in the cover thickness direction; and a resin hole interior, the resin hole interior being located in the insertion hole of the housing cover member and being integrally connected to the resin outer side portion and the resin inner side portion, The terminal member penetrates the resin outer portion, the inside of the resin hole, and the resin inner portion and extends inward in the thickness direction of the cover. The resin inner side portion of the resin member includes a pair of long side joint surfaces facing the long side direction of the cover and joined to the terminal member, The housing cover member and the resin member are configured such that when the electrical storage device is placed in a temperature environment of -40°C, the resin member is warped in a convex shape in the long side direction of the cover toward the outside in the thickness direction of the cover, and a pair of the long side joint surfaces in the resin inner side portion press the terminal member in the long side direction of the cover, respectively. The method for manufacturing an electric storage device includes 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 cover member.

5. The method for manufacturing an electric storage device according to claim 4, wherein: In the insert molding step, the resin member is molded so that the volume V1 of the resin outer portion is larger than the volume V2 of the resin inner portion (V1>V2).

6. The method for manufacturing an electrical storage device according to claim 4 or 5, wherein: The terminal sealing portion of the terminal member which is airtightly joined to the resin member has terminal nanocolumns with a height of 50 nm or more on its surface, wherein the terminal nanocolumns are formed by particles with a diameter of 100 nm or less from the metal constituting the terminal member being connected in a beaded manner to form a columnar shape. The resin member is formed by filling the space between the terminal nanocolumns standing in a forest with a resin material constituting the resin member and airtightly bonding with the terminal sealing portion. Prior to the insert molding step, the method for manufacturing the electrical storage device further comprises a terminal nanocolumn forming step, in which a pulsed laser is irradiated onto the terminal sealing portion of the terminal member while shifting the irradiation position, so that a forest of terminal nanocolumns is formed on the terminal sealing portion. In the insert molding step, the resin member is molded while filling the resin material between the terminal nano-columns standing in the terminal sealing portion.

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