Method for manufacturing power storage device

Abstract

To provide a method for manufacturing a power storage device that can suppress the occurrence of burnt areas in a resin member that provides insulation between the periphery of an insertion hole in a case lid member and a terminal member when forming a case by laser welding.SOLUTION: A manufacturing method of a power storage device 1 includes a laser welding step S3 of irradiating the entire circumference of an opening 20c of a case body member 20 and the peripheral portion 30f of a case lid member 30 with laser light LC with the opening 20c of the case body member 20 being blocked by the case lid member 30 of a lid assembly 15 to perform laser welding, a shielding step S2 of disposing shielding members SA, SB in the lid assembly 15 to prevent scattered light LB of the laser light LC from reaching the resin members 70, 80 prior to the laser welding step S3, and a removal step S4 of removing the shielding members SA, SB after the laser welding step S3.SELECTED DRAWING: Figure 8

Description

[Technical field]

[0001] The present invention relates to a manufacturing method for an electricity storage device that includes a case in which a case lid member is welded to a case main body member, a terminal member inserted into an insertion hole in the case lid member, and a resin member that joins the terminal member to the case lid member while insulating the terminal member from the surrounding area of ​​the insertion hole in the case lid member, and fixes the terminal member to the case lid member. [Background technology]

[0002] As an electricity storage device, a rectangular battery in which positive and negative terminal members are fixed to a rectangular box-shaped case via a resin member is known. Specifically, the case is composed of a case body member in the shape of a rectangular cylinder with a bottom and a rectangular plate-shaped case lid member welded to the case body member over the entire circumference in a form that closes the opening. The positive and negative terminal members are inserted into insertion holes provided in the case lid member and extend from the inside of the case to the outside of the case, and the resin member is airtightly joined to the positive and negative terminal members while insulating the surroundings of the insertion holes of the case lid member from each other, thereby fixing the positive and negative terminal members to the case lid member. Such a battery is disclosed, for example, in Patent Document 1 (see Figs. 1 and 2, 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] Such batteries are manufactured as follows: the terminal members are fixed to the case lid member via a resin member by insert molding, crimping, or the like, and a lid assembly is formed by integrating these members. Next, the opening of the case body member is closed with the case lid member of this lid assembly, and the opening of the case body member and the periphery of the case lid member are laser welded all around to form a case. After that, the battery is completed by injecting an electrolyte into the case, or the like. However, during the above-mentioned laser welding, scattered light of the laser beam may reach the resin member that provides insulation between the case lid member and the terminal member, causing scorched portions in the resin member.

[0005] The present invention has been made in consideration of the current situation, and provides a manufacturing method for an electricity storage device that can suppress the occurrence of burnt areas in the resin member that insulates between the surrounding area of ​​the insertion hole in the case lid member and the terminal member when the case body member and the case lid member are laser welded to form a case. [Means for solving the problem]

[0006] (1) One aspect of the present invention for solving the above problem is a method for manufacturing an electricity storage device including a case having a bottomed cylindrical case body member having an opening, and a case lid member having an insertion hole and welded to the case body member around its entire circumference in a manner that closes the opening, a terminal member inserted into the insertion hole of the case lid member, and a resin member that bonds to an insertion hole peripheral portion of the case lid member that surrounds the insertion hole and the terminal member while insulating them from each other, the method including: attaching the resin member to the case lid member; a laser welding process for forming the case by irradiating laser light around the entire circumference of the opening of the case body member and the peripheral portion of the case lid member with the case lid member, with the opening of the case body member being blocked by the case lid member, a shielding process for disposing a shielding member on the lid assembly prior to the laser welding process, the shielding member preventing scattered light of the laser light from reaching the resin member, and a removal process for removing the shielding member after the laser welding process.

[0007] In the manufacturing method of the electric storage device described above, prior to the laser welding step of laser-welding the case body member and the case lid member, the above-mentioned shielding member is placed on the lid assembly in the shielding step. This makes it difficult for the scattered laser light to reach the resin member during laser welding in the laser welding step, so that it is possible to suppress the occurrence of scorched portions in the resin member.

[0008] 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. Examples of the "shielding member" include a shielding member made of metal and a shielding member made of ceramic. The shielding member may be in a form that covers the entire resin outer part of the resin member that is located on the outside of the case lid member in the lid thickness direction, or may be in a form that covers only a part of the resin outer part. Alternatively, the shielding member may be in a wall-like (partition-like) form that is disposed between the resin member and the peripheral part of the case lid member. The "resin member" may be a resin member insert-molded with the terminal member inserted into the insertion hole of the case lid member, or it may be a resin member formed separately from the case lid member and the terminal member and crimped and fixed together with the case lid member by the terminal member.

[0009] (2) In the method for manufacturing an electric storage device described in (1), preferably, the wavelength λ of the laser light is 0.5 μm or more, and the shielding member has an Ag plating layer in a portion where the scattered light of the laser light reaches.

[0010] Silver (Ag) is less likely to absorb laser light with a wavelength λ of 0.5 μm or more than iron (Fe) or aluminum (Al), and is less likely to melt even if the scattered light of this laser light reaches it. Therefore, by providing an Ag plating layer on the portion of the shielding member that receives the scattered light of the laser light as described above, the shielding member becomes less likely to melt due to the scattered light of the laser light, and the shielding member can be reused repeatedly.

[0011] (3) In the method for manufacturing an electric storage device described in (1), preferably, the wavelength λ of the laser light is 0.9 μm or more, and the portion of the shielding member that is reached by the scattered light of the laser light is made of Cu.

[0012] Copper (Cu) is less likely to absorb laser light with a wavelength λ of 0.9 μm or more than Fe or Al, and is less likely to dissolve even when the scattered light of this laser light reaches it. Therefore, by forming the portion of the shielding member that receives the scattered light of the laser light from Cu as described above, the shielding member becomes less likely to dissolve due to the scattered light of the laser light, and the shielding member can be reused repeatedly.

[0013] (4) A method for manufacturing an electricity storage device according to any one of (1) to (3), wherein the shielding member is configured to be detachable from the resin member or the terminal member of the lid assembly, may be used.

[0014] Since the shielding member has the above-mentioned detachable configuration, the shielding member itself can temporarily fix the shielding member to the resin member or the terminal member, which prevents the shielding member from shifting from a predetermined position on the lid assembly or from being separated from the lid assembly when, for example, the lid assembly on which the shielding member is arranged is transported, making it easier to handle the lid assembly on which the shielding member is arranged.

[0015] (5) In the method for producing an electricity storage device according to (4), the shielding member may be formed by bending a metal plate.

[0016] The shielding member is made by bending a metal plate, and therefore can be an inexpensive shielding member.

[0017] (6) A method for manufacturing an electricity storage device as described in any one of (1) to (5), wherein the case lid member is a rectangular plate extending in a lid longitudinal direction, and a resin outer portion of the resin member located on the outside of the lid thickness direction of the case lid member has an outer shape of a rectangular plate and has a top surface facing outward in the lid thickness direction, a pair of long sides facing in the lid short direction along the lid longitudinal direction, and a pair of short sides facing in the lid longitudinal direction along the lid short direction, and the shielding member has a shape that prevents the scattered light of the laser light from reaching the pair of long sides of the resin member.

[0018] As described above, when the case lid member is a rectangular plate extending in the lid longitudinal direction and the resin outer portion of the resin member has a top surface, a pair of long sides, and a pair of short sides, the distance from the irradiated portion of the laser light to the long sides of the resin member is likely to be short, so that high-intensity scattered light is likely to reach the long sides of the resin member, and scorching is likely to occur on the long sides. In contrast, in the above-mentioned manufacturing method, the shielding member has a shape that prevents the scattered light of the laser light from reaching the pair of long sides of the resin member, so that scorching can be suppressed on the long sides of the resin member.

[0019] (7) The method for manufacturing an electricity storage device according to (6) may be such that the shielding member is longer in the lid longitudinal direction than the long side surface of the resin member.

[0020] Since the shielding member has a shape that is longer in the longitudinal direction of the lid than the long side of the resin member, it is possible to more appropriately prevent scattered laser light from reaching the long side of the resin member during the laser welding process and more appropriately suppress the occurrence of scorched areas on the long side of the resin member. [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] 3 is a partially enlarged cross-sectional view of the battery according to the embodiment, taken along the battery height direction and battery width direction, in the vicinity of a resin member. FIG. [Figure 4] 2 is a flowchart of a method for manufacturing a battery according to an embodiment. [Diagram 5] FIG. 2 is an explanatory diagram showing a lid assembly in accordance with an embodiment of the method for manufacturing a battery. [Figure 6] FIG. 2 is a perspective view of a shielding member in a battery manufacturing method according to an embodiment. [Figure 7] 1A and 1B are explanatory diagrams showing the state in which a shielding member is placed on a lid assembly in a shielding process in a battery manufacturing method according to an embodiment, where (a) is an explanatory diagram viewed in the short direction of the lid, and (b) is an explanatory diagram viewed in the long direction of the lid. [Figure 8] 11 is an explanatory diagram showing how, with a shielding member in place, an opening of a case body member and a peripheral portion of a case lid member are laser welded in a laser welding process in a manufacturing method for a battery according to an embodiment. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] (Embodiment) Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Fig. 1 shows a perspective view of a battery (electricity storage device) 1 according to this embodiment, and Fig. 2 shows a partially cutaway cross-sectional view of the battery 1. Fig. 3 shows a partially enlarged cross-sectional view of the battery 1 near resin members 70 and 80. 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 direction EH, and lid thickness direction FH of the case lid member 30 are defined as the directions shown in Figs. 1 to 3.

[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 form of a bottomed square cylinder having a rectangular opening 20c and accommodating an 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 all around, and a melted and solidified portion 25 is formed between the case body member 20 and the case lid member 30. 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] The terminal members 50, 60 are formed by pressing metal plates (aluminum plate for the positive electrode and copper plate for the negative electrode). The terminal members 50, 60 are 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 and consist of a rectangular terminal top plate portion 51, 61 extending in the lid longitudinal direction DH (battery width direction BH) and the lid short side direction EH (battery thickness direction CH), and a terminal extension portion 52, 62 extending from the terminal top plate portion 51, 61 to the inner side FH2 of the lid thickness direction FH (lower side AH2 in the battery height direction AH). The terminal extensions 52, 62 are bent at the ends of one side EH1 (one side CH1 in the battery thickness direction CH) of the terminal top plate portions 51, 61 in the lid short-side direction EH, extend to the inside FH2 in the lid thickness direction FH, pass through the insertion holes 30h1, 30h2 of the case lid member 30, and further extend through the resin members 70, 80 to the lower side AH2. The positive terminal extension 52 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 62 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.

[0029] Next, the resin members 70, 80 will be described. The resin members 70, 80 are insert-molded using a resin material containing a thermoplastic main resin (specifically, polyphenylene sulfide (PPS)), a thermoplastic elastomer, and a filler (specifically, a fibrous glass filler). The resin members 70, 80 are hermetically bonded to the insertion hole surrounding parts 30s1, 30s2 of the case lid member 30 and the terminal members 50, 60 while insulating between the insertion hole surrounding parts 30s1, 30s2 surrounding the insertion holes 30h1, 30h2 of the case lid member 30 and the terminal members 50, 60, and fix the terminal members 50, 60 to the case lid member 30.

[0030] The resin members 70, 80 consist of a resin outer portion 71, 81 located on the outer side FH1 of the case lid member 30 in the lid thickness direction FH, and a resin inner portion 72, 82 located within the insertion holes 30h1, 30h2 of the case lid member 30 and on the inner side FH2 of the lid thickness direction FH of the case lid member 30, and integrally connected to the resin outer portion 71, 81. The resin outer portion 71, 81 has a rectangular plate-like outer shape and has a rectangular ring-shaped top surface 71m1, 81m1 facing the outer side FH1 in the lid thickness direction FH, a pair of rectangular long side surfaces 71m2, 81m2 facing the lid short side direction EH along the lid longitudinal direction DH, and a pair of rectangular short side surfaces 71m3, 81m3 facing the lid longitudinal direction DH along the lid short side direction EH. The outer surfaces 70m, 80m of the resin members 70, 80 exposed to the outside of the case 10 are composed of the top surface 71m1, 81m1, the pair of long side surfaces 71m2, 81m2, and the pair of short side surfaces 71m3, 81m3. In the battery 1 of this embodiment, no burnt areas are formed on any of the outer surfaces 70m, 80m of the resin members 70, 80 (top surfaces 71m1, 81m1, long side surfaces 71m2, 81m2, and short side surfaces 71m3, 81m3).

[0031] Next, a manufacturing method of the battery 1 will be described (see Figs. 4 to 8). First, in the "lid assembly forming step S1" (see Fig. 4), the lid assembly 15 is formed (see Fig. 5). That is, the case lid member 30 and the terminal members 50, 60 are prepared, and the resin members 70, 80 are insert-molded to fix the terminal members 50, 60 to the case lid member 30 via the resin members 70, 80. The case lid member 30 is obtained by punching an aluminum plate into a predetermined shape, and forming therein the liquid injection hole 30k, the insertion holes 30h1, 30h2, and the safety valve 11. The positive electrode terminal member 50 is obtained by punching an aluminum plate into a predetermined shape and bending the aluminum plate. The negative electrode terminal member 60 is obtained by punching a copper plate into a predetermined shape and bending the copper plate.

[0032] Then, with the terminal members 50, 60 inserted into the insertion holes 30h1, 30h2 of the case lid member 30, the resin members 70, 80 are insert-molded using the above-mentioned resin material, and the terminal members 50, 60 are fixed to the case lid member 30 via the resin members 70, 80 (see FIG. 5). Thereafter, an electrode body 40 is prepared by laminating a positive electrode plate 41, a negative electrode plate 42, and a separator 43, and a terminal extension 52 of a positive electrode terminal member 50 is welded to a positive electrode current collecting portion 40c of the electrode body 40. Also, a terminal extension 62 of a negative electrode terminal member 60 is welded to a negative electrode current collecting portion 40d of the electrode body 40. Then, the electrode body 40 is wrapped in a bag-shaped insulating holder 7. In this manner, a lid assembly 15 is formed, which includes a case lid member 30, terminal members 50, 60, resin members 70, 80, the electrode body 40, and the insulating holder 7.

[0033] Next, in the "shielding step S2" (see FIG. 4), a shielding member SA that prevents the scattered light LB of the laser light LC from reaching the resin members 70, 80 in the laser welding step S3 described later is placed on the lid assembly 15 (see FIGS. 6 and 7). First, the shielding member SA will be described. This shielding member SA is formed by bending a rectangular metal plate MA with an Ag plating layer MAd formed on the entire surface of a stainless steel plate MAc. Therefore, the shielding member SA of this embodiment has an Ag plating layer MAd on the entire surface of the shielding member SA, including a region SAp where the scattered light LB of the laser light LC reaches in the laser welding step S3 described later.

[0034] The shielding member SA is configured to be detachable from the resin members 70, 80 of the lid assembly 15. The shielding member SA has a shape that prevents the scattered light LB of the laser light LC from reaching a pair of long side surfaces 71m2, 81m2 of the resin members 70, 80, and is longer in the lid longitudinal direction DH than the long side surfaces 71m2, 81m2 of the resin members 70, 80. Specifically, the shielding member SA is composed of a pair of side wall portions SA1 that cover the pair of long side surfaces 71m2, 81m2 of the resin members 70, 80, and a connecting portion SA2 that connects the side wall portions SA1 and is disposed on the outer side FH1 in the lid thickness direction FH of the top surfaces 71m1, 81m1 of the resin members 70, 80.

[0035] Of these, the side wall portion SA1 is a rectangular plate covering the entire long side surfaces 71m2, 81m2 of the resin members 70, 80, and its dimension in the lid longitudinal direction DH is longer than the dimension in the lid longitudinal direction DH of the long side surfaces 71m2, 81m2 (see FIG. 7(b)). The connecting portion SA2 is bent at multiple points and has two inverted V-shaped protruding portions SA3 protruding to the outside FH1 in the lid thickness direction FH, a pair of first flat plate portions SA4 connecting the side wall portions SA1 and the protruding portions SA3, and a second flat plate portion SA5 connecting the two protruding portions SA3. The first flat plate portion SA4 and the second flat plate portion SA5 are rectangular plate-shaped and extend along the top surfaces 71m1 and 81m1 of the resin members 70 and 80.

[0036] 7(a), when the two protruding portions SA3 of this shielding member SA are pressed in a direction in which they approach each other, the gap KG between the side wall portions SA1 widens, and the gap KG becomes larger than the dimension in the lid short-side direction EH of the resin members 70, 80. On the other hand, when the pressing is released, the gap KG between the side wall portions SA1 narrows, and the gap KG becomes smaller than the dimension in the lid short-side direction EH of the resin members 70, 80. Therefore, in the shielding step S2, the two protruding portions SA3 of the shielding member SA are pressed in a direction in which they approach each other, and in a state in which the gap KG between the side wall portions SA1 is widened, the shielding member SA is placed over the resin members 70, 80. When the pressing is then released, the gap KG between the side wall portions SA1 narrows, and the pair of side wall portions SA1 elastically grip the resin members 70, 80 in the lid short-side direction EH. This temporarily fixes the shielding member SA to the resin members 70, 80 of the lid assembly 15.

[0037] Next, in the "laser welding process S3" (see FIG. 4), the case body member 20 is prepared, the electrode body 40 covered with the insulating holder 7 of the above-mentioned lid assembly 15 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 (see FIG. 8). Then, the opening 20c of the case body member 20 and the peripheral portion 30f of the case lid member 30 are irradiated with laser light LC over the entire circumference, and airtight laser welding is performed to form the case 10 housing the electrode body 40 therein.

[0038] Specifically, using a fiber laser, laser light LC having a wavelength λ of 1.06 μm is irradiated to the opening 20c of the case body member 20 and the peripheral portion 30f of the case lid member 30 from the outside FH1 in the lid thickness direction FH of the case lid member 30, and laser welding is performed around the entire circumference to melt and mix the opening 20c and the peripheral portion 30f and then solidify them to form the molten and solidified portion 25, thereby forming the case 10. In this case, in the conventional method, the scattered light LB emitted from the irradiated portion P of the laser light LC directly reaches a part of the outer surface 70m, 80m of the resin member 70, 80 (the pair of long side surfaces 71m2, 81m2 and the pair of short side surfaces 71m3, 81m3), so that scorching is likely to occur on these long side surfaces 71m2, 81m2 and short side surfaces 71m3, 81m3. In particular, the long side surfaces 71m2, 81m2 are close to the irradiated portion P of the laser light LC, and the high-intensity scattered light LB reaches them, so that scorching is likely to occur.

[0039] In contrast, in this embodiment, the shielding member SA covers a part (the top surface 71m1 and the pair of long side surfaces 71m2, 81m2) of the outer surfaces 70m, 80m of the resin members 70, 80. Therefore, the scattered light LB of the laser light LC does not reach the top surface 71m1 and the pair of long side surfaces 71m2, 81m2 of the outer surfaces 70m, 80m of the resin members 70, 80, so that it is possible to prevent the top surface 71m1 and the long side surfaces 71m2, 81m2 of the resin members 70, 80 from being burnt.

[0040] In addition, the pair of short side surfaces 71m3, 81m3 of the outer surfaces 70m, 80m of the resin members 70, 80 are not covered with the shielding member SA. However, the short side surfaces 71m3, 81m3 are sufficiently separated from the irradiated portion P of the laser light LC, and even if the short side surfaces 71m3, 81m3 are not covered with the shielding member SA, the high-intensity scattered light LB does not reach the short side surfaces 71m3, 81m3, so no burnt parts are generated on the short side surfaces 71m3, 81m3. Therefore, no burnt parts are generated on any parts of the outer surfaces 70m, 80m of the resin members 70, 80 (the top surface 71m1, the pair of long side surfaces 71m2, 81m2, and the pair of short side surfaces 71m3, 81m3).

[0041] Next, in the "removal step S4" (see FIG. 4), the shielding member SA is removed. Specifically, the two protruding portions SA3 of the shielding member SA are pressed in a direction in which they approach each other, and the gap KG between the side wall portions SA1 is widened, and the shielding member SA is then lifted up. This makes it possible to easily remove the shielding member SA from the resin members 70, 80 and the lid assembly 15.

[0042] Next, in a "pouring and sealing step S5" (see FIG. 4), 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 S6", 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.

[0043] As described above, in the manufacturing method of the battery 1, the laser welding process S3 is performed with the shielding member SA placed in the lid assembly 15, so that the scattered light LB of the laser light LC is less likely to reach the resin members 70, 80, thereby preventing the occurrence of burnt areas in the resin members 70, 80. Furthermore, in this embodiment, an Ag plating layer MAd is provided on a portion SAp of the shielding member SA where the scattered light LB of the laser light LC reaches. The Ag plating layer MAd is difficult to absorb the laser light LC having a wavelength λ of 0.5 μm or more, and is difficult to dissolve even when the scattered light LB of the laser light LC reaches it. Therefore, since the shielding member SA is difficult to dissolve by the scattered light LB of the laser light LC, the shielding member SA can be reused repeatedly.

[0044] Furthermore, since the shielding member SA has a configuration that allows it to be detached from the resin members 70, 80 of the lid assembly 15, the shielding member SA itself can temporarily fix the shielding member SA to the resin members 70, 80 (to the lid assembly 15). This prevents the shielding member SA from shifting from a predetermined position on the lid assembly 15 or from being separated from the lid assembly 15 when, for example, transporting the lid assembly 15 on which the shielding member SA is arranged, making it easier to handle the lid assembly 15 on which the shielding member SA is arranged. Furthermore, since this shielding member SA is formed by bending a metal plate material MA, it can be an inexpensive shielding member.

[0045] In this embodiment, the case lid member 30 is a rectangular plate extending in the lid longitudinal direction DH, the resin outer portion 71, 81 of the resin member 70, 80 is a rectangular plate having a top surface 71m1, 81m1, a pair of long sides 71m2, 81m2, and a pair of short sides 71m3, 81m3, and the distance from the irradiated portion P of the laser light LC to the long sides 71m2, 81m2 of the resin member 70, 80 is short. Therefore, the high-intensity scattered light LB is likely to reach the long sides 71m2, 81m2 of the resin member 70, 80, and the long sides 71m2, 81m2 are likely to be burned. In contrast, in this embodiment, the shielding member SA has a form that prevents the scattered light LB from reaching the pair of long sides 71m2, 81m2 of the resin member 70, 80, so that the long sides 71m2, 81m2 of the resin member 70, 80 can be prevented from being burned. In addition, since the shielding member SA has a shape that is longer in the lid longitudinal direction DH than the long sides 71m2, 81m2 of the resin members 70, 80, it is possible to more appropriately prevent the scattered light LB of the laser light LC from reaching the long sides 71m2, 81m2 of the resin members 70, 80 in the laser welding process S3, and more reliably prevent the occurrence of burnt areas on the long sides 71m2, 81m2 of the resin members 70, 80.

[0046] (Variations) Next, a modified embodiment of the above embodiment will be described. Note that the description of the same parts as the embodiment will be omitted or simplified. The shielding member SA used in the embodiment has an Ag plating layer MAd on the entire surface of the shielding member SA, including the area SAp where the scattered light LB of the laser light LC arrives. In contrast, the shielding member SB used in this modified embodiment is different in that the entire shielding member SB, including the area SBp where the scattered light LB of the laser light LC arrives, is made of Cu.

[0047] Specifically, the shielding member SB of this modified embodiment is formed by bending a metal plate MB made of a copper plate. However, the shape of the shielding member SB is the same as that of the shielding member SA of the embodiment. That is, like the shielding member SA, the shielding member SB is composed of a pair of side wall portions SB1 and a connecting portion SB2 (two protruding portions SB3, a pair of first flat portion SB4 and second flat portion SB5). Therefore, the shielding member SB of this modified embodiment can be handled in the same way as the shielding member SA of the embodiment.

[0048] Even when the battery 1 is manufactured using such a shielding member SB, the shielding member SB makes it difficult for the scattered light LB of the laser light LC to reach the resin members 70, 80 during laser welding in the laser welding process S3, so that it is possible to prevent scorched portions from being generated in the resin members 70, 80. Furthermore, the portion SBp of the shielding member SB where the scattered light LB of the laser light LC reaches is formed of Cu. Therefore, the shielding member SB is difficult to dissolve by the scattered light LB of the laser light LC, so that the shielding member SB can be reused repeatedly. Other parts similar to those of the embodiment provide the same functions and effects as those of the embodiment.

[0049] Although the present invention has been described above with reference to the embodiments and modified forms, it goes without saying that the present invention is not limited to the embodiments and modified forms, and can be appropriately modified and applied without departing from the spirit of the present invention. For example, in the embodiment and the like, the shielding members SA, SB configured to be detachable from the resin members 70, 80 of the lid assembly 15 are exemplified as the shielding members, but are not limited to this. For example, if the terminal member has a terminal protruding portion that protrudes outward in the lid thickness direction beyond the resin member, the shielding member may be configured to be detachable from the terminal protruding portion of the terminal member of the lid assembly. [Explanation of symbols]

[0050] 1. Battery (energy storage device) 10 Cases 15 Lid Assembly 20 Case body material 20c opening 30 Case cover member 30f Periphery 30h1, 30h2 Through holes 30s1, 30s2 Surroundings of insertion hole 40 Electrode body 50,60 Terminal material 70,80 Resin material SA,SB Shielding material SAp, SBp (areas of the shielding material where scattered light of the laser beam reaches) SA1,SB1 Side wall part SA2,SB2 connection part SA3,SB3 protrusion SA4,SB4 1st flat plate part SA5,SB5 2nd flat plate part KG (side wall gap) MA,MB Metal plate material MAc Stainless Steel Plate MAd Ag plating layer LC Laser Light LB scattered light P Irradiated area S1 Lid assembly forming process S2 shielding process S3 Laser welding process S4 removal process

Claims

1. a case including a bottomed cylindrical case body member having an opening, and a case lid member having an insertion hole and welded to the case body member over an entire periphery in a manner to close the opening; a terminal member inserted into the insertion hole of the case lid member; a peripheral portion of the case lid member surrounding the insertion hole and a resin member that is joined to the terminal member while insulating the terminal member from the peripheral portion and fixes the terminal member to the case lid member. A method for manufacturing an electricity storage device, comprising: a laser welding process for forming the case by irradiating a laser beam to the entire periphery of the opening of the case body member and a peripheral portion of the case lid member and laser welding the opening of the case body member and the peripheral portion of the case lid member with the opening of the case body member and the peripheral portion of the case lid member while the opening of the case body member is closed by the case lid member in a lid assembly in which the terminal member is integrated with the case lid member via the resin member; a shielding step of disposing a shielding member on the lid assembly to prevent scattered light of the laser beam from reaching the resin member prior to the laser welding step; and a removal step of removing the shielding member after the laser welding step. A method for manufacturing an electricity storage device.

2. A method for producing the electricity storage device according to claim 1, comprising the steps of: The wavelength λ of the laser light is 0.5 μm or more, The shielding member has an Ag plating layer at a portion where the scattered light of the laser light reaches. A method for manufacturing an electricity storage device.

3. A method for producing the electricity storage device according to claim 1, comprising the steps of: The wavelength λ of the laser light is 0.9 μm or more, The shielding member is made of Cu at a portion where the scattered light of the laser light reaches. A method for manufacturing an electricity storage device.

4. A method for producing the electricity storage device according to any one of claims 1 to 3, comprising the steps of: The shielding member is configured to be detachable from the resin member or the terminal member of the lid assembly. 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 shielding member is formed by bending a metal plate. A method for manufacturing an electricity storage device.

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