Method for manufacturing an electricity storage device and an electricity storage device

Abstract

To provide a method of manufacturing a power storage device, and the like, capable of suppressing generation of a burned part on a scattered light arrival surface where scattered light of laser light directly arrives at, of outer surfaces of resin members for isolating between a lid member and terminal members.SOLUTION: A method of manufacturing a power storage device 1 includes: a closing step S2 of covering an opening 21 of a main body member 20 with a lid member 30 of a lid assembly 7; and a welding step S3 of laser welding the whole circumference of the opening 21 of the main body member 20 and a peripheral edge part 31 of the lid member 30. The resin members 70 and 80 are configured by making at least a part of scattered light arrival surfaces 70ma and 80ma where scattered light LC of laser light LB directly arrives at, of outer surfaces 70m and 80m become a smoothing region FM having a surface roughness Ra equal to or less than 0.6 μm.SELECTED DRAWING: Figure 8

Description

[Technical Field]

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

[0002] A known energy storage device is a rectangular battery in which positive and negative terminal members are fixed to a rectangular box-shaped case via a resin member. Specifically, the case comprises a base-closed rectangular cylindrical body member having a rectangular annular opening, and a rectangular plate-shaped lid member laser-welded to the body member along its entire periphery so as to close the opening. The positive and negative terminal members are inserted into a pair of insertion holes drilled in the lid member, extending from the inside to the outside of the case. A pair of resin members are bonded to the lid member and the terminal members, respectively, while insulating the lid member from the positive and negative terminal members. Related prior art includes, for example, Patent Document 1 (see Figures 1 and 2 of Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-086813 Summary of the Invention [Problem to be solved by the invention]

[0004] However, during the manufacturing process of such a battery, when the opening of the main body member is covered with a cover member to which a terminal member has already been fixed, and the opening of the main body member and the peripheral edge of the cover member are laser welded all around, scattered laser light can reach directly the outer surface of the resin member that insulates between the cover member and the terminal member, and burnt areas can occur on the surface where this scattered light reaches.

[0005] The present invention has been made in consideration of the current situation, and provides a method for manufacturing an electricity storage device and an electricity storage device that can prevent burnt areas from occurring on the outer surface of the resin member that insulates between the lid member and the terminal member, the surface that is directly reached by scattered laser light, when a main body member and a 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 main body member having an opening, and a lid member laser-welded to the main body member around the entire circumference in a form that closes the opening, a terminal member inserted into an insertion hole that penetrates the lid member in a lid thickness direction, and a resin member joined to the insertion hole peripheral portion of the lid member and the terminal member while insulating between the insertion hole peripheral portion that surrounds the insertion hole of the lid member and the terminal member, wherein the method includes the steps of: and a welding step of irradiating laser light to the opening of the main body member and the peripheral edge of the lid member, and laser-welding the opening and the peripheral edge along the entire circumference to form the case, wherein the resin member has an outer surface exposed to the outside of the case, at least a portion of which is a scattered light reaching surface that receives scattered light emitted from an irradiated portion irradiated with the laser light, among the opening of the main body member and the peripheral edge of the lid member, as a smoothed region having a surface roughness Ra of 0.6 μm or less.

[0007] The manufacturing method for the above-described electricity storage device uses a lid assembly having a resin member in which at least a portion of the outer surface where scattered light reaches is a smoothed region with a surface roughness Ra of 0.6 μm or less. As a result, in the welding process, even if scattered light of the laser beam directly reaches the smoothed region, it is easily reflected and is less likely to be absorbed by the resin member. As a result, scorching is less likely to occur in the smoothed region, and scorching on the scattered light reach surface can be suppressed.

[0008] The "smoothed region" on the outer surface of the resin member may be at least a portion of the scattered light arrival surface, or may be only a portion of the scattered light arrival surface, the entire scattered light arrival surface, or even the entire outer surface including the scattered light arrival surface. The surface roughness Ra of the smoothed region is preferably 0.3 μm or less, and more preferably 0.1 μm or less. This is because the scattered laser light is more easily reflected by the smoothed region, making it less likely that burnt areas will occur in the smoothed region.

[0009] The following method can be used to set the surface roughness Ra of the outer surface of the resin member, such as the surface where scattered light reaches, to 0.6 μm or less. (1) In a mold for molding a resin member, the surface molding surface for molding the outer surface of the resin member is mirror-finished. (2) Polishing the outer surface of the resin component. (3) Treat the outer surface of the resin component with a chemical. (4) The outer surface of the resin member is irradiated with infrared rays to melt the surface. (5) A hot plate is pressed against the outer surface of the resin part to melt the surface. The surface roughness Ra of the outer surface of the resin member can be measured using a known contact roughness meter, or a known non-contact roughness meter. Examples of "electricity storage devices" include secondary batteries such as lithium ion secondary batteries, capacitors such as lithium ion capacitors, and all-solid-state batteries.

[0010] (2) The method for manufacturing an electric storage device according to (1) may further include a lid assembly forming step, prior to the closing step, of insert-molding the resin member with the terminal member inserted into the insertion hole of the lid member to form the lid assembly, and the lid assembly forming step may be a method for manufacturing an electric storage device in which the resin member including the smoothed region is molded using a mold having a mirror-finished smoothed region molding surface that molds the smoothed region, among the surface molding surfaces that mold the outer surface of the resin member.

[0011] In the above-described method for manufacturing an electricity storage device, in the lid assembly forming step, the resin member having the smoothed region is molded using the above-described mold having a mirror-finished smoothed region molding surface on the surface molding surface, so that the smoothed region can be molded on the outer surface of the resin member simultaneously with molding the resin member.

[0012] (3) Furthermore, in the method for manufacturing an electricity storage device according to (1), it is preferable that the resin member has the entire outer surface as the smoothed region.

[0013] In the method for manufacturing an electricity storage device described above, the entire outer surface of the resin member is made into a smoothed region with a surface roughness Ra of 0.6 μm or less, which makes it easier for scattered laser light to be reflected at any part of the outer surface of the resin member, thereby suppressing the occurrence of burnt areas.

[0014] (4) The method for manufacturing an electric storage device according to (3) further includes a lid assembly forming step of, prior to the closing step, insert-molding the resin member with the terminal member inserted into the insertion hole of the lid member to form the lid assembly, and the lid assembly forming step may be a method for manufacturing an electric storage device in which the resin member is molded using a mold having a mirror-finished surface on the entire surface molding surface that forms the outer surface of the resin member, so that the entire outer surface becomes the smoothed area.

[0015] In the above-described method for manufacturing an electricity storage device, in the lid assembly forming step, the resin member having the entire outer surface formed as a smoothed region is molded using the above-described mold having the entire surface formed as a mirror finish. Therefore, the smoothed region can be molded on the entire outer surface of the resin member simultaneously with molding the resin member.

[0016] (5) Yet another aspect is an electricity storage device including: a case having a bottomed, cylindrical main body member having an opening; and a lid member laser-welded to the main body member around its entire circumference in a manner that closes the opening; a terminal member inserted into an insertion hole that penetrates the lid member in the thickness direction of the lid; and a resin member joined to the insertion hole periphery of the lid member and to the terminal member while insulating the terminal member from the insertion hole periphery surrounding the insertion hole of the lid member, wherein the resin member has an outer surface exposed to the outside of the case, and at least a portion of a scattered light reaching surface that is directly reached by scattered light radiated from an irradiated portion irradiated with laser light, the scattered light radiating from the opening of the main body member and the peripheral edge of the lid member, is a smoothed region having a surface roughness Ra of 0.6 μm or less.

[0017] In the above-described electricity storage device, at least a portion of the outer surface of the resin member where the scattered light reaches is made into a smoothed region, which prevents the occurrence of scorched areas on the surface of the resin member where the scattered light reaches, thereby maintaining the original appearance of the resin member and preventing a decrease in insulation resistance between the cover member and the terminal member due to the scorched areas.

[0018] (6) In the electricity storage device according to (5), the resin member may have the entire outer surface as the smoothed region.

[0019] In the above-described electricity storage device, the entire outer surface of the resin member is made into a smoothed region, which prevents scorching from occurring on the entire outer surface of the resin member, thereby maintaining the original appearance of the resin member and preventing a decrease in insulation resistance between the lid member and the terminal member due to the scorched portion. [Brief explanation of the drawings]

[0020] [Figure 1] FIG. 1 is a perspective view of a battery according to an embodiment. [Figure 2] 1 is a cross-sectional view of a battery according to an embodiment taken along the battery height direction and the battery width direction. [Figure 3]1A and 1B are enlarged partial cross-sectional views of the opening of the main body member and the peripheral edge of the cover member of the battery according to the embodiment, where (a) is an enlarged partial cross-sectional view along the battery height direction and battery width direction, and (b) is an enlarged partial cross-sectional view along the battery height direction and battery thickness direction. [Figure 4] 3 is a flowchart of a method for manufacturing a battery according to an embodiment. [Figure 5] 10A and 10B are explanatory views showing a lid assembly formed in a lid assembly forming step in the manufacturing method of the battery according to the embodiment. [Figure 6] 1A and 1B are explanatory diagrams showing the state in which molten resin is injected into a mold in the lid assembly formation process in a manufacturing method for a battery according to an embodiment, where (a) is an explanatory diagram of a partially enlarged cross section along the battery height direction and battery width direction, and (b) is an explanatory diagram of a partially enlarged cross section along the battery height direction and battery thickness direction. [Figure 7] 10 is an explanatory view showing the state in which the opening of the body member is closed with the lid member that forms the lid assembly in the closing step in the manufacturing method of the battery according to the embodiment. FIG. [Figure 8] 1A and 1B are explanatory diagrams showing how the opening (long side opening) of the main body member and the peripheral portion (long side peripheral portion) of the cover member are laser welded in the welding process in the manufacturing method of the battery according to the embodiment, where (a) is an explanatory diagram showing the start of irradiation of the laser light, and (b) is an explanatory diagram showing the formation of a molten metal portion by irradiation of the laser light. DETAILED DESCRIPTION OF THE INVENTION

[0021] Hereinafter, embodiments 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 1, Fig. 2 shows a cross-sectional view of the entire battery 1, and Fig. 3 shows an enlarged cross-sectional view of a portion of the battery 1 near an opening 21 of a main body member 20 and a peripheral edge portion 31 of a lid member 30. In the following description, the battery height direction AH, battery width direction BH, and battery thickness direction CH of the battery 1 will be defined as the directions shown in Figs. 1 to 3. The battery 1 is a prismatic (rectangular) sealed lithium ion secondary battery that is installed in vehicles such as hybrid cars, plug-in hybrid cars, and electric cars.

[0022] The battery 1 is composed of a case 10, an electrode assembly 40 housed within the case 10, and positive and negative terminal members 50, 60 supported on the case top 11 of the case 10 via resin members 70, 80. Inside the case 10, the electrode assembly 40 is covered by a bag-shaped insulating holder 5 made of insulating film and opening to the upper side AH1 in the battery height direction AH. The case 10 also contains an electrolyte 3, a portion of which is impregnated within the electrode assembly 40 and the remainder of which is pooled on the case bottom 12 of the case 10.

[0023] Of these, the case 10 is a rectangular box made of metal (aluminum in this embodiment) and has a rectangular case top 11 located on the upper side AH1 in the battery height direction AH, a rectangular case bottom 12 opposite it and located on the lower side AH2 in the battery height direction AH, and four rectangular case sides (a pair of case long sides 13, 14 and a pair of case short sides 15, 16) connecting the two.

[0024] The case 10 is composed of a main body member 20 and a lid member 30. The main body member 20 is a rectangular cylindrical member with a bottom and a rectangular annular opening 21 on the upper side AH1 in the battery height direction AH. The main body member 20 forms the case bottom 12, the case long sides 13 and 14, and the case short sides 15 and 16 of the case 10. The lid member 30 is a rectangular plate and forms the case upper portion 11 of the case 10. The lid member 30 is laser-welded to the main body member 20 along its entire periphery so as to close the opening 21 of the main body member 20, and a melt-solidified portion 18 is formed between the lid member 30 and the main body member 20. Specifically, the melt-solidified portion 18 is formed by welding a pair of long side openings 21b of the rectangular annular opening 21 of the main body member 20 to a pair of long side peripheral edges 31b of the rectangular annular peripheral edge 31 of the lid member 30 (see FIG. 3(b)). In addition, a pair of short side openings 21c of the opening 21 of the main body member 20 and a pair of short side peripheral portions 31c of the peripheral portion 31 of the cover member 30 are welded together to form a melted and solidified portion 18 (see Figure 3(a)).

[0025] The cover member 30 is provided with a safety valve 19 that breaks and opens when the internal pressure of the case 10 exceeds the valve opening pressure. The cover member 30 also has a liquid injection hole 30k that communicates between the inside and outside of the case 10, and is airtightly sealed with a disk-shaped sealing member 39 made of aluminum. Furthermore, rectangular insertion holes 33h, 34h penetrating in the lid thickness direction DH are provided in the lid member 30 near an end on one side BH1 and near an end on the other side BH2 in the battery width direction BH, respectively. A positive electrode terminal member 50 made of aluminum is inserted into one insertion hole 33h and is fixed to the lid member 30 while being insulated from the lid member 30 via a resin member 70. A negative electrode terminal member 60 made of copper is inserted into the other insertion hole 34h and is fixed to the lid member 30 while being insulated from the lid member 30 via a resin member 80.

[0026] These terminal members 50, 60 each have a rectangular plate-shaped external terminal portion 51, 61 arranged on the cover member 30, and internal terminal portions 52, 62 arranged mainly within the case 10 and connected to the external terminal portions 51, 61 via insertion holes 33h, 34h in the cover member 30. The positive electrode internal terminal portion 52 is joined to and conductively connected with the positive electrode tab 40a of the electrode assembly 40 within the case 10. On the other hand, the negative electrode internal terminal portion 62 is joined to and conductively connected with the negative electrode tab 40b of the electrode assembly 40 within the case 10.

[0027] The positive electrode resin member 70 surrounds the insertion hole 33h of the lid member 30, and is bonded to the insertion hole peripheral portion 33 of the lid member 30 and the terminal member 50 while insulating the rectangular annular insertion hole peripheral portion 33, which has a pair of long side peripheral portions 33e and a pair of short side peripheral portions 33f, from the terminal member 50. Similarly, the negative electrode resin member 80 surrounds the insertion hole 34h of the lid member 30, and is bonded to the insertion hole peripheral portion 34 of the lid member 30 and the terminal member 60 while insulating the rectangular annular insertion hole peripheral portion 34, which has a pair of long side peripheral portions 34e and a pair of short side peripheral portions 34f, from the terminal member 60.

[0028] These resin members 70, 80 are made of polyphenylene sulfide (PPS) and have rectangular plate-shaped external insulating portions 71, 81 arranged on the lid member 30, and internal insulating portions 72, 82 arranged inside the case 10 and in the insertion holes 33h, 34h of the lid member 30 and connected to the external insulating portions 71, 81. Of these, the external insulating portions 71, 81 insulate between the external terminal portions 51, 61 of the terminal members 50, 60 and the insertion hole surrounding portions 33, 34 of the lid member 30. On the other hand, the internal insulating portions 72, 82 insulate between the internal terminal portions 52, 62 of the terminal members 50, 60 and the insertion hole surrounding portions 33, 34 of the lid member 30.

[0029] Of the resin member 70, the outer surface 70m exposed to the outside of the case 10 has a first outer surface 70m1 facing the upper side AH1 in the battery height direction AH, a second outer surface 70m2 and a third outer surface 70m3 facing the battery thickness direction CH, a fourth outer surface 70m4 facing one side BH1 in the battery width direction BH, and a fifth outer surface 70m5 facing the other side BH2. Also, of the resin member 80, the outer surface 80m exposed to the outside of the case 10 has a first outer surface 80m1 facing the upper side AH1 in the battery height direction AH, a second outer surface 80m2 and a third outer surface 80m3 facing the battery thickness direction CH, a fourth outer surface 80m4 facing the other side BH2 in the battery width direction BH, and a fifth outer surface 80m5 facing one side BH1.

[0030] In the resin members 70, 80 of this embodiment, the portions of the outer surfaces 70m, 80m excluding the first outer surfaces 70m1, 80m1, i.e., the second outer surfaces 70m2, 80m2, the third outer surfaces 70m3, 80m3, the fourth outer surfaces 70m4, 80m4, and the fifth outer surfaces 70m5, 80m5, are the scattered light arrival surfaces 70ma, 80ma. As will be described later, these scattered light arrival surfaces 70ma, 80ma are portions of the opening 21 of the main body member 20 and the peripheral portion 31 of the lid member 30 where scattered light LC emitted from the irradiated portion P irradiated with the laser light LB directly reaches. In the resin members 70, 80 of this embodiment, the entire outer surfaces 70m, 80m, including the entire scattered light arrival surfaces 70ma, 80ma, are smoothed regions FM having a surface roughness Ra of 0.6 μm or less (specifically, 0.1 μm). This prevents the occurrence of burnt portions BP (see FIG. 8(b)) on the entire outer surfaces 70m and 80m.

[0031] The electrode assembly 40 is a flattened rectangular parallelepiped, stacked electrode assembly in which multiple positive electrode plates 41 and multiple negative electrode plates 42, each rectangular and extending in the battery height direction AH and battery width direction BH, are alternately stacked in the battery thickness direction CH with separators 43 interposed between them, each made of a porous resin film. Each positive electrode plate 41 has a positive electrode current collector 41r extending to the upper side AH1. The positive electrode current collectors 41r overlap each other in the thickness direction to form the positive electrode tab 40a. As described above, this positive electrode tab 40a is connected to the internal terminal portion 52 of the positive electrode terminal member 50. Each negative electrode plate 42 has a negative electrode current collector 42r extending to the upper side AH1. The negative electrode current collectors 42r overlap each other in the thickness direction to form the negative electrode tab 40b. As described above, this negative electrode tab 40b is connected to the internal terminal portion 62 of the negative electrode terminal member 60.

[0032] In the battery 1 of this embodiment, the entire outer surfaces 70m, 80m of the resin members 70, 80, including the scattered light reaching surfaces 70ma, 80ma, are smoothed regions FM having a surface roughness Ra of 0.6 μm or less. This prevents the occurrence of burnt areas BP on the entire outer surfaces 70m, 80m of the resin members 70, 80, so that the original appearance of the resin members 70, 80 can be maintained and a decrease in insulation resistance between the cover member 30 and the terminal members 50, 60 due to the burnt areas BP can be prevented.

[0033] Next, a method for manufacturing the battery 1 will be described (see FIGS. 4 to 8). First, in the "lid assembly formation step S1" (see FIG. 4), the lid assembly 7 is formed (see FIGS. 5 and 6(a) and 6(b)). That is, the lid member 30 and terminal members 50, 60 are prepared, and resin members 70, 80 are insert-molded to integrate the terminal members 50, 60 with the lid member 30 via the resin members 70, 80. Specifically, the lid member 30 is obtained by pressing an aluminum plate to form the liquid injection hole 30k, insertion holes 33h, 34h, and safety valve 19. The positive electrode terminal member 50 is obtained by pressing an aluminum plate, and the negative electrode terminal member 60 is obtained by pressing a copper plate.

[0034] Next, of the mold DE having an upper mold DE1 and a lower mold DE2, first, the lid member 30 is placed in a predetermined position in the lower mold DE2 (see FIGS. 6(a) and 6(b)). Next, the terminal members 50 and 60 are inserted into the insertion holes 33h and 34h of the lid member 30 placed in the lower mold DE2, respectively. After that, the upper mold DE1 is placed on top of the lower mold DE2 and the mold DE is closed. Next, molten resin MR is injected into the mold DE and then cooled to form the resin members 70 and 80. Thereafter, the upper mold DE1 is moved upward, and the composite molded product 7Y, in which the terminal members 50 and 60 are integrated with the lid member 30 via the resin members 70 and 80, is removed from the lower mold DE2.

[0035] In this insert molding, the outer surfaces 70m, 80m of the resin members 70, 80 are molded by a part (surface molding surface Dim) of the inner surface Di of the upper mold DE1. Specifically, of the outer surfaces 70m, 80m of the resin members 70, 80, the first outer surfaces 70m1, 80m1 are each molded by the first surface molding surface Dim1 (see FIGS. 6(a) and 6(b)) of the surface molding surface Dim of the upper mold DE1. Furthermore, the second outer surfaces 70m2, 80m2 of the outer surfaces 70m, 80m are each molded by the second surface molding surface Dim2 (see FIG. 6(b)) of the surface molding surface Dim. Furthermore, the third outer surfaces 70m3, 80m3 of the outer surfaces 70m, 80m are each molded by the third surface molding surface Dim3 (see FIG. 6(b)) of the surface molding surface Dim. Of the outer surfaces 70m, 80m, fourth outer surfaces 70m4, 80m4 are each formed by the fourth surface molding surface Dim4 (see FIG. 6(a)) of the surface molding surface Dim. Of the outer surfaces 70m, 80m, fifth outer surfaces 70m5, 80m5 are each formed by the fifth surface molding surface Dim5 (see FIG. 6(a)) of the surface molding surface Dim. In this embodiment, the entire surface molding surface Dim of the upper mold DE1 (first surface molding surface Dim1, second surface molding surface Dim2, third surface molding surface Dim3, fourth surface molding surface Dim4, and fifth surface molding surface Dim5) is a smoothing region molding surface Dimb that forms a smoothing region FM, which will be described later.

[0036] In this embodiment, the entire inner surface Di of the upper mold DE1 is mirror-finished, and therefore the entire surface molding surface Dim (smoothed region molding surface Dimb) is mirror-finished. As a result, the entire outer surfaces 70m, 80m (first outer surfaces 70m1, 80m1, second outer surfaces 70m2, 80m2, third outer surfaces 70m3, 80m3, fourth outer surfaces 70m4, 80m4, and fifth outer surfaces 70m5, 80m5) of the resin members 70, 80 molded by the surface molding surface Dim of the upper mold DE1 become smoothed regions FM having a surface roughness Ra of 0.6 μm or less (specifically, 0.1 μm).

[0037] Next, an electrode body 40 is prepared by laminating a positive electrode plate 41, a negative electrode plate 42, and a separator 43, and the internal terminal portions 52, 62 of the terminal members 50, 60 of the composite molded product 7Y described above are connected by welding to the positive electrode tab 40a and the negative electrode tab 40b of the electrode body 40, respectively (see FIG. 5). Thereafter, the electrode body 40 is wrapped in a bag-shaped insulating holder 5. In this way, a lid assembly 7 consisting of the lid member 30, the terminal members 50, 60, the resin members 70, 80, the electrode body 40, and the insulating holder 5 is formed.

[0038] Next, in the "closing step S2" (see FIG. 4), the main body member 20 is prepared, the electrode body 40 covered with the insulating holder 5 of the lid assembly 7 is inserted into the main body member 20, and the opening 21 of the main body member 20 is closed with the lid member 30 (see FIG. 7). Specifically, the pair of long-side peripheral edges 31b of the peripheral edge 31 of the lid member 30 are respectively opposed to the pair of long-side openings 21b of the opening 21 of the main body member 20, and the pair of short-side peripheral edges 31c of the peripheral edge 31 of the lid member 30 are respectively opposed to the pair of short-side openings 21c of the opening 21 of the main body member 20, thereby closing the opening 21 of the main body member 20 with the lid member 30.

[0039] Next, in the "welding process S3" (see Figure 4), laser light LB is irradiated onto the opening 21 of the main body member 20 and the peripheral edge 31 of the cover member 30 from the outside DH1 in the cover thickness direction DH of the cover member 30 (the upper side AH1 in the battery height direction AH), and the opening 21 and the peripheral edge 31 are melted and mixed to form a molten metal portion 18Z, which is then solidified to form a molten and solidified portion 18, performing laser welding around the entire circumference to form the case 10 (see Figures 8(a) and (b)).

[0040] At this time, scattered light LC emitted from the irradiated portion P of the laser light LB directly reaches parts (second outer surfaces 70m2, 80m2, third outer surfaces 70m3, 80m3, fourth outer surfaces 70m4, 80m4, and fifth outer surfaces 70m5, 80m5) of the outer surfaces 70m, 80m of the resin members 70, 80. If the surface roughness Ra of these scattered light reaching surfaces 70ma, 80ma is large, specifically, if the surface roughness Ra is greater than 0.6 μm, the scattered light LC is less likely to be reflected by the scattered light reaching surfaces 70ma, 80ma and is more likely to be absorbed by the resin members 70, 80, which makes it more likely that scorched portions BP will occur on the scattered light reaching surfaces 70ma, 80ma. In particular, of the scattered light reaching surfaces 70ma, 80ma, the second outer surfaces 70m2, 80m2 and the third outer surfaces 70m3, 80m3 are close to the irradiated area P of the laser light LB, and are irradiated with high-intensity scattered light LC, so burnt areas BP are particularly likely to occur.

[0041] In contrast, in this embodiment, the entire outer surfaces 70m, 80m of the resin members 70, 80 (first outer surfaces 70m1, 80m1, second outer surfaces 70m2, 80m2, third outer surfaces 70m3, 80m3, fourth outer surfaces 70m4, 80m4, and fifth outer surfaces 70m5, 80m5) are smoothed regions FM having a surface roughness Ra of 0.6 μm or less, specifically 0.1 μm. Therefore, the scattered light LC of the laser beam LB is easily reflected by any portion of the outer surfaces 70m, 80m and is not easily absorbed by the resin members 70, 80, thereby preventing the occurrence of burnt portions BP in any portion of the outer surfaces 70m, 80m.

[0042] Next, in the "pouring and sealing step S4," the electrolyte 3 is poured into the case 10 through the pouring hole 30k, and the electrolyte 3 is impregnated into the electrode body 40. Thereafter, the pouring hole 30k is covered from the outside with a sealing member 39, and the sealing member 39 is welded to the lid member 30 around its entire periphery to hermetically seal the gap between the sealing member 39 and the lid member 30. Next, in the "initial charging and aging step S5," a charging device (not shown) is connected to the battery 1, and the battery 1 is initially charged. After that, the initially charged battery 1 is left to stand for a predetermined time to age the battery 1. In this way, the battery 1 is completed.

[0043] The manufacturing method for the battery 1 of this embodiment uses a lid assembly 7 having resin members 70, 80 in which the entire outer surfaces 70m, 80m, including the scattered light reaching surfaces 70ma, 80ma, are smoothed to form smoothed regions FM with a surface roughness Ra of 0.6 μm or less. As a result, in the welding step S3, even if the scattered light LC of the laser beam LB directly reaches the entire outer surfaces 70m, 80m of the resin members 70, 80, it is easily reflected and is less likely to be absorbed by the resin members 70, 80. This makes it possible to prevent the occurrence of scorched areas BP in any part of the outer surfaces 70m, 80m.

[0044] In this embodiment, in the lid assembly forming step S1, the resin members 70, 80 having the entire outer surfaces 70m, 80m formed as smoothed regions FM are molded using an upper mold DE1 in which the entire surface molding surface Dim is mirror-finished. Therefore, the smoothed regions FM can be molded over the entire outer surfaces 70m, 80m of the resin members 70, 80 at the same time as molding the resin members 70, 80.

[0045] Although the present invention has been described above in accordance with the embodiments, it goes without saying that the present invention is not limited to the embodiments and can be modified and applied as appropriate within the scope of the invention. For example, in the embodiment, not only a part of the scattered light arrival surface 70ma, 80ma but also the entire outer surface 70m, 80m of the resin member 70, 80 is made into the smoothed region FM having a surface roughness Ra of 0.6 μm or less, but this is not limited to this. Only a part of the scattered light arrival surface 70ma, 80ma (for example, only the second outer surface 70m2, 80m2 and the third outer surface 70m3, 80m3, or only the second outer surface 70m2, 80m2, the third outer surface 70m3, 80m3, and the fourth outer surface 70m4, 80m4) may be made into the smoothed region FM. In the embodiment, a laminated electrode body 40 is exemplified as the electrode body housed in the case 10, but the electrode body may be a flat wound electrode body. Also, a plurality of electrode bodies may be housed in the case. [Explanation of symbols]

[0046] 1. Battery (energy storage device) 7 Lid Assembly 7Y composite molded product 10 cases 18 Melting and solidification section 20 Main body member 21 Opening 30 Lid member 31 Periphery 33, 34 Surrounding area of ​​insertion hole 33h, 34h Insertion holes 40 Electrode body 50,60 Terminal material 70,80 Resin material 70m,80m outer surface 70ma,80ma Scattered light reaching surface LB laser light LC scattered light P Irradiated area BP burnt area FM smoothing area DE mold DE1 Upper die Dim surface molding surface Dimb smoothing area molding surface DE2 lower mold S1 Lid assembly forming process S2 occlusion process S3 welding process S4 Liquid injection / sealing process S5 initial charging and aging process

Claims

1. a case including a bottomed tubular main body member having an opening, and a cover member that is laser welded to the main body member over an entire periphery thereof in a manner that closes the opening; a terminal member inserted into an insertion hole passing through the cover member in a thickness direction of the cover; a resin member bonded to the insertion hole surrounding portion of the cover member and the terminal member while insulating the insertion hole surrounding portion of the cover member and the terminal member. A method for manufacturing an electricity storage device, comprising: a closing step of closing the opening of the main body member with the lid member of a lid assembly formed by integrating the terminal member with the lid member via the resin member; a welding process of irradiating a laser beam to the opening of the main body member and a peripheral portion of the cover member, and laser-welding the opening and the peripheral portion along their entire periphery to form the case, The resin member is Among the outer surfaces exposed to the outside of the case, at least a part of a scattered light reaching surface where scattered light radiated from an irradiated portion irradiated with the laser light directly reaches among the opening of the main body member and the peripheral portion of the cover member is made into a smoothed region having a surface roughness Ra of 0.6 μm or less. 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: a lid assembly forming step of forming the lid assembly by insert-molding the resin member in a state in which the terminal member is inserted into the insertion hole of the lid member prior to the closing step, The lid assembly forming step includes: The resin member including the smoothed region is molded using a mold having a mirror-finished smoothed region molding surface that molds the smoothed region among the surface molding surfaces that mold the outer surface of the resin member. 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 resin member is The entire outer surface is the smoothed region. A method for manufacturing an electricity storage device.

4. A method for producing the electricity storage device according to claim 3, comprising the steps of: a lid assembly forming step of forming the lid assembly by insert-molding the resin member in a state in which the terminal member is inserted into the insertion hole of the lid member prior to the closing step, The lid assembly forming step includes: The resin member is molded by using a mold having a surface molding surface which is entirely mirror-finished to mold the outer surface of the resin member, so that the entire outer surface of the resin member becomes the smoothed region. A method for manufacturing an electricity storage device.

5. a case including a bottomed tubular main body member having an opening, and a cover member that is laser welded to the main body member over an entire periphery thereof in a manner that closes the opening; a terminal member inserted into an insertion hole passing through the cover member in a thickness direction of the cover; a resin member bonded to the insertion hole surrounding portion of the cover member and the terminal member while insulating the insertion hole surrounding portion of the cover member and the terminal member. An electricity storage device, The resin member is Among the outer surfaces exposed to the outside of the case, at least a part of a scattered light reaching surface where scattered light radiated from an irradiated portion irradiated with laser light among the opening of the main body member and the peripheral portion of the cover member directly reaches is made into a smoothed region having a surface roughness Ra of 0.6 μm or less. Energy storage device.

6. The electricity storage device according to claim 5 , The resin member is The entire outer surface is the smoothed region. Energy storage device.

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