Lead with insulation resin film

Abstract

To provide a lead with an insulation resin film improved in adhesiveness with a sheath.SOLUTION: A lead with an insulation resin film comprises a conductor 14 and an insulation resin film 15. In a case where an axis along two sides of the conductor is defined as an X axis and an axis orthogonal with the X axis is defined as a Y axis, the conductor includes in both ends along the X axis conductor taper parts 14B which become thinner as they are away from a first center that is a center of the conductor along the X axis. The insulation resin film is disposed so as to include margin parts 40 which cross the conductor along the X axis, protrude from both the ends of the conductor and overlap each other. A laminate obtained by laminating the insulation resin film and the conductor includes a resin taper part on a cross section along the X axis. In a case where the end of the conductor taper part close to the first center is defined as a first conductor end 43, the end of the resin taper part close to the first center is defined as a first resin end 41 and the end away from the first center is defined as a second resin end 42, the first resin end is located at the same position as the first conductor end or at a position closer to the first center than the first conductor end, and the second resin end is located at a position farther from the first center than the end of the conductor.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present disclosure relates to a lead with an insulating resin film.

Background Art

[0002] Patent Document 1 discloses a lead member in which a pair of insulating resin films are bonded to positions other than both ends in the length direction of a conductor made of a metal foil from both sides of the conductor.

Prior Art Document

Patent Document

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When a lead with an insulating resin film in which insulating resin films are disposed on the upper and lower surfaces of a conductor is heat-sealed to an exterior body, a gap may occur between the exterior body and the insulating resin film of the lead with the insulating resin film.

[0005] The gap is a factor that weakens the adhesion between the exterior body and the insulating film.

[0006] An object of the present disclosure is to provide a lead with an insulating resin film having excellent adhesion to an exterior body.

Means for Solving the Problems

[0007] The lead with an insulating resin film of the present disclosure includes a plate-shaped conductor having a rectangular shape on the upper and lower surfaces, an insulating resin film including a first insulating resin film disposed on the upper surface of the conductor and a second insulating resin film disposed on the lower surface of the conductor. When the conductor is viewed from above along the vertical direction of the upper surface, with the axis along two selected opposite sides as the X-axis and the axis perpendicular to the X-axis as the Y-axis, the conductor has conductor tapered portions at both ends along the X-axis, the thickness of which becomes thinner as it moves away from the first center, which is the center of the conductor along the X-axis. The first insulating resin film and the second insulating resin film are arranged to cover the conductor across the X-axis, having overlapping margin portions that protrude from both ends of the conductor, and not covering both ends of the conductor along the Y-axis. In the cross-section along the X-axis of the laminate obtained by laminating the insulating resin film and the conductor, the laminate has a resin tapered portion whose thickness becomes thinner as it moves away from the first center. An end of the conductor tapered portion close to the first center is defined as the first conductor end. When an end of the resin tapered portion close to the first center is defined as the first resin end and an end away from the first center is defined as the second resin end, the position of the first resin end along the X-axis is the same as the position of the first conductor end or closer to the first center than the position of the first conductor end. The position of the second resin end along the X-axis is farther from the first center than the end of the conductor along the X-axis.

Advantages of the Invention

[0008] According to the present disclosure, a lead with an insulating resin film having excellent adhesion to an exterior body can be provided.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3A

Figure 3B

Figure 4

Figure 5

Mode for Carrying Out the Invention

[0010] The mode for carrying out the invention will be described below.

[0011] [Description of Embodiments of the Present Disclosure] First, embodiments of the present disclosure will be listed and described. In the following description, the same or corresponding elements are denoted by the same reference numerals, and the same description thereof will not be repeated.

[0012] (1) A lead with an insulating resin film according to one aspect of the present disclosure includes a plate-like conductor having a rectangular shape on the upper and lower surfaces, an insulating resin film including a first insulating resin film disposed on the upper surface of the conductor and a second insulating resin film disposed on the lower surface of the conductor, and when the conductor is viewed from above along the vertical direction of the upper surface, with an axis along two selected opposing sides as the X-axis and an axis orthogonal to the X-axis as the Y-axis, the conductor has conductor tapered portions at both ends along the X-axis, the thickness of which decreases as it moves away from a first center that is the center of the conductor along the X-axis, the first insulating resin film and the second insulating resin film are disposed so as to cover the conductor across the conductor along the X-axis and have margin portions that protrude from both ends of the conductor and overlap, and do not cover both ends of the conductor along the Y-axis, in the cross-section along the X-axis of the laminate in which the insulating resin film and the conductor are laminated, the laminate has a resin tapered portion whose thickness decreases as it moves away from the first center. The end of the conductor taper portion near the first center is defined as the first conductor end, When the end of the resin taper portion near the first center is defined as the first resin end and the end away from the first center is defined as the second resin end, the position of the first resin end along the X-axis is the same as the position of the first conductor end or is closer to the first center than the position of the first conductor end, the position of the second resin end along the X-axis is farther from the first center than the end of the conductor along the X-axis.

[0013] By having conductor taper portions at both ends of the conductor, it is possible to prevent a gap from occurring between the exterior body of the battery and the insulating resin film near the margin portion. In particular, when the conductor is thickened, the effect of preventing the occurrence of a gap is significant.

[0014] By arranging the positions of the first resin end and the second resin end of the resin taper portion as described above, the length of the resin taper portion along the X-axis can be increased, and the slope of the outer surface of the resin taper portion can be made gentle. Therefore, when the lead with a resin film according to one aspect of the present disclosure is thermally welded to the exterior body, the resin of the exterior body is likely to be filled also in the resin taper portion, enhancing the adhesion to the exterior body and suppressing the generation of voids.

[0015] (2) In the above (1), the position of the second resin end along the X-axis may be farther from the first center than the second center, which is the center of the margin portion along the X-axis.

[0016] By setting the position of the second resin end along the X-axis to be farther from the first center of the conductor than the second center of the margin portion, the length of the resin taper portion along the X-axis can be made particularly long, and the slope of the resin taper portion can be made particularly gentle. Therefore, when the lead with a resin film according to one aspect of the present disclosure is thermally welded to the exterior body, the resin of the exterior body is likely to be filled also in the resin taper portion, enhancing the adhesion to the exterior body particularly and suppressing the generation of voids.

[0017] (3) In the above (1) or (2), the insulating resin film may have two or more layers.

[0018] By having the insulating resin film with two or more layers, it is possible to easily adjust the strength of the insulating resin film, the adhesion between the insulating resin film and the exterior body, and the adhesion between the insulating resin film and the conductor after thermally welding the exterior body to the insulating resin film.

[0019] (4) In any of the above (1) to (3), the thickness of the insulating resin film may be 100 μm or more.

[0020] By setting the thickness of the insulating resin film to 100 μm or more, it is possible to prevent a gap from occurring between the insulating resin film and the conductor.

[0021] (5) In any of the above (1) to (4), the length of the margin portion along the X-axis may be 5 mm or less.

[0022] By setting the length of the margin portion to 5 mm or less, the width for sandwiching the lead with the insulating resin film according to one aspect of the present disclosure, where the seal portion is a foreign object, can be shortened, and the sealing performance can be enhanced.

[0023] [Details of Embodiments of the Present Disclosure] A specific example of a lead with an insulating resin film according to an embodiment of the present disclosure (hereinafter referred to as "this embodiment") will be described below with reference to the drawings. Note that the present invention is not limited to these examples, and is indicated by the claims, and is intended to include all modifications within the meaning and scope equivalent to the claims.

[0024] In this specification, when explaining members such as the first insulating resin film and the second insulating resin film, the first, second, etc. may be added to the member names for description. The first, second, etc. are merely described to identify each member and prevent confusion during explanation, and do not represent arrangement, priority, etc. Therefore, when there is no particular risk of confusion or when showing them collectively, they can be simply expressed as an insulating resin film, for example. [Lead with Insulating Resin Film] FIG. 1 shows an explanatory diagram of a configuration example when the lead with an insulating resin film (hereinafter also referred to as "lead") of the present embodiment is applied to a battery. FIG. 2 is an explanatory diagram of the lead with an insulating resin film of the present embodiment when viewed vertically above the upper surface of the conductor. FIG. 3A shows a cross-sectional view taken along line A-A' of FIG. 1. FIG. 3B shows another configuration example corresponding to the cross-sectional view taken along line A-A' of FIG. 1. FIG. 4 shows a cross-sectional view taken along line B-B' of FIG. 2. Since FIG. 3B is a modified example of the lead with an insulating resin film of the present embodiment, it will be mainly described with reference to FIGS. 1, 2, 3A, and 4, and FIG. 3B will be used as necessary.

[0025] The Z-axis in FIGS. 1, 2, 3A, 3B, 4, and 5 is the axis along the thickness of the conductor and the insulating resin film that the lead of the present embodiment has.

[0026] The lead 13 of the present embodiment can be applied to a battery. Therefore, after explaining the battery to which the lead 13 of the present embodiment can be applied, the details of the lead 13 of the present embodiment will be explained. (1) About the battery A configuration example of the battery to which the lead 13 of the present embodiment is applied is shown in FIG. 1. As shown in FIG. 1, the battery 10 can include an exterior body 11, an electrode laminate 12 in which a positive electrode, a separator, and a negative electrode are laminated and impregnated with an electrolytic solution, and a lead 13 according to one aspect of the present disclosure connected to the electrode laminate 12. (Exterior body) The exterior body 11 is a container that houses and seals the electrode laminate 12 and the electrolytic solution. The exterior body 11 can have at least one resin layer on the surface facing the electrode laminate 12 so that heat welding can be performed.

[0027] As shown by the dashed line in FIG. 1, a seal portion 110 is formed at the periphery of the exterior body 11, and the electrode laminate 12 and the electrolytic solution are sealed by the seal portion 110. (2) Regarding the lead Each member of the lead 13 in the present embodiment will be described. (2-1) Conductor The conductor 14 is a member for connecting the electrode laminate 12 disposed inside the exterior body 11 and the devices disposed outside the exterior body 11. The conductor 14 can have a plate shape, and the upper surface 141 and the lower surface 142 (see FIG. 3A) have a rectangular shape. As shown in FIG. 2, the upper surface 141 of the conductor 14 has two opposite sides 21 and 22 and two sides 23 and 24 that intersect the sides 21 and 22. However, the rectangular shape does not mean a geometrically exact shape, and the conductor 14 may have a shape with rounded corners.

[0028] In the following description, when viewing the conductor 14 from above along the vertical direction of the upper surface 141, the axis along the two selected opposite sides 21 and 22 is defined as the X-axis. Also, the axis orthogonal to the X-axis is defined as the Y-axis.

[0029] FIG. 4 shows a cross-sectional view along the X-axis, which is a cross-sectional view of the laminate 400 in which the insulating resin film 15 and the conductor 14 are laminated, taken along the line B-B' in FIG. 2. As shown in FIG. 4, the conductor 14 can have conductor tapered portions 14B at both ends 14C along the X-axis, the thickness of which decreases as it moves away from the first center C1, which is the center of the conductor 14 along the X-axis. The first center C1 means the center between both ends 14C of the conductor 14 along the X-axis.

[0030] By the conductor 14 having the conductor tapered portions 14B at both ends 14C, it is possible to prevent a gap from occurring between the exterior body 11 of the battery and the insulating resin film 15 near the margin portion 40. Particularly when the conductor 14 is thickened, the effect of preventing the gap from occurring is significant.

[0031] In FIG. 4, the conductor taper portion 14B of the conductor 14 has a shape that is symmetric about the left and right ends 14C of the conductor 14. However, the present invention is not limited to such a form, and the gradients of the conductor taper portions 14B on the left and right, the shape of the taper, and the lengths along the X-axis may be different. Further, the gradients of the conductor taper portions 14B, the shape of the taper, the lengths along the X-axis, etc. may be different between the upper surface 141 and the lower surface 142 of the conductor 14, and either the upper surface 141 or the lower surface 142 may be a flat surface. Furthermore, in FIG. 4, the shapes of both ends 14C of the conductor 14 are straight lines (planes), but they may be curves such as arc shapes.

[0032] The conductor 14 can have a flat portion 14A with a constant thickness in a region including the first center C1 sandwiched by the conductor taper portions 14B. The flat portion 14A does not necessarily have a strictly flat outer surface, and the thickness may vary within the range of manufacturing tolerances and may include portions that are not flat.

[0033] In the following description, the end of the conductor taper portion 14B close to the first center C1 is defined as the first conductor end 43. The first conductor end 43 is the connection portion between the flat portion 14A and the conductor taper portion 14B. The first conductor end 43 can be defined as the point where the thickness begins to become thinner than the thickness of the flat portion 14A, paying attention to the change in the thickness of the conductor 14.

[0034] The material of the conductor 14 is not particularly limited, and for example, various materials used for lead conductors can be used. Examples of the material of the conductor 14 include metal materials such as aluminum, titanium, nickel, copper, aluminum alloys, titanium alloys, nickel alloys, copper alloys, and materials obtained by plating these metal materials with nickel, gold, etc. (2-2) Insulating resin film As shown in FIGS. 3A and 4, the insulating resin film 15 includes a first insulating resin film 151 disposed on the upper surface 141 of the conductor 14 and a second insulating resin film 152 disposed on the lower surface 142 of the conductor 14. As shown in FIGS. 2 and 3A, on the upper surface 141 and the lower surface 142, the first insulating resin film 151 and the second insulating resin film 152 are arranged so as not to cover and to expose both end portions of the conductor 14 along the Y-axis, that is, both end portions including sides 21 and 22. Therefore, on the upper surface 141 and the lower surface 142 of the conductor 14, the first insulating resin film 151 and the second insulating resin film 152 are arranged to cover the conductor 14 across the X-axis at an intermediate portion which is a portion other than both end portions of the conductor 14 along the Y-axis.

[0035] The upper surface 141 and the lower surface 142 of the conductor 14 mean the surfaces facing the exterior body 11 of the battery 10 when manufacturing the battery 10.

[0036] Among the conductor 14, both end portions along the Y-axis mean, as shown in FIG. 2, a first end portion region 25 including side 21 and a second end portion region 26 including side 22. The intermediate portion is a portion located between the first end portion region 25 and the second end portion region 26.

[0037] The first end portion region 25 is, for example, a portion exposed outside the exterior body 11 when the lead 13 is applied to the battery, and its size can be selected so as to be connectable to external devices. Further, the second end portion region 26 is, for example, a portion located inside the exterior body 11 and connected to the electrode laminate 12 when the lead 13 is applied to the battery, and its size can be selected so as to be connectable to the electrode laminate 12. The first end portion region 25 and the second end portion region 26 may have the same size such as the same area, or may be different.

[0038] Therefore, the length L14 of the conductor 14 along the Y-axis is longer than the length L15 of the insulating resin film 15. Also, the length W15 of the insulating resin film 15 is longer than the length W14 of the conductor 14 along the X-axis.

[0039] As shown in FIG. 4, the first insulating resin film 151 and the second insulating resin film 152 are arranged so as to have a margin portion 40 that protrudes from both end portions 14C of the conductor along the X-axis and overlaps. The margin portion 40 is a portion located outside the conductor 14 rather than both end portions 14C of the conductor 14, and the first insulating resin film 151 and the second insulating resin film 152 are in direct contact with each other and are bonded together.

[0040] In the cross-section along the X-axis of the laminate 400 in which the insulating resin film 15 and the conductor 14 are laminated, as shown in FIG. 4, the laminate 400 has a resin tapered portion 15B whose thickness decreases as it moves away from the first center C1.

[0041] As shown in FIG. 4, in the cross-section along the X-axis, the laminate 400 has a first flat portion 15A including the first center C1 of the conductor 14 and a second flat portion 15C located at both end portions 15D along the X-axis. The resin tapered portion 15B is disposed between the first flat portion 15A and the second flat portion 15C so as to connect the first flat portion 15A and the second flat portion 15C. The first flat portion 15A and the second flat portion 15C do not necessarily have a flat outer surface in a strict sense, and may include portions where the thickness changes within the range of manufacturing tolerances and is not flat.

[0042] In the following description, the end portion of the resin tapered portion 15B close to the first center C1 is referred to as the first resin end portion 41. Also, the end portion of the resin tapered portion 15B farther from the first center C1 than the first resin end portion 41 is referred to as the second resin end portion 42.

[0043] The lead 13 of this embodiment adheres to the seal portion 110 (see FIG. 1) at the insulating resin film 15 portion.

[0044] The inventor of the present invention examined the cause of the occurrence of a gap between the exterior body 11 and the insulating resin film 15 when the lead with the insulating resin film and the exterior body are welded.

[0045] As a result, as shown in FIG. 5 which is a cross section along the X-axis when the conventional lead 53 is heat-welded to the exterior body 11, it was confirmed that the void 51 mainly occurred in the resin tapered portion 15B of the insulating resin film 15. In the conventional lead 53, the position of the first resin end portion 41 along the X-axis was farther from the first center C1 than the position of the first conductor end portion 43, the length of the resin tapered portion 15B along the X-axis was short, and the inclination was steep. For this reason, it is considered that the resin of the exterior body 11 could not be filled in the vicinity of the resin tapered portion 15B and the void 51 was generated.

[0046] Therefore, in the lead 13 of the present embodiment, the position of the first resin end portion 41 along the X-axis is arranged at the same position as the position of the first conductor end portion 43 or at a position closer to the first center C1 than the position of the first conductor end portion 43. Further, the position of the second resin end portion 42 along the X-axis is arranged at a position farther from the first center C1 than the end portion 14C of the conductor 14 along the X-axis.

[0047] As is clear from FIG. 4, in any cross section of the laminate 400, the first resin end portion 41 and the second resin end portion 42 can exist at a maximum of four locations in total, two locations on the upper surface 141 of the conductor 14 and two locations on the lower surface 142 of the conductor 14, respectively. In any cross section of the laminate 400, regarding the first resin end portion 41 and the second resin end portion 42, at least one of the four locations may be arranged as described above, but all four locations may be arranged as described above.

[0048] By arranging the positions of the first resin end portion 41 and the second resin end portion 42 of the resin tapered portion 15B as described above, the length of the resin tapered portion 15B along the X-axis can be increased, and the inclination of the outer surface of the resin tapered portion 15B can be made gentle. For this reason, when the lead 13 of the present embodiment is heat-welded to the exterior body 11, the resin of the exterior body 11 is also easily filled in the resin tapered portion 15B, the adhesion with the exterior body 11 can be enhanced, and the generation of voids can be suppressed.

[0049] In addition, in this specification, the lead 13 having excellent adhesion to the exterior body 11 means a lead 13 that can suppress the generation of a gap between the exterior body 11 and the insulating resin film 15 when the lead 13 is thermally welded to the exterior body 11.

[0050] The position of the second resin end portion 42 along the X-axis may be arranged at a position farther from the first center C1 of the conductor 14 than the second center C2 that is the center of the margin portion 40 along the X-axis.

[0051] By setting the position of the second resin end portion 42 along the X-axis to a position farther from the first center C1 of the conductor 14 than the second center C2 of the margin portion 40, the length of the resin taper portion 15B along the X-axis can be made particularly long, and the inclination of the resin taper portion 15B can be made particularly gentle. Therefore, when the lead 13 of the present embodiment is thermally welded to the exterior body 11, the resin of the exterior body 11 is likely to be filled also in the resin taper portion 15B, the adhesion to the exterior body 11 can be particularly enhanced, and the generation of a gap can be suppressed.

[0052] The margin portion 40 is a region between the end portion 14C of the conductor 14 and the end portion 15D of the insulating resin film 15. The second center C2 of the margin portion 40 is a position where L401 = L402 when the distance from the end portion 15D of the insulating resin film 15 along the X-axis to the second center C2 is L401 and the distance from the end portion 14C of the conductor 14 to the second center C2 is L402. When the length of the margin portion 40 along the X-axis is L40, L40 = L401 + L402.

[0053] The shape of the resin taper portion 15B of the insulating resin film 15, for example, the positions of the first resin end portion 41 and the second resin end portion 42 can be easily adjusted by selecting, for example, the shape of the mold used when welding the insulating resin film 15 to the conductor 14, the welding conditions, and the like.

[0054] The length L40 of the margin portion 40 along the X-axis is not particularly limited, but can be, for example, 5 mm or less. By setting the length L40 of the margin portion 40 to 5 mm or less, the width of the seal portion 110 sandwiching the lead 13 that is a foreign object can be shortened, and the sealing property can be enhanced.

[0055] The lower limit value of the length L40 along the X-axis of the margin portion 40 is not particularly limited either, but can be, for example, 1 mm or more. By setting the length L40 along the X-axis of the margin portion 40 to 1 mm or more, the adhesion between the first insulating resin film 151 and the second insulating resin film 152 can be enhanced, and it is possible to particularly suppress the occurrence of a gap between the insulating resin film 15 and the conductor 14.

[0056] The length along the X-axis of the margin portion 40 can be, for example, 1 mm or more and 5 mm or less as described above.

[0057] The insulating resin film 15 is a layer for enabling thermal welding with the exterior body 11 when applied to a battery. Therefore, the insulating resin film 15 can contain, for example, a thermoplastic resin as the resin. As the thermoplastic resin, one or more selected from, for example, polyolefin resins, polyester resins, polystyrene resins, polyvinyl chloride resins, etc. can be used. Examples of the polyolefin resin include polyethylene, polypropylene, acid-modified polyolefin resins such as acid-modified polyethylene and acid-modified polypropylene. Examples of the polyester resin include polyethylene terephthalate resin. Examples of the acid-modified polyolefin include maleic anhydride-modified polyolefin.

[0058] The insulating resin film 15 can also have two or more layers as shown in FIGS. 3A and 3B. The insulating resin film 15 can have a base layer 31 and a surface layer 32 as shown in FIG. 3A. The insulating resin film 15 can have a base layer 31, an intermediate layer 33, and a surface layer 32 as shown in FIG. 3B. When the insulating resin film 15 has three layers, for example, the layers can be functionally separated such that one layer adheres to the conductor 14, one layer adheres to the exterior body 11, and one layer is resistant to being crushed and maintains strength when the lead 13 is welded to the exterior body 11.

[0059] Therefore, materials can be selected for each layer according to the intended functions and the like. For the layer adhered to the conductor 14, acid-modified polypropylene is preferable in terms of adhesion. The layer adhered to the exterior body 11 is preferably made of a material having good adhesiveness with the material of the exterior body 11.

[0060] Since the insulating resin film has two or more layers, after thermally welding the exterior body to the insulating resin film, the strength of the insulating resin film, the adhesion between the insulating resin film and the exterior body, and the adhesion between the insulating resin film and the conductor can be easily adjusted.

[0061] The thickness T15 of the insulating resin film 15 is not particularly limited either. For example, the thickness T15 of the insulating resin film 15 can be 100 μm or more.

[0062] By setting the thickness T15 of the insulating resin film 15 to 100 μm or more, it is possible to prevent a gap from occurring between the insulating resin film 15 and the conductor 14.

[0063] The thickness T15 of the insulating resin film 15 can be, for example, 100 μm or more and 300 μm or less. Note that the thickness T15 may be different or the same between the first insulating resin film 151 and the second insulating resin film 152. Also, when the insulating resin film 15 has a plurality of layers, the total thickness of the plurality of layers becomes the above thickness T15.

[0064] By setting the thickness T15 of the insulating resin film 15 to 300 μm or less, it is possible to particularly prevent a gap from occurring between the insulating resin film 15 and the exterior body 11 after thermally welding the exterior body 11.

Examples

[0065] Specific examples will be given below for explanation, but the present invention is not limited to these examples.

[0066] The leads and batteries in each experimental example will be described below.

[0067] Experimental Example 1 is an example, and Experimental Example 2 is a comparative example. In both Experimental Example 1 and Experimental Example 2, the first insulating resin film 151 and the second insulating resin film 152 have the same configuration. [Experimental Example 1] The lead 13 shown in FIGS. 2, 3A, and 4 was produced, and the exterior body 11 was heat-sealed to the lead 13. The insulating resin film 15 has two layers, a base layer 31 containing maleic anhydride-modified polypropylene and a surface layer 32 containing polypropylene, starting from a position close to the conductor 14.

[0068] When forming the insulating resin film 15 on the upper surface 141 and the lower surface 142 of the conductor 14, the shape of the mold and the heating conditions were selected so as to obtain the cross-sectional shape shown in FIG. 4.

[0069] Therefore, in the laminate 400 of the lead 13 of this experimental example, in the cross-section along the X-axis, the position of the first resin end 41 along the X-axis is the same as the position of the first conductor end 43 or closer to the first center C1 than the position of the first conductor end 43. Also, the position of the second resin end 42 along the X-axis is farther from the first center C1 than the second center C2.

[0070] As shown in FIG. 4, the first resin end 41 and the second resin end 42 each exist at two locations on the upper surface 141 of the conductor 14 and two locations on the lower surface 142 of the conductor 14, for a total of four locations. In this experimental example, the above arrangement was made for all four locations.

[0071] The length L40 of the margin portion 40 was set to 5 mm, and the thickness T15 of the insulating resin film 15, that is, the first insulating resin film 151 and the second insulating resin film 152, was set to 100 μm.

[0072] As the exterior body 11, a laminate film was used in which the first resin layer 111 and the second resin layer 113 are polypropylene films and the metal layer 112 is aluminum foil.

[0073] The positions of the lead 13 and the exterior body 11 were adjusted so that a part of the insulating resin film 15 along the Y-axis was covered by the exterior body 11, and heat welding was performed to form the seal portion 110. Two cases were considered: one with a heat welding time of 1.5 seconds and the other with a heat welding time of 3.0 seconds. In each case, heat welding was performed 10 times, and 10 samples were produced. The heat welding conditions other than the time were the same.

[0074] The cross-section of the insulating resin film 15 along the plane passing through the X-axis was observed. The evaluation results are shown in Table 1. In Experimental Example 1, even when the heat welding time was shortened, no gap was observed between the exterior body 11 and the insulating resin film 15, and it was observed that the two members were in close contact. [Experimental Example 2] Regarding the lead 13, the lead 53 was produced under the same conditions as in Experimental Example 1 except that it was formed in the form shown in FIG. 5, and the exterior body 11 was heat welded to the lead 53, and the cross-sectional shape was evaluated.

[0075] Therefore, in the laminate 500 of the lead 53 in this experimental example, in the cross-section along the X-axis, the position of the first resin end portion 41 along the X-axis is farther from the first center C1 than the position of the first conductor end portion 43. Also, the position of the second resin end portion 42 along the X-axis, although it is farther from the first center C1 than the end portion 14C of the conductor 14, is closer to the first center C1 than the second center C2. The evaluation results are shown in Table 1.

[0076] When the cross-section of the insulating resin film 15 along the plane passing through the X-axis was confirmed at a plurality of locations, as shown in FIG. 5, voids 51 were sometimes observed in the resin tapered portion 15B and the second flat portion 15C.

[0077]

Table 1

Explanation of Signs

[0078] 10 Battery 11 Exterior body 110 Seal portion 111 First resin layer 112 Metal layer 113 Second resin layer 12 Electrode laminate 13 Lead (lead with insulating resin film) 14 Conductor 141 Upper surface 142 Lower surface 14A Flat part 14B Conductor taper part 14C End part 15 Insulating resin film T15 Thickness 151 First insulating resin film 152 Second insulating resin film 15A First flat part 15B Resin taper part 15C Second flat part 15D End part 21 Side 22 Side 23 Side 24 Side 25 First end region 26 Second end region L14 Length W14 Length L15 Length W15 Length 31 Underlayer 32 Surface layer 33 Intermediate layer 400 Laminate 40 Margin part 41 First resin end 42 Second resin end 43 First conductor end C1 First center C2 Second center L40 Length L401 Length L402 Length 500 Laminate 51 Void 53 Lead (lead with insulating resin film) X X-axis Y Y-axis Z Z-axis

Claims

1. A plate-shaped conductor having a rectangular shape on its upper and lower surfaces, and an insulating resin film including a first insulating resin film disposed on the upper surface of the conductor and a second insulating resin film disposed on the lower surface of the conductor. When the conductor is viewed from above along the vertical direction of the upper surface, with the axis along two selected opposing sides as the X-axis and the axis orthogonal to the X-axis as the Y-axis, The conductor has conductor tapered portions at both ends along the X-axis, the thickness of which becomes thinner as it moves away from a first center that is the center of the conductor along the X-axis. The first insulating resin film and the second insulating resin film are arranged so as to cover the conductor across the X-axis, have margin portions that protrude from both ends of the conductor and overlap, and do not cover both ends of the conductor along the Y-axis. In a cross-section of the laminate obtained by laminating the insulating resin film and the conductor along the X-axis, the laminate has a resin tapered portion whose thickness becomes thinner as it moves away from the first center. Taking the end of the conductor tapered portion closer to the first center as the first conductor end, When taking the end of the resin tapered portion closer to the first center as the first resin end and the end away from the first center as the second resin end, The position of the first resin end along the X-axis is the same as the position of the first conductor end or is closer to the first center than the position of the first conductor end. The position of the second resin end along the X-axis is at a position farther from the first center than the end of the conductor along the X-axis. A lead with an insulating resin film.

2. The lead with an insulating resin film according to Claim 1, wherein the position of the second resin end along the X-axis is at a position farther from the first center than a second center that is the center of the margin portion along the X-axis.

3. The lead with an insulating resin film according to Claim 1 or Claim 2, wherein the insulating resin film has two or more layers.

4. The lead with an insulating resin film according to Claim 1 or Claim 2, wherein the thickness of the insulating resin film is 100 μm or more.

5. The lead with an insulating resin film according to Claim 1 or Claim 2, wherein the length of the margin portion along the X-axis is 5 mm or less. ​

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