Lead with insulating resin film

Abstract

To provide a lead with an insulating resin film with which, when applied to a battery, it is possible to eject a gas generated in a region sealed by the outer packaging of the battery to the outside of the region sealed by the outer packaging.SOLUTION: Provided is a lead with an insulating resin film comprising a conductor and an insulating resin film, wherein, when an axis extending along two sides facing each other is defined as an axis X and an axis crossing the axis X is defined as an axis Y with the conductor viewed from above, the insulating resin film is disposed so as to cover the conductor crossing it along the axis X and not to cover both ends of the conductor that are along the axis Y so as to extend off both ends of the conductor and overlap. The insulating resin film has a first layer being in contact with the conductor, and a second layer. The second layer includes a base resin composed primarily of polypropylene, and one or more kinds of additive component selected from a rubber component and an elastomer component. The melting point of the base resin is 110°C to 130°C inclusive, and the softening point of the additive component is 130°C or below. The second layer contains 10 mass% to 40 mass% inclusive of the additive component.SELECTED DRAWING: Figure 3A

Description

Technical Field

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

Background Art

[0002] Patent Document 1 discloses a power storage device including at least a power storage device element having a positive electrode, a negative electrode, and an electrolyte, an exterior material for a power storage device that seals the power storage device element, and metal terminals that are electrically connected to each of the positive electrode and the negative electrode and protrude outside the exterior material for the power storage device, wherein an adhesive film for a metal terminal is interposed between the metal terminal and the exterior material for the power storage device.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Inside the exterior of various batteries, the electrolyte or the like generates heat due to a reaction, the battery becomes hot beyond the usable temperature, and gas may be generated. From the viewpoint of avoiding battery damage or the like, when gas is generated within the region sealed by the exterior, it is required to be configured such that the gas can be discharged outside the region sealed by the exterior.

[0005] An object of the present disclosure is to provide a lead with an insulating resin film capable of discharging gas generated within a region sealed by the exterior of a battery outside the region sealed by the exterior when applied to a battery.

Means for Solving the Problems

[0006] 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 orthogonal to the X-axis as the Y-axis, the first insulating resin film and the second insulating resin film are arranged to cover the conductor across the conductor along the X-axis, protrude from both ends of the conductor and overlap, and do not cover both ends of the conductor along the Y-axis, the first insulating resin film and the second insulating resin film each include a plurality of layers with different compositions, the first insulating resin film and the second insulating resin film each have a first layer in contact with the conductor and a second layer different from the first layer, the second layer includes a base resin mainly composed of polypropylene and one or more additive components selected from a rubber component and an elastomer component, the melting point of the base resin is 110°C or higher and 130°C or lower, and the softening point of the additive component is 130°C or lower, the second layer contains the additive component at a ratio of 10% by mass or more and 40% by mass or less.

Advantages of the Invention

[0007] According to the present disclosure, when applied to a battery, it is possible to provide a lead with an insulating resin film that can discharge gas generated within the region sealed by the battery enclosure to the outside of the region sealed by the enclosure.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3A

Figure 3B

Figure 4

Figure 5

Figure 6

Mode for Carrying Out the Invention

[0009] The mode for carrying out the invention will be described below.

[0010] [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.

[0011] (1) The lead with an insulating resin film according to one aspect 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 an axis along two selected opposite sides as the X-axis and an axis orthogonal to the X-axis as the Y-axis, the first insulating resin film and the second insulating resin film are arranged to cover the conductor across the conductor along the X-axis, protrude from both ends of the conductor and overlap, and do not cover both ends of the conductor along the Y-axis, the first insulating resin film and the second insulating resin film each include a plurality of layers having different compositions, The first insulating resin film and the second insulating resin film each have a first layer in contact with the conductor and a second layer different from the first layer. The second layer contains a base resin mainly composed of polypropylene and one or more additive components selected from a rubber component and an elastomer component. The melting point of the base resin is 110°C or higher and 130°C or lower, and the softening point of the additive component is 130°C or lower. The second layer contains the additive component in a proportion of 10% by mass or more and 40% by mass or less.

[0012] In this specification, a lead with an insulating resin film may sometimes be simply referred to as a "lead".

[0013] By setting the melting point of the base resin contained in the second layer to 130°C or lower, when the battery becomes hot beyond the usable temperature, the adhesion between the second layer and other members in contact with the second layer can be reduced. Therefore, even if gas is generated within the region sealed by the exterior body when the battery becomes hot beyond the usable temperature, the gas can be discharged outside the region sealed by the exterior body.

[0014] In this specification, other members in contact with the second layer mean layers other than the second layer contained in the insulating resin film in contact with the second layer, or the exterior body when the second layer is in contact with the exterior body.

[0015] Also, by setting the melting point of the base resin to 110°C or higher, it is possible to prevent a decrease in the adhesion between the second layer and other members in contact with the second layer in a temperature region where almost no gas is generated within the region sealed by the exterior body, and the electrode laminate and the electrolyte can be sealed.

[0016] When the second layer contains an additive component, when a force is applied to the insulating resin film so as to peel the lead from the exterior body, the stress applied to the insulating resin film is relaxed, and the adhesion between the second layer and other members in contact with the second layer can be enhanced. Further, by setting the softening point of the additive component to 130° C. or lower, when the battery becomes high temperature exceeding the usable temperature, the gas generated in the region sealed by the exterior body can be configured to be discharged outside the region sealed by the exterior body.

[0017] By setting the content ratio of the additive component in the second layer to 10% by mass or more, when a force is applied to the insulating resin film so as to peel the lead from the exterior body, the stress applied to the insulating resin film is relaxed, and the adhesion between the second layer and other members in contact with the second layer can be enhanced. Further, by setting the content ratio of the additive component in the second layer to 40% by mass or less, a decrease in the mechanical strength of the insulating resin film can be suppressed.

[0018] (2) In the above (1), the base resin of the second layer may be crosslinked.

[0019] When manufacturing the battery, the exterior body is disposed on the upper and lower surfaces of the lead, and the lead can be thermally welded to the exterior body by heating while applying pressure to the region including the portion where the insulating resin film of the lead and the exterior body overlap. By crosslinking the base resin contained in the second layer, when thermally welding the lead to the exterior body, it is possible to prevent the insulating resin film from being crushed. For this reason, the shape of the insulating resin film can be stabilized, and the adhesion of the lead to the exterior body can also be enhanced.

[0020] [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 "the present embodiment") will be described below with reference to the drawings. Note that the present invention is not limited to these examples, and is shown by the claims, and is intended to include all modifications within the meaning and scope equivalent to the claims.

[0021] In this specification, when describing members such as the first insulating resin film and the second insulating resin film, the terms "first", "second", etc. may be added to the member names for explanation. The terms "first", "second", etc. are only 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 presenting 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 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. Since FIG. 3B is a modified example of the lead with an insulating resin film of the present embodiment, the explanation will mainly be made using FIGS. 1, 2, and 3A, and FIG. 3B will be used as needed.

[0022] The Z-axis in FIGS. 1, 2, 3A, and 3B is the axis along the thickness of the conductor and the insulating resin film that the lead of the present embodiment has.

[0023] 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.

[0024] 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. The region surrounded by the seal portion 110 is the region sealed by the exterior body 11. (2) Regarding the lead The conductor 14 and the insulating resin film 15, which are the members of the lead 13 of 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 opposing sides, side 21 and side 22, and sides 23 and 24 that intersect side 21 and side 22. However, the rectangular shape does not mean a geometrically exact shape, and the conductor 14 may have a shape with rounded corners.

[0025] 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 opposing sides, side 21 and side 22, is defined as the X-axis. Also, the axis orthogonal to the X-axis is defined as the Y-axis.

[0026] The material of the conductor 14 is not particularly limited, and for example, various materials used for the conductors of leads 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 FIG. 3A, 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 but to expose both end portions of the conductor 14 along the Y axis, that is, both end portions including the side 21 and the side 22. For this reason, 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 so as 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.

[0027] 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.

[0028] Among the conductor 14, both end portions along the Y axis mean a first end portion region 25 including the side 21 and a second end portion region 26 including the side 22 as shown in FIG. 2. The intermediate portion is a portion located between the first end portion region 25 and the second end portion region 26.

[0029] 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 area, or may be different.

[0030] For this reason, 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.

[0031] As shown in Fig. 2, the first insulating resin film 151 and the second insulating resin film 152 are arranged so as to protrude from both ends 14C of the conductor along the X axis and overlap each other. In the portion protruding from the conductor 14, the first insulating resin film 151 and the second insulating resin film 152 are in direct contact with each other and are bonded together.

[0032] The lead 13 of the present embodiment is in close contact with the seal portion 110 (see Fig. 1) at the insulating resin film 15 portion.

[0033] The inventor of the present invention has considered a lead 13 that can discharge gas outside the region sealed by the exterior body 11 when the battery becomes hot beyond the usable temperature and gas or the like is generated inside the region where the electrode laminate 12 and the like are arranged and sealed by the exterior body 11 of the battery 10. By configuring the second layer 32 (see Fig. 3A) in the insulating resin film 15 included in the lead 13 in a predetermined configuration, it has been found that when gas is generated in the region sealed by the exterior body 11, the adhesive force between the second layer 32 and other members in contact with the second layer 32 decreases. For this reason, it has been found that when gas is generated in the region sealed by the exterior body 11, the gas can be discharged outside the region sealed by the exterior body 11, and the present invention has been completed. (2-2-1) Second layer The first insulating resin film 151 and the second insulating resin film 152, which are the insulating resin films 15 included in the lead 13 of the present embodiment, can each include a plurality of layers having different compositions. The first insulating resin film 151 and the second insulating resin film 152 each have a first layer 31 in contact with the conductor 14 and a second layer 32 different from the first layer 31. The second layer 32 can include a base resin mainly composed of polypropylene and one or more additive components selected from a rubber component and an elastomer component. The phrase "mainly composed of polypropylene" means that it is contained in the largest mass ratio among the components contained in the base resin. (Base resin) The melting point of the base resin contained in the second layer 32 may be 110°C or higher and 130°C or lower, or may be 120°C or higher and 130°C or lower. By setting the melting point of the base resin contained in the second layer 32 to 130°C or lower, when the battery becomes hot beyond the usable temperature, the adhesion between the second layer 32 and other members in contact with the second layer 32 can be reduced. Therefore, when the battery becomes hot beyond the usable temperature, even if gas is generated within the region sealed by the exterior body 11, the gas can be discharged outside the region sealed by the exterior body 11.

[0034] Also, by setting the melting point of the base resin to 110°C or higher, it is possible to prevent a decrease in the adhesion between the second layer and other members in contact with the second layer in a temperature range where almost no gas is generated within the region sealed by the exterior body, and the electrode laminate and the electrolyte can be sealed.

[0035] The base resin contained in the second layer 32 may be composed only of polypropylene, or may contain, in addition to polypropylene, a resin capable of setting the melting point of the base resin within the above temperature range. As the polypropylene, one or more selected from polypropylene homopolymers, block copolymers, and random copolymers can be used.

[0036] A polypropylene homopolymer is a polymer composed only of propylene.

[0037] A polypropylene block copolymer is a copolymer having a polymer block composed of propylene and a polymer block composed of another α-olefin other than propylene.

[0038] A polypropylene random copolymer is a random copolymer of propylene and another α-olefin other than propylene. Examples of the other α-olefin other than propylene include ethylene.

[0039] Examples of resins other than polypropylene that can contain the base resin include one or more selected from polystyrene, polyvinyl alcohol, polyvinyl acetate, acrylic resins, ABS resins (acrylonitrile-butadiene-styrene copolymer synthetic resins), polyester resins, fluorine-based resins, and the like.

[0040] The base resin contained in the second layer 32 may be crosslinked.

[0041] When manufacturing the battery 10, the exterior body 11 is arranged on the upper and lower surfaces of the lead 13 of the present embodiment, and the lead 13 can be heat-sealed to the exterior body 11 by heating while applying pressure to the region including the portion where the insulating resin film 15 of the lead 13 and the exterior body 11 overlap. Since the base resin contained in the second layer 32 is crosslinked, it is possible to prevent the insulating resin film 15 from being crushed when the lead 13 is heat-sealed to the exterior body 11. Therefore, the shape of the insulating resin film 15 can be stabilized, and the adhesion of the lead 13 to the exterior body 11 can also be enhanced. (Additive component) Since the second layer 32 contains an additive component, when a force is applied to the insulating resin film 15 so as to peel the lead 13 from the exterior body 11, the stress applied to the insulating resin film 15 is relaxed, and the adhesive force between the second layer 32 and other members in contact with the second layer 32 can be enhanced.

[0042] The additive component contained in the second layer 32 is not particularly limited, but the softening point of the additive component can be 130°C or lower. By setting the softening point of the additive component to 130°C or lower, when the battery becomes hot beyond the usable temperature, the gas generated in the region sealed by the exterior body 11 can be configured to be discharged outside the region sealed by the exterior body 11. The lower limit value of the softening point of the additive component is not particularly limited, but it may be, for example, 35°C or higher, or 40°C or higher.

[0043] The second layer 32 may contain an additive component in a proportion of 10% by mass or more and 40% by mass or less. By setting the content ratio of the additive component in the second layer 32 to 10% by mass or more, when a force is applied to the insulating resin film 15 to peel the lead 13 from the exterior body 11, the stress applied to the insulating resin film 15 is relaxed. And the adhesive force between the second layer 32 and another member in contact with the second layer 32 can be enhanced. Also, by setting the content ratio of the additive component in the second layer 32 to 40% by mass or less, a decrease in the mechanical strength of the insulating resin film 15 can be suppressed.

[0044] The additive component contained in the second layer 32 is not particularly limited, and the type and blending ratio of the additive component contained can be adjusted so that the softening point of the additive component is 130°C or lower. Examples of the additive component contained in the second layer 32 include one or more selected from ethylene propylene rubber, butyl rubber, ethylene propylene-diene rubber, styrene-butadiene rubber, urethane rubber, silicone rubber, natural rubber, acrylic rubber, and the like.

[0045] The additive component contained in the second layer 32 may be composed of only one type of additive component, or may be a mixture of two or more types of additive components. (2-2-2) The first layer, the third layer The insulating resin film 15 may also include layers other than the second layer 32.

[0046] The first insulating resin film 151 and the second insulating resin film 152, which are the insulating resin film 15, may each include a plurality of two or more layers as shown in FIGS. 3A and 3B.

[0047] As shown in FIG. 3A, the first insulating resin film 151 and the second insulating resin film 152 may each be composed of only two layers, namely the first layer 31 and the second layer 32.

[0048] Since the first insulating resin film 151 and the second insulating resin film 152 are each composed of only two layers, the number of steps in manufacturing the insulating resin film 15 and the lead 13 can be suppressed, and productivity can be enhanced.

[0049] As shown in FIG. 3B, the first insulating resin film 151 and the second insulating resin film 152 may each be composed of only three layers, namely, the first layer 31, the third layer 33, and the second layer 32. In FIG. 3B, they are arranged in the order of the first layer 31, the third layer 33, and the second layer 32 from the position close to the conductor 14, and the second layer 32 is in contact with the exterior body 11, but the present invention is not limited to such a form. For example, they may be arranged in the order of the first layer 31, the second layer 32, and the third layer 33 from the position close to the conductor 14, and the third layer 33, which is a layer other than the second layer 32, may be arranged in contact with the exterior body 11.

[0050] FIGS. 3A and 3B are merely illustrative, and the first insulating resin film 151 and the second insulating resin film 152 may each have any number of layers of two or more.

[0051] When the insulating resin film 15 has a plurality of layers, functional separation can also be achieved for each layer. When the insulating resin film 15 includes three layers, for example, functional separation can also be achieved, such as a layer that adheres to the conductor 14, a layer that adheres to the exterior body 11, and a layer that is not easily crushed when the lead 13 is welded to the exterior body 11 and maintains mechanical strength.

[0052] When the insulating resin film 15 includes a plurality of layers, the layers other than the second layer 32 can also contain resin. The layers other than the second layer 32 of 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.

[0053] Each layer of the insulating resin film 15 can have a material selected according to the intended function and the like. For example, a layer that adheres to the conductor 14 is preferably acid-modified polypropylene in terms of adhesion.

[0054] By including a plurality of layers in the insulating resin film 15, the mechanical strength of the insulating resin film 15, the adhesion between the insulating resin film 15 and the exterior body 11, and the adhesion between the insulating resin film 15 and the conductor 14 can be adjusted after thermally welding the insulating resin film 15 to the exterior body 11.

[0055] The first insulating resin film 151 and the second insulating resin film 152 may have different numbers of layers, materials contained in each layer, compositions, etc., or they may be the same.

Example

[0056] Specific examples will be given below for explanation, but the present invention is not limited to these examples.

[0057] The leads produced in each experimental example and the evaluation methods will be described below.

[0058] Experimental Example 2 and Experimental Example 3 are examples, and Experimental Example 1 and Experimental Example 4 are comparative examples. In any of Experimental Example 1 to Experimental Example 4, 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 and 3A was produced.

[0059] The first insulating resin film 151 and the second insulating resin film 152 each have two layers, a first layer 31 containing maleic anhydride-modified polypropylene and a second layer 32, starting from a position close to the conductor 14.

[0060] The melting point of the base resin and the softening point of the additive component contained in the second layer 32 are as shown in Table 1. Table 1 also shows the content ratio of the additive component in the second layer 32.

[0061] The melting point of the base resin was measured by a differential scanning calorimeter (DSC). The softening point of the additive component was measured by a nano TA (Thermal Analysis System).

[0062] Among the second layer 32, the melting point of the base resin was measured by measuring the endothermic reaction during the melting of the base resin. Specifically, for the second layer 32, the temperature was raised at 10 °C / min for measurement.

[0063] Also, by heating the micro-region in contact with the probe and utilizing the fact that when the sample softens, the probe penetrates into the sample and thermomechanical analysis can be performed, the distribution of the softening point of the additive component in the second layer 32 was measured. Separatory-NMR·GPC analysis was performed on the second layer 32 in advance to analyze the contained components, and by combining with the distribution of the softening point in the second layer 32, the softening point of the contained additive component was determined. Also, the content ratio of the additive component was determined by separatory-NMR·GPC analysis.

[0064] The second layer 32 contains a polypropylene random copolymer as the base resin and an ethylene-propylene rubber as the additive component.

[0065] The base resin of the second layer 32 is crosslinked. (Seal strength test) In this experimental example, the exterior body 11 was heat-sealed to the lead 13. 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 an aluminum foil.

[0066] For the one in which the exterior body 11 was heat-sealed to the lead 13, the rectangular region shown by the dashed line in FIG. 1 was cut with a die cutter to obtain a test piece 16. The width W16 of the test piece 16 was 10 mm.

[0067] Then, as shown in Fig. 4, when the exterior body 11 was folded back, the exposed portion of the conductor 14 was sandwiched by the chuck 41. At this time, the contact plate 42 was applied to the second exterior body 11B arranged so as to cover the lower surface 142 of the conductor 14, and the test piece 16 was supported so as not to tilt.

[0068] Next, after heating the test piece 16 to each test temperature, the first exterior body 11A arranged so as to cover the upper surface 141 of the conductor 14 was pulled by a tensile testing machine as shown by the block arrow B in Fig. 4. Then, the tensile load when the first exterior body 11A was peeled off from the first insulating resin film 151 was defined as the seal strength.

[0069] The test temperatures were 100 °C, 110 °C, 120 °C, and 130 °C. Test pieces 16 were prepared for each test temperature, and the tests were carried out.

[0070] The evaluation results are shown in Fig. 5. (Heating deformation residual rate) For the insulating resin film 15 of the lead in this experimental example, a crushing experiment was carried out using a thermomechanical analyzer. Specifically, while applying pressure to the surface of the second layer 32 of the insulating resin film 15 with a probe, heating and temperature increase were performed, and the heating deformation residual rate was measured. The heating rate was 10 °C / min, and the pressure applied to the second layer 32 was 0.10 MPa.

[0071] The evaluation results are shown in Fig. 6. [From Experimental Example 2 to Experimental Example 4] The grade and blending ratio of each raw material were changed so that the melting point of the base resin, the softening point of the additive component, and the temperature and ratio shown in Table 1 for the content ratio of the additive component in the second layer 32 were obtained.

[0072] Except for the above points, leads were produced under the same conditions as in Experimental Example 1.

[0073] Using the produced leads, a seal strength test was carried out in the same procedure as in Experimental Example 1. The evaluation results are shown in Fig. 5.

[0074] For Experimental Example 3, the heat deformation residual rate was measured in the same procedure as in Experimental Example 1. The evaluation results are shown in FIG. 6.

[0075]

Table 1

[0076] Also, according to FIG. 6, in both Experimental Example 1 and Experimental Example 3, since the resin of the second layer was crosslinked, it was confirmed that the heat deformation residual rate exceeded 80% and it would not be crushed even when heat welding was performed.

Explanation of Reference Signs

[0077] 10 Battery 11 Exterior body 11A First exterior body 11B Second 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 15 Insulating resin film 151 First insulating resin film 152 Second insulating resin film 16 Test piece 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 First Layer 32 Second Layer 33 Third Layer 41 Chuck 42 Platen 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; 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 orthogonal to the X-axis as the Y-axis, the first insulating resin film and the second insulating resin film are arranged to cover the conductor across the conductor along the X-axis, protrude from both ends of the conductor and overlap, and do not cover both ends of the conductor along the Y-axis; the first insulating resin film and the second insulating resin film each include a plurality of layers with different compositions; the first insulating resin film and the second insulating resin film each have a first layer in contact with the conductor and a second layer different from the first layer; the second layer includes a base resin mainly composed of polypropylene and one or more additive components selected from a rubber component and an elastomer component; the melting point of the base resin is 110°C or higher and 130°C or lower, and the softening point of the additive component is 130°C or lower; the second layer contains the additive component at a ratio of 10% by mass or more and 40% by mass or less, a lead with an insulating resin film.

2. The lead with an insulating resin film according to claim 1, wherein the base resin of the second layer is crosslinked.

Images