Lead with insulating resin film

Abstract

The invention provides a lead with an insulating resin film. A lead wire with an insulating resin film has a conductor and an insulating resin film, and the insulating resin film is disposed so as to cover the conductor so as to traverse the conductor along the X-axis, extend from both ends of the conductor, and overlap the conductor when the X-axis is the axis along the two opposing sides and the Y-axis is the axis orthogonal to the X-axis when the conductor is viewed from above. And an insulating resin film disposed so as not to cover both ends of the conductor along the Y-axis, the insulating resin film having a first layer in contact with the conductor and a second layer containing: a matrix resin having polypropylene as a main component; and at least one additive component selected from a rubber component and an elastomer component, the melting point of the matrix resin being 110-130 DEG C inclusive, the softening point of the additive component being 130 DEG C or less, and the second layer containing 10-40 mass% inclusive of the additive component.

Description

Technical Field

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

[0002] Patent Document 1 discloses an electric storage device including at least: an electric storage device element including a positive electrode, a negative electrode, and an electrolyte; an outer casing member for the electric storage device that seals the electric storage device element; and the metal terminals that are electrically connected to the positive electrode and the negative electrode respectively and protrude outside the outer casing member for the electric storage device, and an adhesive film for the metal terminal is interposed between the metal terminal and the outer casing member for the electric storage device.

[0003] Prior Art Documents

[0004] Patent Documents

[0005] Patent Document 1: WO 2021 / 201213

[0006] Inside the outer casing that seals various batteries, sometimes electrolytes and the like generate heat due to reactions, the battery becomes high temperature exceeding the usable temperature, and gas is generated. From the viewpoint of avoiding breakage of the battery and the like, it is required to be configured to discharge the gas generated in the region sealed by the outer casing to the outside of the region sealed by the outer casing. Summary of the Invention

[0007] An object of the present disclosure is to provide a lead wire with an insulating resin film that, when applied to a battery, can discharge the gas generated in the region sealed by the outer casing of the battery to the outside of the region sealed by the outer casing.

[0008] The lead wire with an insulating resin film of the present disclosure has: a plate-shaped conductor, the upper surface and the lower surface of the conductor having a rectangular shape; 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 observing the conductor from above in the vertical direction along the upper surface, and setting the axes 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 configured to cover the conductor in a manner crossing the conductor along the X-axis, extend from both ends of the conductor, and overlap, and are configured not to 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 including: a base resin with polypropylene as the main component; and an additive component selected from one or more of a rubber component and an elastomer component. The melting point of the base resin is 110 °C or higher and 130 °C or lower, the softening point of the additive component is 130 °C or lower, and the second layer contains the additive component in a proportion of 10% by mass or more and 40% by mass or less.

[0009] Advantages of the Invention

[0010] According to the present disclosure, a lead wire with an insulating resin film can be provided, which can discharge the gas generated in the region sealed by the outer casing of the battery to the outside of the region sealed by the outer casing when applied to the battery. Description of the Drawings

[0011] Figure 1 It is an explanatory diagram of a battery of a lead wire with an insulating resin film to which one embodiment of the present disclosure is applied.

[0012] Figure 2 It is a top view of a lead wire with an insulating resin film according to one embodiment of the present disclosure.

[0013] Figure 3A is Figure 1 a cross-sectional view taken along line A - A' of

[0014] Figure 3B is Figure 1 another configuration example of the cross-sectional view taken along line A - A' of

[0015] Figure 4 It is an explanatory diagram of a method for measuring the temperature dependence of the sealing strength.

[0016] Figure 5It is the evaluation result of the temperature dependence of the sealing strength in the experimental example.

[0017] Figure 6 It is the evaluation result of the residual rate of thermal deformation in the experimental example.

[0018] Explanation of reference numerals

[0019] 10: Battery;

[0020] 11: Outer housing;

[0021] 11A: First outer housing;

[0022] 11B: Second outer housing;

[0023] 110: Sealing portion;

[0024] 111: First resin layer;

[0025] 112: Metal layer;

[0026] 113: Second resin layer;

[0027] 12: Electrode laminate;

[0028] 13: Lead wire (lead wire with insulating resin film);

[0029] 14: Conductor;

[0030] 141: Upper surface;

[0031] 142: Lower surface;

[0032] 15: Insulating resin film;

[0033] 151: First insulating resin film;

[0034] 152: Second insulating resin film;

[0035] 16: Test piece;

[0036] 21: Side;

[0037] 22: Side;

[0038] 23: Side;

[0039] 24: Side;

[0040] 25: First end region;

[0041] 26: Second end region;

[0042] L14: Length;

[0043] W14: Length;

[0044] L15: Length;

[0045] W15: Length;

[0046] 31: The first layer;

[0047] 32: The second layer;

[0048] 33: The third layer;

[0049] 41: Chuck;

[0050] 42: Contact plate;

[0051] X: X-axis;

[0052] Y: Y-axis;

[0053] Z: Z-axis. Detailed implementation manners

[0054] Hereinafter, the implementation manners for implementation will be described.

[0055] [Description of the implementation manners of the present disclosure]

[0056] First, the implementation schemes of the present disclosure will be listed for description. 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.

[0057] (1) The lead wire with an insulating resin film according to one scheme of the present disclosure has: a plate-shaped conductor, the upper and lower surfaces of which have a rectangular shape; 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 observing the conductor from above in the vertical direction along the upper surface, and setting 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 configured to cover the conductor in a manner of crossing the conductor along the X-axis and extend and overlap from both ends of the conductor, and are configured not to 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 matrix resin mainly composed of polypropylene; and an additive component selected from one or more of a rubber component and an elastomer component. The melting point of the matrix resin is 110°C or higher and 130°C or lower, the softening point of the additive component is 130°C or lower, and the second layer contains the additive component in a proportion of 10% by mass or higher and 40% by mass or lower.

[0058] Note that in this specification, the lead with an insulating resin film may sometimes be simply referred to as "lead".

[0059] By setting the melting point of the matrix resin contained in the second layer to 130°C or lower, when the battery exceeds the usable temperature and becomes high temperature, the adhesion between the second layer and other members in contact with the second layer can be reduced. Therefore, even when the battery exceeds the usable temperature and becomes high temperature, if gas is generated in the area sealed by the outer casing, the gas can be discharged outside the area sealed by the outer casing.

[0060] Note that in this specification, other members in contact with the second layer refer to layers other than the second layer included in the insulating resin film in contact with the second layer. When the second layer is in contact with the outer casing, it refers to the outer casing.

[0061] In addition, by setting the melting point of the matrix resin to 110°C or higher, it is possible to prevent the adhesion between the second layer and other members in contact with the second layer from decreasing in the temperature range where basically no gas is generated in the area sealed by the outer casing, and it is possible to seal the electrode laminate and the electrolyte.

[0062] By including an additive component in the second layer, when a force is applied to the insulating resin film in a manner that peels the lead from the outer casing, the stress applied to the insulating resin film can be alleviated, and the adhesion between the second layer and other members in contact with the second layer can be improved. In addition, by setting the softening point of the additive component to 130°C or lower, it can be configured such that when the battery exceeds the usable temperature and becomes high temperature, the gas generated in the area sealed by the outer casing can be discharged outside the area sealed by the outer casing.

[0063] 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 in a manner that peels the lead from the outer casing, the stress applied to the insulating resin film can be alleviated, and the adhesion between the second layer and other members in contact with the second layer can be improved. In addition, 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.

[0064] (2) In the above (1), it may also be that the matrix resin of the second layer is crosslinked.

[0065] When manufacturing the battery, by arranging the outer casing on the upper and lower surfaces of the lead and heating the area including the overlapping part of the insulating resin film and the outer casing of the lead while applying pressure, the lead can be heat-sealed to the outer casing. By crosslinking the matrix resin contained in the second layer, it is possible to prevent the insulating resin film from being crushed when the lead is heat-sealed to the outer casing. Therefore, the shape of the insulating resin film can be stabilized, and the adhesion of the lead to the outer casing can also be improved.

[0066] [Details of Embodiments of the Present Disclosure]

[0067] Hereinafter, a specific example of a lead wire with an insulating resin film according to an embodiment of the present disclosure (hereinafter referred to as "this embodiment") will be described with reference to the accompanying drawings. It should be noted that the present invention is not limited to these examples, but is shown in the claims and is intended to include all modifications within the meaning and scope equivalent to the claims.

[0068] In this specification, sometimes the names of components are described by adding first, second, etc., such as the first insulating resin film and the second insulating resin film. The first, second, etc. are only described for identifying each component and preventing confusion during the description, and do not indicate the configuration, priority order, etc. Therefore, in the case where there is no particular concern about confusion and in the case of unified representation, it can be simply referred to as the insulating resin film.

[0069] [Lead Wire with Insulating Resin Film]

[0070] Figure 1 FIG. shows an explanatory diagram of a configuration example in the case where the lead wire with an insulating resin film of this embodiment is applied to a battery. Figure 2 It is an explanatory diagram when observing the lead wire with an insulating resin film of this embodiment vertically above the upper surface of the conductor. Figure 3A FIG. shows Figure 1 a cross-sectional view taken along line A - A' of Figure 3B FIG. shows Figure 1 another configuration example corresponding to the cross-sectional view taken along line A - A' of Figure 3B This is a modified example of the lead wire with an insulating resin film of this embodiment, and thus it is assumed that: mainly use Figure 1 , Figure 2 , Figure 3A for the description, and use Figure 3B as needed.

[0071] Figure 1 , Figure 2 , Figure 3A , Figure 3B In the Z-axis in, is the axis along the thickness of the conductor and the insulating resin film of the lead wire of this embodiment.

[0072] The lead wire 13 of this embodiment can be applied to a battery. Therefore, after describing the battery to which the lead wire 13 of this embodiment can be applied, the details of the lead wire 13 of this embodiment will be described.

[0073] (1) Regarding the Battery

[0074] A configuration example of the battery to which the lead wire 13 of this embodiment is applied is shown in Figure 1 As shown inFigure 1 As shown, the battery 10 may have: an outer casing 11; an electrode laminate 12 in which a positive electrode, a separator, and a negative electrode are laminated and which is impregnated with an electrolytic solution; and a lead wire 13 according to an aspect of the present disclosure, which is connected to the electrode laminate 12.

[0075] (Outer casing)

[0076] The outer casing 11 is a container that houses and seals the electrode laminate 12 and the electrolytic solution. The outer casing 11 may have at least one resin layer on the surface opposite to the electrode laminate 12 so that heat fusion can be performed.

[0077] As Figure 1 shown by the single-dot chain line in the figure, a sealing portion 110 is formed at the periphery of the outer casing 11, and the electrode laminate 12 and the electrolytic solution are sealed by the sealing portion 110. The region surrounded by the sealing portion 110 is the region sealed by the outer casing 11.

[0078] (2) Regarding the lead wire

[0079] The members of the lead wire 13 in the present embodiment, namely the conductor 14 and the insulating resin film 15, will be described.

[0080] (2-1) Conductor

[0081] The conductor 14 is a member for connecting the electrode laminate 12 disposed inside the outer casing 11 to a device group disposed outside the outer casing 11. The conductor 14 may have a plate-like shape, and its upper surface 141 and lower surface 142 (see Figure 3A ) have a rectangular shape. As Figure 2 shown, the upper surface 141 of the conductor 14 has sides 21 and 22 as two opposite sides and sides 23 and 24 that intersect sides 21 and 22. However, the rectangular shape does not refer to a strictly geometric shape, and the conductor 14 may also have a shape with rounded corners.

[0082] In the following description, when observing the conductor 14 from above in the vertical direction along the upper surface 141, the axis along the two selected opposite sides, namely sides 21 and 22, is defined as the X-axis. In addition, the axis orthogonal to the X-axis is defined as the Y-axis.

[0083] The material of the conductor 14 is not particularly limited, and for example, various materials that have been used for lead wires can be used. As the material of the conductor 14, for example, metal materials such as aluminum, titanium, nickel, copper, aluminum alloy, titanium alloy, nickel alloy, and copper alloy, and materials obtained by plating these metal materials with nickel, gold, etc. can be cited.

[0084] (2-2) Insulating resin film

[0085] As Figure 3AAs shown, 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 Figure 2 , Figure 3A shown, 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 such that they do not cover the two end portions of the conductor 14 along the Y-axis, that is, the two end portions including the side 21 and the side 22, but expose them. 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 in a manner crossing the conductor 14 along the X-axis at a portion other than the two end portions of the conductor 14 along the Y-axis, that is, the middle portion.

[0086] The upper surface 141 and the lower surface 142 of the conductor 14 refer to the surfaces facing the outer casing 11 of the battery 10 when manufacturing the battery 10.

[0087] As Figure 2 shown, the two end portions of the conductor 14 along the Y-axis refer to a first end portion region 25 including the side 21 and a second end portion region 26 including the side 22. The middle portion is the portion located between the first end portion region 25 and the second end portion region 26.

[0088] When applying the lead 13 to the battery, for example, the first end portion region 25 is the portion exposed outside the outer casing 11, and its size can be selected in a manner that can be connected to an external device group. In addition, when applying the lead 13 to the battery, for example, the second end portion region 26 is the portion located inside the outer casing 11 and connected to the electrode laminate 12, and its size can be selected in a manner that can be connected to the electrode laminate 12. The sizes such as the areas of the first end portion region 25 and the second end portion region 26 can be the same or different.

[0089] Therefore, the length L14 of the conductor 14 along the Y-axis is longer than the length L15 of the insulating resin film 15. In addition, the length W15 of the insulating resin film 15 is longer than the length W14 of the conductor 14 along the X-axis.

[0090] As Figure 2 shown, the first insulating resin film 151 and the second insulating resin film 152 are arranged to extend from the two end portions 14C of the conductor along the X-axis and overlap each other. In the portion extending from the conductor 14, the first insulating resin film 151 is in direct contact with and adheres to the second insulating resin film 152.

[0091] The lead 13 of the present embodiment is sealed with the sealing portion 110 (refer to Figure 1 ) through the insulating resin film 15 portion.

[0092] The inventors of the present invention have studied the following lead wire 13: when the battery exceeds the usable temperature and becomes high temperature, and thus gas or the like is generated inside the battery 10 where the electrode laminate 12 and the like are sealed by the outer casing 11, the gas in the area sealed by the outer casing 11 can be discharged to the outside. And it has been found that by making the second layer 32 (refer to Figure 3A ) in the insulating resin film 15 of the lead wire 13 have a specified structure, when gas is generated in the area sealed by the outer casing 11, the adhesion force between the second layer 32 and other members in contact with the second layer 32 will decrease. Therefore, it has been found that when gas is generated in the area sealed by the outer casing 11, the gas can be discharged outside the area sealed by the outer casing 11, and thus the present invention has been completed.

[0093] (2-2-1) Second layer

[0094] The insulating resin film 15 of the lead wire 13 in this embodiment, that is, the first insulating resin film 151 and the second insulating resin film 152, may each include a plurality of layers with different compositions. And 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 may contain: a matrix resin, with polypropylene as the main component; and an additive component, which is one or more selected from rubber components and elastomer components. Having polypropylene as the main component means that among the components contained in the matrix resin, polypropylene is contained in the largest mass ratio.

[0095] (Matrix resin)

[0096] The melting point of the matrix 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 making the melting point of the matrix resin contained in the second layer 32 130 °C or lower, when the battery exceeds the usable temperature and becomes high temperature, the adhesion force between the second layer 32 and other members in contact with the second layer 32 can be decreased. Therefore, even when the battery exceeds the usable temperature and becomes high temperature, and gas is generated in the area sealed by the outer casing 11, the gas can be discharged outside the area sealed by the outer casing 11.

[0097] In addition, by making the melting point of the matrix resin 110 °C or higher, it is possible to prevent the adhesion force between the second layer and other members in contact with the second layer from decreasing in the temperature range where basically no gas is generated in the area sealed by the outer casing, and it is possible to seal the electrode laminate and the electrolyte.

[0098] The matrix resin contained in the second layer 32 may consist only of polypropylene, or may contain, in addition to polypropylene, a resin that enables the melting point of the matrix resin to be within the above temperature range. As the polypropylene, one or more selected from among homopolymers, block copolymers, and random copolymers of polypropylene can be used.

[0099] A polypropylene homopolymer is a polymer of only propylene.

[0100] A polypropylene block copolymer is a copolymer having a polymer block composed of propylene and a polymer block composed of an α-olefin other than propylene.

[0101] A polypropylene random copolymer is a random copolymer of propylene and an α-olefin other than propylene. Examples of the α-olefin other than propylene include ethylene and the like.

[0102] Examples of the resin other than polypropylene that can be contained in the matrix resin include one or more selected from among polystyrene, polyvinyl alcohol, polyvinyl acetate, acrylic resins, ABS resins (acrylonitrile-butadiene-styrene copolymer resins), polyester resins, fluorine resins, and the like.

[0103] The matrix resin contained in the second layer 32 may also be crosslinked.

[0104] When manufacturing the battery 10, by disposing the outer casing 11 on the upper and lower surfaces of the lead 13 of the present embodiment and heating the region of the lead 13 including the portion where the insulating resin film 15 overlaps with the outer casing 11 while applying pressure, the lead 13 can be heat-sealed to the outer casing 11. By crosslinking the matrix resin contained in the second layer 32, when the lead 13 is heat-sealed to the outer casing 11, the insulating resin film 15 can be prevented from being crushed. Therefore, the shape of the insulating resin film 15 can be stabilized, and the adhesion of the lead 13 to the outer casing 11 can also be improved.

[0105] (Additive component)

[0106] By making the second layer 32 contain an additive component, when a force is applied to the insulating resin film 15 in a manner that peels the lead 13 from the outer casing 11, the stress applied to the insulating resin film 15 can be alleviated, and the adhesion between the second layer 32 and other members in contact with the second layer 32 can be improved.

[0107] The additive components contained in the second layer 32 are not particularly limited, and the softening point of the additive components can be set to 130°C or lower. By setting the softening point of the additive components to 130°C or lower, it is possible to configure such that when the battery exceeds the usable temperature and becomes high temperature, the gas generated in the region sealed by the outer casing 11 can be discharged outside the region sealed by the outer casing 11. The lower limit value of the softening point of the additive components is not particularly limited, and can be, for example, 35°C or higher, or 40°C or higher.

[0108] The second layer 32 may also contain additive components in a proportion of 10% by mass or more and 40% by mass or less. By setting the content ratio of the additive components in the second layer 32 to 10% by mass or more, when a force is applied to the insulating resin film 15 in a manner of peeling the lead wire 13 from the outer casing 11, the stress applied to the insulating resin film 15 can be alleviated. And the adhesion force between the second layer 32 and other members in contact with the second layer 32 can be improved. In addition, by setting the content ratio of the additive components 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.

[0109] The additive components contained in the second layer 32 are not particularly limited, and the types and mixing ratios of the additive components contained can be adjusted such that the softening point of the additive components becomes 130°C or lower. As the additive components contained in the second layer 32, for example, 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, etc. can be cited.

[0110] The additive components contained in the second layer 32 may be composed of only one additive component, or may be a mixture of two or more additive components.

[0111] (2-2-2) The first layer, the third layer

[0112] The insulating resin film 15 may also include layers other than the second layer 32.

[0113] As the first insulating resin film 151 and the second insulating resin film 152 of the insulating resin film 15, each may also be as Figure 3A , Figure 3B shown to include two or more layers.

[0114] As Figure 3A shown, 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.

[0115] By making the first insulating resin film 151 and the second insulating resin film 152 composed of only two layers, the number of processes in manufacturing the insulating resin film 15 and the lead wire 13 can be suppressed, and the productivity can be improved.

[0116] As Figure 3B shown, 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 Figure 3B , they are arranged in the order of the first layer 31, the third layer 33, and the second layer 32 starting from a position close to the conductor 14, and the second layer 32 is in contact with the outer housing 11, but this is not limited to this solution. For example, they may also be arranged in the order of the first layer 31, the second layer 32, and the third layer 33 starting from a position close to the conductor 14, and the third layer 33, which is a layer other than the second layer 32, is in contact with the outer housing 11.

[0117] Figure 3A , Figure 3B merely as examples, the first insulating resin film 151 and the second insulating resin film 152 may each have any number of layers of two or more.

[0118] In the case where the insulating resin film 15 has multiple layers, the functions can also be separated by each layer. In the case where the insulating resin film 15 includes three layers, for example, the functions can also be separated as a layer adhered to the conductor 14, a layer adhered to the outer housing 11, and a layer that is not easily crushed when the lead 13 is fused to the outer housing 11 to maintain mechanical strength.

[0119] In the case where the insulating resin film 15 includes multiple layers, the layers other than the second layer 32 may also contain resin. The layers other than the second layer 32 of the insulating resin film 15 may contain, for example, a thermoplastic resin as the resin. As the thermoplastic resin, for example, one or more selected from polyolefin resins, polyester resins, polystyrene resins, polyvinyl chloride resins, etc. can be used. As the polyolefin resin, acid-modified polyolefin resins such as polyethylene, polypropylene, acid-modified polyethylene, and acid-modified polypropylene can be cited. As the polyester resin, for example, polyethylene terephthalate resin can be cited. As the acid-modified polyolefin, maleic anhydride-modified polyolefin can be cited.

[0120] The materials of the respective layers of the insulating resin film 15 can be selected according to the target functions, etc. For example, in terms of adhesion, the layer adhered to the conductor 14 is preferably acid-modified polypropylene.

[0121] By making the insulating resin film 15 include multiple layers, the mechanical strength of the insulating resin film 15 after heat-fusing the insulating resin film 15 to the outer housing 11, the adhesion between the insulating resin film 15 and the outer housing 11, and the adhesion between the insulating resin film 15 and the conductor 14 can be adjusted.

[0122] In the first insulating resin film 151 and the second insulating resin film 152, the number of layers contained, the materials contained in each layer, the composition, etc. may be different or the same.

[0123] [Embodiment]

[0124] Hereinafter, specific embodiments will be listed for illustration, but the present invention is not limited to these embodiments.

[0125] Hereinafter, the leads produced in each experimental example and the evaluation method will be described.

[0126] Experimental Example 2 and Experimental Example 3 are embodiments, and Experimental Example 1 and Experimental Example 4 are comparative examples. In Experimental Examples 1 to 4, the first insulating resin film 151 and the second insulating resin film 152 are configured in the same manner.

[0127] [Experimental Example 1]

[0128] The lead 13 shown in Figure 2 and Figure 3A was fabricated.

[0129] The first insulating resin film 151 and the second insulating resin film 152 each have two layers, namely the first layer 31 and the second layer 32, starting from a position close to the conductor 14. Among them, the first layer 31 contains maleic anhydride-modified polypropylene.

[0130] The melting point of the matrix resin and the softening point of the additive component contained in the second layer 32 are shown in Table 1. In addition, the content ratio of the additive component in the second layer 32 is also shown in Table 1.

[0131] The melting point of the matrix resin is measured by a differential scanning calorimeter (DSC: Differential Scanning Calorimeter). The softening point of the additive component is measured by a nano TA (Thermal Analysis System).

[0132] The melting point of the matrix resin is measured by measuring the endothermic reaction during the melting of the matrix resin in the second layer 32. Specifically, for the second layer 32, the temperature is raised at a rate of 10 °C / min for measurement.

[0133] In addition, the minute area in contact with the probe is heated, and the distribution of the softening points of the additive components in the second layer 32 is measured by utilizing the phenomenon that the probe can penetrate into the interior of the specimen when the specimen softens. The second layer 32 is pre-analyzed by classification-NMR (Nuclear Magnetic Resonance) / GPC (Gel Permeation Chromatography) to pre-analyze the contained components, and combined with the distribution of the softening points in the second layer 32, thereby obtaining the softening points of the contained additive components. In addition, the content ratio of the additive components is obtained by classification-NMR / GPC analysis.

[0134] The second layer 32 contains a polypropylene random copolymer as the matrix resin and an ethylene-propylene rubber as the additive component.

[0135] The matrix resin of the second layer 32 is crosslinked.

[0136] (Sealing strength test)

[0137] The outer casing 11 is heat-sealed to the lead 13 of this experimental example. As the outer casing 11, a laminated film 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 is used.

[0138] For the member obtained by heat-sealing the outer casing 11 to the lead 13, a rectangular area indicated by the single dotted line as shown in Figure 1 is cut out by a die cutter to obtain a test piece 16. The width W16 of the test piece 16 is 10 mm.

[0139] Then, as shown in Figure 4 , when the outer casing 11 is folded back, the exposed conductor 14 portion is clamped by the chuck 41. At this time, the abutment plate 42 is abutted against the second outer casing 11B arranged to cover the lower surface 142 of the conductor 14, and the test piece 16 is supported in a non-tilting manner.

[0140] Next, after heating the test piece 16 to each test temperature, as shown by the thick arrow B in Figure 4 , the first outer casing 11A arranged to cover the upper surface 141 of the conductor 14 is pulled by a tensile testing machine. And the tensile load when the first outer casing 11A is peeled from the first insulating resin film 151 is defined as the sealing strength.

[0141] The test temperatures are set to 100 °C, 110 °C, 120 °C, and 130 °C. Test pieces 16 are prepared for each test temperature and the tests are carried out.

[0142] The evaluation results are shown in Figure 5 .

[0143] (Thermal deformation residue rate)

[0144] For the insulating resin film 15 of the lead wire in this experimental example, a crushing experiment was carried out using a thermomechanical analysis device. 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 carried out, and the thermal deformation residue rate was measured. The heating rate was set to 10 °C / min, and the pressure applied to the second layer 32 was set to 0.10 MPa.

[0145] The evaluation results are shown in Figure 6 。

[0146] [Experimental examples 2 to 4]

[0147] The grade and mixing ratio of each raw material were changed so that the melting point of the matrix resin contained in the second layer 32, the softening point of the additive component, and the content ratio of the additive component in the second layer 32 became the temperatures and ratios shown in Table 1.

[0148] Except for the above points, leads were made under the same conditions as in Experimental Example 1.

[0149] Using the made leads, a sealing strength test was carried out through the same process as in Experimental Example 1. The evaluation results are shown in Figure 5 。

[0150] In addition, for Experimental Example 3, the thermal deformation residue rate was measured through the same process as in Experimental Example 1. The evaluation results are shown in Figure 6 。

[0151] [Table 1]

[0152]

[0153] According to Figure 5 It can be confirmed that when using the leads of Experimental Example 2 and Experimental Example 3, compared with the case of using the leads of Experimental Example 1 and Experimental Example 4, the sealing strength, that is, the bonding strength of the insulating resin film to the outer casing 11, drops sharply from 110 °C to 130 °C. Therefore, it can be confirmed that the leads of Experimental Example 2 and Experimental Example 3 are leads that can discharge the gas generated in the area sealed by the outer casing 11 to the area outside the area sealed by the outer casing.

[0154] In addition, according to Figure 6 It can be confirmed that since the resin in the second layer is crosslinked in Experimental Example 1 and Experimental Example 3, the thermal deformation residue rate exceeds 80%, and it will not be crushed even in the case of hot melt bonding.

Claims

1. A lead wire with an insulating resin film, wherein, the lead wire with an insulating resin film has: a plate-shaped conductor, the upper surface and the lower surface of the conductor having a rectangular shape; 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 observing the conductor from above in the vertical direction along the upper surface, setting 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 configured to cover the conductor in a manner of crossing the conductor along the X-axis, extend from both ends of the conductor and overlap, and are configured not to 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 contains: a matrix resin mainly composed of polypropylene; and an additive component selected from one or more of a rubber component and an elastomer component, the melting point of the matrix 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.

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

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