Lead member

Abstract

A lead member comprising a conductor foil and a pair of insulating films, wherein the conductor foil has a first main surface extending in a first direction and a second main surface opposite to the first main surface, the second main surface extending in a second direction orthogonal to the first direction, and the pair of insulating films are attached to a part of the first main surface and the second main surface so as to straddle both side surfaces of the conductor foil along the first direction, and the conductor foil has a rectangular shape with one corner rounded in a plan view along a third direction orthogonal to the first direction and the second direction, and the side surface of the rounded corner has a sheared surface and a fractured surface, the sheared surface being adjacent to the first main surface and the fractured surface being adjacent to the second main surface.

Description

Technical Field

[0001] The present disclosure relates to a lead member. This application claims priority based on Japanese Application No. 2024-013187 filed on January 31, 2024, and incorporates by reference all the descriptions set forth in the above-mentioned Japanese application.

Background Art

[0002] Patent Document 1 discloses a lead member that enables easy identification of the front and back of individual lead members.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

[0004] The lead member according to an embodiment of the present disclosure includes a conductor foil and a pair of insulating films. The conductor foil has a first main surface extending in a first direction and a second main surface opposite to the first main surface. The pair of insulating films are attached to a part of the first main surface and the second main surface so as to straddle both side surfaces of the conductor foil along the first direction. The conductor foil has a rectangular shape with one corner rounded in a plan view along a third direction orthogonal to the first direction and the second direction. The side surface of the rounded corner has a sheared surface and a fractured surface. The sheared surface is adjacent to the first main surface, and the fractured surface is adjacent to the second main surface.

Brief Description of the Drawings

[0005]

Figure 1

Figure 2

Figure 3

Figure 4

Embodiments for Carrying Out the Invention

[0006] [Problems to be Solved by the Present Disclosure] In the manufacturing process of the lead member, protrusions called burrs may occur when the conductor foil is cut. For example, if the surface with burrs is welded to the electrode foil, the electrode foil may break.

[0007] An object of the present disclosure is to provide a lead member with small burrs.

[0008] [Effects of the Present Disclosure] According to the present disclosure, a lead member with small burrs can be provided.

[0009] [Description of Embodiments of the Present Disclosure] First, embodiments of the present disclosure will be listed and described. A lead member according to an embodiment of the present disclosure includes (1) a conductor foil and a pair of insulating films. The conductor foil has a first main surface extending in a first direction and a second main surface opposite to the first main surface. The pair of insulating films are attached to a part of the first main surface and the second main surface so as to straddle both side surfaces of the conductor foil along the first direction. The conductor foil has a rectangular shape with one corner being a rounded corner portion in a plan view seen along a third direction orthogonal to the first direction and the second direction. The side surface of the rounded corner portion has a sheared surface and a fractured surface. The sheared surface is adjacent to the first main surface, and the fractured surface is adjacent to the second main surface.

[0010] Since the above lead member has one rounded corner portion, the shape of the lead member becomes asymmetric, so it is easy to distinguish the front and back of the lead member. Since both the sheared surface and the fractured surface are present on the cut surface, the burrs can be reduced.

[0011] (2) In the lead member of (1) above, the area ratio of the fracture surface to the total area of the shearing surface and the fracture surface may be 0.5 or less.

[0012] When the ratio of the shearing surface to the fracture surface is within the above range, burrs are small and chipping is less likely to occur when rounding the corners.

[0013] (3) In the lead member of (1) or (2) above, the area ratio of the fracture surface to the total area of the shearing surface and the fracture surface may be 0.2 or more.

[0014] When the ratio of the shearing surface to the fracture surface is within the above range, it is easy to form the shearing surface and the fracture surface with a desired area ratio.

[0015] (4) In any one of the lead members of (1) to (3) above, the area of the shearing surface may be larger than the area of the fracture surface.

[0016] According to the above configuration, furthermore, burrs are small and chipping is less likely to occur when rounding the corners.

[0017] (5) In any one of the lead members of (1) to (4) above, the length of the rounded corner portion along the second direction may be longer than the length of the rounded corner portion along the first direction.

[0018] According to the above configuration, the influence due to the variation in width can be reduced.

[0019] [Details of Embodiments of the Present Disclosure] Specific examples of the lead member of the present disclosure will be described below with reference to the drawings. The present invention is not limited to these examples, and is intended to be indicated by the claims and to include all modifications within the meaning and scope equivalent to the claims.

[0020] FIG. 1 is a perspective view of a lead member 1 according to an embodiment of the present disclosure. In the following description, the X direction in FIG. 1 corresponds to the first direction (length direction), the Y direction corresponds to the second direction (width direction), and the Z direction corresponds to the third direction (thickness direction). The first direction, the second direction, and the third direction are each perpendicular to the other two directions.

[0021] As shown in FIG. 1, the lead member 1 according to this embodiment has a conductor foil 2 and an insulating film 3. The conductor foil 2 has a first main surface 2a extending in the first direction and the second direction, and a second main surface 2b facing in a direction opposite to the first main surface 2a. The conductor foil 2 has two side surfaces 2c, 2d and two side surfaces 2e, 2f. The side surfaces 2c and 2d connect the first main surface 2a and the second main surface 2b at their respective ends along the first direction. The side surfaces 2e and 2f connect the first main surface 2a and the second main surface 2b at their respective ends along the second direction. As will be described later, in this embodiment, the corner between the side surface 2c and the side surface 2e of the conductor foil 2 is rounded to form a rounded corner portion 21.

[0022] The conductor foil 2 is a conductor for extracting electricity from inside the battery. The material of the conductor foil 2 is not particularly limited as long as it can be used as a conductor of a lead member for a non-aqueous electrolyte battery. Examples of the material of the conductor foil 2 include metal materials such as aluminum, titanium, nickel, copper, aluminum alloy, titanium alloy, nickel alloy, copper alloy, and materials obtained by plating any of these metal materials with nickel or gold.

[0023] The dimensions of the conductor foil 2 are not particularly limited. For example, the length in the first direction may be 10 mm or more and 120 mm or less, the length in the second direction may be 3 mm or more and 120 mm or less, and the thickness may be 0.05 mm or more and 3.0 mm or less.

[0024] The insulating film 3 is attached to both main surfaces of the conductor foil 2 and is used to prevent a short circuit between the conductor foil 2 and the encapsulation container 11 (see FIG. 2). More specifically, as shown in FIG. 1, a pair of insulating films 3, that is, an insulating film covering a part of the first main surface 2a and an insulating film covering a part of the second main surface 2b, are adhered to each other at the end of the lead member 1 in the second direction. The insulating film 3 covers a part of each of the first main surface 2a, the second main surface 2b, the side surface 2c, and the side surface 2d, except for the side surfaces 2e and 2f. The pair of insulating films are attached to a part of the first main surface 2a and the second main surface 2b of the conductor foil 2 so as to straddle both side surfaces (side surface 2c and side surface 2d) of the conductor foil 2 along the first direction.

[0025] FIG. 2 is a perspective view showing a non-aqueous electrolyte battery 10 including a lead member 1. The non-aqueous electrolyte battery 10 includes a laminated electrode group (not shown) in which a positive electrode plate, a separator, and a negative electrode plate are laminated in this order, and an electrolytic solution is housed in an encapsulation container 11, and the lead member 1 connected to the positive electrode plate and the negative electrode plate is sealed at a seal portion 12. In the non-aqueous electrolyte battery 10 shown in FIG. 2, the lead member 1 connected to the positive electrode plate and the lead member 1 connected to the negative electrode plate are made of different materials that form the conductor foil 2. The non-aqueous electrolyte battery 10 can be electrically connected between the inside and the outside of the battery through the conductor foil 2 of the lead member 1 while being sealed at the seal portion 12.

[0026] The encapsulation container 11 may be one commonly used as a packaging material for a non-aqueous electrolyte battery, and is formed, for example, of a sheet body in which resin layers are disposed on both surfaces of an aluminum metal foil.

[0027] The lead member 1 of the present disclosure will be described in more detail. FIG. 3 is a plan view of the lead member 1 seen along the third direction. As shown in FIG. 3, the conductor foil 2 has a rectangular shape with one corner rounded as a rounded corner portion 21 in a plan view seen along the third direction. In the present embodiment, the corner between the side surface 2c and the side surface 2e is rounded to form a rounded corner portion 21, and the first main surface 2a and the second main surface 2b have a shape in which one corner of a rectangle is rounded.

[0028] The rounded corner portion 21 has a shape with an edge that is convex outward in a plan view from the third direction. The rounded corner portion 21 can be formed, for example, by cutting off one corner of a conductor foil whose main surface is rectangular by shearing. The length L1 along the first direction and the length L2 along the second direction of the rounded corner portion 21 may each be, for example, 0.1 mm or more and 5.0 mm or less, or may be 0.5 mm or more and 3.0 mm or less.

[0029] FIG. 4 is a view showing a side surface of the rounded corner portion 21, and is a view when the lead member is viewed along the direction of arrow IV in FIG. 1. The direction of arrow IV intersects the second direction at an angle of, for example, 45°. In the present embodiment, a case where the rounded corner portion 21 is formed by bringing a cutting blade into contact with the first main surface 2a of the conductor foil and punching it out in the third direction is shown. As shown in FIG. 4, in the present embodiment, on the side surface of the rounded corner portion 21, the portion adjacent to the first main surface 2a is the sheared surface 21a, and the portion adjacent to the second main surface 2b is the fractured surface 21b. The sheared surface 21a and the fractured surface 21b are formed on the cut surface when the corner of the rectangular conductor foil is cut to provide the rounded corner portion 21. For example, by adjusting the distance between the upper and lower blades at the time of cutting, both the sheared surface 21a and the fractured surface 21b can be formed on the cut surface. When the conductor foil 2 is cut, the end of the first main surface 2a may be pulled at the upper part of the sheared surface 21a shown in FIG. 4 to form a sag. There may be a burr protruding from the second main surface 2b in the third direction at the lower part of the fractured surface 21b shown in FIG. 4. In FIG. 4, the illustration of the sag and the burr is omitted. The expressions "the first main surface 2a and the sheared surface 21a are adjacent" and "the second main surface 2b and the fractured surface 21b are adjacent" in the above description define the positional relationship between the sheared surface 21a and the fractured surface 21b, and do not exclude the case where there is a sag or a burr at the end of the conductor foil 2 in the third direction.

[0030] As described above, when cutting the conductor foil, burrs may occur on the cut portion. For example, when providing a notch in the conductor foil to make it easier to distinguish between the front and back of the lead member, burrs may also occur when cutting the conductor foil to provide the notch. When welding the electrode foil connected to the lead member and the conductor foil, if the surface of the conductor foil with burrs is joined with the electrode foil, the electrode foil may break. Therefore, it is desirable that the lead member be configured so that the surface with burrs and the surface without burrs can be easily distinguished. The occurrence of warping in the direction of burr protrusion is also likely to lead to problems such as breakage of the electrode foil, so it is desirable to reduce the warping of the conductor foil. In order to avoid problems, it is desirable to make the burrs themselves smaller.

[0031] According to the lead member 1 of the present embodiment, since the shape of the lead member 1 becomes asymmetric by having one rounded corner portion, it is easy to distinguish between the front and back of the lead member 1. Since the corners are cut, the warping of the conductor foil 2 can be reduced. Since both the sheared surface 21a and the fractured surface 21b exist on the side surface of the rounded corner portion 21, the burrs can be made smaller compared to, for example, the case where only the sheared surface exists.

[0032] The area ratio AR (A2 / A1) of the area A2 of the fractured surface 21b to the total area A1 of the sheared surface 21a and the fractured surface 21b in the present embodiment will be described. The lower limit of the area ratio AR may be 0.2 or 0.3. The upper limit of the area ratio AR may be 0.5. The area ratio AR may be 0.2 or more and 0.5 or less, or may be 0.3 or more and 0.5 or less. The area of the sheared surface 21a may be larger than the area of the fractured surface 21b. When the area ratio AR is within an appropriate range, the burrs are likely to be small, and chipping or the like is less likely to occur when forming the rounded corner portion 21. The area ratio AR can be controlled, for example, by adjusting the gap between the upper blade and the lower blade.

[0033] In the present embodiment, in a plan view seen along the third direction, the length L2 of the rounded corner portion 21 along the second direction may be longer than the length L1 of the rounded corner portion 21 along the first direction. That is, in FIG. 3, L2 > L1 may be satisfied. When the length L2 is longer than the length L1, the influence due to the variation in width can be reduced.

Example

[0034] Hereinafter, the lead member of the present disclosure will be further described with specific examples, but the lead member of the present disclosure is not limited to these examples.

[0035] [Example 1] One corner of an aluminum conductor foil having a rectangular shape of 45 mm square was cut to form a rounded corner portion with a width of 1.5 mm and a length of 1.5 mm. Only a sheared surface was formed on the side surface of the rounded corner portion. Burrs occurred on one main surface, and the height of the burrs was 0.02 mm.

[0036] [Example 2] One corner of an aluminum conductor foil having a rectangular shape of 45 mm square was cut to form a rounded corner portion with a width of 1.5 mm and a length of 1.5 mm. Both a sheared surface and a fractured surface were formed on the side surface of the rounded corner portion. The ratio of the total area of the sheared surface and the fractured surface to the area of the fractured surface was 0.3. Burrs occurred on the main surface adjacent to the fractured surface, and the height of the burrs was 0.01 mm.

[0037] [Example 3] One corner of an aluminum conductor foil having a rectangular shape of 45 mm square was cut to form a rounded corner portion with a width of 1.5 mm and a length of 1.5 mm. Both a sheared surface and a fractured surface were formed on the side surface of the rounded corner portion. The ratio of the total area of the sheared surface and the fractured surface to the area of the fractured surface was 0.2. Burrs occurred on the main surface adjacent to the fractured surface, and the height of the burrs was 0.01 mm.

[0038] From the comparison with Example 1, Example 2, and Example 3, it was found that when both a sheared surface and a fractured surface are formed on the side surface of the rounded corner portion, the burrs can be made smaller than when only a sheared surface is formed.

[0039] As described above, the lead member of the present disclosure has been described in detail with reference to specific embodiments, but the present disclosure is not limited to these embodiments.

[0040] The corner where the rounded corner portion is formed may be any of the four corners of the conductor foil. Among the four corners of the conductor foil, a rounded corner portion may be formed at the corner that is housed inside the encapsulation container when applied to a non-aqueous electrolyte battery.

Explanation of Signs

[0041] 1 Lead member 2 Conductor foil 2a First main surface 2b Second main surface 2c, 2d, 2e, 2f Side surfaces 21 Rounded corner portion 21a Sheared surface 21b Broken surface 3 Insulating film 10 Non-aqueous electrolyte battery 11 Encapsulation container 12 Seal portion

Claims

1. A lead member comprising a conductor foil and a pair of insulating films, wherein the conductor foil has a first main surface extending in a first direction and a second main surface opposite to the first main surface and extending in a second direction orthogonal to the first direction, the pair of insulating films being attached to a part of the first main surface and the second main surface so as to straddle both side surfaces of the conductor foil along the first direction, the conductor foil having a rectangular shape with one corner rounded in a plan view along a third direction orthogonal to the first direction and the second direction, a side surface of the rounded corner being cut so as to have both a sheared surface and a fractured surface, the sheared surface being adjacent to the first main surface and the fractured surface being adjacent to the second main surface, the lead member having an area ratio of the area of the fractured surface to the total area of the sheared surface and the fractured surface of 0.2 or more and 0.5 or less.

2. The lead member according to claim 1, wherein the area of the sheared surface is larger than the area of the fractured surface.

3. The lead member according to claim 1 or claim 2, wherein a length of the rounded corner along the second direction is longer than a length of the rounded corner along the first direction.

4. The length of the rounded corner along the first direction is 0.1 mm or more and 5.0 mm or less, and the length of the rounded corner along the second direction is 0.5 mm or more and 3.0 mm or less, the lead member according to claim 1 or claim 2.

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