Battery and method for manufacturing a battery

Abstract

The objective is to provide a battery that can prevent a portion of the electrode from coming into contact with the edge of the insulating film provided on the outer casing when the electrode is inserted into the outer casing, and a method for manufacturing the same. [Solution] A battery 10 comprising an electrode body 12, an outer casing 20 housing the electrode body 12, and an insulating film 38 disposed between the electrode body 12 and the outer casing 20, wherein the portion of the outer casing 20 where the end portion 38A of the insulating film 38 is located is widened to form an enlarged diameter portion 28 compared to other portions. Furthermore, a method for manufacturing the battery 10 comprising a coating step of applying a volatile solvent to the enlarged diameter portion 28, and a bonding step of attaching the end portion 38A of the insulating film 38 to the solvent-coated portion of the enlarged diameter portion 28.

Description

Technical Field

[0001] The present invention relates to a battery and a method for manufacturing the battery.

Background Art

[0002] A battery having an electrode body inside a can-shaped exterior body has been conventionally known (see, for example, Patent Document 1). This battery has an insulating film between the electrode body and the exterior body.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in such a battery, when the electrode body is inserted into the exterior body, a part of the electrode body may contact the end portion of the insulating film provided on the exterior body, and thus the end portion of the insulating film may be rolled up and bent. If the end portion of the insulating film is rolled up and bent, the insulating property is impaired, and there is a risk of short circuit.

[0005] Therefore, an object of the present invention is to obtain a battery capable of suppressing a part of the electrode body from contacting the end portion of the insulating film provided on the exterior body when the electrode body is inserted into the exterior body, and a manufacturing method thereof.

Means for Solving the Problems

[0006] In order to achieve the above object, a battery according to a first aspect of the present invention includes an electrode body, an exterior body that houses the electrode body, and an insulating film disposed between the electrode body and the exterior body, and a diameter-expanded portion in which a portion of the exterior body where an end portion of the insulating film is disposed is expanded wider than other portions.

[0007] According to the first embodiment of the invention, an insulating film is arranged between the electrode body and the outer casing that houses the electrode body, and the portion of the outer casing where the end of the insulating film is located is an enlarged portion that is wider than other portions. Therefore, when inserting the electrode body into the outer casing, contact between a part of the electrode body and the end of the insulating film provided on the outer casing is suppressed.

[0008] Furthermore, a second embodiment of the battery according to the present invention is a battery according to the first embodiment, wherein the enlarged diameter portion is formed in a tapered shape.

[0009] According to the second embodiment of the invention, the enlarged portion is formed in a tapered shape. Therefore, compared to the case where the enlarged portion is formed in a stepped shape, for example, the insulating film is not bent as much, and the edges of the insulating film are less likely to curl up.

[0010] Furthermore, a third embodiment of the battery according to the present invention is a battery according to the first or second embodiment, wherein the electrode body has terminal portions at both ends in its longitudinal direction, and the longitudinal inner portion of the terminal portion is housed only in the enlarged diameter portion.

[0011] According to the third embodiment of the invention, terminal portions are provided at both ends in the longitudinal direction of the electrode body, and the longitudinal inner portion of the terminal portion is housed only within the enlarged diameter portion. Therefore, compared to the case where the longitudinal inner portion of the terminal portion is housed beyond the enlarged diameter portion, contact between the terminal portion of the electrode body and the end of the insulating film provided on the outer casing is more reliably suppressed or prevented when the electrode body is inserted into the outer casing.

[0012] Furthermore, a fourth embodiment of the present invention is a battery according to the third embodiment, wherein the electrode body has a current collecting foil portion between the electrode body portion and the terminal portion, and the enlarged diameter portion is formed outside the longitudinal middle portion of the current collecting foil portion.

[0013] According to the fourth aspect of the invention, the electrode body has a current-collecting foil portion between the electrode body portion and the terminal portion, and an enlarged diameter portion is formed outside the longitudinal middle portion of the current-collecting foil portion. Therefore, the electrode body portion is effectively constrained by the outer casing.

[0014] Furthermore, the fifth embodiment of the present invention is a battery according to any one of the first to fourth embodiments, wherein the electrode body is a solid-state battery having a solid electrolyte in the electrolyte layer.

[0015] According to the fifth aspect of the invention, the electrode body is a solid-state battery having a solid electrolyte in the electrolyte layer. Here, since a solid-state battery requires a higher confinement pressure than a liquid-system battery, the electrode body needs to be strongly confined by the outer casing. The outer casing can secure a large area in close proximity to the electrode body, making it easy to apply the confinement pressure.

[0016] Furthermore, a sixth embodiment of the present invention is a method for manufacturing a battery according to any one of the first to fifth embodiments, comprising: a coating step of applying a volatile solvent to the enlarged diameter portion; and a bonding step of attaching the end of the insulating film to the solvent-coated portion of the enlarged diameter portion.

[0017] According to the sixth embodiment of the invention, a volatile solvent is applied to the enlarged diameter portion, and the end of an insulating film is attached to the solvent-coated portion of the enlarged diameter portion. Therefore, the end of the insulating film is held in place by the enlarged diameter portion of the outer casing, preventing the end of the insulating film from curling up when the electrode body is inserted into the outer casing. [Effects of the Invention]

[0018] As described above, according to the present invention, it is possible to suppress contact between a part of the electrode body and the edge of the insulating film provided on the outer casing when the electrode body is inserted into the outer casing. [Brief explanation of the drawing]

[0019] [Figure 1] This is a schematic perspective view showing the battery according to this embodiment. [Figure 2] It is a schematic perspective view showing the electrode body of the battery according to this embodiment. [Figure 3] It is a schematic perspective view showing the exterior body of the battery according to this embodiment. [Figure 4] It is a schematic perspective view showing the lid of the battery according to this embodiment. [Figure 5] It is a schematic cross-sectional view showing the internal structure of the battery according to this embodiment. [Figure 6] It is a schematic side cross-sectional view showing an enlarged diameter portion of the battery according to this embodiment.

Mode for Carrying Out the Invention

[0020] Hereinafter, embodiments of the present invention will be described in detail based on the drawings. For convenience of explanation, in each figure, the arrow UP shown as appropriate is the upward direction of the battery, the arrow FR is the front direction of the battery, and the arrow LH is the left direction of the battery. Therefore, in the following description, when the directions of up and down, front and back, and left and right are described without special mention, they indicate up and down, front and back, and left and right in the battery, but are not particularly limited to these directions.

[0021] As shown in FIG. 1, the battery 10 according to this embodiment is a all-solid-state battery, and includes an electrode body 12 shown in FIG. 2, an exterior body 20 shown in FIG. 3 that houses the electrode body 12, and a lid 30 shown in FIG. 4 that closes the upper end portion of the exterior body 20 that houses the electrode body 12 (the end portion on the side opposite to the bottom wall 22 described later). Note that the exterior body 20 and the lid 30 are formed of a metal such as an aluminum alloy. Also, the lid 30 can be regarded as a part of the exterior body 20.

[0022] As shown in Figure 2, the electrode body 12 has an electrode body portion 14 formed in a substantially rectangular parallelepiped shape with the front-to-back direction as the thickness direction and the left-to-right direction as the longitudinal direction, current collecting foil portions 16 provided on both the left and right sides of the electrode body portion 14, and terminal portions 18 provided on the left and right outer sides of the current collecting foil portion 16. In other words, the electrode body 12 has a current collecting foil portion 16 between the electrode body portion 14 and the terminal portion 18, and the electrode body portion 14 and the terminal portion 18 (plate portion 18A described later) are electrically connected by the current collecting foil portion 16.

[0023] The electrode body portion 14 has a solid electrolyte in its electrolyte layer, and the terminal portions 18 provided at both longitudinal ends of the electrode body 12 have a metal plate portion 18A that is electrically connected to the electrode body portion 14. The plate portion 18A is formed in a substantially rectangular flat plate shape with the vertical direction as its longitudinal direction, and its outer shape is larger than the left and right sides of the electrode body portion 14 and the current collector foil portion 16. Specifically, this plate portion 18A is formed to a size that can close the opening 28A in the enlarged diameter portion 28 of the outer casing 20, which will be described later.

[0024] Furthermore, a pair of electrode terminals 18C, having a predetermined protruding height and forming a substantially square shape when viewed from the left and right directions, are integrally formed on the outer surface of the plate portion 18A that constitutes the terminal portion 18, at a predetermined interval in the vertical direction. In addition, a resin insulating portion (insulator) 18B, having an outer diameter slightly smaller than that of the plate portion 18A, is integrally provided on the inner surface of the plate portion 18A that constitutes the terminal portion 18, and the insulating portion 18B is configured to be housed only within the enlarged diameter portion 28 (without exceeding the enlarged diameter portion 28), which will be described later.

[0025] As shown in Figure 3, the outer casing 20 is can-shaped and has a rectangular flat bottom wall 22 with the left-right direction as its longitudinal direction, and a pair of rectangular flat main walls 24 that are integrally erected at a predetermined height on the long sides of the bottom wall 22. The upper ends of the pair of main walls 24 (the ends opposite to the bottom wall 22) each have an integrally formed overhang 26 that protrudes toward each other, and the overhang lengths of the overhangs 26 toward each other are the same. As a result, the narrow portion 32 of the lid 30 that seals the upper end of the outer casing 20, which will be described later, is positioned in the center of the upper end in the front-rear direction.

[0026] Furthermore, widened diameter portions 28 are formed at both ends in the left-right direction of the outer casing 20 (bottom wall 22, main body wall 24, and protruding portion 26), which are wider than other parts. As shown in detail in Figure 6, the widened diameter portion 28 is formed in a tapered shape that gradually widens from the middle part (approximately the center in the left-right direction) of the current collector foil portion 16 when viewed from the front-rear direction, and the left-right outer ends of the widened diameter portion 28 are designated as openings 28A.

[0027] As shown in Figure 4, the lid 30 is formed in a "convex" shape with a narrow section 32 and a wide section 34 at the top and bottom when viewed in cross-section from the left and right directions. As shown in Figure 5, the width of the wide section 34 that constitutes the lower part of the lid 30 along the front-to-back direction is the same as the distance between the pair of main body walls 24, and the narrow section 32 that constitutes the upper part of the lid 30 is formed in the center of the wide section 34 in the width direction (front-to-back direction).

[0028] In other words, half the difference between the width of the wide section 34 and the width of the narrow section 32 is the same as the overhang length of the overhang section 26, and when the lid 30 is installed on the upper end of the outer casing 20 (between the upper ends of the pair of main body walls 24), the narrow section 32 is held in place by the overhang section 26 from the front and rear directions. In other words, the overhang section 26 fits into the stepped section 36 formed by the narrow section 32 and the wide section 34, and the upper surface (outer surface) of the narrow section 32 and the upper surface (outer surface) of the overhang section 26 are flush.

[0029] In this state, the lid 30 is joined to the upper end of the outer casing 20 by welding, thereby sealing the upper end. The left and right ends 30A of the lid 30 are shaped to match the shape of the enlarged diameter portion 28 of the outer casing 20, and are angled upward as they extend outward in the left and right directions, with their width gradually increasing as they extend outward in the left and right directions.

[0030] As shown in Figure 5, the inner surface (upper surface) of the bottom wall 22 of the outer casing 20, the inner surface of the main body wall 24, and the inner surface (lower surface of the wide portion 34) of the lid 30 are each covered with an insulating film 38 that extends over almost the entire surface. In other words, the insulating film 38 is positioned between the electrode body 12 and the outer casing 20 (including the lid 30). This insulating film 38 is made of, for example, an unoriented polypropylene (CPP) resin material and is formed to a predetermined thickness.

[0031] Furthermore, as shown in Figure 6, the portion of the outer casing 20 where the end portion 38A of the insulating film 38 is located is defined as the enlarged diameter portion 28. In other words, the length of the insulating film 38 is set so that the end portion 38A of the insulating film 38 is located in the enlarged diameter portion 28. The end portion 38A of the insulating film 38 is then attached to the inner surfaces of both the left and right ends of the bottom wall 22 and the main body wall 24 that constitute the enlarged diameter portion 28 (hereinafter referred to as the "inner surfaces of the enlarged diameter portion 28") as follows.

[0032] Specifically, a highly volatile solvent such as alcohol is applied to the inner surface of the enlarged diameter portion 28, and the surface tension (intermolecular forces) of the solvent adheres the end portion 38A of the insulating film 38 to the inner surface of the enlarged diameter portion 28. As a result, the end portion 38A of the insulating film 38 is held against the inner surface of the enlarged diameter portion 28, preventing it from curling up.

[0033] The operation (manufacturing method) of the battery 10 according to this embodiment, which has the configuration described above, will now be explained.

[0034] First, an insulating film 38 is attached to the inner surface of the bottom wall 22 and the inner surface of the main body wall 24 of the outer casing 20. In the outer casing 20, the portion where the end portion 38A of the insulating film 38 is placed is an enlarged diameter portion 28 that is wider than other portions. When attaching the end portion 38A of the insulating film 38 to the inner surface of the enlarged diameter portion 28, a highly volatile solvent such as alcohol is applied to the inner surface of the enlarged diameter portion 28 (coating step). Then, the end portion 38A of the insulating film 38 is attached to the solvent-coated portion on the inner surface of the enlarged diameter portion 28 (attachment step). As a result, the end portion 38A of the insulating film 38 is held on the inner surface of the enlarged diameter portion 28.

[0035] After attaching the insulating film 38 to the inner surface of the bottom wall 22 and the inner surface of the main body wall 24 of the outer casing 20, the protruding portions 26 of the outer casing 20 are moved in a direction that separates them from each other to widen the upper end of the outer casing 20, and the electrode body 12 is inserted into the widened upper end of the outer casing 20 from above. Then, the lid 30 is inserted into the upper end of the outer casing 20 in which the electrode body 12 is inserted (housed). Note that the insulating film 38 has been attached in advance to the lower surface of the wide portion 34 of the lid 30.

[0036] After inserting the cover 30 onto the upper end of the outer casing 20 (above the electrode body 12), the protruding portions 26 are moved toward each other to clamp the narrow portion 32 of the cover 30 with the protruding portions 26, and the cover 30 is joined to the upper end of the outer casing 20 by welding, thereby sealing the upper end of the outer casing 20. Then, the insulating portion 18B of the terminal portion 18 is inserted into the enlarged diameter portion 28, and the opening 28A is closed by the plate portion 18A of the terminal portion 18.

[0037] Here, the end portion 38A of the insulating film 38 is held on the inner surface of the enlarged diameter portion 28. Therefore, when the electrode body 12 is inserted into the outer casing 20, that is, when the insulating portion 18B of the terminal portion 18 is inserted into the enlarged diameter portion 28, it is possible to prevent the end portion 38A of the insulating film 38 from curling up, and it is also possible to suppress or prevent the insulating portion 18B of the terminal portion 18 from coming into contact with the end portion 38A of the insulating film 38. Thus, when the insulating portion 18B is inserted into the enlarged diameter portion 28, it is possible to suppress or prevent the end portion 38A of the insulating film 38 from curling up and bending.

[0038] In particular, since the insulating portion 18B in this terminal portion 18 is configured to be housed only in the enlarged diameter portion 28, it is possible to more reliably suppress or prevent contact with the end portion 38A of the insulating film 38 compared to when it is housed beyond the enlarged diameter portion 28. Therefore, it is possible to more reliably suppress or prevent the end portion 38A of the insulating film 38 from curling and bending when the insulating portion 18B is inserted into the enlarged diameter portion 28.

[0039] In this way, once the opening 28A is closed by the plate portion 18A of the terminal portion 18, the peripheral portion on the inner surface of the plate portion 18A of the terminal portion 18 is welded to the left and right edges of the bottom wall 22 and the main body wall 24 (including the protruding portion 26) that constitute the opening 28A. As a result, the opening 28A in the enlarged diameter portion 28 of the outer casing 20 is sealed by the plate portion 18A of the terminal portion 18, and a battery 10 as shown in Figure 1 is manufactured. Thus, according to this embodiment, a battery 10 that is not at risk of short-circuiting can be stably produced.

[0040] Furthermore, when viewed from the front or back, the enlarged diameter portion 28 is formed in a tapered shape. Therefore, compared to the case where the enlarged diameter portion 28 is formed in a stepped shape, for example, the insulating film 38 is not bent significantly (at approximately a right angle), and the end portion 38A of the insulating film 38 is less likely to curl up (less likely to peel off from the inner surface of the enlarged diameter portion 28). Thus, it is possible to further prevent the end portion 38A of the insulating film 38 from curling up.

[0041] Furthermore, the enlarged diameter portion 28 that accommodates the insulating portion 18B of the terminal portion 18 is formed outside the midpoint in the left-right direction of the current collector foil portion 16. Therefore, the electrode body portion 14 can be effectively restrained by the outer casing 20. In addition, this allows the electrode body portion 14 and the insulating film 38 to be in close contact, thereby effectively insulating the outer casing 20 from the electrode body 12 while suppressing a reduction in the volumetric energy density of the electrode body portion 14.

[0042] Furthermore, the battery 10 according to this embodiment is a solid-state battery in which the electrode body 12 (electrode main body portion 14) has a solid electrolyte in the electrolyte layer. Here, since a solid-state battery requires a higher constraining pressure than a liquid-type battery, the electrode body 12 needs to be strongly constrained by the outer casing 20. As described above, the outer casing 20 in this embodiment can secure a large area that is in close proximity to the electrode body 12 (electrode main body portion 14), so that the constraining pressure can be easily applied. Note that the "solid-state battery" in this embodiment is not limited to an all-solid-state battery, but may also be a semi-solid-state battery (containing a solid electrolyte and a gel or polymer in the electrolyte layer).

[0043] The battery 10 and its manufacturing method according to this embodiment have been described above based on the drawings. However, the battery 10 and its manufacturing method according to this embodiment are not limited to those shown, and can be modified as appropriate without departing from the spirit of the present invention. For example, the length in the left-right direction, the length in the up-down direction (height), and the length in the front-back direction (thickness) of the battery 10 are not limited to the lengths shown.

[0044] Furthermore, the width (length) of the narrow portion 32 of the lid 30 along the front-rear direction and the overhang length of the protruding portion 26 of the outer casing 20 are exaggerated in each figure and are not limited to the lengths shown. Therefore, for example, the width (length) of the narrow portion 32 along the front-rear direction may be twice or more the overhang length of the protruding portion 26.

[0045] Furthermore, the angle of expansion (taper angle) and shape of the enlarged diameter portion 28, the thickness of the insulating film 38, etc., are exaggerated in each figure and are not limited to the angles, shapes, thicknesses, etc. shown. Also, the enlarged diameter portion 28 is not limited to being formed in a tapered shape; it may be formed in a stepped shape, for example, as long as the end portion 38A of the insulating film 38 is less likely to curl up. [Explanation of symbols]

[0046] 10 batteries 12 Electrode body 14 Electrode body 16 Current collector foil section 18 Terminal section 20 Exterior 28 Expanded diameter part 38 Insulating film 38A end

Claims

1. Electrode body and An outer casing for housing the electrode body, An insulating film is disposed between the electrode body and the outer casing, Equipped with, A battery in which the portion of the outer casing where the end of the insulating film is located is an enlarged portion that is wider than other portions.

2. The battery according to claim 1, wherein the enlarged diameter portion is formed in a tapered shape.

3. The electrode body has terminal portions at both ends in its longitudinal direction. The battery according to claim 1, wherein the longitudinal inner portion of the terminal portion is housed only in the enlarged diameter portion.

4. The electrode body has a current-collecting foil portion between the electrode body portion and the terminal portion. The battery according to claim 3, wherein the enlarged diameter portion is formed outside the midpoint portion in the longitudinal direction of the current collector foil portion.

5. The battery according to claim 1, wherein the electrode body is a solid battery having a solid electrolyte in the electrolyte layer.

6. A method for manufacturing a battery according to any one of claims 1 to 5, A coating step of applying a volatile solvent to the enlarged diameter portion, A bonding step of attaching the end of the insulating film to the solvent-coated portion in the enlarged diameter portion, A method for manufacturing a battery having [a certain characteristic].

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