KR20080020334A - Rechargeable battery including asymmetric flap type bottom cover - Google Patents

Abstract

A secondary battery equipped with an asymmetric wing-like bottom cover is provided to facilitate insulation and covering of a can type secondary battery, to minimize the thickness of a secondary battery, and to allow the bottom cover to be fixed to a can. A secondary battery equipped with an asymmetric wing-like bottom cover comprises: a bare cell(5) including a cap plate(13) having electrode terminals(9), and a can coupled to the cap plate; a resin molding section(15) formed on a first surface of the bare cell in such a manner that the resin molding section covers the cap plate; and a wing-like bottom cover(1) coupled to a second surface of the bare cell opposite to the first surface. In the secondary battery, the wing-like bottom cover comprises a base portion attached to the second surface, and at least one wing portion extending from the base portion toward the first surface.

Description

Rechargeable Battery Including Asymmetric Flap Type Bottom Cover}

1 is an exploded perspective view of a secondary battery with a wing type hard cover according to the present invention;

Figure 2 is a cross-sectional view showing a cross-section of the bare cell to which the label is attached to explain the overlapping portion of the label.

Figure 3 is an exemplary view for explaining the attachment form of the wing-shaped lower cover according to the present invention.

4A to 4C are exemplary views showing various examples of the winged lower cover.

Figure 5 is a simplified cross-sectional view showing a cross section cut the lower end of the bare cell attached to the wing-shaped hard cover and the label.

Figure 6 is an exploded perspective view of a secondary battery bare cell can be applied to the lower cover according to the present invention.

<Description of the symbols for the main parts of the drawings>

1 wing bottom cover 3 label paper

5, 43: bare cell 7, 21, 69: can

9, 51: electrode terminal 11: gasket

13 cap plate 15 resin molding

17: exposed terminal 19: electrolyte injection hole

23, 41: label sheet 25, 27: overlap

29 lower cover 31 third surface

33a, 35a, 37a: basal plane

33b, 33c, 35b, 35c, 37b, 37c, 45: wing surface

61: gasket 53: cap plate

63: terminal hole 65: electrolyte injection hole

55: insulation plate 57: lead plate

59: cap assembly 87: lead through hole

67: insulation case 77: negative terminal

79: positive terminal 81: insulating tape

71: anode 73: separator

75: cathode 74: electrode assembly

83: adhesive layer 85: lower cover

The present invention relates to a secondary battery, and more particularly to a secondary battery having an asymmetrical wing type hard cover having a lower hard cover to facilitate the insulation and exterior treatment of the can type secondary battery.

A rechargeable battery (rechargeable battery or secondary battery) refers to a battery that can be charged and discharged more than once, unlike primary batteries that are not rechargeable. Such secondary batteries are used in various fields from portable electronic devices such as cellular phones, notebook computers, camcorders, to hybrid vehicles.

In particular, the rechargeable battery using lithium has an operating voltage of 3.6V, which is about three times the operating voltage of a nickel-cadmium (Ni-Cd) battery or a nickel-hydrogen (Ni-MH) battery, which is widely used as a power source for electronic equipment. It is advantageous to apply to more electronic equipment because of its working voltage. In addition, the lithium secondary battery has a high energy density per unit weight, so that it can be manufactured in a small or thin form compared to other batteries, and thus the use field is rapidly increasing and expanding.

The lithium secondary battery generally uses a lithium-based oxide as a cathode active material and a carbon material as a cathode active material. A bare cell is used as a cathode and an anode coated with an active material.

On the other hand, a bare cell manufactured by such a method is rarely directly applied to electronic products, etc., and a packaging process of attaching or forming a case is required to apply the bare cell to other products or to commercialize the bare cell. There are two types of packaging of bare cells, a can type and a pouch type. As a method of packaging, there is a method of using a resin molding and a lower cover.

The outer cover formed through the packaging mainly uses a resin molding cover manufactured using a hot melt resin. This not only can easily form a desired shape according to the mold (or mold), but also has the advantage of tightly sealing a component such as a protective circuit and an electrode terminal. In addition, the hot melt resin itself has excellent insulation properties and does not require a separate insulating material is also a major factor in using the resin molding cover.

In addition to the external cover, the secondary battery used as a product further includes a separate exterior material. Examples of the exterior material include an insulating film for insulation or a label film for describing information and precautions of a product. In particular, in recent years, attempts have been made to minimize the thickness of secondary batteries by adopting a single structure of a label film made of a material having excellent insulating properties, rather than adopting a dual structure of an insulating film and a label film.

However, when the label film is attached to the can type secondary battery, in particular, the square type secondary battery, it is difficult to maintain insulation of the can. A can of a can type secondary battery has a form in which a pair of faces facing each other is wide and a width of a four face that surrounds the shape is relatively narrow, that is, a plate-shaped rectangular parallelepiped. Of course, two of the four surfaces having a narrow width are orthogonal to the wide surfaces and face each other, but are formed to be bent according to the shape of the electrode assembly, but have a very narrow width than the wide surfaces. In particular, the can type secondary can often contacts the positive electrode or the negative electrode of the electrode assembly, and is often used as the positive electrode or the negative electrode. As a result, when the can comes into contact with an external device, an electrical accident such as a short circuit or a short circuit is likely to occur. As a result, the outer surface of the can is wrapped in an outer cover such as a label.

In the method of wrapping the outer surface of the can, a protective circuit or the like is installed on the surface from which the electrode terminal is drawn, and the resin is molded by hot melt resin to form a resin molding part. Then, the exterior member is attached to cover the wider surface of the four surfaces orthogonal to the resin molding. At this time, the exterior material is attached in the form of wrapping the can more than one round. In this case, the surface is not attached to the surface facing the surface on which the resin molding is formed or a process of additionally attaching a separate exterior material is required. To solve this problem, when using an envelope-type exterior material having a shape and size very similar to the shape and size of a can, not only the size and shape are difficult to fit into the can, but also the size and shape of the can can be enclosed in the envelope-type exterior material. There is a problem that it becomes difficult to insert the. In particular, in the case of an envelope-type exterior material, it is almost impossible to use a paper material, and there is also a problem in that a manufacturing cost increases because a resin film having a good tensile property such as vinyl is used.

Accordingly, an object of the present invention is to provide a secondary battery having an asymmetrical wing type lower cover having a lower lower cover to facilitate insulation and exterior treatment of a can type secondary battery.

In addition, another object of the present invention is to provide a secondary battery with an asymmetric wing type lower cover having a wing-shaped fixing portion formed at a portion other than an overlapping portion of the exterior material so as to minimize the thickness of the secondary battery when the can is externally treated.

Lastly, another object of the present invention is to increase the bonding force of the lower lower cover and the can, and also to be asymmetrical to the surface facing the overlapping surface forming surface and the overlapping portion forming surface so as to be firmly fixed by the packaging material. To provide a secondary battery with an asymmetric wing type lower cover to form a wing-shaped fixing portion.

In order to achieve the above object, a secondary battery having a wing-shaped lower cover according to the present invention includes a cap plate on which electrode terminals are formed and a bare cell having a can in which the cap plate is coupled; A resin molding part formed to cover the cap plate on the first surface of the bare cell; And a wing-shaped lower cover coupled to a second surface of the bare cell facing the first surface, wherein the wing-shaped lower cover includes a base attached to the second surface and an extension from the base. At least one wing portion extending in the plane direction is provided.

From the third surface connecting the first surface and the second surface, the label may be further attached to the outer surface of the bare cell to surround the bare cell more than one round.

After attaching the label, the third surface may be formed with a label overlapping portion to which the label is overlapped by one or more layers, and the wing portion may be formed in an area excluding the label overlapping portion.

The label may be attached to the bare cell to surround the wing.

The wing portion may include a first wing portion formed on the third surface, and a second wing portion formed on a fourth surface facing the third surface.

The first wing portion and the second wing portion may be formed in a diagonal direction with respect to the center of gravity of the base portion.

An adhesive layer for adhering the lower cover to the can may be further provided between the base and the can.

The thickness of the wing surface may be a thickness of 85% or more and 115% or less of the label paper thickness.

The thickness of the wing surface may be 0.1mm.

Other features and operations of the present invention in addition to the above objects will become apparent from the detailed description of the embodiments with reference to the accompanying drawings. Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is an exploded perspective view of a secondary battery with a wing-shaped lower cover according to the present invention.

Referring to FIG. 1, a secondary battery having a wing bottom cover according to the present invention includes a bare cell 5, a resin molding part 15, a label paper 3, and a wing bottom cover 1.

The bare cell 5 has a can 7 for accommodating an electrode assembly (not shown) and an electrode terminal 9 on a first surface thereof, and stores and supplies electricity by charging and discharging. Here, the structure and configuration of the bare cell 5 will be described later with reference to FIG. 6. The can 7 of the bare cell 5 is combined with a resin molding 15 including a protection circuit and a wing-shaped lower cover 1, and a label 3 is attached thereto. The first surface of the bare cell 5, that is, the surface from which the electrode terminal 9 is drawn out, is coupled to the cap plate 13 and is formed so as to accommodate a protective circuit connected to the electrode terminal 9 and the cap plate 13. The molding part 15 is formed. In addition, the wing-shaped lower cover 1 is attached to the bottom surface facing the first surface of the bare cell (5).

The resin molding part 15 is formed on the first surface of the bare cell 5, and an exposed terminal 17 is formed to enable connection with an external device. In the resin molding part 15, a protection circuit for connecting the exposed terminal 17 to the electrode terminal 9 and the cap plate 13 of the bare cell 5 is embedded. The resin molding part 15 is formed by inserting a bare cell equipped with a protection circuit into a mold (or a mold) and supplying a hot melt resin. In this case, the resin molding unit 15 surrounds the surface of the can 7 adjacent to the first surface in addition to the first surface, and a part of the resin molding unit 15 is wrapped by the label paper 3. It is attached to the outside of the bare cell (5).

The label paper 3 is attached to the outer surface of the bare cell 5 in order to insulate the bare cell 5 from the outside while the secondary battery information such as the notice of the secondary battery, the manufacturing date, and the manufacturer is described. The label 3 is made of a material such as paper, PET (Poly Ethylene Terephthalate), which is easy to insulate and information. In particular, the label paper 3 is attached to the pillar surface of the bare cell, that is, the third surface that connects the first surface and the bottom surface is wound in the form of one or more turns. That is, in order to increase the adhesive force of the label 3, a portion of the label 3 is attached so as to overlap between the labels 3 at the third side of the bare cell 5. In addition, the label sheet 3 covers the outer surface of the bare cell 5 so as to cover a part of the resin molding part 15 and the wing-shaped lower cover 1, in particular, the wing surfaces 1b and 1c of the wing-shaped lower cover 1. Is attached to. In addition, an adhesive layer for attachment of the label 3 may be further formed on the contact surface between the label 3 and the bare cell 5.

The wing-shaped lower cover 1 is attached for insulation and protection of the bottom surface of the bare cell 5, that is, the third surface, which is not protected by the resin molding 15 and the label paper 3. The wing bottom cover 1 may be manufactured by using a hot melt resin like the resin molding part 15. However, for convenience of the process, the wing bottom cover 1 may be molded and finished by a molding method such as injection or press. Done. To this end, the wing-shaped lower cover 1 has a bottom surface facing the first surface, that is, a base surface 1a attached to the second surface, and wing surfaces 1b and 1c extending from the base surface 1a to the third surface. It is configured to include at least one. In FIG. 1, the wing surfaces 1b and 1c are formed at two positions of the base surface 1a. In addition, the wing surfaces 1b and 1c of the wing-shaped lower cover 1 are not formed on the entire edge of the base surface 1a, and when the wing-shaped lower cover 1 is coupled to the bare cell 5, the label paper It is formed corresponding to the part in which the overlap part of (3) is not formed. The vane lower cover 1 and the wing surfaces 1b and 1c will be described later with reference to FIGS. 2 and 3.

2 is a cross-sectional view showing a cross section of the bare cell to which the label is attached to explain the overlapping portion of the label. In addition, Figure 3 is an exemplary view for explaining the attachment form of the wing-shaped lower cover according to the present invention. In the following description of embodiments of the present invention with reference to FIGS. 2 and 3, descriptions of components other than those related to the description and descriptions on the drawings will be omitted.

Referring to FIG. 2, a form in which a label sheet 23 is wrapped on an outer surface of the can 21 is illustrated. Here, the resin molding portion, the wing-shaped lower cover and other configurations are omitted. When the resin molding part and the wing-shaped lower cover are attached to the bare cell 21, the label paper 23 is attached in the same direction as arrow A of FIG. 2. At this time, the overlapped portion 25 becomes the start point and the end point of the label paper 23 attached. When the label paper 23, which has been started to be attached from the overlapping portion 25, is attached to cover the bare cell 21 by one or more turns, the attachment end point becomes the overlapping portion 25, and the overlapping portion is one layer of labeling paper compared to other portions. Thickened by the thickness of. Even when the label 3 is wrapped in two or more layers, the overlapping portion 25 becomes thicker by the thickness of one layer of the label sheet compared to other places.

Referring to FIG. 3, the hatched portion of FIG. 3 represents the overlapping portion 27, and thus the label sheet is omitted. As can be seen in FIG. 3, the wing surface 29b of the wing-shaped lower cover 29 extends from the base surface 29a to the third surface direction so as to contact the third surface 31 of the bare cell. In this case, when the overlapping part 27 and the wing surface 29b formation position overlap, the part which overlaps by the thickness of the overlapping area 27 and the wing surface 29b becomes thick. Therefore, in the present invention, as shown in FIG. 3, the wing surface 29b is not formed at the portion where the overlapping portion 27 is formed, and the wing surface 29b is formed only at the portion where the label paper does not overlap, thereby resulting in the label attachment. The volume increase of the secondary battery was prevented.

4A to 4C are exemplary views illustrating various examples of the winged lower cover.

4A to 4C, first, as shown in FIG. 4A, a wing-shaped lower cover having wing surfaces 33b and 33c having a shape based on the center of gravity X of the base surface 33a may be used. Can be. In this case, the reason why the lengths of the first wing surface 33b and the second wing surface 33c are the same is to increase convenience when attaching the wing type hard cover to the secondary battery. Of course, the length of the first wing surface 33b and the length of the second wing surface 33c may be different. This is shown in Figure 4b. That is, the wing surface on the side where the overlapping portion is formed is formed like the first wing surface 35b, and the wing surface 35c attached to the surface on which the overlapping portion is not formed is almost equal to the side length of the base surface 35a. You may. However, when the wing surfaces 35b and 35c are formed to have different lengths as described above, the length of the wing surfaces 33b and 33c in consideration of this point is generated because of the inconvenience that they need to be bonded in the direction of attachment to the secondary battery. Must be determined.

In addition, FIG. 4C illustrates a form in which the lengths of the first and second wing surfaces 37b and 37c extend to cover the side surface of the bare cell. Although the wing-shaped lower cover of FIG. 4C has an advantage of being firmly fixed to the lower part of the bare cell, the wing surfaces 37b and 37c are attached by the wing surfaces 37b and 37c at the time of attachment of the label as the length of the wing surfaces 37b and 37c is increased. There is a disadvantage that the resulting label step increases. That is, since the label is attached to cover the wing surfaces 37b and 37c, a stepped step is formed between the label attached to the can and the label covering the wing surfaces 37b and 37c. It may cause label damage. Therefore, the vane type hard cover of FIG. 4C is advantageous to be used in the case of fixing purposes, but it is advantageous to use the vane type hard cover of FIG. 4A in consideration of damage to the label.

FIG. 5 is a cross-sectional view schematically illustrating a cross section of a lower end of a bare cell to which a wing-shaped hard cover and a label are attached.

Referring to FIG. 5, the wing surface 45 of the lower cover is attached to the outer surface of the bare cell 43. Then, the label paper 41 is attached to surround the wing surface 45 and the bare cell 43. Here, the adhesive layer for adhering the label paper 41 is not shown. At this time, the label paper 41 is wound and attached in the form of wrapping the bare cell 43 one or more times to form an overlapping portion. Comparing the thickness of each part of the secondary battery, the thickness of the thinnest part is determined by the label thickness dL. Then, the thickness of the place where the wing surface 45 is located is the thickness as much as the sum of the wing surface thickness (dC) and the label thickness (dL), the thickness (dH) of the overlapping portion is twice the label thickness (dL) do. If the wing surface 45 is formed up to the overlapping portion, since it becomes thicker than the label thickness dL compared to other places, it is preferable that the wing surface 45 is formed to avoid the overlapping portion as in the present invention. In addition, when the wing surface thickness (dC) is approximately equal to the label thickness (dL), the maximum thickness at the time of label application is approximately twice the label thickness (dL), thereby preventing a step between the overlapping portion of the label and another portion. It is possible to reduce the thickness of the secondary battery by the wing surface thickness dC.

The thickness of the label is somewhat different depending on the material used as the label, even if the same label, the thickness is varied depending on the quality, the thickness at the time of the attachment depends on the application state of the adhesive layer. Therefore, it is preferable that the thickness dC of the wing surface has a thickness between 85% and 115% of the label thickness dL. If it is out of the range of 85% to 115%, a step that can be confirmed by the user occurs, and the rate of label damage due to the contact of foreign matters on the stepped part is significantly increased when the secondary battery is used. Based on the actual merchandise, the PET material is molded to a thickness of 0.1 mm to 0.5 mm, and the label material of paper is produced about 0.08 mm to 0.12 mm. Therefore, the wing surface thickness of the wing-shaped lower cover is preferably to have a thickness of about 0.1mm when using a label of paper material.

6 is an exploded perspective view of a secondary battery bare cell to which a lower cover according to the present invention is applicable.

Referring to FIG. 6, the bare cell includes an electrode assembly 74 having lead terminals 79 and 77 of the anode 71 and the cathode 75, and one side is opened and a cavity is formed to accommodate the electrode assembly 74. A cap assembly 59 and an insulating case 67 are coupled to the can 69 and the opening of the can 69.

The can 69 is made of a substantially rectangular parallelepiped columnar container having a cavity, and is mainly manufactured using a deep drawing method. The can 69 accommodates the electrode assembly 74 in the cavity and is coupled to the cap assembly 59 and the insulating case 67 through the opened portion. The material of the can 69 is preferably made of aluminum (Al) or an alloy thereof having excellent mechanical and electrical properties such as heat resistance, abrasion resistance, and electrical conductivity. However, the material may vary depending on the intended use. In addition, the can 69 is in electrical contact with the anode lead terminal 79 and can be used as the anode terminal together with the cap plate 53.

The electrode assembly 74 forms the positive electrode 71 and the negative electrode 75 in the form of a wide plate or metal foil to increase the capacitance, and inserts the separator 73 between the positive electrode 71 and the negative electrode 75. It is used in the form of 'Jelly Roll', which is rolled up in a spiral shape by lamination.

The anode 71 and the cathode 75 are manufactured by coating and drying a slurry on aluminum metal foil and copper metal foil, respectively. At this time, the slurry is composed of a fixing agent for adhering the active material and the split material of each of the positive electrode 71 and the negative electrode 75 to the metal foil. Lithium-containing oxides are mainly used as the positive electrode active material, and carbon materials such as hard carbon, soft carbon, or graphite are mainly used as the negative electrode active material.

The separator 73 is disposed between the positive electrode 71 and the negative electrode 75 to insulate the positive electrode 71 and the negative electrode 75. In addition, the separator 73 provides a passage for ion movement between the anode 71 and the cathode 75. To this end, the separator 73 uses a copolymer of porous polyethylene, polypropylene and polypropylene. It is advantageous to form the separator 73 larger than the width of the anode 71 and the cathode 75 to prevent a short circuit between the anode 71 and the cathode 75.

In addition, the electrode assembly 74 includes a positive electrode lead terminal 79 and a negative electrode lead terminal 77 connected to each of the positive electrode 71 and the negative electrode 75. The positive lead terminal 79 and the negative lead terminal 77 are used as primary conductive paths with an external circuit or device, and are connected to the cap plate 53 and the terminal plate 57 of the cap assembly 59, respectively. do. In addition, the anode and cathode lead terminals 77 and 79 are insulated by an insulating material such as an insulating tape 81 to prevent a short circuit between the electrode plates in a portion exposed to the outside of the electrode assembly 74.

The cap assembly 59 includes a cap plate 53, an electrode terminal 51, an insulating plate 55, and a terminal plate 57.

The cap plate 53 is formed with a terminal through-hole 63 for the passage of the electrode terminal 51 and an electrolyte injection hole 65 for the injection of the electrolyte. The terminal through-hole 63 passes through the electrode terminal 51 with a gasket 61 for insulation therebetween and is connected to the cathode lead-out terminal 77. The cap plate 53 is connected to the anode lead terminal 79 drawn out through the lead through 87 of the insulating case 67 is used as the anode of the bare cell. The electrolyte injection hole 65 is used as a passage for injecting the electrolyte into the can 69 and is sealed after the electrolyte is injected. Here, the electrode connected to the electrode terminal 51 and the electrode connected to the cap plate 53 may be interchanged. The insulation plate 55 is inserted to maintain insulation between the terminal plate 57 and the cap plate 53.

Although not shown in FIG. 6, a protective circuit is attached to an upper portion of the bare cell where the cap assembly 53 and the insulating case 67 are combined, and a resin molding part is formed to cover the protective circuit and the bare cell.

In addition, a wing type lower cover 85 is attached to the bottom surface of the can 69, and an adhesive layer 83 for bonding the can to the wing type lower cover 85 is formed thereon. The adhesive layer 83 may be a liquid adhesive or an adhesive tape. In FIG. 6, the label is omitted, and may be referred to through the description of the above-described embodiment.

As described above, the secondary battery with a wing type hard cover according to the present invention may facilitate the insulation and exterior treatment of the can type secondary battery by providing a wing type lower cover.

In addition, the secondary battery with a wing-shaped lower cover according to the present invention is to form a wing-shaped fixing portion in the portion other than the overlapping portion of the outer packaging material it is possible to minimize the thickness of the secondary battery during the exterior treatment of the can.

Finally, the secondary battery with a wing-shaped lower cover according to the present invention is formed asymmetrically on the surface on which the overlapping portion of the outer surface is formed and the surface facing the overlapping portion formed by forming a wing-shaped fixing portion of the lower lower cover and can In addition to increasing the bonding force, it is possible to firmly secure the lower lower cover by the exterior material.

What has been described above is only one embodiment for explaining the technical idea of the present invention, and the technical scope of the present invention is not limited by the above-described embodiment, but defined by the claims described in the claims of the present invention. Should be. In addition, it will be understood that the present invention may encompass various modifications and equivalent other embodiments that can be made by those skilled in the art.

Claims (9)

A bare cell having a cap plate having an electrode terminal and a can coupled to the cap plate; A resin molding part formed to cover the cap plate on the first surface of the bare cell; It includes a wing-shaped lower cover coupled to the second surface of the bare cell facing the first surface, The wing-shaped lower cover includes a base portion attached to the second surface and at least one wing portion extending from the base portion extending in the first surface direction, characterized in that the wing-shaped lower cover secondary battery. The method of claim 1, And a label sheet attached to an outer surface of the bare cell so as to surround the bare cell one or more times from a third surface connecting the first and second surfaces. The method of claim 2, After the label sheet is attached, the third surface is formed with a label sheet overlapping portion to which the label is attached by overlapping one or more layers, The wing portion is a secondary battery with a wing-shaped lower cover, characterized in that formed in the area excluding the label overlap. The method of claim 3, wherein The label paper secondary battery with a wing-shaped lower cover, characterized in that attached to the bare cell to surround the wing. The method of claim 4, wherein The wing portion, A first wing portion formed on the third surface, The secondary battery with a wing-shaped lower cover, characterized in that it is composed of a second wing formed on the fourth surface facing the third surface. The method of claim 5, wherein The first wing portion and the second wing portion, The secondary battery with a wing-shaped lower cover, characterized in that formed in a diagonal direction with respect to the center of gravity of the base portion. The method of claim 6, The secondary battery having a wing-shaped lower cover, further comprising an adhesive layer between the base and the can to adhere the lower cover to the can. The method of claim 7, wherein The thickness of the wing surface is a secondary battery with a wing-shaped lower cover, characterized in that the thickness of more than 85% to 115% of the thickness of the label. The method of claim 8, The wing-shaped lower cover secondary battery, characterized in that the thickness of the wing surface is 0.1mm.

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