KR100731415B1 - Cap assembly and the rectangular rechargeable battery employing the same - Google Patents

Abstract

The present invention relates to a cap assembly and a rectangular secondary battery employing the same, and more particularly, to improve the cap assembly structure for sealing a case, so that the cap assembly and the electrode tab can be easily and easily combined, that is, separate welding. The present invention relates to a cap assembly having an improved structure that can be combined with a tab without a process or to simplify welding by using a welding method, thereby simplifying a manufacturing process, and a rectangular secondary battery employing the same.

Cap Assembly, Secondary Battery, Tab, Mating

Description

Cap assembly and the rectangular rechargeable battery employing the same

1 is a partial cross-sectional view showing a part of a conventional rectangular secondary battery,

2 is a partial cross-sectional view of a rectangular secondary battery according to an embodiment of the present invention;

3A is an enlarged view of a portion enlarged A of FIG. 2;

3B is a cross-sectional view of A′-A ′ of FIG. 3A;

4A is an enlarged view of a portion enlarged B of FIG. 2;

4B is a cross-sectional view of B′-B ′ of FIG. 4A.

<Description of Symbols for Main Parts of Drawings>

10, 20: rectangular secondary battery 200: cap assembly

210: cap plate 29 29 ': depression

16, 26: positive electrode tab 17, 27: negative electrode tab

The present invention relates to a cap assembly and a rectangular secondary battery employing the same, and more particularly, to improve the cap assembly structure for sealing a case, so that the cap assembly and the electrode tab can be easily and easily combined, that is, separate welding. The present invention relates to a cap assembly having an improved structure that can be combined with a tab without a process or to simplify welding by using a welding method, thereby simplifying a manufacturing process, and a rectangular secondary battery employing the same.

As the weight reduction and high functionality of portable wireless devices such as video cameras, portable telephones, communication PCs, notebook computers, and camcorders have progressed, many studies have been conducted on batteries used as driving power sources. Particularly, rechargeable batteries that can be charged and discharged, for example, lithium secondary batteries are energy per unit weight compared to conventional lead acid batteries, nickel-cadmium (Ni-Cd) batteries, nickel-hydrogen (Ni-MH) batteries, and nickel-zinc batteries. It's about three times the density and allows for fast charging.

The lithium secondary battery can be classified into a liquid electrolyte battery and a polymer electrolyte battery according to the type of electrolyte. Generally, a battery using a liquid electrolyte is called a lithium ion battery and a battery using a polymer electrolyte is called a polymer battery. Lithium secondary batteries can be manufactured in various shapes, and typical shapes include cylindrical, square and pouch types. Particularly, rectangular batteries are very important in lightening and miniaturizing electronic products.

Referring to FIG. 1, the conventional rectangular lithium secondary battery 10 includes a can 11, an electrode assembly 12 accommodated inside the can 11, and a cap assembly 100 coupled to the can 11. ).

The can 11 is a rectangular case, and the electrode assembly 12 has a positive electrode 13, a separator 14, and a negative electrode 15 wound in a jelly-roll type. The positive electrode tabs and the negative electrode tabs 16 and 17 are respectively drawn out from the negative electrode plates 13 and 15.

The cap assembly 100 includes a cap plate 110 coupled to an upper portion of the can 11, an electrode terminal 130 inserted into a through hole of the cap plate 110 through a gasket 120, and Insulating plate 140 is provided on the lower surface of the cap plate 110, and the terminal plate 150 is provided on the lower surface of the insulating plate 140 and is energized with the electrode terminal 130.

An electrolyte injection hole 111 is provided in the cap plate 110 to provide a passage through which the electrolyte is injected into the can 11, and the electrolyte injection hole 111 is sealed by the ball 160.

On the other hand, the can 11 is located in the upper portion of the electrode assembly 12, the insulating case 170 for insulating the electrode assembly 12 and the cap assembly 100 is provided. The insulating case 170 has a tab hole 171 through which the negative electrode tab 17 is drawn out, and an electrolyte inlet hole 172 through which the electrolyte flows.

In this case, the positive electrode tab 16 is directly connected to the bottom surface of the cap plate 110, and the negative electrode tab 17 is electrically connected to the negative electrode terminal 130 through the terminal plate 150. It is.

In the conventional rectangular lithium secondary battery 10 having the structure as described above, the jelly-roll type electrode assembly 12 is inserted into the can 11, and the insulating case 170 is disposed on the upper surface of the electrode assembly 12. )).

The positive electrode tab 16 and the negative electrode tab 17 drawn from the electrode assembly 12 are welded to the bottom surface of the cap plate 110 of the cap assembly 100 and the negative electrode terminal 130, respectively.

Various welding methods are used when welding the positive electrode tab and the negative electrode tab to the cap plate bottom and the negative electrode terminal, respectively, and their common characteristics are to melt and bond the tabs and terminals with resistance heat or a laser beam. However, when the tab is joined to the cap plate or the terminal plate by the welding method, a means for fixing the tab until welding is completed is required separately, and thus there is a problem that the process is complicated and the production speed is reduced.

The present invention is to solve the problems of the above-described rectangular secondary battery, an object of the present invention is to facilitate the coupling of the tab and the cap assembly, to improve the cap assembly of the improved structure that can simplify the manufacturing process and employing the same It is to provide a rectangular secondary battery.

In order to achieve the above object, the present invention

A cap plate having a hole formed in the center;

An electrode terminal crossing the through hole of the cap plate;

Sealing means for sealing the through hole of the cap plate and the electrode terminal;

An insulation plate installed on a lower surface of the cap plate; And

The terminal plate is provided on the lower surface of the insulating plate and the electrode terminal is energized,

It provides a cap assembly characterized in that the depression with the tab is formed on the lower surface of the cap plate.

The depression may be formed in the same direction as the longitudinal direction of the cap assembly or in a vertical direction.

The depression is preferably formed perpendicular to the longitudinal direction of the cap assembly.

The depression has a 10 to 80 ° slope relative to the inlet of the depression.

The depression may be formed in a straight or gentle curve.

A tab is inserted in the recess.

In order to achieve another object of the present invention, the present invention,

An electrode assembly having a positive electrode plate connected with a positive electrode tab, a negative electrode plate connected with a negative electrode tab, and a separator interposed between the positive electrode plate and the negative electrode plate to electrically insulate them;

A can containing the electrode assembly; And

A cap assembly coupled to the top of the can,

The cap assembly includes a cap plate, an insulation plate, and a terminal plate, and provides a rectangular secondary battery including a depression on a bottom surface of at least one of the cap plate and the terminal plate.

A tab is inserted and attached to the recess, and the tab may be a positive electrode tab or a negative electrode tab, and a positive electrode may be inserted into the recessed portion of the lower surface of the cap plate, and a negative electrode tab may be inserted into the recessed portion of the lower surface of the terminal plate.

After the tab is inserted into the recess, a welding process may be further performed.

The depression may be formed in equilibrium or perpendicular to the longitudinal direction of the cap assembly, preferably formed perpendicular to the longitudinal direction.

Hereinafter, a cap assembly according to the present invention and a rectangular secondary battery employing the same will be described in detail with reference to the accompanying drawings.

2 is a partial cross-sectional view of a rectangular secondary battery according to an embodiment of the present invention, FIG. 3A is a partially enlarged view of A of FIG. 2, FIG. 3B is a cross-sectional view of A′-A ′ of FIG. 3A, and FIG. 4A is It is a partial enlarged view of B of FIG. 2, and FIG. 4B is sectional drawing of B'-B 'of FIG. 4A.

Referring to the drawings, the cap assembly 200 is provided with a cap plate 210, the cap plate 210 is a flat metal having a size and shape corresponding to the opening (not shown) of the can. The terminal hole 211 having a predetermined size is formed in the center of the cap plate 210. An electrolyte injection hole 260 is formed at one side of the cap plate 210. The ball 270 is sealably coupled to the electrolyte injection hole 260.

One electrode terminal, for example, a negative electrode terminal 230, may be inserted into the terminal through-hole 211. The outer surface of the negative electrode terminal 230 is provided with a tube-shaped gasket 220 to insulate the cap plate 210. An insulating plate 240 is installed on the lower surface of the cap plate 210. The terminal plate 250 is installed on the bottom surface of the insulating plate 240.

The negative electrode terminal 230 is inserted through the terminal through hole 211 in a state in which the gasket 220 surrounds the outer circumferential surface thereof. The bottom portion of the negative electrode terminal 230 is exposed downward of the cap plate 210 to which the can (not shown) and the cap plate 210 are coupled, and the insulating plate 240 and the terminal plate 250 are interposed therebetween. The position is fixed with respect to the cap plate in the state. The bottom of the negative terminal is electrically connected to the terminal plate 250.

Recesses 29 and 29 are formed on lower surfaces of the cap plate 210 and the terminal plate 250, respectively. The depressions 29, 29 ′ have a slope of 10 ° to 80 ° with respect to the inlet. If the inclination is 10 ° or less, the insertion of the tab is not easy, it is difficult to form the depressions (29, 29 '), and if it is 80 ° or more, there is a fear that the tab can come out again after the tab insertion. The deeper the recess, the narrower it may be.

The depressions 29, 29 ′ may be formed parallel to or perpendicular to the longitudinal direction of the cap assembly 210, but is preferably formed vertically to avoid bending of the tab.

 The cap assembly 200 manufactured as described above may be combined without a welding process when combined with the tabs 26 and 27 drawn out from the electrode assembly (not shown). Since the welding process can be performed immediately, the manufacturing process of the secondary battery can be simplified, resulting in cost reduction.

Hereinafter, a rectangular secondary battery according to an embodiment of the present invention will be described in more detail. 3 is a cross-sectional view of a rectangular secondary battery according to an embodiment of the present invention. Referring to the drawings, the secondary battery includes a can 21, an electrode assembly 22 accommodated in the can 21, and a cap assembly 210 coupled to an upper portion of the can 21.

The can 21 is a rectangular metal material having a rectangular frame shape in which a hollow is formed therein, and may serve as a terminal as it is. The upper portion of the can forms an opening. The bottom surface of the can 21 is provided with a safety plate (not shown) that breaks before other parts when the internal pressure rises due to overcharging of the lithium secondary battery.

The electrode assembly 22 accommodated in the can 21 includes a positive electrode plate 23, a negative electrode plate 25, and a separator 24. The positive and negative plates and the separators 23, 25, and 24 each consist of a single strip, and are arranged in the order of the positive plate, the separator, and the negative plate, and are wound in a jelly-roll type. The separator 24 is interposed between the positive electrode plate and the negative electrode plate to insulate the positive and negative electrode plates 23 and 25.

The positive electrode plate 23 is coated with a positive electrode current collector made of a thin aluminum foil, and a positive electrode active material containing lithium-based oxide as a main component on both surfaces thereof. A positive electrode tab is welded from the positive electrode plate to an area where the positive electrode active material layer of the positive electrode current collector is not coated. An end of the negative electrode tab is also exposed in the upward direction of the electrode assembly.

The separator 24 is composed of polyethylene, polypropylene, a composite film of polyethylene and polypropylene, and it is advantageous to form a wider width than the positive electrode plate and the negative electrode plate to prevent short circuit between the electrode plates.

The secondary battery according to the present invention is manufactured as follows. That is, the electrode assembly 22 is inserted through the opening of the can, and the cap assembly 200 is provided on the top of the can. The cap assembly 200 has a negative terminal 230 interposed on the outer circumferential surface of the gasket 220 is inserted into the cap plate 210 through a terminal through-hole, and an insulating plate 240 and a bottom surface of the cap plate 210. The negative electrode 230 is fixed in a state where the terminal plate 250 is disposed. The negative terminal 230 is electrically connected to the terminal plate 250. At this time, the positive electrode tab 26 is inserted into the recess 29 formed under the cap plate 210 of the cap assembly 200, and the negative electrode tab 27 is provided under the terminal plate 250 of the cap assembly 200. It is inserted into the formed depression 29. This enables attachment of the tab and cap assembly without a separate welding process, which simplifies the process. In addition, when the tab and the cap assembly are to be attached by the welding process, when the tabs 26 and 27 are inserted into the depressions of the cap plate 210 and the terminal plate 250, welding is performed without a separate tab fixing means. It can be performed easily. As a result, the manufacturing process of the rectangular secondary battery can be simplified to speed up the manufacturing process.

The embodiment is an example of a secondary battery employing a cap assembly according to the present invention, a person of ordinary skill in the art to easily manufacture a secondary battery according to the electrode assembly according to the present invention. Can be.

As described above, the cap assembly according to the present invention, unlike the conventional cap assembly to form a depression in the lower cap plate to facilitate the coupling of the tab and the cap assembly, it is possible to attach the tab without a separate welding process, When performing the welding process it is possible to easily perform the welding process without a separate tab fixing means to simplify the manufacturing process of the secondary battery.

Therefore, the secondary battery having the cap assembly according to the present invention can simplify the manufacturing process to obtain a reduction in manufacturing cost.

Claims (8)

A cap plate having a hole formed in the center; An electrode terminal crossing the through hole of the cap plate; A gasket sealing a gap between the through hole of the cap plate and the electrode terminal, and insulating the electrode terminal; An insulation plate installed on a lower surface of the cap plate; And The terminal plate is provided on the lower surface of the insulating plate and the electrode terminal is energized, A depression is formed on the bottom of the cap plate, Wherein the depression is formed in a direction perpendicular to the longitudinal direction of the cap assembly. delete The method of claim 1, Cap recess, characterized in that having a slope of 10 ~ 80 ° relative to the inlet of the depression. An electrode assembly having a positive electrode plate connected with a positive electrode tab, a negative electrode plate connected with a negative electrode tab, and a separator interposed between the positive electrode plate and the negative electrode plate to electrically insulate them; A can containing the electrode assembly; And A cap assembly coupled to the top of the can, The cap assembly includes a cap plate, an insulation plate and a terminal plate, and includes a recess corresponding to a tab on a lower surface of at least one of the cap plate and the terminal plate, Wherein the depression is formed perpendicular to the longitudinal direction of the cap assembly. The method of claim 4, wherein A cathode secondary battery, characterized in that the positive electrode tab is inserted into the depression of the lower surface of the cap plate, the negative electrode tab is inserted into the depression of the lower surface of the terminal plate. The method of claim 5, The secondary battery, characterized in that the welding process is further performed after the tab is inserted into the depression. delete The method of claim 4, wherein A rectangular secondary battery, characterized in that the depression has a slope of 10 ~ 80 ° relative to the inlet of the depression.

Images