KR20060028188A - Cap assembly and li secondary battery with the same - Google Patents

Abstract

The present invention forms a recess in the lower surface of the terminal plate to accommodate the lower portion of the electrode terminal, thereby reducing the space between the cap assembly and the electrode assembly cap assembly that can improve the battery capacity of the lithium secondary battery and a lithium secondary having the same A battery assembly, the cap assembly of the present invention comprises: a cap plate having a terminal through hole; An electrode terminal inserted into the terminal through hole; And a terminal plate connected to the bottom portion of the electrode terminal, the terminal plate having a through hole corresponding to the terminal through hole, and an electrode terminal accommodating portion to receive the bottom portion of the electrode terminal.

Lithium Secondary Battery, Electrode Terminal, Terminal Plate

Description

Cap assembly and Li secondary battery having the same {Cap Assembly and Li Secondary Battery with the same}

1 is an exploded perspective view for explaining a lithium secondary battery according to an embodiment of the present invention.

Figure 2a is a cross-sectional view for explaining a cap assembly of a lithium secondary battery according to an embodiment of the present invention.

Figure 2b is a plan view for explaining the cap assembly of the lithium secondary battery according to an embodiment of the present invention.

(Explanation of symbols for main parts of drawing)

100; Lithium secondary battery 110; Lithium Secondary Battery Case

200; Electrode assembly 210; First electrode plate

215; First electrode tab 220; Second electrode plate

225; Second electrode tab 230; Separator

240; Insulating tape 300; Cap assembly

310; Cap plate 311; Terminal through hole

312; Electrolyte injection hole 315; Bowl

320; Electrode terminal 330; gasket

340; Insulation plate 350; Terminal plate

355; An electrode terminal accommodating part 360; Insulated case

The present invention relates to a cap assembly and a lithium secondary battery having the same, and more particularly, to form a recess in a lower surface of a terminal plate to accommodate a lower portion of an electrode terminal, thereby reducing the space between the cap assembly and the electrode assembly. The present invention relates to a cap assembly capable of improving battery capacity of a battery and a lithium secondary battery having the same.

Recently, compact and lightweight electric / electronic devices such as cellular phones, notebook computers, camcorders, etc. have been actively developed and produced. These portable electric / electronic devices have a battery pack that can be operated in a place where no separate power source is provided. The built-in battery pack includes at least one battery therein for outputting a predetermined level of voltage for driving the portable electric / electronic device for a period of time.

In view of economical aspects, the battery pack employs a secondary battery capable of charging and discharging. Representative secondary batteries include lithium secondary batteries such as nickel-cadmium (Ni-Cd) batteries, nickel-hydrogen (Ni-MH) batteries, lithium (Li) batteries, and lithium ion (Li-ion) batteries.

In particular, the lithium secondary battery has an operating voltage of 3.6V, which is three times higher than nickel-cadmium batteries or nickel-hydrogen batteries, which are widely used as power sources for portable electronic equipment, and is rapidly expanding in terms of high energy density per unit weight. to be.

Such lithium secondary batteries mainly use lithium-based oxides as positive electrode active materials and carbon materials as negative electrode active materials. In general, a battery is classified into a liquid electrolyte battery and a polymer electrolyte battery according to the type of electrolyte, and a battery using a liquid electrolyte is called a lithium ion battery, and a battery using a polymer electrolyte is called a lithium polymer battery. Moreover, although a lithium secondary battery is manufactured in various shapes, typical shapes include cylindrical shape, square shape, and pouch type.

Typically, the lithium secondary battery is positioned between the positive electrode plate coated with a positive electrode active material, the negative electrode plate coated with a negative electrode active material, and between the positive electrode plate and the negative electrode plate to prevent a short and prevent lithium ion (Li-ion). And an electrode assembly in which a separator capable of moving only is wound, a lithium ion secondary battery case accommodating the electrode assembly, and an electrolyte solution injected into the lithium ion secondary battery case to allow lithium ions to move.

Such lithium secondary batteries are generally manufactured as follows.

First, the positive electrode active material is coated and the positive electrode tab is connected to the positive electrode tab, the negative electrode active material is coated, the negative electrode plate is connected to the negative electrode tab and the separator is laminated, and then wound to prepare an electrode assembly.

Then, the electrode assembly is accommodated in the lithium secondary battery case to prevent the electrode assembly from being separated, and then the cap assembly is combined with the secondary battery case. Thereafter, after the electrolyte is injected into the lithium secondary battery case, the lithium secondary battery is completed by sealing.

On the other hand, the cap assembly of the lithium secondary battery as described above is a cap plate having a terminal through hole, an electrode terminal coupled to the terminal through hole of the cap plate in a state surrounding the outer peripheral portion with a gasket, and coupled with the electrode terminal to the electrode And a terminal plate or the like electrically connected to the assembly.

However, in general, the cap assembly has a structure in which the lower portion of the electrode terminal protrudes out of the terminal plate when the electrode terminal is coupled with the terminal plate. As a result, there is a problem in that the distance between the cap assembly and the electrode assembly is increased.

Therefore, in a current in which the overall height of the lithium secondary battery case is constant, the distance between the cap assembly and the electrode assembly is relatively increased, thereby reducing the battery capacity of the lithium secondary battery.

An object of the present invention is to solve the above problems of the prior art, the present invention forms a recess in the lower surface of the terminal plate to accommodate the lower portion of the electrode terminal, thereby reducing the space between the cap assembly and the electrode assembly lithium secondary An object of the present invention is to provide a cap assembly capable of improving battery capacity of a battery and a lithium secondary battery having the same.

The cap assembly of the present invention for achieving the above object and the cap plate having a terminal through hole; An electrode terminal inserted into the terminal through hole; And a terminal plate connected to the bottom portion of the electrode terminal, the terminal plate having a through hole corresponding to the terminal through hole, and an electrode terminal accommodating portion to receive the bottom portion of the electrode terminal.

In addition, the lithium secondary battery of the present invention includes a wound electrode assembly having a separator interposed between the first electrode plate, the second electrode plate, the first electrode plate and the second electrode plate; A case having a space for accommodating the electrode assembly; A cap assembly including a cap plate having a terminal through hole, an electrode terminal inserted into the terminal through hole, and a terminal plate connected to a bottom portion of the electrode terminal and having an electrode terminal accommodating portion to receive a bottom portion of the electrode terminal. It is provided.

In addition, the manufacturing method of the cap assembly of the present invention includes the steps of inserting the electrode terminal in the terminal through-hole of the assembly of the cap plate; Attaching an insulating plate to a lower surface of the cap plate; Attaching a terminal plate having an electrode terminal accommodating portion to a lower surface of the insulating plate; And plasticizing the bottom portion of the electrode terminal and accommodating the electrode terminal accommodating portion.

In an embodiment of the present invention, the electrode terminal accommodating portion is formed to surround the outside of the through hole.

At this time, it is preferable that the said electrode terminal accommodating part consists of a recessed part.

In addition, the plastic working is a spinning method or a caulking method.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

1 is an exploded perspective view for explaining a lithium secondary battery according to an embodiment of the present invention.

Referring to FIG. 1, a lithium secondary battery 100 according to an embodiment of the present invention includes a secondary battery case 110 and a jelly-roll type electrode assembly 200 accommodated in the secondary battery case 110. And a cap assembly 300 coupled to the upper portion of the secondary battery case 110.

The secondary battery case 110 is made of a metal material having a substantially rectangular shape, and may itself serve as a terminal.

The electrode assembly 200 may be attached to any one of the first electrode tab 215 used as the positive electrode tab and the second electrode tab 225 used as the negative electrode tab, for example, the first electrode tab 215. The second electrode plate 220 to which the first electrode plate 210 and the other one of the first electrode tab 215 and the second electrode tab 225, for example, the second electrode tab 225, are attached. And, the separator 230 interposed between the first electrode plate 210 and the second electrode plate 220 is formed in a wound form, it is accommodated in the secondary battery case 110. have. In order to prevent a short circuit between the first electrode plate 210 and the second electrode plate 220 at the boundary portion at which the first electrode tab 215 and the second electrode tab 225 are drawn out from the electrode assembly 200. Each is insulated by an insulating tape 240.

In addition, the first electrode plate 210 and the second electrode plate 220 may be different from each other, and at least one surface of each of the first electrode plate 210 and the second electrode plate 220 may be a positive electrode active material or a negative electrode. The active material is applied. In this case, a chalcogenide compound is used as the cathode active material, and complex metal oxides such as LiCoO 2, LiMn 2 O 4, LiNiO 2, LiNi 1-x Cox O 2 (0 <x <1), and LiMnO 2 are used. As the negative electrode active material, carbon (C) -based materials, Si, Sn, tin oxides, composite tin alloys, transition metal oxides, lithium metal nitrides, or lithium metal oxides are used. In addition, an electrode plate, for example, the first electrode plate 210, which is used as the anode electrode plate among the first electrode plate 210 and the second electrode plate 220, is made of aluminum (Al) and a cathode electrode plate. The electrode plate used as, for example, the second electrode plate 220 is made of a copper (Cu) material, the separator 230 generally uses polyethylene (PE) or polypropylene (PP), but The invention is not limited to the above materials.

The cap assembly 300 is provided with a flat cap plate 310 having a size and shape corresponding to the opening of the secondary battery case 110. A terminal through hole 311 is formed at the center of the cap plate 310, and an electrolyte injection hole 312 for injecting an electrolyte is formed at one side of the cap plate 310, and the electrolyte injection hole 312 is formed. Coupled with the bowl 315 is sealed. In addition, the cap plate 310 has a protrusion 313 protruding downward.

An electrode terminal 320, for example, a negative electrode terminal, may be inserted into the terminal through hole 311. In addition, the outer surface of the electrode terminal 320 is provided with a tube-shaped gasket 330 for electrical insulation with the cap plate 310. The lower surface of the cap plate 310 is coupled with the projection 313 protruding to the lower portion of the cap plate 310, the through hole corresponding to the terminal through hole 311 attached to the lower surface of the cap plate 310 An insulating plate 340 having 341 is disposed. The lower surface of the insulating plate 340 is provided with a terminal plate 350 having a through hole 351 corresponding to the terminal through hole 311. In addition, the bottom portion of the electrode terminal 320 is electrically connected to the terminal plate 350 in a state of interposing the insulating plate 340. In this case, the terminal plate 350 has a structure including an electrode terminal accommodating part 351 formed of a kind of recessed part for accommodating a bottom portion of the electrode terminal 320. This is for the terminal plate 350 to receive the electrode terminal 320 through the electrode terminal accommodating part 355 to reduce the distance between the cap assembly 300 and the electrode assembly 200.

The first electrode tab 215 drawn from the first electrode plate 210 is welded to the lower surface of the cap plate 310, and the lower end of the electrode terminal 320 is welded from the second electrode plate 220. The drawn second electrode tab 225 is welded.

On the other hand, the upper surface of the electrode assembly 200 electrically insulates the electrode assembly 200 and the cap assembly 300, and at the same time an insulating case 360 that can cover the upper end of the electrode assembly 200 Is installed. The insulating case 360 is provided with an electrolyte injection hole 362 at a position corresponding to the electrolyte injection hole 312 of the cap plate 310, so that the electrolyte can be injected. The insulating case 360 is an insulating polymer resin, preferably made of polypropylene, but the material is not limited in the embodiment of the present invention.

On the other hand, Figure 2a is a cross-sectional view illustrating a cap assembly of a lithium secondary battery according to an embodiment of the present invention, Figure 2b is a plan view for explaining a cap assembly of a lithium secondary battery according to an embodiment of the present invention. .

2A and 2B, a cap assembly 300 of a lithium secondary battery according to an exemplary embodiment of the present invention may include a cap plate 310, an electrode terminal 320, a gasket 330, an insulating plate 340, and a terminal. It is made of a structure having a plate 350. In this case, the cap assembly 300 is the insulating plate 340 and the terminal plate 350 are sequentially attached in the lower direction of the cap plate 310, the terminal through hole 311 of the cap plate 310 The electrode terminal 320 is inserted in the state in which the gasket 330 surrounds the outer circumferential surface thereof.

In addition, the terminal plate 350 includes a through hole 351 corresponding to the terminal through hole 311, and is formed in a shape surrounding the outside of the through hole 351 on the lower surface of the terminal plate 350. The electrode terminal accommodating part 355 may accommodate the bottom portion of the electrode terminal 320.

That is, it is preferable that the said electrode terminal accommodating part 355 consists of a kind of recessed part.

The assembly process of the electrode assembly 300 as described above is as follows.

First, a cap plate 310 having a terminal through hole 311, an electrode terminal 320 inserted into the terminal through hole 311, and insulating the electrode terminal 320 from the cap plate 310 are provided. Prepare the gasket 330.

Then, the electrode terminal 320 is inserted into the terminal through hole 311 while the gasket 330 surrounds the outer circumference of the electrode terminal 320.

After the electrode terminal 320 is inserted into the terminal through hole 311, an insulating plate 340 having a through hole 341 corresponding to the terminal through hole 311 is provided in the lower portion of the cap plate 310. Attach to the face.

After attaching the insulating plate 340 to the lower surface of the cap plate 310, and provided with a through hole 351 corresponding to the terminal through hole 311, the electrode for accommodating the bottom portion of the electrode terminal 320 The terminal plate 350 including the terminal accommodating part 355 is attached to the lower surface of the insulating plate 340.

Thereafter, the bottom surface of the electrode terminal 320 is plastically processed through a spinning method or a caulking method, thereby strengthening the bonding force between the electrode terminal 320 and the terminal plate 350, and A bottom plate of the electrode terminal 320 fills the electrode terminal accommodating part 355 to form a cap plate.

In the lithium secondary battery 100 having the cap assembly 300 as described above, the bottom portion of the electrode terminal 320 does not protrude to the lower portion of the terminal plate 350, and is disposed on the electrode terminal accommodating portion 355. It is formed in a shape that can be relatively close to the distance between the cap assembly 300 and the electrode assembly 200.

Therefore, in a current in which the overall height of the lithium secondary battery case 110 is constant, the distance between the cap assembly 300 and the electrode assembly 200 may be formed relatively close, so that the lithium secondary battery 100 The battery capacity of can be improved.

According to the present invention as described above, the present invention can form a groove in the lower surface of the terminal plate to accommodate the lower portion of the electrode terminal, thereby reducing the space between the cap assembly and the electrode assembly can improve the battery capacity of the lithium secondary battery It is possible to provide a cap assembly and a lithium secondary battery having the same.

While the foregoing has been described with reference to preferred embodiments of the present invention, those skilled in the art will be able to variously modify and change the present invention without departing from the spirit and scope of the invention as set forth in the claims below. It will be appreciated.

Claims (8)

A cap plate having a terminal through hole; An electrode terminal inserted into the terminal through hole; And a terminal plate connected to the bottom portion of the electrode terminal, the terminal plate having a through hole corresponding to the terminal through hole, and an electrode terminal accommodating portion to receive the bottom portion of the electrode terminal. The method of claim 1, The electrode terminal receiving portion cap assembly, characterized in that formed in the form surrounding the outside of the through hole. The method of claim 2, The electrode terminal accommodating portion comprises a recessed portion. A wound electrode assembly having a first electrode plate, a second electrode plate, a separator interposed between the first electrode plate and the second electrode plate; A case having a space for accommodating the electrode assembly; A cap assembly including a cap plate having a terminal through hole, an electrode terminal inserted into the terminal through hole, and a terminal plate connected to a bottom portion of the electrode terminal and having an electrode terminal accommodating portion to receive a bottom portion of the electrode terminal. Lithium secondary battery comprising a. The method of claim 4, wherein The electrode terminal accommodating part is formed in a form surrounding the outside of the through-hole lithium secondary battery. The method of claim 5, The said electrode terminal accommodating part consists of recessed parts, The lithium secondary battery characterized by the above-mentioned. Inserting an electrode terminal into a terminal aperture of the assembly of the cap plate; Attaching an insulating plate to a lower surface of the cap plate; Attaching a terminal plate having an electrode terminal accommodating portion to a lower surface of the insulating plate; And plasticizing the bottom portion of the electrode terminal and accommodating the electrode terminal accommodating portion. The method of claim 7, wherein The plastic working method is a manufacturing method of a cap assembly, characterized in that the spinning (caulking) method or the spinning (caulking) method.

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