KR100670452B1 - Electrode assembly and the same using Secondary Battery - Google Patents

Abstract

In the secondary battery according to the present invention, an electrode assembly including an auxiliary insulator at an interface between the first and second electrode plates and the separator is laminated and wound, and the case and the case accommodating the electrode assembly are sealed. Since the cap assembly includes a cap assembly configured to be finished, the first and second electrode plates are prevented from being short-circuited by the auxiliary insulator even if the separator is damaged or deformed by the heat generated during the charging / discharging of the secondary battery.

Secondary Battery, Electrode Assembly, Separator Damage

Description

Electrode assembly and secondary battery using same

1 is an exploded perspective view showing an embodiment of an electrode assembly according to the present invention;

2 is an exploded perspective view showing another embodiment of an electrode assembly according to the present invention;

3 is a view illustrating an embodiment of a secondary battery to which an electrode assembly according to the present invention is applied.

<Brief Description of Major Codes in Drawings>

100: secondary battery 110: case

200 electrode assembly 210 first electrode plate

210a: first electrode current collector 211: first active material layer

213: first uncoated portion 215: first electrode tab

220: second electrode plate 220a: second electrode current collector

221: second active material layer 223: second uncoated portion

225: second electrode tab 230: separator

250: auxiliary insulator

300: Cap Assembly

310: cap plate 311: first terminal through

321: electrolyte injection hole 315: bowl

320: electrode terminal 330: gasket

340: insulating plate 341: second terminal through

350: terminal plate 351: third terminal through

360: Insulation Case

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a secondary battery, and relates to a secondary battery including an electrode assembly on which first and second electrode plates and a separator are wound.

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 consideration of economical aspects, battery packs employ secondary batteries that can be charged and discharged in recent years. 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 3.6 V, which is three times higher than that of a nickel-cadmium battery or a nickel-hydrogen battery, which is widely used as a power source for portable electronic equipment, and is rapidly increasing 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.

In general, a lithium secondary battery is positioned between a positive electrode plate coated with a positive electrode active material, a negative electrode plate coated with a negative electrode active material, and a positive electrode plate and a negative electrode plate to prevent a short and to move only lithium ions (Li-ion). The electrode assembly which enables the separator to be wound up, the lithium secondary battery case which accommodates an electrode assembly, and the electrolyte solution injected into the lithium secondary battery case inside, and enable movement of lithium ion etc. are comprised.

In the secondary battery configured as described above, ions emitted from the positive electrode plate made of aluminum are moved to the negative electrode plate made of copper during charge / discharge, and at this time, heat is generated in the electrode assembly so that the internal temperature is about 150 ° C. do.

However, such a conventional secondary battery has a problem that the separator is damaged or deformed by heat generated during charging / discharging.

That is, the separator shrinks due to high heat, and the length thereof becomes short, and the electrode plate made of aluminum and the electrode plate made of copper are brought into contact with each other and short-circuited.

The present invention has been made to solve the above problems, an object of the present invention is an electrode assembly to prevent the separator interposed between the first and second electrode plate to prevent the short circuit of the electrode plate and a secondary battery using the same To provide.

The present invention for achieving the above object is formed of a metal material, between the first and second electrode plate and the first and second electrode plate comprising a portion coated with the active material layer, the non-coating active material layer, and the first and second electrode plate Provided is an electrode assembly including a separator interposed therebetween and an auxiliary insulator disposed between the separator and the first and second electrode plates to insulate the first and second electrode plates.

The auxiliary insulator preferably has a heat deflection temperature of 150 ° C or higher.

The auxiliary insulator may be installed on the first and second electrode plates.

Only one of the first and second electrode plates may be installed, and only the uncoated portion of the first and second electrode plates may be installed.

The auxiliary insulator is preferably provided on both sides of the separator.

The auxiliary insulator is installed on the separator facing the uncoated portion and may be installed only on one surface of the separator.

The auxiliary insulator may have a paste shape and may be applied to the separator or the first and second electrode plates.

The auxiliary insulator may be a tape having an adhesive on at least one surface.

The auxiliary insulator is preferably formed of a material that can transmit the electrolyte solution.

The tape is formed of a polyolefin-based material except polyethylene, and may be formed of any one of polyimide (PI), polypropylene (PP), and polyethylene terephthalate (PET).

The first electrode plate may be a cathode.

In addition, the first and second electrode plates and separators are stacked and wound, and an electrode assembly including an auxiliary insulator at an interface between the first and second electrode plates and the separator, a case accommodating the electrode assembly, and a seal to close the case. It provides a secondary battery comprising a cap assembly.

The auxiliary insulator preferably has a heat deflection temperature of 150 ° C or higher.

The case may be formed in a square or pouch form and may be formed in a cylindrical shape.

Hereinafter, with reference to the drawings will be described in detail a preferred embodiment of a secondary battery according to the present invention.

1 is an exploded perspective view showing an embodiment of the electrode assembly according to the invention, Figure 2 is an exploded perspective view showing another embodiment of the electrode assembly according to the invention, Figure 3 is an electrode assembly according to the invention FIG. 1 illustrates an embodiment of an applied secondary battery. FIG.

Referring to these drawings, the lithium secondary battery is made of a jelly-roll-type electrode assembly 200 is received in the case 110, the electrolyte is injected and finished with a cap assembly 300.

The secondary battery case 110 is made of a metal material, and may itself serve as a terminal. Here, the case 110 may be formed in a cylindrical shape, a square shape, or a pouch type.

The electrode assembly 200 includes a first electrode plate 210 having a first electrode tab 215, a second electrode plate 220 having a second electrode tab 225, and the first electrode plate 210. ) And the first and second separators 230 and 240 interposed between the second electrode plate 220 and the second electrode plate 220.

That is, in the electrode assembly 200, the first electrode plate 210, the second electrode plate 220, and the first and second separators 230 and 240 each consist of one strip, and thus, the first separator 230, The first electrode plate 210, the second separator 240, and the second electrode plate 220 are disposed in this order and wound in a jelly-roll type.

The first electrode plate 210 may be an anode, and the first active material layer 211 may be formed on the first electrode current collector 210a formed of a thin metal plate having excellent conductivity, for example, aluminum (Al) foil. It is made by coating. As the active material, a chalcogenide compound is used. For example, 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. It is not limited. Both ends of the first electrode plate 210 are regions of the first electrode current collector 210a to which the first active material layer 211 is not coated, that is, the first electrode uncoated portion 213 and the first electrode uncoated portion ( The first electrode tab 215 is electrically connected to any one of the 213.

The second electrode plate 220 may be a cathode, and a second electrode current collector 220a made of a conductive metal plate, for example, copper (Cu) or nickel (Ni) foil, and a second coated on both surfaces thereof. The active material layer 221 is included. The second active material may be a carbon (C) -based material, Si, Sn, tin oxide, composite tin alloys, transition metal oxides, lithium metal nitrides, or lithium metal oxides. It is not limited. Both ends of the second electrode plate 220 are regions of the second electrode current collector 220a in which the second active material layer 221 is not formed, that is, the second electrode uncoated portion 223, and the second electrode uncoated portion 223. ), For example, the second electrode tab 225 is electrically connected to the second electrode uncoated portion 223 on the opposite side where the first electrode tab 215 of the first electrode plate 210 is formed. have.

The first and second separators 230 and 240 prevent short of the first electrode plate 210 and the second electrode plate 220 and charge the lithium secondary battery 100, for example, lithium ions. It is possible to move only, and is made of any one selected from the group consisting of polyethylene, polypropylene, and a copolymer (co-polymer) of polyethylene and polypropylene, but the material is not limited in this embodiment. . The separator 230 may be formed to be wider than the first electrode plate 210 and the second electrode plate 220 to prevent a short circuit between the first electrode plate 210 and the second electrode plate 220. .

In this case, the first and second separators 230 and 240 may be formed of a material having a heat deformation temperature of 150 ° C. or more, which is deformed by damage such as shrinkage due to heat, so that the first and second separators 230 and 240 may not be deformed even when heat is generated during charging / discharging of the secondary battery 100.

On the other hand, the material of the first and second separators 230 and 240 is an auxiliary insulator 250 between each of the first and second electrode plates 210 and 220 and the first and second separators 230 and 240 if the thermal deformation temperature is less than 150 ° C. Is installed.

The auxiliary insulator 250 is the first electrode plate 210 and the second electrode when the first and second separators 230 and 240 are deformed or damaged by melting or shrinking due to heat generated during charging / discharging of the secondary battery 100. It is for preventing the plate 220 from contacting and short-circuiting. Therefore, since the heat generated during charging / discharging of the secondary battery 100 is 150 ° C. or more, the auxiliary insulator preferably has a heat deformation temperature of 150 ° C. or more.

In addition, the auxiliary insulator 250 is preferably formed of a material that allows the electrolyte to permeate so that the secondary battery can be charged / discharged.

Accordingly, the auxiliary insulator 250 is preferably a polyolefin series except for polyethylene that is modified at 150 ° C. or less, and may be formed of any one of polyimide (PI), polypropylene (PP), and polyethylene terephthalate (PET). However, it is not limited to those mentioned above.

The auxiliary insulator 250 may be installed on one surface of the first electrode plate 210 and the second electrode plate 220, and may be installed only on one of the first electrode plate 210 and the second electrode plate 220. It may be. For example, even if the auxiliary insulator 250 is installed only on the first electrode plate 210, when the first and second separators 230 and 240 are deformed, the auxiliary insulator 250 is prevented from contacting the second electrode plate 220 and short-circuited. to be.

In addition, the auxiliary insulator 250 may be installed on the first and second plain portions 213 and 223 of the first and second electrode plates 210 and 220, respectively. That is, in the auxiliary insulator 250, even when the first and second separators 230 and 240 are deformed to contact the first and second electrode plates 210 and 220, the portion where the first and second active material layers 211 and 221 are coated is not short-circuited. However, since the first and second electrode current collectors 210a and 220a are formed of aluminum foil and copper foil, respectively, the first and second non-coating parts 213 and 223 to which the first and second active material layers 211 and 221 are not applied are formed. When contacted, a short circuit occurs. Therefore, the auxiliary insulator 250 may be provided only at the first and second plain parts 213 and 223 or at both ends of the first uncoated part 213 or the second electrode plate 220 formed at both ends of the first electrode plate 210. It may be provided only in the formed second uncoated portion 223.

The auxiliary insulator 250 may be installed in the first and second separators 230 and 240.

One surface of the first separator 230 contacts the first electrode plate 210, and the other surface of the second separator 240 contacts the other surface of the first electrode plate 210, and the other surface of the first separator 230 contacts the second electrode plate 220. The interposed between the first electrode plate 210 and the second electrode plate 220 to be in contact with one surface of the. Here, the auxiliary insulator 250 may be installed only on one surface of each of the first and second separators 230 and 240. That is, the first and second separators 230 and 240 may prevent the short circuit of the first and second electrode plates 210 and 220 by the auxiliary insulator 250 even when the second and second separators 230 and 240 are deformed and contracted during charging / discharging of the secondary battery 100.

Meanwhile, the auxiliary insulator 250 may be formed in a paste form and applied to the first and second electrode plates 210 and 220 or the first and second separators 230 and 240. In addition, the auxiliary insulator 250 may be formed in the form of a tape having an adhesive on at least one surface thereof and adhered to the first and second electrode plates 210 and 220 or the first and second separators 230 and 240.

As described above, when the electrode assembly 200 is accommodated in the rectangular case 110, the electrode assembly 200 is closed by the cap assembly 300 as shown in FIG. 3.

The cap assembly 300 is provided with a flat cap plate 310 having a size and a 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. ) Is combined with the bowl 315 and sealed.

An electrode terminal 320, for example, a negative electrode terminal, may be inserted into the terminal through hole 311. The outer surface of the electrode terminal 320 is provided with a tube-shaped gasket 330 for electrical insulation with the cap plate 310. An insulation plate 340 is disposed on the bottom surface of the cap plate 310. The terminal plate 350 is installed on the bottom surface of the insulating plate 340.

The electrode terminal 320 is inserted through the terminal through hole 311 while the gasket 330 surrounds the outer circumferential surface. 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.

A positive electrode tab 215 drawn from the positive electrode plate 210 is welded to a lower surface of the cap plate 310, and a negative electrode tab drawn from the negative electrode plate 220 is attached to a lower end of the electrode terminal 320. 225 is welded.

An insulating case 360 is provided on the upper surface of the electrode assembly 200 to electrically insulate the electrode assembly 200 from the cap assembly 300, and at the same time to cover the upper end of the electrode assembly 200. have. 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.

Therefore, the secondary battery is prevented from shorting the first and second electrode plates 210 and 220 by the auxiliary insulator 250 even when the first and second separators 230 and 240 are damaged by the heat generated during the charging / discharging.

Meanwhile, the jelly-roll electrode assembly 200 may be accommodated in a cylindrical case or pouch-shaped case (not shown) and formed as a secondary battery 100.

According to the present invention, the secondary battery has an advantage of preventing the first and second electrode plates from being short-circuited by the auxiliary insulator even if the separator is damaged or deformed by the heat generated during charging / discharging.

In addition, the secondary battery has an advantage that its life is long as the short circuit of the first and second electrode plates is prevented.

Claims (21)

delete First and second electrode plates formed of a metal material and including a portion coated with an active material layer and an uncoated portion not coated with the active material layer; A first separator interposed between the first electrode plate and the second electrode plate and in contact with both surfaces of the first and second electrode plates; A second separator disposed outside the second electrode plate and in contact with one surface of the second electrode plate; And And an auxiliary insulator attached to an interface between the first and second separators and the first and second electrode plates to insulate the first and second electrode plates. The method of claim 2, The auxiliary insulator is an electrode assembly, characterized in that the heat distortion temperature is 150 ℃ or more. The method of claim 3, wherein The auxiliary insulator is installed on the first and second electrode plates, the electrode assembly, characterized in that installed on the surface in contact with the first separator in the first electrode plate and the second electrode plate. The method of claim 4, wherein And the auxiliary insulator is installed on only one of the first and second electrode plates. The method of claim 5, And the auxiliary insulator is installed only on the uncoated portion of the first and second electrode plates. The method of claim 3, wherein And the auxiliary insulator is provided on a surface of the first and second separators in contact with the first electrode plate and the second electrode plate. The method of claim 3, wherein The auxiliary insulator is in the form of a paste, the electrode assembly, characterized in that applied to the separator or the first, second electrode plate. The method of claim 3, wherein The auxiliary insulator is an electrode assembly, characterized in that the tape having an adhesive on at least one side. The method of claim 3, wherein The auxiliary insulator is an electrode assembly, characterized in that formed of a material capable of transmitting the electrolyte. The method of claim 10, The tape is an electrode assembly, characterized in that formed of a polyolefin-based material except polyethylene. The method of claim 11, The tape is an electrode assembly, characterized in that formed of any one of polyimide (PI), polypropylene (PP), polyethylene terephthalate (PET). delete An electrode assembly including first and second separators interposed between the first and second electrode plates and the first and second electrode plates, and an auxiliary insulator included at an interface between the first and second electrode plates and the separator; A case accommodating the electrode assembly; And And a cap assembly sealing and closing the case. The method of claim 14, The secondary insulator is a secondary battery, characterized in that the heat deformation temperature is 150 ℃ or more. The method of claim 14, The case is a secondary battery characterized in that the cylindrical. The method of claim 14, The case is a secondary battery characterized in that the square. The method of claim 14, The case is a secondary battery, characterized in that the pouch type. The method of claim 14, The first electrode plate has a negative electrode polarity, characterized in that the. The method of claim 14, The auxiliary insulator is installed on the first electrode plate and the second electrode plate, and the first and second electrode plates are installed on the surface corresponding to the separator in contact with both surfaces of the first and second electrode plates. Secondary battery. The method of claim 14, The auxiliary insulator is installed on the first and second separators, and the secondary battery is installed on at least one surface of the both surfaces of the first and second separators in contact with the first electrode plate and the second electrode plate.

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