KR20060027279A - Cylindrical li ion secondary battery - Google Patents

Abstract

The present invention relates to a cylindrical lithium ion secondary battery capable of improving battery capacity of a lithium ion secondary battery and simplifying a manufacturing process by using an electrode cap integrated with a positive temperature element in a cap assembly. A wound electrode assembly having a 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; An upper metal film including a protruding portion and a flat portion having a central portion projecting upward, a positive temperature device material layer contacting a lower surface of the upper metal film flat portion, and a lower metal film contacting a lower surface of the positive temperature device material layer; A cylindrical lithium ion secondary battery including an electrode cap, the cap assembly coupled to an upper part of the case to seal the cap, and having a terminal part electrically connected to any one of the first electrode and the second electrode of the electrode assembly. It is characterized by providing.

Lithium Ion Secondary Battery, Cap Assembly, Electrode Cap, Positive Temperature Element

Description

Cylindrical Li-Ion Secondary Battery

1A is a perspective view illustrating a cylindrical lithium ion secondary battery according to an embodiment of the present invention.

1B is a cross sectional view along line 1a-1a in FIG.

2A and 2B are views for explaining a cylindrical lithium ion secondary battery according to an embodiment of the present invention.

(Explanation of symbols for main parts of drawing)

100; Cylindrical lithium ion secondary battery 200; Electrode assembly

210; First electrode plate 215; First electrode tab

220; Second electrode plate 225; Second electrode tab

230; Separators 241 and 245; Insulation Plate

300; Lithium Ion Secondary Battery Case

310; Side plates 320; Bottom plate

330; Creeping section 340; Beading part

400; Cap assembly 410; Safety band

420; Printed circuit board 430; Electrode cap

430a; Upper metal film 430b; Positive temperature element material layer

430c; Lower metal film 440; Insulation Gasket

500; Electrolyte

The present invention relates to a lithium ion secondary battery, and more particularly, in a cap assembly, by using an electrode cap integrated with a positive temperature element, battery capacity of a lithium ion secondary battery can be improved and a manufacturing process can be simplified. A cylindrical lithium ion secondary battery.

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.

In general, the cylindrical 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 between the positive electrode plate and the negative electrode plate to prevent a short and prevent lithium ions (Li-ion). An electrode assembly having a separator capable of moving only, a cylindrical case for a lithium secondary battery accommodating the electrode assembly, a cap assembly coupled to and sealed at an upper portion of the cylindrical case, and injected into the lithium secondary battery case It consists of electrolyte solution etc. which allow the movement of lithium ion.

The cylindrical lithium secondary battery is coated with the positive electrode active material and the positive electrode tab is connected to the positive electrode tab, the negative electrode active material is coated, the negative electrode tab is connected to the negative electrode plate and the separator is laminated, and then wound to prepare an electrode assembly.

Thereafter, the electrode assembly is accommodated in the cylindrical case for the lithium secondary battery, and a predetermined region of the upper cylindrical case of the electrode assembly is beaded so as not to detach. Then, after the electrolyte is injected into the lithium secondary battery case, by assembling and crimping the cap assembly on the upper portion of the cylindrical case, the cap assembly is mechanically strongly coupled and fixed to the cylindrical case to the cylindrical lithium secondary Complete the battery.

On the other hand, the cap assembly generally comprises an insulating gasket formed in a ring shape on the outer surface, a safety vent positioned inside the insulating gasket, a printed circuit board, a positive temperature element, and an anode cap.

However, the cap assembly as described above has a relatively large distance from the electrode assembly to the positive electrode cap due to the beading and creeping process, and thus, the height of the electrode plate is smaller than the height of the entire can, thus limiting battery capacity. There is.

In addition, by including a plurality of parts in the cap assembly, the assembly process of the cap plate has a complicated problem.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above problems of the prior art, and the present invention improves the battery capacity of a lithium ion secondary battery by using an electrode cap integrated with a positive temperature element in a cap cook body. The object is to provide a cylindrical lithium ion secondary battery that can simplify the process.

The present invention for achieving the above object is 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; An upper metal film including a protruding portion and a flat portion having a central portion projecting upward, a positive temperature device material layer contacting a lower surface of the upper metal film flat portion, and a lower metal film contacting a lower surface of the positive temperature device material layer; A cylindrical lithium ion secondary battery including an electrode cap, the cap assembly coupled to an upper part of the case to seal the cap, and having a terminal part electrically connected to any one of the first electrode and the second electrode of the electrode assembly. It is characterized by providing.

The positive temperature element material layer and the lower metal film may be formed in a ring shape.

The upper metal film and the lower metal film may be made of a conductive metal. Preferably, the upper metal film and the lower metal film are made of Ni.

The positive temperature element material layer may be formed in a form in which carbon is dispersed in a polymer resin, and the polymer resin is preferably Styrene Butadiene Rubber (SBR) resin.

In addition, the present invention provides a wound electrode assembly including 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; An electrode cap including an upper metal film, a lower metal film, and a positive temperature element material layer interposed between the upper metal film and the lower metal film, the electrode cap being coupled to and sealed to an upper portion of the case, A cylindrical lithium ion secondary battery comprising a cap assembly with a terminal portion electrically connected to any one of the first electrode plate and the second electrode plate is provided.

In addition, the present invention provides a wound electrode assembly including 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 having an electrode cap integrated with a positive temperature element, the cap assembly having a terminal portion coupled to an upper part of the case to seal the cap and electrically connected to any one of the first electrode plate and the second electrode plate of the electrode assembly; It is characterized by providing a cylindrical lithium ion secondary battery comprising.

The electrode cap may include an upper metal layer having a central portion protruding upward and including a protrusion and a flat portion; A positive temperature element material layer in contact with the bottom surface of the upper metal film flat portion; It may have a structure having a lower metal film in contact with the lower surface of the positive temperature element material layer.

Alternatively, the electrode cap may have a structure in which a center portion protrudes upward and includes a protrusion and a flat portion, and includes a positive temperature element material layer interposed between an upper metal layer, a lower metal layer, and the upper metal layer and the lower metal layer. have.

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

1A is a perspective view illustrating a cylindrical secondary battery according to an embodiment of the present invention, and FIG. 1B is a cross-sectional view taken along the line 1a-1a of FIG. 1A.

As illustrated in FIGS. 1A and 1B, the cylindrical lithium secondary battery 100 according to an exemplary embodiment of the present invention includes an electrode assembly 200 that generates a voltage difference during charging and discharging, and accommodates the electrode assembly 200. A cylindrical case 300, a cap assembly 400 assembled on the cylindrical case 300 to prevent the electrode assembly 200 from being separated, and injected into the cylindrical case 300 to the electrode assembly ( It consists of an electrolyte 500 to enable the movement of lithium ions between the 200.

The electrode assembly 200 may include any one of a positive electrode active material and a negative electrode active material, for example, a first electrode plate 210 coated with the positive electrode active material, another one of the positive electrode active material and the negative electrode active material, for example, a negative electrode active material. A short of the first electrode plate 210 and the second electrode plate 220 is disposed between the coated second electrode plate 220, the first electrode plate 210, and the second electrode plate 220. ) And a separator 230 that allows only lithium ions to move. In addition, the first electrode plate 210, the second electrode plate 220, and the separator 230 are wound in a substantially circular shape and accommodated in the cylindrical case 300. In addition, the first electrode plate 210 is generally made of aluminum (Al), protrudes a predetermined length upward, and is bonded to the first electrode tab 215, for example, an anode tab. The second electrode plate 220 is generally made of nickel (Ni), protrudes a predetermined length downward, for example, the second electrode tab 225, which is a negative electrode tab, is bonded, but in the present invention It does not limit the material. In addition, upper and lower insulating plates 241 and 245 are further attached to upper and lower portions of the electrode assembly 200 to avoid direct contact with the cap assembly 400 or the cylindrical case 300, respectively.

The cylindrical case 300 has a cylindrical side plate 310 having a predetermined diameter and a predetermined diameter so that the cylindrical electrode assembly 200 can be coupled, and the cylindrical side plate 310 is formed at the lower portion of the cylindrical side plate 310. A lower plate 320 blocking the lower space of the side plate 310 is formed, and an upper portion of the cylindrical side plate 310 is opened to insert the electrode assembly 200. Meanwhile, any one of the first and second electrode tabs 215 and the second electrode tab 225 of the electrode assembly 200 may be disposed at the center of the bottom plate 320 of the cylindrical case 300, for example, the second electrode tab ( As the 225 is electrically bonded, the cylindrical case 300 itself serves as a positive or negative terminal. In addition, the cylindrical case 300 is generally formed of aluminum (Al), iron (Fe) or an alloy thereof. In addition, the cylindrical case 300 has a crimping portion 330 that is bent to one side to press the cap assembly 400 at the top thereof, and is pressed inward to press the cap assembly 400 in the upper direction from the bottom thereof. A recessed beading portion 340 is further formed.

The cap assembly 400 is welded to another one of the first electrode tab 215 and the second electrode tab 225, for example, the first electrode tab 215 is welded, and the shape of the cap assembly 400 is reversed when overcharged or overheated. The conductive safety vent 410 and the electrically conductive safety vent 410 are electrically and mechanically connected to each other so that the circuit is broken when the safety vent 410 is inverted. And a conductive electrode cap 430 electrically connected to the upper portion of the printed circuit board 420 and applying an actual current to the outside, and the safety vent 410, the printed circuit board 420, and the electrode cap 430. It is formed of an insulating gasket 440 that surrounds the side circumference and insulates the ones listed above from the cylindrical case 300. In this case, the electrode cap 430 simultaneously serves as a positive temperature element. That is, the electrode cap 430 is formed in an integrated form with a positive temperature coefficient (PTC), and is electrically and mechanically connected to the upper portion of the printed circuit board 420 to allow a current to flow over a predetermined temperature. It serves to block.

The electrolyte 500 serves as a moving medium of lithium ions (Li Ion) generated by an electrochemical reaction at the positive and negative electrodes inside the battery during charging and discharging, which is a non-aqueous water mixture of lithium salts and high purity organic solvents. The organic electrolyte may be. In addition, the electrolyte 500 may be a polymer using a polymer electrolyte, and the type of the electrolyte material is not limited thereto.

2A and 2B are views for explaining a lithium ion secondary battery according to an exemplary embodiment of the present invention, and are shown as being limited to the electrode cap of the cap assembly.

Referring to FIG. 2A, the electrode cap 430 according to the embodiment of the present invention has an upper metal film 430a formed of a structure in which a central portion thereof protrudes upward and includes a protrusion 430d and a flat portion 430e. And a positive temperature element material layer 430b in contact with the lower surface of the upper metal film flat portion, and a ring-shaped lower metal film 430c in contact with the lower surface of the positive temperature element material layer 430b. .

In this case, since the positive temperature element material layer 430b and the lower metal film 430c are formed along the flat portion of the upper metal film 430a, the positive temperature device material layer 430b may have a ring-shaped structure.

In addition, referring to FIG. 2B, the electrode cap 430 of the lithium ion secondary battery cap assembly 400 according to the embodiment of the present invention may have an upper metal film 430a, a lower metal film 430c, and the upper metal. The film has a triple layer structure in which a positive temperature element material layer 430b is interposed between the film 430a and the lower metal film 430c, and a central portion protrudes upward to include a protrusion 430d and a flat portion 430e. Made of structure. Although not shown in the drawings, the electrode cap 430 may further include a through hole through which the gas inside may be discharged to the outside.

In this case, the upper metal film 430a and the lower metal film 430c are made of a conductive metal. Preferably, the upper metal film 430a and the lower metal film 430c are made of nickel (Ni). It does not limit the material in the present invention.

In addition, the positive temperature element material layer 430b is preferably formed in a form in which carbon is dispersed in a polymer resin, and as the polymer resin, it is preferable to use styrene butadiene rubber (SBR, Styrene Butadiene Rubber) resin. It does not limit the material in this invention.

As described above, the lithium ion secondary battery 100 according to the embodiment of the present invention omits the positive temperature element by adding the function of the positive temperature element to the electrode cap 440 of the cap assembly 400, and thus the cap. Assembly 400 may be formed. Thus, the assembly process of the cap assembly 400 can be simplified more.

In addition, by omitting the positive temperature element, the distance from the electrode assembly 400 to the electrode cap 430 is reduced, and thus, the electrode assembly among the heights of the case 300 for the entire lithium ion secondary battery. The height occupied by the first electrode plate 210 and the second electrode plate 220 of 200 may increase, thereby improving battery capacity of the lithium ion secondary battery 100.

 As described above, according to the present invention, in the cap cook body, by using an electrode cap integrated with the positive temperature element, the cylindrical lithium can improve the battery capacity of the lithium ion secondary battery and simplify the manufacturing process. An ion secondary battery can be provided.

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 (12)

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; An upper metal film including a protruding portion and a flat portion having a central portion projecting upward, a positive temperature device material layer contacting a lower surface of the upper metal film flat portion, and a lower metal film contacting a lower surface of the positive temperature device material layer; And a cap assembly having an electrode cap, wherein the cap assembly is coupled to an upper portion of the case to seal the cap and has a terminal portion electrically connected to any one of a first electrode and a second electrode of the electrode assembly. Ion secondary battery. The method of claim 1, And the positive temperature element material layer and the lower metal film are formed in a ring shape. The method of claim 1, The upper metal film and the lower metal film is a cylindrical lithium ion secondary battery, characterized in that made of a conductive metal. The method of claim 3, wherein The upper metal film and the lower metal film is a cylindrical lithium ion secondary battery, characterized in that made of Ni. The method of claim 1, The positive temperature element material layer is a cylindrical lithium ion secondary battery, characterized in that the carbon is dispersed in a polymer resin. The method of claim 5, The polymer resin is a cylindrical lithium ion secondary battery, characterized in that the styrene butadiene rubber (SBR, Styrene Butadiene Rubber) resin. 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; An electrode cap including an upper metal film, a lower metal film, and a positive temperature element material layer interposed between the upper metal film and the lower metal film, the electrode cap being coupled to and sealed to an upper portion of the case, A cylindrical lithium ion secondary battery comprising a cap assembly having a terminal portion electrically connected to one of the first electrode plate and the second electrode plate. The method of claim 7, wherein The upper metal film and the lower metal film is a cylindrical lithium ion secondary battery, characterized in that made of a conductive metal. The method of claim 7, wherein The positive temperature element material layer is a cylindrical lithium ion secondary battery, characterized in that the carbon is dispersed in a polymer resin. 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 having an electrode cap integrated with a positive temperature element, the cap assembly having a terminal portion coupled to an upper part of the case to seal the cap and electrically connected to any one of the first electrode plate and the second electrode plate of the electrode assembly; Cylindrical lithium ion secondary battery comprising a. The method of claim 10, The electrode cap may include an upper metal layer having a central portion protruding upward and including a protrusion and a flat portion; A positive temperature element material layer in contact with the bottom surface of the upper metal film flat portion; And a lower metal film in contact with the lower surface of the positive temperature element material layer. The method of claim 10, The electrode cap has a protruding portion and a flat portion with a central portion protruding upward, A cylindrical lithium ion secondary battery comprising an upper metal film, a lower metal film, and a positive temperature element material layer interposed between the upper metal film and the lower metal film.

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