KR100760786B1 - Secondary battery and the same using method - Google Patents

Abstract

The secondary battery has a cap plate formed with a case having an opening at one side, an electrode assembly accommodated in the case and having the first and second electrode tabs withdrawn therethrough, and an electrolyte injection hole for covering the opening of the case and injecting electrolyte at one side. And a cap assembly having a cap plate, a protective circuit board connected to the cap assembly and a cap plate connected to the cap assembly to connect the cap assembly and the protective circuit board, and having a protrusion formed at a lower side thereof to cover an electrolyte injection hole. Since the process of forming a stopper for sealing the injection hole and the process of combining the same, the process efficiency is increased and the production cost is reduced.

Secondary battery, electrolyte solution, electrolyte injection hole

Description

Secondary battery and manufacturing method using same {SECONDARY BATTERY AND THE SAME USING METHOD}

1 is an exploded perspective view of a secondary battery according to the present invention;

Figure 2a, 2b is a perspective view showing a lead plate of a secondary battery according to the present invention,

3A is a partial cross-sectional view of a rechargeable battery according to the present invention;

3B is a partial cutaway view of a secondary battery according to the present invention;

4A, 4B, and 4C are assembly flowcharts of a secondary battery according to the present invention;

5 is a flowchart illustrating a method of manufacturing a secondary battery according to the present invention.

<Brief Description of Major Codes in Drawings>

100 cap assembly 110 cap plate

111: first terminal through hole 112: electrolyte injection hole

120: gasket 130: first electrode terminal

140: insulation plate 141: second terminal through

150: terminal plate 151: third terminal through

160: insulation case 200: case

210: first electrode 215: first electrode tab

220: second electrode 225: second electrode tab

230: separator 250: electrode assembly

300: protection circuit board 310,320: first and second external terminals

410,420: first and second lead plate 411: depression

413 spin

The present invention relates to a secondary battery, and more particularly, to a secondary battery provided with a cap plate and a lead plate.

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.

Secondary batteries have been recently developed and used because they are rechargeable and have a small and large capacity. Typical secondary batteries include nickel 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 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, a bare cell of a lithium secondary battery is formed by receiving an electrode assembly composed of a first and second electrode plates and a separator coated with an active material in a secondary battery case and injecting an electrolyte solution to seal the cap assembly.

Since the case is formed of aluminum or an aluminum alloy, the light properties of the aluminum can make the battery lighter, and there is an advantage such that it does not corrode even when used for a long time under high voltage.

The bare cells of these secondary batteries are typically provided with electrode terminals insulated from the peripheral portions on top thereof, and the electrode terminals are connected to one electrode of the electrode assembly in the bare cell to form a positive terminal or a negative terminal of the battery. The can itself has a polarity opposite to that of the electrode terminal.

The bare cell electrode terminal of the sealed secondary battery is electrically connected to terminals of safety devices such as a positive temperature coefficent (PTC) and a protective circuit module (PCM). Safety devices are connected to the first and second electrodes to cut off the current when the voltage of the battery rises rapidly due to the high temperature of the battery or excessive charge / discharge.

In this case, it is not easy in terms of the shape and material of the bare cell to directly connect and electrically connect the electrodes of the bare cell to electrical terminals such as a protective circuit board. Thus, a conductor structure called a lead plate serves to connect the electrical terminals of safety devices such as the positive and negative electrodes of the battery and the protective circuit board. As a material of the lead plate, nickel or a nickel alloy is usually used, but stainless steel plated with nickel is used. The safety device and the bare cell may be stored in a separate pack in an electrically connected state, or filled with a space between the molten resins and coated to form a completed battery pack.

Here, in the cap assembly, the cap plate is the main body, and the electrode terminal is installed in the central hole of the cap plate through an insulating gasket. An electrolyte injection hole may be formed at one side of the cap plate around the electrode terminal, and a safety valve may be installed at the other side. The electrolyte inlet is formed to inject the electrolyte into the case after the case is closed with the cap assembly. After injection of the electrolyte, the electrolyte injection hole is press-fitted with an aluminum plug, and laser welding is performed between the stopper and the cap plate to prevent leakage of the electrolyte solution through a minute gap between the electrolyte injection hole and the stopper. In addition, the upper side of the stopper may be added a UV coating process to prevent the leakage of the electrolyte by forming a sealing material by applying a liquid resin or dropping the resin droplet (코) to harden it with light or heat.

At this time, the lead plate is formed to have a short length so as not to cover the top surface of the plug so that the UV coating process can be performed on the top surface of the plug.

However, a lead plate made of nickel may cause a problem in welding with a case made of aluminum. In other words, nickel and aluminum are not easy for ultrasonic welding or resistance welding due to the insolubility of nickel and the excellent conductivity of aluminum.

Therefore, if the welding of the lead plate, the cap plate, and the case is not performed properly, the finished secondary battery causes a failure in mechanical strength or a poor electrical connection.

In order to solve the problems as described above, an object of the present invention is to provide a secondary battery having a lead plate to reduce the coupling process of the cap plate and the lead plate.

The present invention for achieving the above object is a case having one side is opened, an electrode assembly accommodated in the inside of the case and the first and second electrode tabs are drawn out, covers the opening of the case and injects electrolyte to one side A cap assembly having a cap plate having an electrolyte injection hole formed therein, a protective circuit board connected to the cap assembly, and installed on an upper surface of the cap plate to connect the cap assembly and the protective circuit board and cover the electrolyte injection hole at a lower side thereof. A secondary lead plate including a first lead plate having a protrusion formed thereon and a second lead plate coupled to an upper surface of the cap plate and connecting a first electrode terminal installed in an insulated state to the cap plate and the protective circuit board; Provide a battery.

The projection of the first lead plate may be fitted into the electrolyte injection hole.

An upper surface of the first lead plate may have a depression recessed inward at a position corresponding to the protrusion of the first lead plate.

The depression may be larger than the electrolyte injection hole.

The depression may be spaced apart from the electrolyte injection hole and may be formed in a ring shape.

Preferably, the recess is welded to couple the cap plate and the first lead plate, and the welding may be laser welding.

The case may be rectangular.

In addition, the present invention comprises the steps of accommodating the electrode assembly with the first and second electrode tabs drawn out in the case, installing a cap assembly including a cap plate formed with an electrolyte injection hole to cover the opening of the case, the electrolyte solution on the lower side Installing a first lead plate having protrusions inserted into an injection hole, installing a second lead plate, fixing the first lead plate and the cap plate, and fixing the first lead plate and the cap assembly to the second lead plate and the cap assembly. A method of manufacturing a secondary battery, the method comprising: fixing a first electrode terminal installed in an insulated state, and connecting the first and second lead plates and the protection circuit board, respectively.

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

1 is an exploded perspective view of a secondary battery according to the present invention, Figures 2a, 2b is a perspective view showing an electrode lead plate of a secondary battery according to the present invention.

3A is a partial cross-sectional view of a secondary battery according to the present invention, FIG. 3B is a partial cutaway view of the secondary battery according to the present invention, and FIGS. 4A, 4B and 4C are assembly flowcharts of the secondary battery according to the present invention.

Referring to these drawings, the secondary battery is coupled to the case 200 having an opening at one side, an electrode assembly 250 accommodated in the case 200, and an opening 201 of the case 200, and the case 200. It has a bare cell consisting of a cap assembly 100 for sealing the top of the.

In the present embodiment, the case 200 is formed of aluminum or an aluminum alloy having a substantially rectangular box shape to accommodate the electrode assembly 250 and the electrolyte through the opening 201 of the case 200. The case 200 may itself serve as an electrode terminal of any one of the first and second electrodes 215 and 225.

The electrode assembly 250 is formed in a thin plate shape or a film shape, and the second electrode 220 to which the first electrode 210, the separator 230, and the second electrode tab 225 to which the first electrode tab 215 is attached are attached. ) Is formed by winding in a spiral shape. In this case, the first and second electrodes 210 and 220 may be a cathode or an anode. Here, it is preferable that the first electrode 210 is typically a cathode.

The negative electrode, which is the first electrode, includes a negative electrode current collector made of a conductive metal sheet, such as a copper foil, and a negative electrode active material layer mainly composed of a carbon material coated on both surfaces thereof. The first electrode tab 215 serving as a negative electrode lead is connected to a region of the negative electrode current collector in which the negative electrode active material layer is not formed, and is led out to the negative electrode of the first electrode 210.

The positive electrode, which is the second electrode, includes a positive electrode current collector made of a thin metal plate such as aluminum foil having excellent conductivity, and a positive electrode active material layer coated on both surfaces thereof and having a lithium oxide as a main component. In the positive electrode, which is the second electrode 220, the second electrode tab 225, which functions as a positive electrode lead, is electrically connected to a region of the positive electrode current collector in which the positive electrode active material layer is not formed and is drawn out.

The separator 230 is made of polyethylene, polypropylene, or a copolymer of polyethylene and polypropylene (Co-Polymer), and is formed wider than the first and second electrodes 210 and 220 to short-circuit between the electrode plates. It is advantageous to prevent.

The cap assembly 100 is a case 200 covers and seals the opening 201, and is provided with a flat cap plate 110 having a size and a shape corresponding to the opening 201 of the case 200. . An insulating plate 140 is installed on the lower surface of the cap plate 110, and a terminal plate 150 electrically connected to the first electrode tab 215 provided on the first electrode 210 on the lower surface of the insulating plate 140. Is installed.

The cap plate 110 has a first terminal through-hole 111 connected to the first electrode tab 215 through the first electrode terminal 130 at a central portion thereof, and a first electrode in the first terminal through-hole 111. A tubular gasket 120 is installed to electrically insulate the terminal 130 and the cap plate 110.

Here, the gasket 120 is preferably formed in the same height as the height of the first electrode terminal 130 to cover the outer surface of the first electrode terminal 130.

In addition, an electrolyte injection hole 112 of a predetermined size is formed at one side of the cap plate 110. The electrolyte injection hole 112 is a protrusion of the first lead plate 410 when the cap assembly 100 is assembled to the upper opening 201 of the case 200, and then electrolyte is injected through the electrolyte injection hole 112. 413).

The insulating plate 140 is formed of an insulating material such as the gasket 120 and is coupled to the bottom surface of the cap plate 110. The insulating plate 140 is formed to correspond to and communicate with the first terminal through-hole 111 of the cap plate 110 is a second terminal through-hole 141 is formed.

The terminal plate 150 is formed of Ni metal or an alloy thereof, and is coupled to the lower surface of the insulating plate 140. The terminal plate 150 has a third terminal through hole 151 corresponding to the first terminal through hole 111 of the cap plate 110.

In addition, the insulating case 160 is installed on the upper side of the electrode assembly 250 to insulate the electrode assembly 250 and the cap plate 110, is a polymer resin having an insulating property, preferably made of polypropylene, In the embodiment of the present invention, the material is not limited. Insulating case 160 has electrode tab through holes 163 and 165 and electrolyte through holes 161.

Then, the periphery of the cap plate 110 and the upper end of the side wall of the case 200 are welded.

Meanwhile, the first electrode terminal 130 serving as the cathode and the cap plate 110 serving as the anode are electrically connected to the protection circuit board 300 through the first and second lead plates 410 and 420.

The protection circuit board 300 is provided with a circuit portion and connection terminals 360 and 370 on the rear surface, that is, the inner surface on which the external terminals 310 and 320 are formed. The connection terminals 360 and 370 may be coupled to the first and second lead plates 410 and 420.

Here, the first and second lead plates 410 and 420 may be made of nickel or a nickel alloy material as usual, and the first lead plate 410 may be combined with the cap plate 110 as shown in FIG. 2A. The bottom portion is formed in a substantially rectangular shape, and the periphery of the bottom portion has a wall portion that protrudes perpendicularly to the cap plate 110 surface at least in part.

In addition, a lower surface of the first lead plate 410, as shown in Figure 2b, a projection 413 protruding downward to be inserted into the electrolyte injection hole 112 formed in the cap plate 110 is formed, the upper surface A ring 411 is formed around the protrusion 413 and is recessed into the cap. At this time, the depression 411 is formed larger than the electrolyte injection hole 112.

That is, the coupling of the first lead plate 410 and the cap plate 110 is a projection 413 formed on the lower side of the first lead plate 410 in the electrolyte injection hole 112 formed in the cap plate 110 is suppressed. And by welding the recessed portion 411 recessed inwardly to form a welded portion 415.

Hereinafter, a method of manufacturing a secondary battery according to the above configuration will be described in detail.

First, as shown in FIGS. 4A, 4B, 4C, and 5, the electrode assembly 250 is accommodated in the case 200.

Next, the case 200 is sealed with the cap assembly 100. In this case, the first and second electrode tabs 215 and 225 of the electrode assembly 250 are connected to the first electrode terminal 130 and the cap plate 110 of the cap assembly 100, respectively (S510).

Next, the electrolyte is injected into the case 200 through the electrolyte injection hole 112 of the cap plate 110.

First and second lead plates 410 and 420 are installed on the upper surface of the case 200 into which the electrolyte is injected. Here, the first lead plate 410 is connected to the cap plate 110 and the protrusion 413 formed below the first lead plate 410 is forcibly fitted into the electrolyte injection hole 112 to inject the electrolyte injection hole 112. Seal it (S530).

Next, a ring-shaped depression 413 formed in the first lead plate 410 is laser-welded to bond the cap plate 110 and the first lead plate 410 to seal the electrolyte injection hole 112. (S550)

In the secondary battery according to the present invention, since the electrolyte injection hole is not provided with a separate stopper and is sealed by a protrusion formed in the lead plate, a process of forming a stopper and a process of combining the stopper are reduced, thereby increasing process efficiency and reducing production cost. It is effective.

In addition, the secondary battery has an effect of strengthening the sealing of the electrolyte injection hole by welding the cap plate and the lead plate, which are periphery of the electrolyte injection hole, through the depression formed in the lead plate.

Claims (13)

A case in which one side is opened; An electrode assembly accommodated in the case and having first and second electrode tabs drawn out therethrough; A cap assembly covering an opening of the case and having a cap plate having an electrolyte injection hole for injecting an electrolyte solution on one side thereof; A protective circuit board connected to the cap assembly; A first lead plate installed on an upper surface of the cap plate to connect the cap assembly to the protective circuit board, and having a protrusion formed at a lower side thereof to cover the electrolyte injection hole; And And a second lead plate coupled to an upper surface of the cap plate in an insulated state and connecting the first electrode terminal and the protection circuit board to be insulated from the cap plate. The method of claim 1, The protrusion of the first lead plate is forcibly fitted into the electrolyte injection hole. The method of claim 2, The secondary battery of claim 1, wherein an upper surface of the first lead plate has a depression recessed inward at a position corresponding to the protrusion of the first lead plate. The method of claim 3, wherein The depression part is a secondary battery, characterized in that formed larger than the electrolyte injection hole. The method of claim 4, wherein The recessed part is formed to be spaced apart from the electrolyte injection hole and the secondary battery, characterized in that formed in a ring shape. The method of claim 5, The recessed part is characterized in that the secondary battery is welded to join the cap plate and the first lead plate. The method of claim 6, The welding is a secondary battery, characterized in that the laser welding. The method of claim 1, The case is a secondary battery characterized in that the square. Accommodating the electrode assembly with the first and second electrode tabs drawn out into the case; Installing a cap assembly including a cap plate having an electrolyte injection hole formed to cover the opening of the case; Installing a first lead plate having protrusions inserted into the electrolyte injection hole at a lower side thereof; Installing a second lead plate; Fixing the first lead plate and the cap plate; Fixing a first electrode terminal installed insulated from the second lead plate and the cap assembly; And And connecting the first and second lead plates and the protection circuit board, respectively. The method of claim 9, The protrusion is a manufacturing method of a secondary battery, characterized in that the insertion into the electrolyte injection hole. The method of claim 10, The first lead plate is a manufacturing method of a secondary battery, characterized in that the depression is formed in a ring shape at a predetermined interval with the electrolyte injection hole is recessed inward. The method of claim 11, And the first lead plate and the cap plate are fixed by welding the recesses of the first lead plate. The method of claim 12, The welding is a method of manufacturing a secondary battery, characterized in that the laser welding.

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