KR101264425B1 - Cap assembly and rechargeable battery using the same - Google Patents

Abstract

The present invention relates to a cap assembly and a secondary battery using the same. More specifically, a sealing means is formed at an electrode terminal penetrating the gasket, so that a corresponding portion of the gasket is formed by a suction force generated during pin spinning compression. By expanding and filling the sealing means, the sealing efficiency of the electrode terminal and the gasket is improved, and leakage of the electrolyte is prevented.

Electrode terminal, sealing means, depression step part, gasket, protrusion step part, leakage prevention

Description

CAP ASSEMBLY AND RECHARGEABLE BATTERY USING THE SAME}

1 is a longitudinal cross-sectional view of a cap assembly according to an embodiment of the present invention.

Figure 2a is a perspective view of the electrode terminal according to an embodiment of the present invention.

Figure 2b is an embodiment of a depression stepped in the electrode terminal according to an embodiment of the present invention.

Figure 2c is another embodiment of the depression stepped in the electrode terminal according to an embodiment of the present invention.

Figure 3a is a coupling diagram of the electrode terminal and the gasket according to an embodiment of the present invention.

Figure 3b is another coupling of the electrode terminal and the gasket according to an embodiment of the present invention.

4 is a longitudinal cross-sectional view of a rechargeable battery according to an exemplary embodiment of the present invention.

<Description of the symbols for the main parts of the drawings>

10: Cap plate 11: Terminal hole

12: Electrolyte amount inlet 13: Stopper

14: safety band 20: electrode terminal

30: Head 40: Body part

41: sealing means, depression step 50: gasket

60: stepped part 70: protrusion stepped part

80: Insulation plate 90: Terminal plate

100: cap assembly 200: electrode assembly

210: positive electrode plate 220: negative electrode plate

230: separator 240: positive electrode tap

250: negative electrode tab 300: case, can

400: insulation case 410: lead through

420: electrolyte passage hole

The present invention relates to a cap assembly and a secondary battery using the same, and more particularly, to a cap assembly and a secondary battery using the same to prevent leakage of the electrolyte by forming a sealing means on the electrode terminal.

In general, secondary batteries, unlike disposable batteries, are batteries that can be repeatedly used when they are charged. They are mainly used as power sources for wireless communication, information processing, and audio / video multi-devices.

The main reason for the recent focus on secondary batteries and rapid development is that secondary batteries are ultra-light power sources with high energy density, high output voltage and low self discharge rate, as well as environmentally friendly and long lifespan.

Secondary batteries are divided into Ni-Cd, Ni-MH, and lithium secondary batteries according to electrode active materials. In particular, lithium secondary batteries are mainly composed of a lithium oxide as a cathode active material and a cathode active material. Carbon material is used.

In addition, lithium secondary batteries are classified into liquid electrolyte batteries and polymer electrolyte batteries according to the type of electrolyte. 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.

In addition, lithium secondary batteries are manufactured in various shapes, and typical shapes are cylindrical, rectangular, and pouch types.

Lithium-ion batteries have a much higher energy density per weight than disposable batteries, making it possible to realize ultra-light batteries. The average voltage per cell is 3.6V, which is three times the compact effect of 1.2V of other rechargeable batteries such as Ni-Cd batteries or nickel-metal hydride batteries. There is.

In addition, the lithium ion battery has a self-discharge rate of less than 5% per month at 20 ° C, which is about one third of that of a nickel-cadmium battery or nickel-metal hydride battery, and is environmentally friendly by not using heavy metals such as cadmium (Cd) or mercury (Hg). In addition, there is an advantage that can be charged and discharged 1000 times or more in a normal state. Therefore, on the basis of these advantages, with the recent development of information and communication technology, the development is rapidly made.

Typically, the lithium ion 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 to prevent lithium ion (Li-ion). An electrode assembly in which a separator capable of moving only is wound, a can containing the electrode assembly, an electrolyte injected into the can to enable movement of lithium ions, a cap assembly for sealing an upper opening of the can, etc. Consists of

Such lithium ion batteries are generally manufactured as follows.

First, a cathode electrode plate coated with the cathode active material and a cathode tab connected with a cathode active material, a cathode electrode plate coated with a cathode active material, an anode tab connected with a separator, and a separator are stacked, and then wound to prepare an electrode assembly.

Then, the electrode assembly is accommodated in the can to prevent the electrode assembly from being separated, and then the cap assembly is coupled with the can. Thereafter, the electrolyte is injected into the can and then sealed to complete the lithium secondary battery.

The cap assembly includes a cap plate having a terminal through hole, an electrode terminal penetrating through the terminal through hole, and a gasket interposed between the cap plate and the terminal through hole. The electrode terminal wraps an outer circumference with a gasket. In the state is coupled to the terminal hole of the cap plate.

Conventionally, as a method of sealing the electrode terminal to the gasket, a vertical pinning (Pin Spinning) compression method of the vertical compression method is used, as a result of the use of the Pin Spinning compression method, the electrode terminal and the gasket Since the minute gap is formed between the sealing degree is weak. Therefore, there is a problem in that the electrolyte inside the leakage to the fine gap. In addition, as the amount of the electrolyte is increased inside the battery for high capacity, the conventional coupling structure of the upper gasket and the electrode terminal has a problem in that the electrolyte leaks easily to the outside due to a short gap due to the electrolyte leakage path.

Therefore, a change in the structure of the electrode terminal to maximize the sealing efficiency of the gasket and the electrode terminal, and a change in the coupling structure of the upper gasket and the electrode terminal to block the leakage of the electrolyte to the outside is required.

Accordingly, the present invention has been made to solve the above-described problems, and to provide a cap assembly and a secondary battery using the same by applying a structural change to the electrode terminal penetrating the terminal through hole to improve the sealing efficiency of the electrode terminal and the gasket. The purpose.

Another object of the present invention is to prevent the leakage of the electrolyte to the outside by changing the coupling structure of the upper portion of the gasket and the corresponding electrode terminal to prevent the formation of microgap.

In order to achieve the above object, the cap assembly according to the present invention includes a cap plate having a terminal through hole and an electrode terminal penetrating through the terminal through hole, and a gasket interposed between the electrode terminal and the cap plate to seal the terminal through hole. In the cap assembly is configured, the electrode terminal is seated on the upper portion of the gasket and the terminal through-hole and the inside of the gasket and the body portion formed with at least one sealing means formed in the outer peripheral portion It is done.

In addition, the sealing means may be formed in a circular shape along the outer circumference of the body portion of the electrode terminal.

In addition, the sealing means may be formed as a depression step.

In this case, the depression stepped portion may be made of a 'c' shape, or may be made of a '⊂' shape.

In addition, the gasket may have a protruding step portion filling the sealing means in the inner circumference of the position corresponding to the sealing means.

In this case, the protruding step portion may have a complementary shape corresponding to the recessed step portion.

In addition, the gasket may have two steps in the thickness direction, and the head portion of the electrode terminal may have a structure corresponding to the steps of the two steps.

In addition, an electrode assembly in which a positive electrode plate and a negative electrode plate and a separator interposed between the positive electrode plate and the negative electrode plate are stacked and wound, and the case in which the electrode assembly and the electrolyte are accommodated therein; And a cap assembly including a cap plate having a terminal through-hole, an electrode terminal penetrating through the terminal through-hole, and a cap gasket interposed between the electrode terminal and the cap plate to seal the terminal through-hole. An electrode terminal is mounted on an upper portion of the gasket to seal a terminal through-hole; And a body portion penetrating the inside of the gasket and having at least one sealing means formed on an outer circumference thereof.

In addition, the sealing means may be formed as a depression step portion formed in a circular shape around the outer circumference of the electrode terminal. In this case, the depression stepped portion may be made of a 'c' shape, or may be made of a '⊂' shape.

In addition, the gasket may have a protrusion stepped portion filling the sealing means in the inner circumference of the position corresponding to the sealing means, the protrusion stepped portion may be formed in a complementary shape corresponding to the recessed step.

The gasket may have two steps at the top in the thickness direction, and the head of the electrode terminal may have a structure corresponding to the two steps.

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

A preferred embodiment of the cap assembly according to the present invention, as shown in Figure 1, the cap plate 10 for sealing the can (not shown) formed with the top opening, and the electrode terminal penetrating the cap plate (10) 20), a gasket 50 interposed between the cap plate 10 and the electrode terminal 20, an insulating plate 80 disposed on the bottom surface of the cap plate 10, and a lower surface of the insulating plate 80. It is configured to include a terminal plate 90 installed in.

The cap plate 10 has a terminal through-hole 11 at the center and an electrolyte injection hole 12 at one side thereof, and is formed in a flat shape having a size and a shape corresponding to the top opening of the can (not shown).

As shown in FIG. 2A, the electrode terminal 20 includes a head part 30 and a body part 40 penetrating the inside of the gasket 50. In addition, the bottom portion of the electrode terminal 20 is electrically connected to the terminal plate 90.

The body portion 40 of the electrode terminal 20 has a sealing means 41 is formed in the outer peripheral portion to increase the sealing degree of the electrode terminal 20 and the gasket 50. In this case, the sealing means 41 is preferably formed of at least one or more.

The sealing means 41 is formed in a circular shape along the outer circumference of the body portion 40 of the electrode terminal 20. In this embodiment, the sealing means 41 is made of a depression stepped portion 41 formed stepped in the thickness direction of the body portion 40 to increase the leakage path of the electrolyte.

At this time, the depression step portion 41 may be made of a 'c' shape, or '' 'shape as shown in Figure 2b and 2c. Since the recessed step portion 41 of the 'c' shape or the '자' shape has a concave space formed therein, the electrode terminal 20 is pin-pinned in the up and down direction in the gasket 50. During compression, the recessed step portion 41 and the portion of the corresponding gasket 50 are filled into the concave space by the suction force generated during the compression. Therefore, leakage of the electrolyte inside to the outside of the battery is primarily prevented and may be accumulated inside the battery.

The head portion 30 of the electrode terminal 20 is seated on the upper portion of the gasket 50 to seal the terminal through-hole (11).

The gasket 50 is formed in the shape of a tube of insulating material for electrical insulation between the electrode terminal 20 and the cap plate 10, and a stepped portion 60 is formed in the thickness direction thereon. At this time, the step portion 60 is formed in two stages, as shown in Figure 3a and 3b. Since the stepped portion 60 has a step formed in the thickness direction of the gasket 50 once more, the leakage path of the electrolyte may be further increased to prevent leakage of the electrolyte.

On the other hand, the head portion 30 of the electrode terminal 20 is formed in a structure corresponding to the stepped portion 60 of the second stage to be seated on the gasket 50 to seal the terminal through-hole (11).

In addition, as shown in FIG. 3B, the gasket 50 includes a protrusion step part filling the sealing means 41 during pin spinning compression on the inner circumference of the position corresponding to the sealing means 41. 70) is formed. At this time, the protruding step portion 70 is formed with at least one to correspond to the number of the sealing means (41).

In addition, the protruding stepped part 70 may be formed in a complementary shape so as to correspond to the recessed stepped part 41.

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

A preferred embodiment of the secondary battery according to the present invention, as shown in Figure 4, the electrode assembly 200, the case 300 is accommodated in the electrode assembly 200, and the upper opening of the case 300 The cap assembly 100 to seal is included.

The electrode assembly 200 is formed by winding or overlapping a laminate of the positive electrode plate 210 and the separator 230 and the negative electrode plate 220 formed in a thin plate or film form.

At least one surface of the positive electrode plate 210 and the negative electrode plate 220 is coated with a positive electrode active material or a negative electrode active material. Meanwhile, the positive electrode tab 240 is electrically connected to an area of the positive electrode current collector in which the positive electrode active material layer is not formed in the positive electrode plate 210, and in the area of the negative electrode current collector in which the negative electrode active material layer is not formed in the negative electrode plate 220. The negative electrode tab 250 is electrically connected. In this case, the positive electrode plate 210 and the negative electrode plate 220 and the electrical tabs 240 and 250 may be arranged with different polarities, and the tabs may be formed at the boundary portion from which the electrode tabs 240 and 250 are drawn out from the electrode assembly 200. Insulation tapes may be respectively wound to prevent short circuits between the two electrode plates.

In addition, the separator 230 may be formed to have a wider width than the positive electrode plate 210 and the negative electrode plate 220 to prevent short circuit between the electrode plates.

On the other hand, an insulating case 400 may be installed on the upper surface of the electrode assembly 200 to cover the electrical insulation of the electrode assembly 200 and the cap assembly 100 and to cover the upper end of the electrode assembly 100. , Insulation case 400 is made of a polymer resin having an insulating property. In addition, a lead through hole 410 is formed in the center portion of the insulating case 400 to allow the negative electrode tab 250 to pass therethrough, and an electrolyte passage hole 420 is formed at the other side.

In the present embodiment, the case 300 is made of a container of aluminum or aluminum alloy having a shape of the can 300, that is, the upper portion of the rectangular parallelepiped, and is formed by a processing method such as deep drawing.

The electrode assembly 200 is accommodated through the open top of the can 300 so that the can 300 serves as a container of the electrode assembly 200 and the electrolyte. The can 300 may itself serve as a terminal and is sealed by the cap assembly 100.

The cap assembly 100 includes a cap plate 10 for sealing an upper portion of the can 300, an electrode terminal 20 penetrating through the cap plate 10, the cap plate 10, and an electrode terminal ( Gasket 50 interposed between the 20, the insulating plate 80 is provided on the lower surface of the cap plate 10 and the terminal plate 90 is provided on the lower surface of the insulating plate 80 is configured.

The cap plate 10 is configured in a flat shape having a size and shape corresponding to the open top of the can 300. In this case, a terminal through hole 11 is formed in the central portion of the cap plate 10 so that the electrode terminal 20 penetrates. An electrolyte injection hole 12 for injecting an electrolyte into the can 300 is formed at one side of the cap plate 10. In addition, a stopper 13 is provided to seal the electrolyte inlet 12 after the electrolyte is injected. The stopper 13 is a ball-shaped base material formed of aluminum or an aluminum-containing metal, and is placed on the electrolyte inlet 12 and mechanically press-fitted into the electrolyte inlet 12. In addition, the plug 13 is welded to the cap plate 10 around the electrolyte inlet 12 for sealing.

In addition, the cap plate 10 has a safety vent 14 is formed so that the gas is released when the internal pressure rises on the other side to reach a predetermined pressure or more. The safety vent 14 is damaged when the pressure inside the battery rises above a predetermined pressure, thereby preventing ignition and explosion of the battery.

The electrode terminal 20 and the gasket 50 have the same configuration as the electrode terminal 20 and the gasket 50 of the preferred embodiment of the cap assembly 100 according to the present invention described above.

That is, the electrode terminal 20 penetrates the head 30 and the inside of the gasket 50 and seals the outer peripheral portion 41 to increase the degree of sealing of the electrode terminal 20 and the gasket 50. It is composed of at least one body portion 40 formed.

The sealing means 41 is formed of a circular recess stepped portion 41 on the outer circumference of the body portion 40 of the electrode terminal 20. At this time, the recess stepped portion 41 may be made of a 'c' shape, or may be made of a '⊂' shape.

The gasket 50 has two steps 60 formed thereon in the thickness direction. On the other hand, the head portion 30 of the electrode terminal 20 is formed in a structure corresponding to the stepped portion 60 of the second stage to be seated on the upper portion of the gasket 50 to seal the terminal through-hole (11).

In addition, the gasket 50 may be provided with a protruding step portion 70 filling the sealing means 41 in the inner circumference of the position corresponding to the sealing means 41. At this time, the protruding stepped portion 70 is formed in at least one or more to correspond to the number of the sealing means 41, the protruding stepped portion 70 is complementary to the corresponding recessed stepped portion 41 shape Is done.

On the other hand, the bottom portion of the electrode terminal 20 is electrically connected to the terminal plate 90. The positive electrode tab 240 drawn from the positive electrode plate 210 is welded to the lower surface of the cap plate 10, and the negative electrode tab 250 drawn from the negative electrode plate 220 is zigzag-shaped at the lower end of the electrode terminal 20. It is welded with a bend. In addition, the cap assembly 100 is coupled to the can 300 by welding the periphery of the cap plate 10 to the sidewall of the can 300 opening.

Next will be described the operation of the cap assembly according to the present invention configured as described above and the secondary battery using the same.

The body portion 40 of the electrode terminal 20 penetrating through the terminal hole 11 has at least one sealing means 41 is formed around the outer peripheral portion in a circular shape, the sealing means 41 is the body portion 40 It is made of a depression step portion 41 formed stepped in the thickness direction.

At this time, since the recess stepped portion 41 is formed in a 'c' shape or a '자' shape, a concave space is formed therein, and thus the electrode terminal 20 is moved up and down in the gasket 50 which is an insulator. In the case of pin spinning compression, the portion of the gasket 50 corresponding to the depression step 41 is expanded and filled by the suction force generated during the compression into the concave space. Therefore, the leakage path of the electrolyte is increased and the sealing degree of the electrode terminal 20 and the gasket 50 is improved, thereby preventing leakage of the internal electrolyte to the outside.

In addition, the gasket 50 has at least one protrusion step portion 70 having a complementary shape to correspond to the depression step portion 41 at an inner circumference of a position corresponding to the depression step portion 41. Can be. Therefore, during pin spinning compression, the protrusion step part 70 is filled in the depression step part 41, thereby improving the sealing degree of the electrode terminal 20 and the gasket 50.

On the other hand, the head portion 30 of the electrode terminal 20 has a stepped portion 60 is formed in two stages in the thickness direction, the upper portion of the gasket 50 also the head portion of the electrode terminal 20 in the thickness direction The stepped portion 60 of the second stage is formed to correspond to the 30, so that the head 30 of the electrode terminal 20 rests on the gasket 50 to seal the terminal through-hole 11. Since the stepped portion 60 is formed in the second step once more, the leakage path of the electrolyte is further increased and fine gaps are not formed, and thus leakage of the electrolyte to the outside by the capillary phenomenon is blocked.

The present invention is not limited to the technical spirit of the specific embodiments or drawings described above, and those skilled in the art without departing from the gist of the invention claimed in the claims Various modifications are possible, of course, and such changes are within the scope of the claims of the present invention.

As described above, the present invention provides a sealing efficiency of the electrode terminal and the gasket by filling the gasket correspondingly to the recessed step formed in the body of the electrode terminal by inflating itself by the suction force generated during pin spinning compression. It is effective to improve.

Another effect of the present invention is to prevent the leakage of the electrolyte to the outside by forming two stepped portions corresponding to each other on the head of the electrode terminal and the upper portion of the gasket to prevent the formation of microgap by the corresponding coupling.

Claims (16)

A cap assembly including a cap plate having a terminal through-hole, an electrode terminal passing through the terminal through-hole, and a gasket interposed between the electrode terminal and the cap plate to seal the terminal through-hole, The electrode terminal, A head part seated on an upper portion of the gasket to seal a terminal through-hole; And The body portion penetrates the inside of the gasket and has at least one sealing means formed on an outer circumference thereof. The gasket is formed with two steps in the thickness direction at the top, Cap assembly, characterized in that the head of the electrode terminal is formed in a structure corresponding to the step of the second stage. The method of claim 1, The sealing means, Cap assembly characterized in that it is formed in a circular shape along the outer periphery of the body portion of the electrode terminal. 3. The method of claim 2, The sealing means cap assembly, characterized in that formed by the depression step. The method of claim 3, Cap recess, characterized in that the depression step is made of '' 'shape. The method of claim 3, Cap recess, characterized in that the depression step portion is made of '⊂' shape. The method according to any one of claims 1 to 5, The gasket, Cap assembly characterized in that the protrusion stepped portion is formed in the inner peripheral circumference of the position corresponding to the sealing means is formed. The method according to claim 6, Cap assembly, characterized in that formed in at least one projecting step. 8. The method of claim 7, The protruding step portion cap assembly, characterized in that made in a complementary shape corresponding to the depression step portion. delete An electrode assembly in which a positive electrode plate, a negative electrode plate, and a separator interposed between the positive electrode plate and the negative electrode plate are stacked and wound; A case accommodating the electrode assembly and the electrolyte therein; And A secondary battery comprising a cap assembly including a cap plate having a terminal through-hole, an electrode terminal penetrating through the terminal through-hole, and a cap assembly interposed between the electrode terminal and the cap plate to seal the terminal through-hole. The electrode terminal, A head part seated on an upper portion of the gasket to seal a terminal through-hole; And The body portion penetrates the inside of the gasket and has at least one sealing means formed on an outer circumference thereof. The gasket is formed with two steps in the thickness direction at the top, The head of the electrode terminal is a secondary battery, characterized in that formed in a structure corresponding to the step of the two stages. The method of claim 10, The sealing means, Secondary battery, characterized in that formed in a circular shape around the outer periphery of the electrode terminal. 12. The method of claim 11, The sealing means is a secondary battery, characterized in that formed in the depression stepped portion. 13. The method of claim 12, The depression stepped portion is a secondary battery, characterized in that consisting of '' 'or' '' shape. The method according to any one of claims 10 to 13, The gasket, Secondary battery, characterized in that at least one protrusion stepped portion is formed in the inner peripheral circumference of the position corresponding to the sealing means. 15. The method of claim 14, And the protruding stepped portion has a complementary shape corresponding to the recessed stepped portion. delete

Images