BUTTON-TYPE SECONDARY BATTERY

A button-type secondary battery includes an electrode assembly having a first electrode with a first electrode tab and a second electrode with a second electrode tab; a can accommodating the electrode assembly and to which the first electrode tab is connected; a top cap coupled to an opening of the can and to which the second electrode tab is connected; and a first insulation member insulating the first electrode tab. The first electrode tab includes a first coupling surface coupled to the first electrode and a second coupling surface extending from the first coupling surface and coupled to the can. The first insulation member includes a first insulator attached to an outer circumferential surface of the electrode assembly to cover the first coupling surface, and a second insulator horizontally extending from an upper end of the first insulator toward a top surface of the electrode assembly.

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims the benefit of the priority of Korean Patent Application Nos. 10-2020-0120949, filed on Sep. 18, 2020, 10-2021-0020704, filed on Feb. 16, 2021, and 10-2021-0123771, filed on Sep. 16, 2021, which are hereby incorporated by reference in their entirety.

TECHNICAL FIELD

The present invention relates to a button-type secondary battery that increases in insulation of an electrode tab to prevent short circuit from occurring.

BACKGROUND ART

In general, secondary batteries refer to chargeable and dischargeable, unlike primary batteries that are not chargeable. The secondary batteries are being widely used for mobile phones, notebook computers, and camcorders, electric vehicles, and the like.

The secondary battery comprises a button-type secondary battery having a high energy density, a high output, and a long lifespan. The button-type secondary battery comprises an electrode assembly, a can having an accommodation groove accommodating the electrode assembly, a top cap coupled to the can to finish the accommodation groove, and a gasket sealing a gap between the can and the top cap.

Also, the electrode assembly has a structure in which a first electrode and a second electrode are sequentially stacked with a separator therebetween. Here, the first electrode is provided with a first electrode tab connected to the can, and the second electrode is provided with a second electrode tab connected to the top cap.

An insulating tape having insulation is attached to the first electrode tab and the second electrode tab coupled to the electrode assembly.

However, the insulating tape according to the related art has a problem in that, when the electrode assembly is pressed and deformed, the first electrode tab or the second electrode tab is exposed outside the insulating tape, resulting in short circuit.

DISCLOSURE OF THE INVENTION

Technical Problem

The present invention is invented to solve the above problems, and an object of the present invention is to provide a button-type secondary battery, in which an insulation member that insulates an electrode tab coupled to an electrode assembly is supplemented to prevent the electrode tab from being exposed outside the insulation member even though the electrode assembly is deformed, to prevent short circuit from occurring, thereby improving safety.

Technical Solution

A button-type secondary battery according to the present invention for achieving the above object comprises: an electrode assembly comprising a first electrode provided with a first electrode tab and a second electrode provided with a second electrode tab; a can which accommodates the electrode assembly and to which the first electrode tab is connected; a top cap which is coupled to an opening of the can and to which the second electrode tab is connected; and a first insulation part provided with a first-a insulation member configured to insulate the first electrode tab connected to the first electrode, wherein the first electrode tab comprises a first-a coupling surface coupled to the first electrode of the electrode assembly and a first-b coupling surface extending from the first-a coupling surface between a bottom surface of the electrode assembly and a bottom surface of the can and coupled to the can, and the first-a insulation member comprises a first-a insulator attached to an outer circumferential surface of the electrode assembly to cover the first-a coupling surface, wherein both ends of the first-a insulation member are attached to extend up to upper and lower ends of the outer circumferential surface of the electrode assembly and a first-b insulator horizontally extending from an upper end of the first-a insulator toward a top surface of the electrode assembly.

The first insulation part may further comprise a first-b insulation member attached to the bottom surface of the can to cover the first-b coupling surface.

Corresponding ends of the first-a insulation member and the first-b insulation member may be disposed in a state of partially overlapping each other to insulate a portion of the first electrode tab disposed between the first-a insulation member and the first-b insulation member.

The first-b insulation member may be provided to be attached to the entire bottom surface of the can.

An insulation plate configured to insulate the electrode assembly and the top cap from each other may be provided between the electrode assembly and the top cap.

An end of the first-b insulator extending to the top surface of the electrode assembly may be attached to a top surface of the insulation plate.

The second electrode tab may comprise a second-a coupling surface coupled to the second electrode of the electrode assembly and a second-b coupling surface extending from the second-a coupling surface between the top surface of the electrode assembly and the top cap and coupled to the top cap, wherein the button-type secondary battery may comprise a second insulation part attached to the outer circumferential surface of the electrode assembly to cover the second-a coupling surface.

The second insulation part may comprise a second-a insulator attached to the outer circumferential surface of the electrode assembly, wherein both ends of the second-a insulator may be attached to extend up to the upper and lower ends of the outer circumferential surface of the electrode assembly, and a second-b insulator extending from a lower end of the second-a insulator to the bottom surface of the electrode assembly.

The second insulation part may comprise a second-c insulator horizontally extending from an upper end of the second-a insulator to the top surface of the electrode assembly.

An insulation plate may be provided between the electrode assembly and the top cap, and an end of the second-c insulator may be attached to the insulation plate.

The can may comprise a bottom surface, on which the electrode assembly is disposed, and a wall surface formed along an edge of the bottom surface to form an electrode assembly accommodation space, the top cap may comprise a cover surface configured to finish an accommodation space of the can and a coupling surface formed along an edge of the cover surface and coupled to the wall surface, and a gasket configured to seal a gap between the can and the top cap and insulate the can and the top cap from each other may be provided between the can and the top cap.

The can may comprise a bottom surface, on which the electrode assembly is disposed, and a wall surface formed along an edge of the bottom surface to form an electrode assembly accommodation space, the top cap may comprise a top plate which is coupled to the opening of the can and in which an insertion hole is formed, and an electrode terminal inserted into the insertion hole and connected to the second electrode tab, and a gasket configured to seal a gap between the top plate and the electrode terminal and insulate the top plate and the electrode terminal from each other may be provided between the top plate and the electrode terminal.

An outer circumferential side of the top plate and an inner circumferential side of an upper end of the can may be welded to be coupled so that the top plate and the can are coupled to be sealed.

The welding may comprise seam welding.

Advantageous Effects

The button-type secondary battery according to the present invention may comprise the electrode assembly, the can, the top cap, the gasket, the first electrode tab provided with the first-a coupling surface and the first-b coupling surface, and the first insulation part provided with the first-a insulation member, wherein the first-a insulation member may comprise the first-a insulator and the first-b insulator.

That is, the first-a insulator may be attached to the outer circumferential surface of the electrode assembly so that the first-a coupling surface is covered. Here, both the ends may be attached to extend to the upper end and the lower end of the outer circumferential surface of the electrode assembly, and the first-b insulator may extend horizontally from the upper end of the first-a insulator toward the top surface of the electrode assembly. Therefore, even if the deformation occurs in the electrode assembly, the first electrode tab may be prevented from being exposed outside the first-a insulation member to prevent the short circuit from occurring, thereby improving the safety.

MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings in such a manner that the technical idea of the present invention may easily be carried out by a person with ordinary skill in the art to which the invention pertains. The present invention may, however, be embodied in different forms and should not be construed as limited to the embodiments set forth herein. In the drawings, anything unnecessary for describing the present invention will be omitted for clarity, and also like reference numerals in the drawings denote like elements.

[Button-type secondary battery according to first embodiment of the present invention]

As illustrated inFIGS.1to3, a button-type secondary battery100according to a first embodiment of the present invention comprises an electrode assembly110comprising a first electrode111provided with a first electrode tab150and a second electrode112provided with a second electrode tab160, a can120accommodating the electrode assembly110, a top cap130coupled to an opening of the can120, a gasket140insulating the can120from the top cap130, a first electrode tab150connecting a first electrode of the electrode assembly110to the can120, a second electrode tab160connecting a second electrode of the electrode assembly110to the top cap130, a first insulation part170insulating the first electrode tab coupled to the first electrode, a second insulation part180insulating the second electrode tab coupled to the second electrode, and an insulation plate190insulating the electrode assembly110and the top cap130from each other.

Electrode Assembly

The electrode assembly110has a structure in which the first electrode and the second electrode are alternately stacked with a separator therebetween and which is wound in a jelly-roll shape. Here, a distal end of the first electrode111and a distal end of the second electrode112are disposed on the outermost sides of the electrode assembly110, respectively. In addition, the first electrode tab150is connected to a distal end of the first electrode111, and the second electrode tab160is connected to a distal end of the second electrode112.

The first electrode111is a negative electrode, and the second electrode is a positive electrode. Of course, the first electrode tab is a negative electrode tab, and the second electrode tab is a positive electrode tab.

The can120has a structure that forms an accommodation space accommodating the electrode assembly and comprises a bottom surface121, on which the electrode assembly110is disposed, and a wall surface122formed along an edge of the bottom surface121to form an electrode assembly accommodation space.

Top Cap

The top cap130is coupled to an opening of the can to finish the accommodation space of the can and comprises a cover surface131disposed on the opening of the can120to finish the accommodation space of the can120and a coupling surface132formed along an edge of the cover surface131and coupled to the wall surface122.

That is, the can and the top cap are coupled to each other in a compression manner.

Gasket

The gasket140is provided at a coupled portion of the can and the top cap to seal a gap between the can and the top cap and comprises an outer gasket141provided between the wall surface122of the can120and the coupling surface132of the top cap130, an inner gasket142that is in close contact with the inside of the wall surface122, and a connection gasket143connecting the outer gasket141to the inner gasket142.

First Electrode Tab

The first electrode tab150is configured to connect the first electrode of the electrode assembly to the can and comprises a first-a coupling surface151coupled to a distal end of the first electrode111disposed at the outermost side of the electrode assembly110and a first-b coupling surface152extending from the first-a coupling surface151between a bottom surface of the electrode assembly110and the bottom surface121of the can120and coupled to the bottom surface121of the can120.

Second Electrode Tab

The second electrode tab160is configured to connect the second electrode of the electrode assembly to the top cap and comprises a second-a coupling surface161coupled to a distal end of the first electrode112disposed at the outermost side of the electrode assembly110and a second-b coupling surface162extending from the second-a coupling surface161between a top surface of the electrode assembly110and the cover surface131of the top cap130and coupled to the cover surface131of the top cap130.

First Insulation Part

The first insulation part170is configured to insulate the first electrode tab and insulates the first electrode tab170connecting the first electrode111disposed at the outermost side of the electrode assembly110to the can120.

Second Insulation Part

The second insulation part180is configured to insulate the second electrode tab and insulates the second electrode tab160connecting the second electrode112disposed at the outermost side of the electrode assembly110to the top cap130.

Insulation Plate

The insulation plate190is configured to insulate the electrode assembly from the top cap, is made of a material having insulation, and is provided between a top surface of the electrode assembly110and the cover surface131of the top cap130to insulate the electrode and the top cap130from each other.

The button-type secondary battery has a structure in which it is difficult to sufficiently secure upper and lower spaces of the electrode assembly because a diameter thereof is greater than a height thereof. In the button-type secondary battery having such a structure, when pressed in a height direction by an external impact or pressure, the electrode assembly110is deformed into a flat shape, and thus, the first electrode tab150coupled to the outermost side of the electrode assembly110may be exposed to the outside of the first insulation part170, and the second electrode160may be exposed to the outside of the second insulation part180. That is, the first electrode tab150may be exposed to the outside through a bonded portion of the first insulation part170and the electrode assembly110, and the second electrode tab160may be exposed to the outside through a bonded portion of the second insulation part180and the electrode assembly110. Thus, the button-type secondary battery has a risk of internal short circuit when pressed to be deformed. (It means a problem that occurs when the first insulation part and the second insulation part are formed differently from the form according to the present invention described below).

In order to solve this problem, the button-type secondary battery100according to the first embodiment of the present invention supplements the structures of the first insulation part170and the second insulation part180to prevent the first and second electrode tabs150and160from being exposed to the outside of the first and second insulation parts170and180even though the electrode assembly110is pressed to be deformed, thereby removing the risk of the short circuit inside the button-type secondary battery.

That is, the first insulation part170comprises a first-a insulation member171insulating the first-a coupling surface151of the first electrode tab150coupled to the first electrode111disposed at the outermost side of the electrode assembly110. The first-a insulation member171may be attached to an outer circumferential surface of the electrode assembly110to completely cover the first-a coupling surface151to effectively insulate the entire first-a coupling surface151and also prevent the first-a coupling surface151from being exposed to the outside of the first-a insulation member171even though the electrode assembly110is deformed.

Here, the first-a insulation member171comprises a first-a insulator171aattached to extend so that both ends correspond to upper and lower ends of an outer circumferential surface of the electrode assembly110when viewed inFIG.1and a first-b horizontally extending from an upper end of the first-a insulator171atoward the top surface of the electrode assembly110, which is perpendicular to the first-a insulator171a. Thus, the first-a insulation member171disposed on upper and lower ends of the first electrode tab150may increase in area, and thus, even though the electrode assembly is pressed to be flat, the first electrode tab150may be prevented from being exposed to the outside through the upper and lower ends of the first-a insulation member.

Particularly, a gap between the upper end of the first-a insulator171aand the upper end of the electrode assembly110may be finished through the first-b insulator171b. That is, referring toFIG.2, the first-a insulator171aand the first-b insulator171bmay be bent in a state of being connected to each other to finish the bonded portion between the upper end of the electrode assembly110and the upper end of the first-a insulator171a, thereby preventing the first electrode tab150from being significantly exposed to the outside between the upper end of the first-a insulation member171and the upper end of the electrode assembly110.

The first insulation part170further comprises a first-b insulation member172that insulates the first-b coupling surface152. The first-b insulation member172is attached to the bottom surface121of the can120so that the first-b coupling surface152is completely covered. Particularly, the first-b insulation member172is attached to the bottom surface121in a state in which a left end extends to a boundary point between the first-a coupling surface151and the first-b coupling surface152when viewed inFIG.1. Thus, even when deformation occurs in a radial and longitudinal direction of the electrode assembly110, it is possible to prevent the first-b coupling surface152from being significantly exposed to the outside of the first-b insulation member172.

The end of the first-b insulator171bextending to the top surface of the electrode assembly110is attached to a top surface of the insulation plate190. Thus, it is possible to increase in adhesive force of the first-b insulator171b, and as the first-b insulator171bholds one end of the insulation plate190, an increase in fixing force and a moving phenomenon of the insulation plate190may be greatly prevented.

The first-a insulator, the first-b insulator, and the first-c insulator are integrally formed, and the first insulation member and the first-d insulator are integrally formed.

The second insulation part180comprises a second-a insulator181, which is attached to the outer circumferential surface of the electrode assembly110so that the second-a coupling surface161is covered and has both ends attached to extend so as to match the upper and lower ends of the outer circumferential surface of the electrode assembly110, and a second-b insulator182attached to extend from a lower end of the second-a insulator181to the bottom surface of the electrode assembly110. Thus, an area of the second insulation part180disposed on the upper and lower portions of the second-a coupling surface161coupled to the electrode assembly110may increase, and as a result, even though the electrode assembly110is deformed, the second electrode tab160may be significantly prevented from being exposed to the outside. Particularly, the gap between the lower end of the second-a insulator181and the lower end of the electrode assembly may be effectively finished through the second-b insulator182, and as a result, the second electrode tab160may be significantly prevented to the outside between the second-a insulator181and the electrode assembly.

The second insulation part180may comprise a second-c insulator183horizontally extending from an upper end of the second-a insulator181to the top surface of the electrode assembly110, and thus, the second-c insulator183may effectively finish a gap between the upper end of the second-a insulator181and the upper end of the electrode assembly to significantly prevent the second electrode tab160from being exposed to the outside between the second-a insulator181and the electrode assembly.

An end of the second-c insulator183extending to the top surface of the electrode assembly110may be attached to the insulation plate190to increase in adhesive force of the end of the second-c insulator183. Thus, the second-c insulator183may hold the other end of the insulation plate190to significantly prevent the increase in fixing force and the moving phenomenon of the insulation plate190.

The corresponding ends of the first-a insulation member171and the first-b insulation member172(a lower end of the first-a insulation member and a right end of the first-b insulation member when viewed inFIG.1) are disposed to partially overlap each other, thereby effectively insulating a portion (i.e., a boundary line connecting the first-a coupling surface to the first-b coupling surface) of the first electrode tab150disposed between the first-a insulation member171and the first-b insulation member172. That is, referring toFIG.3, the first-a insulation member171and the first-b insulation member172may surround the boundary line x between the first-a coupling surface151and the first-b coupling surface152to significantly prevent the boundary point between the first-a insulation member171and the first-b insulation member172from being exposed to the outside.

For example, the first-a insulation member171comprises a first-c insulator171chorizontally extending from the lower end of the first-a insulator to the bottom surface of the first-b coupling surface152and attached to the first-b insulation member172. Also, the first-b insulation member172comprises a first-d insulator172avertically extending from a left end to the first-a coupling surface151when viewed inFIG.1and attached to the first-a insulation member171. Thus, the first-c insulator171cand the first-d insulator172amay be provided to stably insulate and protect the first-a coupling surface151and the first-b coupling surface152.

Therefore, the button-type secondary battery100according to the first embodiment of the present invention may comprise the first insulation part170and the second insulation part180to significantly prevent the first and second electrode tabs from being exposed to the outside even though the electrode assembly is deformed and also significantly prevent the internal short circuit from occurring, thereby improving the safety.

Hereinafter, in descriptions of another embodiment of the present invention, constituents having the same configuration and function as the above-mentioned embodiment have been given the same reference numeral in the drawings, and thus duplicated description will be omitted.

Button-Type Secondary Battery According to Second Embodiment of the Present Invention

As illustrated inFIG.5, a button-type secondary battery100according to a second embodiment of the present invention comprises a first-b insulation member172attached to a first-b coupling surface152of a first electrode tab150.

Here, the first-b insulation member172is attached to a bottom surface121in a state in which a right end of the first-b insulation member172extends up to a boundary point between a bottom surface121and a wall surface122. Thus, even though the electrode assembly110is deformed in a radial and longitudinal direction of the electrode assembly, the first-b coupling surface152may be significantly prevented from being exposed to the outside of the first-b insulation member172. That is, costs may be reduced by minimizing consumption of the first-b insulation member172, and the electrode assembly110and the can120may be effectively insulated.

Button-Type Secondary Battery According to Third Embodiment of the Present Invention

As illustrated inFIG.5, a button-type secondary battery100according to a third embodiment of the present invention comprises a first-b insulation member172attached to a first-b coupling surface152of a first electrode tab150.

Here, the first-b insulation member172is attached to an entire bottom surface121of the can120. Thus, it is possible to effectively insulate the electrode assembly110from the can120without installing a separate insulation plate between the can120and the electrode assembly, thereby improving safety.

Button-Type Secondary Battery According to Fourth Embodiment of the Present Invention

As illustrated inFIGS.6and7, a button-type secondary battery100according to a fourth embodiment of the present invention comprises an electrode assembly110comprising an electrode assembly110comprising a first electrode111provided with a first electrode tab150and a second electrode112provided with a second electrode tab160, a can120accommodating the electrode assembly110and connected to the first electrode tab150, a top cap130coupled to an opening of the can120and connected to the second electrode tab160, a first insulation part170insulating the first electrode tab150connected to the first electrode111, a second insulation part180insulating a second electrode tab160connected to the second electrode112, and an insulation plate190insulating the electrode assembly from the top cap130.

The electrode assembly, the first electrode tab, the second electrode tab, the first insulation part, the second insulation part, and the insulation plate have the same configuration and function as the electrode assembly, the can, the first electrode tab, the second electrode tab, the first insulation part, the second insulation part, and the insulation plate, and thus, their duplicated description will be omitted.

The can120comprises a bottom surface121, on which the electrode assembly110is disposed, and a wall surface122formed along an edge of the bottom surface121to form an accommodation space accommodating the electrode assembly110.

The top cap130comprises a top plate133coupled to an opening of the can120and having an insertion hole133aand an electrode terminal135inserted into the insertion hole133aand connected to the second electrode tab160.

A gasket140sealing a gap between the top plate133and the electrode terminal135and insulating the top plate133from the electrode terminal135is provided between the top plate133and the electrode terminal135.

The electrode terminal135is connected to the second electrode tab of the electrode assembly and comprises a connection part135ainserted into the insertion hole131aof the top plate133and coupled to the second electrode tab160through welding and a support part135bsupported on a top surface of the tap plate133.

The gasket140is configured to insulate the electrode terminal and the top plate and seal a gap between the electrode terminal and the top plate. That is, the gasket140comprises a vertical gasket141disposed in the insertion hole131abetween an inner circumferential side of the top plate133and an outer circumferential side of the electrode terminal135and a horizontal gasket142disposed between a top surface of the top plate133and a bottom surface of the electrode terminal135.

Here, the gasket140may be made of a material having insulation and sealing properties.

An adhesive means153bonding the gasket140to the top plate133or the electrode terminal135may be further provided.

As a first example, the adhesive means153may apply an adhesive having adhesive force to the gasket140so that the gasket140and the top plate133or the gasket140and the electrode terminal135adhere to each other.

As a second example, when heat is applied to the top plate, a portion of the gasket is melted to thermally fuse the gasket140and the top plate133or the gasket140and the electrode terminal135.

The outer circumferential side of the top plate133and the inner circumferential side of the upper end of the can120are welded so that the top plate133and the can120are coupled to be sealed. That is, the can120and the top cap130are coupled to each other in a welding manner.

Particularly, the welding of the top plate133and the can120may be seam welding. Preferably, the welding may be laser seam welding. The seam welding may be continuously performed through spot welding. That is, the seam welding is a method for performing the welding by rotating the electrode while using the electrode having a rotating roller shape and supplying welding current. Such the seam welding is used for a continuous operation for a container and a long pipe that require sealing. Particularly, when the roller for the seam welding is rotated, large supply current is required because a portion of the supply current flows to the welded portion first, and a portion of the supply current flows between roller electrodes. As described above, the can and the top plate may be welded through the seam welding so that the can and the top plate is coupled to be sealed.

The top plate133is seated on a seating protrusion123formed on an inner wall of the can120to improve coupling between the top plate133and the can120.

Therefore, in the button-type secondary battery100according to the fourth embodiment of the present invention, the top plate133and the can120may be coupled to each other in the welding manner to increase in coupling force between the top plate133and the can120, and thus, the accommodation space of the can120may be stably seated.

Accordingly, the scope of the present invention is defined by the appended claims more than the foregoing description and the exemplary embodiments described therein. Various modifications made within the meaning of an equivalent of the claims of the invention and within the claims are to be regarded to be in the scope of the present invention.

Description of the Symbols