US-12620654-B2 - Button-type secondary battery

US12620654B2US 12620654 B2US12620654 B2US 12620654B2US-12620654-B2

Abstract

A button-type secondary battery includes an electrode assembly; a lower can into which the electrode assembly is disposed; and an upper can configured to cover an opening of an upper end of the lower can. A beading part recessed inward is provided in an upper portion of the lower can. An end of the upper can has a bent shape so the upper can and the lower can are coupled to each other while an end point of the end of the upper can is inserted into the beading part.

Inventors

Min Gyu Kim
Yong Gon LEE
Je Jun Lee
Jae Won Lim
Geon Woo MIN
Min Su Cho
Joo Hwan SUNG
Sang Hak CHAE

Assignees

LG ENERGY SOLUTION, LTD.

Dates

Publication Date: 20260505
Application Date: 20210916
Priority Date: 20200916

Claims (12)

1 . A button-type secondary battery, comprising: an electrode assembly; a lower can into which the electrode assembly is disposed; and an upper can configured to cover an opening of an upper end of the lower can, wherein a beading part recessed inward is provided in an upper portion of the lower can, wherein an end of the upper can has a bent shape so the upper can and the lower can are coupled to each other while an end point of the end of the upper can is inserted into the beading part, wherein a collection space in which an internal gas is collected is between the upper can and the electrode assembly, wherein the upper can comprises: an upper can electrode terminal part connected to an electrode of the electrode assembly is configured to form a terminal, the upper can electrode terminal part being configured to cover the opening of the upper end of the lower can; a first bent part bent to extend in a vertical direction from an end of the upper can electrode terminal part toward a bottom surface of the lower can; and a second bent part bent to extend from an end of the first bent part in a horizontal direction toward a central axis of the lower can, the second bent part being disposed inside the beading part in a plan view, and wherein the lower can comprises a lower can upper end vertical part bent to extend upward in the vertical direction from an end of the beading part toward the upper can electrode terminal part.
2 . The button-type secondary battery of claim 1 , wherein the lower can upper end vertical part and the first bent part extend in the vertical direction parallel to each other and are disposed to face each other.
3 . The button-type secondary battery of claim 2 , further comprising an insulator configured to prevent the upper can and the lower can from being in contact with each other.
4 . The button-type secondary battery of claim 3 , wherein the insulator includes a polybutylene terephthalate (PBT) material.
5 . The button-type secondary battery of claim 3 , wherein the insulator comprises: a first insulator portion filled in a space surrounded by a top surface of the beading part, the lower can upper end vertical part, and the upper can electrode terminal part; a second insulator portion extending from the first insulator portion and filled in a space formed between the first bent part and the lower can upper end vertical part; and a third insulator portion extending from the second insulator portion and filled in a space formed between the second bent part and the beading part.
6 . The button-type secondary battery of claim 1 , wherein a center hole is formed in a center of the electrode assembly, and a center pin is at the center hole so as to be fully filled in the center hole.
7 . The button-type secondary battery of claim 1 , further comprising an electrode tab configured to connect an electrode of the electrode assembly to the upper can electrode terminal part, wherein the electrode tab has one end connected to the electrode of the electrode assembly, and the electrode tab has the other end connected to a bottom surface of the upper can electrode terminal part in a C-shape.
8 . The button-type secondary battery of claim 5 , wherein the upper can further comprises an upper can protrusion protruding from at least one of the upper can electrode terminal part, the first bent part, or the second bent part toward the insulator.
9 . The button-type secondary battery of claim 5 , wherein the lower can further comprises a lower can protrusion protruding from at least one of the beading part or the lower can upper end vertical part toward the insulator.
10 . The button-type secondary battery of claim 1 , wherein a methyl orange PH sheet is attached to an outer wall of the lower can.
11 . The button-type secondary battery of claim 1 , wherein a diameter of the button-type secondary battery is greater than a height of the button-type secondary battery.
12 . The button-type secondary battery of claim 1 , wherein beading portion is horizontally adjacent to the collection space, and the beading portion is higher than the electrode assembly with respect to the vertical direction.

Description

CROSS-REFERENCE TO RELATED APPLICATION The present application claims the benefit of the priority of Korean Patent Application Nos. 10-2020-0119500, filed on Sep. 16, 2020, and 10-2021-0109102, filed on Aug. 18, 2021, which are hereby incorporated by reference in their entirety. TECHNICAL FIELD The present invention relates to a button-type secondary battery, and more particularly, to a button-type secondary battery, which is capable of collecting a gas within the battery even if an excessive internal pressure is generated by the gas generated in the battery to prevent the battery from being disassembled or prevent a gas that is harmful to the human body from leaking to the outside of the battery by the gas pressure and prevent an electrolyte from leaking to the outside of the battery. BACKGROUND ART In recent years, the price of energy sources increases due to the depletion of fossil fuels, the interest in environmental pollution is amplified, and the demand for eco-friendly alternative energy sources is becoming an indispensable factor for future life. Accordingly, studies on various power generation technologies such as solar power, wind power, and tidal power are continuing, and power storage devices such as batteries for more efficiently using the generated electrical energy are also of great interest. Furthermore, as technology development and demand for electronic mobile and electric vehicles using batteries increase, the demands for batteries as energy sources are rapidly increasing. Thus, many studies on batteries which are capable of meeting various demands have been conducted. In particular, in terms of materials, there is a high demand for lithium secondary batteries such as lithium ion batteries and lithium ion polymer batteries having advantages such as high energy density, discharge voltage, and output stability. The secondary batteries are classified into cylindrical batteries and prismatic batteries, in which an electrode assembly is embedded in a cylindrical or prismatic metal can, and pouch-type batteries, in which an electrode assembly is embedded in a pouch-type case made of an aluminum laminate sheet according to shapes of battery cases. Also, recently, due to the trend of smaller wearable devices, the importance of developing small batteries such as button-type secondary batteries has been highlighted. FIG. 1 is a cross-sectional view of a button-type secondary battery according to the related art. Referring to FIG. 1, a button-shaped secondary battery 10 according to the related art has a shape that is divided into upper and lower housings and has a structure in which an upper cylindrical can 4 and a lower cylindrical can 3 are press-fitted. That is, an outer diameter of the lower cylindrical can 3 is slightly larger than that of an upper portion thereof to realize the press-fitting. In the case of the press-fitting, it is the principle that a shape of the button-type secondary battery is maintained due to friction force due to the press-fitting. Also, in the button-shaped secondary battery according to the related art, the upper can 4 and the lower can 3 are manufactured to match a size of an internal electrode assembly 1 so as to be press-fitted with each other, and thus, there is no available space therein. However, in this configuration, when the internal pressure increases due to generation of an internal gas, etc., there is no fixing force other than frictional force, and thus, there is a high possibility that the upper can 4 and the lower can 3 are separated from each other. If the internal pressure rises, the internal pressure may rise due to side reactions and also rise during a normal cycle, but if the internal pressure excessively rises, the upper can and the lower can are separated from each other and thus may not function as a battery. Therefore, a battery capable of collecting a gas caused by the internal reaction of the battery is required, and studies on a product in which the upper can is not separated from each other is also required. In addition, the button-type secondary battery 10 according to the related art had a structure with a high possibility of leakage of the electrolyte. That is, since a leak path through which the electrolyte leaks is simple, possibility of leakage of the electrolyte is high, and thus, many studies have been conducted to solve this problem. DISCLOSURE OF THE INVENTION Technical Problem The present invention has been devised to solve the above problems, and an object of the present invention is to collect a gas within the battery even if an excessive internal pressure is generated by the gas generated in the battery so as to prevent the battery from being disassembled or prevent a gas that is harmful to the human body from leaking to the outside of the battery by the gas pressure and prevent an electrolyte from leaking to the outside of the battery. Technical Solution A button-type secondary battery, of which a diameter is greater than a