EP-4738587-A1 - SECONDARY BATTERY AND BATTERY MODULE INCLUDING SAME

Abstract

The present invention relates to a secondary battery and a battery module including the same, and more particularly, to a secondary battery, in which venting for discharging an internal gas according to a typical design value at room temperature is performed, and faster venting than the existing venting is implemented at a high-temperature condition to quickly reduce internal heat generation and an internal gas pressure, thereby minimizing internal explosive power of the secondary battery, and a battery module including the same.

Inventors

• LEE, BYOUNG KOOK

Assignees

• LG Energy Solution, Ltd.

Dates

Publication Date

20260506

Application Date

20240821

Claims (11)

1. A secondary battery comprising: an electrode assembly; a can in which the electrode assembly is accommodated; and a cap assembly configured to cover an opening of the can, wherein the cap assembly comprises: a top cap provided with the outermost terminal for electrical connection to the outside; a safety vent disposed below the top cap and connected to the top cap at an outer portion thereof, wherein, when an internal pressure of the can rises above a critical value, a shape or position of a predetermined area inside the outer portion are changed; and a current interrupt device (CID) which is disposed below the safety vent and provided with an electrode tab connected to the electrode assembly on a bottom surface thereof, and of which a portion of a top surface is bonded to the safety vent on the predetermined area of the safety vent, wherein the safety vent comprises a venting notch having a recessed shape in a top or bottom surface thereof, and an additional material is attached to a surface of the venting notch, wherein the additional material has thermal conductivity greater than that of the safety vent.
2. The secondary battery of claim 1, wherein the venting notch is formed in the bottom surface of the safety vent.
3. The secondary battery of claim 1, wherein the venting notch has a V shape, and the additional material comprises a first portion attached to the surface of the venting notch.
4. The secondary battery of claim 3, wherein the first portion has a thickness less than that of the safety vent.
5. The secondary battery of claim 4, wherein the first portion is applied to the surface of the venting notch to cover an entire surface of the venting notch.
6. The secondary battery of claim 3, wherein the additional material further comprises a second portion attached to a surface of the safety vent, which is opposite to the surface in which the venting notch is formed, wherein the second portion is attached to a portion corresponding to a position at which the venting notch is disposed.
7. The secondary battery of claim 1, wherein the safety vent comprises an aluminum material, and the additional material comprises any one of silver and copper materials.
8. The secondary battery of claim 7, wherein the additional material is attached through either soldering or dipping.
9. The secondary battery of claim 1, wherein the safety vent comprises an aluminum material, and the additional material comprises any one of silicon carbide (SiC), beryllium oxide (BeO), aluminum nitride (AlN), aluminum oxide (Al 2 O 3 ), carbon, and polymer materials.
10. The secondary battery of claim 9, wherein the additional material is attached through either spraying or dipping.
11. A battery module comprising the plurality of secondary batteries of claim 1.

Description

TECHNICAL FIELD CROSS-REFERENCE TO RELATED APPLICATION The present application claims the benefit of the priority of Korean Patent Application No. 10-2023-0113892, filed on August 29, 2023, which is hereby incorporated by reference in its entirety. TECHNICAL FIELD The present invention relates to a secondary battery and a battery module including the same, and more particularly, to a secondary battery, in which venting for discharging an internal gas according to a typical design value at room temperature is performed, and faster venting than the existing venting is implemented at a high-temperature condition to quickly reduce internal heat generation and an internal gas pressure, thereby minimizing internal explosive power of the secondary battery, and a battery module including the same. BACKGROUND ART Secondary batteries are classified into cylindrical and prismatic batteries, in which an electrode assembly is built in a cylindrical or prismatic metal can, and pouch-type batteries, in which an electrode assembly is built in a pouch-type case made of an aluminum laminate sheet, depending on the shapes of the battery cases. In addition, the electrode assembly built into the battery case may be a power generation element that is chargeable and dischargeable and be classified into a jelly roll-type electrode assembly having a structure in which a separator is interposed between long sheet-shaped positive and negative electrodes coated with an active material and then is wound, a stacked type electrode assembly having a structure in which a plurality of positive and negative electrodes, each of which has a predetermined size, are sequentially stacked with a separator therebetween, and a stack and folding type electrode assembly having a structure in which bicells or full cells are wound by stacking positive and negative electrodes, each of which is provided into a predetermined radical unit, with a separator therebetween are wound. Among them, the jelly roll-type electrode assembly is widely manufactured because the jelly roll-type electrode assembly is easy to be manufactured and have an advantage of high energy density per weight. The jelly roll-type electrode assembly may be manufactured by assembling a stack, in which long sheet-shaped positive and negative electrodes with a separator therebetween are provided, and winding the stack in a longitudinal direction of the sheet in a state in which a core is in contact with one end of the electrode stack. In addition, the jelly roll-type electrode assembly may be inserted into a battery case provided as a metal can to form the cylindrical secondary battery. The cylindrical secondary battery is designed with high energy density, and due to the increasing energy density, the lithium secondary battery requires a high level of stability, and thus, the demand for the cylindrical battery is also increasing. FIG. 1 is a cross-sectional view illustrating a cap assembly in a secondary battery according to the related art. Referring to FIG. 1, a secondary battery 1 according to the related art includes an electrode assembly (not shown), a can (not shown) that accommodates the electrode assembly, and a cap assembly 2 that covers an upper opening of the can. FIG. 1 is illustrates a specific configuration of the cap assembly 2. The electrode assembly and the can are omitted from the illustration for convenience of explanation. In FIG. 1, the cap assembly 2 may include a top cap 11, a safety vent 12, and a current interrupt device 13. The top cap 11 may be configured to form the outermost terminal for electrical connection with the outside. The safety vent 12 may be disposed at a lower side of the top cap 11 and be connected to the top cap 11 from an outer portion. In the outer portion, the safety vent 12 may be seated on a main gasket 14. The safety vent 12 may be configured so that a central area 15, which is an inner area of the outer portion, is changed in shape when an internal pressure of the can increases. Particularly, the central area 15 may move upward to be deformed into a shape, in which the shape of the safety vent is inverted. In addition, the current interrupt device 13 may be disposed at the lower side of the safety vent 12, an electrode tab connected to the electrode assembly may be connected to a bottom surface, and the safety vent 12 may be connected to the central area 15. An auxiliary gasket 16 may be disposed on the outer portion of the current interrupt device to prevent contact between the safety vent 12 and the current interrupt device 13 except for the central area 15. In the related art, the central area 15 of the safety vent 12 and the central area of the current interrupt device 13 are welded to each other. In addition, a notch 13-a may be defined around the central area 15 that is the welded portion. The notch 13-a may be a portion that is broken when the internal pressure of the can rises above a critical point. When the notch 13-a is broken, a