US-12620673-B2 - Pouch-shaped battery cell including electrode lead capable of maintaining uniform internal pressure and battery pack including the same

US12620673B2US 12620673 B2US12620673 B2US 12620673B2US-12620673-B2

Abstract

The present invention relates to a pouch-shaped battery cell including a battery case made of a laminate sheet, an electrode assembly received in the battery case, the electrode assembly having an electrode tab protruding therefrom, an electrode lead electrically connected to the electrode tab, the electrode lead extending outwards from the battery case, and a gas discharge portion located in the electrode lead, wherein it is possible to prevent the internal pressure of the pouch-shaped battery cell from being increased to a predetermined level or more.

Inventors

Kee Bum KIM
Sei Woon Oh
Ye Jin NAM
Dong Hee Kim

Assignees

LG ENERGY SOLUTION, LTD.

Dates

Publication Date: 20260505
Application Date: 20211101
Priority Date: 20201102

Claims (10)

1 . A pouch-shaped battery cell comprising: a battery case made of a laminate sheet; an electrode assembly received in the battery case, the electrode assembly having an electrode tab protruding therefrom; an electrode lead electrically connected to the electrode tab, the electrode lead extending outwards from the battery case; and a gas discharge portion extending within the electrode lead, wherein the gas discharge portion is configured to block movement of gas when an internal pressure of the pouch-shaped battery cell is equal to or less than an external pressure at an outside of the pouch-shaped battery cell, and to discharge gas in the pouch-shaped battery cell when the internal pressure of the pouch-shaped battery cell is greater than the external pressure, and without a separate structure configured to close the gas discharge portion.
2 . The pouch-shaped battery cell according to claim 1 , wherein the gas discharge portion provides communication between an inside of the pouch-shaped battery cell and the outside of the pouch-shaped battery cell.
3 . The pouch-shaped battery cell according to claim 1 , wherein the gas discharge portion has an inlet located inside of a sealed portion of the battery case, and the gas discharge portion has an outlet located outside of the sealed portion of the battery case.
4 . The pouch-shaped battery cell according to claim 3 , wherein the gas discharge portion comprises a U-shaped pipe received within the electrode lead, and the inlet and the outlet are each located on a same side surface of the electrode lead.
5 . The pouch-shaped battery cell according to claim 4 , wherein the gas discharge portion comprises a first gas discharge passage and a second gas discharge passage, each of the gas discharge passages having a U-shaped pipe shape, the first gas discharge passage has a first inlet and a first outlet formed on a first side surface of the electrode lead, the first side surface extending parallel to an extension direction of the electrode lead, and the second gas discharge passage has a second inlet and a second outlet formed on a second side surface of the electrode lead, the second side surface being opposite from the first side surface and extending parallel to the extension direction of the electrode lead.
6 . The pouch-shaped battery cell according to claim 3 , wherein the gas discharge portion comprises an I-shaped pipe received within the electrode lead, the inlet of the gas discharge portion is located on a first side surface of the electrode lead, the first side surface extending parallel to an extension direction of the electrode lead, and the outlet of the gas discharge portion is located on a second side surface of the electrode lead, the second side surface being opposite from the first side surface and extending parallel to the extension direction of the electrode lead.
7 . The pouch-shaped battery cell according to claim 4 , wherein the gas discharge portion comprises a first gas discharge passage and a second gas discharge passage each having an I shape and overlapping each other in an X shape, an inlet of the first gas discharge passage is located on a first side surface of the electrode lead extending parallel to an extension direction of the electrode lead, and an outlet of the first gas discharge passage is located on a second side surface of the electrode lead opposite the first side surface and extending parallel to the extension direction of the electrode lead, and an inlet of the second gas discharge passage is located on the second side surface and an outlet of the second gas discharge passage is located on the first side surface.
8 . The pouch-shaped battery cell according to claim 1 , wherein the electrode lead is bent at an outside of the battery case, the electrode lead comprises an inner lead portion disposed penetrating a sealed portion of the battery case and an outer lead portion extending from the inner lead portion and located outside of the sealed portion of the battery case, and an outlet of the gas discharge portion is located at a surface of the outer lead.
9 . A battery pack comprising: a pack case having two or more pouch-shaped battery cells received therein, each of the two or more pouch-shaped battery cells being the pouch-shaped battery cell according to claim 1 ; a sensor member disposed in the pack case and outside of the two or more pouch-shaped battery cells, the sensor member being configured to detect a gas discharged from the two or more pouch-shaped battery cells; and an alarm member configured to generate an alarm when the sensor member detects the gas.
10 . The battery pack according to claim 9 , wherein the gas detected by the sensor member comprises different types of gases and where in the alarm member is configured to generate a different alarm for each of the different types of gases.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application is a national stage entry under 35 U.S.C. § 371 of International Application No. PCT/2021/015542, filed on Nov. 1, 2021, which claims priority to Korean Patent Application No. 10-2020-0144469, filed on Nov. 2, 2020, the disclosures of which are hereby incorporated herein by reference in their entireties. The present invention relates to a pouch-shaped battery cell including an electrode lead capable of maintaining uniform internal pressure and a battery pack including the same. More particularly, the present invention relates to a pouch-shaped battery cell including an electrode lead capable of maintaining uniform internal pressure in order to prevent deformation and explosion of the pouch-shaped battery cell due to swelling of the pouch-shaped battery cell and a battery pack including the same. BACKGROUND ART A lithium secondary battery, which is capable of being charged and discharged, has been widely used as an energy source for wireless mobile devices or wearable devices, and has also been used as an energy source for electric vehicles. Depending on the kind or shape of a sheathing member, the lithium secondary battery may be classified as a pouch-shaped secondary battery made of a laminate sheet, a cylindrical secondary battery made of a metal can, or a prismatic secondary battery made of a metal can. The pouch-shaped secondary battery is in the spotlight as power for electric vehicles, which requires a high-output, high-capacity energy source, since the pouch-shaped secondary battery can be manufactured in various sizes, is lightweight, and has high energy density. For the lithium secondary battery, the temperature of an electrode assembly and an electrical connection member is increased by heat generated during continuous charging and discharging thereof. At a high temperature, an electrolytic solution in the lithium secondary battery is decomposed, whereby gas is generated, which swells the lithium secondary battery. For a battery pack configured such that a plurality of battery cells is fixed in a case, swollen battery cells are further compressed in the limited case, whereby a danger of ignition and explosion is increased. In order to solve the above problem, a separate space configured to receive gas generated in the lithium secondary battery may be provided in a battery cell. However, this has the disadvantage of reducing the energy density. Meanwhile, gas discharged from the lithium secondary battery contains a substance harmful to a human body, and it is necessary to prevent generation of such a harmful gas in order to maintain user's health and to prevent a personal accident. Patent Document 1 discloses a battery pack including a battery cell, which includes an electrode assembly including a positive electrode tab and a negative electrode tab and a pouch case configured to hermetically seal the electrode assembly such that the positive electrode tab and the negative electrode tab are exposed; a gas sensor disposed in the vicinity of the positive electrode tab and the negative electrode tab, the gas sensor being configured to sense leakage of an electrolytic solution; and a protection circuit module configured to interrupt charging and discharging of the battery cell and to forcibly discharge the battery cell in response to an output signal of the gas sensor. Patent Document 1 includes the gas sensor configured to sense leaked gas but does not suggest a structure capable of reducing the internal pressure of the pouch case that swells. Patent Document 2 discloses a valve that forms a path through which the inside and the outside of a packaging container communicate with each other, wherein the valve includes a breakage valve configured to be open when the internal pressure of the packaging container is increased, a check valve configured to discharge gas in the packaging container to the outside, and a mounting portion configured to at least partially settle the path, the mounting portion being fixed to the packaging container in a state of being fitted in a film constituting the packaging container. Patent Document 2 includes the breakage valve that is primarily open and the check valve located outside, wherein the structure of the valve is complicated, and a separate space is necessary to use the valve. In the case in which the valve is applied to a battery, energy density of the battery may be reduced. In addition, since sealability of a battery cell at the portion to which the valve is added is unreliable, there is a problem in that the battery cell including the valve further requires a portion configured to verify overall sealability of the battery cell. Therefore, there is a need for technology capable of preventing swelling of a battery cell due to gas that is naturally or abnormally generated during use of a lithium secondary battery and rapidly sensing leakage of a substance harmful to the human body, thereby securing safety of