US-12620658-B2 - Pouch battery cell and battery module including the same

US12620658B2US 12620658 B2US12620658 B2US 12620658B2US-12620658-B2

Abstract

A pouch battery cell according to one embodiment of the present disclosure includes an electrode assembly including a cathode, an anode and a separator interposed between the cathode and the anode; and a battery case to which the electrode assembly is attached, wherein the battery case comprises an upper case, a lower case, and a receiving portion formed between the upper case and the lower case, wherein the battery case is formed with sealing portions in which outer peripheral surfaces of the upper case and the lower case are heat-sealed to each other, and wherein one end of at least a part of the sealing portions is recessed in the inside of the battery case.

Inventors

In Gu AN
Ki Woong Kim

Assignees

LG ENERGY SOLUTION, LTD.

Dates

Publication Date: 20260505
Application Date: 20210909
Priority Date: 20200928

Claims (14)

1 . A pouch battery cell comprising: an electrode assembly including a cathode, an anode and a separator interposed between the cathode and the anode; and a battery case in which the electrode assembly is disposed, wherein the battery case comprises an upper case, a lower case, and a receiving portion formed between the upper case and the lower case, wherein the battery case is formed with sealing portions at which outer peripheral surfaces of the upper case and the lower case are heat-sealed to each other wherein a first end of at least a part of the sealing portions is recessed towards an inside of the battery case, and wherein a sealing extension portion of the upper case and a sealing extension portion of the lower case have a shape concavely recessed in the inside of the pouch battery cell.
2 . The pouch battery cell according to claim 1 , wherein: a second end of the at least a part of the sealing portions is bent and is disposed adjacent to a side surface of the upper case or the lower case.
3 . The pouch battery cell according to claim 2 , wherein: the second end of the at least a part of the sealing portions is located closer to the electrode assembly than a part of a side surface of the battery case.
4 . The pouch battery cell according to claim 1 , wherein: among the sealing portions, the first end of the sealing portion formed on the outer peripheral surface located at first and second opposite sides of the outer peripheral surface on which an electrode lead of the electrode assembly is formed is recessed towards the inside of the battery case.
5 . The pouch battery cell according to claim 1 , wherein: among the sealing portions, the first end of a pair of the sealing portions facing each other on first and second opposite side surfaces of the battery case is recessed towards the inside of the battery case.
6 . The pouch battery cell according to claim 5 , wherein: a second end of a pair of the sealing portions is bent and is disposed adjacent to a side surface of the upper case or the lower case.
7 . The pouch battery cell according to claim 6 , wherein: the second end of the pair of the sealing portions is located closer to the electrode assembly than a part of a side surface of the battery case.
8 . The pouch battery cell according to claim 5 , wherein: the pair of the sealing portions are respectively formed on the outer peripheral surface located at first and second opposite sides of the outer peripheral surface on which at least one electrode lead of the electrode assembly is formed.
9 . The pouch battery cell according to claim 1 , wherein: the receiving portion comprises a first receiving portion formed in the upper case and a second receiving portion formed in the lower case, and the first receiving portion and the second receiving portion are together recessed to a combined length corresponding to the height of the electrode assembly.
10 . The pouch battery cell according to claim 1 , wherein: the battery case is composed of a pouch type case of a laminated sheet including a resin layer and a metal layer.
11 . The pouch battery cell according to claim 1 , wherein: the upper case and the lower case have respective shapes that are symmetrical to each other.
12 . A battery module comprising the pouch battery cell according to claim 1 .
13 . The battery module according to claim 12 , further comprising a metal plate located on at least one side surface of the pouch battery cell.
14 . The pouch battery cell according to claim 2 , wherein: a second end of the at least a part of the sealing portions is located inside the battery case with respect to the side surface of the battery case.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application is a national stage entry under 35 U.S.C. § 371 of International Application No. PCT/KR2021/012307, filed on Sep. 9, 2021, which claims priority to Korean Patent Application No. 10-2020-0126271, filed on Sep. 28, 2020, and Korean Patent Application No. 10-2021-0116871, filed on Sep. 2, 2021, the disclosures of which are hereby incorporated herein by reference in their entireties. TECHNICAL FIELD The present disclosure relates to a pouch battery cell and a battery module including the same, and more particularly to a pouch battery cell that is improved in dimensional stability, delays a venting phenomenon caused by gas generated inside the battery cell, and prevents electrical corrosion of the sealing portion, and a battery module including the same. BACKGROUND Along with the increase of technology development and demands for mobile devices, the demand for batteries as energy sources is increasing rapidly. In particular, a secondary battery has attracted considerable attention as an energy source for power-driven devices, such as an electric bicycle, an electric vehicle, and a hybrid electric vehicle, as well as an energy source for mobile devices, such as a mobile phone, a digital camera, a laptop computer and a wearable device. Based on the shape of a battery case, such a secondary battery is classified into a cylindrical battery where an electrode assembly is built in a cylindrical metal can, a prismatic battery where an electrode assembly is built in a prismatic metal can, and a pouch type battery where an electrode assembly is built in a pouch type case formed of an aluminum laminate sheet. Here, the electrode assembly built in the battery case is a power generating element, having a structure including a cathode, an anode, and a separator interposed between the cathode and the anode, and capable of being charged and discharged. The electrode assembly may be classified as a jelly-roll type electrode assembly configured to have a structure in which a long sheet-type cathode and a long sheet-type anode, which are coated with active materials, are wound with a separator being interposed between the cathode and the anode, and a stacked type electrode assembly configured to have a structure in which a plurality of cathodes and anodes are sequentially stacked with separators being interposed between the cathodes and the anodes. Among them, particularly, a pouch type battery, having a structure in which a stacked type or a stacked/folded type electrode assembly is built in a pouch type battery case formed of an aluminum laminate sheet, has advantages such as low manufacturing costs, small weight, and easy shape deformation, and therefore, is gradually increasing in the amount of its usage. FIG. 1 is a front view showing a conventional pouch battery cell. Referring to FIG. 1, the pouch battery cell 10 includes a battery case 14 including an upper case 12 and a lower case 13, wherein an electrode assembly (not shown) is built in the upper case 12 and the lower case 13. Further, the upper case 12 and the lower case 13 include a sealing portion 15 formed by heat-sealing the outer peripheral surfaces of the upper case 12 and the lower case 13 in order to seal the electrolyte solution contained with the electrode assembly. FIG. 2 is an enlarged view showing a side portion of the pouch battery cell of FIG. 1. FIG. 2(a) is a view before expansion of the battery cell, and FIG. 2(b) is a view after expansion of the battery cell. FIG. 3 is a diagram showing an expansion region A in which the side portion of the pouch battery cell of FIG. 1 is expanded. Referring to FIG. 1, the pouch battery cell 10 is used by being press-bonded to the metal plate 20 located at both sides of the pouch battery cell 10 when assembling a battery module or battery pack. Referring to FIGS. 2 and 3, the pouch battery cell 10 generates a large amount of gas in the inside of the battery cell during the charging and discharging process, whereby high pressure is induced inside the sealed case, which causes a swelling phenomenon. The metal plate 20 interrupts the expansion of the pouch battery cell 10 to the upper and lower portions, so that one side portion of the pouch battery cell 10 can be expanded like the expansion region A. However, referring to FIG. 3, in the case of the conventional pouch battery cell 10, when a swelling phenomenon occurs in one side portion of the pouch battery cell 10, the one side portion of the pouch battery cell 10 deviates from the dimensions of the metal plate 20 located at both sides of the pouch battery cell 10. Thereby, there is a high possibility that the sealing portion 15 of the pouch battery cell 10 is damaged, which causes a problem that the internal gas is vented to the outside, and external gas or moisture is flowed into the battery cell, thereby degrading battery performance. In addition to this, referring to FIG. 3, the sealing portion 15 is exposed