JP-7855831-B2 - Electrode assembly, method for manufacturing the same, and battery cell containing the same

JP7855831B2JP 7855831 B2JP7855831 B2JP 7855831B2JP-7855831-B2

Inventors

リー、ビョンキュ
ジュン、スタエク
チュン、ジョーヨン
キム、ジンゴン
ジュン、ウージュン
キム、セウンイル

Assignees

エルジーエナジーソリューションリミテッド

Dates

Publication Date: 20260511
Application Date: 20230502
Priority Date: 20220510

Claims (12)

An electrode assembly in which electrodes and a first separation membrane sheet are alternately stacked, The electrode includes a first electrode and a second electrode. The first separation membrane sheet has a zigzag shape formed by folding at least twice, The length of the second electrode is shorter than the length of the first electrode. The present invention includes a molded member located between the first separation membrane sheet enclosing the second electrode and the outer surface of the electrode assembly, and between the second electrode and the outer surface of the electrode assembly, The aforementioned molded member is Located between the first separation membrane sheet enclosing the first electrode and the outer surface of the electrode assembly, and between the first electrode and the outer surface of the electrode assembly, Of the two sides of the first electrode, the side opposite to the side covered by the first separation membrane sheet is in contact with the molded member. An electrode assembly wherein the side of the second electrode opposite to the side covered by the first separation membrane sheet is in contact with the molded member .
The electrode assembly according to claim 1 , wherein the molded member covers the entire side of the first electrode opposite to the side covered by the first separation membrane sheet.
Of the two sides of the first electrode, the side covered by the first separation membrane sheet is in contact with the first separation membrane sheet. The electrode assembly according to claim 1 , wherein one of the two sides of the second electrode is enclosed by the first separation membrane sheet and is in contact with the first separation membrane sheet.
The first tolerance is the distance that the side opposite to the side of the first electrode that is covered by the first separation membrane sheet protrudes from the first separation membrane sheet that covers the second electrode, and the second tolerance is the distance that the first separation membrane sheet that covers the first electrode protrudes from the side of the second electrode that is opposite to the side of the second electrode that is covered by the first separation membrane sheet. The electrode assembly according to claim 1 , wherein the second tolerance is greater than the first tolerance.
The aforementioned molded member is The electrode assembly according to claim 4 , satisfying the first tolerance and the second tolerance.
The aforementioned molded member is The electrode assembly according to claim 5 , wherein the area protruding from one side surface of the electrode assembly on which the first tolerance is formed is greater than the area protruding from the other side surface of the electrode assembly on which the second tolerance is formed.
Further comprising a second separation membrane sheet, The electrode assembly according to claim 1, wherein the second separation membrane sheet encloses the entire outer surface of the electrode assembly and forms the outer surface of the electrode assembly.
A step of manufacturing an electrode assembly by alternately stacking a first electrode, a second electrode, and a first separation membrane sheet; The steps include: placing a moldable material on the electrode assembly; and wrapping the outer surface of the electrode assembly with a second separation membrane sheet. The first separation membrane sheet has a zigzag shape formed by folding at least twice, The step of placing the moldable material in the electrode assembly includes placing the moldable material between the first separation membrane sheet enclosing the second electrode and the outer surface of the electrode assembly, and between the second electrode and the outer surface of the electrode assembly . The step of placing the moldable material in the electrode assembly includes placing the moldable material between the first separation membrane sheet enclosing the first electrode and the outer surface of the electrode assembly, and between the first electrode and the outer surface of the electrode assembly. Of the two sides of the first electrode, the side opposite to the side covered by the first separation membrane sheet is in contact with the moldable material. A method for manufacturing an electrode assembly wherein the side of the second electrode opposite to the side covered by the first separation membrane sheet is in contact with the moldable material .
The method for manufacturing an electrode assembly according to claim 8 , further comprising the step of heating and pressurizing the electrode assembly after the step of placing the moldable material on the electrode assembly.
The electrode assembly includes a first tolerance, which is the distance that the side of the first electrode opposite to the side covered by the first separation membrane sheet protrudes from the first separation membrane sheet covering the second electrode, and a second tolerance, which is the distance that the first separation membrane sheet covering the first electrode protrudes from the side of the second electrode opposite to the side covered by the first separation membrane sheet. The electrode assembly manufacturing method according to claim 8 , wherein the second tolerance is even greater than the first tolerance.
The aforementioned moldable material is A method for manufacturing an electrode assembly according to claim 10 , which satisfies the first tolerance and the second tolerance.
A battery cell comprising an electrode assembly according to any one of claims 1 to 7 .

Description

Mutual Citation with Related Applications This application claims priority rights based on Korean Patent Application No. 10-2022-0057202 dated May 10, 2022, and Korean Patent Application No. 10-2023-0054961 dated April 26, 2023, and all content disclosed in the documents of said Korean patent applications is incorporated herein by reference. This invention relates to an electrode assembly, a method for manufacturing the same, and a battery cell containing the same. More specifically, it relates to an electrode assembly in which electrodes and separation membrane sheets are alternately stacked in a Z-folding configuration, and a battery cell containing the same, which can prevent overhangs that occur when the positive electrode deviates from the negative electrode and disrupts the alignment. The invention also relates to a method for manufacturing the same and a battery cell containing the same. Generally, types of rechargeable batteries include nickel-cadmium batteries, nickel-metal hydride batteries, lithium-ion batteries, and lithium-ion polymer batteries. These rechargeable batteries are used not only in small products such as digital cameras, P-DVDs, MP3 players, mobile phones, PDAs (registered trademarks), portable game devices, power tools, and e-bikes, but also in large products requiring high output, such as electric vehicles and hybrid vehicles, as well as in power storage devices and backup power storage devices that store surplus generated electricity and renewable energy. To manufacture such a secondary battery, first, an electrode active material slurry is applied to the positive electrode current collector and the negative electrode current collector to produce the positive and negative electrodes. These are then stacked on both sides of a separator to form an electrode assembly of a predetermined shape. Finally, the electrode assembly is placed in a battery case, and after the electrolyte is injected, it is sealed. Electrode assemblies are classified into various types. For example, there is the simple stack type, in which positive electrodes, separator membranes, and negative electrodes are simply stacked in a cross pattern without manufacturing unit cells; the lamination and stack type (L&S), in which unit cells are first manufactured using positive electrodes, separator membranes, and negative electrodes, and then these unit cells are stacked; the stack and folding type (S&F), in which multiple unit cells are attached to one side of a separator membrane sheet that is longer on one side at a distance from each other, and the separator membrane sheet is repeatedly folded from one end in the same direction; and the Z-folding type, in which multiple electrodes or unit cells are alternately attached to one side and the other side of a separator membrane sheet that is longer on one side, and the separator membrane sheet is folded from one end in a specific direction, and then folded in the opposite direction, repeating this method alternately. Of these, the Z-folding type has a high degree of alignment and electrolyte impregnation, and is frequently used these days. However, conventionally, when electrodes and separator membrane sheets were laminated in this Z-folding configuration, the portion of the separator membrane sheet surrounding the electrodes significantly exceeded the negative and positive electrodes. This design resulted in the positive electrode having a smaller surface area than the negative electrode, leading to a high probability of overhang, where the positive electrode deviates from the negative electrode and disrupts alignment. When this overhang occurs, it not only degrades the performance of the electrode assembly and the battery cell containing it, but also significantly increases the likelihood of defects such as short circuits. Therefore, it is necessary to develop an electrode assembly and a battery cell containing it that have a structure capable of preventing overhang, where the positive electrode deviates from the negative electrode and disrupts alignment. This figure shows the final electrode assembly according to one embodiment of the present invention.This is a cross-sectional view of the electrode assembly cut along the cutting line A-A' in Figure 1.This figure shows only a portion of the components of the electrode assembly shown in Figure 2.This figure shows how the molded member is formed on the electrode assembly shown in Figure 3.This figure shows how the outer surface of the electrode assembly (Figure 4) is formed.This figure shows a top view of the plane cut along the cutting line B-B' in Figure 1.This figure illustrates a method for manufacturing an electrode assembly according to another embodiment of the present invention.This figure illustrates a method for manufacturing an electrode assembly according to another embodiment of the present invention.This figure illustrates a method for manufacturing an electrode assembly according to another embodiment o