US-12620682-B2 - Jelly-roll electrode assembly and secondary battery comprising the same

US12620682B2US 12620682 B2US12620682 B2US 12620682B2US-12620682-B2

Abstract

A jelly-roll electrode assembly includes a cathode sheet, an anode sheet, and a separator interposed between the cathode sheet and the anode sheet, the cathode sheet, the anode sheet, and the separator being wound together. An outermost side of the jelly-roll electrode assembly includes a non-coated portion on which no active material layer is provided on the anode sheet. A swelling tape is located on an inner surface of the non-coated portion of the anode sheet facing toward a central part of the jelly-roll electrode assembly. One or more embossments or wrinkles are provided in the swelling tape.

Inventors

Inbok PARK

Assignees

LG ENERGY SOLUTION, LTD.

Dates

Publication Date: 20260505
Application Date: 20221124
Priority Date: 20211124

Claims (17)

1 . A jelly-roll electrode assembly comprising a cathode sheet, an anode sheet, and a separator interposed between the cathode sheet and the anode sheet, wherein the cathode sheet, the anode sheet, and the separator are wound together, wherein an outermost side of the jelly-roll electrode assembly includes a non-coated portion on which no active material layer is provided on the anode sheet, wherein a swelling tape is located on an inner surface of the non-coated portion of the anode sheet facing towards a central part of the jelly-roll electrode assembly, and wherein one or more embossments or wrinkles are provided in the swelling tape, wherein: air is trapped in the one or more embossments or wrinkles of the swelling tape.
2 . The jelly-roll electrode assembly according to claim 1 , wherein: the anode sheet includes a coated portion having an active material layer provided on the anode sheet, and the swelling tape is attached to a part of the inner surface of the non-coated portion of the anode sheet and a part of the coated portion of the anode sheet at a boundary surface between the non-coated portion and the coated portion of the anode sheet.
3 . The jelly-roll electrode assembly according to claim 1 , wherein: the swelling tape is attached to only a part of the inner surface of the non-coated portion of the anode sheet.
4 . The jelly-roll electrode assembly according to claim 1 , wherein: the swelling tape covers 10% to 90% of a total area of the inner surface of the non-coated portion of the anode sheet.
5 . The jelly-roll electrode assembly according to claim 1 , wherein: the anode sheet includes a coated portion having an active material layer provided on the anode sheet, and the non-coated portion of the anode sheet on which the swelling tape is located faces the coated portion of the anode sheet when wound.
6 . The jelly-roll electrode assembly according to claim 1 , wherein: the non-coated portion of the anode sheet contacted by the swelling tape has one or more embossments or wrinkles corresponding to the swelling tape.
7 . The jelly-roll electrode assembly according to claim 6 , wherein: the one or more embossments or wrinkles of the non-coated portion of the anode sheet are formed by the one or more embossments or wrinkles of the swelling tape.
8 . The jelly-roll electrode assembly according to claim 1 , wherein: the one or more embossments have a regular pattern.
9 . The jelly-roll electrode assembly according to claim 8 , wherein: a roughness (Ra) of each of the one or more embossments is 0.1 mm to 20 mm.
10 . The jelly-roll electrode assembly according to claim 8 , wherein: a size of each of the one or more embossments is 10 μm to 5 mm.
11 . The jelly-roll electrode assembly according to claim 8 , wherein: the one or more embossments include two or more embossments, and a distance between adjacent embossments is 50 μm to 5 mm.
12 . The jelly-roll electrode assembly according to claim 1 , wherein: the one or more wrinkles have irregular shapes.
13 . A method for manufacturing the jelly-roll electrode assembly of claim 1 , the method comprising: an electrode assembly manufacturing step of winding the cathode sheet, the anode sheet, and the separator interposed between the cathode sheet and the anode sheet such that the non-coated portion of the anode sheet is on the outermost side of the jelly-roll electrode assembly; and a tape attachment step of attaching to the inner surface of the non-coated portion of the anode sheet to the swelling tape having the one or more embossments or attaching the swelling tape to the inner surface of the non-coated portion of the anode sheet so as to form the one or more wrinkles.
14 . The method for manufacturing the jelly-roll electrode assembly according to claim 13 , wherein: attaching the swelling tape so as to form the one or more wrinkles includes one of: attaching a part of the swelling tape in an unattached form when attaching the swelling tape; applying vibration to an attachment portion of the swelling tape to induce micro-bubbles or micro-wrinkles; or making a central part of a suction pad for attaching the swelling tape into a detachment state to form a vacuum space, thereby inducing generation of bubbles during attachment.
15 . A method for manufacturing the jelly-roll electrode assembly of claim 1 , the method comprising: a tape attachment step of attaching the swelling tape having the one or more embossments onto the non-coated portion of one end of the anode sheet, or attaching the swelling tape so as to form the one or more wrinkles; and an electrode assembly manufacturing step of winding the cathode sheet, the anode sheet, and the separator interposed between the cathode sheet and the anode sheet such that the inner surface faces toward the central part of the jelly-roll electrode assembly and is at the outermost side of the jelly-roll electrode assembly.
16 . The method for manufacturing the jelly-roll electrode assembly according to claim 15 , wherein: attaching the swelling tape so as to form the one or more wrinkles includes: attaching a part of the swelling tape in an unattached form when attaching the swelling tape; applying vibration to an attachment portion of the swelling tape to induce micro-bubbles or micro-wrinkles; or making a central part of a suction pad for attaching the swelling tape into a detachment state to form a vacuum space, thereby inducing the generation of bubbles during attachment.
17 . A secondary battery comprising the jelly-roll electrode assembly according to claim 1 .

Description

TECHNICAL FIELD Cross Citation with Related Application(s) This application claims the benefit of Korean Patent Application No. 10-2021-0163387 filed on Nov. 24, 2021 and Korean Patent Application No. 10-2022-0158763 filed on Nov. 23, 2022 in the Korean Intellectual Property Office, the entire contents of which are incorporated herein by reference. The present disclosure relates to a jelly-roll electrode assembly and a secondary battery comprising the same. BACKGROUND With the technology development and increased demand for mobile devices, demand for secondary batteries as energy sources have been rapidly increasing. 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 the battery case, a secondary battery is classified into a cylindrical battery where an electrode assembly is mounted in a cylindrical metal can, a prismatic battery where an electrode assembly is mounted in a prismatic metal can, and a pouch-type battery where an electrode assembly is mounted in a pouch type case made of an aluminum laminate sheet. Among them, the cylindrical battery has an advantage that it has a relatively large capacity and is structurally stable. The electrode assembly mounted in the battery case is an electricity-generating device, having a cathode/separator/anode laminate structure, which can be charged and discharged. The electrode assembly is classified into a jelly-roll type, a stacked type, and a stack/folding type. The jelly-roll type is a shape in which a cathode and an anode, each made of an active material-coated long sheet, is wound with a separator interposed between them, the stacked type is a shape in which a plurality of cathodes and a plurality of anodes each having a predetermined size are sequentially stacked in a state where a separator is interposed therebetween, and a stack/folding type is a combination of a jelly-roll type and a stack type. Of these, the jelly-roll-type electrode assembly has advantages that manufacture is easy and the energy density per weight is high. Therefore, in recent years, as the need for batteries to achieve high capacity and high output has increased, in the case of a cylindrical battery, optimization is underway by changing the thickness of current collectors or separators, and the size or shape of cans, top caps and the like in order to put a large quantity of electrodes in a limited space. As one of the methods thereof, a method of utilizing copper as an outer tab as an anode current collector has been proposed. That is, the tab and separator on the outside are removed, and the copper current collector physically abuts on the cylindrical can so that the current flows out. Through this method, the input amount of the separator and the input amount of the tab can be reduced, and the outer diameter can be slightly reduced to exhibit the effects of securing space and reducing costs, and the secured space can be utilized to increase capacity or improve output. In addition, since the copper current collector directly abuts on the can, the area of transferring heat is increased, and thus, the heat generation level can be improved. However, when copper is actually exposed on the outer shell portion, one or two points having a larger outer diameter abut on the can in accordance with the circularity of the jelly roll, which reduces the effect than previously expected. In order to improve this, the contact level was improved by using a swelling tape that has the property of swelling up when reacting with the electrolyte, but when attaching in the manufacturing process, an air trap is generated, which causes a problem that the outer diameter increases and thus the productivity decreases. Therefore, it is necessary to develop a jelly-roll electrode assembly and secondary battery technology that can solve these problems. DETAILED DESCRIPTION OF THE INVENTION Technical Problem It is an object of the present disclosure to provide a jelly-roll electrode assembly that can uniformly control an air trap generated by the attachment of the swelling tape, thereby improving the contact level with a battery case of the outermost side anode non-coated portion while solving the problem of the outer diameter increase due to the air trap, and a secondary battery comprising the same. The objects of the present disclosure are not limited to the aforementioned objects, and other objects which are not mentioned herein should be clearly understood by those skilled in the art from the following detailed description and the accompanying drawings. Technical Solution According to one embodiment of the present disclosure, there is provided a jelly-roll electrode assembly comprising a cathode sheet, an anode sheet,