KR-20260067430-A - NEGATIVE ELECTRODE FOR LITHIUM SECONDARY BATTERY, LITHIUM SECONDARY BATTERY COMPRISING SAME AND METHOD FOR PREPARING NEGATIVE ELECTRODE FOR LITHIUM SECONDARY BATTERY

KR20260067430AKR 20260067430 AKR20260067430 AKR 20260067430AKR-20260067430-A

Abstract

The present invention relates to a negative electrode for a lithium secondary battery comprising: a negative electrode active material layer provided on at least one surface of a negative electrode current collector layer; a surface layer provided on the surface of the negative electrode active material layer; and an inner layer provided between the negative electrode active material layer and the surface layer, wherein the surface layer and the inner layer comprise one or more selected from the group consisting of polyvinyl-based polymers, polyamide-based polymers, polysilane-based polymers, polyfluorene-based polymers, polyaniline-based polymers, and combinations thereof, and wherein the inner layer and the surface layer comprise different polymers to suppress thermal runaway phenomena.

Inventors

현재익
이상현
김동혁
이용주

Assignees

주식회사 엘지에너지솔루션

Dates

Publication Date: 20260513
Application Date: 20241104

Claims (16)

A negative active material layer provided on at least one surface of a negative current collector layer; A surface layer provided on the surface of the above-mentioned cathode active material layer; and It includes an inner layer provided between the above-mentioned negative electrode active material layer and the above-mentioned surface layer, and A negative electrode for a lithium secondary battery, wherein the surface layer and the inner layer comprise one or more selected from the group consisting of polyvinyl-based polymers, polyamide-based polymers, polysilane-based polymers, polyfluorene-based polymers, polyaniline-based polymers, and combinations thereof, and the inner layer and the surface layer comprise different polymers.
In claim 1, A negative electrode for a lithium secondary battery, wherein the above surface layer comprises one or more selected from the group consisting of polyvinyl-based polymers, polyamide-based polymers, polyaniline-based polymers, and combinations thereof.
In claim 1, A negative electrode for a lithium secondary battery, wherein the inner layer comprises one or more selected from the group consisting of polysilane-based polymers, polyfluorene-based polymers, and combinations thereof.
In claim 1, The above negative electrode active material layer comprises two or more negative electrode active material layers, and The above inner layer is provided between at least one pair of adjacent negative active material layers, for a negative electrode for a lithium secondary battery.
In claim 1, The above inner layer is provided with n layers, and The above negative electrode active material layer is provided with n+1 layers, and A negative electrode for a lithium secondary battery, wherein the inner layer and the negative active material layer are alternately stacked, and n is an integer greater than or equal to 1.
In claim 1, A negative electrode for a lithium secondary battery, wherein the total thickness of the surface layer and the inner layer is 2 μm or less.
In claim 1, A negative electrode for a lithium secondary battery, wherein the thickness of the surface layer and the inner layer are each 1 nm or more and 400 nm or less.
In claim 1, A negative electrode for a lithium secondary battery, wherein the above inner layer is provided in 1 to 5 layers.
In claim 1, A negative electrode for a lithium secondary battery, wherein the above surface layer and the above inner layer are deposited on one surface of the above negative electrode active material layer.
Anode for lithium secondary battery; A negative electrode for a lithium secondary battery according to any one of claims 1 to 9; Separator; and A lithium secondary battery containing an electrolyte.
A battery module comprising a lithium secondary battery according to claim 10.
A battery pack comprising a lithium secondary battery according to claim 10.
A battery pack comprising a battery module according to claim 11.
(S1) A step of forming a first negative active material layer by coating a negative active material layer composition on at least one surface of a negative current collector layer; (S2) A step of forming an inner layer on the first negative electrode active material layer; (S3) A step of forming a second cathode active material layer by coating the cathode active material layer composition on the inner layer; and (S4) A step of forming a surface layer on the second negative electrode active material layer, and A method for manufacturing a negative electrode for a lithium secondary battery, wherein the above steps S2 to S3 are repeated at least once and no more than five times.
In claim 14, A method for manufacturing a negative electrode for a lithium secondary battery, wherein steps S1 to S4 above are performed by a roll-to-roll process.
In claim 14, A method for manufacturing a negative electrode for a lithium secondary battery, wherein the above S2 step and the above S4 step are performed by a deposition method using a roll-to-roll process.

Description

Negative electrode for lithium secondary battery, lithium secondary battery comprising the same, and method for preparing negative electrode for lithium secondary battery The present invention relates to a negative electrode for a lithium secondary battery, a lithium secondary battery including the same, and a method for manufacturing a negative electrode for a lithium secondary battery. Due to the rapid increase in the use of fossil fuels, there is a growing demand for alternative or clean energy. As part of this effort, the fields of power generation and energy storage utilizing electrochemical reactions are the most actively researched. Currently, a representative example of an electrochemical device utilizing such electrochemical energy is the secondary battery, and its scope of application is steadily expanding. With the increasing technological development and demand for mobile devices, the demand for secondary batteries as an energy source is rapidly rising. Among these secondary batteries, lithium-ion batteries, which possess high energy density and voltage, long cycle life, and low self-discharge rates, have been commercialized and are widely used. Furthermore, active research is being conducted on methods to manufacture high-density electrodes with higher energy density per unit volume for use in such high-capacity lithium-ion batteries. Generally, a secondary battery includes a positive electrode, a negative electrode, a separator interposed between the positive and negative electrodes, and an electrolyte. Additionally, electrodes such as the positive and negative electrodes may have an electrode active material layer provided on a current collector. Meanwhile, thermal runaway reactions caused by various factors such as defects in lithium secondary batteries, external impact, overcharging, and over-discharging are becoming a problem as they cause positive feedback that generates greater heat, such as swelling of the battery, voltage rise, and electrolyte temperature rise, leading to ignition or explosion accidents. Accordingly, various studies are being conducted to suppress thermal runaway reactions in lithium secondary batteries. FIGS. 1 to 3 are drawings showing a stacked structure of a negative electrode for a lithium secondary battery according to one embodiment of the present invention. FIG. 4 is a flowchart illustrating a method for manufacturing a negative electrode for a lithium secondary battery according to one embodiment of the present invention. FIG. 5 is a diagram showing a stacked structure of a lithium secondary battery according to one embodiment of the present invention. Before describing the present invention, we will first define some terms. In this specification, when a part is described as "comprising" a certain component, it means that, unless specifically stated otherwise, it does not exclude other components but may include additional components. In this specification, terms such as “comprising,” “comprising,” or “having” are intended to specify the existence of the implemented features, numbers, steps, components, or combinations thereof, and should be understood as not excluding in advance the existence or addition of one or more other features, numbers, steps, components, or combinations thereof. In this specification, when a part such as a layer is described as being "above" or "on" another part, this includes not only the case where it is "immediately above" another part, but also the case where there is another part in between. Conversely, when a part is described as being "immediately above" another part, it means that there is no other part in between. Furthermore, being described as being "above" or "on" a reference part means being located above or below the reference part, and does not necessarily mean being located "above" or "on" in a direction opposite to gravity. In this specification, when it is stated that a certain member is provided on both sides of another member, it means that another member is provided on one side of a certain member, and another member is provided on another side corresponding to said one side. Furthermore, this includes not only cases where another member is in direct contact with one side of a certain member and its corresponding side, but also cases where another member exists between the two members. In this specification, 'p to q' means a range of 'p or more and q or less'. In this specification, terms such as “…part,” “device,” etc. refer to a unit that processes at least one function or operation. In this specification, "Dn" refers to the particle size distribution and represents the particle size (average particle size) at the n% point of the cumulative distribution of the number of particles according to particle size. That is, D 50 is the particle size at the 50% point of the cumulative distribution of the number of particles according to particle size, D 90 is the particle size at the 90% point of the cumulative distribut