KR-20260065541-A - COMPOSITION FOR INSULATING LAYER OF CURRENT COLLECTOR FOR LITHIUM-ION SECONDARY BATTERY AND METHOD FOR PRODUCING THE SAME, CURRENT COLLECTOR HAVING INSULATING LAYER FOR LITHIUM-ION SECONDARY BATTERY, ELECTRODE FOR LITHIUM-ION SECONDARY BATTERY, AND LITHIUM-ION SECONDARY BATTERY

Abstract

[Problem] To provide a composition for an insulating layer capable of forming an insulating layer with excellent adhesion to the current collector and anti-blocking properties for a lithium-ion secondary battery current collector. [Solution] A composition for an insulating layer of a current collector for a lithium-ion secondary battery, comprising a resin (A) having at least one bonding group selected from the group consisting of urethane groups, urea groups, amide groups, and imide groups, and a non-aqueous solvent, wherein the total concentration of bonding groups in the resin (A) is 500 to 10000 mmol/kg.

Inventors

• 장 치
• 마쓰오카 류이치
• 기자키 다케오

Assignees

• 디아이씨 가부시끼가이샤

Dates

Publication Date

20260508

Application Date

20251029

Priority Date

20241030

Claims (17)

1. As a composition for an insulating layer of a current collector for a lithium-ion secondary battery, A resin (A) having at least one linking group selected from the group consisting of urethane groups, urea groups, amide groups, and imide groups, and a non-aqueous solvent, comprising A composition for an insulating layer, wherein the total concentration of the linkers in the resin (A) is 500 to 10000 mmol/kg.
2. In claim 1, A composition for an insulating layer, wherein the total concentration of the linkers in the resin (A) is 1000 to 8000 mmol/kg.
3. In claim 1, A composition for an insulating layer, wherein the above resin (A) comprises at least one resin selected from the group consisting of polyurethane resin, polyurea resin, and polyurethaneurea resin.
4. In claim 1, A composition for an insulating layer, wherein the above resin (A) has an aromatic ring.
5. In claim 4, A composition for an insulating layer, wherein the concentration of aromatic rings in the above resin (A) is 1000 to 8000 mmol/kg.
6. In claim 1, The above resin (A) is a composition for an insulating layer comprising a polyolefin structure.
7. In claim 6, A composition for an insulating layer, wherein the above polyolefin structure comprises the structure of at least one polyolefin selected from the group consisting of polybutadiene, polyisoprene, and hydrogenated derivatives thereof.
8. In claim 6, A composition for an insulating layer, wherein the content of the above polyolefin structure is 10 to 80 mass% based on the total mass of the resin (A).
9. In claim 1, A composition for an insulating layer, wherein the weight average molecular weight of the above resin (A) is 10,000 to 1,000,000.
10. In claim 1, A composition for an insulating layer, wherein the above-mentioned non-aqueous solvent comprises at least one solvent selected from the group consisting of N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, and dimethyl sulfoxide.
11. In claim 1, A composition for an insulating layer, additionally containing an inorganic filler.
12. In claim 1, A composition for an insulating layer, wherein the insulating layer is formed along the boundary between the region on the current collector where the electrode active material layer is formed and the region where the electrode active material layer is not formed.
13. A method for manufacturing a composition for an insulating layer as described in any one of claims 1 to 12, wherein A manufacturing method comprising at least one of the following (1) to (5) processes. (1) Process of reacting polyol and polyisocyanate (2) Process of reacting polyamine and polyisocyanate (3) Process of reacting polyol with polyisocyanate and polyamine (4) Process of reacting polycarboxylic acid with polyamine (5) A process of reacting an acid anhydride having a carboxyl group with a polyisocyanate
14. A current collector having an insulating layer for a lithium-ion secondary battery, comprising an insulating layer formed from an insulating layer composition described in any one of claims 1 to 12.
15. In claim 14, A current collector having an insulating layer for a lithium-ion secondary battery, which is a positive electrode.
16. An electrode for a lithium-ion secondary battery comprising a current collector as described in claim 14 and an electrode active material layer.
17. A lithium-ion secondary battery having the electrode described in claim 16.

Description

Composition for an insulating layer of a current collector for a lithium-ion secondary battery and method for producing the same, current collector having an insulating layer for a lithium-ion secondary battery, electrode for a lithium-ion secondary battery, and lithium-ion secondary battery The present disclosure relates to a composition for an insulating layer of a current collector for a lithium-ion secondary battery and a method for manufacturing the same, a current collector having an insulating layer for a lithium-ion secondary battery, an electrode for a lithium-ion secondary battery, and a lithium-ion secondary battery. The electrodes (positive and negative electrodes) of a lithium-ion secondary battery typically comprise a current collector made of metal foil or the like, and an electrode active material layer installed on the current collector by means of a press or the like. On the current collector of the electrode, a region where the electrode active material layer is not formed is provided to secure a current path; various technologies are being considered to prevent short circuits caused by the exposure of the current collector in this region. As one of the aforementioned techniques, for example, a method of covering the exposed portion of a current collector using insulating tape is known. However, in addition to poor workability (productivity), there were concerns regarding insulating tape, such as peeling over time and degradation of battery performance due to the tape becoming too thick. In particular, when the electrode active material layer is formed in a long length, such as in electrodes using a current collector without a current collecting tab (so-called tabless current collector), the area to be insulated becomes long, making it difficult to adhere the insulating tape. In contrast, a technique for forming an insulating layer on an exposed portion of a current collector using a composition such as an insulating paste has been proposed (see, for example, Patent Document 1). Exemplary embodiments of the present disclosure are described below. However, the present disclosure is not limited to the following embodiments. Furthermore, in this specification, numerical ranges indicated by "~" represent a range that includes the values described before and after "~" as minimum and maximum values, respectively. Also, unless specifically stated otherwise, the units of the values described before and after "~" are the same. Additionally, the individually described upper and lower limits may be combined arbitrarily. <Composition for Insulating Layer> One embodiment of the present disclosure is a composition for an insulating layer of a current collector for a lithium-ion secondary battery, comprising a resin (hereinafter referred to as “Resin (A)”) having at least one bonding group selected from the group consisting of urethane groups, urea groups, amide groups, and imide groups (hereinafter collectively referred to as “bonding group (X)”), and a non-aqueous solvent, wherein the total concentration of bonding groups (X) in the resin (A) is 500 to 10000 mmol/kg (hereinafter referred to as “Composition (I)”). Composition (I) is used to form an insulating layer on a current collector for a lithium-ion secondary battery. The insulating layer is installed in an area on the current collector for the lithium-ion secondary battery where the electrode active material layer is not formed, and by covering the exposed portion of the current collector in said area, the current collector is insulated to prevent the occurrence of a short circuit. Since the short circuit can occur due to contact between lithium precipitated at the end of the negative electrode active material layer and the positive electrode current collector, the insulating layer is formed, for example, along the boundary between the area where the electrode active material layer is formed and the area where the electrode active material layer is not formed (particularly the boundary on the positive side). In some cases, a portion of the insulating layer may be formed on the electrode active material layer beyond said boundary (for example, on the surface of the portion along said boundary). According to composition (I), an insulating layer with excellent adhesion to the current collector and anti-blocking properties can be formed for a current collector for a lithium-ion secondary battery. Whether the layer formed from composition (I) becomes an insulating layer (i.e., the layer has insulating properties) can be confirmed by measuring the cell capacity using the method described in the example. If the cell capacity measured by the method of the example is 20 mAh/g or less, it can be said that the layer formed from composition (I) has insulating properties. In addition, the evaluation layer is formed by applying composition (I) onto an aluminum foil such that the thickness after drying is 20 μm, and drying it at 140°C for 2 hours. Composition