KR-20260068009-A - BATTERY SEPARATOR BINDER COMPOSITION, BATTERY SEPARATOR, AND BATTERY

Abstract

The battery separator binder composition, battery separator, and battery of the present invention comprise a solvent; and polymer particles including a core portion and a shell portion; and can control the content of the core portion of the polymer particles, the glass transition temperature of the core portion, the glass transition temperature of the polymer particles, and the electrolyte swelling rate of the polymer particles.

Inventors

• 이금형
• 류동조
• 한정섭
• 조현주
• 김윤정

Assignees

• 주식회사 엘지화학

Dates

Publication Date

20260513

Application Date

20251104

Priority Date

20241104

Claims (19)

1. solvent; and Polymer particles comprising a core portion and a shell portion; Includes, The core content (weight%) of the above polymer particles is in the range of 20 to 70, and The glass transition temperature (°C) of the above core part is 60 or higher, and The glass transition temperature (°C) of the above polymer particles is in the range of 10 to 55, and A battery separator binder composition having an electrolyte swelling rate (weight%) of the above polymer particles of 400 or more.
2. In Article 1, A battery separator binder composition having an electrolyte gel content (weight%) of the above polymer particles of 70 or more.
3. In Article 1, A battery separator binder composition in which the average size (nm) of the polymer particles is within the range of 300 to 800.
4. In Article 1, A battery separator binder composition having an electrolyte swelling rate (weight%) of 200 or less in the core portion.
5. In Article 1, A battery separator binder composition having an electrolyte gel content (weight%) of 80 or more in the core portion.
6. In Article 1, A battery separator binder composition in which the average size (nm) of the core portion is within the range of 200 to 500.
7. In Article 1, The above core portion is a battery separator binder composition comprising a first unit of a styrene-based monomer, a second unit of a polar functional group monomer, and a third unit of a crosslinkable compound.
8. In Article 7, A battery separator binder composition in which the first unit content (weight%) of the core portion is 80 or more.
9. In Article 7, The above core portion is a battery separator binder composition further comprising a fourth unit of alkyl (meth)acrylate.
10. In Article 1, The above shell part comprises a fifth unit of an alkyl (meth)acrylate, a nitrile-based monomer, or a combination thereof; and a sixth unit of a styrene-based monomer, a monomer containing a polar functional group, or a combination thereof; a battery separator binder composition.
11. In Article 10, A battery separator binder composition in which the fifth unit content (weight%) of the shell portion is 50 or more.
12. In Article 1, The above solvent is a battery separator binder composition comprising an aqueous solvent.
13. In Article 1, Battery separator binder composition further comprising inorganic particles.
14. Substrate layer; and An outer layer located on one or both sides of the above-mentioned substrate layer; Includes, The above outer layer comprises a battery separator binder composition, and The above battery separator binder composition comprises a solvent; and polymer particles comprising a core portion and a shell portion; and The core content (weight%) of the above polymer particles is in the range of 20 to 70, and The glass transition temperature (°C) of the above core part is 60 or higher, and The glass transition temperature (°C) of the above polymer particles is in the range of 10 to 55, and A battery separator having an electrolyte swelling rate (weight%) of the above polymer particles of 400 or more.
15. In Article 14, The above outer layer is a battery separator comprising a dried product of the battery separator binder composition.
16. In Article 14, The above outer layer is a battery separator further comprising inorganic particles.
17. In Article 14, Further comprising: an inner layer located between the above substrate layer and the above outer layer; and The above inner layer is a battery separator containing inorganic particles.
18. It includes an anode, a cathode, a separator between the anode and the cathode, and an electrolyte, The above separator comprises a substrate layer; and an outer layer located on one or both sides of the substrate layer. The above outer layer comprises a battery separator binder composition, and The above battery separator binder composition comprises a solvent; and polymer particles comprising a core portion and a shell portion; and The core content (weight%) of the above polymer particles is in the range of 20 to 70, and The glass transition temperature (°C) of the above core part is 60 or higher, and A battery in which the glass transition temperature (°C) of the polymer particles is within the range of 10 to 55.
19. In Article 18, The above electrolyte is a battery comprising a carbonate-based solvent and a lithium salt.

Description

Battery separator binder composition, battery separator, and battery This document claims the benefit of the priority date of Application No. 10-2024-0154696 filed with the Korean Intellectual Property Office on November 4, 2024, and incorporates the entire contents thereof by reference. The present invention is a battery separator binder composition. The present invention is a battery separator. The present invention is a battery. A battery separator (hereinafter also referred to as the "separator") can be positioned between the positive and negative electrodes to prevent physical contact between them. Inorganic particles can be coated onto a porous film substrate to increase the durability of the separator. The porous film substrate may include a polyethylene-based porous film or a polypropylene-based porous film. A binder can increase the bonding strength between the coated inorganic particles or between the coated inorganic particles and the porous film substrate. Binders for separator membranes typically contain fluorine-based polymers such as polyvinylidene fluoride (PVDF). Separator membrane binders are usually acetone-based. Conventional membrane binders are disadvantageous for thin film formation and can cause environmental pollution problems. Attempts have been made to use acrylic polymers as binders for separators. However, acrylic polymers, which are susceptible to heat, tend to form a film due to the heat and pressure applied during the bonding process between the separator and the electrode. This film formation phenomenon blocks the interstitial volume between inorganic particles. When the pores of inorganic particles are blocked, it becomes difficult for charge carriers (e.g., lithium ions) to move within the battery. As a result, the electrical resistance of the battery increases. Figure 1 is an SEM image after coating of Example 6. Figure 2 is an SEM image of Example 6 after pressing. Figure 3 is an SEM image after electrolyte impregnation of Example 6. Figure 4 is an SEM image after coating of Example 7. Figure 5 is an SEM image of Example 7 after pressing. Figure 6 is an SEM image after electrolyte impregnation of Example 7. Figure 7 is an SEM image of Comparative Example 5 after coating. Figure 8 is an SEM image of Comparative Example 5 after pressing. Figure 9 is an SEM image of Comparative Example 5 after electrolyte impregnation. Figure 10 is an SEM image of Comparative Example 6 after coating. Figure 11 is an SEM image of Comparative Example 6 after pressing. Figure 12 is an SEM image of Comparative Example 6 after electrolyte impregnation. This document may use ordinal numbers such as “first” and “second” when referring to multiple components. There is no priority among the components. In this document, if a specific commercially available product is used as a certain ingredient, the characteristics of that ingredient may refer to the characteristics listed in the product's Technical Data Sheet (TDS) or Certification of Analysis. In this document, if the physical properties of a specific material vary depending on temperature and pressure, the measurement criteria for those physical properties may be 25 ℃ and 101.325 kPa. In this document, the numerical range “within the range of A to B” means “A or greater and B or less.” The numbers mentioned in this document are rounded values. For example, 1.5 is a number within the range of 1.45 to 1.54. The present document describes the invention in more detail below. One embodiment of the present invention is an embodiment of a battery separator binder composition. The battery separator binder composition can be coated onto a substrate layer constituting the battery separator to form a coating layer (outer layer). The battery separator binder composition can form an adhesive layer on the battery separator. The adhesive layer can attach the battery separator to the electrode. The above battery separator binder composition may include a solvent and a polymer. The polymer may be dispersed in the solvent. The polymer may be polymer particles dispersed in the solvent. The above solvent may include an aqueous solvent, a non-aqueous solvent, or a combination thereof. That is, the solvent may include an aqueous solvent, a non-aqueous solvent, or a mixed solvent of an aqueous solvent and a non-aqueous solvent. The above aqueous solvent may mean water or a solvent containing an excess amount of water. The water content (weight%) of the above aqueous solvent may be greater than 50, 60 or more, 70 or more, 80 or more, 90 or more, 95 or more, 99 or more, or 100. The above-mentioned non-aqueous solvent may include N-methyl-2-pyrrolidone (NMP), dimethylformamide (DMF), dimethylacetamide (DMAc), dimethyl sulfoxide (DMSO), tetrahydrofuran (THF), or a combination thereof. The battery separator binder composition of the present invention may include specific polymer particles. The battery separator binder composition of the present invention may include polyme