KR-20260068008-A - BATTERY SEPARATOR BINDER COMPOSITION, BATTERY SEPARATOR, AND BATTERY

KR20260068008AKR 20260068008 AKR20260068008 AKR 20260068008AKR-20260068008-A

Abstract

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

Inventors

조현주
한정섭
이금형

Assignees

주식회사 엘지화학

Dates

Publication Date: 20260513
Application Date: 20251104
Priority Date: 20241104

Claims (15)

solvent; and Polymer particles comprising a core portion and a shell portion; Includes, The glass transition temperature (°C) of the above polymer particles is in the range of 25 to 50, and The electrolyte gel content (weight%) of the above polymer particles is in the range of 70 to 90, and The glass transition temperature (°C) of the above core part is in the range of 70 to 99, and A battery separator binder composition in which the electrolyte gel content (weight%) of the core portion is within the range of 90 to 100.
In Article 1, A battery separator binder composition in which the electrolyte swelling rate (weight%) of the core portion is within the range of 100 to 200.
In Article 1, A battery separator binder composition in which the electrolyte swelling rate (weight%) of the polymer particles is within the range of 900 to 1350.
In Article 1, The above core portion comprises a first unit of a styrene-based monomer, a second unit of an alkyl (meth)acrylate, a third unit of a crosslinkable compound, and a fourth unit of a monomer containing a polar functional group, forming a battery separator binder composition.
In Paragraph 4, A battery separator binder composition in which the first unit content (weight%) of the core portion is within the range of 65 to 90.
In Article 1, The above shell portion comprises a fifth unit of alkyl acrylate, a sixth unit of alkyl methacrylate, a seventh unit of styrene-based monomer, and an eighth unit of a monomer containing a polar functional group, forming a battery separator binder composition.
In Article 6, A battery separator binder composition in which the fifth unit content (weight%) of the shell portion is within the range of 50 to 90.
In Article 1, The above solvent is a battery separator binder composition comprising an aqueous solvent.
In Article 1, Battery separator binder composition further comprising inorganic particles.
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 glass transition temperature (°C) of the above polymer particles is in the range of 25 to 50, and The electrolyte gel content (weight%) of the above polymer particles is in the range of 70 to 90, and The glass transition temperature (°C) of the above core part is in the range of 70 to 99, and A battery separator in which the electrolyte gel content (weight%) of the core portion is within the range of 90 to 100.
In Article 10, The above outer layer is a battery separator comprising a dried product of the battery separator binder composition.
In Article 10, The above outer layer is a battery separator further comprising inorganic particles.
In Article 12, It further includes 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.
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 glass transition temperature (°C) of the above polymer particles is in the range of 25 to 50, and The electrolyte gel content (weight%) of the above polymer particles is in the range of 70 to 90, and The glass transition temperature (°C) of the above core part is in the range of 70 to 99, and A battery in which the electrolyte gel content (weight%) of the core portion is within the range of 90 to 100.
In Article 14, 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. 10-2024-0154695 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 electrolyte impregnation of Example 1. Figure 2 is an SEM image of Comparative Example 1 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 polymer particles having a core-shell structure. The polymer particles having a core-shell structure may include a core portion and a shell portion. The present invention can control the characteristics of the polymer particles. As a result, the battery separator binder composition of the present invention can reduce the phenomenon of becoming a film due to heat and pressure, or even if it becomes a film, it can return to a particle form upon electrolyte impregnation. The glass transition temperature (°C) of the polymer particles is within the range of 25 to 50. The glass transition temperature of the polymer particles can affect