Battery Separator Coating With Hollow Adhesive Particles

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Solution Overview

Problem

Conventional secondary battery separators with electrode-separator combinations suffer from weak binding forces, leading to separation issues, poor productivity in manufacturing, and degraded battery performance due to inadequate adhesive strength and electrolyte elution.

Innovation Solution

A separator with a coating layer containing inorganic particles and hollow adhesive particles is applied to both surfaces of a porous substrate, allowing the hollow adhesive particles to float and form an adhesive layer without a separate adhesive application process, enhancing adhesive strength while minimizing electrolyte elution and swelling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a polymer resin layer is separately formed on an inorganic particle layer to improve adhesive strength, then adhesive strength is improved, but manufacturing time increases and process efficiency decreases

Engineering Contradiction:
Improveadhesive strengthVSAvoidmanufacturing time
Core Design Contradiction:
StrengthVSLoss of time

Solution Approach 1:

The patent combines the inorganic particle layer and polymer resin layer into a single coating layer formed by one application process. The coating composition contains both inorganic particles and polymer resin particles mixed together, which are applied simultaneously to the porous substrate and then dried to form an integrated coating layer, eliminating the need for separate formation processes.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The single coating layer serves multiple functions: it provides adhesive strength through polymer resin particles, maintains thermal stability through inorganic particles, and enables improved productivity by combining multiple functions into one application process rather than requiring separate processes for each function.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Ease of manufacture

If polymer resin and inorganic particles are mixed to form a one-component coating layer to simplify the manufacturing process, then process complexity is reduced, but adhesive strength becomes poor

Engineering Contradiction:
Improveprocess simplicityVSAvoidadhesive strength
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The patent creates local quality differentiation within the coating layer by controlling the distribution of polymer resin particles and inorganic particles. The coating composition is designed so that polymer resin particles are distributed throughout the coating layer, with some concentration near the surface, while inorganic particles provide structural support. This local distribution ensures that adhesive function is concentrated where needed while maintaining overall coating integrity.

Inventive Principle:
Principle #3Local quality

3Strength

If a large amount of polymer resin is added to improve adhesive performance, then adhesive strength is improved, but battery performance degrades due to polymer resin dissolving and eluting into electrolyte

Engineering Contradiction:
Improveadhesive strengthVSAvoidbattery performance
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent creates a composite coating layer combining polymer resin particles and inorganic particles in specific proportions. The inorganic particles serve as a matrix or support structure that limits the contact between polymer resin and electrolyte, while the polymer resin provides adhesive function. This composite structure allows achieving adequate adhesive strength with reduced polymer resin content, preventing excessive elution and swelling that would degrade battery performance.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent optimizes the composition parameters of the coating layer by controlling the weight ratio of polymer resin to inorganic particles, the particle size distribution, and the coating thickness. By adjusting these parameters, the adhesive strength is maximized while minimizing the amount of polymer resin that can dissolve or swell in the electrolyte, thus maintaining battery performance.

Inventive Principle:
Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The solution provides improved adhesive strength between the electrode and separator, allowing for higher capacity and larger battery sizes with reduced manufacturing time and electrolyte-related issues, maintaining alignment and preventing separation during charge/discharge cycles.

Implementation Method 1

the hollow adhesive particles having a lower specific gravity than the inorganic particles float to form an adhesive layer

Methodology Applied
Scientific EffectBuoyancy: Archimedes' Principle (Buoyancy)

Data Source

PatentEP4459776A1Separator, method for manufacturing the same, and secondary battery including the same
Publication Date: 2024.11.06 SK INNOVATION CO LTD
  • EP4459776A1 patent drawingFigure 1~2
  • EP4459776A1 patent drawingFigure 3~4
  • EP4459776A1 patent drawing

AI summary

Provided are a separator, a method for manufacturing the same, and a secondary battery including the same. Specifically, a separator including hollow adhesive particles, a method for manufacturing the same, and a secondary battery including the same are provided. The separator according to an exemplary embodiment of the present disclosure includes: a porous substrate; and at least one coating layer which is placed on one or both surfaces of the porous substrate and includes inorganic particles and hollow adhesive particles. The separator of the present disclosure has improved surface adhesive strength, so that it may be adhered to an electrode with high adhesive strength. The present invention further provides a method for manufacturing a secondary battery including the separator. Further provided is a use of the hollow adhesive particles to increase adhesion to a porous separator substrate, and/or to suppress swelling of a separator in a secondary battery.