Intermediate Layer Adhesion for Battery Separator Peeling

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Solution Overview

Problem

Non-aqueous electrolyte secondary batteries with enlarged areas tend to distort under external forces, leading to deviation or peeling between the cathode and separator, or between the anode and separator, which compromises capacity retention.

Innovation Solution

An intermediate layer formed from aqueous latex with polymer particles containing a copolymer derived from unsaturated dibasic acid, unsaturated dibasic acid monoester, and vinylidene fluoride-based monomers is used to enhance adhesion between the cathode, anode, and separator, ensuring strong adherence and improved adhesive strength.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If the battery area is enlarged to achieve larger capacity, then the battery capacity increases, but the laminate becomes prone to distortion and peeling under external forces

Engineering Contradiction:
Improvebattery capacityVSAvoidadhesion between cathode, anode and separator
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

An intermediate layer comprising a fluororesin binder and inorganic filler is introduced between the electrodes and separator. This intermediate layer acts as a mediator that enhances adhesion, prevents peeling, and maintains structural integrity of the enlarged battery laminate under external forces while preserving the increased capacity

Inventive Principle:
Principle #24Intermediary (Mediator)

2Quantity of substance

If the battery area is enlarged to achieve larger capacity, then the battery capacity increases, but distortion occurs under external forces

Engineering Contradiction:
Improvebattery capacityVSAvoidstructural stability of laminate
Core Design Contradiction:
Quantity of substanceVSStability of the object's composition

Solution Approach 1:

The intermediate layer is formulated as a composite material combining fluororesin binder with inorganic filler particles. This composite structure provides both flexibility to accommodate size and rigidity to resist distortion, enabling the enlarged battery to maintain structural stability under external forces while achieving larger capacity

Inventive Principle:
Principle #40Composite materials

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 effectively maintains long capacity retention and enlarged area performance of non-aqueous electrolyte secondary batteries by preventing distortion and peeling, ensuring reliable battery performance.

Implementation Method 1

an intermediate layer formed from an aqueous latex, the aqueous latex comprising polymer particles dispersed in water, the polymer particles containing a copolymer comprising a structural unit derived from an unsaturated dibasic acid, and/or a structural unit derived from an unsaturated dibasic acid monoester, and a structural unit derived from a vinylidene fluoride-based monomer

Methodology Applied
Scientific EffectAdhesion: Adhesive

Data Source

PatentEP3196959B1Intermediate layer, separator/intermediate layer laminate, and structure for nonaqueous electrolyte secondary batteries
Publication Date: 2020.05.13 KUREHA CORPORATION
  • EP3196959B1 patent drawingFigure 1
  • EP3196959B1 patent drawingFigure 2
  • EP3196959B1 patent drawingFigure 3

AI summary

Provided are a structure for non-aqueous electrolyte secondary batteries in which at least one of a cathode with a separator and an anode with a separator are strongly adhered, an aqueous latex used to obtain the structure for non-aqueous electrolyte secondary batteries, and a separator/intermediate layer laminate. The aqueous latex according to the present invention contains polymer particles dispersed in water, the polymer particles containing a copolymer comprising a structural unit derived from an unsaturated dibasic acid, and/or a structural unit derived from an unsaturated dibasic acid monoester, and a structural unit derived from a vinylidene fluoride-based monomer, the aqueous latex being used in production of an intermediate layer to be provided in a structure for non-aqueous electrolyte secondary batteries having a cathode, an anode, and a separator laminated between the cathode and the anode, the intermediate layer being provided in at least one of between the cathode and the separator and between the anode and the separator.