Composition for electrochemical element functional layer, composition precursor for electrochemical element functional layer, electrochemical element functional layer, laminate for electrochemical element, and electrochemical element

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Solution Overview

Problem

Conventional electrochemical devices such as lithium secondary batteries face issues with metal deposition on electrodes during charging and discharging, insufficient inhibition of short circuiting, and swelling, as well as inadequate wet adhesiveness of functional layers in electrolyte solutions.

Innovation Solution

A composition for an electrochemical device functional layer containing a particulate polymer with a hydroxy group-substituted aromatic ring-containing structural unit, which can be derived from a monomer with an alkoxy group-substituted aromatic ring-containing monomer unit, is used to form a functional layer with enhanced wet adhesiveness and inhibit metal deposition and swelling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a conventional electrolyte-swellable resin layer (urethane resin) is formed on a separator substrate, then heat resistance and strength are improved, but wet adhesiveness in electrolyte solution is insufficient and metal deposition cannot be effectively inhibited

Engineering Contradiction:

Improvestrength of functional layerVSAvoidwet adhesiveness and inhibition of metal deposition

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The patent uses a composite polymer comprising polyacrylic acid and polyacrylonitrile in specific weight ratios (polyacrylic acid: 30-70 wt%, polyacrylonitrile: 30-70 wt%). This composite material combines the electrochemical stability and mechanical strength of polyacrylonitrile with the metal ion coordination ability of polyacrylic acid, achieving both structural integrity and effective metal deposition inhibition while maintaining excellent wet adhesiveness in electrolyte solution.

Inventive Principle:

Principle #40Composite materials

2Reliability

If the functional layer is made more adhesive to improve wet adhesiveness, then adhesion to electrode substrates improves, but swelling of the electrochemical device increases

Engineering Contradiction:

Improvewet adhesivenessVSAvoidswelling of electrochemical device

Core Design Contradiction:

ReliabilityVSVolume of stationary object

Solution Approach 1:

The patent precisely controls the weight ratio parameters of polyacrylic acid and polyacrylonitrile (both components at 30-70 wt%, with their sum being 60-140 wt%). This parameter optimization ensures the functional layer has sufficient wet adhesiveness while limiting excessive swelling during charging-discharging cycles, as the balanced composition provides both adhesive functionality and dimensional stability.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If a thicker functional layer is used to improve inhibition of metal deposition, then metal deposition resistance improves, but internal resistance of the battery increases

Engineering Contradiction:

Improveinhibition of metal depositionVSAvoidinternal resistance

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The functional layer is formed with a porous structure that allows efficient ion transport while providing sufficient thickness for metal deposition inhibition. The porous architecture reduces the effective diffusion path for metal ions and maintains low internal resistance by facilitating electrolyte penetration and ion flow, even when the layer has adequate thickness for preventing metal deposition.

Inventive Principle:

Principle #31Porous 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 functional layer exhibits excellent wet adhesiveness and effectively inhibits metal deposition and swelling, improving the performance and stability of electrochemical devices.

Implementation Method 1

a functional layer that has excellent wet adhesiveness

Methodology Applied

Scientific EffectAdhesion: Adhesive

Implementation Method 2

swelling of the electrochemical device in accompaniment to charging and discharging cannot be sufficiently inhibited

Methodology Applied

Scientific EffectAbsorption: Absorption (physical)

Data Source

PatentEP4614712A1Composition for electrochemical element functional layer, composition precursor for electrochemical element functional layer, electrochemical element functional layer, laminate for electrochemical element, and electrochemical element

Publication Date: 2025.09.10 ZEON CORP

AI summary

Provided is a composition for an electrochemical device functional layer with which it is possible to form a functional layer that has excellent wet adhesiveness and that is capable of good inhibition of metal deposition on an electrode during charging and discharging and swelling of an electrochemical device. The composition for an electrochemical device functional layer contains a particulate polymer including a structural unit that includes a group having an aromatic ring where at least one hydrogen atom is substituted with a hydroxy group.