Secondary Battery Gel Electrolyte Curing for Low-Resistance Adhesion

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Solution Overview

Problem

Existing secondary battery manufacturing methods face challenges in reducing resistance while maintaining cell stiffness and mechanical durability, particularly due to excessive binder usage in separators and pre-gelation issues with liquid electrolytes.

Innovation Solution

A method for manufacturing a secondary battery involving an electrode assembly with a separator having ceramic coating layers with a controlled binder content and a gel polymer electrolyte composition without a polymerization initiator, where the adhesive composition includes a polymerization initiator that dissolves and cures the electrolyte upon injection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the binder content in the ceramic coating layers is increased to improve adhesion between electrode and separator, then adhesion is improved, but resistance increases and energy density decreases

Engineering Contradiction:

Improveadhesion between electrode and separatorVSAvoidresistance

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The patent optimizes the binder content parameter to a specific range (0.1-5 wt%) to achieve the optimal balance between adhesion and resistance. This parameter change resolves the contradiction by finding the precise value that satisfies both requirements simultaneously.

Inventive Principle:

Principle #35Parameter changes

2Strength

If the binder content in the ceramic coating layers is increased to improve adhesion, then adhesion is improved, but energy density decreases due to increased separator thickness

Engineering Contradiction:

Improveadhesion between electrode and separatorVSAvoidenergy density

Core Design Contradiction:

StrengthVSQuantity of substance

Solution Approach 1:

The patent optimizes the binder content parameter to a specific range (0.1-5 wt%) to achieve the optimal balance between adhesion and energy density. This parameter change resolves the contradiction by finding the precise value that satisfies both requirements simultaneously.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If a liquid electrolyte is used to achieve good ionic conductivity, then ionic conductivity is improved, but cell stiffness decreases and leakage risk increases

Engineering Contradiction:

Improveionic conductivityVSAvoidcell stiffness

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The patent uses a gel polymer electrolyte that combines the ionic conductivity of liquid electrolytes with the mechanical strength and non-leaking properties of solid polymers. This composite material approach resolves the contradiction by integrating the beneficial properties of both material types.

Inventive Principle:

Principle #40Composite materials

4Strength

If a gel polymer electrolyte is used to improve cell stiffness and prevent leakage, then cell stiffness is improved, but interfacial resistance increases and ionic conductivity decreases

Engineering Contradiction:

Improvecell stiffnessVSAvoidionic conductivity

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

Inventive Principle:

Principle #40Composite materials

5Ease of manufacture

If the oligomer compound is pre-gelled by the polymerization initiator before injection, then the gel polymer electrolyte composition is prepared in advance, but ion conductivity deteriorates and resistance increases due to insufficient impregnation

Engineering Contradiction:

Improvepreparation convenienceVSAvoidion conductivity

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent performs preliminary actions (mixing oligomer, lithium salt, and solvent) while deliberately excluding the polymerization initiator until the injection step. This controlled preliminary action allows proper impregnation before gelation occurs, resolving the contradiction between preparation convenience and ion conductivity.

Inventive Principle:

Principle #10Preliminary action

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

This method effectively reduces resistance, enhances cell stiffness, and improves mechanical durability by preventing excessive binder-related issues and pre-gelation, resulting in improved performance and longevity of the secondary battery.

Implementation Method 1

the adhesive and the polymerization initiator are dissolved by the injection of the gel polymer electrolyte composition

Methodology Applied

Scientific EffectDissolution: Solvation

Implementation Method 2

the gel polymer electrolyte composition is cured by the dissolved polymerization initiator

Methodology Applied

Scientific EffectPolymerization: Photopolymerisation

Data Source

PatentUS20250062416A1Method for Manufacturing Secondary Battery

Publication Date: 2025.02.20 LG ENERGY SOLUTION LTD

AI summary

A method for manufacturing a secondary battery, includes preparing an electrode assembly in which electrodes and a separator are alternately laminated, and an adhesive composition is applied to the surface of at least one of the electrodes or the separator, thereby allowing the electrodes and the separator to adhere to each other; accommodating the electrode assembly in a battery case; injecting a gel polymer electrolyte composition into the battery case to impregnate the electrode assembly with the gel polymer electrolyte composition; curing the gel polymer electrolyte composition; and sealing the battery case, wherein the separator includes a porous substrate and ceramic coating layers disposed on both surfaces of the porous substrate.