Modified Separator for Secondary Battery Storage Stability

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Solution Overview

Problem

Lithium ion batteries face challenges in maintaining stability and long-term storage characteristics, especially at high temperatures, due to the use of organic/inorganic composite films which can lead to increased resistance and side reactions with moisture, affecting their performance in applications like electric vehicles.

Innovation Solution

A modified organic/inorganic composite film separator is developed with an inorganic layer formed by coating a slurry of inorganic particles and a modifying agent on an organic film, converting active sites into non-reactive sites to inhibit moisture-related side reactions, enhancing electrical and thermal stability and wettability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an organic/inorganic composite film separator is used to improve electrical and thermal stability, then wettability and thermoelectric stability are improved, but long-term storage characteristics deteriorate due to increased resistance

Engineering Contradiction:
Improveelectrical and thermal stabilityVSAvoidlong-term storage characteristics
Core Design Contradiction:
ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The patent applies parameter changes by modifying the inorganic particles through surface treatment with silane coupling agents or other coatings, altering their surface properties to reduce moisture adsorption while maintaining the beneficial electrical and thermal stability of the organic/inorganic composite film separator

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces an intermediary layer or surface treatment on the inorganic particles that acts as a barrier between moisture and the inorganic material, preventing harmful interactions while allowing the separator to maintain its structural and functional properties

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If an inorganic layer is coated on the separator to improve wettability and stability, then electrical stability improves, but resistance increases during storage particularly at high temperatures

Engineering Contradiction:
Improveelectrical stabilityVSAvoidresistance increase during storage
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent modifies the surface parameters of the inorganic layer through chemical treatment or coating with hydrophobic materials, changing its interaction with moisture to prevent resistance increase during storage while preserving electrical stability during operation

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite structure where the inorganic particles are combined with organic modifiers or surface treatments, forming a multi-component system that exhibits both electrical stability and resistance to moisture-induced resistance increase

Inventive Principle:
Principle #40Composite materials

3Temperature

If inorganic particles are used in the separator to improve thermal stability, then battery stability improves, but side reactions with moisture occur leading to performance deterioration

Engineering Contradiction:
Improvethermal stabilityVSAvoidside reactions with moisture
Core Design Contradiction:
TemperatureVSObject-generated harmful factors

Solution Approach 1:

The patent introduces a protective intermediary layer on the inorganic particles that prevents direct contact between moisture and the inorganic material, eliminating side reactions while maintaining thermal stability through the inorganic component's inherent properties

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent converts the potentially harmful hydrophilic nature of inorganic particles into a benefit by applying hydrophobic surface treatments, transforming the material's interaction with moisture from harmful to beneficial or neutral

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

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 modified separator improves the battery's high-temperature storage characteristics and overall stability, reducing resistance increase and maintaining performance over long-term storage, making it suitable for high-power output applications.

Implementation Method 1

the inorganic layer has a structure with modification of active sites of inorganic particles into non-reactive sites... which results in strong chemical adsorption of moisture

Methodology Applied
Scientific EffectAdsorption: Adsorption

Implementation Method 2

the separator not only serves to electrically isolate the cathode and the anode from each other, but also plays an important role... facilitates ionic migration... serves as a passage through which lithium ions migrate between the anode and the cathode

Methodology Applied
Scientific EffectIonic migration: Conduction (electrical)

Implementation Method 3

Provision of the organic/inorganic composite film using an inorganic material in a coat of the separator increases wettability of the electrolyte

Methodology Applied
Scientific EffectWettability: Wetting

Data Source

PatentEP2642557B1Secondary battery with improved storage characteristics and method for manufacturing the same
Publication Date: 2014.10.01 LG CHEM LTD

AI summary

Provided is a secondary battery comprising a separator having an inorganic layer wherein active sites of inorganic particles in the inorganic layer are modified into non-reactive sites. Use of the separator leads to improvements in wettability of an electrolyte and thermoelectric stability and storage characteristics of the secondary battery. Provided is also a method of manufacturing the same secondary battery.