Battery Separator Coating to Reduce High-Temperature Gas Emission

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Solution Overview

Problem

Lithium secondary batteries face risks of fire and explosion due to increased capacity, particularly at high temperatures, caused by gas generation from electrolyte decomposition, leading to reduced lifespan and performance.

Innovation Solution

A separator with a porous substrate and a coating layer comprising a nitrogen-containing water-soluble polymer and barium sulfate particles is developed, which reduces gas emission and enhances high-temperature storage characteristics and battery life.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If the capacity of lithium secondary batteries is increased for electric vehicles and energy storage devices, then the energy storage capability is improved, but the risk of fire and explosion increases due to gas generation from electrolyte decomposition at high temperatures

Engineering Contradiction:

Improvebattery capacityVSAvoidfire and explosion risk

Core Design Contradiction:

Quantity of substanceVSObject-affected harmful factors

Solution Approach 1:

The patent converts the harmful effect of gas generation into a beneficial outcome by incorporating barium sulfate particles in the coating layer that catalyze the decomposition of decomposed electrolyte, transforming harmful gases into harmless substances and thereby reducing fire and explosion risks while maintaining high battery capacity

Inventive Principle:

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

Solution Approach 2:

The patent uses a composite coating layer comprising a nitrogen-containing water-soluble polymer and barium sulfate particles applied on the porous substrate. This composite structure combines the protective properties of the polymer with the catalytic decomposition capabilities of barium sulfate, effectively mitigating fire and explosion risks without compromising battery capacity

Inventive Principle:

Principle #40Composite materials

2Reliability

If a coating layer is applied on the porous substrate to reduce gas emission, then the safety and high-temperature storage characteristics are improved, but the manufacturing complexity increases

Engineering Contradiction:

Improvehigh-temperature storage characteristicsVSAvoidseparator structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent employs a porous substrate as the base structure of the separator, which maintains ion permeability while providing a framework for the coating layer. The porous structure allows the coating to be applied effectively without significantly increasing manufacturing complexity, as porous materials are well-established in battery separator production

Inventive Principle:

Principle #31Porous materials

Solution Approach 2:

The patent specifies particular parameters for the coating layer components, such as the nitrogen-containing water-soluble polymer and barium sulfate particles with controlled particle sizes (e.g., 100-500 nm). By optimizing these parameters, the coating layer achieves effective gas emission reduction and improved high-temperature storage characteristics while maintaining manufacturability through standardized material specifications

Inventive Principle:

Principle #35Parameter changes

3Duration of action of stationary object

If barium sulfate particles are used in the coating layer to decrease gas emission, then the battery life and safety are improved, but the manufacturing precision requirements increase

Engineering Contradiction:

Improvebattery lifeVSAvoidcoating layer composition

Core Design Contradiction:

Duration of action of stationary objectVSManufacturing precision

Solution Approach 1:

The patent incorporates barium sulfate particles at a specific concentration range (e.g., 1-10 wt%) in the coating layer, which is sufficient to catalyze the decomposition of electrolyte and reduce gas emission without requiring excessive precision in manufacturing. This partial action approach achieves the desired battery life extension and safety improvement while keeping manufacturing requirements manageable

Inventive Principle:

Principle #16Partial or excessive 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

The separator significantly decreases gas emission and improves high-temperature storage stability and long-term life of lithium secondary batteries, addressing safety concerns and performance degradation.

Implementation Method 1

it has been found that gas emission may be decreased by using a separator comprising a porous substrate and a coating layer formed on one or both surfaces of the porous substrate, wherein the coating layer comprises a binder and barium sulfate particles

Methodology Applied

Scientific EffectCatalysis: Catalysis

Implementation Method 2

the coating layer comprises a nitrogen-containing water-soluble polymer and barium sulfate particles

Methodology Applied

Scientific EffectAdsorption: Adsorption

Data Source

PatentUS20250105461A1Separator and lithium secondary battery comprising the same

Publication Date: 2025.03.27 SK INNOVATION CO LTD

AI summary

Separators and lithium secondary batteries including the separators that can exhibit excellent high-temperature storage stability and capacity retention rate of a lithium secondary battery, a low resistance increase rate, and significantly decreased gas emission are disclosed. In an example embodiment, a separator includes: a porous substrate and a coating layer formed on one or both surfaces of the porous substrate, wherein the coating layer includes a water-soluble crosslinked polyacrylamide-based binder and barium sulfate.