Porous Battery Separator Balancing Ion Flow and Low Moisture

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Solution Overview

Problem

Conventional separators for electrochemical devices face challenges in achieving both high ion permeability and low moisture content, which is essential to prevent gas generation in batteries.

Innovation Solution

A separator with a porous layer containing two or more nitrogen-containing aromatic resins and a filler content of not less than 0% by weight and less than 20% by weight, which allows for high ion permeability without excessive moisture retention.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If inorganic particles are used as filler to make the heat-resistant layer porous for ensuring ion permeability, then ion permeability is improved, but moisture content in the heat-resistant layer increases

Engineering Contradiction:
Improveion permeabilityVSAvoidmoisture content
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The patent uses porous inorganic particles (such as alumina, silica, or boehmite) as filler in the heat-resistant layer. These particles create a porous structure that ensures high ion permeability while the controlled filler content (not less than 0% by weight and not more than 20% by weight) prevents excessive moisture absorption, thus resolving the contradiction between ion permeability and moisture content

Inventive Principle:
Principle #31Porous materials

Solution Approach 2:

The patent optimizes the filler content parameter within a specific range (0-20% by weight) to balance ion permeability and moisture content. By controlling this parameter, the heat-resistant layer achieves sufficient porosity for ion transport while limiting the total filler quantity that could otherwise increase moisture absorption

Inventive Principle:
Principle #35Parameter changes

2Reliability

If filler content is increased to ensure ion permeability, then ion permeability is improved, but gas generation in the battery increases due to higher moisture content

Engineering Contradiction:
Improveion permeabilityVSAvoidgas generation
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent employs porous inorganic particles as filler to create a heat-resistant layer with optimized porosity. This structure provides adequate ion permeability pathways while the controlled filler content (≤20% by weight) prevents excessive moisture retention that would lead to gas generation, thus eliminating the harmful effect

Inventive Principle:
Principle #31Porous materials

Solution Approach 2:

The patent converts the potential harm of filler-induced moisture absorption into a benefit by carefully selecting and controlling the filler content within 0-20% by weight. This optimized filler usage provides necessary porosity for ion transport while minimizing moisture-related gas generation, turning a potential problem into a solution

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 proposed separator effectively achieves both high ion permeability and low moisture content, thereby reducing gas generation in batteries and improving their performance and safety.

Implementation Method 1

a porous layer that contains two or more nitrogen-containing aromatic resins and that has a filler content of not less than 0% by weight and less than 20% by weight

Methodology Applied
Scientific EffectIon permeability: Permeation

Data Source

PatentUS20250202048A1Separator for electrochemical device, material and electrochemical device
Publication Date: 2025.06.19 SSLM

AI summary

Provided is a separator for an electrochemical device which separator achieves both high ion permeability and a low moisture content. The separator of the present disclosure includes a porous layer that contains two or more nitrogen-containing aromatic resins and that has a filler content of not less than 0% by weight and less than 20% by weight.