Glass Composite Battery Separator for Heat-Stable Electrolyte Wetting

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Solution Overview

Problem

Existing battery separators face challenges with mechanical stability at high temperatures, significant shrinkage, poor wetting with electrolytes, and limited participation in electrode reactions, which affect their performance and longevity.

Innovation Solution

A battery separator composite comprising 5-95% glass fibers, 5-95% glass plates with specific compositions, and 0-95% binder, offering enhanced temperature stability, mechanical flexibility, and improved electrolyte wetting, allowing ion participation in electrode processes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If polymer-based separators are used, then mechanical stability is achieved at low temperatures, but temperature stability deteriorates above 100°C with significant shrinkage

Engineering Contradiction:
Improvemechanical stabilityVSAvoidtemperature stability
Core Design Contradiction:
StrengthVSTemperature

Solution Approach 1:

The patent employs a composite structure combining polymer matrix with glass fiber reinforcements and ceramic coatings. This composite approach allows the separator to maintain mechanical flexibility from the polymer while gaining high-temperature stability from the glass and ceramic components that resist shrinkage and deformation at elevated temperatures.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent modifies the chemical composition parameters of the separator by incorporating specific ratios of glass fibers (5-50 wt%) and ceramic particles (1-20 wt%) into the polymer matrix. These compositional changes enable the material to maintain structural integrity across a broader temperature range while preserving low-temperature mechanical properties.

Inventive Principle:
Principle #35Parameter changes

2Ease of manufacture

If polymer-based separators are used, then ease of manufacture is achieved, but wetting with electrolyte liquid deteriorates

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidelectrolyte wetting
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent utilizes a porous structure with controlled pore size distribution (0.01-10 μm) created through phase separation or foam formation during manufacturing. This porous architecture increases the surface area available for electrolyte contact and capillary action, significantly improving wetting performance while maintaining compatibility with standard polymer processing techniques.

Inventive Principle:
Principle #31Porous materials

3Temperature

If glass-based separators are used, then temperature stability is improved, but mechanical flexibility deteriorates

Engineering Contradiction:
Improvetemperature stabilityVSAvoidmechanical flexibility
Core Design Contradiction:
TemperatureVSStrength

Solution Approach 1:

The patent applies glass fiber reinforcements and ceramic coatings locally within the polymer matrix rather than using bulk glass materials. This localized approach provides high-temperature stability at specific critical regions while allowing the polymer matrix to maintain overall flexibility and mechanical compliance in other areas.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent uses thin glass fiber mats and flexible ceramic-coated structures embedded in the polymer matrix. These thin-film reinforcements provide thermal stability without creating rigid, brittle structures, maintaining the separator's flexibility needed for battery assembly and operation.

Inventive Principle:
Principle #30Flexible shells and thin films

4Temperature

If ceramic-based separators are used, then temperature stability is improved, but weight increases

Engineering Contradiction:
Improvetemperature stabilityVSAvoidseparator weight
Core Design Contradiction:
TemperatureVSWeight of moving object

Solution Approach 1:

The patent employs porous ceramic coatings and hollow glass microsphere reinforcements that provide high-temperature stability with minimal material volume. The porous structure reduces the density of the ceramic components while maintaining their thermal resistance properties, thereby limiting weight increase.

Inventive Principle:
Principle #31Porous materials

Solution Approach 2:

The patent creates a hybrid composite where lightweight polymer matrix is combined with small quantities of high-performance ceramic and glass components. This composite strategy achieves the required temperature stability using minimal amounts of heavy ceramic material, keeping the overall separator weight low compared to fully ceramic alternatives.

Inventive Principle:
Principle #40Composite 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 solution provides high temperature stability, reduced shrinkage, optimized electrolyte wetting, and enhanced cell performance through ion participation, leading to improved battery performance and extended lifespan.

Implementation Method 1

the glass platelets (B) have an average thickness of 0.05 μm to 30 μm... the battery separator has a porosity in the range of 10 to 70% and a total thickness of 0.01 mm to 0.5 mm

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 2

a porous, ion-permeable glass disk or a porous, ion-permeable glass ceramic disk, the disk having an average pore size of less than 1 μm

Methodology Applied
Scientific EffectDiffusion: Diffusion

Implementation Method 3

the glass platelets (B) have the following composition: 45 to 55% by weight of SiO2, 38 to 45% by weight of B2O3, 5 to 9% by weight of Na2O... 5 to 9 wt.% Li2O

Methodology Applied
Scientific EffectIon exchange: Ion Exchange

Implementation Method 4

a composite that contains the following components: (A) 5 to 95% by weight of at least one carrier material consisting of glass fibers... (C) 0 to 95% by weight of at least one binder

Methodology Applied
Scientific EffectAdhesion: Adhesive

Data Source

PatentEP3607597B1Glass-based battery separator
Publication Date: 2023.12.13 VITRULAN TEXTILE GLASS GMBH
  • EP3607597B1 patent drawingFigure 1~2
  • EP3607597B1 patent drawingFigure 3~4c
  • EP3607597B1 patent drawingFigure 5~6

AI summary

The present invention relates to a battery separator containing a composite that in turn contains the following components: (A) 5 to 95 wt.-% of at least one carrier material that consists of glass fibers, the carrier material being selected from the group comprising nonwovens, laid scrims, knitted fabrics, woven fabrics and/or mixtures thereof; (B) 5 to 95 wt.-% of at least one glass platelet having an average thickness of 0.05 μm to 30 μm; and (C) 0 to 95 wt.-% of at least one binder; the components (A), (B) and (C) adding up to 100 wt.-% and the battery separator having a porosity in the range of 10 to 70% and a total thickness of 0.01 mm to 0.5 mm. The present invention further relates to methods for producing the battery separator and to the use thereof in a battery.