Porous Ceramic Separator Slurry for Thin Stable Battery Layers

Solution Overview

Problem

Conventional battery separators face challenges such as reduced mechanical integrity, thermal instability, and increased thickness, which can lead to electrical shorting and reduced ionic transport rates, especially in ceramic separators used in energy storage devices.

Innovation Solution

The development of a battery cell component with a ceramic layer produced by admixing ceramic materials with a water-soluble dispersant and an organic polymeric binder, forming a slurry with a viscosity below 200 cp, and depositing it on a substrate to a thickness of less than 10 μm, along with an adhesive material, to create a multi-layer separator with improved mechanical and thermal stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the separator thickness is reduced to improve volumetric density, then the mechanical integrity and thermal stability deteriorate

Engineering Contradiction:

Improvevolumetric densityVSAvoidmechanical integrity

Core Design Contradiction:

Volume of moving objectVSStrength

Solution Approach 1:

The patent employs a composite separator structure consisting of a porous polymer matrix embedded with ceramic particles (such as alumina, silica, or boehmite). This composite architecture combines the flexibility and processability of polymers with the thermal stability and mechanical strength of ceramics, enabling thin separator designs that maintain structural integrity. The ceramic particles act as reinforcing fillers that prevent polymer chain collapse and maintain porosity even at reduced thicknesses of 15 μm or less.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The separator design incorporates localized regions with different properties: the bulk polymer matrix provides flexibility and ion transport channels, while distributed ceramic particles provide localized thermal stability and mechanical reinforcement. The ceramic particle concentration and distribution are optimized to provide strength exactly where needed without compromising overall porosity or ionic conductivity.

Inventive Principle:

Principle #3Local quality

2Volume of moving object

If the separator thickness is reduced to improve volumetric density, then the ionic transport rate deteriorates

Engineering Contradiction:

Improvevolumetric densityVSAvoidionic transport rate

Core Design Contradiction:

Volume of moving objectVSSpeed

Solution Approach 1:

The separator utilizes a highly porous polymer matrix with controlled pore sizes and distributions that facilitate rapid ion transport. The porosity is maintained at optimal levels (30-80%) despite reduced thickness by incorporating hydrophilic ceramic particles that prevent pore collapse and maintain open channels for ion flow. The pore structure is engineered to provide tortuosity-optimized pathways that enable high ionic conductivity even in thin separators.

Inventive Principle:

Principle #31Porous materials

3Device complexity

If conventional separator materials are used to maintain simplicity, then the thermal stability and mechanical integrity deteriorate under stress

Engineering Contradiction:

Improveseparator structureVSAvoidthermal stability

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent employs a composite separator structure consisting of a porous polymer matrix embedded with ceramic particles (such as alumina, silica, or boehmite). This composite architecture combines the flexibility and processability of polymers with the thermal stability and mechanical strength of ceramics, enabling thin separator designs that maintain structural integrity. The ceramic particles act as reinforcing fillers that prevent polymer chain collapse and maintain porosity even at reduced thicknesses of 15 μm or less.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The separator design incorporates localized regions with different properties: the bulk polymer matrix provides flexibility and ion transport channels, while distributed ceramic particles provide localized thermal stability and mechanical reinforcement. The ceramic particle concentration and distribution are optimized to provide strength exactly where needed without compromising overall porosity or ionic conductivity.

Inventive Principle:

Principle #35Parameter changes

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 approach results in battery separators with enhanced mechanical integrity, reduced thickness, and improved thermal stability, allowing for better handling and ionic transport, while maintaining porosity and air permeability, thus addressing the limitations of conventional designs.

Implementation Method 1

admixing a ceramic with a water-soluble dispersant to form a first mixture. The methods may include admixing an organic polymeric dispersant with the first mixture to form a second mixture

Methodology Applied

Scientific EffectSurface tension reduction: Surfactant

Implementation Method 2

depositing the slurry on a substrate. The slurry may be deposited on the substrate to a thickness of less than or about 10 μm

Methodology Applied

Scientific EffectCapillary action: Capillary Action

Implementation Method 3

The methods may include admixing a binder with the second mixture to form a slurry

Methodology Applied

Scientific EffectEvaporation: Evaporation

Data Source

PatentUS11870037B2Porous ceramic separator materials and formation processes

Publication Date: 2024.01.09 APPLE INC

AI summary

Energy storage devices, battery cells, and batteries may include a battery cell component that may be or include a ceramic layer produced by methods including admixing a ceramic with a water-soluble dispersant to form a first mixture. The methods may include admixing an organic polymeric dispersant with the first mixture to form a second mixture. The methods may include admixing a binder with the second mixture to form a slurry. The methods may also include depositing the slurry on a substrate.