Ceramic Separator Dual Binder System for Battery Stability
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Solution Overview
Problem
Ceramic separators in lithium batteries face challenges with thermal and mechanical stability, adhesion to substrates, and ion conductivity due to limitations in binder systems and ceramic particle distribution, leading to potential overheating, micro-shorts, and compromised battery performance.
Innovation Solution
A ceramic separator using a dual binder system comprising a linear polymer and a cross-linking polymer, which enhances adhesion and heat tolerance, allowing for a higher percentage of ceramic particulates and optimized hole distribution for improved ion conductivity and electrical insulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If ceramic particles are used as main material to replace polyolefin, then thermal stability is improved, but electrical insulation is compromised due to particle rearrangement and adhesive entanglement creating holes
Solution Approach 1:
The invention uses a composite structure combining ceramic particles with a dual-polymer adhesive system (reactive polymer + linear polymer). This composite approach allows the ceramic particles to provide thermal stability while the polymer matrix maintains electrical insulation by filling gaps and preventing conductive pathways, thus resolving the contradiction between thermal performance and electrical safety
Solution Approach 2:
The linear polymer acts as an intermediary between ceramic particles and the reactive polymer matrix. It provides a compatible bonding interface that prevents particle aggregation and maintains uniform distribution, thereby avoiding the formation of large holes that would compromise electrical insulation while preserving thermal stability
2Strength
If adhesive percentage is increased to improve adhesion between ceramic particles and substrate, then adhesion is improved, but ion conductivity is lowered
Solution Approach 1:
The invention changes the chemical parameters of the adhesive system by using a reactive polymer that undergoes cross-linking reactions. This transforms the adhesive from a simple binding agent into a structurally integrated network that provides strong adhesion with minimal thickness, thereby maintaining ion conductivity pathways while achieving superior adhesion strength
Solution Approach 2:
The adhesive system is segmented into two functional components: reactive polymer for adhesion and linear polymer for ion conductivity. This segmentation allows each component to optimize its specific function - the reactive polymer forms strong bonds with ceramic particles and substrate, while the linear polymer maintains a more open structure that facilitates ion transport
3Reliability
If ceramic particle percentage is increased to enhance ion conductivity, then ion conductivity is improved, but adhesion deteriorates requiring more adhesive
Solution Approach 1:
The dual-polymer composite adhesive system provides enhanced binding strength that can accommodate higher ceramic particle loading. The reactive polymer creates a cross-linked network that firmly anchors ceramic particles, while the linear polymer ensures uniform distribution and interfacial bonding, allowing high ceramic content (up to 90 wt%) to be maintained without adhesion failure
4Reliability
If plasticizer or non-solvent is added to adhesive to increase ion conductivity, then ion conductivity is improved, but thermal stability is reduced as plasticizer must be removed at high temperature causing adhesive melting
Solution Approach 1:
The linear polymer component acts as a temporary facilitator during processing that enables high ceramic loading and good ion conductivity, but unlike plasticizers, it does not require removal. It remains in the final structure providing continuous ion pathways without compromising thermal stability, as it is thermally stable and does not migrate or evaporate
Solution Approach 2:
The combination of reactive polymer and linear polymer creates a composite adhesive that inherently provides both ion conductivity and thermal stability. The linear polymer's flexible chains create ion pathways while its thermal stability matches that of the ceramic particles, eliminating the need for thermally unstable plasticizers
5Temperature
If high heat tolerance adhesive materials are used to improve thermal stability, then thermal stability is improved, but ion conductivity is reduced due to dense cross-linking network
Solution Approach 1:
The adhesive is segmented into reactive polymer (for thermal stability and adhesion) and linear polymer (for ion conductivity). The linear polymer's un-crosslinked structure provides free volume and chain mobility that facilitate ion transport, while the reactive polymer matrix provides thermal stability, creating a balanced dual-function system
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 dual binder system maintains structural integrity and ion conductivity at high temperatures, reducing the risk of micro-shorts and enhancing overall battery performance by balancing electrical insulation and ionic conductivity.
Implementation Method 1
The dual binder system includes a linear polymer and a cross-linking polymer
Implementation Method 2
The ceramic separator is disposed between the first electrode substrate and the second electrode substrate... permit ion migration
Implementation Method 3
The dual binder system includes a linear polymer and a cross-linking polymer... maintains structural integrity and ion conductivity at high temperatures
Implementation Method 4
The separators are used to electrically insulate the negative and positive electrode layers... high electrical resistance
Data Source
Figure 1A
Figure 1B
Figure 2
AI summary
An electricity supply element and the ceramic separator thereof are provided. The ceramic separator is adapted to separate two electrode layers of the electricity supply element for permitting ion migration and electrical separation. The ceramic separator is made of ceramic particulates and the adhesive. The adhesive employs dual binder system, which includes linear polymer and cross-linking polymer. The adhesion and heat tolerance are enhanced by the characteristic of the two type of polymers. The respective position of the two electrode layers are maintained during high operation temperature to improve the stability, and battery performance. Also, the ceramic separator enhances the ion conductivity and reduces the possibility of the micro-short to increase practical utilization.