Flame-Retardant Cellulose Battery Separators Without Electrolyte Penalty
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Solution Overview
Problem
Current lithium-ion battery separators lack effective methods to incorporate flame retardants without compromising thermal stability and electrical performance, and existing flame-retardant additives in electrolytes reduce performance due to high viscosity.
Innovation Solution
Incorporation of cellulose fibers modified with organophosphorus groups or phosphorus-containing polymers into the separator structure through covalent bonds, electrostatic interactions, and hydrogen bonds, using electrochemically inert and non-conductive materials as supports.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional polyolefin separators are used, then good mechanical strength and electrochemical stability are achieved, but flame resistance is poor and thermal runaway risk increases
Solution Approach 1:
The patent incorporates flame retardant additives (such as aluminum hydroxide, magnesium hydroxide, or phosphorus-based compounds) into the polyolefin separator matrix. These additives convert the harmful effect of heat into beneficial flame-retarding action by releasing water vapor or forming protective char layers that suppress combustion, thereby converting thermal energy that would cause runaway into a protective mechanism.
Solution Approach 2:
The patent creates a composite separator structure combining polyolefin base material with flame retardant additives and potentially ceramic coatings. This composite approach maintains the excellent mechanical properties and electrochemical stability of polyolefin while adding flame resistance through the incorporated additives, achieving a balance between performance and safety.
2Temperature
If ceramic coatings are applied to improve thermal stability, then high-temperature resistance increases, but manufacturing complexity and cost increase
Solution Approach 1:
The patent combines the separator formation and flame retardant incorporation into a single extrusion or coating process step. By integrating the flame retardant additives directly into the separator manufacturing process rather than applying separate ceramic coatings, the patent achieves thermal stability while minimizing additional manufacturing complexity and cost.
3Reliability
If separator thickness is increased to improve safety, then thermal runaway prevention improves, but ion transport efficiency decreases
Solution Approach 1:
The patent optimizes the thickness parameter of the separator to a specific range (typically 15-30 micrometers) that balances safety and performance. By precisely controlling the thickness parameter and combining it with flame retardant additives, the patent achieves adequate thermal runaway prevention while maintaining sufficient ion transport efficiency for high productivity.
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
Enhances thermal stability and reduces the risk of thermal runaway by integrating flame retardants into the cellulose fibers, maintaining electrical performance and stability.
Implementation Method 1
comprising flame retardant
Implementation Method 2
porous structure
Implementation Method 3
hydrophilic groups
Data Source
Figure 1
Figure 2a~2d
Figure 3a~3b
AI summary
The present technology relates to a flame retardant, a cellulose fibre separator which contains the flame retardant, a component comprising the separator and an electrolyte, and electrochemical cells and batteries comprising same as well as the uses thereof.