Cellulose Separator Flame Retardant Integration for Thermal Runaway
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current battery separators lack effective methods for incorporating flame retardants without compromising thermal stability or increasing the risk of short circuits during thermal runaway.
Innovation Solution
A cellulose-based separator incorporating modified cellulose fibers and a flame retardant, where the flame retardant is either trapped within or attached to the cellulose fibers through electrostatic or hydrogen bonding interactions, or covalently bonded to the fibers or a ceramic support.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If phosphate-based flame retardant additives are added to electrolytes, then thermal stability is improved, but electrolyte viscosity increases and performance deteriorates
Solution Approach 1:
The patent extracts the flame retardant function from the electrolyte by incorporating it into the separator material. The separator contains flame retardant particles (such as magnesium hydroxide, aluminum hydroxide, or boron compounds) that provide thermal stability without being dissolved in the electrolyte, thus avoiding viscosity increase and performance loss while maintaining effective flame retardancy.
Solution Approach 2:
The separator acts as an intermediary carrier that delivers flame retardant functionality to the battery system. Instead of adding flame retardants directly to the electrolyte, the separator serves as a medium that contains and releases flame retardant particles when needed, particularly during thermal runaway conditions when the separator melts or decomposes.
2Temperature
If synthetic polyimide separators are used to improve thermal stability, then heat resistance is enhanced, but manufacturing complexity increases
Solution Approach 1:
The patent creates a composite separator by combining cellulose base material with flame retardant particles and ceramic coatings. This composite structure achieves heat resistance comparable to synthetic polyimide separators (maintaining integrity up to 200°C or higher) while using naturally abundant, easily processable cellulose fibers that can be manufactured through conventional paper-making techniques, significantly reducing manufacturing complexity.
Solution Approach 2:
The patent modifies the physical and chemical parameters of cellulose separators by incorporating flame retardant particles and ceramic coatings, transforming them from flammable materials to heat-resistant separators. The cellulose separator's thermal stability is enhanced through these additions, allowing it to withstand temperatures that would normally cause melting and short circuits, while maintaining the simplicity of cellulose-based manufacturing processes.
3Ease of manufacture
If traditional polyethylene or polypropylene separators are used, then ease of manufacture is maintained, but thermal stability is insufficient leading to short circuits
Solution Approach 1:
The patent transforms traditional polyethylene or polypropylene separators into composite structures by incorporating flame retardant particles (such as metal hydroxides or boron compounds) and ceramic coatings. This composite approach maintains the ease of manufacturing associated with conventional plastic separators while dramatically improving thermal stability, allowing the separator to resist melting and maintain structural integrity at temperatures above 150°C, thereby preventing short circuits during thermal runaway.
4Reliability
If flame retardant is incorporated into polymeric separator, then thermal stability is improved, but additional short-circuit risk occurs when flame retardant releases upon melting
Solution Approach 1:
The patent extracts the flame retardant particles from the polymer matrix structure and incorporates them as discrete particles within the separator or on its surface. This approach allows the flame retardant to remain physically separated and contained within the separator structure, preventing premature release. The particles are embedded in a way that they only become active during actual thermal runaway conditions, eliminating the risk of short-circuit induction during normal operation.
Solution Approach 2:
The patent uses inexpensive inorganic flame retardant particles (such as magnesium hydroxide, aluminum hydroxide, or boron compounds) that are inherently stable and do not require complex polymer matrices for containment. These particles can be简单地 incorporated into the separator structure and remain stable throughout the battery's operational life, providing passive fire protection without active release mechanisms that could cause short circuits.
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 cellulose-based separator with integrated flame retardants demonstrates enhanced thermal stability and reduced risk of thermal runaway, maintaining mechanical integrity and porosity while effectively delaying combustion.
Implementation Method 1
the flame retardant is either trapped within or attached to the cellulose fibers through electrostatic or hydrogen bonding interactions
Implementation Method 2
the flame retardant is either trapped within or attached to the cellulose fibers through electrostatic or hydrogen bonding interactions
Implementation Method 3
covalently bonded to the fibers or a ceramic support
Data Source
AI summary
The present technology relates to a flame retardant, a cellulose fiber separator containing the flame retardant, a component comprising the separator and an electrolyte, and electrochemical cells and batteries comprising same as well as the uses thereof.