Battery Separator Crosslinking for Strength and Insulation
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Solution Overview
Problem
Conventional methods for improving the physical properties of separators, such as insulation and tensile strength, are inadequate, particularly for lithium secondary batteries, and existing approaches require changes to the manufacturing process or composition, whereas a method to enhance already manufactured separators is lacking.
Innovation Solution
A post-treatment method involving the formation of crosslinkable sites on a binder molecule in a separator, using deintercalation to transform single bonds into double bonds, followed by treatment with a crosslinking initiator and/or catalyst, which can include inorganic particles and specific binders like PVdF, to enhance mechanical and insulation properties without altering the manufacturing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional separator manufacturing methods are used, then production process simplicity is maintained, but insulation resistance and mechanical strength are insufficient
Solution Approach 1:
The patent applies preliminary action by incorporating crosslinkable functional groups (such as vinyl, vinylidene, or allyl groups) into the binder molecule structure during separator manufacturing. This preliminary modification enables subsequent crosslinking treatment to significantly enhance mechanical strength and insulation resistance without fundamentally changing the manufacturing process flow.
Solution Approach 2:
The patent utilizes parameter changes by transforming the chemical structure of the binder through crosslinking reactions. The crosslinking process changes the molecular parameters of the binder, creating a three-dimensional network structure that dramatically improves the separator's mechanical strength and electrical insulation properties.
2Reliability
If crosslinking treatment is applied to enhance insulation properties, then electrical insulation improves, but process complexity increases
Solution Approach 1:
The patent employs an intermediary approach by using crosslinking initiators or catalysts as mediators to facilitate the crosslinking reaction. These intermediaries enable the crosslinking process to proceed under milder conditions with better control, improving insulation resistance while managing process complexity through controlled chemical reactions.
3Strength
If binder crosslinking is performed to improve mechanical properties, then tensile strength increases, but manufacturing adaptability decreases
Solution Approach 1:
The patent achieves universality by developing a binder structure with crosslinkable functional groups that can be applied to various separator types and manufacturing methods. The crosslinking treatment can be integrated into existing manufacturing processes, making the solution adaptable to different production scenarios while consistently improving tensile strength.
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 method effectively increases the insulation and tensile strength of separators, applicable to both polyolefin and non-polyolefin substrates, offering improved performance without modifying the existing production processes, thus enhancing the stability and lifespan of lithium secondary batteries.
Implementation Method 1
transforming the binder into a crosslinkable coupling part by deintercalation of some elements of the binder
Implementation Method 2
crosslinking the crosslinkable sites to improve insulation properties and mechanical properties of the separator
Data Source
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AI summary
Disclosed herein is a method for improving physical properties of a separator in which is capable of increasing insulation, tensile strength and elongation, and a separator having improved physical properties through the above method. Particularly, the present invention is applied to a separator already manufactured. After forming a double bond in the separator already manufactured, crosslinking may be formed through the double bond or by adding a separate crosslinking initiator.