Separator Binder Coating Balancing Heat Resistance and Adhesion
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Solution Overview
Problem
Secondary battery separators face issues with heat resistance and adhesion to porous substrates, leading to mechanical contraction and potential short circuits when exposed to high temperatures, which existing technologies fail to adequately address.
Innovation Solution
A binder comprising a (meth)acrylic copolymer with structural units derived from (meth)acrylonitrile, (meth)acrylic acid or (meth)acrylate, and (acet)amides is applied to the separator, enhancing adhesion and heat resistance by adjusting the weight ratio of these units and incorporating inorganic particles to prevent shrinkage and improve lithium ion conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a separator is coated with an inorganic material to inhibit shrinkage, then heat resistance is improved, but adhesion to the porous substrate deteriorates
Solution Approach 1:
The patent uses a composite binder system comprising both acrylic copolymer and polyvinyl alcohol-based compound. The acrylic copolymer provides heat resistance while the polyvinyl alcohol-based compound enhances adhesion to the porous substrate. This composite approach allows both heat resistance and adhesion requirements to be satisfied simultaneously without compromising either property.
2Temperature
If acrylic copolymer is used as binder, then heat resistance is improved, but adhesion performance deteriorates
Solution Approach 1:
The polyvinyl alcohol-based compound acts as an intermediary substance that bridges the acrylic copolymer binder and the porous substrate. It enhances the bonding interface between the heat-resistant acrylic copolymer and the substrate, thereby improving adhesion performance while maintaining the heat resistance properties of the acrylic copolymer.
3Strength
If polyvinyl alcohol-based compound is added to improve adhesion, then adhesion performance is improved, but manufacturing complexity increases
Solution Approach 1:
The patent combines the acrylic copolymer and polyvinyl alcohol-based compound into a single integrated binder system applied in one coating process. This merging of materials and processes eliminates the need for separate application steps, thereby improving adhesion performance while avoiding significant increases in manufacturing complexity.
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 binder significantly improves the heat resistance and adhesion properties of the separator, reducing the risk of short circuits and maintaining battery stability even at elevated temperatures, while maintaining energy density and air permeability.
Implementation Method 1
a binder for coating a secondary battery separator including a (meth)acrylic copolymer... capable of greatly improving the heat resistance properties of a separator by improving adhesion and heat resistance to a porous substrate
Implementation Method 2
when the battery is exposed to a high temperature environment due to its non-ideal behavior, the separator is mechanically contracted or damaged due to melting characteristics at a low temperature... a technology capable of inhibiting the shrinkage of the separator and securing the stability of the battery by coating the separator with an inorganic material
Data Source
AI summary
The present disclosure relates to a binder for coating a secondary battery separator including a (meth)acrylic copolymer containing a first structural unit derived from (meth)acrylonitrile; a second structural unit derived from (meth)acrylic acid or (meth)acrylate; and a third structural unit derived from (acet)amides, and a separator for a secondary battery and a secondary battery including the same.