Polyamide Porous Layer for High-Voltage Battery Durability
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Solution Overview
Problem
Nonaqueous electrolyte secondary battery porous layers, particularly those containing resins, face challenges in durability during high-voltage charge-discharge cycles, leading to a short circuit and reduced cycle life.
Innovation Solution
A nonaqueous electrolyte secondary battery porous layer is developed with a resin containing an amide bond, where a component is eluted into N-methylpyrrolidone in specific weight percentages, and a block copolymer structure with aromatic rings connected by sulfonyl bonds, enhancing durability and high-voltage resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the end-of-charge voltage is increased to not less than 4.3 V to increase utilization rates and capacities, then the battery capacity is improved, but the resin in the porous layer changes in quality and durability with respect to charge-discharge cycles deteriorates
Solution Approach 1:
The invention changes the chemical composition parameters of the resin by specifying precise proportions of wholly aromatic polyamide (6.0-25.0% by weight) and aromatic polyamide-imide (75.0-94.0% by weight). This parameter optimization allows the resin to maintain structural integrity and resist quality degradation even under high-voltage conditions (not less than 4.3 V), thereby improving both battery capacity and cycle durability simultaneously
Solution Approach 2:
The invention creates a composite resin system combining two different polyamide types with specific functional characteristics. The wholly aromatic polyamide provides high-voltage resistance while the aromatic polyamide-imide contributes to overall structural stability. This composite approach allows the porous layer to withstand the stresses of high-voltage operation and extended charge-discharge cycling without deteriorating
2Reliability
If a wholly aromatic polyamide with electron-withdrawing substituents is used to prevent color change under high voltage, then high-voltage resistance is improved, but the number of charge-discharge cycles until short circuit occurs is insufficient
Solution Approach 1:
The invention optimizes the weight ratio parameters of the resin components, specifically setting wholly aromatic polyamide at 6.0-25.0% and aromatic polyamide-imide at 75.0-94.0%. This precise parameter control ensures that the high-voltage resistance provided by the electron-withdrawing substituents in wholly aromatic polyamide is complemented by the cycle-stabilizing properties of aromatic polyamide-imide, achieving both high-voltage resistance and extended cycle life
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 solution significantly improves the durability of the battery with respect to charge-discharge cycles, increasing the number of cycles before a short circuit occurs and maintaining performance under high-voltage conditions.
Implementation Method 1
a contained amount of the component that is to be eluted into N-methylpyrrolidone being not less than 6.0% by weight and not more than 25.0% by weight relative to a total weight of the resin having the amide bond, where the contained amount of the component that is to be eluted into N-methylpyrrolidone is measured by carrying out extraction with respect to the nonaqueous electrolyte secondary battery porous layer using N-methylpyrrolidone
Data Source
AI summary
As a nonaqueous electrolyte secondary battery porous layer that is excellent in durability with respect to charge-discharge cycles, provided is a nonaqueous electrolyte secondary battery porous layer including a resin which has an amide bond and which contains a component that is to be eluted into N-methylpyrrolidone. A contained amount of the component that is to be eluted into N-methylpyrrolidone is not less than 6.0% by weight and not more than 25.0% by weight relative to a total weight of the resin having the amide bond.