Secondary Battery Binder Composition for Heat-Shrink and Wetting Balance
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Solution Overview
Problem
Conventional binders for secondary battery functional layers face challenges in achieving both heat shrinkage resistance and electrolyte solution affinity, particularly when the thickness of the functional layer is reduced, which affects battery capacity and densification.
Innovation Solution
A binder comprising a particulate polymer with a cyano group-containing monomer unit, a cyclic ether-containing monomer unit, and a carboxyl group-containing monomer unit, where the cyclic ether-containing monomer unit has a proportional content of 5 mass % or more, is used to enhance heat shrinkage resistance and electrolyte solution affinity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the thickness of the functional layer is reduced to increase battery capacity, then battery capacity increases, but heat shrinkage resistance deteriorates
Solution Approach 1:
The invention changes the chemical composition parameters of the binder by incorporating specific monomer units (cyano group-containing, cyclic ether-containing, and carboxyl group-containing monomer units) in controlled proportions. This compositional parameter change enables the functional layer to maintain heat shrinkage resistance even at reduced thickness, thereby resolving the contradiction between increasing battery capacity and maintaining heat shrinkage resistance.
2Quantity of substance
If densification is performed to increase battery capacity, then battery capacity increases, but electrolyte solution injectability deteriorates
Solution Approach 1:
The invention modifies the chemical composition parameters of the binder by incorporating cyclic ether-containing monomer units (5-40 mass%) and carboxyl group-containing monomer units (1-20 mass%), which enhance electrolyte solution affinity. This parameter change improves electrolyte solution injectability even when the battery is densified, thereby resolving the contradiction between increasing battery capacity and maintaining electrolyte solution injectability.
3Ease of manufacture
If conventional binder composition is used to simplify manufacturing, then manufacturing complexity is reduced, but electrolyte solution affinity deteriorates
Solution Approach 1:
The invention creates a composite binder material comprising multiple specific monomer units (cyano group-containing, cyclic ether-containing, and carboxyl group-containing monomer units) in defined proportions. This composite material approach enhances electrolyte solution affinity while maintaining manufacturing feasibility, thereby resolving the contradiction between manufacturing simplicity and electrolyte solution affinity.
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 proposed binder effectively forms a functional layer with improved heat shrinkage resistance and electrolyte solution affinity, ensuring high adhesiveness and cycle characteristics of secondary batteries, even during densification.
Implementation Method 1
heat shrinkage resistance
Implementation Method 2
electrolyte solution affinity
Data Source
AI summary
Provided is a binder for a secondary battery functional layer that can form a functional layer having excellent heat shrinkage resistance and electrolyte solution affinity. The binder for a secondary battery functional layer contains a particulate polymer including a cyano group-containing monomer unit, a cyclic ether-containing monomer unit, and a carboxyl group-containing monomer unit. The proportional content of the cyclic ether-containing monomer unit in the particulate polymer is 5 mass % or more.