Water-Based Electrode Binder Crosslinking for Peel-Resistant Li-Ion Cells
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Solution Overview
Problem
Current binders for non-aqueous electrolyte secondary battery electrodes lack sufficient binding ability and durability, particularly in preventing peeling or detachment of electrode mixture layers, and do not meet the increasing demands for improved reliability and durability in lithium-ion secondary batteries.
Innovation Solution
A water-based binder containing a crosslinked polymer with a carboxyl group or its salt, derived from ethylenically unsaturated carboxylic acid monomers and macromonomers, is used to enhance binding to active materials and current collectors, improving the integrity and durability of electrode mixture layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional binders (SBR latex, CMC, acrylic acid polymer, PVDF) are used for electrode mixture layers, then the electrodes can be manufactured with standard processes, but the binding ability is insufficient and electrode mixture layers peel or detach during battery operation
Solution Approach 1:
The patent uses composite materials by combining acrylic acid polymer with silane crosslinking agents to create a crosslinked polymer network. This composite structure provides both the water-based compatibility of acrylic acid polymer and the enhanced mechanical strength and adhesion of the crosslinked silane network, resolving the contradiction between manufacturability and binding ability.
Solution Approach 2:
The patent changes the chemical and physical parameters of the binder by introducing crosslinking structures through silane treatment. This transforms the linear acrylic acid polymer chains into a three-dimensional crosslinked network, fundamentally changing the mechanical properties and adhesion characteristics to achieve superior binding ability while maintaining water-based formulation.
2Reliability
If binders are designed to improve binding ability through crosslinking, then adhesion improves, but the flexibility and processability of the binder may deteriorate
Solution Approach 1:
The patent applies preliminary action by pre-treating the acrylic acid polymer with silane agents before electrode assembly. The silane crosslinking is performed in advance during the binder preparation stage, allowing the crosslinked structure to form before the electrode mixture layer is applied. This preliminary crosslinking ensures durability while maintaining ease of manufacture because the crosslinking process is integrated into the existing binder preparation workflow.
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 provides excellent binding ability and adhesion to electrode materials and current collectors, preventing deterioration due to volume and shape changes during charge and discharge, resulting in a non-aqueous electrolyte secondary battery with improved cycle properties and durability.
Implementation Method 1
The binder provides excellent binding ability and adhesion to electrode materials and current collectors, preventing deterioration due to volume and shape changes during charge and discharge
Implementation Method 2
preventing deterioration due to volume and shape changes during charge and discharge
Data Source
AI summary
A water-based binder for a non-aqueous electrolyte secondary battery. A binder for a non-aqueous electrolyte secondary battery electrode, includes a crosslinked polymer having a carboxyl group or a salt thereof, and the crosslinked polymer includes a structural unit derived from an ethylenically unsaturated carboxylic acid monomer; and a structural unit derived from a macromonomer including at least one compositional monomer selected from compounds represented by following formula (1):[C1]H2C═CR1—X formula (1)wherein in formula (1), R1 represents a hydrogen or a methyl group; X represents C(═O)OR2 or CN; and R2 represents a straight chain or branched C1-C8 alkyl group or a C3-C8 alkyl group having an alicyclic structure.