Crosslinked Conductive Slurry for Battery Collector Adhesion
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Solution Overview
Problem
Lithium-ion batteries face issues with adhesion and conductivity between the active material layer and the current collector, leading to reduced cycle life and safety performance due to insufficient water resistance of the conductive coating when using aqueous solvents, which can cause the active material layer to detach from the substrate.
Innovation Solution
A conductive slurry comprising an aqueous binder with polycarboxyl functionality, a conductive agent, and a curing agent is used to form a three-dimensional cross-linked network structure, enhancing adhesion and conductivity while maintaining water resistance, ensuring stable operation and prolonged cycle life of the battery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a conventional aqueous binder is used in the conductive slurry, then the slurry has good processability and ease of application, but the adhesion strength and water resistance are insufficient, causing the active material layer to detach from the current collector
Solution Approach 1:
The patent changes the chemical parameters of the aqueous binder by introducing polycarboxyl functional groups and using crosslinking agents. This transforms the binder from a simple adhesive to a chemically active material that forms strong covalent bonds with both the current collector and active material layer, dramatically improving adhesion strength while maintaining aqueous processability
Solution Approach 2:
The patent creates a composite binder system combining polycarboxyl-functionalized aqueous polymer with crosslinking agents. This composite material exhibits both the ease of application of aqueous binders and the superior adhesion strength of chemically crosslinked networks, resolving the contradiction between processability and bonding strength
2Object-affected harmful factors
If the conductive coating uses aqueous solvent for environmental friendliness and safety, then the battery operates safely with reduced pollution, but the coating lacks water resistance, leading to detachment of the active material layer
Solution Approach 1:
The patent modifies the chemical parameters of the aqueous binder by introducing polycarboxyl functional groups and crosslinking agents. This transformation enables the coating to resist water penetration while maintaining the environmental benefits of using aqueous solvent, thus improving water resistance without sacrificing safety or environmental friendliness
Solution Approach 2:
The patent applies preliminary chemical modification to the aqueous binder before coating application. By pre-introducing polycarboxyl groups and crosslinking agents into the binder formulation, the coating is pre-equipped with water resistance properties, preventing detachment issues that would otherwise occur with conventional aqueous coatings
3Duration of action of stationary object
If the adhesion between active material layer and current collector is improved, then the cycle life of the battery is extended, but the conductivity may be compromised due to focus on bonding strength
Solution Approach 1:
The patent employs a composite material system that integrates conductive agents within the crosslinked binder matrix. This composite structure ensures that electrical conductivity pathways are maintained while the crosslinked network provides strong adhesion, thus improving cycle life without compromising electrical or cycling performance
Solution Approach 2:
The patent applies local quality enhancement by concentrating crosslinking density at the interface between the conductive coating and current collector, while maintaining conductive agent distribution throughout the coating. This localized strengthening improves adhesion and cycle life without interfering with the overall conductivity of the coating
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 conductive slurry improves the adhesion strength and conductivity between the active material layer and the current collector, maintaining structural integrity and cycle life, even when exposed to aqueous solvents, thereby enhancing the stability and performance of lithium-ion batteries.
Implementation Method 1
the curing agent is used for cross-linking reaction with the aqueous polymer having polycarboxyl functionality
Data Source
AI summary
This application provides a conductive slurry, a current collector, a secondary battery, a battery module, a battery pack, and an electric apparatus. The conductive slurry in this application includes the following raw material components: an aqueous binder including an aqueous polymer having polycarboxyl functionality, a conductive agent, a dispersant, and a curing agent, where the curing agent is used for cross-linking reaction with the aqueous polymer having polycarboxyl functionality. The conductive slurry in embodiments of this application has relatively good conductivity and adhesion performance as well as relatively good water resistance, which can improve stability of the secondary battery during operation and prolong its cycle life.