Negative Electrode Plate Binder Distribution for Crack-Resistant Drying
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Solution Overview
Problem
In the preparation of secondary battery negative electrode plates, the emulsion-type binder tends to float and distribute unevenly during drying, leading to poor adhesion between the active substances and the current collector, resulting in issues like powder falling off and cracking, which negatively affects battery performance.
Innovation Solution
A negative electrode plate with an emulsion-type binder in irregular film-like distribution on the surface of the active material, achieved through pretreatment methods like ultrasonication, settling, or kneading, ensures improved adhesion and cohesion by altering the binder's distribution morphology.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional drying process is used, then water evaporates from negative electrode plate, but emulsion-type binder floats up and distributes unevenly
Solution Approach 1:
The patent applies preliminary action by conducting ultrasonic treatment and adding settling agents to the slurry before the drying process. These preliminary actions modify the binder's state and distribution in advance, preventing the binder from floating up during subsequent drying. The ultrasonic treatment disperses the binder uniformly, and settling agents prepare the slurry for controlled settling during drying, thereby maintaining composition stability throughout the drying process.
Solution Approach 2:
The patent employs parameter changes by modifying the physical and chemical parameters of the slurry system. Ultrasonic treatment changes the kinetic energy and distribution state of binder particles. Settling agents alter the density and settling characteristics of the slurry components. These parameter modifications enable the binder to maintain uniform distribution during water evaporation, resolving the contradiction between drying efficiency and composition stability.
2Strength
If binder distributes unevenly, then adhesion between active substances improves, but powder falling off and cracking occur
Solution Approach 1:
The patent uses preliminary action by applying ultrasonic treatment and settling agents before drying to achieve uniform binder distribution. This preliminary uniform distribution ensures that during subsequent battery operation, the binder maintains consistent adhesion across all active substance particles, preventing localized weak points that would lead to powder falling off or cracking, thereby improving reliability while maintaining strength.
Solution Approach 2:
The patent directly addresses the need for homogeneity by using ultrasonic treatment to disperse binder particles uniformly and settling agents to maintain this uniform distribution during drying. The resulting homogeneous binder distribution throughout the negative electrode plate ensures consistent adhesion properties, preventing the formation of weak zones that would cause powder detachment or structural cracking during battery cycling.
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 irregular film-like distribution of the binder enhances the mechanical stability and cycling performance of the battery by preventing binder migration and improving the bonding between the active material and the current collector.
Implementation Method 1
pretreatment methods like ultrasonication, settling, or kneading
Implementation Method 2
pretreatment methods like ultrasonication, settling, or kneading
Data Source
AI summary
A negative electrode plate includes a current collector and a negative electrode film layer disposed on at least one surface of the current collector. The negative electrode film layer includes a negative electrode active material and an emulsion-type binder. At least a portion of the emulsion-type binder is in irregular film-like distribution on surface of the negative electrode active material.