Lithium Battery Electrode Cross-Linked Polymer Adhesion
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Solution Overview
Problem
Lithium secondary batteries face challenges in maintaining adhesion between electrode collectors and active materials due to binder migration during high-temperature drying processes, leading to reduced battery performance and stability.
Innovation Solution
Incorporating a cross-linked polymer with an interpenetrating polymer network (IPN) in the electrode mixture layer, formed by a combination of first and second polymerization units, to enhance adhesion and prevent binder migration, thereby improving the distribution and retention of electrode materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a polymeric binder is used to improve electrode adhesion, then bonding force between electrode constituents is increased, but the binder moves with solvent during drying process causing weakened adhesion
Solution Approach 1:
The patent changes the molecular weight parameter of the binder from conventional ranges to ultra-high molecular weight (1,000,000 or more), which fundamentally alters the binder's behavior during processing. This parameter change enables the binder to maintain adhesion strength while resisting migration during drying, resolving the contradiction between bonding force and compositional stability
Solution Approach 2:
The patent creates a composite binder system by combining ultra-high molecular weight polymeric binder with specific additives and electrode materials. This composite approach enhances the binder's performance, allowing it to provide strong bonding while maintaining position stability during the drying process through synergistic interactions between components
2Strength
If high molecular weight binder is used to prevent binder migration, then adhesion force is improved, but viscosity increases causing feed filter clogging
Solution Approach 1:
The patent utilizes the parameter change of ultra-high molecular weight to achieve a counterintuitive effect: while high molecular weight typically increases viscosity, the specific polymer structure and processing conditions enable low-viscosity slurry formation. This resolves the contradiction by decoupling molecular weight from viscosity in the practical processing regime
Solution Approach 2:
The patent applies local quality control by optimizing the distribution and concentration of the ultra-high molecular weight binder in specific regions of the electrode slurry. This localized optimization ensures adequate adhesion force where needed while maintaining overall slurry flowability and filterability during manufacturing
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 cross-linked polymer network effectively maintains adhesion between the electrode collector and active materials, enhancing battery performance and stability by ensuring uniform distribution and solvent resistance, thus extending battery life and capacity.
Implementation Method 1
the cross-linked polymer is formed by a cross-linked bond between a first polymerization unit and a second polymerization unit to have an interpenetrating polymer network (IPN)
Implementation Method 2
the cross-linked polymer network effectively maintains adhesion between the electrode collector and active materials, enhancing battery performance and stability by ensuring uniform distribution and solvent resistance
Data Source
AI summary
The present invention relates to a secondary battery electrode including: a collector positioned between an external wire and an electrode active material to transfer electrons; and an electrode mixture layer coated on the collector, wherein the electrode mixture layer includes a cross-linked polymer, an electrode active material, and a binder, and the cross-linked polymer is formed by a cross-linked bond between a first polymerization unit and a second polymerization unit to have an interpenetrating polymer network (IPN), and a manufacturing method thereof.