Plasma-Treated Battery Anode Collector for Adhesion Control
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Solution Overview
Problem
Lithium secondary batteries face issues with reduced adhesion between the electrode mixture layer and the current collector, leading to degraded charge/discharge rate characteristics and safety concerns due to potential separation of the current collector and mixture layer, which can result in a reversed N/P ratio and unrolling of the negative electrode mixture layer.
Innovation Solution
A negative electrode for lithium secondary batteries is developed with a surface-treated current collector using atmospheric pressure plasma, incorporating an alkyl group with 1 to 6 carbon atoms in a mixed gas of inert and hydrocarbon gases, achieving a static water contact angle of 60° to 100° and peel strength of 10 gf/cm to 50 gf/cm, enhancing adhesion and preventing N/P ratio reversal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the binder content of the electrode mixture layer is increased to improve adhesion between the electrode mixture layer and current collector, then adhesion is improved, but battery performance is reduced because the content of electrode active material and conductive material is relatively reduced
Solution Approach 1:
The current collector surface is treated to create local hydrophobic regions with specific contact angles (30°-60°), which locally enhances adhesion through controlled wetting behavior without requiring increased binder content throughout the entire electrode structure
Solution Approach 2:
The surface properties of the current collector are modified by changing the contact angle parameter through hydrophobic treatment, which fundamentally alters the adhesion mechanism from chemical bonding to physical wetting control, allowing improved adhesion without adding binder material
2Strength
If the surface structure of the current collector is modified or a primer layer is formed to improve adhesion, then adhesion is improved, but safety problems occur because the contact angle formed by the negative electrode mixture layer and current collector is reduced, causing N/P ratio reversal
Solution Approach 1:
The contact angle parameter is precisely controlled within the optimal range of 30°-60° through hydrophobic surface treatment, which simultaneously achieves improved adhesion while preventing N/P ratio reversal by maintaining appropriate contact angle geometry
Solution Approach 2:
The conventional approach of modifying surface structure or adding primer layers is replaced with a chemical surface treatment that modifies surface energy and contact angle properties, achieving adhesion improvement without structural changes that could cause N/P ratio reversal
3Strength
If the contact angle is reduced to improve adhesion, then adhesion is improved, but the N/P ratio between positive electrode and negative electrode is reversed, causing safety problems
Solution Approach 1:
The contact angle is optimized to a specific range (30°-60°) that balances adhesion requirements with N/P ratio maintenance, preventing safety issues while achieving sufficient bonding strength
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 solution improves the adhesion between the negative electrode current collector and mixture layer, preventing unrolling and N/P ratio reversal, thereby enhancing the safety and performance of lithium secondary batteries.
Implementation Method 1
surface-treating a negative electrode current collector with atmospheric pressure plasma
Implementation Method 2
the negative electrode current collector has a static water contact angle of 60° to 100°
Data Source
AI summary
A negative electrode for a lithium secondary battery and a method of manufacturing the negative electrode including a negative electrode current collector and a negative electrode mixture layer on at least one surface of the current collector. The negative electrode is manufactured by controlling a static water contact angle of a surface of a negative electrode current collector and an contact angle formed by an end portion of a negative electrode mixture layer and the negative electrode current collector, within a specific range by treating the surface of the negative electrode current collector with atmospheric pressure plasma. The adhesion between the negative electrode current collector and the negative electrode mixture layer may be improved, and the induction of a reversal of an N/P ratio between a positive electrode and a negative electrode in an electrode assembly and the occurrence of unrolling in the negative electrode mixture layer may be prevented.