Battery Electrode Binder Solution Contact Angle Control
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Solution Overview
Problem
During the manufacturing of battery electrodes, rapid drying of the mixed material paste leads to convection currents, causing the binder to rise and collect at the surface, reducing adhesive strength between the current collector and the electrode mixture, which can result in the electrode peeling off during subsequent manufacturing steps or battery use, affecting performance.
Innovation Solution
A method involving the application of a binder solution with a contact angle of 73° or less on the current collector surface, followed by the deposition and joint drying of the mixed material paste, ensuring more binder is retained at the interface for enhanced adhesion and surface smoothness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the mixed material paste is dried rapidly, then productivity is improved, but the adhesive strength between the current collector and the electrode mixture decreases
Solution Approach 1:
A binder solution layer is applied to the current collector before applying the mixed material paste. This preliminary binder layer ensures that sufficient binder remains at the interface during rapid drying, maintaining adhesive strength while enabling high productivity through fast drying processes.
Solution Approach 2:
The binder solution acts as an intermediary layer between the current collector and the mixed material paste. This intermediate layer prevents binder depletion at the interface during rapid drying, resolving the contradiction between fast drying and maintaining adhesion.
2Strength
If the binder solution has high wettability (low contact angle), then the adhesive strength is improved, but the mixed material paste may slip during application
Solution Approach 1:
The contact angle of the binder solution is precisely controlled within the range of 5° to 73°. This parameter optimization balances wettability for strong adhesion with sufficient surface stability to prevent paste slipping during application.
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
This approach results in electrodes with improved adhesion to the current collector, achieving high cycle durability, superb output properties, and increased productivity, suitable for high-performance lithium secondary batteries used in vehicles.
Implementation Method 1
a binder solution that contains a binder and is adjusted so that a contact angle of the binder solution with a surface of the current collector is 73° or less
Implementation Method 2
by drying the deposited binder solution layer and mixed material paste layer together
Data Source
AI summary
The present invention provides a method for manufacturing a battery electrode. This method comprises the steps of applying a binder solution 50 that contains a binder 54 and is adjusted so that the contact angle of the binder solution 50 with the surface of a current collector 10 is 73° or less, to form a binder solution layer 56; applying a mixed material paste 40 containing an active material 22 on top of the binder solution layer 56, to deposit both the binder solution layer 56 and a mixed material paste layer 46 on the current collector 10; and obtaining an electrode 30 in which a mixed material layer 20 is formed on the current collector 10, by drying the deposited binder solution layer 56 and mixed material paste layer 46 together.