Electrode Coating Uniformity via Slurry Yield Stress Control
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Solution Overview
Problem
Nonaqueous electrolyte batteries face issues with non-uniform electrode coating, leading to uneven current distribution and reduced large-current performance due to variations in yield stress of the slurry during the coating process.
Innovation Solution
Decreasing the yield stress of the slurry to two-thirds or less by using a static mixer or other yield stress regulators to ensure uniform application on the current collector, thereby improving the uniformity of the coating amount and reducing internal electric resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the particle size of active material is reduced to increase specific surface area, then the contact area between active material and electrolyte is increased, but the coating thickness becomes non-uniform
Solution Approach 1:
The patent changes the rheological parameters of the slurry by reducing yield stress to one-third or less of the initial value. This parameter change allows the slurry to flow more uniformly through the die coater, producing consistent coating thickness even with fine particles that provide high specific surface area for improved large-current performance
Solution Approach 2:
The patent introduces a yield stress regulator as an intermediary device between the slurry preparation and coating processes. This regulator acts as a mediator that controls the flow characteristics of the slurry, ensuring uniform coating application while maintaining the beneficial properties of fine-particle active materials
2Ease of manufacture
If the coating amount is non-uniform, then the manufacturing process is simpler, but current concentrates on parts with decreased coating amount, causing quick deterioration
Solution Approach 1:
The patent modifies the slurry's yield stress parameter to enable uniform coating application. This parameter change ensures that current distributes evenly across the electrode surface, preventing concentration effects that would cause localized deterioration and maintain battery capacity during repeated charge-discharge operations
Solution Approach 2:
The patent implements a feedback mechanism where the yield stress regulator continuously adjusts slurry flow characteristics based on coating uniformity requirements. This feedback control ensures consistent coating thickness, which in turn ensures uniform current distribution and prevents localized overheating or deterioration
3Stability of the object's composition
If the yield stress of slurry is high, then the slurry structure is more stable, but the coating thickness becomes non-uniform when applied through die coater
Solution Approach 1:
The patent applies a yield stress regulator to change the rheological parameters of the slurry, specifically reducing yield stress to one-third or less of the initial value. This parameter transformation maintains slurry stability while enabling uniform flow through the die coater for consistent coating thickness
Solution Approach 2:
The patent introduces dynamic control of slurry flow characteristics through the yield stress regulator. The regulator dynamically adjusts the slurry's flow behavior, allowing it to maintain stability at rest while flowing uniformly during coating application, thus achieving both structural stability and coating uniformity
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 method results in a more uniform electrode coating, enhancing the large-current performance and maintaining battery capacity during repeated charge-discharge operations under high current conditions.
Implementation Method 1
decreasing a yield stress of a slurry containing an active material to two-thirds or less; and applying the slurry to a current collector
Data Source
AI summary
A method of producing an electrode including decreasing a yield stress of a slurry containing an active material to two-thirds or less, and applying the slurry to a current collector.