Multilayer Battery Electrode Coating for Through-Hole Slurry Control
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Solution Overview
Problem
The manufacturing process of secondary battery electrodes faces challenges such as slurry leakage through the through-holes of the current collector, leading to surface irregularities and non-uniformity of the electrode mixture layer, which affects the battery's energy density and rapid charging characteristics.
Innovation Solution
A method of manufacturing a multilayer electrode by applying a first slurry with higher viscosity than a second slurry on an electrode current collector with through-holes, ensuring that the first slurry prevents leakage and forms a uniform initial layer, followed by the application of the second slurry to create a uniform electrode mixture layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a current collector with high porosity or aperture ratio is used to preserve lithium ion movement, then lithium ion conductivity is improved, but slurry leakage occurs through the through-holes causing surface irregularity
Solution Approach 1:
The patent applies different viscosity characteristics to different layers of the electrode mixture. The first electrode mixture layer has higher viscosity to prevent leakage through through-holes, while the second layer has lower viscosity for uniform coating. This local differentiation of material properties resolves the contradiction between maintaining porosity for ion conductivity and preventing slurry leakage for surface uniformity.
2Quantity of substance
If the electrode mixture layer is thickened to increase capacity, then battery capacity is improved, but energy density decreases and rapid charging characteristics deteriorate
Solution Approach 1:
The patent divides the electrode mixture layer into multiple thin layers (first electrode mixture layer and second electrode mixture layer) instead of using a single thick layer. This segmentation maintains the total active material quantity for high capacity while improving energy density and rapid charging characteristics by reducing the thickness of each individual layer, allowing better electrolyte penetration and lithium ion diffusion.
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 secures processability by preventing slurry leakage and ensures the formation of a uniform electrode mixture layer, enhancing the energy density and rapid charging characteristics of the secondary battery.
Implementation Method 1
applying a first slurry having a specific viscosity range to at least one surface of the electrode current collector... Viscosity of the first slurry is greater than viscosity of the second slurry
Implementation Method 2
electrical energy is generated by oxidation and reduction reactions when lithium ions are inserted and desorbed from the positive electrode and the negative electrode
Implementation Method 3
electrodes may be prepared by applying the slurry to a current collector of a metallic material, followed by being compressed and dried
Data Source
Figure 1
AI summary
An electrode for secondary battery comprising: an electrode current collector in which a plurality of through-holes are formed; a first electrode mixture layer including an electrode active material, a binder, a conductive material, and 0.5 to 2 % by weight of a thickener based on the total weight of the mixture, on at least one surface of the electrode current collector; and a second electrode mixture layer including an electrode active material, a binder, and a conductive material on the first electrode mixture layer, wherein the second slurry further comprises a thickener in a weight less than a weight of a thickener included in the first slurry. In manufacturing an electrode including an electrode current collector with a plurality of through-holes, processability may be secured by preventing leakage of a slurry, and thus, a uniform electrode mixture layer may be formed.