Laval Nozzle Electrode Coating Without Solvent Drying or Calendering
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Solution Overview
Problem
Existing methods for coating anode and cathode plates in lithium-ion battery cells face issues such as high costs, energy consumption, wrinkling, poor adhesion, and complexity due to solvent use and calendering processes, which are not effectively addressed by dry coating alternatives.
Innovation Solution
A method using a Laval nozzle to apply a solvent-free coating by accelerating dry particles to supersonic speeds, allowing for direct adhesion to the carrier material without calendering, enabling multiple layers with varying densities and properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If wet coating with solvent is used, then coating adhesion is improved, but energy consumption increases due to solvent drying
Solution Approach 1:
The patent removes the solvent component from the coating process entirely, using only dry powder active material and binding material. This extraction of the harmful solvent element eliminates the need for energy-intensive drying operations while maintaining coating integrity through alternative adhesion mechanisms.
Solution Approach 2:
The patent replaces the thermal drying process (heat-based) with a mechanical/physical deposition process using a Laval nozzle. The supersonic gas stream mechanically propels particles onto the substrate, substituting thermal energy with kinetic energy for the coating deposition.
2Quantity of substance
If calendering process is used for densification, then specific capacitance is improved, but device complexity increases
Solution Approach 1:
The patent replaces the complex mechanical calendering system with a simpler Laval nozzle-based particle deposition system. The supersonic gas stream naturally densifies the coating during deposition, eliminating the need for separate calendering equipment and operations.
Solution Approach 2:
The patent combines the coating deposition and densification operations into a single step using the Laval nozzle. The supersonic particle stream simultaneously deposits material and compacts it, merging two previously separate processes into one integrated operation.
3Adaptability or versatility
If multiple coating-calendering cycles are performed for different densities, then layer differentiation is improved, but production time increases
Solution Approach 1:
The patent introduces dynamic control parameters (gas stream velocity, particle feed rate, nozzle-to-substrate distance) that allow real-time adjustment of coating density during deposition. This dynamic control enables different density layers to be created in a single pass without repeated cycling.
Solution Approach 2:
The patent segments the coating process into controllable parameter zones, where different regions of the substrate or different time periods during deposition can receive different parameter settings to create layers with different densities, all within one continuous operation.
4Adaptability or versatility
If substrate is rewound after each process step, then process flexibility is improved, but particle contamination increases
Solution Approach 1:
The patent combines multiple process steps (coating, drying, calendering) into a single continuous operation using the Laval nozzle. This eliminates intermediate rewinding operations that cause contamination, as the entire process occurs in one continuous pass without substrate handling interruptions.
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
Achieves high-density coatings with improved adhesion and reduced production time and costs by eliminating the need for calendering and solvent use, while allowing for precise control of layer properties.
Implementation Method 1
a gas stream is accelerated by a Laval nozzle to a supersonic velocity
Implementation Method 2
The Laval nozzle has a converging first section, a second section with a smallest flow cross-section and a diverging third section arranged sequentially along a flow direction
Implementation Method 3
The accelerated particle stream is applied to the carrier material to form a layer of a coating
Implementation Method 4
The binding material adheres the active material to the carrier material, so that a calendering process is no longer necessary
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
Method for coating a carrier material (1) with an active material (2) for producing an electrode foil (3) of a battery cell (4) with a Laval nozzle (5), wherein the Laval nozzle (5) is arranged successively along a flow direction (6) and has at least a converging first section (7), a second section (8) with a minimum flow cross-section (9) and a diverging third section (10).