Laval Nozzle Dry Coating for High-Density Battery Electrode Foils
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current processes for coating carrier materials for battery cells are inefficient, requiring multiple steps, high energy consumption, and resulting in poor adhesion and increased costs due to solvent use, calendering complexities, and difficulties in producing coatings with different densities.
Innovation Solution
A solvent-free coating process using a Laval nozzle to accelerate dry particles to supersonic speeds for high-density coating, eliminating the need for calendering and reducing energy consumption by directly adhering the active material to the carrier material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If wet coating with solvent is used, then coating application is easier, but energy consumption increases due to drying and solvent recycling
Solution Approach 1:
The invention extracts and eliminates the solvent component from the coating process. Instead of applying a slurry containing solvent (NMP or water) that requires subsequent drying and recycling, the patent uses a dry coating process where the active material is applied directly to the carrier material without any liquid carrier, thereby removing the energy-intensive drying and solvent recovery steps.
Solution Approach 2:
The invention replaces the wet chemical coating process with a mechanical/physical process. The dry coating is applied using a doctor blade or similar mechanical means, and the binder is activated through thermal processing rather than chemical solvents, substituting the wet chemical system with a dry mechanical-thermal system that consumes less energy.
2Manufacturing precision
If calendering is used to compress coating, then density and conductivity improve, but machine complexity and fold formation increase
Solution Approach 1:
The invention merges the coating application and compression steps into a single integrated process. The doctor blade serves dual functions: it applies the coating material and simultaneously compresses it to the desired density. This eliminates the need for separate calendering machines and complex multi-step processing, reducing machine complexity while achieving the required coating density and conductivity.
3Manufacturing precision
If multiple coating-calendering cycles are used for different densities, then layered coating quality improves, but production time increases
Solution Approach 1:
The invention introduces dynamic control of the doctor blade pressure and speed during the coating process. By varying the compression force applied by the doctor blade in real-time across different zones or during different passes, the process can create coatings with varying densities in a single continuous operation, eliminating the need for multiple static coating-calendering cycles and thereby maintaining productivity.
4Productivity
If rapid drying is used, then production efficiency improves, but adhesion decreases and cracks form
Solution Approach 1:
The invention extracts the solvent from the coating formulation entirely, eliminating the drying process. The dry coating material is applied directly and then thermally processed to activate the binder and achieve proper adhesion. This removes the fundamental conflict between drying speed and adhesion quality, as there is no solvent to evaporate that could cause rapid drying issues.
5Manufacturing precision
If heated calendering is used for dry coating, then binder distribution improves, but costs and energy consumption increase
Solution Approach 1:
The invention merges the binder activation and coating compression functions into a single thermal processing step that occurs immediately after coating application. The doctor blade applies the coating and applies sufficient compression during the same pass, and a single heating zone follows to activate the binder. This eliminates the need for separate heated calendering passes required in traditional dry coating methods, reducing energy consumption while maintaining binder distribution quality.
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 process achieves high-density coatings without calendering, reduces energy costs, and allows for the production of coatings with varying densities and properties, enhancing adhesion and reducing production time and costs.
Implementation Method 1
a first gas stream is introduced via a first portion into a Laval nozzle, wherein the Laval nozzle has at least one converging first portion, a second portion with a smallest flow cross section, and a diverging third portion arranged one after the other along a flow direction
Implementation Method 2
accelerating the particle stream via the first gas stream flowing at a supersonic speed in the third portion
Implementation Method 3
subjecting the carrier material to the first particle stream to form a layer of a coating
Data Source
AI summary
A process for coating a carrier material with an active material for production of an electrode foil of a battery cell with a Laval nozzle, wherein the Laval nozzle has at least one converging first portion, one second portion having a smallest flow cross section, and one diverging third portion arranged one after the other along a flow direction.