Reciprocating Piston Slurry Mixer for Battery Electrode Coating
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Solution Overview
Problem
Conventional methods for forming and coating battery electrodes require significant energy, large equipment, and the use of toxic solvents, leading to inefficient processes and inconsistent results due to the complexity and space requirements of wet coating, as well as the irregular distribution of powders in dry coating.
Innovation Solution
A device and method that simultaneously mixes, kneads, and coats a slurry onto both sides of a substrate using a system of cylinders and pistons, applying shearing forces to homogenize the slurry, followed by freeze drying and vacuum heating to remove solvents, reducing the need for toxic chemicals and simplifying the manufacturing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional wet coating methods are used to coat slurry onto substrates, then the coating process can be performed, but large equipment space and complex devices are required
Solution Approach 1:
The patent combines the mixing, kneading, and coating functions into a single integrated device. The cylindrical chamber serves both as a mixing container and a coating applicator, eliminating the need for separate mixing equipment and coating equipment, thereby significantly reducing the overall equipment space required.
Solution Approach 2:
The cylindrical chamber performs multiple functions: it mixes the slurry, kneads the mixture, and applies the coating to the substrate. This multi-functional design replaces multiple specialized devices with a single versatile unit, reducing the total equipment footprint while maintaining process effectiveness.
2Ease of manufacture
If conventional planetary mixers are used to mix slurries, then the mixing can be performed, but long mixing times are required
Solution Approach 1:
The piston performs reciprocating periodic motion within the cylindrical chamber, creating repeated compression and expansion cycles. This periodic action enhances mixing efficiency by continuously repositioning and redistributing the slurry material, achieving homogeneous mixing faster than conventional continuous rotation mixers.
Solution Approach 2:
The patent changes the mixing mechanism from rotational motion to reciprocating linear motion with compression. The piston's back-and-forth movement creates varying pressure and volume conditions that enhance mixing efficiency and reduce the time required to achieve uniform slurry composition.
3Ease of manufacture
If toxic solvents are used in conventional wet coating slurries, then the slurry can be formed and applied, but elaborate drying systems are required to remove the solvents
Solution Approach 1:
The patent extracts and eliminates the toxic solvent component from the slurry formulation. By using a solvent-free or water-based slurry system, the need for elaborate drying systems to remove toxic solvents is eliminated, simplifying the overall process equipment while maintaining slurry formability and coating application capabilities.
4Object-affected harmful factors
If dry coating processes are used to coat powder onto substrates, then toxic solvents are avoided, but complex powder distribution arrangements are required
Solution Approach 1:
The patent combines powder mixing and coating application into a single integrated operation within the cylindrical chamber. The piston-driven mixing process simultaneously prepares the powder-slurry mixture and facilitates its transfer to the substrate, eliminating the need for separate complex powder distribution systems while maintaining solvent-free operation.
5Ease of manufacture
If conventional separate mixing and coating processes are used, then each process can be optimized, but the overall process complexity and time increase
Solution Approach 1:
The patent merges the mixing and coating processes into a single integrated operation. The cylindrical chamber serves as both the mixing container and the coating applicator, allowing the slurry to be mixed and applied in one continuous operation rather than requiring separate mixing and coating equipment and process steps.
Solution Approach 2:
The cylindrical chamber is designed to perform multiple functions sequentially: mixing the slurry components, kneading the mixture to achieve homogeneity, and then applying the coating to the substrate. This multi-functional approach maintains process optimization while reducing overall system complexity and eliminating intermediate transfer steps.
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 reduces the complexity and time required for slurry formation, eliminates the use of toxic solvents, and achieves consistent electrode coatings with improved porosity and adhesion, enhancing battery performance while minimizing environmental impact and equipment size.
Implementation Method 1
The repeated movement of the slurry through the tube applies a shearing force to the slurry, which mixes and kneads the slurry
Implementation Method 2
freeze drying the coated substrate
Implementation Method 3
heating the freeze-dried coated substrate under a vacuum at elevated temperatures to remove residual solvents
Data Source
AI summary
Devices and methods for preparing a slurry for coating onto a substrate. The devices and methods of the present disclosure relate to providing a slurry in a closed volume with at least one passage. The slurry includes a solvent, a powder, and a binder. The slurry can also include a dispersion agent. The slurry is forced repeatedly under high pressure through the at least one passage in a first flow direction and then back through the at least one passage in a second flow direction, opposite the first flow direction. The forcing homogenously disperses the powder and the binder within the solvent. Both sides of the substrate are then coated simultaneously with the slurry extruded from the closed volume after the forcing. Curing of the coated slurry includes freeze drying to preserve the porosity of the slurry on the substrate.