Preparation of Ceramic Layer by Ultrasonic Spraying Machine

The ultrasonic spraying machine can be fully used for the preparation of this ceramic layer, and has significant advantages in process adaptability and performance guarantee. The specific analysis is as follows:

The compatibility between the technical characteristics of ultrasonic spraying machine and the requirements for ceramic layer preparation

Micro scale thickness precise and controllable, compatible with mainstream specifications of 1-6 μ m
Ultrasonic spraying machine atomizes ceramic slurry into fine particles (droplet size can be controlled between 5-50 μ m) through ultrasonic vibration (frequency usually 20-180kHz), and then achieves precise control of coating thickness by adjusting parameters such as nozzle movement speed, slurry flow rate, and ultrasonic power. For the 1-6 μ m ceramic layer required in the previous section, the thickness uniformity error can be controlled within ± 5%, which can avoid the problems of “local excessive thickness leading to increased ion transport resistance” or “local excessive thickness causing thermal shrinkage risk”, and meets the core requirement of “directional regulation of multiple physical and chemical processes in batteries”.

The atomization process has no high-pressure impact, protecting the integrity of the base film
As mentioned earlier, the ceramic diaphragm base film is made of polymer materials such as PE/PP (melting point 135-160 ℃, low mechanical strength). Traditional high-pressure spraying is prone to wrinkling and damage to the base film due to airflow impact, while ultrasonic spraying relies on ultrasonic vibration atomization, which does not require high-pressure airflow and has minimal mechanical damage to the base film. At the same time, the atomized ceramic slurry is deposited at low speed on the surface of the base film, which can reduce particle agglomeration, form a uniform coating, avoid “shrinkage of uncoated areas”, and lay the foundation for the construction of subsequent “thermal resistance barriers” and “multi-layer particle protection barriers”.

Excellent dispersion of inorganic particles ensures a dense coating structure
The thermal stability (dependent on the high melting point characteristics of Al ₂ O ∝) and puncture resistance (dependent on the rigid network of particle stacking) of ceramic layers require the uniform dispersion of inorganic particles in the coating. The atomization process of ultrasonic spraying machine generates high-frequency vibration, which can further disperse the slightly agglomerated Al ₂ O3/boehmite particles in the slurry, and the uniformity of the droplets is high, forming a coating with dense particle accumulation and uniform pore distribution. This structure not only conforms to the characteristics of “strong support of thick coatings” (multiple layers of particles, dense rigid network), but also can balance the relationship between “ion migration path” and “electrolyte infiltration” by regulating the porosity (avoiding the sudden increase of ion resistance caused by too large pores or the impact of too small pores on infiltration speed).

Process adaptability and practical application advantages

Compatible with multiple types of ceramic slurries, suitable for different particle systems
Ultrasonic spraying has a wide compatibility with ceramic slurries. Whether it is a single system of Al ₂ O Ⅲ, boehmite, or a mixed inorganic particle system, as long as the viscosity (usually controlled at 200-1000cP) and solid content (20% -60%) of the slurry are adjusted to the appropriate range, stable preparation can be achieved. This can meet the material requirements mentioned earlier that ceramic coatings are mostly composed of inorganic particles such as Al ₂ O3 and boehmite, and the hydrophilicity of the coating can be further optimized by adjusting the slurry formula (such as increasing the hydroxyl content of Al ₂ O3) to enhance the electrolyte infiltration effect.

Continuous production efficiency is high, suitable for industrial applications
The demand for ceramic diaphragms in the current industry is growing on a large scale. Ultrasonic spraying machines can achieve roll to roll (R2R) continuous production, seamlessly connecting with the continuous unwinding and drying process of base films. The coating preparation speed can reach 1-5m/min, meeting the needs of industrial mass production. At the same time, its process parameters (such as thickness and uniformity) can be precisely controlled through an automated system, reducing human errors, ensuring consistency in the performance of ceramic layers between batches, and avoiding the comprehensive control effect of “thermal stability, mechanical strength, and ion transport” affected by thickness fluctuations.

Process optimization directions to be noted

Matching of slurry viscosity and ultrasonic parameters
If the viscosity of the slurry is too high, it can easily lead to insufficient atomization and agglomeration of coating particles; If the viscosity is too low, it may cause coating sagging and affect thickness uniformity. It is necessary to adjust the solid content and dispersant dosage of the slurry according to the particle size (such as commonly used 100-500nm for Al ₂ O ∝), and match the corresponding ultrasonic frequency (high frequency for fine particles and low frequency for coarse particles) to ensure the atomization effect.

The synergy between drying process and coating adhesion
The previous text emphasized the interface bonding force between the ceramic layer, the base film, and the electrode (such as the “physical bite” effect). After ultrasonic spraying, the slurry solvent needs to be removed by low-temperature drying (temperature lower than the melting point of the base film, usually 80-120 ℃) to avoid deformation of the base film caused by high temperature. At the same time, the internal stress of the coating can be reduced by adjusting the drying rate (slow heating), improving the adhesion between the ceramic layer and the base film, and avoiding the impact of coating detachment on interface stability during the cycling process.

About Cheersonic

Cheersonic is the leading developer and manufacturer of ultrasonic coating systems for applying precise, thin film coatings to protect, strengthen or smooth surfaces on parts and components for the microelectronics/electronics, alternative energy, medical and industrial markets, including specialized glass applications in construction and automotive.

Our coating solutions are environmentally-friendly, efficient and highly reliable, and enable dramatic reductions in overspray, savings in raw material, water and energy usage and provide improved process repeatability, transfer efficiency, high uniformity and reduced emissions.

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