Decoding the Craft of Coating: From "Traditional Techniques" to "Future Trends" Our Company Advances Diversified Coating Technologies for Higher Quality and Efficiency

In the precise chain of lithium-ion battery manufacturing, the coating process is like the "tailoring work" of battery production. Even slight unevenness in coating thickness can affect a battery’s range, safety, and service life. To achieve ultimate product performance, our technical team recently conducted an in-depth review of coating technologies, systematically sorted out the three mainstream coating methods in the industry, and implemented precise applications based on the characteristics of each process, providing diversified technical solutions for the production line.

Now, let’s unveil the "mystery" of these three coating methods and explore their unique strengths and limitations.

I. Comma Blade Coating: The Versatile "Traditional Craft" on the Production Floor

As a "classic" in Lithium battery coating, comma blade coating remains a mainstay on many production lines due to its high practicality.

Its working principle is similar to spreading cream on a cake with a spatula: slurry is poured onto moving copper or aluminum foil, and a high-precision arc-shaped comma blade scrapes off excess slurry, leaving a uniform coating on the substrate surface.

Core Advantages

1. Strong compatibility: Highly tolerant to slurry viscosity, solid content and other indicators; suitable for both conventional materials and special formulas, with a low debugging threshold.

2. Efficient and economical: Simple equipment structure, low maintenance cost, and easy operation. Ideal for small-batch trials, sample production, and mass production of conventional batteries, delivering excellent cost performance.

3. Flexible switching: Fast changeover between different product models or specifications, well adapting to the workshop’s multi-variety, small-batch production rhythm.

Inherent Disadvantages

1. Limited uniformity: Coating thickness uniformity is greatly affected by manual operation and blade wear, making it difficult to achieve micron-level precision.

2. Risk of substrate damage: Direct contact between the blade and foil may scratch the substrate if pressure is improperly controlled, reducing product yield.

3. Prone to edge defects: "Thick edges" often occur during long-distance coating, requiring post-processing such as polishing and increasing process complexity.

II. Slot Die Coating: The "Precision Leader" in High-End Manufacturing

If comma blade coating represents a "traditional craft", slot die coating is the "core technology" propelling the Lithium battery industry toward high-end applications. It is now widely used in production lines for power batteries, high-end energy storage batteries and other premium products.

It adopts an "extrusion coating" method: under pump pressure, slurry is evenly and continuously extruded onto high-speed moving substrates through a precision-machined slot die. The entire process is fully enclosed, with no contact between slurry and external air.

Core Advantages

1. Ultra-high precision: Coating thickness accuracy controlled within ±1 micron, with an extremely smooth surface and neat edges, fully meeting the strict consistency requirements of high-end batteries.

2. Extremely low loss: The closed system eliminates waste from slurry splashing and volatilization, significantly reducing raw material costs—especially suitable for high-value slurry production.

3. Compatible with high-speed lines: Stable operation on high-speed production lines with line speeds exceeding 80 meters per minute, a key guarantee for large-scale, high-efficiency production.

4. Wide compatibility: Suitable for advanced material systems including high-nickel cathodes and Silicon-based Anodes, laying a solid foundation for product technology upgrades.

Inherent Disadvantages

1. High entry cost: Expensive equipment investment, high initial capital input, and strict requirements for workshop space and cleanliness.

2. Complex maintenance: The die, as a core component, involves difficult cleaning, calibration and maintenance, requiring professional technicians and incurring high maintenance costs.

3. Sensitive to parameters: Vulnerable to changes in slurry viscosity, temperature and other parameters; a strict parameter monitoring system is required to avoid coating defects.

III. Dry Coating: The "Emerging Star" of a Green Future

As "carbon neutrality" and "green manufacturing" lead the industry trend, dry coating is moving from the background to the forefront, becoming a key development direction for future lithium battery technology.

It completely abandons the solvent-dependent (e.g., NMP) model of traditional wet coating. Active materials, conductive agents and binders are directly mixed into powder, then firmly "laminated" onto current collectors through high-temperature calendering and other processes.

Core Advantages

1. Extreme environmental protection and energy saving: Eliminates organic solvent volatilization and recovery from the source, with zero VOC emissions and greatly reduced energy consumption—a truly green process.

2. Improved energy density: Eliminating the solvent drying step optimizes the internal pore structure of batteries, theoretically significantly improving energy density and charge-discharge efficiency.

3. Lower overall cost: Long-term savings on equipment and operating costs for solvent recovery systems, while enhancing the volumetric energy density of batteries.

Inherent Disadvantages

1. High technical difficulty: Extremely demanding process, with strict requirements for powder formulation, mixing, calendering temperature, pressure and other parameters; not yet fully commercialized.

2. Large equipment investment: Core equipment such as dry presses and feeding systems involve high technical barriers, with high R&D and manufacturing costs.

3. Yield challenges: Controlling yield in large-scale production remains a common industry challenge under current technical conditions, with long debugging cycles.

Conclusion: Precise Selection Empowers High-Quality Development

From the versatile comma blade coating, to the precision-driven slot die coating, to the future-oriented dry coating, each process holds irreplaceable value.

At AOAO New Energy, we uphold the production philosophy of "adjusting measures to local conditions and implementing precise strategies". For conventional products, we leverage the flexibility of comma blade coating; for high-end markets, we maximize the high precision of slot die coating. Meanwhile, we look ahead and accelerate the R&D and trial production of dry coating technology, accumulating momentum for the company’s long-term development.

In the future, we will continue to deepen core coating processes, drive product upgrades through technological innovation, build brand strength with craftsmanship quality, and contribute the "AOAO Strength" to the green and efficient development of the lithium battery industry