Four-Sided Film Applicator in laboratory battery research

In the laboratory research of new types of batteries such as lithium-ion batteries, solid-state batteries, and sodium-ion batteries, the uniformity of the electrode films directly determines the charging and discharging efficiency, cycle life, and safety of the batteries - if the thickness deviation of the electrode exceeds 5%, it may lead to uneven current distribution, local overheating, and even battery failure.Four-Sided Film Applicator, as an efficient film preparation tool,by virtue ofits core advantage of"being able to prepare four different thickness films in one operation", has become a key equipment in the research of battery electrodes (positive and negative electrodes), and solid-state electrolyte membranes.

The core working principle of the four-sided coating machine

The Four-Sided Film Applicator is essentially a film preparation equipment based on the "fixed gap scraping" principle. Its core logic is: by controlling the wet film thickness through the preset coating gap, and using the uniform scraping motion to achieve the uniform spreading of the slurry on the substrate (such as copper foil,Aluminum Foil, polymer substrate), finally, after drying, a controllable thickness functional film (such as battery electrode film, electrolyte film) is formed.

Compared with the traditional single-gap coating device, its core innovation lies in the four-sided design of the coating head - the same coating head integrates 4 independent scraping surfaces, and the”scraping edge - substrate”gap of each surface is different (common specifications such as 5um/10um/15um/20um, 20um/30um/40um/50um, etc.). When the coating head is moved uniformly along the substrate surface, the excess slurry is removed by the scraping edge, and only the wet film with the same thickness as the gap is retained; one operation can simultaneously prepare 4 different thickness films on the same substrate, significantly improving the experimental efficiency (especially suitable for "thickness-performance" relationship screening experiments).

The core components and technical characteristics of the four-sided coating machine

Coating head (core component)

It is made of stainless steel or tungsten carbide (high hardness, wear-resistant, avoiding gap deviation caused by blade wear). The four sides of the blade have been precisely ground, and the gap tolerance can be controlled within ±1um (standard of laboratory equipment). The gap of each blade can be customized according to research needs (common range: 5um - 100um, covering the typical thickness requirements of battery electrodes: the wet film thickness of the positive electrode is usually 20 - 50um, the dry film thickness is 10 - 25um; the wet film thickness of the solid-state electrolyte membrane is 10 - 30um).

Base fixation platform

Mostly made of anodized aluminum or optical glass, the surface flatness is ≤ 0.1mm/m (ensuring uniform gap between the base and the blade, avoiding local thickness deviation). Some high-end models are equipped with vacuum suction function, which can firmly fix the flexible base (such as copper foil, aluminum foil), preventing the base from shifting during coating.

Drive and positioning system

The handle is designed to follow ergonomic principles, facilitating the application of uniform force; the edge of the platform is equipped with millimeter-level positioning scales, which can precisely control the starting position of coating, ensuring that the films of four thicknesses do not overlap on the base (generally, it is recommended that the base size be ≥ 10cm × 15cm, leaving sufficient intervals). Some electric models can adjust the coating speed through motor control (5 - 50mm/s adjustable), further reducing human operational errors.

High gap accuracy:With a gap tolerance of ±1μm, it can meet the strict requirements of "thickness consistency" for battery electrodes (for example, the deviation of the dry film thickness of the positive electrode of lithium-ion batteries needs to be ≤3%);

Strong material compatibility:The scraper blade is resistant to acids and alkalis (able to withstand common solvents in battery pastes such as N-methylpyrrolidone (NMP) and water), and the platform can be adapted to various substrates including metal foils (copper, aluminum), polymer films (PET, PP), etc.;

High operational efficiency:It can prepare 4 different thicknesses in one operation, saving 75% of experimental time compared to a single gap coating device (especially suitable for "variable screening" experiments, such as testing the impact of different electrode thicknesses on battery rate performance).