Lithium-ion batteries account for a significant portion of the added value in an electric car or stationary energy storage equipment. Their production has
resulted in a variety of new and modified components cleaning chores.
Acp systems AG will demonstrate its quattroClean snow blasting technology, a dry, effective, and relatively cost cleaning method that is easily integrated
into automated battery and fuel cell production plants, at this year’s parts2clean. The technology allows for the reliable and repeatable removal of not only
particle contamination down to the submicrometer range, but also filmic-chemical contamination from partial or full surfaces. The cleaning medium is noncorrosive
liquid carbon dioxide produced as a by-product of chemical processes and energy generation from biomass. As a result, it is climate neutral.

The method is already being used to mass-produce lithium-ion batteries in a variety of applications. These include cleaning the contact surfaces of
prismatic, cylindrical (round), and pouch battery cells, as well as lead frames and printed circuit board bonding surfaces. Because even minor
contamination on joining surfaces might result in insufficient contact, particle and filmic contamination must be eliminated to assure performance and
safety.

Hydrogen-atmospheric oxygen fuel cells are also made using the dry technique. It is used to clean stainless steel alloy bipolar plates following laser
processing, for example. This leaves spatter remains on the surfaces, reducing efficiency and necessitating their complete removal. Particulate and filmic
contaminants from pre-processes such as punching are also cleaned using the dry, residue-free cleaning procedure. The wear-free dual-substance ring
nozzle of the quattroClean system is responsible for the system’s superior cleaning results.

Liquid carbon dioxide enters the nozzle and expands to generate fine CO2 crystals as it exits. These are then packed and propelled to supersonic speed by
a separate jacket jet of compressed air. It’s simple to focus the jet on a certain location. Four effective techniques (heat, mechanical, solvent, and
sublimation) ensure the reliable removal of impurities when they impinge on the cleaning surface. The compressed air’s aerodynamic force blows these
away from the surface, and the integrated suction mechanism expels them from the cleaning module. The treated surfaces/parts are dry and can be fed
directly to the next step in the production chain because the crystalline carbon dioxide sublimates completely during the cleaning step.
The quattroClean cleaning system’s flexibility and small size allow it to be put practically anywhere in an automated battery or fuel cell production line.
Through tests in ACP's technical centre, the process is designed and tested according to client and application requirements. A sensor system monitors the
uniformity of the jet at each nozzle to ensure consistent results. The blasting period, as well as the supply of compressed air and CO2 to the nozzles, are all
monitored. The measured values are automatically saved and can be sent to a superordinate system using conventional interfaces to obtain complete
production data. Acp systems AG will be exhibiting at parts2clean in Hall 4, Stand B 04, Messe Stuttgart, 5 to 7 October 2021.