Efficient and reliable pretreatment for e-car components: PURIMA sets new standards#.

Order: Cleaning of safety-relevant components for the production of battery trays for e-vehicles | Challenge: complex geometries and high cleanliness requirements | Implementation: automated cleaning system of the ROTOTRONIC® type with 9-stage cleaning process | Process: Various (modules)

For a major customer from the automotive industry, PURIMA, a long-standing expert in special machine construction in the field of industrial parts cleaning based in Porta Westfalica, Germany, developed a system for pretreating components for the production of battery trays. The energy storage units of e-vehicles are installed in these. But the battery trays are much more than just storage space: they serve as the vehicle’s floor assembly and are among the relevant safety components. In the event of an accident, a floor assembly must be able to withstand various forces, because in the event of a fire, passengers must be protected for a certain period of time so that rescue can be made possible. It is therefore all the more important that the battery trays are properly prepared for further production steps during their manufacture. Based on the high requirements of the customer and the legislator, PURIMA implemented a modular plant that is characterized by a maximum degree of automation. In the plant, all safety-relevant components of a battery tray are pretreated in this way for welding and bonding.

Automated precision pretreatment system that fits in perfectly

As part of the production of battery trays, almost all components – before or after mechanical processing – are degreased, pickled and passivated for assembly by means of welding and bonding. The degreasing and pickling-passivation of the aluminum parts guarantees homogeneous surfaces. In this way, stable and durable joints can be achieved in the subsequent process with consistent welding parameters, which are necessary for the safe operation of an electric car. To avoid short circuits, the components must be free of chips and reproducibly dried at the end of pretreatment so as not to pose a safety risk during subsequent operation. This applies to all components such as profiles, floor assemblies, crash boxes or other small parts.

Another important requirement of the customer was the seamless integration of the plant technology into its existing process infrastructure. The goods carriers, which serve as a means of transport for the complex cleaning material, were to be automatically loaded and unloaded by robot with floor assemblies, profiles and small parts. The customer continued to place high demands on effective process visualization and traceability of all components handled in the plant.

Component cleaning E-mobility

Battery trays are safety-relevant components that must be cleaned without residue as part of their production.

Reaching the cleaning target with nine intermittent treatment stages

Together with world-renowned companies, PURIMA has implemented several major projects in recent years for the pretreatment of aluminum components for the production of battery trays and similar constructions. Based on the customer’s specifications and PURIMA’s many years of experience, the decision was made in favor of an immersion plant with nine treatment stages, a cyclical continuous dryer with an inlet sluice for energy saving, a cooling zone with energy recovery and a cooling zone. After the process, the components are ready for removal from the product carriers at approx. 30 °C. Pick-up, transfer to the different dipping baths and depositing of the product carriers on the cross conveyor to the dryer is carried out by 3 automatic transport systems. Thus, critical treatment times in the degreasing stages and in the pickling passivation are maintained and the cycle time of the overall system is achieved.

The plant also impresses with its sustainable operation: In addition to the pretreatment plant, PURIMA has supplied a clean water recirculation plant, for the systematic treatment and reuse of water, and a physical-chemical wastewater treatment plant. The latter treats frequently used process water in such a way that, in accordance with legal standards, it can eventually be fed into the wastewater disposal system.

Moreover, due to the cooperative partnership between the customer and PURIMA, the plant was delivered on time. Thanks to the customer’s high level of flexibility and the close cooperation between the specialist departments, it was possible to procure missing electrical components globally from the customer’s worldwide locations. If this was not possible, suitable alternatives were worked out. Finally, the entire plant incl. outdoor logistics seamlessly integrated into the higher-level control of the entire factory.

Safety through fully automatic precision cleaning.

All in all, a pickling and passivation plant has been created that makes an important contribution to the further development of the customer and his business. More significant for the individual, however, is the safety ensured by the system in the context of the use of e-mobility. The pickling and passivation line scores with many well thought-out features, such as the ingenious fabric carrier concept, which automatically activates the appropriate program, or the multi-stage, automated treatment and drying process, which achieves the specified cycle times. The automatic and sensor-controlled media preparation, which supplies all process basins with content, complements the fully automatic pretreatment process. Where heat is needed in the process, PURIMA has integrated solutions by electric heating and hot water boilers. In this way, the plant is independent of fossil fuels. Overall, PURIMA can already look back on a wealth of experience in the field of e-mobility and has already implemented professional solutions in this forward-looking area for well-known companies in the industry.