Cell-holder in AM by CRP Technology for electric motorcyclesERT

The Italian CRP Technology has produced with 3D printing a cell pouch frame for Energica Motor Company, to test on electric vehicles battery pack prototypes both for racing and production series.

Both born from the entrepreneurial vision of Cevolini family, the two companies started collaborating since the foundation of Energica, which is closely involved in the MotoE racing series and is the only firm in the world to have an exclusive testing ground to try new challenging technical solutions, for some of the best riders worldwide. Energica supersport electric motorcycles use a high-energy lithium polymer (Li-NMC) battery. The battery is contained in a sealed housing, with battery cells, the battery management system (BMS) and all the necessary systems to ensure the safety of the vehicle.

The company asked CRP Technology to develop a special cell frame to test a battery pack prototype on the road, and the casing of each pouch cell had to be manufactured using a high-performance material, ensuring excellent mechanical properties and using advanced technology to meet Energica’s requirements. In order to carry out the tests, the team of engineers at Energica decided to provide each pouch cell with a surrounding case, with the function of support and reinforcement.

Following the examination of Energica’s needs and the analysis of the 3D files of the application, CRP Technology has opted to use selective laser sintering technology with Windform FR2, the new material from Windform TOP-Line family of high performance composite material for additive manufacturing, which is flame retardant and glass-fiber reinforced. The polyamide-based material, electrically insulated, stiff, resistant to temperature and  flame retardant, has fully satisfied all the functional requirements of the pouch cells casing. In particular, Windform FR2 guarantees self-extinguishing in case of operating anomalies, which are a result of a temporary voltage peak with consequent localized melting, followed by combustion initiation.

Also very important is the stiffness of the material, essential in this application in order to withstand the volumetric expansion that cells undergo during the charge and discharge cycles, maintaining each cell in its position within the battery pack without moving and also withstanding the stresses caused by the pressure generated by the expansion. The 3D printed cell casings in Windform FR2 allow a certain degree of freedom of movement, to swell and contract without deforming, without going out of position, therefore without interfering with one another.

Finally, a heat rejection metal plate with two lateral structures has been attached to each pouch cell and holder, achieving a cooling function: the heat is transferred to the lateral structures and dissipated outside, in combination with the cooling system patented by Energica which employs specific ventilation paths that limit the stress on the batteries. Once again, tests have proven that Windform FR2 glass-fiber reinforced and flame-retardant composite material maintains required stiffness, and does not deform with the increase of heat, thanks to the fact that Windform FR2 deflection temperature under load is higher than any other non-composite material with the same flame-retardant characteristics.