26 motor, it is capable of more. Regarding battery safety, the team has developed a unique carrier frame that not only helps to set the safe mounting and damping points for the battery previously discussed, but, in case of a thermal event, it contains pipes that guide potentially harmful gases out of the boat. The gases exit at the sides of the hull, where there is no passenger seating, and they are angled to stop water ingressing back up into the pipes. “In cars, you can just mount the packs at the undercarriage, so offgassing starts outside the passenger compartment, but electric boats could suffer a dangerous pressure build-up of gases if you don’t design this kind of venting system,” says Helmberger. As discussed with Scania’s Tony Persson (EME 23, January/February 2024), the battery packs in the nextgen Macan powertrain use prismatic Li-ion cells, which, for the Porsche cars, and hence the eFantom, contain an 8:1:1 ratio of nickel versus manganese versus cobalt. This contributes to energy density, as well as the charging capacity of the battery: DC fast charging at 250 kW can be used, enabling the pack to be replenished from 10% to 80% SoC in times estimated as less than 30 minutes, depending on various factors. The aforementioned Integrated Power Box is a patent-pending invention, designed to reduce cabling and weight (and hence cost) in the powertrain by combining the 11 kW onboard AC charger, a HV PTC heater and the DC/DC converter (which converts the battery’s 800 V output to a 12 V bus for cabin systems and other items in the low-voltage network). The PTC heater is not programmed for use in the eFantom as customers will essentially never take their yachts out in extremely cold temperatures, but the team opted not to remove it as they wanted as many unaltered components from the Macan as possible. The Integrated Power Box uses a CCS2 socket for use of both AC and DC charging in a combined connector input. This provides simplicity for the customer as it facilitates the use of almost any sort of charger plug. It also helps reduce excess complexity in determining where the engineers would need to deliver coolant in the thermal management system. Thermal management As discussed, an active liquid cooling system thermally manages numerous powertrain components. It functions using two coolant pumps, each one driving a separate water-glycol channel; one of those runs in the motor and inverter, while the other runs in the battery pack and the Integrated The eFantom’s heat exchangers are cooled by water pumped via the stern, so that heat dissipation doesn’t halt when the boat is planing March/April 2024 | E-Mobility Engineering
RkJQdWJsaXNoZXIy MjI2Mzk4