It’s small, quiet – and defining the future of electro-mobility: The Rheinmetall Electric Mobility Vehicle (EMove) is a testbed packed with alternative drive technology components. Rheinmetall Automotive has now unveiled the new vehicle – based on a Fiat 500. Among other things, the car features a battery pack developed in cooperation with external partners as well as a powerful traction engine. Without impinging on the useful space in the trunk and passenger compartments any more than the conventionally powered series model, the EMove reaches a top speed of 135 km/h and a maximum range of around 250 kilometers on a single battery charge. In a metaphoric sense, though, the vehicle’s range is far greater: The current configuration could already serve as the basis of a possible series concept; at the same time, the system approach is so flexible that it lends itself to other applications as well, responding flexibly to customer requirements.
Battery in the underbody
The battery concept in the Fiat 500 rests on the premise that most electric and hybrid vehicle will be equipped with underbody batteries.
Dr. Peter Seggewiß, Vice President New Propulsion Technologies at Rheinmetall Automotive, knows the advantages of this solution: “Underbody batteries impinge only slightly on load capacity, don’t shift the vehicle’s center of gravity upward, and can be integrated into the supporting vehicle structure.” The 29 kWh -lithium-ion battery is modular in design, enabling flexible, customer-specific solutions. To make sure the component is the right answer for as many manufacturers as possible, the different battery cell types can be integrated and thermally conditioned. The basic framework consists of a structurally optimized cast aluminum frame with cooling ducts built into the bottom plate. Moreover, because the battery contains no liquid medium, the design adds to the overall safety of the vehicle.
Guided by a systematically lightweight design principle, the development engineers produced a battery pack with an excellent specific energy density-to-weight ratio. Together, the eight identical modules and the pack structure weigh 180 kg. With an eye to steadily perfecting the battery, Rheinmetall Automotive has set up its first in-house battery testbed, where battery cells of various types are measured and tested.
Partnership for protection
The energy storage unit is mounted in a crash-proof part of the vehicle. Since the battery is located in the underbody, its underside is of course unprotected. This could result in a short circuit and subsequent battery fire if, for example, the battery cell was mechanically damaged by a piece of metal hurled up from the road surface at high velocity. To prevent this from happening, Rheinmetall Automotive and Rheinmetall Chempro GmbH (a subsidiary of Rheinmetall Defence) joined forces to develop a protective shield. “The underbody shield consists of a stress-adapted fiber composite structure (CFK/AFK), which we subjected to extensive impact testing and numerical analysis”, explains -Seggewiß. “Weighing just 14 kilograms, the shield is about 56 % lighter than a comparable aluminum structure.” The underbody armor offers protection against blunt and sharp objects at velocities of up to 150 km/h, and also protects the bottom plate of the battery against the static load when the vehicle is set down. Moreover, the flame-retardant characteristics of the fiber-composite battery pack lid protect the passenger compartment from the high temperatures resulting from a battery fire. Designed to resist fire for over fifteen minutes, this assures an adequate evacuation time. The lid of the battery pack meets the high thermal resistance requirements due to the low heat conductivity of the material, the use of a highly flame-retardant plastic matrix, and application of a thermal protective coating to the inside of the battery lid. In this project, Rheinmetall Chempro GmbH was able to draw on its longstanding expertise in the field of ballistic vehicle protection and fiber composites. A compelling concept: The battery protection design took third place in the Institute for Individual Producers (ife) “Losgröße 1+” Innovation Prize contest.
A 90-kW engine
Besides the battery pack and underbody protection, the traction engine plays a central role in Rheinmetall Automotive’s demonstrator vehicle. It is a 3-phase, permanent magnet synchronous motor of the kind used in BMW i3 and Hyundai IONIQ Elektro, with an output of 90 kW. The fully electric Fiat 500’s drive system is based on an energy content of 29 kWh. The system configuration incorporates active cooling that extends not just to the engine itself, but also to the adjacent power electronics. “The electromobility testbed is a central platform that lets us expand our product portfolio for electrification of the drive train in a carefully targeted, drivable way,” explains Heinrich Dismon, CTO Rheinmetall Automotive and project’s initiator. The plan calls for integrating many more components. This way, Rheinmetall Automotive will be able to continue pressing ahead with innovative new mobility concepts, helping to shape a more environmentally friendly future.
Technical data of the EMove
Mini (Triple 0 segment)
|Weight, empty||1,350 kg|
Permanen magnet synchronous motor
135 km/h (capped)
Energy consumption, electric
9,5 kWh per 100 km
Nominal range, electric
approx. 250 km
|Dimensions (L x B x H)||1.500 x 750 x 208 mm|
|Dimensions (L x B x H)||371 x 310 x 110 mm|