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Innovative regenerative on-board energy converters

Cost-efficient solutions for the reduction of range problems of electric vehicles on the basis of independent energy converter systems supplied with renewable energies. This project focuses on research into cost-efficient solutions for reducing operating range problems in electric vehicles. It involves the local provision of electric energy and heat through small-scale, self-sufficient energy converter systems (on-board charging systems), running on regenerative fuels consisting of either fuel cells or natural gas.


One of the main problems in electric vehicles is the energy needs of auxiliary consumers, such as the air conditioning system. In addition to the high cost of batteries, this is an obstacle to the rapid proliferation of electric vehicles. Electrical systems produce hardly any waste heat that could be used to heat the passenger compartment of a vehicle. Alternative, energy-conserving methods for heat management and in general for targeted control of the existing or required flow of energy in the vehicle must be found to increase the operating range of the vehicle and shorten charging times.

Goals and approach

One possible solution is to provide electric energy and heat through small-scale and self-sufficient energy converter systems (on-board charging systems) in the vehicle itself. In the InnoROBE project, a fuel cell system with a suitable DC/DC-converter and an internal combustion engine with generator and inverter is being studied. These can be run with regenerative fuels, such as methane for the internal combustion engine or hydrogen for the fuel cell. Newly developed heating concepts help increase operating range, shorten charging times, and reduce costs.


Innovations and prospects

Compared to purely battery-operated vehicles, on-board charging systems save additional costs, because a smaller battery design is possible. But the customer also profits from the longer operating range. This way the new system has the potential of accelerating the widespread market introduction of electric mobility.


Project profile

Group coordinator

  • GreenIng GmbH & Co. KG

Project period

  • 08/2012 – 07/2015

Project partners

  • GreenIng GmbH & Co. KG, Leutenbach
  • Robert Bosch GmbH, Stuttgart
  • Fraunhofer ICT, Karlsruhe
  • German Aerospace Center (DLR) - Institute of Vehicle Concepts, Stuttgart

Funded by the Federal Ministry of Education and Research (BMBF)