Hybrid power supply for municipal vehicles
Which electricity storage system will be used in future to drive and work electric municipal vehicles? The scientists in the ELAAN project are testing this and are combining the advantages of batteries with those of a fuel cell range extender. They are testing the concept on a demonstration vehicle with previously developed components that include the battery module, fuel cell subsystem, electric motor and associated power electronics. The demo vehicle is scheduled to be completed in spring 2017.
|Project status||Development of the sub-modules and vehicle integration|
|Project duration||October 2013 until June 2017|
Municipal utility and work vehicles for logistics, horticulture, road construction as well as waste disposal, clearing and street cleaning services pose considerable dynamic power requirements for the drive during the driving operation. In order to electrically operate such vehicles, the power storage system must be efficient, durable and quickly rechargeable. In the ELAAN project (Electric drive train for work and commercial vehicles), the scientists are combining a battery system with a fuel cell that acts as an emission-free range extender. The researchers are integrating the innovative drive system into the drive platform of a type T-1250 LADOG commercial vehicle. This shall be used to gain experience during everyday operations until the end of the project.
The decisive advantages of electric drives include their local zero emission and the significantly lower noise emission. Especially municipal vehicles are driven and used in city centres, including in pedestrian zones. Here the regulatory provisions are becoming increasingly stringent, which means that appropriate systems are required, as are being developed in ELAAN. The range extender, battery, power electronics and motor are being designed and simulated based on the typical load profiles for utility and work vehicles, and are being optimised during operation. It is intended to standardise the electrical and mechanical interfaces taking existing standards into account.
The system is planned to enable a refuelling time of less than three minutes and be more compact and lighter than a purely battery-powered power supply. At the same time, the service life, performance and operating range are intended to correspond to that of a conventionally operated vehicle. The detailed analysis of the load requirement profile for dimensioning the individual components resulted in an engine power of 60 kW, a fuel cell power of 20 kW and a nominal battery capacity of around 5 kWh.
Industry, SMEs and science involved
The drive system is being developed by the medium-sized industrial companies ElringKlinger, Heinzmann and LADOG Fahrzeugbau. The Fraunhofer Institute for Solar Energy Systems ISE is providing the scientific support. The future vehicle integration is being realised by LADOG and the project partners ElringKlinger and Heinzmann are supplying the engine, fuel cell and battery pack as the value-adding components. As an associated partner, Fronius International is designing the fuel cell system and the power electronics for electrical integration in the LADOG vehicle.
A transferable model is being developed
Optimum tuning of the electric motor including the inverter, battery and range extender with simultaneous decoupling of the traction and hydraulic drive is intended to further exploit the efficiency potential than was previously realised in projects. The optimisation shall be enabled by means of a model-based design that describes the essential elements of the drive system. The model will be able to simulate the optimal constellation of a modular drive unit for any application and determine an efficient operating strategy.
- LADOG is the project partner for integrating the electric drive within the entire drive train as well as for integrating the subsystems within the vehicle.
- ElringKlinger is developing the battery and fuel cell modules taking into account both the application specifications, such as typical load profiles and cold starts, and the installation situation.
- Heinzmann is developing the electric motor and is selecting and adapting suitable motor controllers.
- On the research side, Fraunhofer ISE is supporting the two different battery and fuel cell development areas.
- Fronius International is developing the power electronics and control system for the fuel cell range extender and is carrying out the system integration of the fuel cell, battery and hydrogen storage unit.