Starting next year, automobile manufacturers and suppliers will also be able to use the Frecc0  for testing new components. The basis of the demo model is the new Artega GT manufactured by Artega Automobil GmbH. 

The establishment of the Frecc0 platform, abbreviation for "Fraunhofer e-concept car Type 0" currently under construction, will serve as a scientific integration platform and demonstrate the system competency of Fraunhofer institutes.

"We are working on all angles of electromobility: designs, system integration, energy generation and distribution, storage technologies and a whole lot more. The expertise is uniquely available at the Fraunhofer-Gesellschaft and bundled into our consortium 'Fraunhofer System Research on Electromobility,'" as (left) Professor Ulrich Buller, Senior VP for Research Planning, points out.

The goal of the Fraunhofer researchers is to develop prototypes for hybrid and electric vehicles, in order to support the German automotive industry as it makes the crossover to electromobility. The federal ministry for education and research BMBF is funding these plans with a total of €44m from Economic Stimulus Programs I and II.

Automobile manufacturers and suppliers can also use the "Frecc0" to test new components jointly with the Fraunhofer institutes starting in 2011. The basis is an existing car, an ideal platform for the integration of Fraunhofer components.

For example, researchers can test how a crash-proof battery system, a wheel hub motor and a battery charger behave in the car as a (left)  total system.

Networked research on the battery system
Experts from 11 Fraunhofer institutes are currently working on the battery system, no easy task, because the batteries and electrical systems in the vehicle are subject to the toughest standards.

(Left) Energy generation and distribution, and storage technologies

They must be safe, durable and efficient. The driver must be able to tell at any time how much farther he can get before the battery needs a recharge. He also needs to know about traffic hold-ups so that, if necessary, he has enough time to find a service station.

Where it is easy to determine the filling level of a gas-powered vehicle, this is not so easy with the battery of an electric car. A lithium-ion battery system mostly consists of several hundred cells. They do not always run down at an equal pace. But if isolated cells break down or no longer delivers the intended capacity, the entire battery may be affected.

To counter these problems, elaborate, cross-networked battery management systems are used, as well as a higher-level energy management system. Researchers are developing such a system, which until now, only existed in prototypes – and for stationary battery systems, at that.

Project manager Dr. Matthias Vetter  (right) of the Fraunhofer Institute for Solar Energy Systems ISE in Freiburg, who is coordinating the plan, explains the basic principle. "Within fractions of seconds, the electronics measure the line-to-line current, the single cell voltage and the temperature of each cell, and from this determine their state of charge and state of health. This way, a determination can be made for each cell on the threat of overload, excessive discharge, overheating or premature aging."

A challenge that scientists face is being able to determine reliable values during continuous operation. For the most part, the data cannot be captured here in the quality required. One has to draw conclusions regarding the actual measured values and internal conditions – like state of charge and state of health – based on defective measurements.

Vetter explains this complex car battery system. "It contains two strings, each with eight modules of twelve cells. For controlling, a total of 16 interlinked battery management systems are used. They communicate with an energy management system integrated into the battery pack via a databus, widely used in the auto industry – a Controller Area Network (CAN). For example, the system can equalise differing charge statuses of the cells, and thus always provide maximum capacity and energy. At the same time, it can also issue forecasts."

Electronics also measure onward and reverse flow temperatures of the attached cooling circuit. While the pump should ensure no overheating occurs, it should also consume as little energy as possible itself. To do so, the system also controls the cooling circuit by a model-based regulator, optimising energy consumption, lowering peak temperatures, and increasing reliability.

Simultaneously the system takes over communication with the vehicle. It submits forecast reports on distances and threshold values, both for drive control as well as for charging operations. It monitors itself to determine if the desired power violates critical current and voltage limits. At any time, the driver can read from the instrument panel how far he needs to drive until the battery has to be recharged.

Even in an accident, the system takes precautions: Through its circuit breaker, the higher level energy management is capable of shutting down the battery, either in its entirety, or just line-by-line. This could be necessary if individual cells overheat, suffer an internal short circuit or are completely dead.

And afeguards must be taken to make sure the car's body is not exposed to any live voltage, so that emergency rescue squads can open the car without risk. This is guaranteed by the appropriate sensors.

Scientists bring in expertise – from battery system design to safety tests; and from connection technology to recycling. Shared efforts accelerates research projects and moves results more quickly to market-ready conditions.

Wheel hub motors next
Wheel hub motors were invented in the 19th century. Ferdinand Porsche used these motors to equip his »Lohner Porsche« for the 1900 World Fair in Paris. Much has been done since then and prospects look good for wheel hub motors to successfully become the accepted drive concept for electric vehicles.

Fraunhofer researchers are engineering these motors, which are integrated into the car's wheels. In order to make electric cars a part of everyday life, new vehicle designs and parts are needed.

One advantages of wheel hub motors is that manufacturers can dispense with the conventional engine bay, space under the hood or bonnet, since motors are attached directly to the vehicle wheels. This opens up a wealth of car designer opportunities when drafting the vehicle layout.

An additional advantage is by dispensing with the transmission and differential, the mechanical transmission elements suffer no losses or wear and tear. Moreover, the direct drive on each individual wheel may improve the drive dynamic and drive safety.

"We are developing a wheel hub motor that integrates all essential electric and electronic components, especially the power electronics and electronic control systems, into the installation space of the motor.

"Thus, no external electronics are necessary and the number and scope of the feed lines can be minimised. There is a marked increase in power compared to the wheel hub motors currently available on the market.

Moreover, there is an innovative security and redundancy concept, which guarantees drive safety – even if the system breaks down," explains Professor Matthias Busse, (right) head of the Fraunhofer Institute for Manufacturing Engineering and Applied Materials Research IFAM.

Beside IFAM, researchers from the Fraunhofer Institute for Integrated Systems and Device Technology IISB, for Mechanics of Materials IWM and for Structural Durability and System Reliability LBF are tackling these issues.

Critics find fault with the negative effects of wheel hub motors on vehicle handling. Dr. Hermann Pleteit, IFM project manager, responds saying that the motor is extremely compact. "The high power and torque densities merely cause a relatively low increase in unsprung mass. But by configuring the chassis in different ways – like the muffler settings, for example - you can compensate for these effects. There is no impact on drive comfort."

The researchers are meeting yet another challenge and in contrast to conventional vehicles, electric cars can recapture the energy that comes from braking, feeding it back to the battery, experts refer to it as "recuperative." Now they work on maximising this energy recapture for the  future. Conventional braking systems still in use will only be needed in emergency situations.