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EU-funded ‘HyHEELS’ takes new approach to fuel cells

The HyHEELS project (Hybrid high-energy electrical storage) is developing an ‘UltraCap’ energy storage system that is suitable for hybrid and fuel cell automotive applications. Partners say HyHEELs is an important step in the drive towards ‘well to wheel’ energy efficiency.

Road traffic © Peter Gutierrez
© Peter Gutierrez

While the wide-scale deployment of fuel-cell-powered cars in the European fleet is still expected to constitute a process of decades, the problem of CO 2 emissions is here and now. The auto industry is therefore looking for solutions with both long-term potential, in terms of innovative power trains, and also with possible short term benefits in combination with current state-of-the-art technologies.

“The overall goal of HyHEELS is to provide an UltraCap energy storage system for the use in hybrid and fuel-cell-powered vehicles,” explains Rainer Knorr of Siemens VDO Automotive AG.

An ultra-capacitor or UltraCap, he explains, is basically an electrochemical double-layer capacitor, consisting of two electrodes immersed in an electrolyte. The high energy content of UltraCaps, in comparison to conventional capacitors, originates in the activated carbon electrode material, which has an extremely high specific surface area, and the short distance between the opposite charges of the capacitors. “Fundamental property differences between UltraCap and battery technologies result in long shelf life, extended useful life, high cycle life and a maintenance-free product,” he says.

No time to waste

HyHEELS development work entails the optimisation of the electrical properties of the basic capacitor and its integration into scalable modules, with integrated power balancing within the modules, power prediction and a communication interface with the drive train.

The work programme consists of two technical packages for the development of the UltraCap modules and an UltraCap controller, and a third package concentrating on simulation and modelling as well as on testing and evaluation of the developed hardware.

“Our UltraCap modules must be suitable for automotive application,” insists Knorr. “They will be fitted with a controller and subsequently tested and evaluated in a real vehicle environment. The UltraCap controller will ensure the reliable operation of the module, covering an expected lifetime of over 10 years.” Finally, he says, environment impact will be reviewed and road testing undertaken with several types of existing hybrid vehicles.

Strong co-operative partnership

The HyHEELS project was launched in November 2005 and includes important research partners from Germany, France, Belgium, Sweden, Poland, Italy and Switzerland. Knorr says investigations are running smoothly and have been fruitful. “In total, he says, “we have seen a good start to the project, and there is a common positive spirit within the consortium.

“Given the technological challenges to be mastered, we chose to co-operate within the framework of an EU-funded Specific Targeted Research Project (STREP), because we think this provides an ideal vehicle for the main European players in this area to undertake a common research and development programme.“

Ultimately, the results of HyHEELS, he says, cannot be regarded in isolation but have to be seen in the context of the vehicle for which it delivers the energy supply.

EU officials say a new EU-funded project, ILHYPOS (Ionic liquid-based hybrid power supercapacitors), presented at the recent TRA conference in Göteborg, Sweden, is now looking at the next generation of similar devices and is expected to deliver additional improvements in performance.