Experimental results of on-board battery-ultracapacitor system for electric vehicle applications

Automotive drive systems, which use more than one type of energy source, are considered an important step towards low polluting emission and fuel economy. All over the world, the automotive industry is undertaking strategic initiatives to develop new technologies applied to these systems; high-efficiency, high-specific power electric motors., load-levelling devices, hydrogen and direct-methanol fuel cells. advanced batteries, direct injection Diesel and Otto cycle engines are carrying out tests to evaluate their ability to reduce emission and increase vehicular economy. The aim of these initiatives is to propose a framework for analysis, design and control of vehicles within different energy generators. The paper discusses electrochemical capacitors, called ultracapacitors, and tests one of these to evaluate its ability for automotive applications. The results of the tests, effected on an ANSALDOBREDA prototype, want to evidence device ability to store energy during braking operations and to boost on requirements, to limit battery intervention. Some considerations on ultracapacitors charge efficiency are also reported.