Entwicklung eines verteilten Energiemanagementsystems

Traction batteries define the selling price of electric vehicles and by that lead to less market acceptance of them. A traction battery is not only made of the energy storage itself but also of a monitoring device - the battery management system (BMS). The BMS is designed to ensure trouble-free and safe operation of the battery. Since BMS are developed individually for each vehicle, it is the objective of this thesis to find an approach of standardized BMS design and thus to provide a way of reducing costs of the battery. This work deals with the architecture of BMS and its balancing systems. It is shown that todays systems are inflexible and do not offer the possibility of a standardized BMS. Accordingly a new concept, the intelligent cell is developed, which is the basis for a standardized, scalable BMS. An intelligent cell consists of an energy storage and an electronic circuit. Intelligent cells form a battery without having a central controller. This means intelligent cells build up a distributed BMS. Inter alia, the functionality of the intelligent cell is achieved by power electronics, which controls the flow of energy and enables both, balancing and security. Intelligent cells communicate via Powerline Communication (PLC). The protocol for this communication is developed in consideration of the new architecture. It is shown that the principle of a distributed BMS is possible. Intelligent cells communicate with each other and provide the functionality of a BMS. The power electronics of the intelligent cell makes it possible still using the battery at its maximum performance with strongly aged or even damaged cells by excluding them from the compound. It is shown that this technology enhances the range of an electric vehicle by the optimal usage of the installed energy. Furthermore, the approach can prolong the lifetime of a traction battery overall. The developed prototype of the intelligent cell needs to be optimized to be market ready. If these optimizations are successful a BMS will be available that improves both, costs and lifetime of a traction battery