Lithium titanate battery cells with their excellent charge and discharge rate capabilities in combination with their long lifetime have become an attractive option for these kinds of applications. Today, battery electric vehicles as well as stationary battery system demand lithium-ion batteries. The results for one example use case show a cost-optimal battery system design with additional cells and partly redundant E/E components. The combination of stochastic failure analysis and aging mechanisms forms the basis for an overall battery design optimization with a genetic algorithm. This framework offers considerable advantages for modeling of complex non-linear dependencies as, e.g., for capacity degradation. A generic and behavioral battery model describing the dependencies between single elements is proposed, which is then further used for reliability evaluation by means of Monte Carlo simulation. This paper investigates a systematic approach for the reliability estimation and optimization of fail-operational battery systems. It is thus important to quantitatively evaluate the system design in terms of performance degradation and cost already in an early phase. Moreover, a battery design limiting the capacity degradation over the lifetime to a specified minimum can reduce the overall maintenance cost. To let the vehicle automatically drive to a safe state in case of a fault, a minimum battery performance in terms of remaining energy, output voltage and power is required. This requires new design concepts for an electrical powertrain and its subsystems including the traction battery system. Starting with highly automated driving (SAE Level 4), human intervention is not required anymore and therefore the requirements on fail-operability of safety-critical subsystems increase in order to maintain the safety of the vehicle and the passengers. The characteristics of the proposed antifuse device make it also an ideal power electronic device for bypassing faulty series connected sub-systems used in high-availability applications or fail-operational redundant systems.īesides the driving functions, powertrain electrification and design is an important task in development of automated driving. This paper shows how the integration of antifuse devices in battery cells can be used to bypass and turn-off lithium-ion battery cells thus improving the safety and availability of battery systems used in transport applications like aircraft, railways, ship and road vehicles. The activation time corresponding to the delay between the reception of the electrical trigger signal and the full conduction of the antifuse is less than 10 ms even at environment temperatures below -40☌. After having been activated, the same antifuse device becomes a bidirectional bypass element offering less than 20 micro-ohms of resistance to the electric current. A pristine antifuse device provides an electric resistance of more than 100 mega-ohms between the terminals. The antifuse is a scalable power electronic device of 1 cm² of active area. This paper presents a new power electronic device, named power antifuse, providing an irreversible bypassing function for the current after having been ignited by an external electrical signal.
0 Comments
Leave a Reply. |