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D. Geringer, P. Hofmann, J Girard, W. Knefel et al.:
"Berücksichtigung der Batterie­alterung während der Auslegung eines 48-V-Mild-Hybrid-Antriebs­strangs | Consideration of battery aging during the powertrain design of a 48V-mild hybrid powertrain";
Talk: ATZ Live [Der Antrieb von Morgen 2021], Hanau bei Frankfurt am Main / Germany (invited); 2021-01-27 - 2021-01-28.

A promising and relatively cost-effective way to achieve lower CO2-fleet emissions is a widespread use of 48V-mild hybrid powertrains. These systems have an attractive cost to benefit ratio compared to full hybrid vehicles because they reach a significant fuel consumption reduction with only manageable modifications to existing conventional powertrains. A design goal for the additional 48V-battery is keeping its capacity small to save material costs, which results in high specific power requirements for it because of the resulting charge rates. Additionally, aging has also an important influence on the design of the battery especially in regard to the lifetime of automotive applications. Often the battery Capacity is oversized to cope with the capacity loss over time.
Having a good knowledge of the aging allows the battery to be designed better according to the lifetime expectations which results in a cost reduction potential.The battery aging is dependent on several operating and design parameters of the battery like the battery temperature, depth of discharge, and battery capacity among others. Previously conducted investigations on such automotive high-power lithium ion cells for mild hybrid systems led to many insights for these influence parameters regarding the battery temperature, state of charge, or charge rate, including simulation models for quantification of the effects.
In this presentation a model-based investigation of different powertrain design approaches to reduce the aging effects, the battery size, and the challenging mild hybrid operating parameters are shown in order to lower the battery costs. For example, the effects of different cooling systems or a simple reduction of the initial battery capacity are analyzed to describe their impact. Using these calculations, it is possible to compare the effects of various measures already in the design phase and a precise dimensioning can be carried out without large oversizing.