• Kaja Mona Kristensen
3. semester, Sustainable Energy Engineering, Master (Master Programme)
The climate crisis has an impact on almost every sector in our life, including the transportation sector. A positive trend of electric vehicles could be registered. With the increase of electric vehicles, also the amount of lithium-ion batteries increased. Studies showed that the batteries are not free from environmental pollution, which is why it is proposed to keep the batteries as long as possible in use. In the transportation sector, batteries are declared to be at end of life (EoL) when they reach 80 % remaining capacity. Even though those batteries are no longer used in a vehicle, they could be used in a stationary application – as a so-called second life application. To design a second life application, the state of health (SoH) of the battery, in other words, the remaining capacity needs to be known, among other parameters. Today, the SoH is estimated by the car manufacturer or calculated by the car mechanic. So far, there is no commercialised procedure to estimate the SoH in a standardised way. Therefore, it is worthwhile to develop a procedure to estimate the remaining capacity of not only one, but multiple battery cells in a fast but nonetheless accurate way. This is where this master thesis takes up. With an experimental study including aged lithium-titanate-oxide (LTO) battery cells, it was tested whether a well-known and validated SoH estimation method could also be applied on batteries that already reached 80 % remaining capacity. This thesis also discusses the feasibility of real application and the possibility of reducing the application time by reducing the measurement interval.
Publication date23 Dec 2020
Number of pages79
External collaboratorZurich University of Applied Sciences
Jürg Rohrer


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