Analysis of Impedance Spectra of Aged Commercial LTO Cells

The impedance spectra of aged commercial LTO cells have been fitted with an equivalent circuit model. The model contains an inductive part, a constant phase element and resistance for the charge transfer process and a Warburg element and addition RC-element for the slower frequency tail. The serial resistance, charge transfer resistance and Warburg coefficient rise […]

Model-based characterization for silicon-carbon blended electrodes

In recent research for the design of better performing lithium-ion batteries, blended electrodes have started gaining relevance, combining beneficial characteristics of different materials. As an example, silicon graphite anodes are good candidates to increase the energy density of lithium-ion batteries. The complexity of transport phenomena increases in blended electrodes and therefore accurate modelling and characterization […]

Verification and Validation of Thermal Models for Li-ion Pouch Cells

Temperature has significant impact on the dynamic performance, operating limits as well as aging phenomena of Li-ion battery cells. Due to the complex and often limiting heat transport paths and the uneven heat release within the cell core, the inner temperature distribution can be highly inhomogeneous. At the same time, it is challenging to gain […]

Decay of Open Circuit Voltage during Storage of Lithium Ion Batteries

Calendaric ageing of lithium-ion battery (LIB) is relevant to most applications of LIB. Classical testing methods, which involve long-term storage with regular check-up (CU) are slow and cost intensive. New methods have been presented in the past, such as float current measurement [1] or the high precision coulometry (HPC) [2]. With these methods, the calendaric […]

Identification of Degradation Mechanisms for Lithium Titanate Oxide based Cells

The cyclic and calendar aging of in total 43 same-typed prismatic LTO cells are investigated. Therefore, measurements over a period of more than 600 days were carried out. Regarding the calendar aging, 19 cells were stored at 8 different operating conditions, under variation of state of charge and temperature. Considering the cyclic aging, 24 cells […]

Anode-Controlled Fast Charging Optimization of Lithium Ion Batteries

Electric vehicles are an important element for a sustainable environmentally and climate-friendly mobility. But charging of these takes considerably more time than refueling of a conventional one. This can be an obstacle for many consumers. For an increased acceptance of electric vehicles, the general objective is to charge the battery up to 80% SoC in […]

State estimation for fast charging applications of lithium-ion batteries

The use of reduced-order electrochemical models creates opportunities for battery management systems to control the battery behavior by monitoring the internal states in electrochemical processes, which are critical for safety enhancement and degradation mitigation. This poster explores a state observer for lithium-ion batteries based on an extended single-particle model, which results in a trade-off between […]