Effects of High Acceleration Mechanical Shocks on 94 Ah Large Format Lithium-Ion Battery Cells
In regular operation and especially in the case of crashes, lithium-ion batteries have to withstand severe mechanical shock loads. To ensure their safety, they are tested according to various norms and regulations with procedures depending on the country of usage, the field of the application and the mass of the cell. As there are only […]
Electrical and structural characterization of large-format lithium iron phosphate cells used in home-storage systems
Installed energy capacity of home storage systems, which is used to store excess energy produced by renewable sources, mainly photovoltaic (PV), has expanded rapidly in Germany in last years. Lithium ion batteries make up for more than 95 % of the new installations [1]. Home storage systems are typically constructed as a battery stack consisting […]
High duty use and fast charging of power tool battery packs: A simulation based study to improve cooling strategies
In the fast growing, but also highly competitive market of battery-powered power tools short charging times are essential to achieve a high customer acceptance. To prevent loss of performance and rapid charging capability due to cell aging the knowledge of proper use conditions in everyday practice is important. In this study, we will present a […]
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 […]