Onboard Impedance Diagnostics Method of Li-ion Traction Batteries using Pseudo-Random Binary Sequence

Environmental and economic reasons have lead automotive companies towards the direction of EVs and HEVs. Stricter emission legislations along with the consumer needs for more cost-efficient and environmental friendly vehicles have increased immensely the amount of hybrid and electric vehicles available in the market. It is essential though for Li-ion batteries, the main propulsion force of EVs and HEVs, to be able to read the battery characteristics in a high accuracy manner, predict life expectancy and behaviour and act accordingly. The following thesis constitutes a concept study of a battery diagnostics method. The method is based on the notion of a pseudo-random binary signal used as the current input and from its voltage response, the impedance is used for the estimation of parameters such as the state of charge and more. The feasibility of the PRBS method at a battery cell has been examined through various tests, both in an experimental manner at the lab but also in a simulation manner. The method is compared for validation against the electrochemical impedance spectroscopy method which is being used as a reference. For both the experimental and the simulation examinations, the PRBS method has been validated and proven to work. No matter the change in the parameters of the system, the method behaves in a similar manner as in the reference EIS method. The level of detail in the research and the performed experiments is what makes the significance of the results of high importance. The method in all ways has been proven to work in the concept study and based on the findings, if implemented on an EV’s or HEV’s electric drive line and the same functionality is observed, be used as a diagnostics method of the battery of the vehicle

On-board impedance diagnostics method of Li-ion traction batteries using pseudo-random binary sequences. Method evaluation and feasibility study of concept.

This thesis deals with the on-board impedance measurements of Li-ion batteries on hybrid electric vehicles/electric vehicles by using pseudo-random binary sequences (PRBSs). The impedance of the battery can be related to its state of charge but the accurate impedance measurements are difficult to perform in the vehicles. By using an excitation signal like PRBS, it is possible to extract the impedance information of the battery packs. Both experiments and simulations are performed with different set-ups to verify the PRBS method. A non-parametric method is used to process the data and extract the impedance measurement. Experiments in the laboratory at different SOC levels and temperatures are made to validate the PRBS method. In the simulations, the noise sensitivity is analyzed. It is shown that the PRBS method can produce a valid electrochemical impedance spectrum in a limited frequency range, similar to the result from a high accuracy laboratory impedance analyzer. The method is stable at different SOC levels and temperatures. However, the battery impedance at high frequency is difficult to obtain with the PRBS method in the experiments. A simulation of the excitation signal in the vehicle is performed where the electric motor is used as the load. It shows that it is possible to some extent to use the drive line in a hybrid electric vehicle/electric vehicle to perform an on-board battery impedance measurement

INTA MOAT: a tool for governing the urban commons

In the historic city of Nicosia located on the island of Cyprus, the old city is enclosed by the Venetian walls. These were initially designed during the Venetian period on the island and later on, finished during the British Colonial period on Cyprus. Today the public space of the Moat and the Bastions are underused by citizens and visitors of the city. Most of the citizens of Nicosia nearly forgot the moat space due to the low public access and non-existence of social activities. Thus, lead to the leftover of the ‘bastions-moat-new city boundaries’ space as void. The INTA MOAT project proposes a platform to facilitate the use of the public space within the moat area at the old city’s Venetian walls, enabling a diverse set of activities and reconnection with this historical site