In particular, the first part of the project focused on building and implementing a customized setup that emulates the battery impedance ternary sequence measurements for a a small battery pack comprised of series connected cells. Onwards the project, this setup was used to monitor the impedance of selected battery cells which were subjected to aging in a separate battery cycler. It was verified that the impedance provides unique information about the health of the battery but also about the temperature. Moreover, it was shown that computationally light feature-based models may be sufficient to be applied in the algorithms but that data-driven methods would also benefit of the inclusion of the impedance.
Later on in the project, it was discovered that some of the applied ternary sequences have very unique properties that allow the sequences to be applied for non-steady-state system measurements. In the context of battery impedance measurements, this implies that the impedance can be measured while the battery is being used by the application, being highly beneficial in the real-time monitoring of the impedance. This, along with the briefly derived theoretical framework in why the sequences works as they do, can be considered as the main achievement of the whole project which can further facilitate the reaching of the objectives 2 and 3 of the project. However, the actual verification of the technology applicability in real BMS af a battery pack prototype and further validation of the obtained lifetime increase was something that was not possible in the project. This was because of lacking laboratory equipment that prevented lifetime tests with such a battery pack prototype. However, because of other findings regarding the mentioned discovery of real-time monitoring capabilities of specific ternary sequences, these objectives have actually better technological grounds in succeeding in future research activities. Moreover, surprising discovery in the project was that the impedance measurement technology and state monitoring concept is also applicable to hydrogen technology.
