In recent years, the number of electrochemical storage systems sold and used for stationary and vehicular applications has been growing rapidly. Their use allows for a more efficient and safe use of energy from non-programmable renewable sources.

Since storage systems are becoming more widespread while the market-available tools for their management still have important shortcomings, it is necessary to develop new diagnostic algorithms and battery charge/discharge management systems that allow the non-homogeneity between cells to be controlled in an efficient and cost-effective way. This report describes the research activities carried out on three different topics related to storage system management.

The first topic concerns battery diagnostics. Market-available diagnostic tools for estimating the state of charge and health of the battery have a good accuracy when the battery is new. However, their accuracy decreases over time as the battery degrades and its performance changes. This is mainly due to the lack of updating of the estimator parameters. The report analyses the solutions proposed in the literature to solve the problems of performance degradation of state of charge estimators during the battery life. After an accurate bibliographic search, the approach to follow to realise an estimator with self-learning capabilities that does not require characterisation tests was defined.

The second topic is the how to reuse veihcle batteries that are no longer suitable for vehicle applications. The aim of the activity is to obtain a storage system demonstrator that exploits the concept of the 2nd life battery. The report describes the design choices made for the creation of the demonstrator.

The last research topic concerns the hardware that manages battery charging/discharging. This function is usually performed by the battery management system (BMS). The report describes the technical analysis performed on a modular multi-level converter that allows one to manage the battery by integrating the BMS and the storage system inverter into a single component. Furthermore, the test procedure used to start tests on lithium-ion cells is described in order to verify the impact of the control strategy on battery life.