The battery market has seen significant growth in recent years, driven by the increasing adoption of electric vehicles and stationary energy storage systems. To reduce the carbon footprint of electrochemical storages, it’s essential to maximize the usage of existing batteries by developing tools that improve their sizing, monitoring, and diagnostics.

RSE’s research focuses on the optimal management and extending the lifespan of electrochemical storage systems. This report outlines three interrelated research activities. The first one addresses the second-life and reutilization of healthy batteries after their initial use. The objective is to define a battery remaining life estimator for the entire battery life cycle, thus considering also this second phase.

Specifically, based on a semi-empirical aging model previously developed by RSE to estimate the battery State-of-Health in the initial phase of its lifecycle, a new model is being developed to simulate the degradation curve’s behaviour also during the second life phase.

Aging tests on NMC lithium-ion cells have been restarted to gather data on the degradation curve during this non-linear phase, which can be compared to the simulated results from the developed model. The second activity involves defining and developing tools for a digital twin of a battery system. To this end, equivalent battery electro-thermal models and aging models, along with SOC and SOH estimators, have been identified. Also, a preliminary investigation on suitable machine learning techniques to update these models have been carried out. Finally, a specific use case has been identified to test the digital twin, implementing, and validating the models and algorithms described in this report.

The third activity deals with developing advanced monitoring systems for battery. A testing procedure has been established to validate the accuracy and repeatability of measurements from a low-cost chip called CMU (Cell Management Unit) developed by Sensichips. The CMU performs various online measurements, including impedance spectroscopy, without the need for battery disconnection and therefore operation outage. The validation aims to assess the CMU’s performance under different operating conditions and technologies tested. The resulting spectroscopy measurement datasets and aging test outcomes will be imported into the laboratory’s test data database and made publicly available.

The Report is available on the Italian site