Drees et al. used a reference electrode to investigate the impact of the reference electrode location inside pouch cells on negative electrodes. The voltage of negative and positive were measured and the results validate the lithium-plating occurs when the negative electrode potential is less than 0 V . 2.2. Impedance
Real-time monitoring of NE potential is highly desirable for improving battery performance and safety, as it can prevent lithium plating which occurs when the NE potential drops below a threshold value. This paper proposes an easy-to-implement framework for real-time estimation of the NE potential of LIBs.
The mainstream LIBs with graphite negative electrode (NE) are particularly vulnerable to lithium plating due to the low NE potential, especially under fast charging conditions. Real-time monitoring of the NE potential is a significant step towards preventing lithium plating and prolonging battery life.
The dynamics of the battery's per-electrode potential can be described by an electrochemical model, such as the pseudo-2D or single particle model , , which enable the application of a state observer or a controller for real-time estimation and control of the physical states inside the battery .
To test the electrochemical impedance of battery cathode and anode, the reference electrodes is commonly used to obtain accurate and stable EIS data of two electrodes inside batteries . In Ref. , a gold wire reference electrode is used for impedance spectra measurement in LIBs.
Due to the difficulty of embedding a reference electrode inside the battery in practical applications, the model and estimation algorithms proposed in this paper have to be parametrised offline, which makes it difficult to capture the battery parameters varying over time due to ageing.