A quick on-line state of health estimation method for Li-ion battery with incremental capacity curves processed by Gaussian filter

• Published in: Journal of power sources 2018-01, Vol.373, p.40-53
• Main Authors: Li, Yi, Abdel-Monem, Mohamed, Gopalakrishnan, Rahul, Berecibar, Maitane, Nanini-Maury, Elise, Omar, Noshin, van den Bossche, Peter, Van Mierlo, Joeri
• Format: Article
• Language: English
• Subjects: Ageing mechanism; Differential voltage; Gaussian smoothing; High energy NMC batteries; Incremental capacity; On-line SoH estimation
• ISSN: 0378-7753; 1873-2755
• DOI: 10.1016/j.jpowsour.2017.10.092

This paper proposes an advanced state of health (SoH) estimation method for high energy NMC lithium-ion batteries based on the incremental capacity (IC) analysis. IC curves are used due to their ability of detect and quantify battery degradation mechanism. A simple and robust smoothing method is proposed based on Gaussian filter to reduce the noise on IC curves, the signatures associated with battery ageing can therefore be accurately identified. A linear regression relationship is found between the battery capacity with the positions of features of interest (FOIs) on IC curves. Results show that the developed SoH estimation function from one single battery cell is able to evaluate the SoH of other batteries cycled under different cycling depth with less than 2.5% maximum errors, which proves the robustness of the proposed method on SoH estimation. With this technique, partial charging voltage curves can be used for SoH estimation and the testing time can be therefore largely reduced. This method shows great potential to be applied in reality, as it only requires static charging curves and can be easily implemented in battery management system (BMS). •Proposed an on-line battery state of health (SoH) monitoring method for NMC cells.•The method can monitor battery SoH with partial charging data.•Ageing mechanisms of batteries are studied by non-destructive methods.•Gaussian filter is used to obtain IC curves with improved smoothness.•Established a quantitative correlation between features on IC curves and cell SoH.