Novel application of differential thermal voltammetry as an in-depth state-of-health diagnosis method for lithium-ion batteries

Abstract

 Accelerated ageing of lithium-ion cells under various storage/loading conditions.  Degradation analysis was performed using various in-situ diagnosis methods.  Differential thermal voltammetry (DTV) suitable for electric vehicle application.  State-of-health estimation through quantitative analyses of DTV peak evolution. AUTHOR E-MAIL ADDRESSYu Merla -yu.merla09@imperial.ac.uk Billy Wu -billy.wu@imperial.ac.uk Vladimir Yufit -v.yufit@imperial.ac.uk Nigel P. Brandon -n.brandon@imperial.ac.uk Ricardo F. Martinez-Botas -r.botas@imperial.ac.uk Gregory J. Offer -gregory.offer@imperial.ac.uk ABSTRACT Understanding and tracking battery degradation mechanisms and adapting its operation have become a necessity in order to enhance battery durability. A novel use of differential thermal voltammetry (DTV) is presented as an in-situ state-of-health (SOH) estimator for lithium-ion batteries.Accelerated ageing experiments were carried on 5Ah commercial lithium-ion polymer cells operated and stored at different temperature and loading conditions. The cells were analysed regularly with various existing in-situ diagnosis methods and the novel DTV technique to determine their SOH. The diagnosis results were used collectively to elaborate the degradation mechanisms inside the cells. The DTV spectra were decoupled into individual peaks, which each represent particular phases in the negative and positive electrode combined. The peak parameters were used to quantitatively analyse the battery SOH. 2A different cell of the same chemistry with unknown degradation history was then analysed to explore how the cell degraded. The DTV technique was able to diagnose the cell degradation without relying on supporting results from other methods nor previous cycling data. KEYWORDS:

Extending battery life: A low-cost practical diagnostic technique for lithium-ion batteries

“…The results are comparable to the single cell test under natural convection carried out in our previous work [17]. This work also demonstrates the use of the technique under charge for the first time, and the use of heat flux measurement instead of temperature.…”

“…Peak fitting analysis of the results were carried out using peakfit.m script [22] in MATLAB where the differences in the peak parameters such as the peak position and width can give information on the cell's state-of-health [17,23]. Figure 3a and 3b demonstrates example peak fittings of DTV curves where each peak has been labelled accordingly for a combination of nickel-manganese-cobalt electrode phase (①-②) [24][25][26] and a graphitic carbon phase (❶-❺) [27].…”

“…The method of Differential thermal voltammetry (DTV) [16,17] was previously reported by the authors as a complimentary tool to incremental capacity analysis (ICA), showing how simple temperature measurements could be used to infer similar information. DTV only requires temperature and voltage measurements and is carried out by measuring the change in cell surface temperature during constant current discharge and does not require temperature to be carefully controlled.…”

Degradation Mechanism Detection for NMC Batteries based on Incremental Capacity Curves

“…They have been studied also for SoH estimation, like in NMC cells [18][19][20], LFP [21][22][23] and also composites NMC+LMO [23] cells.…”

Simulation and Measurement of the Current Density Distribution in Lithium-Ion Batteries by a Multi-Tab Cell Approach

“…Also non-properly adapted thermal conditioning can have a crucial impact on the performance of larger cells. [10][11][12] Modeling of internal distributions of potential and temperature along the electrodes is quite challenging, since even to calculate only a few cycles, a lot of computational resources are required for fully resolved models. In literature, there are many examples for spatially resolved multi-dimensional modeling approaches, 8,9,[13][14][15][16] which aim at representing the cell's internal behavior in terms of potential, current density, state of charge (SOC) and temperature distribution.…”