scholarly journals Quantitative Estimation of Turning Point of Ageing Based on a Two-Stage Model for Lithium-Ion Batteries

Haichao Lv ◽  
Xiankun Huang ◽  
Lixia Kang ◽  
Yongzhong Liu

Abstract The capacity fading of lithium-ion batteries (LIBs) is reported by a linear dependency followed by a nonlinear ageing process, where the former is dominated by solid electrolyte interphase formation and reformation (SEI and SEI-re), while the latter is by lithium plating. In this work, a two-stage model is developed to quantitatively predict the turning point during the capacity fading of LIBs, which couples the electrochemical and thermal models accounting for SEI, SEI-re and lithium plating. Accordingly, a quantitative evaluation method of the turning point is proposed by attributing the transition of the capacity fading to the balance of consumption of active lithium for SEI growth and lithium plating per cycle in the two stages. The characteristics of capacity fading of LIBs are quantitatively analyzed under various operation conditions and design parameters. An NCM111/graphite battery is used to validate the proposed model. The results shows the validity of the proposed model. The turning points of the capacity fading processes are influenced by operation and design parameters of LIBs, where lithium plating or SEI growth reign. According to the effect on the turning point, the order of significance of the factors are charging current, charging cut-off voltage, temperature and N/P ratio, respectively.

Modelling ◽  
2021 ◽  
Vol 2 (2) ◽  
pp. 259-287
Robert Franke-Lang ◽  
Julia Kowal

The electrification of the powertrain requires enhanced performance of lithium-ion batteries, mainly in terms of energy and power density. They can be improved by optimising the positive electrode, i.e., by changing their size, composition or morphology. Thick electrodes increase the gravimetric energy density but generally have an inefficient performance. This work presents a 2D modelling approach for better understanding the design parameters of a thick LiFePO4 electrode based on the P2D model and discusses it with common literature values. With a superior macrostructure providing a vertical transport channel for lithium ions, a simple approach could be developed to find the best electrode structure in terms of macro- and microstructure for currents up to 4C. The thicker the electrode, the more important are the direct and valid transport paths within the entire porous electrode structure. On a smaller scale, particle size, binder content, porosity and tortuosity were identified as very impactful parameters, and they can all be attributed to the microstructure. Both in modelling and electrode optimisation of lithium-ion batteries, knowledge of the real microstructure is essential as the cross-validation of a cellular and lamellar freeze-casted electrode has shown. A procedure was presented that uses the parametric study when few model parameters are known.

2015 ◽  
Vol 89 (5) ◽  
pp. 894-897 ◽  
Liu-Qun Zheng ◽  
Shu-Jun Li ◽  
Deng-Feng Zhang ◽  
Hai-Jun Lin ◽  
Yan-Yue Miao ◽  

2013 ◽  
Vol 32 ◽  
pp. 31-34 ◽  
Xingcheng Xiao ◽  
Dongjoon Ahn ◽  
Zhongyi Liu ◽  
Jung-Hyun Kim ◽  
Peng Lu

Rebeka Raff ◽  
Velimir Golub ◽  
Jurica Perko

The aim of this paper is to find an optimal size of different components of an off-grid PV system in the HOMER software with different types of batteries (lead-acid batteries and lithium-ion batteries). The proposed model shows the optimal size of the off-grid PV system for a holiday cottage with regard to eligibility criteria for various types of batteries and the net present cost (NPC). The observed off-grid PV system consists of PV modules, a load, a converter and batteries and it is modelled in the HOMER software. The load is modelled with a daily load diagram for the holiday cottage. For lead-acid and lithium-ion batteries the optimal size of different components of an off-grid PV system for five different scenarios (in respect of the price and life-time) is obtained. In addition, the optimal size of the presented model with respect to different values of capacity shortage ranging from 0% to 5% is presented

2014 ◽  
Vol 2 (35) ◽  
pp. 14577-14584 ◽  
Rhet C. de Guzman ◽  
Jinho Yang ◽  
Mark Ming-Cheng Cheng ◽  
Steven O. Salley ◽  
K. Y. Simon Ng

A CVD-synthesized SiNx LIB anode material exhibits stable, high capacity performance via two stage electrochemical reactions (conversion and then alloying).

2015 ◽  
Vol 162 (10) ◽  
pp. A1935-A1939 ◽  
Christopher J. Pelliccione ◽  
Yujia Ding ◽  
Elena V. Timofeeva ◽  
Carlo U. Segre

2015 ◽  
Vol 2015 ◽  
pp. 1-12 ◽  
Yanju Chen ◽  
Ye Wang

This paper studies a two-period portfolio selection problem. The problem is formulated as a two-stage fuzzy portfolio selection model with transaction costs, in which the future returns of risky security are characterized by possibility distributions. The objective of the proposed model is to achieve the maximum utility in terms of the expected value and variance of the final wealth. Given the first-stage decision vector and a realization of fuzzy return, the optimal value expression of the second-stage programming problem is derived. As a result, the proposed two-stage model is equivalent to a single-stage model, and the analytical optimal solution of the two-stage model is obtained, which helps us to discuss the properties of the optimal solution. Finally, some numerical experiments are performed to demonstrate the new modeling idea and the effectiveness. The computational results provided by the proposed model show that the more risk-averse investor will invest more wealth in the risk-free security. They also show that the optimal invested amount in risky security increases as the risk-free return decreases and the optimal utility increases as the risk-free return increases, whereas the optimal utility increases as the transaction costs decrease. In most instances the utilities provided by the proposed two-stage model are larger than those provided by the single-stage model.

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