International audienceDerived from the Pseudo Two-Dimensional mathematical structure, a simplified electrochemical and thermal model of LiFePO4-graphite based Li-ion batteries is developed in this paper. Embedding the porous electrode theory, this model integrates the main design parameters of Li-ion systems and its partial differential equations mathematical structure makes it a promising candidate for battery management system (BMS) applications and comprehensive aging investigations. Based on a modified Single-Particle approach, the model is used to simulate and discuss capacity restitution in galvanostatic charges and discharges at various rates and temperatures. Constant high-rate solicitations similar to fast charge of plug-in electric vehicles or electric vehicles, are experimentally tested and simulated with the present model. Also, thermal issues occurring during these specific operating conditions are quantitatively pointed out. The concept of current-dependent spherical particle radius is used to obtain good agreement with experimental data related to galvanostatic charges and discharges. The capabilities and limits of this preliminary modeling work are discussed in detail and ways to extend the potentialities of this approach to BMS applications are proposed

International audienceIn this paper, an isothermal physics-based agingmodel from the literature is modified and extended to simulate both capacity and power fade of a commercial LiFePO4-graphite Li-ion battery. Compared to the isothermal reference, themechanism of porosity modification due to the Solid Electrolyte Interphase (SEI) film growth at the negative electrode is integrated in the present electrochemical and thermalmodel to establish theoretical correlations between capacity and power fade of the system. The agingmodel includes different contributions of the cell impedance increase such as the SEI film resistance and the electrolyte mass transport resistance due to the mitigation of the negative electrode porosity. Experimental databases from literature and specific experiments coupling endurance tests and Electrochemical Impedance Spectroscopy results, are used to calibrate and validate the correlated power and capacity loss simulations for both calendar and classic galvanostatic cycling operating conditions. The analysis of the experimental data points out that an additional possible aging mechanism such as cracking and fracture of the SEI layer could play an important role for cycling operating conditions and accelerate the electrochemical mechanisms. The impact of physical and design parameters on the power and capacity theoretical correlations are discussed. The limits of applicability of the present model are also discussed in this paper

ln this paper an empirical capacity fade model for Li-ion batteries has been developed, calibrated and validated for a NCA/C and a LFP/C Li-ion cell. Based on extensive experimental work, it is able to describe both cycle and calendar effects on aging. The stress factors taken into account for each aging mode are the state of charge and the tempe rature for calendar aging, and the temperature and the current for cycle aging. A simple approach has been adopted in order to instantaneously apply either cycle aging or calendar aging according to operating conditions and th us accurately mode! aging effects due to dynamic operating conditions. This model has then been coupled to an electrothermal mode l and integrated in a system simulation software application in order to assess the effect of charging strategies and V2G on battery lifetime. When compared, LFP/C and NCA/C exhibited different behaviors when submitted to V2G scenarios. Light V2G scenarios led to a low aging for LFP/C based battery but tended to slightly increase the aging of NCA/C based battery according to simulations.

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This paper presents a methodology dedicated to component sizing and fuel consumption evaluation of different degree of hybridization for light duty vehicles applications. The methodology will be described together with vehicle and components simulation and sizing principles. To ensure a systematic approach, with no bias for any of the cases considered, the energy management of the hybrid drivetrain will be carried out thanks to an optimization based on the Pontryagin's Minimum Principle. As hybrid fuel consumption is highly dependant on vehicle type of use, the hybrid vehicles will be evaluated on different actual use driving patterns as well as on missions representing the daily usage of the vehicle. The methodology and a panel of results are presented in the paper.