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Communication Dans Un Congrès Année : 2023

Analysis of Limiting Processes of Power Performance Within Li-ion Batteries

Mohamed Raghibi
Didier Devaux
R. Bouchet

Résumé

Li-ion batteries have become a necessity in human daily life as the most versatile, efficient and performing energy storage & conversion system to power our nomad electronic, cars and buffer the renewable intermittent energy sources.1 However, improvement of current battery systems is needed to meet the requirements of the transport sector in terms of energy density, safety, and cycle life. Besides the active materials, among the strategies to increase battery autonomy, one consists of optimizing the design parameters of the electrode such as the formulation, loading, microstructure, and porosity. The idea is simply to increase the ratio of active materials (negative and positive electrode thickness) to inactive components (separator, current collector…). However, by doing so, the output power density becomes strongly limited by the charge transport within the composite electrodes. Thus, our objective is ultimately to optimize the battery design to find the best compromise between energy and power density in Li-based batteries.2 In this work, we study Li-battery capacity as a function of the current density with respect to electrode porosity, formulation, loading, microstructure as well as temperature. For this purpose, (LiFePO4) LFP and (LiNi0.8Mn0.1Co0.1O2) NMC-811-based electrodes were formulated at different loadings (from 0.4 to 3.4 mAh.cm-2), compositions (Active material%, Carbon%, PVDF %), and calendered to reach different porosities (from 20 to 50 %). The microstructure of electrodes is investigated using SEM, Granulometry and BET to determine their microstructure and specific area. The electrode tortuosity is analysed through impedance spectroscopy in a symmetric positive/positive electrode.3 Subsequently, the power performance is fully captured and analyzed using a time-saving methodology.4 The limiting current density, Jlim, is obtained through capacity vs discharge current curves, which allows us to determine an effective diffusion coefficient of the limiting transport process (Deff) via Sand equation. We also analyse the diffusion coefficient and charge transfer resistance (Rct) as a function of the state of charge (SOC) by coupling GITT and EIS. Afterwards, the correlation between design parameters and the effective electrochemical parameters such as Deff and Jlim, Rct is discussed

Domaines

Chimie
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Dates et versions

hal-04230730 , version 1 (06-10-2023)

Identifiants

  • HAL Id : hal-04230730 , version 1

Citer

Mohamed Raghibi, Laureline Lecarme, Didier Devaux, R. Bouchet. Analysis of Limiting Processes of Power Performance Within Li-ion Batteries. 74th Annual Meeting of the International Society of Electrochemistry, International Society of Electrochemistry (ISE), Sep 2023, Lyon, France. ⟨hal-04230730⟩
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