Out-of-equilibrium thermodynamics analysis of lithium-ion batteries upon non-linear voltammetry fast charging

• Published in: Journal of power sources 2024-12, Vol.624, p.235595, Article 235595
• Main Authors: Li, Shiqi, Peng, Jimmy Chih-Hsien, Yazami, Rachid
• Format: Article
• Language: English
• Subjects: Fast charging; Lithium-ion battery; Non-linear voltammetry; Out-of-equilibrium thermodynamics; Pseudo-open-circuit voltage
• ISSN: 0378-7753
• DOI: 10.1016/j.jpowsour.2024.235595

We present an out-of-equilibrium thermodynamics method for lithium-ion batteries’ (LIB) state-of-charge (SOC) assessment during ultra-fast charging using the non-linear voltammetry (NLV) algorithm. NLV consists of applying short constant voltage pulses followed by a very short relaxation period. The out-of-equilibrium open-circuit voltage during the relaxation period is addressed to as pseudo-open-circuit voltage (p-OCV). From the p-OCV temperature dependence, pseudo-entropy and pseudo-enthalpy are determined, denoted as p-ΔS and p-ΔH, respectively. It is found that the SOC follows the “Yazami theorem”, which theorizes that SOC is a linear function of p-ΔS and p-ΔH. Out-of-equilibrium p-ΔS and p-ΔH together with incremental capacity (IC) analysis reveal different steps during the charging process, which are assigned to phase transitions in the LIB’s anode and cathode materials. •Estimation of out-of-equilibrium thermodynamics during the fast charging process.•Analysis of non-linear voltammetry fast charging under various operating conditions.•High accuracy SOC assessment from out-of-equilibrium thermodynamics.•Battery temperature prediction during NLV ultra-fast charging.