SOC-Dependent Soft Current Limiting for Second-Life Lithium-Ion Batteries in Off-Grid Photovoltaic Battery Energy Storage Systems

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dc.contributor.authorWang, Hongyan
dc.contributor.authorChiradeja, Pathomthat
dc.contributor.authorNgaopitakkul, Atthapol
dc.contributor.authorYoomak, Suntiti
dc.date.accessioned2026-08-06T10:55:05Z
dc.date.available2026-08-06T10:55:05Z
dc.date.issued2026-04-01
dc.description.abstractThe increasing deployment of off-grid photovoltaic–battery energy storage systems (PV–BESSs) has intensified operational demands on battery energy storage, particularly when second-life lithium-ion batteries are employed. Due to aging-induced increases in internal resistance and reduced thermal margins, second-life batteries are more vulnerable to high-current operation at a low state-of-charge (SOC), which aggravates heat generation and accelerates degradation. In this study, an SOC-dependent soft current limiting strategy is proposed that reshapes the discharge current reference under low-SOC conditions while maintaining fixed SOC limits, thereby targeting current-domain protection rather than SOC-boundary adaptation for reliable off-grid operation. The proposed method introduces two SOC thresholds to gradually derate the allowable discharge current, preventing abrupt current changes near the lower SOC bound. A unified MATLAB/Simulink-based framework is developed for a 24 h representative off-grid PV–BESS scenario using a second-order equivalent circuit model coupled with a lumped thermal model. Simulation results show that the proposed current shaping reduces low-SOC current stress and associated Joule heating, leading to moderated temperature rise, while only slightly affecting the unmet load under the tested conditions. These findings indicate that SOC-dependent current shaping can provide a control-oriented means to reduce low-SOC electro-thermal stress in second-life batteries within the studied off-grid PV–BESS framework.
dc.identifier.citationComputation, 14(4), 2026
dc.identifier.doi10.3390/computation14040095
dc.identifier.issn20793197
dc.identifier.other2-s2.0-105037019699
dc.identifier.urihttps://dspace.kmitl.ac.th/handle/123456789/17989
dc.sourceComputation
dc.subjectbattery energy storage systems
dc.subjectelectro-thermal stress mitigation
dc.subjectoff-grid photovoltaic systems
dc.subjectsecond-life lithium-ion batteries
dc.subjectsoft current limiting
dc.subjectstate-of-charge-dependent control
dc.titleSOC-Dependent Soft Current Limiting for Second-Life Lithium-Ion Batteries in Off-Grid Photovoltaic Battery Energy Storage Systems
dc.typeArticle

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