Work

Study on OCP Optimization and EIS-Based SOH Estimation for LiFePO4 Battery Packs Under Motor Load Conditions

Year: 2026

Type: article

Abstract: This study proposes an optimization strategy for the over-current protection (OCP) parameters of a lithium iron phosphate (LiFePO₄, LFP) battery system used in electric golf carts operating under high motor-load conditions. Real-world hillclimbing tests were conducted under four clearly defined payload/passenger conditions to analyze the transient discharge-current pro-file, voltage sag, and cell-temperature response. The maximum discharge current reached -238.2 A under the 200 kg cargopayload and one-passenger condition, and the current interval exceeding 150 A lasted up to 27 s. The maximum instantaneous power was 11.05 kW. Thermal analysis showed that the cell-temperature rise was within 2°C and the maximum measured cell temperature was 22.3°C. Linear regression of voltage and current yielded R² = 0.9368 and dV/dI = 0.0126 Ω, which was used as the DC internalresistance estimate. Based on these quantitative results and the cell specification limit of 300 A continuous discharge, the OCP threshold was reviewed from 250 A to 280 A to improve driving continuity while remaining below the allowable continuous-discharge current. EIS-based SOH estimation and the AI-BMS variable protection logic are presented as an extension framework for reflecting temperature and aging effects in future OCP-setting decisions.

Source: Journal of the Korean Institute of Electrical and Electronic Material Engineers

DOI: 10.4313/jeem.2026.39.4.11

Authors: Woo-Geun Jung, Jae-Ha Ko, Keon-Sik Hong

Institution: Honam University

Language: English

Topic: Battery Modeling and Management

Subfield: Automotive Engineering

Field: Engineering

Domain: Physical Sciences

SDG: Affordable and clean energy

Open Access status: diamond

Funder: Honam University