Bias-Compensated State of Charge and State of Health Joint Estimation for Lithium Iron Phosphate Batteries

Fuente: arXiv
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Main Authors: Yi, Baozhao, Du, Xinhao, Zhang, Jiawei, Wu, Xiaogang, Hu, Qiuhao, Jiang, Weiran, Hu, Xiaosong, Song, Ziyou
Format: Preprint
Published: 2024
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author Yi, Baozhao
Du, Xinhao
Zhang, Jiawei
Wu, Xiaogang
Hu, Qiuhao
Jiang, Weiran
Hu, Xiaosong
Song, Ziyou
author_facet Yi, Baozhao
Du, Xinhao
Zhang, Jiawei
Wu, Xiaogang
Hu, Qiuhao
Jiang, Weiran
Hu, Xiaosong
Song, Ziyou
contents Accurate estimation of the state of charge (SOC) and state of health (SOH) is crucial for the safe and reliable operation of batteries. Voltage measurement bias highly affects state estimation accuracy, especially in Lithium Iron Phosphate (LFP) batteries, which are susceptible due to their flat open-circuit voltage (OCV) curves. This work introduces a bias-compensated algorithm to reliably estimate the SOC and SOH of LFP batteries under the influence of voltage measurement bias. Specifically, SOC and SOH are estimated using the Dual Extended Kalman Filter (DEKF) in the high-slope SOC range, where voltage measurement bias effects are weak. Besides, the voltage measurement biases estimated in the low-slope SOC regions are compensated in the following joint estimation of SOC and SOH to enhance the state estimation accuracy further. Experimental results indicate that the proposed algorithm significantly outperforms the traditional method, which does not consider biases under different temperatures and aging conditions. Additionally, the bias-compensated algorithm can achieve low estimation errors of below 1.5% for SOC and 2% for SOH, even with a 30mV voltage measurement bias. Finally, even if the voltage measurement biases change in operation, the proposed algorithm can remain robust and keep the estimated errors of states around 2%.
format Preprint
id arxiv_https___arxiv_org_abs_2401_08136
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Bias-Compensated State of Charge and State of Health Joint Estimation for Lithium Iron Phosphate Batteries
Yi, Baozhao
Du, Xinhao
Zhang, Jiawei
Wu, Xiaogang
Hu, Qiuhao
Jiang, Weiran
Hu, Xiaosong
Song, Ziyou
Systems and Control
Accurate estimation of the state of charge (SOC) and state of health (SOH) is crucial for the safe and reliable operation of batteries. Voltage measurement bias highly affects state estimation accuracy, especially in Lithium Iron Phosphate (LFP) batteries, which are susceptible due to their flat open-circuit voltage (OCV) curves. This work introduces a bias-compensated algorithm to reliably estimate the SOC and SOH of LFP batteries under the influence of voltage measurement bias. Specifically, SOC and SOH are estimated using the Dual Extended Kalman Filter (DEKF) in the high-slope SOC range, where voltage measurement bias effects are weak. Besides, the voltage measurement biases estimated in the low-slope SOC regions are compensated in the following joint estimation of SOC and SOH to enhance the state estimation accuracy further. Experimental results indicate that the proposed algorithm significantly outperforms the traditional method, which does not consider biases under different temperatures and aging conditions. Additionally, the bias-compensated algorithm can achieve low estimation errors of below 1.5% for SOC and 2% for SOH, even with a 30mV voltage measurement bias. Finally, even if the voltage measurement biases change in operation, the proposed algorithm can remain robust and keep the estimated errors of states around 2%.
title Bias-Compensated State of Charge and State of Health Joint Estimation for Lithium Iron Phosphate Batteries
topic Systems and Control
url https://arxiv.org/abs/2401.08136