Low-complexity online estimation for LiFePO4 battery state of charge in electric vehicles

This paper proposes a low-complexity online state of charge estimation method for LiFePO4 battery in electrical vehicles. The proposed method is able to achieve accurate state of charge with less computational efforts in comparison with the nonlinear Kalman filters, and also can provide state of health information for battery management system. According to the error analysis of equivalent circuit model with two resistance and capacitance, two proportional-integral filters are designed to compensate the errors from inaccurate state of charge and current measurements, respectively. An error dividing process is proposed to tune the contribution of each filter to the finial estimation results, which enhances the validation and accuracy of the proposed method.

https://doi.org/10.1016/j.jpowsour.2018.05.082

Highlights

  • Battery SOC is estimated with a low-complexity online method.
  • Errors in the battery two RC equivalent circuit model are analyzed.
  • Two PI filters are designed to compensate the errors in the battery model.
  • An adaptively adjusted process is proposed to form the fusing weights of the PI filters.
  • The execution time of the algorithms is measured on the MicroZed development board.

Authors: Jinhao Meng(a), Mattia Ricco(b), Anirudh Budnar Acharya(c), Guangzhao Luo(a), Maciej Swierczynski(d), Daniel-Ioan Stroe(b), Remus Teodorescu(b)

a School of Automation, Northwestern Polytechnical University (NPU), Xi’an, 710072, China
b Department of Energy Technology, Aalborg University, Aalborg, 9220, Denmark
c Department of Electric Power Engineering, Norwegian University of Science and Technology, Trondheim, 7491, Norway
d Lithium Balance A/S, Smørum, 2765, Denmark

Jon Fold von Bülow

Jon Fold von Bülow recieved his Cand. Scient. in Nanoscience from University of Copenhagen in 2011 and is currently working with upscaling Li- and Na-ion battery materials to the 100+ kg scale for Haldor Topsøe A/S.

Jon's main interest lies in energy technologies for the future and he started working with fusion energy at Risø National Laboratory for Sustainable Energy. He has since developed a growing interest in technologies that are closer to potential industrial application. He is a highly dedicated academic as well as a very active professional and have initiated and participated in many different projects.

His studies within nanotechnological material science and affiliation with Risø National Laboratories has taken him to Germany, China and the US, where he has collaborated independently with several international research groups. He has so far succeeded in pushing two academic projects to industrial application, first with the Danish company Coloplast A/S and recently with a California-based battery start-up – an invention that is currently being US patented.

Jon has conducted most of his work on Li-batteries in the facilities of California NanoSystems Institute (CNSI) as a research scholar at UCSB-MIT-Caltech Institute for Collaborative Biotechnologies (ICB). The manganese based cathode materials he fabricated during this period were all tuned for high-power applications and covers synthesis of various manganese oxides from solution, molten and solid states.

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