Pulse resistance based online temperature estimation for lithium-ion cells

S. Ludwig, I. Zilberman, M. F. Horsche, T. Wohlers, A. Jossen

Research output: Contribution to journalArticlepeer-review

18 Scopus citations

Abstract

Knowing the temperature distribution within a battery pack is vital, because of the impact on capacity loss, power degradation and safety. Temperature measurements are usually realized with temperature sensors attached to a limited number of cells throughout the battery pack, leaving the majority of cells in larger battery systems unattended. This work presents a novel sensorless method for determining the temperature of a cell by exploiting the relation of the cell's overpotential and temperature exemplary using a 18650 nickel-rich/silicon–graphite cell, although the method is basically applicable to any cell. Current changes in the battery load are utilized as pulse excitation for the calculation of a direct-current resistance RDC,Δt determined after a certain time Δt. Reference pulses at 10/20/30/40°C are recorded to investigate the influence of state-of-charge and pulse rise/fall-time, as well as the pulse-current amplitude and direction on RDC,Δt. The analysis of the reference pulses shows that a Δt in the 10ms to 100ms regime has the greatest sensitivity to temperature and the least dependence on other parameters. The method is finally validated using a 6s1p-module with an externally constant temperature gradient applied to the serial connection, showing an average estimation error smaller than 1K for each cell.

Original languageEnglish
Article number229523
JournalJournal of Power Sources
Volume490
DOIs
StatePublished - 1 Apr 2021

Keywords

  • Battery management system
  • Cell resistance
  • Lithium-ion battery
  • State estimation
  • Temperature estimation

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