Pulse resistance based online temperature estimation for lithium-ion cells

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