Battery Management System (BMS)

Fault Detection and Short Resistance Estimation in Parallel Connected Lithium-ion Batteries ISC detection in parallel connected cells challenging because in large packs, unmeasured internal currents can obscure charge loss and voltage drop measurements from the faulty cell. Researchers at the University of Michigan used the Interacting Multiple Model IMM technique combined with unscented Kalman filters UKFs to estimate the probability for the occurrence of an ISC and the short-circuit resistance. It relies on dynamic electrothermal models both for the healthy and short-circuit modes to calculate the mode probability. Detection time, temperature rise, and steady state error

IMMʼs performance with ISC resistance evolving from 100 Ω to 0.1 Ω in 3hrs

HARD SHORT

SOFT SHORT

IMM can successfully detect and estimate a wide range of ISC resistances before large temperature rise in a pack (less than 6°C before detection) validated on 50 synthetic scenarios in which one cell in a 46P pack underwent an ISC during a drive cycle. Source: H. Movahedi et al., Journal of Dynamic Systems, Measurement, and Control 2025

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