  Safety, reliability, and durability are targets of all engineering systems,
including Li-ion batteries in electric vehicles. This paper focuses on sensor
setup exploration for a battery-integrated modular multilevel converter
(BI-MMC) that can be part of a solution to sustainable electrification of
vehicles. BI-MMC contains switches to convert DC to AC to drive an electric
machine. The various configurations of switches result in different operation
modes, which in turn, pose great challenges for diagnostics. The study explores
diverse sensor arrangements and system configurations for detecting and
isolating faults in modular battery packs. Configurations involving a minimum
of two modules integrated into the pack are essential to successfully isolate
all faults. The findings indicate that the default sensor setup is insufficient
for achieving complete fault isolability. Additionally, the investigation also
demonstrates that current sensors in the submodules do not contribute
significantly to fault isolability. Further, the results on switch positions
show that the system configuration has a significant impact on fault
isolability. A combination of appropriate sensor data and system configuration
is important in achieving optimal diagnosability, which is a paramount
objective in ensuring system safety.
