Its a current shunt, it needs to be small to avoid interfering with the cell voltage measurement.
Yes, a non-inverting amp will do the job, you need a rail-to-rail low voltage opamp that has both
input and output ability to go all the way down to the -ve rail (ie ground in a single supply
setup). Low input offset voltage will be important I suspect, so a precision rail-to-rail low-voltage
opamp.