The ATA6871 is a battery cell monitoring circuit designed to act as an emergency, safety, or backup circuit in Li-ion battery systems for electrical and hybrid electrical vehicles (EV/HEV). It monitors overvoltage, undervoltage, and the cell temperature in Li-ion batteries without the need of a microcontroller. The circuit has an advanced self-test functionality, which checks the proper functionality of the monitoring comparators as well as the communication lines. It can be used as a monitoring circuit as well as an emergency indicator or as a backup system in Li-ion battery management systems. The ATA6871 can monitor four, five, or six battery cells. Up to 16 IC's can be cascaded. If one or more battery cells exceed the over or undervoltage thresholds for longer than 2 seconds, or if the temperature input exceeds the temperature limit for more than 2 seconds, a digital output signal is set to high.