Hi, my customer has such issues in their factory, please help answer customer's questions first and suggest on what we can do to help, Thanks!
1, it is one BBU(battery backup unit) project which uses BQ40Z60 as BMS, and it is 2S1P battery pack which is designed totally by customers
2, recently there is one PF(permanent failure) reported from customer's manufacturing team(based in U.S.), with a very high failure rate(more than 80% based on limited sample quantity, 6 of 8). After further decoding, it is reported with CFET failure(charge FET failure), below is all what customer can find from TI technical document
3, Cusotmers do not make change to this threshold of BQ setting, which means it is still 5mA/5s in this BBU
4, They are pretty sure that there is NO real charge FET failure, it is more likely to be unexpected triggering, the failure only occurs under cold temperature(5-8C)
Currently customers believe the questions to TI BU team are:
1, under which conditions will CHGR be off?
2, do you foresee any side effect if increasing the threshold?
3, there is CC auto offset calibration function for this BQ, is that helpful to this kind of fault? Do we need to perform that calibration manually?
