BQ27542-G1: discharge issue at -20 degree

Tommy Tzeng

Part Number: BQ27542-G1

Hi Team,

we use GPC to get the report,but the pack directly discharge RSOC at -20 degrees,and the RSOC is about 8x% and directly to 0%,

and the customer system can not turn on at -20 degree,so what happen to cause this problem? there problem with the battery specificaion?

please kindly refer the attached.

ICP535172AWRU pre spec_STD(4.4V)160928.pdf

AKH08-20200422.gg.csv

AKH08-(-20C)放置LOG.xlsx

AKH08_GPC_Rb.zip

AKH08_GPC_Chem ID.zip

AKH08_GPC_Chem ID-report.zip

AKH08_GPC_Rb-report.zip

over 5 years ago

0 Damian Lewis over 5 years ago

TI__Mastermind 34775 points

Hello Tommy,

The drop to 0% is because Terminate Voltage 3200mV was reached. We need to understand why the SOC was being overestimated. Can you log the data with FCC, Rem Cap and True/unfiltered SOC being reported.

0 Tommy Tzeng over 5 years ago in reply to Damian Lewis

Genius 5790 points

Hi Damian Lewis,

sir,

attached is customer log data,please kindly reference.

first run-04AKH08-(-20C)放置LOG.xlsx

second run-AKH08-(-20C)LOG.xlsx

0 Andy Liu (BMS) over 5 years ago in reply to Tommy Tzeng

TI__Guru 52115 points

Hi Tommy,

-20C is usually quite challenging for batteries. Mose of them cannot perform well at that low temperature and have a little useable capacity.

I have calculated the battery's useable capacity at -20C. My calculation shows that the capacity is about 301mAh, which is just 10% of its design capacity. See the excel below.

first run-04AKH08-(-20C)_analysis.xlsx

Bascially, the root cause of this SOC jump is the characteristic of the battery cell.

Andy

Power management

Power management forum

BQ27542-G1: discharge issue at -20 degree