BQ27Z561-R1: SoC jump due to temp change

Ryan Wang

Expert 5480 points

Part Number: BQ27Z561-R1
Other Parts Discussed in Thread: GPCRB

Dear expert,

My BQ27Z561R1 works fine for both 25C and -10C temperature.

However, when temperature suddenly jump from -1C to -10.3C as below table in yellow, SoC jump from 18% to 16%.

How to avoid this? I already enabled smooth engineer.

Temp	Vbat	Ibat	AIbat	Rm	Soc
284	3634	-1019	-877	918	19
287	3610	-1124	-936	916	19
290	3593	-1275	-1010	915	19
292	3613	-1072	-1047	913	19
297	3625	-814	-1023	912	19
298	3650	-820	-962	911	19
295	3723	-259	-823	910	19
85	3769	-33	-13	901	19
-10	3772	-9	-13	882	18
-103	3761	-12	-10	764	16

Below is DFFS file I used.

configure.df.fs

over 1 year ago

0 Shirish over 1 year ago

TI__Guru 57747 points

Hello Ryan,

Have you optimized low temperature performance using GPCRB tool?

0 Ryan Wang over 1 year ago in reply to Shirish

TI__Expert 5480 points

Shirish,

Yes, RBteak is done at -10C.

-10C discharge test is very good.

I attach gg file here in case you needed.

2604.config.gg.csv

0 Shirish over 1 year ago in reply to Ryan Wang

TI__Guru 57747 points

Hello Ryan,

Remcap will drop at very low temperature. At low RSOC, there may not be enough room to smooth. Also how fast is the temperature dropping? From 85 to -10 seems unrealistic in a very short time

0 Ryan Wang over 1 year ago in reply to Shirish

TI__Expert 5480 points

Shirish,

It is 5s for every line log.

It takes 10s from 8.5C to -10C.

So you think 18% (-1C) jump to 16%(-10.3C) in 5s is normal?

+1 Shirish over 1 year ago in reply to Ryan Wang

TI__Guru 57747 points

SOC will drop with temperature. That is normal.

The change in temperature in just 5 seconds can create other issues because it is hard physically for the battery to be cooled internally in such a short time. This will cause a mismatch between actual and reported capacity

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BQ27Z561-R1: SoC jump due to temp change