BQ78350: SOC corrections at negative temperatures

Hello ,

We are using the BQ78350 and the BQ76930000
For the fuel gauging  there are several parameter at  CEDV_cfg values to enter (like EMF,C0,R0, T0, R1 TC and C1 ).   We have put the 8S1P battery pack in a climate chamber. This to capture measure data values that are needed for the 'Gauge parameter calculator Packager' from BQstudio. We performed test at  -10 degree, 20 degree and 35degree

This done according to Simple Guide to CEDV Data Collection for Gauging Parameter Calculator (GPC). And finally send to  the gpcUpload.tsp. The date that was generated gave the SOC error rate with in the specified limits.

file                                       SOC error, %                    pass
roomtemp_lowrate.csv        0.558723563774061        1
roomtemp_highrate.csv      1.09633817169533           1
hightemp_lowrate.csv        -2.58474160835011           1
hightemp_highrate.csv       -2.73640886693718          1
lowtemp_lowrate.csv          0.0292680324642749       1
lowtemp_highrate.csv        2.69111514030818            1

 After that we entered the new given parameters EMF,C0,R0, T0, R1 TC and C1.
The parameters have control on the Zero point adjustment for the SOC and the SOH above 12 degree (Learning Low temperature).
If we check the SOC at temperatures below freezing point (-10 degree Celsius) and check the SOC we see that there is no correction on the loss of battery capacity. So we do a lot measurements. It looks if the gauging is not taken the Full charge capacity loss at low temperatures.

With the result that the SOC at low temperature is not presenting the real SOC because what we see at the end of discharge is that the SOC is still 18% and the battery is switch off due to COV.

So my question is we performed a lot a testing and file generations to get the CEDV parameters from TI but at the end the SOC results are poor.

Can you explain this ?
is it correct that the BQ78350 is not taken the Full charge capacity loss at low temperatures?
Or do we have missed some things regarding the settings in the BQ78350 that can solve the above issue, are there parameters or bits to set to have correct operations at negative temperatures ?

Kind regards
Rens