BQ27220EVM-744: BQ27220 Gauging Parameter Calculator

Farhad Pirvali

Prodigy 120 points

Part Number: BQ27220EVM-744
Other Parts Discussed in Thread: GPCCEDV

Hi Team,

I measured a Lithium Polymer battery with BQ27220EVM and acquired 3 pair data from the battery:

hightemp_highrate
hightemp_lowrate
roomtemp_highrate
roomtemp_lowrate
lowtemp_highrate
lowtemp_lowrate

+ config.text file

but every time when I submit the data to Gauging Parameter Calculator I got this error:

The following errors were reported by the calculation engine:
Accuracy Error: Deviation is so high that it is most likely due to anomaly in the data. Please check that data files have recomended format, units and test schedule

could you please perhaps check my data and let me know what would be the issue in this file?8357.GPCCEDV.zip

over 3 years ago

0 Shirish over 3 years ago

TI__Guru 57697 points

The low temperature data is bad. For example, the voltage cannot jump like this with proper connections to the battery. There are several low readings. Check that you have good connections while collecting data

0 Farhad Pirvali over 3 years ago in reply to Shirish

Prodigy 120 points

Dear Shirish,

I did the whole measurements again with a solid and good connections. Now the Gauging Parameters for Hightemp and roomtemp is below 2% and they passed. but for the low temp one of them is around 8% and the other one is 18%. but as I checked the values they are seem to be ok. could you please check the data and let me know what would be the problem?

5773.GPCCEDV.zip

+1 Shirish over 3 years ago in reply to Farhad Pirvali

TI__Guru 57697 points

Hello Farhad,

I am not able to find any issue, but the curves don't seem to match the temperature very well. Do you have the temperature sensor closely connected to the cell so that it is able to measure the self heating? That may be a possible issue.

0 Farhad Pirvali over 3 years ago in reply to Shirish

Prodigy 120 points

Hi,

I measured the temperature of the surface of the battery and nothing strange

0 Shirish over 3 years ago in reply to Farhad Pirvali

TI__Guru 57697 points

Hello Farhad,

The deviation in the report is because the data does not match the curves seen with normal batteries. At high rate there is normally self heating, so check if you can place the thermistor in a better location to capture the cell temperature better.

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BQ27220EVM-744: BQ27220 Gauging Parameter Calculator