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CCS/BQ27510-G3: BQ27510-G3

Part Number: BQ27510-G3

Tool/software: Code Composer Studio

I am sorry for opening another loop to talk this problem further. Because it is urgent, I hope to get fast answer. Thanks for your answer above! I have further questions.

 1, Is truesoc accurate in storage mode if it can't see 0.2mA leakage? Can trucesoc take capacity loss of chemical characteristic and leakage current into consideration during long term storage? How can you make sure truesoc is equal to real capacity during long term storage? How many accuracy does it have between truesoc and real capacity?
2,If I disable smoothing soc function, does I need to do learning cycle again?

3,When I set operation configuration D[SMTHEN] to 0, it disables smoothing function and soc will be same with unfiltered soc. Is this understanding right?

4,According to your explanation, soc reading of one 100% cell will still be 100% after one year storage, but real capacity of cell will be 40%. When it is charged again after this one year storage, soc reading will increase form 100%. Is this understanding right?

5,If I disable smoothing function to align soc with truesoc, what disadvantage does FG have? What happen to FG truesoc reading?

6,Our FG will be SEALED mode in production line. Could you write process about how to rest FG step by step?
7,How does rem cap simulation work?
8,What influence does coulomb counter have for soc and truesoc during storage mode?

Background:

Answer form Onyx:

With Smoothing enabled, if the current is less than 1mA, with a ccdeadband of 17mA, that will be discarded. The filtered SOC which is what will be reported will stay constant. The true SOC will reflect the actual value because of Rem cap simulations at grid points. If there is a tempeature change of more than 5 degrees in storage, a rem cap simulation would occur that will adjust the filtered SOC to the true SOC.

in question 2, when charging starts a rem cap simuation is run. The filtered SOC will increase to 100%. It will not jump to 80%.

pls note that the gauge reports both true SOC and filtered SOC. After being in storage, you can force filtered SOC to be equal to true by issuing a reset command or charge the cells to full (taper conditions)) or discharge to terminate voltage for the true SOC and filtered SOC to be come equal.

Question form my side:

1,In our application, deadband of new firmware is 68. Leakage current on our board is 0.2mA when board is put in shelf. According to chemical characteristic, 100% cell will decrease 20% capacity after one year. 

What is soc reading after one year storage for one 100% cell? How about 2 years? Could you evaluate soc reading in one and two years period? Is it higher than real capacity and how much? Is it possible that soc reading is 75% but real capacity is 0% during storage? Could it make sure that cell with 75% or higher soc reading has at least 15% real capacity during two years storage period? How much is deviation between soc reading and real capacity during 2 years storage?

2,For example, soc reading of one 100% cell at the beginning of storage becomes 98%, but real capacity of cell is 80% after one year storage. Does soc reading increase from 98% to 100% when this cell is charged again after one year storage ? Or does soc reading fall to 80% and then increase to 100% ? When does this cell complete learning current characteristic? When can soc reading be accurate?


Thanks a lot! And appreciate your answer!

  • 1. True SOC (unfiltered SOC) will get adjusted based on OCV while in storage. This adjustment will account for for the 0.2mA current, such that even though the couloumb counter discards that, the OCV/DOD measurements will adjust SOC to reflect battery discharge due to self discaharge of the cell. Unfitered SOC will be correct while in storage, but filtered will not since the gauge will not be seeing any current flow

    2. if you disable smoothing, you do not have to redo learning again. i would not recommend you disable smoothing as that allows for a better user experience incase temperature or the load magnitude changes. if you want the unfiltered SOC and fitered to be the same after storage, you can issue a reset command after the battery is taken out of storage.

    3. yes, SOC reported will be the same as unfiltered SOC.

    4. The filtered SOC will remain at 100% , while the true will increment from 40% to 100% until taper conditions are met. Filtered SOC is not allowed to increase or decrease if there is no current flow. If the temperature increases or decreases by more than 5 degrees, then a rem cap simulation would occur and make the filtered and unfiltered SOC the same. ie the filtered will get corrected to 40%
    5. Do not disable smoothing. This is not recommended. See answer 2 above.
    6. if the device is sealed, you need to send the unseal command and then issue the reset command. Once you issue the reset command, the device will go back to being sealed.
    7. see app note: www.ti.com/.../slua450
    8. if current measured by the coulomb counter is below the current filtered by the cc deadband, then it would not play into the true SOC or filtered SOC.

    thanks
    Onyx
  • Thanks so much for your excellent answer!