LiFePO4 Cell Characterization

Hello,

We are designing a battery pack that uses LTC4015 as a charger. The datasheet says, IC can coloumb count. I want to use that feature. But I have some considerations about reliable SoC estimation. The nature of lithium based cells can be effected very easily from temperature. This disadvantage occurs dynamic changing in capacity of the cells. In my opinion, to solve this problem IC needs to learn characterization of the cell. In our design, temperature is changing in very dynamically. I didn't find detailed information about this situation. I hope, I explained well my consideration about coulomb counting.

You can find my questions in below.

  • Is LTC4015 counting only coulombs?

If no,

  • Could LTC4015 can learn this cell characterization?

If yes,

  • Is there a any procedure of learning phase?

Thank you.

Bahadir

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  • +1
    •  Analog Employees 
    on Feb 4, 2021 7:03 PM 2 months ago

    Hi Bahadir,

    Yes, LTC4015 only counts coulombs and is not in itself an SoC monitor. It is really just a piece of an SoC monitor. It effectively gives you all of the information you need to do this (instantaneous voltage/current, BSR, temperature, coulomb count) but leaves you to do the characterization and SoC estimation manually in your microcontroller code.

    So, no, it does not learn cell characterization. The intention is for the microcontroller code to handle this aspect of the SoC estimation.

    Regards,

    Zack

Reply
  • +1
    •  Analog Employees 
    on Feb 4, 2021 7:03 PM 2 months ago

    Hi Bahadir,

    Yes, LTC4015 only counts coulombs and is not in itself an SoC monitor. It is really just a piece of an SoC monitor. It effectively gives you all of the information you need to do this (instantaneous voltage/current, BSR, temperature, coulomb count) but leaves you to do the characterization and SoC estimation manually in your microcontroller code.

    So, no, it does not learn cell characterization. The intention is for the microcontroller code to handle this aspect of the SoC estimation.

    Regards,

    Zack

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