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BQ79616-Q1: how to keep the fault register value?

Howard Zou
Genius 12365 points
Part Number: BQ79616-Q1
Other Parts Discussed in Thread: BQ79616

Hi,

my customer want to build their BMS system for energy storage in solar system with our BQ79616.

They would like to use 10 BQ79616 with daisy chain connected, and connect to one BMU board with BQ79600.

Each BQ79616 and 16s cells forms a battery module which is detachable.

They may replace each battery module in the whole energy storage system, and they would like the fault registers value in BQ79616 be kept, so we can check the fault signal of the detached battery module.

How can we achieve that?

They don't want to add one MCU for each BQ79616 because it would cost too much. They said if they need to add MCU, then it's meaningless to use daisy chain connection. They said that daisy chain's main benefit is to help them save cost by removing the MCU connected to each BQ79616.

  • 0
    TI__Genius 17370 points

    Hi Howard,

    Can you explain the process of detaching the battery module and why the old faults would need to be kept? Would the 616 stay powered on by the battery cells and stay connected to the original battery module? If so then it will keep the faults. BUT if you disconnect power to 616 and it goes to shutdown mode you will lose all previous faults. A workaround could be to read back the faults before power down and log them on host side but I'm not sure what the need of this would be to do.

    Regards,

    Taylor

  • 0 in reply to Taylor Vogt
    TI__Genius 12365 points

    Taylor,

    the customer's product is:

    BQ79616 board+battery form a pack(I don't know the exact phrase so I use the word pack).

    BQ79600+MCU form a BMU board.

    The customer could buy whatever number of packs + 1BMU board to form their own system.

    It means that the relationship between pack and BMU is not fixed.

    At manufacturing stage, we have to keep battery information such as battery batch on BQ79616 board.

    When we need to replace one pack in the system, we hope that the fault information is stored on BQ79616 board. We can not assure the battery in this pack still has enough voltage to supply the board.

    The customer wonders if they could add EEPROM on each BQ79616 board, and the BMU board could send signal to BQ79616 to let BQ79616 store its register information on that EEPROM.

  • 0 in reply to Howard Zou
    TI__Genius 17370 points

    Hi Howard,

    Ok I understand - yes the customer can use EEPROM if they are willing to use four GPIOs as SPI master as explained in the datasheet to interface with EEPROM for each device desired. 

    Regards,

    Taylor