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BQ24610: Battery pack design

Piero Mistretta
Prodigy 80 points
Part Number: BQ24610

Hello,

I'm starting a project for a battery charger made up of 5 modules. Each module contains, approximately (the entire battery pack composition is not yet defined), 140 lithium batteries in configuration 20S7P.

  1. Could I use the BQ24610 as battery charger?
  2. It charges only a series of 5-6 batteries and I have to charge many series of 20-25 batteries. Could I divide the entire battery pack in elementary cells made up of 5?
  3. If question 2 have an affirmative answer, how could I connect every device for a safe behaviour? 
  4. I suppose I need a battery balancer. Which device do you suggest?
  5. Do you suggest other charger devices or configuration?

Any information, in this project phase, can be very useful so I encourage you to suggest your way to proceed.

Thank you for the support

Best regards

Piero Mistretta 

  • 0
    TI__Mastermind 24075 points

    Hi Piero,

        BQ24610 can only charge maximum of 6 series lithium batteries. LiIon batteries in parallel self balance.  Even if one ages differently than the other, and therefore becomes more resistive, the cells will still self balance through their resistances.  Balancing batteries in parallel is complex, requiring independent gauges, isolation, discharge and charge switching circuitry for each battery. With regards to output voltage, SRN has a max of 33V, but the 26V max output voltage is because of normal operating voltage of VIN. This should not exceed 28V, and because this is a buck charger, input voltage should be about 2V higher than output voltage to prevent from entering SLEEP.

       Can you elaborate more on what you mean by dividing into elementary cells of 5? You can take a look at our balancer portfolio here:http://www.ti.com/power-management/battery-management/monitors-balancers/overview.html

       Currently this part can charge at the highest output voltage that our portfolio has to offer.

  • 0 in reply to Kedar Manishankar
    Prodigy 80 points

    Hello,

    about your question " Can you elaborate more on what you mean by dividing into elementary cells of 5?".

    I need to charge a battery pack composed by many Li-Ion batteries connected, charged used BQ24610 and balanced  as showed below:

  • 0 in reply to Piero Mistretta
    TI__Mastermind 24075 points

    Hi Piero,

       This solution will not work as BQ24610 will have individual ground return paths to charge the battery cells of 5, and not one solid ground return path back to the input. Splitting up the pack into elementary cells would not work. Our current portfolio does not support such high voltage charging.