3 Replies Latest reply: Feb 19, 2014 6:48 AM by CatherineR RSS

    CN0235: Fully Isolated Lithium Ion Battery Monitoring and Protection System

    CFTL

      Add your comments about the Circuit Note found at http://www.analog.com/en/circuits-from-the-lab/CN0235/vc.html.

        • 1. Re: CN0235: Fully Isolated Lithium Ion Battery Monitoring and Protection System
          erika.walden

          Hello my name is Erika. I am a student at Valparaiso University designing a hybrid powertrain for a car for a senior design project. We are using 34 Lithium Ion Phosphate cells that have 3.2 V apiece to power an electric motor. The batteries will be put in series to make 108 volts. We have been looking at the CN-0235 evaluation board as the battery management protection device. My questions are:

           

          1) How many cells will one evaluation board monitor? Will we have to daisy-chain multiple boards together?

          2) If we have to daisy-chain multiple boards together, will we have to buy a control board for each evaluation board?

           

          Thank you for your help!

           

          Regards,

          Erika

          • 2. Re: CN0235: Fully Isolated Lithium Ion Battery Monitoring and Protection System
            JFitzger

            Hi Erika,

             

            The CN0235 Evaluation Board will allow you to monitor 12 batteries at once.  6 per AD7280A/AD8280 pair.

            I do not believe the board is setup so that multiple CN0235 evaluation boards can be daisy chained together.

             

            I believe you'll be able to do this with multiple CN0235 board if you also use multiple SDP-B boards.  It has not been tested this way and I'm not sure if this is safe or not.

             

            I have noticed that the AD7280A Evaluation Board provides pin headers to allow multiple AD7280A Evaluation Boards to be daisy chained together.  You might want to consider this.  It is more expensive and it uses the CED Board.

            • 3. Re: CN0235: Fully Isolated Lithium Ion Battery Monitoring and Protection System
              CatherineR

              Hi James, Erika,

              Yes, the AD7280A evaluation board allows for multiple boards to be connected in a daisy-chain, with one master and multiple slaves (max of 7 slaves connected).

               

              Only one interface/controller would be required to communicate to the Master AD7280 device, that master would then communicate in a daisy-chain fashion to the above devices.

               

              The evaluation boards come with software which supports a 2-board configuration, this supports 4 x AD7280A devices, which can measure a chain of 24. To measure higher channel counts, you would need to develop your own software to do this. The AD7280A evaluation board provides a header to give you access to the serial control lines in order to do this.

              Please take care when working with high voltage battery stacks.

               

              best regards,

              Catherine.