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bq78PL114 cell chemistry file

Zoran Mihajlovic
Prodigy 60 points
Other Parts Discussed in Thread: BQ78PL114, BQ78PL116, BQ27541

As we’re starting to take a closer look at the bq78PL114 EVM and develop our own custom board simultaneously, there are some questions that came up regarding the cell chemistry file.  Namely, we are going to be working with a LiFePO4 cell, 5Ah 32650, but since there is no cell chemistry file that matches the above cell (nor manufacturer) we are ready to work with TI on getting one created.  Would you be able to help me with this one or direct me to the right person at TI?

Thank you in advance.

 

 

  • 0
    TI__Expert 7025 points

    Zoran,

    Thanks a lot for your post. I'm going to help support you moving forward.

    Have you taken a look at the BQ78PL116? This is the updated version of the BQ78PL114 and should be used for new designs.

    The standard next step for determining a pack chemistry is to put the pack through a bqEASY learning cycle. bqEASY will automate the chemistry detection process and estimate the closest matching chemistry ID.

    We want to explore this avenue fully before we move on to more complicated chemistry analysis methods.

    I have more details on the bqEASY process coming shortly.

    Tyler

  • 0 in reply to Tyler Pate
    Prodigy 60 points

    Thank you Tyler. 

    Is it going to be possible to run bqEASY using a bq78PL114 EVM?  Didn't want to jump the gun, but needed to ask, as this is the only hardware that we have avaialble right now.

    Thanks,
    Zoran

     

  • 0 in reply to Zoran Mihajlovic
    TI__Expert 7025 points

    Zoran,

    I've gotten some updated information about the chemistry learning process and have some updates for you.

    First, the bqEASY method is no longer reccomneded. The algorithm uses a limited number of data points and has been replaced by a newer algorithm.

    The C/10 algorithm is implemented with our impedance track gas gauges, and requires an EVM such as the bq27541. This uses a single cell to determine the battery chemistry.

    Do you have access to a single cell from the pack to use for chemistry testing? If so, I'll go ahead and order you the EVM necessary to complete the chemistry ID. I have an e-mail with explicit directions on how to perform the C/10 method that I will also forward to you.

    Do you need help getting a bq78PL116 EVM?

    Thanks,

    Tyler

     

     

  • 0 in reply to Tyler Pate
    Prodigy 60 points

    Tyler,

    Yes, I have access to a single cell from the battery pack that we need characterized, and I would appreciate your help with the necessary EVMs (bq27541 and bq78PL116). 

    Thanks a lot.

  • 0 in reply to Zoran Mihajlovic
    TI__Expert 7025 points

    Your EVMs have been ordered, and I in the process of sending you the requested e-mail detailing the C/10 process.

    If you have any specific support questions about the process, please use this thread for the dialogue.

    Tyler

     

  • 0 in reply to Tyler Pate
    Prodigy 60 points

    Thanks again.

    Will do.

  • 0 in reply to Tyler Pate
    Prodigy 150 points

    Mr. Tyler , 

    In our application , we want to balance 16 serial modules and each module has 8 parallel 5.1Ah li-po cells . We are using bq78pl116 but do not have proper equipment  to do the required tests(0.5C,0.7C charge/discharge) mentioned in slua505- "chemistry selection for bq78pl114" , for generating an auxiliary file and to choose chem typle of the cells.

    Is there any way to do the tests in a reduced amount of C, or to only test for 3 or 4 serial modules and then apply the results somehow  for the 16 serial modules?

  • 0 in reply to Tyler Pate
    Prodigy 120 points

    Tyler,

    Is the C/10 algorithm you refer to published anywhere as an app note, or other?  Can you send it to me or provide a link?

    Thanks,

    David