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Autocycle function/Automatization of charge-discharge cycle repeatability

Davide Gheno
Prodigy 110 points
Other Parts Discussed in Thread: EV2400, BQ40Z50EVM-561

Goodmorning,

first of all, I'll briefly describe the test environment I implemented for Li-ion battery testing purpose. I'm currently using an EVM bq40Z50EVM-561 combined with EV2400 board. I need to test and characterize multiple battery types (single/multi cell, different chemistries) in order to compare them and choose the best battery fitting with my scopes.

The battery test procedure established involves repeating charge/discharge cycles up to 500 times. Before proceeding with the tests, I need to define the battery chemistry; for some battery types, the chemID is not available in the chemID list. I read in other conversations in this forum that the Li-ion battery manual procedure for the Data Log file and the Configuration file generation is the following:

1. Test is performed at room temperature. If the cell was at a different temperature , let the cell relax for two hours at room temperature prior to the test.

2. Charge using CC or CV charging to full using taper current. (For example, C/100.) Use nominal CC charge rate and CV voltage. If another charging method is specified by the cell maker, use that method.

3. Let the battery relax for two hours to reach full equilibrium open circuit voltage (OCV).

4. Discharge the battery at C/10 rate until the minimal voltage (as specified by the cell manufacturer) is reached.

5. Let the battery relax for five hours to reach full equilibrium OCV.

Unfortunately (or maybe not) my company is not normally open 24hrs... so, the first question is:

  • Is there an alternative automatic method in order to obtain the correct chemID for the battery under test?


The second question regards the possibility to set up an automatic method in order to run the 500 times cycles automatically. I've read in the forum that the Autocycle option is not yet available for the current TI products.. but I cannot understand the usefulness of your product is if I can't repeat time-expensive tests automatically... so, the second question is:

  • With the test environment currently available to me, is there a method to automate repeatability (about 500 times) of cycles? Or do you expect an upgrade that allows the use of Autocycle function? If yes, can you provide a time estimation for the upgrade?

I also read that exist the Gauge Development Kit (GDK). From what stated in the product description, the GDK features also include:

  1. Automated Learning Cycles;
  2. Automated cycling with customizable profiles.

Could these features meet my needs? However, the GDK product description declares some limitations that are blocking for me:

  1. Max charge/discharge current 2A;
  2. GDK is applicable only for any SINGLE-CELL fuel gauge.

So, the third question is:

  • Do you expect any upgrade for the GDK product that could resolve the limitations listed above? If yes, can you provide a time estimation for the upgrade? Or, in any case, is there any other product that could fit with my needs?

Thanks in advance

Davide

  • 0
    TI__Mastermind 42535 points

    1. No, unfortunately this is the only way to obtain a chem ID match. You don't have to exactly stop the dsg at 10 hours, you can continue logging and trim the log later.

    2. Autocycle was a planned feature that is in the to do list. We don't have a time line as to when it will be completed. You can certainly use programmable power supplies

    3. The gdk was a standalone for a 1s gauge. We don't expect to change it.

    The one suggestion I can give you is to use a programmable supply and load and pair it up with a PC for logging. That way you can configure it for your needs.