BQ34110: State of Health

Hi Phocas,

Prior to programming the devices with a DFFS file in production, these are the general steps that need to completed with some detailed sub-steps.  These steps will require an engineer to use bqStudio to create and test the device ‘Image’ SREC file prior to making the master ‘Golden Image’ SREC (and DFFS output as well).  Some steps may seem to be duplicated (such as a possible double calibration) – this is to ensure the steps work for most usage scenarios for a general purpose board.  These steps are not exhaustive and are for illustrative purposes only.  If you have any questions, please let me know.

1. Setting up the toolchain
   1. Acquire bq34110 EVM
   2. Acquire EV2400
   3. Download and install latest version of bqStudio (BQSTUDIOTEST on website)
   4. Download and install chemistry updater for bqStudio
   5. Lab Setup
      1. Lab Bench Power Supply (or Keithley)
      2. Multimeter
      3. Electronic load (or Keithley)
      4. Environmental Chamber
2. Initial EVM Bring up
   1. Connect EV2400
   2. Power the device as a single cell (default settings) by applying 4.5 V with Power Supply
   3. Ensure Jumpers are set for < 5V Operation
   4. Launch bqStudio
3. Calibrate the Board using BqStudio
   1. CC Offset and Board Offset
      1. No load
   2. Voltage
      1. Measure voltage with multimeter across bat- and bat+
   3. Current
      1. Apply 1 A load with electronic load across bat + and pack -, as shown in EVM User’s guide
4. Characterization of the Cell(s)
   1. The GPCCEDV tool on the TI Website will be utilized to determine the gauging parameters for the CEDV Gauge.  This will require the creation of 6 logs using bqStudio and will output values needed to program data flash for the gauge.
   2. Modify the data memory values to reflect the cell to be used for characterization.  For example, a series of cells such as a 12 V LA battery (which includes 6 cells, 6s1p).  Settings to be adjusted include, but are not limited to:
      1. Flash Update OK Voltage
      2. Number of Series Cells
      3. Modify all litihium-ion default cell values to reflect the cell values of a lead acid cell.  Settings in the device are per-cell.
   3. As the voltage required for the cells (6s1p) will be larger than 5 V and require a modification of Hardware, please:
      1. reconfigure the data memory for external voltage divider operation including
         1. Series value
         2. VEN = 1
      2. remove power from the EVM
      3. reconfigure both the external divider jumpers for 16 V max operation and jumpers for > 5 V operation
      4. power the board with 4.5 V       
      5. restart bqStudio
      6. Slowly increase the voltage to your stack voltage, e.g.,12 V for a 12 V battery stack
      7. Perform Calibration Step 3 above again to adjust to calibrate for new Hardware settings
      8. Ensure voltage and current are being reported properly
   4. Collect logs for the GPCCEDV Tool per the instructions found with the GPCCEDV tool
      1. Log Collection Device Setup
         1. Attach recommended thermistor to battery and connect to EVM
         2. Connect battery to EVM
         3. Place battery + EVM in temp chamber
         4. Connect load and power supply
            1. If the GPC Cycle tool in BqStudio is used to automate the collection of the 6 logs
               1. Connect external relays in line with the power supply and electronic load as described in the EVM User Guide and BqStudio
               2. Connect EV2400 pins to relays
            1. 1. 1. Set Termination Voltage
                  2. Set load pin
                  3. Set control pin
      2. The logs will be at the Normal Load and Max load the device should operate at 3 different temperatures.
   5. Submit logs to GPCCEDV tool
   6. Receive settings back from GPCCEDV tool via e-mail
5. Programming the Data flash
   1. Use bqStudio, the EVM, and a power supply to bring up the device
   2. Modify the data parameters to per cell values for the cell
   3. Modify gauge settings as preferred
   4. Modify the Gas Gauging parameters to include the information returned by the GPCCEDV tool
   5. Export SREC and GG.CSV file
6. Test device functionality and gauging accuracy
   1. RESET device
   2. Ensure device reports values as described in section 2.7.10 of TRM
   3. Create log during test
   4. Export SREC and GG.CSV file after test

 When creating the ‘golden image’, 10-30 production boards should be used and the values averaged between the boards.  Take the SREC from step 5 and  If the variance is low, the averaged calibration values may be utilized in the ‘golden image’ so calibration does not need to be performed during production.  When creating the ‘golden image’ also ensure to reset cycle and lifetime values.

For more information on these steps, please refer to the EVM User's Guide and the TRM.

Sincerely,

Bryan Kahler