11
Pack Assembly and The bq20z95
CELL 4
+
-
CELL 3
+
-
CELL 2
+
-
CELL 1
+
-
1N
1P
2P
3P
4P
EVM
Connector
Battery
Stack
Pack Assembly and The bq20z95
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This section describes a recommended assembly sequence for a bq20z95-based battery pack. This
procedure results in the most time-efficient setup of the battery pack. Following are the steps for
connecting a 4-series cell battery to the bq20z95EVM board. Review the application report
bq20zxx EVM
Data Flash Settings for Number of Serial Cells and Pack Capacity
,
SLVA208
, for further details on 2- and
3-series cell arrangements.
Figure 12. Connection Sequence
1. Connect the most negative terminal (– terminal of cell 1) of the serially-connected, 4-cell battery stack
to the 1N PIN of the TB3–TB2 connector as shown in
Figure 12
.
2. Connect the positive terminal of cell 1 to 1P.
3. Connect the positive terminal of cell 2 to 2P.
4. Connect the positive terminal of cell 3 to 3P.
5. Connect the positive terminal of the battery stack (+) to 4P.
6. Connect external power (from 6 to 16.8V) to the Pack+ and Pack– terminals to wake up the EVM from
shutdown mode. External power does not need to remain connected once the bq20zxx has exited
Shutdown Mode.
7. Connect the SMBus connector (J1) to the EV2300 adapter and start the EV software.
8. Navigate to the
Flash Screen
. Change the flash constants that correspond to the specific parameters
of your application (refer to the data sheet or other application reports). For the first evaluation, the
default values may be used.
9. Navigate to the
Calibration screen
. Select the check-box for
CC Offset Calibration
. Click the
calibrate
part
button. It should show OK.
10. Uncheck previously-selected boxes. Select the check-box for voltage near
Measured voltage
field.
Measure the actual pack voltage between pins 1N and 4P, and enter the value into the
Enter actual
voltage
field. Click the
calibrate part
button.
11. To start fuel-gauging, navigate to the
Pro screen
in the EV software. Make sure that the
Write SMB
Word
section reads: "SMB Command: 00 Word (hex): 0021" as shown in
Figure 13
, and click the
Write
button.
Figure 13. Fuel Gauging Command
12. Navigate to the SMB Screen and be sure that the QEN bit in Operation Status is set (red). The
Relative State of Charge
value is now updated to the correct value that corresponding to the state of
charge of the attached cells.
13. Now the pack is ready. Simulate insertion into a system by shorting between the
Sys Pres
(System
Present) and the
VSS
pins on the connector. At this point, the discharge and charge FETs are ON (as
indicated by value of 0006 in the
FET Status
field in the SMB Screen of the EV software), and
charge/discharge tests can be conducted. This step in not needed if the NR bit (nonremovable pack) is
enabled in Operation Cfg B register.
16
bq20z95EVM-001 SBS 1.1 Impedance Track™ Technology
SLUU275 – October 2006
Enabled Battery Management Solution Evaluation Module
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