Battery System Monitoring
7. Battery system monitoring7.1 battery over temperature monitoring(P0A7E)
7.1.1 Monitoring strategy
This monitoring strategy will check, if the battery temperature exceeds the critical battery temperature threshold (see Figure 7-1).
If one temperature (Th1...Th8, outlet temperature) sensor exceeds the critical battery temperature threshold a malfunction is detected.
7.1.2 Enable conditions
7.1.3 Chart(s) and flowchart(s)
7.2 Battery state of charge monitoring (P0C30, P0B25)
The battery calculates the state of charge by using current, block voltage and battery temperature.
7.2.1 Monitoring strategy
This monitoring strategy will check, if the state of charge value exceeds an upper (over charged) or lower (deep discharged) threshold (see Figure 7-3).
7.2.2 Enable conditions
7.2.3 Chart(s) and flowchart(s)
7.3 Battery low voltage monitoring (P0A7D)
7.3.1 Monitoring strategy
This monitoring strategy will check, if the battery is deep discharged by voltage measurement.
There are two criteria to detect a deep discharged battery by voltage measurement.
At first the open contactor block voltage (OCV) is checked. If at least one open contactor block voltage falls below a minimum threshold depend on battery temperature, a malfunction is detected (see Figure 7-5).
At second the strategy checks the block voltages during cranking the combustion engine.
If the pack voltage or at least one block voltage falls below the deep discharge voltage threshold, also a malfunction is detected (see Figure 7-5).
7.3.2 Enable conditions
7.3.3 Chart(s) and flowchart(s)
7.4 Battery pack voltage monitoring (P0AFB, P0AFA)
7.4.1 Monitoring strategy
This monitoring strategy will check, if the pack voltage value exceeds an upper or lower voltage threshold (see Figure 7-7).
7.4.2 Enable conditions
7.4.3 Chart(s) and flowchart(s)
7.5 Battery block voltage deviation monitoring (P0B3C, P0B41, P0B46, P0B4B, P0B50, P0B55, P0B5A, P0B5F, P0B69, P0B6E, P0B73, P0B78, P0B7D, P0B82, P0B87, P0B8C)
7.5.1 Monitoring strategy
This monitoring strategy will check, if one block voltage value differs to the average block voltage.
If the voltage difference exceeds a threshold, a malfunction is detected (see Figure 7-9).
7.5.2 Enable conditions
7.5.3 Chart(s) and flowchart(s)
7.6 Battery HV short circuit (P0AF8)
7.6.1 Monitoring strategy
This monitoring strategy will check, if there is a shortage in HV wiring.
The first check is done during precharge, if the battery current exceeds an upper current threshold.
The second check is done after contactors (positive / negative) are closed. A malfunction is detected, if the all battery pack voltage measurements fall below a voltage threshold.
7.6.2 Enable conditions
7.6.3 Chart(s) and flowchart(s)
7.7 Battery less performance monitoring (P0A80)
7.7.1 Monitoring strategy
This monitoring strategy will check, if the battery is deteriorated.
The less performance check is done by evaluating the internal resistance of the battery.
The Ri is calculated within following boundary condition.
- battery temperature range
- battery voltage range
- battery current range
The Ri is calculated if the battery load is in between the green zone (normal load) for a defined time range (see Figure 7-14). Also the load ) has to exceeded the blue zone (high load) in both directions within the defined time range. Measurements in between the yellow- (no load zone) and the orange zone (overload zone) would not be taken to calculate the Ri.
If the Ri calculation conditions and the fault conditions (see Figure 7-15) are satisfied a less performance counter is incremented.
The less performance counter is reset, if the internal resistance is below threshold.
If the less performance counter exceeds a threshold, a malfunction is qualified.
7.7.2 Enable conditions
7.7.3 Chart(s) and flowchart(s)
