VS - Electrical Systems From Stop-Start to Hybridization

The battery sensor is a key contributor to improving battery reliability and electrical system integrity. Based on the State Of Charge calculation, appropriate actions can be launched to secure the energy level for the car and particularly for the Stop-Start repeated cranking demands. The Stop-Start function is enabled according the many parameters, the battery status being one of the major ones.

●● If the battery state of charge is too low (<75%) or if the temperature is under 0°C, the combustion engine is not stopped so that the alternator provides the energy to the whole electrical system. ●● If during a stop phase, the battery state of charge decreases too much, the engine is restarted. The following graph illustrates the history of voltage, current and calculated State Of Charge over a driving cycle on a Stop-Start application.

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500 State Of Charge (%) 68.5 69 69.5 70 70.5 71 500 Battery voltage (mV) 1.1 1.2 1.3 1.4 1.5

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Tracking the operational history to evaluate the actual condition of a battery is complicated due to the addition of measuring inaccuracies. To secure the calculation of the State Of Charge and avoid loss of prediction, it is mandatory to smartly manage the starting point of the processing by regularly re-synchronizing the calculation, one solution is to measure the battery Open-Circuit Voltage. The Open-Circuit Voltage is the voltage between the battery poles under no-load conditions.

Diversity Battery sensors are customized according to: ●● Battery technology (flooded, AGM…) ●● Battery size

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