Field Battery Investigation – Part 2: Aging behavior

Summary:

The safe power supply is gaining in importance due to the increasing automation of vehicles and the resulting higher safety requirements. More safety-relevant consumers such as sensors and actuators for the safe control of the vehicle must be supplied via the low-voltage power supply system and require a minimum voltage to operate properly. This is provided with energy via the DCDC converter respectively from the 12 V battery. For the safety concept of the entire vehicle, the battery is an important component and requires more in-depth reliability analyses.

Therefore, the 12 V battery supply is investigated in this study with regard to its reliability and service life using the example of field-aged lead batteries. In addition to a functional diagnosis in the vehicle, the ageing and failure behavior of current battery types under real aging conditions is of interest to demonstrate reliability.

The electrical parameters from the battery characterization presented with the separate poster part 1 are related to their new condition and end-of-life criteria to quantify and compare the different aging progress of individual aging mechanisms and identify their dominant failure mode.

In addition, the voltage behavior of these differently aged batteries is investigated using the newly introduced safe-stop pulse. This safe-stop-pulse consists of a two-stage current profile, which reproduces a so called “safe-stop-maneuver” of future vehicles and shifts the focus from the pure high current demand to the provision of energy for a longer period of time. Thus, this evaluation aims at a safe energy supply for future driving applications and shows the voltage behavior during the “safe-stop-maneuver” for differently aged batteries.

Using this methodology presented in poster part 1 and 2, batteries from automotive workshops and road service are used to obtain an up-to-date picture of the lead battery in the field and show their potential in future driving applications. Moreover, these battery data can be used to carry out further reliability investigations.