In-Vehicle and Lab Tests of State-of-Power Monitoring System for Automotive Batteries 2001-01-3344

All the electrical based systems and equipment of a vehicle depends, in last case, of a small but important device called battery. Understand and predict battery behaviour is one old target of the automotive manufacturers for different reasons like safety, comfort, fuel economy, etc… The paper will show the working-line and tests results of Lear, Seat and UB to achieve a method for monitoring the state of health and state of charge of battery life. There are some difficulties for in-vehicle battery monitoring: wide range of current levels, interference due to loads powered on, hard climatic conditions, high tolerances in battery manufacturing, among others.

Some of the methods for battery monitoring evaluated so far have been: Coulomb counting, Impedance spectroscopy, PH measuring, etc… For low cost on-line automotive applications the solution that could provide better results is based on impedance spectroscopy due to two main reasons: may be integrated into power management system of the vehicle, also optionally into the battery, and an historic profile is unnecessary for well running.

Firsts prototypes confirm initial expectations and after some studies carried out on different vehicles, such a spectrum analysis of power distribution bus, battery life cycle tests and temperature influence, shows the viability of system developed.