Design And Function: Vibrations
WARNING: This page is about a different car, the 2004 Volvo S40, 2003 Volvo S40, 2002 Volvo S40, 2001 Volvo S40, and 2000 Volvo S40. However, it is still accessible from the selected car via links, so may be relevant.
The battery is subjected to vibrations if the car is driven on uneven surfaces. Such vibrations can place stress on the inner connections in the battery and cell units, resulting in wear and damage to the battery. This is a rare occurrence in modern cars however.