2021 Audi S7 Sportback Hybrid High Voltage Battery Replacement Cost

Hybrid vehicles which use internal combustion engines (ICE) and electronic motors must have a storage location for electricity when it is not being used to propel the vehicle. Whether the system uses the ICE and brakes to charge the battery or a combination of the brakes and a power plug, the high voltage electrical battery is necessary to store the high voltage needed to run the large electric motor.

High voltage hybrid batteries are a combination of many individual battery cells. These battery cells are not powerful enough to power a large electrical motor like a hybrid drive motor, but many of these cells put together can drive the hybrid drive electric motor for many miles before needed to be recharged. As the vehicle is driven, the ICE will not only power the wheels, but it will generate electricity for the hybrid drive motor and store it in the hybrid high voltage battery. Also, when slowing down, regenerative braking will develop more power to be stored as electricity in the hybrid high voltage battery. When there is a demand for power, the high voltage battery will discharge into the hybrid drive motor, and this propels the wheels of the vehicle just as the ICE would. In essence, it works as a fuel tank for electricity.

Hybrid high voltage batteries most commonly fail as a result of memory or one or more bad cells. When batteries fail due to memory or degradation of cells the vehicle will loose efficiency (as rated in MPGe). This is because the battery can no longer propel the vehicle with as much energy or for as long as it was previously capable. In some cases, the service hybrid battery (or similar) warning light will display, and the vehicle may no longer be able to drive as an electric vehicle, or even support the ICE with hybrid power. In the worst cases, the vehicle may be completely disabled, even though the 12-volt electronics still function.