Cooling the High-Voltage Battery

Cooling the high-voltage battery

The high-voltage battery reaches maximum power of 38 kW within a temperature range of +50° F. (10° C.) to +99° F. (37° C).







The protected installation position of the battery prevents lower temperatures in practice. If the temperature is still below the minimum threshold, warming pulses are generated through the cyclic application of charge and discharge currents until the temperature reaches the +50° F. (10° C.) threshold. Consequently, Start Stop mode can be activated for the combustion engine after 15 minutes, even if the vehicle is extremely cool throughout.

When the battery is charged and discharged, resistance develops inside the battery and generates heat that must be dissipated in order to prevent the chemicals in the cells from degrading throughout the service life of the vehicle.

NOTE: The opening in the supply air duct under the rear seats must remain unobstructed so that enough air can be drawn in to cool the battery sufficiently.

Air is drawn from the passenger compartment to cool the battery. The two fans attached to the rear end of the battery housing draw conditioned air directly from the rear passenger compartment and through the battery in order to regulate the battery temperature. The fan control is synchronized in line with the vehicle speed and is hardly audible for the vehicle occupants.







The aspirated air escapes through openings (forced-air ventilation through plastic slats) in the underbody of the luggage compartment. The battery manager (BMS) monitors regulation of the battery cooling system.

The driver is still responsible for regulating the air conditioning. If the cabin is too warm, the operating strategies are modified in succession to restrict the charging and discharging currents and prevent the temperature from increasing further. As illustrated in the diagram, the charging currents are initially limited to 6 A at 99° F. (37° C.) and recuperation is then reduced if the temperature continues to rise. A reduction in boosting and electric operation also limits discharging accordingly.