A method of estimating an internal temperature of a vehicle battery is based
on
heat transfer between a heat source and the battery. In addition to the heat source,
airflow generated by vehicle movement and radiator fans affects the internal temperature
of the battery. The method estimates an initial internal temperature of the battery
at engine startup based on how long the engine was off. The temperature of the
heat source is determined. A transfer function is determined to represent the effect
of the airflow. The method updates a current internal temperature of the battery
based on the initial internal temperature and an integration of the transfer function
and the heat source temperature.
