The state of the art in battery management systems is based on heuristic algorithms or equivalent circuit models. While adequate, they cannot predict actual power limitations due to electrochemical constraints such as plating and aging phenomena. The actual causes of aging are the electrochemical and mechanical processes occurring within the cell: the cell’s terminal voltage is a poor but measurable indicator of the state of these processes. As a result, the state of health of a battery pack is inaccurately known.

The temperature at which power electronic systems operate is one the most important parameters for system reliability, especially for automotive applications. In today’s systems, the temperature of the power stage is measured by an NTC (Negative Temperature Coefficient) resistance which has limited accuracy and very slow dynamic response compared to the actual junction temperature swing inside the power devices. This lack of accuracy and responsiveness severely limits the ability to estimate die temperatures.