Pulse Applications of Electrochemical Cells - Materials Aspects

There is a rapidly increasing need for energy sources that are optimized to provide electrical energy at high power for short times. The terms "ultracapacitor" and "supercapacitor" are often used to describe some types of such devices. Applications include the requirement for very short pulses for digital electronic devices, the somewhat longer power pulse demands of heart defibrillators and other implantable medical devices, and the much larger transient power needs in connection with electric vehicle traction. The several mechanisms that can be used to store and provide pulse energy in electrochemical systems are reviewed. Their fundamental characteristics, as well as their applicability to the different types of pulse output requirements, are discussed. The use of spreadsheet techniques to model transient transport behavior in solids under various conditions, as well as the use of Laplace transform methods to convert information about the physical mechanisms and parameters of individual components into the dynamic response of an electrochemical system are demonstrated.