Pulsed Elevated Rate Discharge of Electrochemical Energy Storage Devices

Abstract

A number of electrochemical energy storage devices have been developed and used widely to power portable applications. Lithium-ion batteries are extremely popular for use in portable devices as a result of their high energy density. Despite their high energy density, most commercial off-the-shelf cells are only modestly power dense, limiting them from being used to drive high power or pulsed power applications. Recently, new high power lithium-ion battery technologies such as the Saft VL5U cell have been developed, which are not readily available off the shelf, with power densities as high as 28.5 kW/kg [1] that are an attractive means for driving pulsed power systems. Additionally, advanced energy storage capacitors, such as electric double layer capacitors and lithium-ion capacitors, have been developed with high energy and power densities that also make them a suitable candidate for use in pulsed power applications. Previous research using these types of devices in applications other than as storage in hybrid electric vehicles and renewable energy platforms has been limited. The University of Texas at Arlington is currently engaged in research to understand the limitations of these types of devices and to understand their future potential for use in pulsed high current experiments. A test stand, similar to that of Chen [2], but with a higher electrical action capability, has been developed and used to further characterize the performance of these types of devices when they are discharged at rates 10's to 100's of times their rated C values in pulsed fashion. This paper describes the rationale behind the experiments, the experimental setup developed, and the research progress made thus far.