High Power Electrochemical Energy Storage for Directed Energy Applications

The desire of the US Department of Defense (DoD) to field new directed energy systems for a variety of applications increases daily. This desire stems from recent advances in energy storage and solid-state switch technologies, which enable researchers to make systems more compact and energy dense than ever before. While some systems can draw power from the mobile platform on which they are mounted, other systems need to operate independent of a platform and must be completely self-sufficient. The transient and repetitive operation of these directed energy systems requires that the prime energy source provide high power to intermediate energy storage devices. The ability of electrochemical energy storage devices, such as lithium-ion batteries, to source high power quickly has previously been limited. However, battery manufacturers have recently produced cells that are more power dense then previously available. In addition to lithium-ion batteries (LIBs), researchers have greatly improved the capabilities of electric-double-layer capacitors (EDLCs) and lithium-ion capacitors (LICs) increasing their application space further as well. In order to experimentally validate the pulsed current cycling limitations of some of the newest electrochemical cells, a novel low impedance test stand has been developed. The total impedance of the stand, less than 1 milli-Ohm, is such that in most cases, the impedance of the cell dominates the charge/ discharge current. A description of the test stand will be given and experimental results will be presented to demonstrate the capabilities of those new power dense electrochemical energy storage technologies