Hybrid Aerocapacitor{trademark}-battery power sources

PolyStor, Power-One, LLNL and Aerojet are participants in a Technology Reinvestment Program contract supported by the Advanced Research Project Agency for developing carbon aerogel-based Electrolytic Double Layer Capacitors (Aerocapacitors). This paper reports some recent results for organic-electrolyte Aerocapacitors developed under this contract and initial results on their use in electrolytic double layer capacitor (EDLC)-battery power sources. EDLC-battery hybrid power sources offer the potential for increased discharge time, improved low temperature performance and longer cycle life vis-a-vis batteries in pulse discharge applications. The authors previously presented performance results for AA Aerocapacitors but this is the first report of their work on hybrid power sources. Prototype organic-electrolyte Aerocapacitors exhibit low equivalent series resistance (ESR), high capacitance, excellent rate capability at room temperature and low temperatures, and long life. The AA-size devices assembled for testing have ESRs of 20-30 m{Omega} at 1000 Hz and capacitances of about 6 Farads. They are capable of being discharged at very high rates. The capacity at 15 Amps is about 71% of the capacity at 1 Amp. The capacity at 1 Amp and {minus}40{degrees}C is 57% of the room-temperature 1 Amp capacity. AA Aerocapacitors have demonstrated 32,000 cycles in cycle life testing. After an initial capacity decrease of about 17% the capacity remained almost constant between cycle 10,000 and cycle 32,000