US 7,531,256 B2
Energy storage system
Bart D. Hibbs, Altadena, Calif. (US); William M. Parks, Simi Valley, Calif. (US); and Omourtag A. Velev, La Crescenta, Calif. (US)
Assigned to Aerovironment Inc., Monrovia, Calif. (US)
Filed on Oct. 31, 2007, as Appl. No. 11/981,200.
Application 11/981200 is a division of application No. 10/418737, filed on Apr. 17, 2003.
Claims priority of provisional application 60/373301, filed on Apr. 17, 2002.
Prior Publication US 2008/0187809 A1, Aug. 07, 2008
Int. Cl. H01M 8/04 (2006.01); H01M 8/18 (2006.01)
U.S. Cl. 429—20  [429/21; 429/26] 2 Claims
OG exemplary drawing
 
1. A closed loop energy storage system comprising:
a fuel cell stack configured to react a gaseous fuel with a gaseous oxidizer to produce a liquid product and electrical power;
an electrolyzer stack configured to separate the product into a first mixture including the liquid product and the gaseous fuel, and a second mixture including the liquid product and the gaseous oxidizer;
a first phase separator configured to separate the liquid product from the first mixture to produce gaseous fuel;
a second phase separator configured to separate the liquid product from the second mixture to produce gaseous oxidizer;
a fuel tank configured to store gaseous fuel for subsequent reaction in the fuel cell stack; and
an oxidizer tank configured to store gaseous oxidizer for subsequent reaction in the fuel cell stack;
wherein at least one of the phase separators is configured to receive liquid product from the fuel cell stack and store the liquid product for subsequent separation in the electrolyzer stack, without the use of a separate storage tank for the liquid product.