Patents Assigned to Squirrel Holding Ltd.
  • Patent number: 7046531
    Abstract: A static inverter for a battery of elementary, current sources or cells electrically in series and a number N of intermediate voltage taps along the chain of elementary DC current sources, wherein the number of elementary cells comprised between an intermediate tap and another intermediate tap adjacent to it or an end terminal of said chain is proportionate to the amplitude in the respective phase interval of a number N of discretization phases of the waveform of the AC voltage to be output in a quadrant; is implemented by arranging for: a number N of power switches each connecting a respective intermediate tap and a first end terminal of a first polarity of said chain of elementary cells in series to a common circuit node of said first polarity; an output bridge stage constituted by at least four power switches controlled in pairs for switching the current paths through the bridge stage, having a first pair of nodes coupled to said common circuit node of said first plurality and to the other end terminal of
    Type: Grant
    Filed: January 12, 2004
    Date of Patent: May 16, 2006
    Assignee: Squirrel Holdings Ltd.
    Inventors: Andrea Zocchi, Placido M. Spaziante, Krisada Kampanatsanyakorn
  • Patent number: 6905797
    Abstract: A multicell assembly for a redox flow electrolyzer is constituted by alternately stacking pre-assembled elements, typically an electrode subassembly including porous mat electrodes on opposite faces of a conductive plate and a permionic membrane subassembly. Pressure drops in circulating the electrolyte solutions through respective cell compartments, in contact with fluid permeable three-dimensional electrodes in the form of porous mats, are reduced while enhancing evenness of electrolyte refreshing over the whole geometrical cell-area, by defining cooperatively interleaved flow channels in the porous mat electrode. Two interleaved orders of parallel flow channels are defined. All the parallel spaced channels of each order extend from a common orthogonal base channel formed along the respective inlet or outlet side of the electrolyte flow chamber, and terminate short of reaching the base channel of the other.
    Type: Grant
    Filed: December 4, 2002
    Date of Patent: June 14, 2005
    Assignee: Squirrel Holdings Ltd.
    Inventors: Barry M. Broman, Andrea Zocchi
  • Patent number: 6692862
    Abstract: By realizing or installing check valve liquid vein interrupters in each compartment of the battery the phenomenon of slow discharge of the retained volumes of electrolytes during long periods of inactivity of a redox flow battery, with the electrolyte pumps stopped altogether, can be practically eliminated with the effect that the battery is perfectly ready to deliver electric power immediately upon request even after prolonged periods of inactivity. Moreover, the presence of liquid vein interrupters on each compartment in either an outlet or an inlet port substantially preventing by-pass current during a not pumping phase, permits to increase the by pumping the electrolytes through the compartments of a battery stack intermittently, in other words in a pulsed manner, with a certain duty-cycle.
    Type: Grant
    Filed: November 30, 2001
    Date of Patent: February 17, 2004
    Assignee: Squirrel Holdings Ltd.
    Inventor: Andrea Zocchi
  • Patent number: 6555267
    Abstract: A multicell assembly is constituted by alternately stacking two types of pre-assembled elements: a bipolar electrode holding subassembly and a membrane holding subassembly. The alternate stack of elements is piled over a bottom end element and the stack is terminated by placing over the last membrane holding element a top end electrode element.
    Type: Grant
    Filed: April 12, 2001
    Date of Patent: April 29, 2003
    Assignee: Squirrel Holding Ltd.
    Inventors: Barry Michael Broman, Andrea Zocchi
  • Patent number: 6475661
    Abstract: A redox flow battery composed of a plurality of cells in electrical series defined by a stacked and repetitive arrangement of a conductive intercell separator having a generally bipolar function, a positive electrode, an ion exchange membrane, a negative electrode and another conductive intercell separator, is operated by flowing a positive half-cell electrolyte containing reducible and oxidizable ions of a first redox couple through the compartments containing the positive electrodes and a negative half-cell electrolyte containing reducible and oxidizable ions of a second redox couple through the compartments containing the negative electrodes in cascade in a counter or equi-current mode. The difference of cell voltage between the first and the last cell of the stack is sensibly reduced and by-pass currents are substantially eliminated thus resulting in an increased overall faradic efficiency.
    Type: Grant
    Filed: April 24, 2000
    Date of Patent: November 5, 2002
    Assignee: Squirrel Holdings Ltd
    Inventors: Alberto Pellegri, Barry Michael Broman
  • Patent number: 6296746
    Abstract: Carbon-base bipolar electrode for electrochemical redox reactions in an acid electrolyte in the form of a fluid impervious and electrically conductive septum, at least a face of which consists, at least partially, of a fluid previous woven or unwoven electrodically active fabric of carbon fibers or of yarns of carbon fibers, has an electrically conductive fluid impervious septum consisting of a composite of a matrix fabric in the form of a tightly knit or woven fabric of carbon fibers or of yarns of carbon fibers the pores of which are hydraulically sealed by an electrically conductive carbon containing material at least partly filling the pores of said matrix fabric.
    Type: Grant
    Filed: April 19, 2000
    Date of Patent: October 2, 2001
    Assignee: Squirrel Holdings Ltd.
    Inventors: Barry Michael Broman, Andrea Zocchi, Alberto Pellegri