US 9,812,877 B2
Charge redistribution method for cell arrays
Ioannis Milios, New York, NY (US)
Assigned to Sendyne Corporation, New York, NY (US)
Filed by Sendyne Corporation, New York, NY (US)
Filed on Feb. 18, 2015, as Appl. No. 14/625,270.
Application 13/926,057 is a division of application No. 13/510,935, abandoned, previously published as PCT/IB2011/054789, filed on Oct. 27, 2011.
Application 14/625,270 is a continuation of application No. 13/926,057, filed on Jun. 25, 2013, abandoned.
Claims priority of provisional application 61/408,505, filed on Oct. 29, 2010.
Prior Publication US 2015/0222133 A1, Aug. 6, 2015
Int. Cl. H02J 7/00 (2006.01); H01M 10/44 (2006.01)
CPC H02J 7/0021 (2013.01) [H01M 10/441 (2013.01); H02J 7/007 (2013.01); H02J 7/0014 (2013.01)] 5 Claims
OG exemplary drawing
 
1. A method for use with a series array of a plurality of electrochemical cells, each cell having a respective state of charge, the method comprising the steps of:
measuring discharge current during a first measurement interval, said current measurement during the first measurement interval carried out across a predetermined bandwidth;
measuring cell terminal voltage for a first one of the cells during the first measurement interval, said voltage measurement during the first measurement interval carried out across the predetermined bandwidth;
measuring discharge current during a second measurement interval, said current measurement during the second measurement interval carried out across a predetermined bandwidth;
measuring cell terminal voltage for a second one of the cells during the second measurement interval, said voltage measurement during the second measurement interval carried out across the predetermined bandwidth;
deriving information indicative of a respective effective internal impedance for each of the first one of the cells and the second one of the cells, said derived effective internal impedance having not only a pure ohmic component but also frequency dependent component, said derived effective internal impedance defining a magnitude greater than that of the pure ohmic component taken alone;
deriving information indicative of a respective effective internal cell voltage for each of the first one of the cells and the second one of the cells;
monitoring a signal frequency of a load current delivered by the series array of a plurality of electrochemical cells to a load;
determining a relationship between the signal frequency of the load current and the respective state of charge of each cell, and thereby identifying a particular one of the first one of the cells and the second one of the cells having a lower effective internal cell voltage and a higher magnitude of effective internal impedance; and
topping up the state of charge of the identified cell.