US 11,936,228 B2
Battery charger
William Rigdon, Baltimore, MD (US); Lisa M. King, Towson, MD (US); Bhanuprasad V. Gorti, Perry Hall, MD (US); Brian K. Wohltmann, Shrewsbury, PA (US); Hussein M. Nosair, Parkville, MD (US); and Michael Muilwyk, Felton, PA (US)
Assigned to BLACK & DECKER INC., New Britain, CT (US)
Filed by Black & Decker Inc., New Britain, CT (US)
Filed on Jun. 15, 2021, as Appl. No. 17/348,357.
Claims priority of provisional application 63/039,561, filed on Jun. 16, 2020.
Prior Publication US 2021/0391741 A1, Dec. 16, 2021
Int. Cl. H02J 7/00 (2006.01); H02J 7/02 (2016.01)
CPC H02J 7/00712 (2020.01) [H02J 7/0013 (2013.01); H02J 7/0047 (2013.01); H02J 7/02 (2013.01)] 29 Claims
OG exemplary drawing
 
1. A battery charger, comprising:
an AC impedance circuit to apply a sinusoidal AC excitation signal to a connected battery pack and to measure a battery pack response to the sinusoidal AC excitation signal;
a charger controller including first circuitry to (1) calculate an impedance value of the connected battery pack based on the sinusoidal AC excitation signal and the battery pack response and (2) select a charging scheme based on the impedance value of the connected battery pack;
a power supply including second circuitry to provide the charging scheme selected by the charger controller, wherein:
the sinusoidal AC excitation signal is applied prior to and separate from the charging scheme being provided, and
the charging scheme is provided after the sinusoidal AC excitation signal is applied; and
when the charger controller selects a maximum charging rate charging scheme, the charger controller applies a constant current with a variable termination voltage based on a magnitude of the impedance value of the connected battery pack when the sinusoidal AC excitation signal is set to a value that produces a positive phase shift.