US 12,408,240 B2
Inductive heating for cold weather charging
Andrew J. Spaulding, Racine, WI (US); and Kyle C. Fassbender, Brookfield, WI (US)
Assigned to Milwaukee Electric Tool Corporation, Brookfield, WI (US)
Filed by MILWAUKEE ELECTRIC TOOL CORPORATION, Brookfield, WI (US)
Filed on Nov. 30, 2021, as Appl. No. 17/538,459.
Claims priority of provisional application 63/119,918, filed on Dec. 1, 2020.
Prior Publication US 2022/0174794 A1, Jun. 2, 2022
Int. Cl. H05B 6/14 (2006.01); H01M 10/615 (2014.01); H01M 10/6235 (2014.01); H05B 6/10 (2006.01); H01F 38/14 (2006.01); H01M 10/48 (2006.01); H01M 10/6571 (2014.01); H02J 50/12 (2016.01)
CPC H05B 6/14 (2013.01) [H01M 10/615 (2015.04); H01M 10/6235 (2015.04); H05B 6/105 (2013.01); H01F 38/14 (2013.01); H01M 10/486 (2013.01); H01M 10/6571 (2015.04); H02J 50/12 (2016.02)] 20 Claims
OG exemplary drawing
 
1. An inductive heater assembly for heating a power tool battery pack, the inductive heater assembly comprising:
a housing;
a battery pack interface configured to receive the power tool battery pack;
a coil portion located within the housing, the coil portion including:
a first coil winding and a second coil winding configured to generate an electromagnetic field,
wherein the first coil winding and the second coil winding to form a Helmholtz coil;
a first switch electrically connected between a resonator circuit and an input of the first coil winding, the first switch configured to provide a first operating frequency to the first coil winding; and
a second switch electrically connected between the resonator circuit and an input of the second coil winding, the second switch configured to provide a second operating frequency to the second coil winding.