Wireless energy transfer for rechargeable batteries

An assembly configured to receive power wirelessly through an oscillating magnetic field generated by a wireless power source, the assembly comprising:na first resonator coil having a first characteristic size and configured to couple to a first electrical load; anda second resonator coil having a second characteristic size and positioned so that a minimum distance between the first resonator coil and the second resonator coil is less than half as large as a larger of the first and second characteristic sizes,wherein the second resonator coil is oriented with respect to the first resonator coil so that a value of a coupling parameter k between the first and second resonator coils is smaller by a factor of at least two than a maximum value of k for any orientation of the second resonator coil for the same minimum distance between the first and second resonator coils.

An apparatus for wireless energy transfer, comprising:na first member comprising:na first magnetic resonator configured to receive wireless energy via oscillating magnetic fields; anda first housing that at least partially encloses the first magnetic resonator and has a form factor that corresponds to a shape of a battery; anda second member comprising:na second magnetic resonator configured to receive wireless energy via oscillating magnetic fields; anda second housing that at least partially encloses the second magnetic resonator and has a form factor that corresponds to the form factor of the first housing,wherein the first resonator is positioned asymmetrically in the first housing; andwherein when the first and second members are positioned antiparallel at a distance d, a value of a coupling parameter k between the first and second magnetic resonators is less than 50% of a maximum value of k for any non-antiparallel positioning of the first and second members at the distance d.

A wireless battery system comprising a plurality of wireless batteries, each wireless battery comprising:na cylindrical enclosure, symmetrical around an axis, and comprising a first end and a second end with a positive terminal on the first end and a negative terminal on the second end; anda magnetic resonator configured to receive energy wirelessly through oscillating magnetic fields, the magnetic resonator comprising a plurality of loops of conductive material oriented coaxially with the symmetry axis of the enclosure,wherein the magnetic resonator is positioned asymmetrically along the symmetry axis with respect to the first and second ends; andwherein when any two of the wireless batteries are separated by a distance d and positioned such that their respective symmetry axes are parallel and the first end of one of the two wireless batteries is coplanar with the second end of the other of the two wireless batteries, a value of a coupling parameter k between the two wireless batteries is less than half of a maximum value of k for any orientation of the two wireless batteries at the distance d.