Wirelessly rechargeable battery and power transmitter
A wirelessly rechargeable battery is provided having coils oriented off major battery axes to facilitate good coupling with power transmitter magnetic fields. A magnetic core may house charging electronics for a compact form factor. A wireless power transmitter that produces fields to maximize coupling with receiver coils.
1. A wirelessly rechargeable battery comprising:
a. an elongate battery casing having a longitudinal axis;
b. a rechargeable storage device;
c. a plurality of power receiving coils disposed at an angle of between 30 to 60 degrees to the longitudinal axis; and
d. a charging circuit for controlling the supply of power from the coils to the storage device.
2. A battery as claimed in claim 1 wherein the receiving coils are disposed at an angle of about 45 degrees to the longitudinal axis.
3. A battery as claimed in claim 1 having two coils.
4. A battery as claimed in claim 3 wherein the coils are substantially orthogonal.
5. A battery as claimed in claim 1 having three coils.
6. A battery as claimed in claim 5 wherein the coils are oriented at about 60 degrees to each other.
7. A battery as claimed in claim 1 wherein the charging circuit provides resonant circuit tuning.
8. A battery as claimed in claim 7 wherein the charging circuit provides resonant circuit tuning by way of series tuning compensation.
9. A battery as claimed in claim 7 wherein the charging circuit provides resonant circuit tuning by way of a semiconductor operating in linear mode.
10. A battery as claimed in claim 1 wherein the coils are wound about a magnetic core.
11. A battery as claimed in claim 10 wherein the magnetic core has a cavity to at least partially house the charging circuit.
12. A battery as claimed in claim 11 wherein the charging circuit is entirely housed within the cavity in the core.
13. A wirelessly rechargeable battery comprising:
a. a battery casing;
b. a rechargeable storage device;
c. one or more power receiving coils mounted on a ferrite core; and
d. a charging circuit for controlling the supply of power from the coils to the storage device, wherein at least one of the charging circuit and the storage device is at least partially housed within the ferrite core.