WO2019051026A2

WO2019051026A2 - Wireless charging systems and methods

Info

Publication number: WO2019051026A2
Application number: PCT/US2018/049665
Authority: WO
Inventors: Joshua Duffy; Matthew FLEENOR
Original assignee: Zpower, Llc
Priority date: 2017-09-06
Filing date: 2018-09-06
Publication date: 2019-03-14
Also published as: WO2019051026A3

Abstract

A method of charging a power storage device includes detecting a unique identifier of the power storage device, comparing the unique identifier to a list of one or more unique identifiers; and controlling a current to a power transmission coil of a charger based at least in part on the comparison of the unique identifier to the list of one or more unique identifiers.

Description

WIRELESS CHARGING SYSTEMS AND METHODS

CROSS REFERENCE TO RELATED APPLICATION

[0001] This PCT application claims the benefit of U.S. provisional application no.

62/554,710, filed on September 6, 2017. This document is hereby incorporated by reference in its entirety.

TECHNICAL FIELD

[0002] The present disclosure relates generally to systems and methods for wirelessly charging a power storage device.

BACKGROUND

[0003] This section provides background information related to the present disclosure and is not necessarily prior art.

[0004] Traditional wireless charging systems use inductive coupling, where a primary coil (e.g., a power transmit unit) is electromagnetically coupled to a secondary coil (e.g., a power receiver unit). Such systems require that the primary coil be in close proximity and alignment with the secondary coil, such that the secondary coil intercepts the flux of the magnetic field generated, and radiated in all directions, by the primary coil. The amount of energy captured by the secondary coil is proportional to the cross-sectional area of the secondary coil. For example, the energy captured by the secondary coil may be maximized when the dimensions of the secondary coil are equal to the dimensions of the primary coil, and the secondary coil is aligned (e.g., parallel) with, and separated by a small distance from, the primary coil. In this regard, the separation, alignment, and relative sizes of the primary and secondary coils determine a coupling factor, which, in turn, impacts the efficiency of the transfer of energy from the primary coil to the secondary coil. Known inductive charging systems typically have a coupling factor between 0.3 and 0.6.

[0005] In a resonant inductive coupling system, the primary and secondary coil resonate at identical frequencies. The primary coil generates an oscillating magnetic field that allows for more efficient power transfer between the primary and secondary coils, even when the separation, alignment, and relative sizes of the primary and secondary coils are less than what would otherwise be required in a traditional inductively coupled system. Moreover, a resonant inductive coupling system allows for energy transfer from a single primary coil to multiple secondary coils.

[0006] Many other wireless charging systems require that the device to be charged have available power in order to start the power transfer. [0007] While known wireless charging systems have proven acceptable for their intended purposes, a continuous need for improvement in the relevant art remains.

SUMMARY

[0008] This section provides a general summary of the disclosure, and is not a comprehensive disclosure of its full scope or all of its features.

[0009] One aspect of the disclosure provides a method of charging a power storage device. In some implementations, the method includes detecting a unique identifier of the power storage device. In some implementations, the method includes comparing the unique identifier to a list of one or more unique identifiers. In some implementations, the method further includes controlling a current to a power transmission coil of a charger based at least in part on the comparison of the unique identifier to the list of one or more unique identifiers.

[0010] Implementations of the disclosure may include one or more of the following optional features. In some embodiments, controlling the current to the power transmission coil includes charging the power storage device when the unique identifier matches a unique identifier of the list of unique identifiers.

[0011] In some embodiments, the method includes determining an amount of time between (i) detecting the unique identifier of the power storage device and (ii) a prior termination of communication between the power storage device and the power transmission coil. In some implementations, the method also includes comparing the amount of time to a threshold amount of time. In some implementations, the method includes controlling the current to the power transmission coil based at least in part on the comparison of the amount of time to the threshold amount of time. And, in some implementations, controlling the current to the power transmission coil includes charging the power storage device when the amount of time is greater than or equal to the threshold amount of time.

[0012] In some embodiments, the method includes determining a charge level of the power storage device corresponding to the prior termination of communication between the power storage device and the power transmission coil. In some implementations, the method also includes comparing the charge level to a threshold charge level. In some

implementations, the method includes controlling the current to the power transmission coil based at least in part on the comparison of the charge level to the threshold charge level. In some implementations, controlling the current to the power transmission coil includes charging the power storage device when the charge level is less than or equal to the threshold charge level. In some implementations, controlling the current to the power transmission coil includes terminating a flow of current to the power storage device when the charge level is greater than the threshold charge level.

[0013] In some embodiments, the method includes determining whether the power storage device is coupled to the charger, and indicating a charge level of the power storage device based on whether the power storage device is coupled to the charger.

[0014] In some embodiments, the method includes determining whether a first rate of communication between the charger and the power storage device is different than a second rate of communication between the charger and the power storage device. The second rate of communication may be subsequent to the first rate of communication.

[0015] Another aspect of the disclosure provides a system for charging a power storage device. The system may include a device sensor, a device comparison module, and a current control module. In some embodiments, the device sensor is operable to detect a unique identifier of the power storage device. In some embodiments, the device comparison module is configured to compare the unique identifier to a list of one or more unique identifiers. In some embodiments, the current control module is configured to control a current to a power transmission coil of a charger based at least in part on the comparison of the unique identifier to the list of one or more unique identifiers.

[0016] This aspect may include one or more of the following optional features. In some embodiments, the power transmission coil is configured to charge the power storage device when the unique identifier matches a unique identifier of the list of unique identifiers.

[0017] In some embodiments, the system includes a time module and a time comparison module. In some embodiments, the time module is configured to determine an amount of time between (i) detection of the unique identifier of the power storage device and (ii) a prior termination of communication between the power storage device and the power transmission coil. In some embodiments, the time comparison module is configured to compare the amount of time to a threshold amount of time. In some embodiments, the current control module is configured to control the current to the power transmission coil based at least in part on the comparison of the amount of time to the threshold amount of time.

[0018] In some embodiments, the power transmission coil is configured to charge the power storage device when the amount of time is greater than or equal to the threshold amount of time.

[0019] In some embodiments, the system includes a charger sensor and a charge comparison module. In some embodiments, the charge sensor is configured to determine a charge level of the power storage device corresponding to the prior termination of communication between the power storage device and the power transmission coil. In some embodiments, the charge comparison module is configured to compare the charge level to a threshold charge level. In some embodiments, the current control module is configured to control the current to the power transmission coil based at least in part on the comparison of the charge level to the threshold charge level. In some embodiments, the power transmission coil is configured to charge the power storage device when the charge level is less than or equal to the threshold charge level. In some embodiments, the power transmission coil is configured to terminate a flow of current to the power storage device when the charge level is greater than the threshold charge level.

[0020] In some embodiments, the power storage device is configured to determine whether a first rate of communication between the charger and the power storage device is different than a second rate of communication between the charger and the power storage device. The second rate of communication may be subsequent to the first rate of

communication.

[0021] Another aspect of the disclosure provides a method of charging a power storage device. In some implementations, the method includes detecting a chemical composition of a power storage device. In some implementations, the method also includes comparing the chemical composition to a list of one or more chemical compositions, and controlling a chemistry indicator based on the comparison of the chemical composition to the list of one or more chemical compositions.

[0022] In some implementations, controlling the chemistry indicator includes activating at least one of a visual indicator, an audible indicator, or a tactile indicator. Activating at least one of a visual indicator, an audible indicator, or a tactile indicator may include activating a first light source when the chemical composition corresponds to a first chemical composition, and activating a second light source when the chemical composition

corresponds to a second chemical composition.

[0023] Another aspect of the disclosure provides a method of preventing overcharging of a power storage device. In some implementations, the method includes detecting a device. For example, the method includes determining an identity of a device from a unique identifier. In some implementations, the method also includes determining an amount of time since the device was last charged. In some implementations, the method also includes resuming an interrupted charge. [0024] In some implementations, the method includes storing information on an internal storage of the device. For example, the method includes storing historical information (e.g., quantity of charging cycles, average charge time, average charge capacity, average discharge current, or quantity of errors) of the device on an internal memory of the device. In some implementations, the information is used to determine one or more characteristics of the power storage device, and may aid a manufacturer of the device in determining causes of returns.

[0025] In some implementations, the method includes charging a power storage device having no available, stored power. For example, the method includes starting a charging cycle on a rechargeable power source that has an available, stored power that is less than a shutdown threshold.

[0026] In some implementations, the method includes communicating data to or from the power storage device at a plurality of communication rates. The communication rate refers to how often communication is attempted between a power transmission board and a power receiving board. In some implementations, allowing for a plurality of communication rates permits the power storage device to require less power during times when communication is below a certain threshold required to operate the device. The power transmission board may determine and transmit the communication rate, and the power receiving board may receive and store the communication rate until power is lost or a new communication rate is determined.

[0027] In some implementations, the method includes detecting or otherwise determining a chemistry of the power storage device. For example, the method includes detecting when a non-rechargeable battery chemistry is coupled to a power transmission assembly (e.g., a charger). In some implementations, the method includes transmitting a warning signal until the chemistry detection step is complete.

[0028] Further areas of applicability will become apparent from the description provided herein. The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.

DESCRIPTION OF DRAWINGS

[0029] FIG. 1 is a perspective view of wireless charging system according to the principles of the present disclosure.

[0030] FIG. 2 is a functional block diagram of a wireless charging system according to the principles of the present disclosure. [0031] FIG. 3 is a flowchart illustrating an example wireless charging method according to the principles of the present disclosure.

[0032] FIG. 4 is a flowchart illustrating an example wireless charging method according to the principles of the present disclosure.

[0033] FIG. 5 is a flowchart illustrating an example wireless charging method according to the principles of the present disclosure.

[0034] Like reference symbols in the various drawings indicate like elements.

[0035] These figures are provided as examples and are not intended to limit the scope of the claimed invention.

DETAILED DESCRIPTION

[0036] Example configurations will now be described more fully with reference to the accompanying drawings. Example configurations are provided so that this disclosure will be thorough, and will fully convey the scope of the disclosure to those of ordinary skill in the art. Specific details are set forth such as examples of specific components, devices, and methods, to provide a thorough understanding of configurations of the present disclosure. It will be apparent to those of ordinary skill in the art that specific details need not be employed, that example configurations may be embodied in many different forms, and that the specific details and the example configurations should not be construed to limit the scope of the disclosure.

[0037] With reference to FIG. 1, a wireless charging system 10 in accordance with the principles of the present disclosure is illustrated. The wireless charging system 10 may include a charger 12 and a battery-powered device 14. While the device 14 is shown and described herein as being a hearing aid, it will be appreciated that the device 14 may include other battery-powered devices within the scope of the present disclosure. For example, in some implementations, the device 14 may include a battery-powered phone, camera, watch, or toy.

[0038] The charger 12 may include a housing 16 and one or more charger subassemblies 18. For example, as illustrated in FIG. 1, in some implementations, the charger 12 includes two charger subassemblies 18. As will be explained in more detail below, each charger subassembly 18 may be configured to receive the device 14 in order to transfer electrical power from the charger subassembly 18 to the device 14. In this regard, the charger 12 may be electrically coupled to an external power source (not shown) by a cord or other suitable wired or wireless transmission means. [0039] With reference to FIG. 2, the charger subassembly 18 may include a power transmitter assembly 26, one or more sensors 28, a processor 29, a memory 30, and one or more indicators 32. The power transmitter assembly 26 may include a conductor 36 (e.g., a power transmission coil). In some embodiments, the power transmitter assembly 26 has a printed circuit board and a power transmission coil. For instance, the power transmitter assembly 26 may include a printed circuit board assembly, a ferrite, a conductor 36, and a core. In some embodiments, the power transmitting coil is coupled to, and in communication with, the printed circuit board assembly. The core may include a non-conductive, ferrimagnetic material, such as a ceramic compound, for example. The core may define a substantially cylindrical construct having a diameter between one millimeter and five millimeters. For example, the core may define a diameter substantially equal to three millimeters. In some implementations, the core is integrally formed with the ferrite. In other implementations, the power transmitting coil is disposed above the core (e.g., the inner side of the power transmitting coil surrounds the core).

[0040] The processor 29 may be connected to, or in communication with, the memory 30 using various circuits. The processor 29 can process instructions for execution, including instructions stored in the memory 30. In other implementations, multiple processors and/or multiple buses may be used, as appropriate, along with multiple memories and types of memory.

[0041] The processor 29 may include a device comparison module 34-1, a current control module 34-2, a time comparison module 34-3, and a charge comparison module 34-4. As will be explained in more detail below, each module 34-1, 34-2, 34-3, 34-4 may

communicate with one or more of the sensors 28, the indicators 32, or the conductor 36 to control the transmission of power from the charger 12 to the device 14, or to control the transmission of information (e.g., visual, auditory, or tactile signals or other indicators) to a user of the charger 12.

[0042] The memory 30 stores information non-transitorily within the charger 12. For example, the memory 30 may contain instructions that, when executed by the processor 29, perform one or more methods, such as those described herein. The memory 30 may be a computer-readable medium, a volatile memory unit(s), or non-volatile memory unit(s). The non-transitory memory 30 may be physical devices used to store programs (e.g., sequences of instructions) or data (e.g., program state information) on a temporary or permanent basis for use by the processor 29. Examples of non-volatile memory include, but are not limited to, flash memory and read-only memory (ROM) / programmable read-only memory (PROM) / erasable programmable read-only memory (EPROM) / electronically erasable programmable read-only memory (EEPROM) (e.g., typically used for firmware, such as boot programs). Examples of volatile memory include, but are not limited to, random access memory (RAM), dynamic random access memory (DRAM), static random access memory (SRAM), phase change memory (PCM), as well as disks or tapes.

[0043] In some implementations, the memory 30 tracks or otherwise stores a list 40 of one or more unique identifiers UIDs and a list 42 of chemical compositions. As used herein, the term "chemical composition" refers to the composition of one or more species that undergoes chemical change (e.g., oxidation or reduction) during the charging or discharging of the power storage device (e.g., a cathode material, an anode material, or both). The list 40 of UIDs may include UIDs corresponding to devices (e.g., device 14) previously coupled to the charger 12. For example, the list 40 of UIDs may include a list of devices previously charged by the charger 12. The list 42 of chemical compositions includes a list of chemical compositions of commercially available power storages devices (e.g., batteries) of the device 14. For example, the list 42 of chemical compositions may include a list of chemical compositions of power storages devices compatible or incompatible with the charger 12. For example, in some implementations, the list 42 of chemical compositions includes a list of chemical compositions of power storages devices compatible with the charger 12. In some implementations, the list 42 of chemical compositions includes a list of chemical

compositions of power storages devices incompatible with the charger 12.

[0044] The sensors 28 may include a current sensor 28-1, a charge sensor 28-2, a charge cycle sensor 28-3, an error sensor 28-4, a chemistry sensor 28-5, a device sensor 28-6, and a time sensor 28-7. As will be explained in more detail below, during operation of the wireless charging system 10, the sensors 28 may detect and transmit various characteristics corresponding to the device 14. In particular, the sensors 28 may retrieve from the battery- powered device (e.g., a memory of the battery-powered device) values corresponding to characteristics of the battery-powered device. For example, the current sensor 28-1 may sense, or otherwise retrieve from the battery-powered device, the value of the electrical current being discharged from a power storage device (e.g., a battery) of the device 14, and transmit the sensed value of discharged electrical current to the processor 29 or memory 30. In particular, the current sensor 28-1 may transmit the sensed value of discharged electrical current of a battery of the device 14 to the memory 30 for storage. [0045] The charge sensor 28-2 may sense, or otherwise retrieve from the battery-powered device, the value of the charge of the power storage device (e.g., battery) of the device 14 and transmit the sensed value of the charge to the processor 29 or memory 30. For example, the charge sensor 28-2 may sense and transmit the amount of charge (e.g., fully charged, fully discharged, fifty percent charged, etc.) in a battery of the device 14.

[0046] The charge cycle sensor 28-3 may sense, or otherwise retrieve from the battery- powered device, the electrical coupling of the device 14 to the charger 12. For example, the charge cycle sensor 28-3 may sense the initiation of a charging cycle in which electrical current is transmitted from the conductor 36 to the device 14. In some implementations, the charge cycle sensor 28-3 assigns a value (e.g., first, second, third, etc.) to the charging cycle. In this regard, the charge cycle sensor 28-3 may determine the quantity of charging cycles initiated between the device 14 and the charger 12, and may transmit the quantity of charging cycles to the processor 29 or memory 30.

[0047] The error sensor 28-4 may sense, or otherwise retrieve from the battery-powered device, the quantity of coupling errors between the device 14 and the charger 12. For example, the error sensor 28-4 may sense the occurrence of an error during a charge cycle, or attempted charge cycle, between the device 14 and the charger 12. In particular, the error sensor 28-4 may sense an error in an attempted charging cycle of a power storage device (e.g., battery) of the device 14 (e.g., no battery present in the device 14, incorrect or incompatible chemistry of the battery of the device 14, overvoltage or overcurrent of the battery of the device 14, etc.) In some implementations, the error sensor 28-4 assigns a value (e.g., first, second, third, etc.) to the error. In this regard, the error sensor 28-4 may determine the quantity of errors during a charge cycle, or attempted charge cycle, between the device 14 and the charger 12, and may transmit the quantity of errors to the processor 29 or memory 30.

[0048] The chemistry sensor 28-5 may detect, or otherwise retrieve from the battery- powered device 14 (e.g., from a memory or storage space of the battery-powered device), a chemistry, or type, of the power storage device (e.g., battery) of the device 14. For example, the chemistry sensor 28-5 may detect whether a battery of the device 14 includes one of a nickel-cadmium, a nickel-metal-hydride, a zinc-air, a silver-zinc, a lead-acid, a lithium-ion, a lithium-ion polymer, or other battery chemistry. In this regard, the chemistry sensor 28-5 may detect a chemical composition of the battery of the device 14 and may transmit the chemical composition to the processor 29 or memory 30. As will be explained in more detail below, the charger 12 may determine whether the chemistry, or other characteristic, retrieved from the battery-powered device 14 matches, or otherwise corresponds to, an acceptable chemistry or characteristic stored in a memory of the charger 12. For example, the charger 12 may determine whether the chemistry of the battery-powered device 14 matches an acceptable chemistry stored in the list 42 of chemical compositions in the memory 30 of the charger 12.

[0049] The device sensor 28-6 may detect the presence of the device 14. For example, the device sensor 28-6 may sense a unique identification code UID of the device 14. In particular, the device sensor 28-6 may sense the unique identification code UID of a power storage device (e.g., battery) of the device 14 upon the coupling the device 14 to the charger 12. As will be explained in more detail below, detecting the unique identification code UID of the device 14 can prevent overcharging or undercharging the power storage device. For example, detecting the unique identification code UID can prevent overcharging or undercharging that might otherwise be caused by a loss of power during the process of charging the power storage device.

[0050] As will be explained in more detail below, in a first aspect, the device sensor 28-6 may detect the removal of the device 14 (e.g., a battery of the device 14) from the charger 12 and transmit a time, corresponding to the removal of the device 14, to the processor 29 (e.g., to the time comparison module 34-3). In a second aspect, the device sensor 28-6 may also detect the coupling of the device 14 to the charger 12 and transmit a time, corresponding to the coupling of the device 14, to the processor 29 (e.g., to the time comparison module 34-3).

[0051] The processor 29 may determine an amount of time between the removal of the device 14 from the charger 12 and the subsequent (e.g., next) coupling of the device 14 to the charger 12. Using the amount of time between the removal of the device 14 from the charger and the subsequent coupling of the device 14 to the charger, the wireless charging system 10 decides whether to resume a previous charging cycle of the power storage device of the device 14, or whether to start a new charging cycle of the power storage device of the device 14.

[0052] The indicators 32 may include one or more devices for producing a visual, auditory, or tactile indication. For example, the indicators 32 may include one or more sources of light (e.g., light-emitting diode(s)), sound (e.g., speaker(s)), or movement (e.g., motor(s)). As will be explained in more detail below, the indicators 32 may be in

communication with the processor 29 or the sensors 28 to produce one or more of the visual, auditory, or tactile indications upon sensing a chemistry corresponding to the device 14. For example, the processor 29 may activate the indicators 32 to produce one or more of the visual, auditory, or tactile indications upon receiving the chemistry of the device 14 from the chemistry sensor 28-5.

[0053] The device 14 may include a power receiver assembly 46, a power storage device such as a battery 48, and a memory 50. The power receiver assembly 46 may include a conductor 52 (e.g., a power receiver coil). The power receiver assembly 46 may include a power storage device (e.g., a battery 48), a substrate, and a conductor. The substrate may include a non-conductive, ferrimagnetic material, such as a ceramic compound, for example. In some implementations, the substrate defines a substantially rectangular shape having a length between five millimeters and ten millimeters, a width between two millimeters and four millimeters, and a thickness between 0.1 millimeters and 0.3 millimeters. In some implementations, the substrate defines a substantially rectangular shape having a length substantially equal to 6.7 millimeters, a width substantially equal to 3.1 millimeters, and a thickness substantially equal to 0.2 millimeters. It will be appreciated, however, that the substrate may define other shapes (e.g., oval, circle, stadium, etc.) within the scope of the present disclosure.

[0054] The conductor 52 may include a metallic wire having a length extending from a proximal end of the conductor 52 to a distal end of the conductor 52 opposite the proximal end, and defining a thickness or diameter between 0.10 millimeters and 0.20 millimeters along the length of the conductor 52. For example, the conductor 52 may include a copper wire having a thickness or diameter between 0.10 millimeters and 0.20 millimeters. In some implementations, the conductor 52 includes a copper wire having a thickness or diameter substantially equal to 0.15 millimeters. In an assembled configuration, the proximal end may be electrically coupled to a positive terminal (not shown) of the battery 48 and the distal end may be electrically coupled to a negative terminal (not shown) of the battery 48, such that the conductor 52 carries electrical current to the battery 48.

[0055] The device 14 may further include a unique identification code UID. For example, the power storage device (e.g., battery 48) of the device 14 may include the unique identification code UID, such that the unique identification code UID identifies the particular battery 48 of the device 14. As will be explained in more detail below, the unique identification code UID, including storage thereof, allows the wireless charging system 10 to prevent over charging and under charging of the power storage device. For example, storing the unique identification code UID may allow the wireless charging system 10 to prevent over charging and under charging of the battery 48 that might otherwise be caused by a loss of power during or after a charge cycle has been completed. As will be explained in more detail below, storing the various charge cycle data received from the sensors 28 can allow an entity (e.g., a manufacturer) to diagnose various conditions associated with the battery 48. For example, the value of the electrical current being discharged from the battery 48, and sensed by a current sensor, can be used by the charger 12 to determine an average discharge current for various discharge cycles of the battery 48. The average discharge current can be stored in a memory of the charger for future use by the manufacturer of the charging system 10 to better tailor charging for the system. Similarly, the number of errors detected and transmitted by an error sensor can be stored in the memory of the charger 12 for future use by the manufacturer of the charging system 10 to determine a cause of malfunctions in the charging system 10.

[0056] The memory 50 stores information non-transitorily within the device 14. For example, the memory 50 may contain instructions that, when executed by the processor 29, perform one or more methods, such as those described herein. The memory 50 may be a computer-readable medium, a volatile memory unit(s), or non-volatile memory unit(s). The non-transitory memory 50 may be physical devices used to store programs (e.g., sequences of instructions) or data (e.g., program state information) on a temporary or permanent basis for use by the processor 29. Examples of non-volatile memory include, but are not limited to, flash memory and read-only memory (ROM) / programmable read-only memory (PROM) / erasable programmable read-only memory (EPROM) / electronically erasable programmable read-only memory (EEPROM) (e.g., typically used for firmware, such as boot programs). Examples of volatile memory include, but are not limited to, random access memory (RAM), dynamic random access memory (DRAM), static random access memory (SRAM), phase change memory (PCM) as well as disks or tapes.

[0057] With reference to FIG. 3, a method 200 for charging a power storage device (e.g., battery 48) is shown. As explained in more detail below, the method 200 may prevent overcharging of the power storage device. In particular, the method 200 may prevent a power transmitter assembly (e.g., power transmitter assembly 26) from transferring power to a device (e.g., battery-powered device 14) after the power storage device of the device 14 has a predetermined charge level. The method 200 may include transmitting data between the power transmitter assembly and the device (e.g., battery-powered device 14, including the power storage device) at a plurality of different data transfer rates (e.g., low, normal, high). [0058] At step 202, the method 200 may include coupling a device (e.g., battery-powered device 14) to a charger (e.g., charger 12). For example, the method may include electrically coupling the power transmitter assembly 26 to the battery 48. In some implementations, the battery 48 may have a charge level below a predetermined threshold level. For example, the charge level of the battery 48 may be at or below a shutdown charge level at which the charge level of the battery 48 is below a minimum level required to operate the device 14. In some implementations, the method 200 may include initiating a recovery charge of the battery 48 if the charge level of the battery 48 is at or below the minimum charge level required to operate the device 14 start. Because electrical power (e.g., electrical power in the battery 48) may not be needed to electrically couple the power transmitter assembly 26 to the battery 48, the charging system 10 may detect if the device 14 has been connected to the charger 12, or whether the battery 48 has been removed from the device 14, by detecting a voltage of the battery 48 prior to initiating a charge (e.g., step 208) of the battery 48.

[0059] At step 204, the method 200 may include determining a unique identification code (e.g., UID) of the device (e.g., battery-powered device 14). For example, at step 204, the charger (e.g., charger 12) may detect the unique identification code UID of the battery 48. In particular, the device sensor 28-6 may detect the unique identification code UID of the battery 48 and transmit the unique identification code UID to the processor 29.

[0060] At step 206, the method 200 may include determining whether the device (e.g., battery-powered device 14) has previously been coupled to the charger (e.g., charger 12). For example, at step 206, the charger 12 may compare the unique identification code UID to the list 40 of unique identification codes corresponding to device(s) previously coupled to the charger. In this regard, the memory 30 may include the list of unique identification codes corresponding to device(s) previously coupled to the charger. In some implementations, communication between the charger and the battery powered device during steps 204 or 206 may occur at a "normal" data transfer rate. In this regard, during the "normal" data transfer rate, the processor 29 may attempt to communicate with the memory 30 between once every one hundred milliseconds and once every one second. In particular, the charger 12 may attempt to compare the unique identification code UIC of the device 14 to the list 40 of unique identification codes between once every one hundred milliseconds and once every one second.

[0061] If step 206 is false (e.g., if the unique identification code UID does not match a unique identification code in the list 40 of unique identification codes corresponding to device(s) previously coupled to the charger), the method 200 may proceed to step 208 where the charger may begin charging the power storage device (e.g., battery 48). In this regard, at step 208, the current control module 34-2 may control the transmission of power through the conductor 36 such that the conductor 36 may wirelessly transmit electrical power to the conductor 52. At step 208 (e.g., at an initiation of a charge cycle), a "high" data transfer rate may be utilized. In some implementations, during the "high" data transfer rate, the processor 29 may attempt to communicate with the memory 30 more than once every one hundred milliseconds. In some implementations, during the "high" data transfer rate, communication between the processor 29 and the memory 30 may be continuous.

[0062] If step 206 is true, the method 200 may proceed to step 210. At step 210, the method 200 may include determining an amount of time elapsed since the power storage device (e.g., the battery 48) was last charged by the charger (e.g., charger 12). For example, the method may include determining an amount of time elapsed since the power storage device was last disconnected from the charger. In particular, the method may include determining an amount of time elapsed since a last time the power storage device was electrically decoupled from the charger. In some implementations, the device sensor 28-6 detects the coupling of the device 14 to the charger 12 and transmits a time, corresponding to the coupling of the device 14 to the charger 12, to the processor 29 (e.g., to the time comparison module 34-3). The time comparison module 34-3 may determine the amount of time elapsed since a last time the power storage device was electrically decoupled from the charger.

[0063] At step 212, the method 200 may include determining whether the amount of time elapsed since the power storage device was last charged by the charger is less than a threshold amount of time. For example, at step 212, the method may determine whether the amount of time elapsed since the power storage device was last charged by the charger is less than a predetermined threshold amount of time. In some implementations, the time comparison module 34-3 determines whether the amount of time elapsed since the power storage device was last charged by the charger is less than a predetermined threshold amount of time. If step 212 is false, the method may proceed to step 208, where the charger may begin charging the power storage device (e.g., battery 48), and to step 214, where the charger may charge the power storage device until the power storage device is at a full (e.g., one hundred percent) or otherwise complete charge. For example, at step 214, the current control module 34-2 may control the transmission of power through the conductor 36 such that the conductor 36 wirelessly transmits electrical power through the conductor 52 for storage in the power storage device.

[0064] If step 212 is true, the method may proceed to step 216. At step 216, the method may include determining whether the power storage device (e.g., battery 48) is at a threshold charge level. For example, at step 212, the charge sensor 28-2 may retrieve the value of the charge level (e.g., the state of charge) of the power storage device (e.g., battery 48) of the device 14. In some implementations, the charge sensor 28-2 may retrieve the value of the charge (e.g., the state of charge) of the power storage device from the memory 30. The threshold charge level (e.g., the threshold state of charge) may include a predetermined charge level. For example, the threshold charge level may be between eighty percent and one hundred percent. In this regard, at step 216, the method may include determining whether the power storage device is at a full (e.g., one hundred percent) charge level. In some implementations, the charge comparison module 34-4 may compare the value of the charge retrieved by the charge sensor 28-2 to the threshold charge level to determine whether the battery 48 is at a full (e.g., one hundred percent) charge level. If step 216 is true, the method may proceed to step 220.

[0065] If step 216 is false, the method may proceed to step 218, where the method may include loading various parameters corresponding to previous charge cycles of the power storage device (e.g., battery 48) into the memory 30. For example, at step 218, previous values of the charge level of the power storage device (e.g., battery 48), stored in the memory 50, may be transmitted to the processor 29 by the sensors 28. In some implementations, the value of the electrical current charged to, or discharged from, the battery 48, and stored in the memory 50, is retrieved by the current sensor 28-1 and transmitted to the processor 29 by the current sensor 28-1. In some implementations, the amount of charge (e.g., fully charged, fully discharged, fifty percent charged, etc.) of the power storage device is retrieved by the charge sensor 28-2 in the battery 48 and transmitted to the processor 29 by the charge sensor 28-2. In some implementations, the value (e.g., first, second, third, etc.) of the charging cycle or the quantity of charging cycles initiated between the device 14 and the charger 12, stored in the memory 50, is retrieved by the charge cycle sensor 28-3 and transmitted to the processor 29 by the charge cycle sensor 28-3. Similarly, the number of errors, stored in the memory 50, may be detected and transmitted by the error sensor 28-4 and transmitted to the processor 29. The sensors 28 or processor 29 may transmit the various parameters (e.g., voltage of the power storage device, charge or discharge current, value of the charging cycle, etc.) through the processor 29 or to the memory 50 using a "normal" data transfer rate. In some implementations, during the "normal" data transfer rate, the processor 29 attempts to communicate with the memory 50 between once every one hundred milliseconds and once every one second.

[0066] In some implementations, the method 200 proceeds from step 218 to step 214 and to step 220. At step 220, the method may include indicating via an audible or visual indicator the completion of the charging step (e.g., step 214). For example, at step 220, the method may include switching a light, speaker, or other suitable indicator 32-1 into an "ON" position to indicate the completion of step 214. For example, the processor 29 may activate the indicator 32 into the "ON" position. A "low" data transfer rate may be utilized when the power storage device is fully charged or during low power applications to reduce the power consumption of the device (e.g., device 14) while the device is in communication with the charger (e.g., charger 12). For example, the "low" data transfer rate may be utilized during step 220. In some implementations, during the "low" data transfer rate, the processor 29 attempts to communicate with the memory 50 between once every one second and once every ten seconds.

[0067] At step 222, the method may include determining whether the device (e.g., battery-powered device 14) has been removed from the charger (e.g., charger 12). For example, at step 222, the method may include determining whether the power storage device (e.g., battery 48) is in communication with, or otherwise coupled to, the charger 12. In particular, the device sensor 28-6 may determine whether the power storage device is coupled to the charger. If step 222 is true, the method may return to step 202. If step 222 is false, the method may return to step 220.

[0068] With reference to FIG. 4, a method 300 for preventing the charging of a power storage device (e.g., battery 48) that is not rechargeable, or that a charger (e.g., charger 12) is not able to charge, is shown. In particular, the method 300 may prevent a power transmitter assembly (e.g., power transmitter assembly 26) from transferring power to a device (e.g., battery-powered device 14) if the power storage device is not rechargeable or if a chemistry of the power storage device is incompatible with, or otherwise does not correspond to, the charger (e.g., charger 12).

[0069] At step 302, the method 300 may include coupling a device (e.g., battery-powered device 14) to a charger (e.g., charger 12). For example, the method may include electrically coupling the power transmitter assembly 26 to the battery 48. [0070] At step 304, the method 300 may include detecting a characteristic of the power storage device (e.g., battery 48) of the device 14. For example, at step 304, the chemistry sensor 28-5 may detect a chemistry or chemical composition of the battery 48. In particular, at step 304, the chemistry sensor 28-5 may detect whether the battery 48 includes one of a nickel-cadmium, a nickel-metal-hydride, a lead-acid, a zinc-air, a silver-zinc, a lithium-ion, a lithium-ion polymer, or other battery chemistry. In this regard, the chemistry sensor 28-5 may detect a chemical composition of the battery 48 and may transmit the chemical composition to the processor 29 (e.g., a printed circuit board). During step 304, the processor 29 may activate one or more of the indicators 32 to produce the visual, auditory, or tactile indication that the chemistry sensor 28-5 is detecting a chemistry or chemical composition of the battery 48. In some implementations, the indicator 32 may include a colored (e.g., yellow) first light-emitting diode 32-1 (FIG. 2) that is activated at step 308.

[0071] At step 306, the method 300 may include determining whether the chemical composition of the power storage device (e.g., the battery 48) is rechargeable or otherwise compatible with the charger (e.g., charger 12). For example, at step 306, the charger may compare the chemical composition detected at step 304 to the list 42 of chemical

compositions compatible with the charger 12. If step 306 is true (e.g., if the chemical composition of the battery 48 matches a chemical composition in the list 42 of compatible chemical compositions), the method may proceed to step 308.

[0072] At step 308, the method may include indicating that the chemical composition of the power storage device (e.g., the battery 48) matches, or otherwise corresponds to, a chemical composition in the list 42 of compatible chemical compositions. For example, at step 308, the indicators 32 may produce one or more of a visual, auditory, or tactile indication that the chemical composition of the battery 48 is compatible with the charger 12. In this regard, the processor 29 may activate one or more of the indicators 32 to produce the visual, auditory, or tactile indication that the battery 48 is compatible with the charger 12. In some implementations, the indicator 32 may include a colored (e.g., green) second light-emitting diode 32-2 (FIG. 2) that is activated at step 308. At step 310, the method may include charging the battery 48. For example, at step 310, the processor 29 may instruct the power transmitter assembly 26 to initiate charging of the battery 48. In particular, the processor 29 may activate a switch to provide power to the conductor 36.

[0073] If step 306 is false (e.g., if the chemical composition of the battery 48 does not match a chemical composition in the list 42 of compatible chemical compositions), the method may proceed to step 312. At step 312, the method may include indicating that the chemical composition of the power storage device (e.g., the battery 48) does not match, or otherwise does not correspond to, a chemical composition in the list 42 of compatible chemical compositions. For example, at step 312, the indicators 32 may produce one or more of a visual, auditory, or tactile indication that the chemical composition of the battery 48 is incompatible with the charger 12. In this regard, the processor 29 may activate one or more of the indicators 32 to produce the visual, auditory, or tactile indication that the battery 48 is incompatible with the charger 12. In some implementations, the indicator 32 may include a colored (e.g., red) third light-emitting diode 32-3 that is activated at step 312. At step 314, the method may include terminating communication between the battery 48 and the charger 12. For example, at step 314, the processor 29 may activate a switch to terminate power to the conductor 36.

[0074] With reference to FIG. 5, a method 400 for determining a rate of communication in a wireless charging system (e.g., wireless charging system 10) is illustrated. In particular, the method 400 may instruct one of a charger (e.g., charger 12) or a battery-powered device (e.g., battery-powered device 14) to communicate with the other of the charger or the battery- powered device at a preferred rate of communication. As used herein, rate of communication may refer to quantity of communication attempts from the charger to the battery-powered device (or vice versa) during a period of time (e.g., second, minute, etc.). In this regard, the method 400 may instruct the battery-powered device to attempt communicating with the charger a predetermined rate of communication.

[0075] At step 402, the method may include selecting or otherwise determining a rate of communication, and transmitting the rate of communication to the battery-powered device. For example, at step 402, the charger (e.g., charger 12) may determine a preferred rate of communication between the charger and the battery-powered device, and transmit the rate of communication to the battery-powered device. In some implementations, at step 402, the charger may determine a preferred rate of communication based on a state of the charging system (e.g., wireless charging system 10). In particular, if the charging system is in a state of runtime data transfer, the charger may select a normal rate of communication. For example, if the battery-powered device is transmitting data (e.g., voltage, charge current, charge status) to the charger, the charger may select a normal rate of communication at step 402. In this regard, the charger may select a rate of communication of between one attempted communication every one hundred milliseconds and one attempted communication every one second. If the charging system is in a startup state or a programming state, the charger may select a high rate of communication at step 402. For example, if the battery-powered device is initiating a charge cycle or programming new firmware (e.g., programming new

instructions to the memory 50), the charger may select a high rate of communication at step 402. In this regard, the charger may select a rate of communication of at least one

communication every ten milliseconds. If the charging system is in a charge complete state, the charger may select a low rate of communication at step 402. For example, if the power storage device (e.g., battery 48) of the battery-powered device is at a full or one hundred percent charge, the charger may select a low rate of communication at step 402. In this regard, the charger may select a rate of communication less than or equal to one

communication every five seconds.

[0076] At step 404, the method may include determining whether the rate of

communication determined or transmitted at step 402 is a new rate of communication. For example, the battery-powered device (e.g., battery-powered device 14) may determine at step 404 whether the rate of communication transmitted at step 402 is different than a previous rate of communication. In particular, the method may determine at step 404 whether the rate of communication transmitted at step 402 is different than the immediately preceding, or current, rate of communication.

[0077] If step 404 is true, the method may proceed to step 406. At step 406, the method may include setting a value for a timer (e.g., time comparison module 34-3) corresponding to the rate of communication determined at step 402. For example, if step 404 is true, the battery-powered device may set the timer to a value of between one hundred milliseconds and one second if step 402 transmits a normal rate of communication. Similarly, if step 404 is true, the method may set the timer to a value of less than or equal to ten milliseconds if step 402 transmits a high rate of communication, or greater than or equal to five seconds if step 402 transmits a low rate of communication.

[0078] At step 408, the method may include determining whether an elapsed amount of time is greater than or equal to the value set for the timer. For example, the time comparison module may determine whether an amount of time elapsed since an immediately preceding communication attempt between the charger and the battery-powered device is greater than or equal to the value set for the timer. In this regard, in some implementations, the method may determine whether the amount of time elapsed since an immediately preceding

communication attempt between the charger and the battery-powered device is greater than or equal to the value for the timer set at step 406. If step 408 is false, the method may return to step 408. In particular, the method may repeat step 408.

[0079] If step 408 is true, the method may proceed to step 410 which may include attempting to communicate between the charger and the battery-powered device. In this regard, at step 410, the charger may attempt to communicate with the battery-powered device at one of the high, normal, or low rates of communication. The method may then return to step 404, where the battery-powered device may determine whether a subsequent rate of communication transmitted by the charger at step 402 is different than the current, or immediately preceding, rate of communication. The method may continue by continuously repeating one or more of steps 402-410 while the battery-powered device is coupled to the charger.

[0080] Various implementations of the systems and techniques described herein can be realized in digital electronic and/or optical circuitry, integrated circuitry, specially designed ASICs (application specific integrated circuits), computer hardware, firmware, software, and/or combinations thereof. These various implementations can include implementation in one or more computer programs that are executable and/or interpretable on a programmable system including at least one programmable processor, which may be special or general purpose, coupled to receive data and instructions from, and to transmit data and instructions to, a storage system, at least one input device, and at least one output device.

[0081] These computer programs (also known as programs, software, software applications or code) include machine instructions for a programmable processor, and can be implemented in a high-level procedural and/or object-oriented programming language, and/or in assembly/machine language. As used herein, the terms "machine -readable medium" and "computer-readable medium" refer to any computer program product, non-transitory computer readable medium, apparatus and/or device (e.g., magnetic discs, optical disks, memory, Programmable Logic Devices (PLDs)) used to provide machine instructions and/or data to a programmable processor, including a machine-readable medium that receives machine instructions as a machine-readable signal. The term "machine-readable signal" refers to any signal used to provide machine instructions and/or data to a programmable processor.

[0082] The processes and logic flows described in this specification can be performed by one or more programmable processors executing one or more computer programs to perform functions by operating on input data and generating output. The processes and logic flows can also be performed by special purpose logic circuitry, e.g., an FPGA (field programmable gate array) or an ASIC (application specific integrated circuit). Processors suitable for the execution of a computer program include, by way of example, both general and special purpose microprocessors, and any one or more processors of any kind of digital computer. Generally, a processor will receive instructions and data from a read only memory or a random access memory or both. The essential elements of a computer are a processor for performing instructions and one or more memory devices for storing instructions and data. Generally, a computer will also include, or be operatively coupled to receive data from or transfer data to, or both, one or more mass storage devices for storing data, e.g., magnetic, magneto optical disks, or optical disks. However, a computer need not have such devices. Computer readable media suitable for storing computer program instructions and data include all forms of non-volatile memory, media and memory devices, including by way of example semiconductor memory devices, e.g., EPROM, EEPROM, and flash memory devices;

magnetic disks, e.g., internal hard disks or removable disks; magneto optical disks; and CD ROM and DVD-ROM disks. The processor and the memory can be supplemented by, or incorporated in, special purpose logic circuitry.

[0083] To provide for interaction with a user, one or more aspects of the disclosure can be implemented on a computer having a display device, e.g., a CRT (cathode ray tube), LCD (liquid crystal display) monitor, or touch screen for displaying information to the user and optionally a keyboard and a pointing device, e.g., a mouse or a trackball, by which the user can provide input to the computer. Other kinds of devices can be used to provide interaction with a user as well; for example, feedback provided to the user can be any form of sensory feedback, e.g., visual feedback, auditory feedback, or tactile feedback; and input from the user can be received in any form, including acoustic, speech, or tactile input. In addition, a computer can interact with a user by sending documents to and receiving documents from a device that is used by the user; for example, by sending web pages to a web browser on a user's client device in response to requests received from the web browser.

[0084] A number of implementations have been described. Nevertheless, it will be understood that various modifications may be made without departing from the spirit and scope of the disclosure. Accordingly, other implementations are within the scope of the following claims.

Claims

CLAIMS WHAT IS CLAIMED IS:

1. A method of charging a power storage device, the method comprising:

detecting a unique identifier of the power storage device;

comparing the unique identifier to a list of one or more unique identifiers; and controlling a current to a power transmission coil of a charger based at least in part on the comparison of the unique identifier to the list of one or more unique identifiers.

2. The method of claim 1, wherein controlling the current to the power transmission coil includes charging the power storage device when the unique identifier matches a unique identifier of the list of unique identifiers.

3. The method of either of claims 1 or 2, further comprising:

determining an amount of time between (i) detecting the unique identifier of the power storage device and (ii) a prior termination of communication between the power storage device and the power transmission coil;

comparing the amount of time to a threshold amount of time; and

controlling the current to the power transmission coil based at least in part on the comparison of the amount of time to the threshold amount of time.

4. The method of claim 3, wherein controlling the current to the power transmission coil includes charging the power storage device when the amount of time is greater than or equal to the threshold amount of time.

5. The method of any one of claims 1-4, further comprising:

determining a charge level of the power storage device corresponding to the prior termination of communication between the power storage device and the power transmission coil;

comparing the charge level to a threshold charge level; and

controlling the current to the power transmission coil based at least in part on the comparison of the charge level to the threshold charge level.

6. The method of claim 5, wherein controlling the current to the power transmission coil includes charging the power storage device when the charge level is less than or equal to the threshold charge level.

7. The method of claim 5, wherein controlling the current to the power transmission coil includes terminating a flow of current to the power storage device when the charge level is greater than the threshold charge level.

8. The method of any one of claims 1-7, further comprising:

determining whether the power storage device is coupled to the charger; and indicating a charge level of the power storage device based on whether the power storage device is coupled to the charger.

9. The method of any one of claims 1-8, further comprising determining whether a first rate of communication between the charger and the power storage device is different than a second rate of communication between the charger and the power storage device, wherein the second rate of communication is subsequent to the first rate of communication.

10. A system for charging a power storage device, the system comprising:

a device sensor operable to detect a unique identifier of the power storage device; a device comparison module configured to compare the unique identifier to a list of one or more unique identifiers; and

a current control module configured to control a current to a power transmission coil of a charger based at least in part on the comparison of the unique identifier to the list of one or more unique identifiers.

11. The system of claim 10, wherein the power transmission coil is configured to charge the power storage device when the unique identifier matches a unique identifier of the list of unique identifiers.

12. The system of either of claims 10 or 11, further comprising: a time module configured to determine an amount of time between (i) detection of the unique identifier of the power storage device and (ii) a prior termination of communication between the power storage device and the power transmission coil; and

a time comparison module configured to compare the amount of time to a threshold amount of time,

wherein the current control module is configured to control the current to the power transmission coil based at least in part on the comparison of the amount of time to the threshold amount of time.

13. The system of claim 12, wherein the power transmission coil is configured to charge the power storage device when the amount of time is greater than or equal to the threshold amount of time.

14. The system of any one of claims 10-13, further comprising:

a charge sensor configured to determine a charge level of the power storage device corresponding to the prior termination of communication between the power storage device and the power transmission coil; and

a charge comparison module configured to compare the charge level to a threshold charge level,

wherein the current control module is configured to control the current to the power transmission coil based at least in part on the comparison of the charge level to the threshold charge level.

15. The system of claim 14, wherein the power transmission coil is configured to charge the power storage device when the charge level is less than or equal to the threshold charge level.

16. The system of claim 14, wherein the power transmission coil is configured to terminate a flow of current to the power storage device when the charge level is greater than the threshold charge level.

17. The system of any one of claims 10-16, wherein the power storage device is configured to determine whether a first rate of communication between the charger and the power storage device is different than a second rate of communication between the charger and the power storage device, wherein the second rate of communication is subsequent to the first rate of communication.

18. A method of charging a power storage device, the method comprising:

detecting a chemical composition of a power storage device;

comparing the chemical composition to a list of one or more chemical compositions; and

controlling a chemistry indicator based on the comparison of the chemical composition to the list of one or more chemical compositions.

19. The method of claim 18, wherein controlling the chemistry indicator includes activating at least one of a visual indicator, an audible indicator, or a tactile indicator.

20. The method of claim either of claims 18 or 19, wherein activating at least one of a visual indicator, an audible indicator, or a tactile indicator includes activating a first light source when the chemical composition corresponds to a first chemical composition, and activating a second light source when the chemical composition corresponds to a second chemical composition.