Patent Publication Number: US-11043844-B2

Title: Stackable battery pack with wireless charging

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     The present application is a continuation of U.S. patent application Ser. No. 16/400,489, filed May 1, 2019, which claims priority to U.S. Provisional Patent Application No. 62/718,521, filed Aug. 14, 2018, all of which are hereby incorporated by reference in their entireties. 
    
    
     FIELD 
     This application relates to rechargeable battery backs for charging, recharging, and/or powering electronic devices. 
     BACKGROUND 
     Many types of portable electronic devices are available including smart phones (or smartphones), personal digital assistants (PDAs), tablet computers, laptop computers, phablets (phone/tablets), gaming devices, global positioning satellite (GPS) receivers, and multimedia players (such as mp3 players, video players, and the like). These devices typically operate using one or more batteries. In many cases, these batteries are rechargeable. These types of devices are often used in mobile or remote fashions and battery life can often be an issue. Increases in processing power and screen size often cause battery power to be consumed at an even higher rate than earlier devices. Consequently, battery life and access to a power source for recharging the batteries often become issues when using these types of devices. It is expected that the demands placed on battery-operated devices will continue to grow. 
     Manufacturers have developed portable power sources (e.g., portable batteries and battery packs) that can be transported and provide convenient access to power for powering or recharging various types of electronic devices. However, conventional portable batteries and power sources can sometimes be inconvenient for a variety of reasons. Conventional battery packs which use cables may be inconvenient in some circumstances for reasons such as: a need to remember carry the cable along with the battery pack, the inconvenience of storing the cable and keeping it untangled, and/or the need to attach the cable to both the battery pack and the device in order to charge the device. In addition, a user who carries his or her own battery pack with them must remember to recharge the battery pack. 
     SUMMARY 
     A rechargeable battery pack and battery pack system with improved features are disclosed herein. In one implementation, a rechargeable battery pack system includes a charging base and two or more rechargeable battery packs. The rechargeable battery packs are for use with electronic devices having wireless charging interfaces. The charging base may include an electrical connector configured for receiving electrical power from an external power source, electrical contacts, and an inductive coil configured for wirelessly transmitting at least a portion of the received electrical power to one of the electronic devices through the wireless charging interface of the electronic device when the one electronic device is in proximity to the charging base. Each of the battery packs may include a rechargeable battery, electrical circuitry, electrical contacts, and electrical pins. The battery packs may be stackable on the charging base such that a first one of the battery packs stacked directly on the charging base receives electrical power from the charging base for one or more of charging the rechargeable battery of the first battery pack and transferring electrical power to a second one of the two battery packs when the second battery pack is stacked directly on the first battery pack. Each battery pack may also include an inductive coil configured for wirelessly transmitting electrical power to an electronic device when the electronic device is in proximity to the battery pack. 
     In another variation, a rechargeable battery pack system includes a charging base and a plurality of rechargeable battery packs. The charging base includes an electrical connector configured for receiving electrical power into the charging base from an external power source and a set of electrical contacts. The plurality of rechargeable battery packs each include a rechargeable battery, electrical circuitry, and an inductive coil configured for wirelessly transmitting electrical power from the rechargeable battery to a wireless charging interface of an electronic devices when the electronic device is in proximity to the inductive coil. The rechargeable battery packs each further include a first set of electrical contacts configured to electrically contact a first device for receiving electrical power from the first device when the rechargeable battery pack is stacked on the first device. The first device may be the charging base or another of the plurality of rechargeable battery packs. The rechargeable battery packs further include a second set of electrical contacts configured to electrically contact the first set of electrical contacts of another of the plurality of rechargeable battery packs for providing electrical power to the other rechargeable battery pack when the other rechargeable battery pack is stacked on the rechargeable battery pack. The second set of electrical contacts is activated for providing the electrical power to the other rechargeable battery pack only after receiving an identity code from the other rechargeable battery pack and verifying the identity code. 
     In yet another example, a rechargeable battery pack system includes a first charging base configured for receiving electrical power from an external power source and a second charging base configured for receiving electrical power from an external power source. The system further includes a first portable battery pack and a second portable battery pack. The first portable battery pack has alignment features configured to mechanically interface to both the first charging base and the second charging base. The first portable battery pack is configured to be rechargeable by each of the first charging base and the second charging base, after transmitting a verifiable identification code to the respective charging base. The second portable battery pack also has alignment features configured to mechanically interface to both the first charging base and the second charging base. The second portable battery pack is configured to be rechargeable by the second charging base after transmitting a verifiable identification code to the second charging base, but is not rechargeable by the first charging base. 
     In yet another example, a rechargeable battery pack for use with a charging base a rechargeable battery includes electrical circuitry and an inductive coil configured for wirelessly transmitting electrical power from the rechargeable battery to a wireless charging interface of an electronic device when the electronic device is in proximity to the inductive coil. The rechargeable battery pack also includes a first set of electrical contacts configured to electrically contact a first device for receiving electrical power from the first device when the rechargeable battery pack is stacked on the first device. The first device may be, alternately, one of the charging base and another instance of the rechargeable battery pack. The rechargeable battery pack further includes a second set of electrical contacts configured to electrically contact the first set of electrical contacts of another instance of the rechargeable battery pack for providing electrical power to the other rechargeable battery pack when the other rechargeable battery pack is stacked on the rechargeable battery pack. The second set of electrical contacts is activated for providing the electrical power to the other rechargeable battery pack after receiving an identification code from the other rechargeable battery pack and verifying the identification code is associated with a compatible device. The second set of electrical contacts may be positioned on an opposite side of the rechargeable battery pack from the position of the first set of electrical contacts. 
     Beneficially, the rechargeable battery packs described herein can be used to wirelessly recharge an electronic device, such as a smartphone. Eliminating the need to use a cable in the charging and/or discharging of the battery pack makes the processes easier for the user and may eliminate the need to carry a cable along with the battery pack. In addition, eliminating electrical connectors on the battery pack also makes the battery pack more resilient to damage and can reduce chances that it could be damaged by water, snow, rain, dust, dirt, or a contaminant or damaging element of another type. Reducing the number of connectors or cables can also make the rechargeable battery pack more compact, more aesthetically pleasing, and/or expand packaging options for the battery pack. 
     While there are benefits to eliminating cables as discussed above, cables may still be useful in some circumstances. In some configurations, a battery pack may include both the wireless charging/discharging capabilities discussed herein as well as cables and/or connectors for use with cables. 
     Various improvements are disclosed herein in the form of apparatuses, devices, components, systems, and methods. In some situations, improvements may include features implemented as non-transitory machine-executable computer instructions that may be executed by one or more computer processors to perform one or more of the improvements disclosed herein or to perform a portion of one or more of the improvements disclosed herein. 
     While many of the examples herein are discussed with respect to a “battery” pack, it should be understood that the techniques, improvements, apparatuses, systems, and methods disclosed herein are equally applicable to power packs or portable energy storage devices utilizing other methods of power storage including: fuel cells, lithium titanate cells, capacitive energy storage devices, super capacitors, kinetic energy storage devices, thermal energy storage devices, and/or combinations thereof. The claims are not to be limited to any particular type of power storage device. 
    
    
     
       BRIEF DESCRIPTIONS OF DRAWINGS 
       In the drawings, 
         FIG. 1  illustrates a rechargeable battery pack; 
         FIG. 2  illustrates a bottom perspective view of the rechargeable battery pack of  FIG. 1 ; 
         FIG. 3  illustrates the rechargeable battery pack of  FIG. 1  charging an electronic device; 
         FIG. 4  illustrates a charging base; 
         FIG. 5  illustrates the charging base of  FIG. 5  with a stack of rechargeable battery packs; 
         FIG. 6  illustrates the charging base of  FIG. 4  charging an electronic device; 
         FIG. 7  illustrates a stand with an electronic device and the rechargeable battery pack of  FIG. 1 ; and 
         FIG. 8  illustrates a close-up view of a portion of the stand of  FIG. 7 . 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  illustrates a battery pack  100 . Any of the battery packs disclosed herein may also be referred to as a wireless battery packs, rechargeable battery packs, and/or portable battery packs, but for simplicity are often simply referred to as “battery packs.” Battery pack  100  includes a housing  110  that supports or contains a variety of components, such as display elements  140 , electrical port  160 , button  120 , and top alignment guide  130 . Housing  110  also includes a top surface  112 . Housing  110  may comprise two or more portions or members that are attached together to form housing  110 . 
     Battery pack  100  may also contain a number of internal components that are not visible in  FIG. 1  such as a printed circuit board, a rechargeable battery, electrical components, discrete components, electrical circuitry, analog components, digital components, a microprocessor, a microcontroller, memory, a voltage controller, a voltage booster, a current limiter, a battery charge controller, a battery monitor, electromechanical connectors, an electrical coil, an inductive electrical coil, a modulator, a demodulator, an rf transmitter, an rf receiver, an antenna, a filter, a mixer, and/or an amplifier. 
     Display element(s)  140  comprise one or more devices for visually conveying status or information to a user of battery pack  100 . Display element(s)  140  may include one or more of: a light emitting diode (LED), an organic light emitting diode (OLED), a liquid crystal display (LCD), electronic paper, electrophoretic ink, and/or another type of device for visually conveying information to a user, including combinations thereof. Display element(s)  140  may be made up of a group of discrete display elements, such as a group of LEDs. Display element(s)  140  may also be made up of a single display device, such as an LCD, containing a plurality of display elements, segments, or areas. Display elements(s)  140  may be illuminated in a variety of combinations, sequences, colors, patterns, and/or intensities to convey various information about an operating mode, status, and/or condition of battery pack  100 . They may also convey information about a battery of battery pack  100  and/or another device to which battery pack  100  is interfaced. Battery pack  100  may also convey information using an audio device for generating an audible signal which may include a speaker, a buzzer, a beeper, a piezoelectric device, and/or a combination thereof. 
     Electrical contacts  154  of battery pack  100  are used for conducting electrical power and/or data signals. Electrical contacts  154  may be any type of conductive electrical contacts, probes, pins, and/or pads for making electrical contact to another device. Electrical contacts  154  may be spring loaded, floating, movable, and/or have play for more easily and reliably making contact to other devices. In one specific example, pogo pins may be used. Electrical contacts  154  are at or near a plane of top surface  112  such that they may contact a device which is place or stacked on top of battery pack  100 . While five electrical contacts are illustrated, other quantities are possible including two, three, four, six, seven, or more. The electrical contacts may be separate elements or may comprise single assembly. 
     In some configurations, an industry standard electromechanical connector may be used in place of or in addition to electrical contacts  154 . In some examples, electrical contacts  154  and/or electrical contacts  152  (discuss in detail below with respect to  FIG. 2 ) may be recessed from the surface or be positioned in a recessed area to reduce chances of unintended contact. In other examples, electrical contacts  154  and/or electrical contacts  152  may have one or more raised or protruding housing portions around them to reduce chances of unintended contact. 
     Button  120  includes one or more devices through which a user may provide an input to battery pack  100 . Button  120  may include a switch, a group of switches, a button, a group of buttons, an optical detector, a touch sensitive device, a proximity sensor, a capacitance sensor, or a combination thereof. As described later in further detail, button  120  may be used to switch battery pack  100  on, to switch battery pack  100  off, to change an operational mode of battery pack  100 , to select a feature of battery pack  100 , to deselect a feature of battery pack  100 , or a combination thereof. 
     The one or more rechargeable batteries included in battery pack  100  may be configured for supplying power to one or more other devices, as well as to internal components of battery pack  100 . The rechargeable battery(s) may comprise one or more of a variety of electrical power storage technologies including lithium ion (Li-ion), lithium ion polymer (Li-ion polymer), lead-acid, nickel cadmium (NiCd), nickel metal hydride (NiMH), nickel-zinc, alkaline, fuel cells, lithium titanate cells, capacitive energy storage devices, super capacitors, and/or any other type of device for storing energy. While the term “battery” is primarily used herein for purposes of explanation, the apparatuses, methods, systems, and techniques described herein are applicable for use with any power or energy storage technology. The apparatuses, methods, and techniques described herein are not to be limited to any particular type of battery or energy storage technology. 
     The electrical circuitry of battery pack  100  may include one or more devices for controlling various elements of battery pack  100  and/or for performing processing functions. The electrical circuitry may include any type of microcontroller, microprocessor, microcomputer, programmable logic device, reconfigurable circuit, digital signal processor, or application specific circuit that is configured to communicate with other elements of battery pack  100  and/or to perform power management functions associated with battery pack  100 . In some configurations, these power management functions may be described as ‘intelligent’ power management functions. 
     In some configurations, the electrical circuitry may also include communication circuitry to communicate with one or more electronic devices which battery pack  100  is interfaced with, either through a wired or wireless connection. The communication circuitry may also communicate with other devices, such as a charging base, and may make use of software, firmware, and/or another type of non-transitory computer executable program instructions stored in the device. 
     Wireless communication circuitry of battery pack  100  may include any device or combination of devices for enabling wireless communication between battery pack  100  and one or more electronic devices. The wireless communication, if any, may be compatible with one or more wireless communication standards, or industry standards, such as WIFI, BLUETOOTH, BLUETOOTH LOW ENERGY, NFC, ZIGBEE, and/or any other wireless communication standard, such as a cellular wireless communication standard. Wireless communication may also be conducted using optical or infrared communication methods. The wireless communication may include simplex, half-duplex, and/or full duplex communication. 
     Battery pack  100  may also include an electrical port  160  for receiving electrical power through a cable and/or transmitting electrical power through a cable. Electrical port  160  includes any electromechanical interface or connector for receiving or transmitting electrical power and/or data signals. Electrical port  160  may include any type of jack, plug, or electromechanical connector. For example, electrical port  160  may include a USB connector, a mini USB connector, a micro USB connector, a USB-C connector, an APPLE LIGHTNING connector, and/or any other type of electromechanical connector configured to conduct power and/or facilitate data communications. While one electrical port  160  is illustrated, battery pack  100  may include two or more electrical ports. Electrical port  160  may facilitate receiving electrical power from an external power source for recharging the battery. In some cases, an external electrical transformer or converter may also be used. Electrical port  160  may also facilitate sending electrical power from battery pack  100  to another device, such as a mobile phone, through a cable. Electrical port  160  may also facilitate communication with battery pack  100  for other purposes such as configuring, testing, or updating software or firmware. 
     In some configurations, electrical port  160  may be implemented in the form of an attached cable having an electrical connector at an end of the cable. In some examples, battery pack  100  may also operate as a charging base or include some or all of the charging base functions. 
       FIG. 2  shows a bottom perspective view of battery pack  100  and illustrates electrical contacts  152  on the bottom of battery pack  100 . Electrical contacts  152  may be any type of electrical contacts, probes, pins, prongs, and/or pads for making electrical contact to another device. Electrical contacts  152  may be spring loaded, movable, and/or have play for more easily and reliably making contact to other devices. While five electrical contacts are illustrated, other quantities are possible including two, three, four, six, seven, or more.  FIG. 2  also illustrates bottom alignment guide  132  which is discussed in further detail below. In addition to positioning, aligning, or registering battery pack  100  with another device generally, bottom alignment guide  132  may serve to align electrical contacts  152  with a complementary set of contact, pins, sockets, pads, or probes. Electrical contacts  152  may be configured to engage, contact, or mate with electrical contacts  154  of another instance of battery pack  100 . Electrical contacts  152  and electrical contacts  154  may be complementary. In one example, one of electrical contacts  152  and  154  may be pins while the other of electrical contacts  152  and  154  are contacts, sockets, or pin receptacles configured for being contacted by the pins. 
       FIG. 3  illustrates battery pack  100  wirelessly charging an electronic device  213  which is sitting on top surface  112  of battery pack  100 . Electronic device  213  may be any type of cell phone, smart phone, smartphone, personal digital assistant (PDA), tablet computer, laptop computer, phablet, wearable device, gaming device, global positioning satellite (GPS) receiver, and/or multimedia player which includes a rechargeable battery and wireless charging capabilities. Wireless charging permits electrical power to be transferred from or through an inductive coil of one device to an inductive coil of another device without any physical or cabled electrical interconnection between the two devices or coils. A number of wireless charging standards have developed for charging portable electrical or electronic devices. These standards include, but are not limited to, Qi, PMA, and Powermat, as well as proprietary standards. The devices and techniques disclosed herein may be used with these or any other wireless charging standard, format, system, and/or protocol, including combinations thereof. Furthermore, wireless charging may be implemented using one or more resonant inductive coupling or charging techniques. 
       FIG. 4  illustrates a charging base  410  that may be used with any of the rechargeable battery pack systems disclosed herein. In addition to the elements visible in  FIG. 4 , charging base  410  may include internal components inside housing  411 . These internal components may include a printed circuit board, electrical components, discrete components, electrical circuitry, analog components, digital components, a microprocessor, a microcontroller, memory, a voltage controller, a voltage booster, a current limiter, a transformer, electromechanical connectors, an electrical coil, an inductive electrical coil, a modulator, a demodulator, an rf transmitter, an rf receiver, an antenna, a filter, a mixer, and/or an amplifier. 
     Charging base  410  may include or may be removably attachable to a cable  420  for receiving electrical power and/or data communications from another device. In one example, charging base  410  may receive power from an AC line power source, a wall charger, and/or a transformer. Cable  420  may be removable from charging base  410  and may attach to charging base  410  at or through an electrical port or connector on charging base  410 . 
     Charging base  410  also includes electrical contacts  454 . Electrical contacts  454  of charging base  410  are used for conducting electrical power and or data signals to battery pack  100  through electrical contacts  152 . Electrical contacts  454  may be any type of conductive electrical contacts, probes, pins, and/or pads for making electrical contact to another device, such as battery pack  100 . Electrical contacts  454  may be spring loaded, flexible, movable, and/or have play or travel for more easily and reliably making contact to other devices. While five electrical contacts are illustrated, other quantities are possible including two, three, four, six, seven, or more. 
     Charging base  410  also includes top alignment guide  430  for engaging or interfacing with bottom alignment guide  132  of battery pack  100  for orienting battery pack  100  with charging base  410  when battery pack  100  is set on top of charging base  410 . Bottom alignment guide  132  and top alignment guide  430  may comprise any combination of one or more grooves, channels, slots, recesses, receptacles, ridges, fins, protrusions, tabs, pins, and/or other alignment features for aligning, orienting, and/or registering the two devices to each other. It is not necessary that these alignment features extend all the way around and edge or perimeter of the devices. 
     In some examples, the battery packs and/or charging bases disclosed herein may include one or more magnets for aligning the devices and the respective sets of electrical contacts when they are in a stacked configuration. The magnets may extend from an area near a top surface of the rechargeable battery pack to an area near a bottom surface of the rechargeable battery pack such that teach magnet attract objects proximate both the top and bottom surfaces of the rechargeable battery pack. The magnets may also serve to improve engagement of the electrical contacts and may cause one or more floating or spring-loaded electrical contacts to be depressed to improve the reliability of the associated electrical connection. 
     In some cases, charging base  410  may also include a button or switch, similar to button  120 , for activating one or more features of charging base  410 . Charging base  410  may also include one or more display elements, similar to display elements  140  for indicating a status, mode, configuration, and/or state of charging base  410 . 
       FIG. 5  illustrates a battery pack system including charging base  410  with four battery packs stacked on top: battery pack  100 , battery pack  101 , battery pack  102 , and battery pack  103 . Battery packs  101 ,  102 , and  103  are each examples of battery pack  100 . More or fewer battery packs are possible. Beneficially, battery packs  100 - 103  can all be simultaneously charged while stacked together as illustrated in  FIG. 5 . A user may simply pick up the top battery pack from the stack and temporarily use it in another location to wirelessly charge an electronic device, as illustrated in  FIG. 3 . 
     In one example, the stack of battery packs in  FIG. 5  is kept in a conference room, meeting room, or work area. Meeting attendees may pick up one of the battery packs for use during a meeting and return it to the stack when they leave. Beneficially, the battery packs are easily moved and used because they are not attached to the base by a cable and are convenient to operate because they charge a phone wirelessly. Further, when the battery packs are not in use and returned to the stack they are automatically recharged. Electrical power is transferred up through the stack to each of battery packs  100 - 103  through electrical contacts  454  of charging base  410  and electrical contacts  152  and electrical contacts  154  on each of battery packs  100 - 103 . In another use model, the stack is kept in a restaurant or coffee shop and customers borrow or rent one of the battery packs  100 - 103  for use while they are present. In yet another use model, a family has one or more charging bases in a central location(s) in their home and the battery packs may be temporarily taken for use in different areas of the house. 
     When battery pack  100  is stacked on top of charging base  410  or on top of one of battery packs  101 - 103 , the electrical contact that is formed between the two may include one or more pins or conductors for establishing communication between the two. In other words, one or more of electrical contacts  154  and/or electrical contacts  454  may make contact with electrical contacts  152  of a battery pack placed on top in order to establish communication between them. This communication may occur using any known format, protocol, standard, message structure, sequence, or modulation type common to the two devices. The communication may be conducted using any type of known electrical signals, data communication signals, binary signals, and/or analog signals. As described in further detail below, the communication may serve a variety of purposes. In some configurations, some of electrical contacts  152  and electrical contacts  154  may be dedicated to data communication while others are dedicated to power transfer. In other configurations, some of electrical contacts  152  and electrical contacts  154  may be used for both communication and power transfer purposes, either through time division multiplexing or by superimposing or modulating the communication signals while power transfer is taking place. 
     In one example, communication may be established between a newly placed battery pack and a device it is placed on top of (either another battery pack or a charging base) before electrical charging power is provided to the top battery pack. In this way, charging power may not be available at electrical contacts  154  and/or  454  continuously and/or may not be available until the communication has been established. Beneficially, this reduces the chance that a metal object may inadvertently come into contact with and/or short any of electrical contacts  154  or  454  thereby reducing the chance of damage to the product, accidental discharge, interfacing to an incompatible product, sparking, and/or fire. In other words, the power transfer contacts on top of the device may not be “live” until an acceptable device is placed on top and communication is established. Using this method, charging power may only be available at the power contacts of electrical contacts  154  and/or  454  only after the communication contacts of electrical contacts  154  and/or  454  have come into contact with each other and communication established with a compatible battery pack. 
     Once communication is established with a device placed above, the battery pack may activate, power, or enable a switch, a relay, a field effect transistor (FET), or similar device for selectively activating or turning on power to electrical contacts  154 . Some of electrical contacts  154  may be active for purposes of performing the communication before the contacts carrying the electrical power are activated and/or before electrical power is made available at any of electrical contacts  154 . In other configurations, the charging power conducted through a battery pack (from the charging base to a battery pack that is higher in the stack) may not be switchable and may be available at electrical contacts  154  any time it is provided at electrical contacts  152 . Further, the battery pack may temporarily turn off or disable the wireless charging coil or circuitry when communication is established with a battery back above as it is known that the battery pack will not be wirelessly charging an electronic device while the other battery pack is present above. 
     In another example, communication may be established before charging power is provided from a charging base or a battery pack or to another battery pack placed on top in order to offer further control of the charging system. For example, a coffee shop or retail store may provide/rent battery packs for use in their establishment. However, the retailer may wish to deter people from taking the battery packs from the establishment and attempting to use them elsewhere and/or use them with another instance of a charging system at home or work. Therefore, the retailer may program the battery pack or system to work only with specified charging bases and/or battery packs. Each battery pack and/or charging base may have a unique identifier, identification number, identity code, key, or serial number. Controlled communication and one or more types of authentication or verification between the devices may also limit use of the devices with devices made or provided by other manufacturers. Many types of authentication are possible including serial number verification, passcode verification, single-factor authentication, two-factor authentication, as well as cryptographic techniques including public and private keys. 
     In some examples, the devices may be programmed to work with only certain other charger bases and/or battery packs even though they may be otherwise mechanically compatible. This feature may discourage theft of the devices because they will not operate with the other charging bases or battery packs, even though they may be a same brand, make, and/or type. For example, a company who purchases the products may program the products to work only with the other products they own (as identified by the unique identifiers, identity codes, or serial numbers) such that they cannot be used with the same make and/or model of these products owned by another party. The unique identifiers, identity codes, or serial numbers may be encoded, embedded in other data, or otherwise transformed such that the information cannot be easily recovered by simply monitoring or recording the communications between the devices. In other words, any combination of charging base and battery pack or pair of battery packs may perform a data handshake to verify that they are intended to be compatible or interoperable devices before one or more of the power contacts are activated for transferring electrical power. 
     In one specific example, there are two types of battery packs and two types of charging bases. One of the types of battery packs may be operable with only one of the types of charging bases while the other type of battery pack is only operable with the other type of charging base. Alternately, one of the types of battery packs may be operable with both types of charging bases, while the other type of battery pack is only operable with only one of the types of charging bases. The battery packs and/or charging base with interoperability that is more limited may be sold to customers using them in business, corporate, or public environments where theft may be an issue. In this way, users will be deterred from taking these battery packs home or to other locations because the battery packs will not be operable with the other (seemingly similar) charging base they may have at home and will become useless once discharged. In other words, the battery packs that are used in public or business settings may be only operable with a specific charging base or with a specific type of charging base or group of charging bases. 
     In yet another example, the battery packs disclosed herein may be programmable to work for only a certain period of time after being removed from the charging base. In other words, the battery pack may only provide charging power for 30 minutes, 1 hour, or 2 hours, etc. after being removed from the charging base even though it may not be fully discharged. The battery pack may have to be returned to the base to initiate or activate another use session. In this way, a retailer can control how long a customer uses the device and possibly indirectly the length of customer visits. This type of use limitation further deters removal of the battery pack from the premises. In some cases, such as in a coffee shop, the battery pack may be activated for further use or for another use session after another purchase is made. 
     Some examples of the battery packs discussed herein have standardized charging cables or ports, such as a USB port, such that they can be individually recharged through the port or cable in addition to being charged in the stack. However, battery packs that are used in public or business settings and may be subject to theft may not include a charging port or cable. This configuration further limits the ability to recharge the battery pack other than with a specific type of charging base and deters removal of the device from the premises because it cannot be recharged other than with the specific charging base, specific type of charging base, or specifically programmed charging base. 
     In other variations, there may be three, four, five, or more groups or types of devices (charging bases and battery packs) that are interoperable within the group, but not with charging bases or battery packs from other groups. The interoperability, or lack thereof, may be controlled by transmitting and/or exchanging of the unique identifiers, identification numbers, identity codes, or serial numbers. In these examples, each device may have a unique number or code and only certain groups of numbers or codes are interoperable. In another variation, the interoperable devices may share a same unique number or code. A device owner may be able to set their own code(s) such that only their devices are interoperable with each other further deterring theft or relocation of the devices. Many variations are possible. 
     In some configurations, the charging power received at each of the battery packs in a charging stack may be provided by only the charging base. In other words, referring to  FIG. 5 , any electrical charging power received by any of battery packs  100 - 103  may only be supplied by charging base  410 . Battery packs  100 - 102  may be configured to not provide electrical power to other devices in the stack from their own rechargeable batteries. In this way, each of battery packs  100 - 103  may be configured to use the power it receives from the device below it in the stack in only two ways. First, it may use some of the received power to charge its own rechargeable battery. Second, it may pass on some of the received power to the device above it through electrical contacts  154 . As described herein, making the power available to the device above may be subject to detecting and/or verification of the device above before the power is transferred to electrical contacts  154 . In this way, the stacked devices may effectively create a power “bus” extending from charging base  410  up through the stack of battery packs  100 - 103 . Each of battery packs  100 - 103  may draw power from the “bus” as needed, but “may not supply power to the bus as it passes through the battery pack. In addition, as described herein, each battery pack may optionally having the ability to switch the “bus” on and off depending on whether a proper device is detected above. 
     In other configurations, in contrast to the configuration discussed above, any one of battery packs  100 - 103  may be configured to charge another of battery packs  100 - 103  without the use or presence of a charging base. In other words, any one of battery packs  100 - 103  may be configured to charge another of battery packs  100 - 103  using its own internal rechargeable battery and/or using power received through a cable connected directly to the battery pack. 
     In some configurations, electronic device  213  may also be placed on top of battery pack  103  and wirelessly charged by battery pack  103  while battery pack  103  is stacked on one or more of the other battery packs or charging base (not illustrated). In other words, any of the battery packs may be capable of simultaneously being charged by charging base  410  through the stack, as well as wirelessly providing charging power to an electronic device, such as electronic device  213 . 
     One or more software applications or sets of non-transitory computer instructions may be executed on any of the devices discussed herein having a microprocessor in order to program or configure any of the features or capabilities disclosed herein. The software application(s) may also be used to check the status of the devices, monitor their location, determine their health, determine their mode or status, determine their battery health or condition, and/or otherwise manage the devices in a pay-for-use or rental configuration. In some examples, a battery pack may be programmed or configured to only work for a specified duration or period of time before it must be reset or re-enabled by the owner. In this way, a device owner can limit the usage by someone borrowing or renting the device and further discourage the person from taking it to another location. 
       FIG. 6  illustrates charging base  410  charging electronic device  213  directly and wirelessly. In addition to being able to charge any one or more of battery packs  100 - 103  which may be placed on it through electrical contacts  454  (as illustrated in  FIG. 5 ), charging base  410  may also include wireless charging circuitry, similar to that of battery packs  100 - 103 , enabling it to wirelessly charge an electronic device which is placed upon it. In this way, charging base  410  can be used to directly charge an electronic device even if all of the associated battery packs are already in use or are currently discharged. In some examples, charging base  410  may not enable, activate, and/or power the wireless charging circuitry or coil until an electronic device is detected in proximity to the top surface of the charging base. Any of the battery packs disclosed herein may behave in a same or similar matter. 
       FIG. 7  illustrates a stand  710  with electronic device  213  and battery pack  100 . Stand  710  may be configured to hold electronic device  213  in an upright, angled, tilted, or viewing position to enable a user to easily see the screen of the device while it is sitting on a table, desk, tray, or other substantially horizontal surface. Stand  710  may also hold battery pack  100  in a similar position such that it is adjacent to electronic device  213 . This configuration enables battery pack  100  to wirelessly charge electronic device  213  while it is sitting in or on stand  710 . Each of electronic device  213  and battery pack  100  may be temporarily removable from stand  710  while the other remains in place. 
     In some configurations, stand  710  may be a mechanical stand only and may include one or more openings and/or channels for routing a separate cable (not illustrated) to one or both of electronic device  213  and battery pack  100 . In other configurations, stand  710  may include electrical components and may provide power to one or both of electronic device  213  and battery pack  100 . In some configurations, power may be provided to stand  710  through a cable (not illustrated) which may be permanently attached or may be removably attachable to stand  710 . 
       FIG. 8  illustrates a close-up view of the variation in which stand  710  includes electrical contacts  754  for making contact with electrical contacts  152  of battery pack  100  when it is resting in slot  742  (in a configuration similar to that of  FIG. 7 ). Electrical contacts  754  may provide power from a rechargeable battery contained in stand  710  or from an external power source that is connected to stand  710 . Similarly, stand  710  may also contain electrical contacts or an electrical connector that interfaces directly to electronic device  213  when it is resting in slot  742 . Stand  710  may use one or more magnets for aligning and facilitating good electrical contact with other devices. 
     Any combination of the devices, apparatuses, battery packs, charging bases, stands, and/or software disclosed herein may be configured in the form of a system or kit. A kit may have a single battery pack, multiple battery packs, a charging base, multiple charging bases, or any number of battery packs along with any number of charging bases. 
     Some or all of the steps and operations associated with the techniques introduced here may be performed by hardware components or may be embodied in non-transitory machine-executable instructions that cause one or more computer processors programmed with the instructions to perform the steps. Alternatively, the steps may be performed by a combination of hardware, software, and/or firmware. 
     The apparatuses, systems, methods, techniques, and components described herein are meant to exemplify some types of possibilities. In no way should the aforementioned examples limit the scope of the invention, as they are only exemplary embodiments. 
     The foregoing disclosure has been presented for purposes of illustration and description. Other modifications and variations may be possible in view of the above teachings. The examples described in the foregoing disclosure were chosen to explain the principles of the concept and its practical application to enable others skilled in the art to best utilize the invention. It is intended that the claims be construed to include other alternative embodiments of the invention except as limited by the prior art. 
     The phrases “in some embodiments,” “according to some embodiments,” “in the embodiments shown,” “in other embodiments,” “in some examples,” “in some cases,” “in some situations,” “in one configuration,” “in another configuration” and the like generally mean that the particular feature, structure, or characteristic following the phrase is included in at least one embodiment of the present invention and/or may be included in more than one embodiment of the present invention. In addition, such phrases do not necessarily refer to the same embodiments or different embodiments.