PATENT DOCUMENT

Publication Number: US-9705115-B2
Application Number: US-201213627944-A
Country: US
Kind Code: B2

Title: Battery structure and integration

Abstract:
A portable electronic device is described. This portable electronic device includes an external housing with a cavity defined by an edge. A keyboard, having a front surface and a back surface, is disposed in the cavity with the front surface facing the external housing. Moreover, a tray is disposed over the back surface of the keyboard, and is mechanically coupled to the external housing adjacent to the edge. Furthermore, battery cells are mechanically coupled to an opposite side of the tray from the back surface of the keyboard. The tray may allow the battery cells to be removed from the portable electronic device without damaging the keyboard. In addition, the tray may increase the compression strength and/or the bending strength of the portable electronic device.

Claims:
What is claimed is: 
     
       1. A portable electronic device, comprising:
 a housing that carries operational components; 
 an input device carried by the housing; 
 a tray removably carried by the housing inside the housing, the tray comprising sidewalls capable of increasing an overall compressive strength of the portable electronic device, wherein the tray is removable from the housing without damaging either the housing or the input device; and 
 a battery cell arranged to store electrical energy for use by the operational components, wherein the battery cell is secured to a surface of the tray and is removable with the tray from the housing, wherein when the tray and the battery cell are removed and electrically detached from the portable electronic device, the portable electronic device remains operable. 
 
     
     
       2. The portable electronic device of  claim 1 , further comprising multiple battery cells that are secured to separate areas of the tray. 
     
     
       3. The portable electronic device of  claim 2 , further comprising an interposer board, wherein the multiple battery cells are electrically connected to the interposer board and the interposer board is configured to provide a common ground for the multiple battery cells. 
     
     
       4. The portable electronic device of  claim 3 , further comprising a battery-management circuit and a motherboard. 
     
     
       5. The portable electronic device of  claim 4 , wherein the interposer board is positioned between the battery management circuit and the motherboard. 
     
     
       6. The portable electronic device of  claim 5 , wherein the battery-management circuit is electrically coupled to the multiple battery cells and includes an integrated circuit with control logic configured to monitor the multiple battery cells and regulate charging and discharging of the multiple battery cells. 
     
     
       7. The portable electronic device of  claim 5 , wherein the interposer board includes spring connectors for electrically connecting the battery management circuit and the motherboard. 
     
     
       8. The portable electronic device of  claim 7 , wherein the battery-management circuit is configured to disable itself from subsequent use upon disconnection from the interposer board. 
     
     
       9. The portable electronic device of  claim 8 , wherein the battery-management circuit is further configured to disable upon receipt of an instruction from the motherboard. 
     
     
       10. The portable electronic device of  claim 9 , wherein the instruction is transmitted via at least one spring connector of the spring connectors. 
     
     
       11. The portable electronic device of  claim 2 , wherein the multiple battery cells include lithium-ion batteries. 
     
     
       12. The portable electronic device of  claim 7 , wherein at least two spring connectors of the spring connectors have different height dimensions. 
     
     
       13. The portable electronic device of  claim 1 , further comprising: subsets of battery cells, wherein each subset of the subsets has a substantially equal capacity. 
     
     
       14. The portable electronic device of  claim 13 , wherein each subset of the subsets includes battery cells of different dimensions. 
     
     
       15. The portable electronic device of  claim 14 , further comprising a separate battery cell that is mechanically coupled to a surface of the housing and connected to a main power bus such that power is provided to the operational components when the tray is removed. 
     
     
       16. The portable electronic device of  claim 1 , wherein the input device is a keyboard that includes backlighting elements. 
     
     
       17. The portable electronic device of  claim 1 , wherein the sidewalls are adjacent to lateral sides of the at least one battery cell. 
     
     
       18. The portable electronic device of  claim 1 , wherein the sidewalls extend away from the input device. 
     
     
       19. The portable electronic device of  claim 1 , wherein the sidewalls are configured to increase a bending strength of the portable electronic device. 
     
     
       20. A base portion of a computer device having a display portion pivotally coupled to the base portion, the base portion comprising:
 a housing; 
 a tray removably carried by the housing inside the housing, the tray having sidewalls that cooperate to define a cavity; 
 a first battery cell carried by the tray in the cavity; and 
 a second battery cell carried by the housing outside the tray, 
 wherein the first battery cell is removable with the tray from the housing without damaging either the housing or a component of the computer device, and the computer device remains operable when the first battery cell is removed and electrically detached from the computer device. 
 
     
     
       21. The base portion of  claim 20 , wherein the first battery cell and the second battery cell are electrically coupled to a battery-management circuit. 
     
     
       22. The base portion of  claim 21 , wherein the battery-management circuit is electrically coupled to a motherboard. 
     
     
       23. The base portion of  claim 22 , wherein an interposer circuit board is positioned between the battery management circuit and the motherboard. 
     
     
       24. The base portion of  claim 23 , wherein the interposer circuit board is configured to provide a common ground for the first battery cell and the second battery cell. 
     
     
       25. The base portion of  claim 20 , wherein the battery management circuit regulates charging and discharging of the first and second battery cells. 
     
     
       26. The base portion of  claim 20 , wherein the sidewalls increase an overall compressive strength of the computer device.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims priority under 35 U.S.C. §119(e) to: U.S. Provisional Application Ser. No. 61/656,727, entitled “Battery Structure and Integration,” by Ron A. Hopkinson, Brett W. Degner, and Robert S. Murphy, filed on Jun. 7, 2012; U.S. Provisional Application Ser. No. 61/656,744, entitled “Detachment Mechanism for Battery Removal,” by Christiaan A. Ligtenberg, Matthew P. Casebolt, Robert S. Murphy, Ron A. Hopkinson, and Peter M. Arnold, filed on Jun. 7, 2012; and U.S. Provisional Application Ser. No. 61/656,700, entitled “Technique for Disabling a Power Supply,” by Christiaan A. Ligtenberg, Eric A. Knopf, Matthew P. Casebolt, Peter M. Arnold, Ron A. Hopkinson, and Robert S. Murphy, filed on Jun. 7, 2012, the contents of each of which are herein incorporated by reference. 
     This application is also related to: U.S. Patent Application Ser. No. 61/656,721, entitled “External Battery-Management Module,” by Christiaan A. Ligtenberg, Ron A. Hopkinson, and Robert S. Murphy, filed Jun. 7, 2012; U.S. Patent Application Ser. No. 61/656,709, entitled “Different-Sized Battery Cells with Common Capacity,” by Christiaan A. Ligtenberg, Robert S. Murphy, Brett W. Degner, Ron A. Hopkinson, Eugene Kim, Peter M. Arnold, and Jim Hwang, filed Jun. 7, 2012; and U.S. Patent Application Ser. No. 61/656,739, entitled “Cableless Battery Integration,” by Ron A. Hopkinson, Eric A. Knopf, Eugene Kim, Peter M. Arnold, Jim Hwang, and Matthew P. Casebolt, filed Jun. 8, 2012, the contents of all of which are herein incorporated by reference. 
    
    
     BACKGROUND 
     Field 
     The described embodiments relate to techniques for integrating batteries in portable electronic devices. 
     Related Art 
     The increasing functionality of portable electronic devices is placing commensurate demands on the batteries which are used to power these portable electronic devices. More specifically, the increasing density of circuits in integrated circuits, the increasing clock frequencies and the growing number of software applications executing on portable electronic devices are increasing their demand for power. However, the rate of growth in the energy density of batteries has not kept pace with the increasing demand for power. Moreover, size and weight constraints in portable electronic devices limit the number and size of the battery cells, and thus, their total capacity. 
     Furthermore, it can be difficult to address these challenges using existing battery organizations. For example, as shown in  FIG. 1 , which presents a block diagram of an existing battery  100  that includes battery cells  110  and a battery-management module  112  or battery-management circuit board (which monitors battery cells  110 , and regulates charging and discharging of battery cells  110 ). These components are contained within a battery-pack housing  114  for ease of handling and to prevent damage to battery cells  110 . However, this configuration consumes valuable space and, therefore, can restrict the total capacity of the battery cells. 
     SUMMARY 
     The described embodiments include a portable electronic device with an external housing that includes a cavity defined by an edge. A keyboard, having a front surface and a back surface, is disposed in the cavity with the front surface facing the external housing. Moreover, a tray, disposed over the back surface of the keyboard, is mechanically coupled to the external housing adjacent to the edge of the cavity. Furthermore, battery cells are mechanically coupled to an opposite side of the tray from the back surface of the keyboard. 
     Note that the tray may be mechanically coupled to the external housing screws. Moreover, the battery cells may be mechanically coupled to the tray by a mechanical coupling mechanism. For example, the mechanical coupling mechanism may include two outer layers surrounding an inner layer, and the inner layer may have a lower sheer strength than either of the outer layers. Alternatively or additionally, the mechanical coupling mechanism may include an adhesive layer. 
     In some embodiments, the portable electronic device includes a battery-management circuit board electrically coupled to the battery cells. This battery-management circuit board may include an integrated circuit with control logic that monitors the battery cells and regulates charging and discharging of the battery cells. Note that the battery cells (such as lithium-ion batteries) and the battery-management circuit board may constitute a battery. Moreover, the battery-management circuit board may be electrically coupled to the battery cells by a power bus. Furthermore, the battery cells may not be enclosed in a common battery-pack housing so that the battery cells are mechanically separate from each other, and the battery-management circuit board may be external to the battery cells and may not be enclosed in the battery-pack housing. Thus, the portable electronic device may exclude the battery-pack housing. 
     Additionally, the portable electronic device may include a motherboard. The battery-management circuit board may have a top surface and a bottom surface, where the bottom surface includes electrical connectors electrically coupled to the motherboard positioned beneath the battery-management circuit board. These electrical connectors may provide power and ground connections between the battery-management circuit board and the motherboard. 
     Moreover, the portable electronic device may include an interposer. Electrical connectors on the interposer may electrically couple the battery-management circuit board to the motherboard, and the bottom surface of the battery-management circuit board may include mechanical features that align the battery-management circuit board and the interposer. Furthermore, the motherboard may include a top surface, where the top surface of the motherboard includes mechanical features that align the motherboard and the interposer. 
     In some embodiments, the keyboard includes back-lighting elements disposed on the back surface of the keyboard. 
     Furthermore, the tray may include sidewalls. In this way, the tray may increase a compressive strength of the portable electronic device and/or a bending strength of the portable electronic device. 
     In some embodiments, the external housing and the tray are made of metal. 
     Another embodiment provides a portable electronic device having: an external housing; a battery cell mechanically coupled to the external housing by a mechanical coupling mechanism; and a tab mechanically coupled to a side of the battery cell. When pulled on, the tab conveys a sheer force to the mechanical coupling mechanism to detach the battery cell from the external housing. 
     The mechanical coupling mechanism may include two outer layers surrounding an inner layer, where the inner layer has a lower sheer strength than either of the outer layers. For example, the outer layers may include an adhesive. Furthermore, the inner layer may include a cross-linked foam. More generally, the inner layer may be thermally set. 
     In some embodiments, the portable electronic device includes a battery-management circuit board. This battery-management circuit board may include an integrated circuit with control logic that monitors the battery cell and that regulates charging and discharging of the battery cell. Moreover, the battery-management circuit board may be external to the battery cells and may not be enclosed in a battery-pack housing. Thus, the portable electronic device may exclude the battery-pack housing. 
     Alternatively or additionally, the portable electronic device may include a detachment mechanism embedded in the mechanical coupling mechanism proximate to an edge of the mechanical coupling mechanism. When pulled on, the detachment mechanism initiates singulation of the mechanical coupling mechanism to detach the battery cell from the external housing. For example, the detachment mechanism may include a string, such as a string made of Kevlar® (from the E. I. du Pont de Nemours and Company of Wilmington, Del.). Moreover, the detachment mechanism may have a thickness approximately the same as that of the mechanical coupling mechanism. In these ways, the detachment mechanism may prevent bending of (and thus damage to) the battery cell when the battery cell is detached from the external housing. 
     Another embodiment provides a method for removing the battery cell from the portable electronic device. During the method, a sheer force is applied to the mechanical coupling mechanism that mechanically couples the battery cell to the external housing of the portable electronic device using the tab that is mechanically coupled to the side of the battery cell. Then, after the battery cell is detached from the external housing, the battery cell is removed from the portable electronic device. 
     Another embodiment provides a method for removing the battery cell from the portable electronic device. During the method, the mechanical coupling mechanism that mechanically couples the battery cell to the external housing of the portable electronic device is singulated using the detachment mechanism that is embedded in the mechanical coupling mechanism. Then, after the battery cell is detached from the external housing, the battery cell is removed from the portable electronic device. 
     Another embodiment provides a battery-management circuit board having a substrate, with an integrated circuit disposed on the substrate. This integrated circuit includes: an interface circuit that receives an instruction code; and control logic that performs a disabling procedure when the instruction code is received. During the disabling procedure, the control logic: provides a discharge signal to battery cells electrically coupled to the battery-management circuit board; receives confirmation signals from the battery cells that the battery cells are discharged below a threshold; and permanently disables the battery-management circuit board. 
     Note that the threshold may be about 5% of capacity of each of the battery cells. 
     In some embodiments, prior to permanently disabling the battery-management circuit board, the control logic stores a timestamp and a discharge state of the battery cells in a memory disposed on the battery-management circuit board. 
     Moreover, permanently disabling the battery-management circuit board may involve a software fuse and/or a hardware fuse. 
     Furthermore, during normal operation, the control logic monitors the battery cells and regulates charging and discharging of the battery cells. 
     Another embodiment provides a portable electronic device that includes: the battery cells (such as lithium-ion batteries); and the battery-management circuit board electrically coupled to the battery cells. 
     Another embodiment provides a method for disabling a power supply. During operation, control logic on the battery-management circuit board in the power supply receives the instruction code. In response to the instruction code, the control logic performs the disabling procedure. This disabling procedure includes the operations of: providing the discharge signal to the battery cells in the power supply that are electrically coupled to the battery-management circuit; receiving the confirmation signals from the battery cells that the battery cells are discharged below the threshold; and permanently disabling the battery-management circuit board. 
     In some embodiments, prior to permanently disabling the battery-management circuit board, the disabling procedure involves storing the timestamp and the discharge state of the battery cells in the memory disposed on the battery-management circuit board. 
     Moreover, during normal operation, the control logic performs the operations of: monitoring the battery cells; and regulating charging and discharging of the battery cells. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         FIG. 1  is a block diagram illustrating an existing battery. 
         FIG. 2  is a block diagram illustrating a top view of a power supply in a portable electronic device in accordance with an embodiment of the present disclosure. 
         FIG. 3  is a block diagram illustrating a top view of a power supply in a portable electronic device in accordance with an embodiment of the present disclosure. 
         FIG. 4  is a block diagram illustrating a side view of an interposer in the portable electronic device of  FIG. 2 or 3  in accordance with an embodiment of the present disclosure. 
         FIG. 5  is a block diagram illustrating a top view of the interposer of  FIG. 4  in accordance with an embodiment of the present disclosure. 
         FIG. 6  is a block diagram illustrating a side view of the interposer of  FIGS. 5 and 6  in accordance with an embodiment of the present disclosure. 
         FIG. 7  is a drawing illustrating electrical coupling of spring connectors on the interposer of  FIG. 4  in accordance with an embodiment of the present disclosure. 
         FIG. 8  is a drawing illustrating electrical coupling of battery cells and a battery-management circuit board in the power supply of  FIG. 2  in accordance with an embodiment of the present disclosure. 
         FIG. 9  is a drawing illustrating electrical coupling of battery cells and a battery-management circuit board in the power supply of  FIG. 3  in accordance with an embodiment of the present disclosure. 
         FIG. 10  is a block diagram illustrating a side view of a battery cell in the portable electronic device of  FIG. 2 or 3  in accordance with an embodiment of the present disclosure. 
         FIG. 11  is a block diagram illustrating a top view of a mechanical coupling mechanism in the portable electronic device of  FIG. 2 or 3  in accordance with an embodiment of the present disclosure. 
         FIG. 12  is a block diagram illustrating a side view of a mechanical coupling mechanism in the portable electronic device of  FIG. 2 or 3  in accordance with an embodiment of the present disclosure. 
         FIG. 13  is a block diagram illustrating a side view of a portable electronic device in accordance with an embodiment of the present disclosure. 
         FIG. 14  is a block diagram illustrating a top view of a portable electronic device in accordance with an embodiment of the present disclosure. 
         FIG. 15  is a block diagram illustrating a battery-management circuit board in the portable electronic device of  FIG. 2 or 3  in accordance with an embodiment of the present disclosure. 
         FIG. 16  is a flowchart illustrating a method for operating a power supply in a portable electronic device in accordance with an embodiment of the present disclosure. 
         FIG. 17  is a flowchart illustrating a method for operating a power supply in a portable electronic device in accordance with an embodiment of the present disclosure. 
         FIG. 18  is a flowchart illustrating a method for operating a power supply in a portable electronic device in accordance with an embodiment of the present disclosure. 
         FIG. 19  is a flowchart illustrating a method for removing a battery cell from a portable electronic device in accordance with an embodiment of the present disclosure. 
         FIG. 20  is a flowchart illustrating a method for removing a battery cell from a portable electronic device in accordance with an embodiment of the present disclosure. 
         FIG. 21  is a flowchart illustrating a method for disabling a power supply in accordance with an embodiment of the present disclosure. 
     
    
    
     Note that like reference numerals refer to corresponding parts throughout the drawings. Moreover, multiple instances of the same part are designated by a common prefix separated from an instance number by a dash. 
     DETAILED DESCRIPTION 
       FIG. 2  presents a block diagram illustrating a top view of a power supply  210  (such as a battery) in a portable electronic device  200 . This power supply includes battery cells  212  (e.g., lithium-ion batteries) in separate locations that are electrically coupled by a power bus  218  to a battery-management circuit board  214  or battery-management module, which (as further described below with reference to  FIG. 15 ) includes an integrated circuit  216  with control logic that monitors battery cells  212  and regulates charging and discharging of battery cells  212 . Note that battery cells  212  are not enclosed in a common battery-pack housing so that battery cells  212  are mechanically separate from each other. Moreover, battery-management circuit board  214  is external to battery cells  212  and is not enclosed in the battery-pack housing. By excluding the battery-pack housing from power supply  210  (and, more generally, from portable electronic device  200 ), there may be more space available to expand the sizes, and thus the total capacities, of battery cells  212 . As described further below, this design choice may entail including additional features in portable electronic device  200  to integrate power supply  210 . 
     Portable electronic device  200  may include a motherboard  220  that includes additional integrated circuits (such as a processor and/or memory). As described further below with reference to  FIG. 4 , battery-management circuit board  214  may overlap motherboard  220 . For example, battery-management circuit board  214  may be positioned above motherboard  220 , and an interposer may provide power and ground connections between electrical connectors on battery-management circuit board  214  and motherboard  220 . 
     Another configuration of the battery cells is shown in  FIG. 3 , which presents a block diagram illustrating a top view of a power supply  310  in a portable electronic device  300 . 
     As noted previously, the battery-management circuit board may be electrically coupled to the motherboard via an interposer. This is shown in  FIG. 4 , which presents a block diagram illustrating a side view of an interposer  400  in portable electronic device  200  ( FIG. 2 ) or  300  ( FIG. 3 ). In particular, battery-management circuit board  214  has a top surface  410  and a bottom surface  412 . Bottom surface  412  includes electrical connectors  414  that electrically couple battery-management circuit board  214  to spring connectors  416  on a top surface  418  of substrate  408  in interposer  400 . These spring connectors are electrically coupled by vias  420  through substrate  408  to spring connectors  422  on a bottom surface  424  of substrate  408 . 
     Furthermore, motherboard  220 , which is positioned beneath battery-management circuit board  214 , has a top surface  426  and a bottom surface  428 . Top surface  426  includes electrical connectors  430  that electrically couple motherboard  220  to spring connectors  422 . 
     In an exemplary embodiment, spring connectors  416  and  422  (such as leaf-spring or cantilever fingers) each provide a dense set of 62 interconnects with a pitch of 1 mm. Moreover, each of the spring connectors may include gold deposited on a beryllium-copper base, and may be capable of conducting 1 A of current. Furthermore, interposer  400  may be capable of conducting 13 A of current in total. Note that substrate  408  may include an FR-4 fiberglass-reinforced epoxy-laminate sheet. One possible supplier of interposer  400  is Neoconix™ of Sunnyvale, Calif. 
     In order to facilitate proper assembly and alignment of battery-management circuit board  214 , interposer  400  and motherboard  220 , the portable electronic device may include mechanical features. In particular, bottom surface  412  and top surface  418  may include mechanical features  432 , such as mating or interlocking mechanical features (e.g., one or more pins or positive features and corresponding slots or negative features), which facilitate alignment of battery-management circuit board  214  and interposer  400  by preventing rotational misalignment. Similarly, bottom surface  424  and top surface  426  may also include mechanical features  434  that facilitate alignment of interposer  400  and motherboard  220 . 
     In addition, the portable electronic device may include stiffener mechanisms  436  (such as washers) disposed on top surface  410  and bottom surface  428 . These stiffener mechanisms may distribute a compressive mechanical coupling force (such as that associated with nuts and a screw through the entire structure, which are not shown in  FIG. 4 ) over top surface  410  and bottom surface  428 . This may be useful if battery-management circuit board  214  and/or motherboard  220  are thin. A typical thickness for battery-management circuit board  214  is between 0.5 and 1 mm, and a typical thickness for motherboard  220  is between 0.5 and 1.5 mm. Moreover, interposer  400  may have a thickness of 1.8 mm. 
     The electrical paths between battery-management circuit board  214  and motherboard  220  (i.e., electrical connectors  414 , spring connectors  416 , vias  420 , spring connectors  422 , and electrical connectors  430 ) may provide power and ground connections between battery-management circuit board  214  and motherboard  220 . This is shown in  FIG. 5 , which presents a block diagram illustrating a top view of interposer  400 . In particular, spring connectors  416  include a subset  510  that convey power signals. This subset may be divided in half into two groups, power connectors  512  and ground connectors  514 . (A similar segregation may occur in spring connectors  422 . In the discussion that follows, spring connectors  416  are used as an illustration.) 
     One challenge associated with interposer  400  is to ensure that it is fully mated and planar with battery-management circuit board  214  and motherboard  220  in  FIG. 4  before power is conveyed between battery-management circuit board  214  and motherboard  220 . To address this challenge, in addition to subset  510 , spring connectors  416  may include a dedicated subset  516  (such as 10 spring connectors) that convey monitoring signals for the power supply. Spring connectors in subset  516  may be disposed proximate to periphery  518  of top surface  418 , such as near the corners (and a similar subset of spring connectors  422  may be disposed proximate to the periphery of bottom surface  424  in  FIG. 4 ). This may increase the sensitivity of spring connectors in subset  516  to mechanical misalignment and non-planarity because these conditions can be difficult to achieve at periphery  518  (for example, a clamping or compressive mechanical coupling force may roll-off at periphery  518 ). 
     As shown in  FIG. 6 , which presents a block diagram illustrating a side view of the interposer  400 , spring connectors in subset  510  may have a vertical height  520  when activated, and spring connectors in subset  516  may have a vertical height  522  when activated. Vertical height  520  may be larger than vertical height  522  so that subset  510  is activated before subset  516  is activated. This may ensure that an electrical path between battery-management circuit board  214  and motherboard  220  in  FIG. 4  for the power signals is established before an electrical path between battery-management circuit board  214  and motherboard  220  in  FIG. 4  for the monitoring signals is established. For example, vertical height  520  may be 0.4 mm and vertical height  522  may be 0.3 mm. Note that, on average, a 4-gram force may be needed to activate each of spring connectors in subsets  510  and  516 , with a total force for interposer  400  of 2.5 kg. In this way, low impedance electrical connections for the power signals may be established before the monitoring signals are detected by control logic in the portable electronic device and, thus, before the power signals are conveyed between battery-management circuit board  214  and motherboard  220  in  FIG. 4 . 
     Detecting that the interposer  400  is fully mated and planar with battery-management circuit board  214  and motherboard  220  in  FIG. 4  may be facilitated by electrically coupling spring connectors in subset  516 . (In addition, subsets of spring connectors  422  may be similarly electrically coupled.) This is shown in  FIG. 7 , which presents a drawing illustrating electrical coupling of spring connectors  416  in subset  516  on interposer  400 . In particular, spring connectors in subset  516  may be electrically coupled to each other in a daisy-chain fashion so that, when these spring connectors are activated, an electrical path (E.P.)  710  is completed indicating that interposer  400  and battery-management circuit board  214  in  FIG. 4  are fully mated and planar (thereby ensuring that the portable electronic device can communicate with the power supply before the power is enabled). In addition, spring connectors in subset  516  may be electrically coupled to each other in a daisy-chain fashion so that, when these spring connectors are activated, an electrical path (E.P.)  712  is completed indicating that interposer  400  and motherboard  220  in  FIG. 4  are fully mated and planar. While not shown, spring connectors in a subset of spring connectors  422  that convey monitoring signals may also be electrically coupled to each other so that, when these spring connectors are activated, electrical path  710  is completed indicating that interposer  400  and battery-management circuit board  214  in  FIG. 4  are fully mated and planar, and electrical path  712  is completed indicating that interposer  400  and motherboard  220  in  FIG. 4  are fully mated and planar. 
     Because of space constraints in the portable electronic device, at least some of battery cells  212  ( FIGS. 2 and 3 ) may have different sizes and, thus, different capacities. However, while at least some of the battery cells may have different capacities, subsets of the battery cells may be electrically coupled to battery-management circuit board  214  ( FIGS. 2 and 3 ) in such a way that each of the subsets has the same total capacity or Watt-hours. This is shown in  FIG. 8 , which presents a drawing illustrating electrical coupling of battery cells  212  and battery-management circuit board  214  in power supply  210 . In this power supply, there are three subsets  810 , each of which includes the same number of battery cells (in this example, two) and a total voltage of 4.5 V. While subset  810 - 1  includes battery cells having the same capacity, subsets  810 - 2  and  810 - 3  include battery cells having different geometric sizes and, thus, different capacities. For example, battery cells  212 - 1  and  212 - 2  may each have a length of 127.00 mm, a width of 34.30 mm and a thickness of 6.67 mm. Moreover, battery cells  212 - 3  and  212 - 6  may each have a length of 60.00 mm, a width of 31.50 mm and a thickness of 9.40 mm, and battery cells  212 - 4  and  212 - 5  may each have a length of 75.77 mm, a width of 57.86 mm and a thickness of 9.59 mm. 
     Furthermore, electrical leads (E.L.s)  812 - 1  and  812 - 2  of a first polarity (such as negative or ‘−’) in battery cells in subset  810 - 1  may be electrically coupled in parallel to the electrical leads  814 - 3  and  814 - 4  of a second polarity (such as positive or ‘+’) in battery cells in subset  810 - 2 , and electrical leads  814 - 1  and  814 - 2  of the second polarity in battery cells in subset  810 - 1  may be electrically coupled in parallel to the electrical leads  812 - 5  and  812 - 6  of the first polarity in battery cells in subset  810 - 3 . Furthermore, electrical leads  812 - 3  and  812 - 4  of the first polarity in battery cells in subset  810 - 2  may be electrically coupled in parallel and/or electrical leads  814 - 5  and  814 - 6  of the second polarity in battery cells in subset  810 - 3  may be electrically coupled in parallel. In addition to providing subsets  810  with the same total capacity, this wiring configuration may step up the voltage provided by power supply  210 . 
       FIG. 9  presents a block diagram illustrating a similar wiring configuration or electrical coupling of battery cells  212  (having different positions and geometric sizes than in  FIG. 8 ) and a battery-management circuit board  214  in power supply  310  ( FIG. 3 ) so that the battery cells with different capacities can be arranged in subsets  810  that have the same total capacity. Note that battery cells  212 - 1  and  212 - 2  may each have a length of 93.62 mm, a width of 58.00 mm and a thickness of 6.08 mm. Moreover, battery cells  212 - 3  and  212 - 5  may each have a length of 65.00 mm, a width of 55.44 mm and a thickness of 7.90 mm, and battery cells  212 - 4  and  212 - 6  may each have a length of 94.01 mm, a width of 50.60 mm and a thickness of 8.12 mm. 
       FIG. 10  presents a block diagram illustrating a side view of a battery cell  1010  in portable electronic device  200  ( FIG. 2 ) or  300  ( FIG. 3 ), such as one of battery cells  212 - 3 ,  212 - 4 ,  212 - 5  and  212 - 6 . This battery cell may be mechanically coupled (for example, it may be directly bonded or adhered) to external housing  1012  (such as a top case of the portable electronic device) by a mechanical coupling mechanism  1014 . For example, mechanical coupling mechanism  1014  may include two outer layers  1016  surrounding an inner layer  1018 , where inner layer  1018  has a lower sheer strength than either of outer layers  1016 . In some embodiments, outer layers  1016  may include an adhesive. Furthermore, inner layer  1018  may include a cross-linked foam (such as that described in U.S. patent application Ser. No. 13/198,586, entitled “Adhesive Stack with a Central Shear Layer, by Mathew P. Casebolt, filed on Aug. 4, 2011, the contents of which are hereby incorporated by reference). More generally, inner layer  1018  may be thermally set, while outer layers  1016  may not be thermally set. This mechanical coupling mechanism may help ensure that the bond strength between battery cell  1010  and external housing  1012  is consistent (and can be tuned or controlled by the mechanical properties of inner layer  1018 ) and is time invariant (for example, it may not depend on a thermal history of portable electronic device  200  in  FIG. 2 or 300  in  FIG. 3 ). In this way, external housing  1012  can be used to provide additional mechanical support to the components (such as the battery cells) in the power supply when the battery-pack housing is excluded from portable electronic device  200  ( FIG. 2 ) or  300  ( FIG. 3 ), thereby reducing possible damage to the power supply. For example, mechanical coupling mechanism  1014  may ensure that portable electronic device  200  ( FIG. 2 ) or  300  ( FIG. 3 ) can withstand the acceleration/deceleration associated with a 60-in vertical drop. 
     However, because battery cell  1010  is not included in the battery-pack housing, it may be difficult to remove battery cell  1010  from portable electronic device  200  ( FIG. 2 ) or  300  ( FIG. 3 ) without damaging it. For example, when reworking portable electronic device  200  ( FIG. 2 ) or  300  ( FIG. 3 ), battery cell  1010  may be bent when it is detached from external housing  1012 . 
     To address this challenge, an optional tab  1020  may be mechanically coupled to a side  1022  of battery cell  1010 . When pulled on, optional tab  1020  may convey a sheer force to mechanical coupling mechanism  1014  to detach battery cell  1010  from external housing  1012 . For example, the sheer force may initiate a notch in inner layer  1018  that allows it to be delamined. 
     Instead of optional tab  1020  (or in addition to it), a different detachment mechanism may be used. This is shown in  FIG. 11 , which presents a block diagram illustrating a top view of mechanical coupling mechanism  1014  in portable electronic device  200  ( FIG. 2 ) or  300  ( FIG. 3 ). In particular, detachment mechanism  1110  may be embedded in mechanical coupling mechanism  1014  proximate to edge  1112  of mechanical coupling mechanism  1014 . When pulled on (or moved side-to-side in a sawing motion), detachment mechanism  1110  can initiate singulation of inner layer  1018  in a controlled manner with zero strain to detach battery cell  1010  from external housing  1012 . For example, detachment mechanism  1110  may include a string, such as a string made of Kevlar® (from the E. I. du Pont de Nemours and Company of Wilmington, Del.). As shown in  FIG. 12 , which presents a block diagram illustrating a side view of a mechanical coupling mechanism  1014  in portable electronic device  200  ( FIG. 2 ) or  300  ( FIG. 3 ), note that detachment mechanism  1110  may have a thickness  1210  (such as 0.14 mm) approximately the same as thickness  1212  of mechanical coupling mechanism  1014  (such as 0.15 mm). 
     In these ways, detachment mechanism  1110  may prevent bending of (and thus damage to) battery cell  1010  when battery cell  1010  is detached from external housing  1012 . This may allow rework of portable electronic device  200  ( FIG. 2 ) or  300  ( FIG. 3 ). 
     In portable electronic device  200  ( FIG. 2 ), battery cells  212 - 1  and  212 - 2  may be positioned on top of a back surface of a keyboard. If these battery cells are removed (such as during rework of a portable electronic device), this configuration can result in damage to back-lighting elements, such as light-emitting diodes (LEDs), on the back surface. In addition, battery cells  212 - 1  and  212 - 2  can be damaged by a compression force and/or bending of portable electronic device  200  ( FIG. 2 ). 
     These challenges may be addressed using a tray in the configuration shown in  FIG. 13 , which presents a block diagram illustrating a side view of a portable electronic device  1300 , such as portable electronic device  200 . In particular, this portable electronic device includes an external housing  1310  that includes a cavity  1312  defined by an edge  1314 . A keyboard  1316 , having a front surface  1318  and a back surface  1320 , is disposed in cavity  1312  with front surface  1318  facing external housing  1310 . As noted previously, keyboard  1316  may include back-lighting elements  1322  disposed on back surface  1320 . 
     Moreover, a tray  1324  is disposed over back surface  1320 . This tray  1324  may be mechanically coupled to external housing  1310  adjacent to edge  1314 . For example, tray  1324  may be mechanically coupled to external housing  1310  using screws. 
     Furthermore, battery cells  212 - 1  and  212 - 2  may be mechanically coupled to an opposite side  1326  of tray  1324  from back surface  1320 . For example, battery cells  212 - 1  and  212 - 2  may be mechanically coupled to tray  1324  by a mechanical coupling mechanism  1328 . In general, mechanical coupling mechanism  1328  may include an adhesive layer. For example, mechanical coupling mechanism  1328  may include two outer layers surrounding an inner layer, and the inner layer may have a lower sheer strength than either of the outer layers. (Thus, mechanical coupling mechanism  1328  may include mechanical coupling mechanism  1014  illustrated in  FIGS. 10-12 .) Using tray  1324 , battery cells  212 - 1  and  212 - 2  may be removed from portable electronic device  1300  without damaging keyboard  1316  (e.g., without damaging back-lighting elements  1322 ). 
     As shown in  FIG. 14 , which presents a block diagram illustrating a top view of a portable electronic device  1300 , tray  1324  may include sidewalls  1330 . These sidewalls may allow tray  1324  to increase a compressive strength of portable electronic device  1300  and/or a bending strength of portable electronic device  1300 . 
     In an exemplary embodiment, external housing  1310  and tray  1324  are made of metal. 
     Referring back to  FIG. 2 , in some embodiments control logic in integrated circuit  216  performs a disabling procedure so that battery-management circuit board  214  (and, thus, power supply  210  or power supply  310  in  FIG. 3 ) cannot be reused after it has been removed from the portable electronic device, which may help ensure safety. This is shown in  FIG. 15 , which presents a block diagram illustrating battery-management circuit board  214 . Battery-management circuit board  214  includes: substrate  1510 , and integrated circuit  216  disposed on substrate  1510 . Moreover, integrated circuit  216  includes: an interface circuit  1512  that receives an instruction code (for example, from motherboard  220  in  FIG. 2 or 3 ); and control logic  1514  that performs a disabling procedure when the instruction code is received. During the disabling procedure, control logic  1514 : provides a discharge signal to battery cells  212  ( FIGS. 2 and 3 ) electrically coupled to battery-management circuit board  214 ; receives confirmation signals from battery cells  212  ( FIGS. 2 and 3 ) that battery cells  212  ( FIGS. 2 and 3 ) are discharged below a threshold; and permanently disables battery-management circuit board  214  so it can no longer charge battery cells  212  ( FIGS. 2 and 3 ). After the disabling procedure, battery-management circuit board  214  (and, thus, power supply  210  or power supply  310  in  FIG. 3 ) can be safely removed from portable electronic device  200  or  300  ( FIG. 3 ). 
     Note that the threshold may be about 5% of capacity of each of battery cells  212  ( FIGS. 2 and 3 ). 
     In some embodiments, prior to permanently disabling battery-management circuit board  214 , control logic  1514  stores a timestamp and a discharge state of battery cells  212  ( FIGS. 2 and 3 ) in a memory  1516  disposed on battery-management circuit board  214 . This stored information may be used in the event of a subsequent safety issue or concern associated with any of battery cells  212  ( FIGS. 2 and 3 ). 
     Moreover, permanently disabling battery-management circuit board  214  may involve a software fuse and/or a hardware fuse, such as fuse  1518 . For example, fuse  1518  may be a thermal fuse. 
     As noted previously, during normal operation control logic  1514  may monitor battery cells  212  ( FIGS. 2 and 3 ), and may regulate charging and discharging of battery cells  212  ( FIGS. 2 and 3 ). 
     Portable electronic device  200  ( FIG. 2 ) or  300  ( FIG. 3 ) may include: one or more program modules or sets of instructions stored in an optional memory subsystem on motherboard  220  in  FIG. 2 or 3  (such as DRAM or another type of volatile or non-volatile computer-readable memory), which may be executed by an optional processing subsystem on motherboard  220  in  FIG. 2 or 3 . Note that the one or more computer programs may constitute a computer-program mechanism. Moreover, instructions in the various modules in the optional memory subsystem may be implemented in: a high-level procedural language, an object-oriented programming language, and/or in an assembly or machine language. Furthermore, the programming language may be compiled or interpreted, e.g., configurable or configured, to be executed by the optional processing subsystem. 
     In some embodiments, functionality in these circuits, components and devices may be implemented in one or more: application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), and/or one or more digital signal processors (DSPs). Moreover, the circuits and components may be implemented using any combination of analog and/or digital circuitry, including: bipolar, PMOS and/or NMOS gates or transistors. Furthermore, signals in these embodiments may include digital signals that have approximately discrete values and/or analog signals that have continuous values. Additionally, components and circuits may be single-ended or differential, and power supplies may be unipolar or bipolar. 
     Portable electronic device  200  ( FIG. 2 ) or  300  ( FIG. 3 ) may include one of a variety of devices that can include a power supply, including: a laptop computer, a media player (such as an MP3 player), an appliance, a subnotebook/netbook, a tablet computer, a smartphone, a cellular telephone, a network appliance, a personal digital assistant (PDA), a toy, a controller, a digital signal processor, a game console, a device controller, a computational engine within an appliance, a consumer-electronic device, a portable computing device, a personal organizer, and/or another electronic device. 
     Additionally, one or more of the components may not be present in  FIGS. 2-15 . In some embodiments, the preceding embodiments include one or more additional components that are not shown in  FIGS. 2-15 . Also, although separate components are shown in  FIGS. 2-15 , in some embodiments some or all of a given component can be integrated into one or more of the other components and/or positions of components can be changed. For example, instead of electrically coupling spring connectors in subset  516  in  FIG. 5  (and a corresponding subset of spring connectors  422  in  FIG. 4 ), the electrical coupling may be implemented in a dedicated subset of electrical connectors  414  and  430  in  FIG. 4  for the monitoring signals. Furthermore, in embodiments in which battery-management circuit board  214  in  FIGS. 2 and 3  is hot-plugged, the monitoring signals may include a clock signal. 
     In the preceding description, we refer to ‘some embodiments.’ Note that ‘some embodiments’ describes a subset of all of the possible embodiments, but does not always specify the same subset of embodiments. 
     We now describe embodiments of methods that can be performed using the preceding embodiments.  FIG. 16  presents a flowchart illustrating a method  1600  for operating a power supply in a portable electronic device. During operation, the power supply provides electrical power from battery cells in separate locations in the power supply to a battery-management circuit board in the power supply (operation  1610 ) that monitors the battery cells and regulates charging and discharging of the battery cells. Note that the battery cells are not enclosed in the common battery-pack housing so that the battery cells are mechanically separate from each other, and the battery-management circuit board is external to the battery cells and is not enclosed in the battery-pack housing. Moreover, the power supply provides the electrical power from the battery-management circuit board to a motherboard in the portable electronic device (operation  1612 ). 
       FIG. 17  presents a flowchart illustrating a method  1700  for operating a power supply in a portable electronic device. During operation, the power supply provides electrical power from battery cells in the power supply to a battery-management circuit board in the power supply that monitors the battery cells and regulates charging and discharging of the battery cells. Note that the battery cells include subsets in which at least some of the battery cells have different capacities. Furthermore, the battery cells in each of the subsets are electrically coupled to the battery-management circuit board so that each of the subsets has a common total capacity (operation  1710 ). 
       FIG. 18  presents a flowchart illustrating a method  1800  for operating a power supply in a portable electronic device. During operation, the power supply provides power signals from a battery-management circuit board in the power supply to a motherboard via first spring connectors on an interposer (operation  1810 ) between the battery-management circuit board and the motherboard. Moreover, the power supply provides monitoring signals from the battery-management circuit board to the motherboard via second spring connectors on the interposer (operation  1812 ), where the first spring connectors have a first vertical height when activated, the second spring connectors have a second vertical height when activated, and the first vertical height is larger than the second vertical height. 
       FIG. 19  presents a flowchart illustrating a method  1900  for removing a battery cell from a portable electronic device. During the method, a sheer force is applied to a mechanical coupling mechanism that mechanically couples the battery cell to an external housing of the portable electronic device using a tab that is mechanically coupled to a side of the battery cell (operation  1910 ). Then, after the battery cell is detached from the external housing, the battery cell is removed from the portable electronic device (operation  1912 ). 
       FIG. 20  presents a flowchart illustrating a method  2000  for removing a battery cell from a portable electronic device. During the method, a mechanical coupling mechanism that mechanically couples the battery cell to an external housing of the portable electronic device is singulated using a detachment mechanism that is embedded in the mechanical coupling mechanism (operation  2010 ). Then, after the battery cell is detached from the external housing, the battery cell is removed from the portable electronic device (operation  2012 ). 
       FIG. 21  presents a flowchart illustrating a method  2100  for disabling a power supply. During operation, a battery-management circuit board in the power supply receives an instruction code (operation  2116 ). In response to the instruction code, the battery-management circuit board performs a disabling procedure (operation  2118 ). This disabling procedure includes the operations of: providing a discharge signal to battery cells (operation  2120 ) in the power supply that are electrically coupled to the battery-management circuit; receiving confirmation signals from the battery cells that the battery cells are discharged below a threshold (operation  2122 ); and permanently disabling the battery-management circuit board (operation  2126 ). 
     In some embodiments, prior to permanently disabling the battery-management circuit board (operation  2126 ), the disabling procedure involves optionally storing a timestamp and a discharge state of the battery cells (operation  2124 ), for example, in a memory disposed on the battery-management circuit board. 
     Note that, during normal operation (operation  2110 ), the control logic performs the operations of: monitoring the battery cells (operation  2112 ); and regulating charging and discharging of the battery cells (operation  2114 ). 
     In some embodiments of the preceding methods, there may be additional or fewer operations. For example, in operation  1910  ( FIG. 19 ) or  2010  ( FIG. 20 ), the battery cell may be mechanically coupled to an arbitrary surface (not just the external housing). Moreover, the order of the operations may be changed, and/or two or more operations may be combined into a single operation. 
     The foregoing description is intended to enable any person skilled in the art to make and use the disclosure, and is provided in the context of a particular application and its requirements. Moreover, the foregoing descriptions of embodiments of the present disclosure have been presented for purposes of illustration and description only. They are not intended to be exhaustive or to limit the present disclosure to the forms disclosed. Accordingly, many modifications and variations will be apparent to practitioners skilled in the art, and the general principles defined herein may be applied to other embodiments and applications without departing from the spirit and scope of the present disclosure. Additionally, the discussion of the preceding embodiments is not intended to limit the present disclosure. Thus, the present disclosure is not intended to be limited to the embodiments shown, but is to be accorded the widest scope consistent with the principles and features disclosed herein.

Metadata:
Filing Date: 20120926
Publication Date: 20170711
Grant Date: 20170711
Priority Date: 20120607
Inventors: HOPKINSON RON A.
DEGNER BRETT W.
MURPHY ROBERT S.
LIGTENBERG CHRISTIAAN A.
CASEBOLT MATTHEW P.
ARNOLD PETER M.
KNOPF ERIC A.
Assignee: APPLE INC
CPC Classifications: [{"code": "H01M10/441", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01M10/482", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01M50/209", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01M10/482", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01M2/1066", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01M10/0525", "inventive": false, "first": false, "tree": "[]"}, {"code": "Y10T29/49117", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01M10/441", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01M50/209", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01M10/482", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01M10/482", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01M50/209", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01M10/441", "inventive": true, "first": true, "tree": "[]"}, {"code": "Y02E60/10", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01M10/441", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01M10/0525", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01M10/0525", "inventive": false, "first": false, "tree": "[]"}, {"code": "Y10T29/49117", "inventive": false, "first": false, "tree": "[]"}, {"code": "Y10T29/49117", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01M10/0525", "inventive": false, "first": false, "tree": "[]"}]
Family ID: 49715133