Abstract:
The present subject matter includes one embodiment of an apparatus, comprising: a battery including a plurality of flat battery layers disposed in a battery case, the battery case having a planar battery surface which has a battery perimeter; and a capacitor including a plurality of flat capacitor layers disposed in a capacitor case, the capacitor case having a planar capacitor surface which has a capacitor perimeter, the capacitor stacked with the battery such that the planar battery surface and the planar capacitor surface are adjacent, with the capacitor perimeter and the battery perimeter substantially coextensive; a hermetically sealed implantable housing having a first shell and a lid mated to the first shell at a first opening, the first opening sized for passage of the battery, the capacitor, and the programmable electronics, wherein the battery and the capacitor are disposed in the hermetically sealed implantable housing.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a continuation of U.S. application Ser. No. 11/117,952, filed Apr. 29, 2005, the specification of which is herein incorporated by reference. 
         [0002]    The following commonly assigned U.S. patents are related to the present application and are incorporated herein by reference in their entirety: “High-Energy Capacitors for Implantable Defibrillators,” U.S. Pat. No. 6,556,863, filed Oct. 2, 1998, issued Apr. 29, 2003; “Flat Capacitor for an Implantable Medical Device,” U.S. Pat. No. 6,699,265, filed Nov. 3, 2000, issued Mar. 2, 2004. Additionally, the present application is related to the following commonly assigned U.S. Patent Publication which is incorporated herein by reference in its entirety: “Method and Apparatus for Single High Voltage Aluminum Capacitor Design,” Ser. No. 60/588,905, filed on Jul. 16, 2004. Further, the present application is related to the following commonly assigned U.S. patent application which is incorporated by reference in its entirety: “Batteries Including a Flat Plate Design,” U.S. patent application Ser. No. 10/360,551 filed Feb. 7, 2003, which claims the benefit under 35 U.S.C 119(e) of U.S. Provisional Application Ser. No. 60/437,537 filed Dec. 31, 2002. 
     
    
     TECHNICAL FIELD 
       [0003]    This disclosure relates generally to batteries and capacitors, and more particularly, to method and apparatus for an implantable pulse generator with a stacked battery and capacitor. 
       BACKGROUND 
       [0004]    There is an ever-increasing interest in making electronic devices physically smaller. Consequently, electrical components become more compact as technologies are improved. However, such advances in technology also bring about additional problems. One such problem involves efficient packaging of components. 
         [0005]    Components such as batteries, capacitors, and various additional electronics are often packaged together in electrical devices. As such, there is a need in the art for improved packaging strategies. Improvement could be realized by an overall increase in the efficiency of component packaging in existing devices. But improved systems must be robust and adaptable to various manufacturing processes. 
       SUMMARY 
       [0006]    The above-mentioned problems and others not expressly discussed herein are addressed by the present subject matter and will be understood by reading and studying this specification. 
         [0007]    One embodiment of the present subject matter includes a method of stacking flat battery layers into a battery stack; positioning the battery stack in a battery case, the planar battery surface having a battery perimeter; stacking flat capacitor layers into a capacitor stack; positioning the capacitor stack in a capacitor case, the planar capacitor surface having a capacitor perimeter; disposing the flat battery case and the flat electrolytic capacitor case in stacked alignment in a housing for implantation such that the battery perimeter and the capacitor perimeter are substantially coextensive; and hermetically sealing the housing. 
         [0008]    Additionally, one embodiment of the present subject matter includes a battery having a plurality of flat battery layers disposed in a battery case, the battery case having a planar battery surface which has a battery perimeter; and a capacitor including a plurality of flat capacitor layers disposed in a capacitor case, the capacitor case having a planar capacitor surface which has a capacitor perimeter, the capacitor stacked with the battery such that the planar battery surface and the planar capacitor surface are adjacent, with the capacitor perimeter and the battery perimeter substantially coextensive; and a hermetically sealed implantable housing having a first shell and a lid mated to the first shell at a first opening, the first opening sized for passage of the battery and the capacitor, wherein the battery and the capacitor are disposed in the hermetically sealed implantable housing. 
         [0009]    One embodiment of the present subject matter includes an apparatus having a hermetically sealed implantable device housing having a lid mated to an opening; programmable pulse generation electronics disposed in the hermetically sealed implantable device housing, the programmable pulse generation electronics sized for passage through the opening; battery means for powering the programmable pulse generation electronics, the battery means sized for passage through the opening; and capacitor means electrically interconnected to the battery means, the capacitor means for powering the programmable pulse generation electronics and sized for passage through the opening. 
         [0010]    This Summary is an overview of some of the teachings of the present application and not intended to be an exclusive or exhaustive treatment of the present subject matter. Further details about the present subject matter are found in the detailed description and appended claims. Other aspects will be apparent to persons skilled in the art upon reading and understanding the following detailed description and viewing the drawings that form a part thereof, each of which are not to be taken in a limiting sense. The scope of the present invention is defined by the appended claims and their legal equivalents. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]      FIG. 1A  is a side view of a power source, according to one embodiment of the present subject matter. 
           [0012]      FIG. 1B  illustrates a partial cross section of a device housing, a battery, and a capacitor, according to one embodiment of the present subject matter. 
           [0013]      FIG. 2  is a perspective view of a capacitor, according to one embodiment of the present subject matter. 
           [0014]      FIG. 3  is a perspective view of a battery, according to one embodiment of the present subject matter. 
           [0015]      FIG. 4  is a perspective view of a battery and a capacitor, according to one embodiment of the present subject matter. 
           [0016]      FIG. 5  is a method for constructing a battery and capacitor power source, according to one embodiment of the present subject matter. 
       
    
    
     DETAILED DESCRIPTION 
       [0017]    The following detailed description of the present subject matter refers to subject matter in the accompanying drawings which show, by way of illustration, specific aspects and embodiments in which the present subject matter may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the present subject matter. References to “an”, “one”, or “various” embodiments in this disclosure are not necessarily to the same embodiment, and such references contemplate more than one embodiment. The following detailed description is demonstrative and not to be taken in a limiting sense. The scope of the present subject matter is defined by the appended claims, along with the full scope of legal equivalents to which such claims are entitled. 
         [0018]    Implantable medical devices are now in wide use for treating a variety of diseases. Cardiac rhythm management devices, as well as other types of implantable medical devices, are powered by a battery and a capacitor contained within the housing of the device. The size and shape of a battery which supplies sufficient power to operate the device is one factor which affects how small and physiologically shaped the housing of the device can be made. This is true for the capacitor as well. The present disclosure relates to a battery and capacitor and method for their construction, each suitable for use in an electronic device. Various embodiments are adapted for use in an implantable medical device. Overall, the present subject matter affords designers more freedom in packaging electronic device components into a housing. 
         [0019]      FIG. 1A  is a side view of a power source  100 , according to one embodiment of the present subject matter. In various embodiments, an example battery  102  includes a contour  116 , which allows for positioning the battery  102  in various devices. For example, in various embodiments, battery  102  is shaped for placement in device adapted for chronic implantation. Additionally, in various embodiments, the battery  102  includes a feedthrough port  108 , which is adapted for passage of one or more conductors. In various embodiments, the conductors at the feedthrough port  108  are connected to the battery anode. The battery additionally includes a feedthrough port  110  which, in various embodiments, is connected to the battery cathode. In some embodiments, a single feedthrough port is used instead of two feedthrough ports. Other embodiments include one or more feedthrough ports and a backfill port. 
         [0020]    In various embodiments, the example capacitor  104  includes a contour  118 , which allows for positioning the capacitor  104  in various devices. For example, in various embodiments, capacitor  104  is shaped for placement in a device adapted for chronic implantation. Additionally, in various embodiments, the capacitor  104  includes a feedthrough port  112 , which is adapted for passage of one or more conductors. In various embodiments, the conductors at the feedthrough port  112  comprise a portion of the anode of the capacitor. The capacitor additionally includes a feedthrough port  114  which, in various embodiments, is connected to the battery cathode. In some embodiments, a single feedthrough port is used instead of two feedthrough ports. Other embodiments include one or more feedthrough ports and a backfill port. 
         [0021]    In various embodiments, a device housing into which a battery and capacitor may be disposed has an interior. In some of these embodiments, the device interior has a first major interior face and a second major interior face. Battery and capacitor combinations can be shaped to mate to these faces. For example, in one embodiment, a battery face  120  is adapted for abutting an interior face of a housing. In some embodiments, the housing and the battery face  120  are separated from a housing by an insulator. The capacitor includes a face  122  which also is adapted for abutting an interior surface of a housing. Sidewall  402  and sidewall  404  are adapted for placement adjacent additional device components, in various embodiments. 
         [0022]    Various embodiments maintain a continuous surface from sidewall  402  to sidewall  404 . In various embodiments, the seam  106  defined by the adjacent battery  102  and capacitor  104  extends along a continuous surface. Thus, in various embodiments, the combined capacitor and battery are adapted for space efficient placement in a housing. In various embodiments, the housing is only marginally larger than the combined capacitor and battery so that the housing may accommodate those components. As such, various embodiments enable packaging additional devices in the housing adjacent the battery capacitor combination. 
         [0023]    Battery  102  has a thickness T B , in various embodiments. In various embodiments, the thickness is measured orthogonally, extending between interface  106  and surface  120 . Additionally, capacitor  104  has a thickness T C , in various embodiments. The thickness is measured orthogonally, extending between interface  106  and surface  122 , in various embodiments. In various embodiments, the thicknesses T B  and T C  are selectable to fill the volume of a device housing. For example, in one embodiment, the present subject matter creates an index of a plurality of flat capacitors, the index created by measuring the thickness T C  of each flat capacitor and storing that thickness in a first index. Additionally, in various embodiments, the present subject matter creates an index of a plurality of flat batteries, the index created by measuring the thickness T B  of each flat battery and storing that thickness in a second index. The present subject matter than selects a battery and a capacitor having respective thicknesses T B , T C  selected to fill the volume of the targeted device housing. 
         [0024]      FIG. 1B  illustrates a partial cross section of a device housing  150 , a battery  102 , and a capacitor  104 , according to one embodiment of the present subject matter. In various embodiments, distance D extends between a first interior surface  152  for abutting a battery face  120 , and a second interior surface  154  adapted for abutting surface  122 . In various embodiments, the present subject matter selects a capacitor from a first index, and a battery from a second index, such that the combined thickness of the battery and the capacitor substantially match the thickness D. Additionally, in various embodiments, the selection of battery thickness and capacitor thickness is made in light of the thickness of adhesive layer and/or insulative layers disposed between the battery and the capacitor, and between these respective subcomponents and the device housing. In varying embodiments, the ratio between capacitor thickness and battery thickness is from about 7:1 to about 1.5:1. In additional embodiment, the ratio between the capacitor thickness and the battery thickness is from about 6:1 to about 2:1. Other ratios are possible without departing from the scope of the present subject matter. 
         [0025]    In various embodiments, indexing of battery thickness, capacitor thickness, battery perimeter, capacitor perimeter, and other power source parameters is performed using a programmable computer. The present subject matter is not limited to indexes managed by programmable computers, however, as other indexing systems are within the scope of the present subject matter. 
         [0026]      FIG. 2  is a perspective view of a capacitor, according to one embodiment of the present subject matter. Substantially flat electrolytic capacitors, in various examples, include a plurality of capacitor layers stacked together. In various embodiments, these stacks of capacitors are assembled into a capacitor case. Various cases are conductive or nonconductive. Some cases include feedthroughs through which conductors pass. The present subject matter includes, but is not limited to, embodiments disclosed on or around pages 12-37, 39, 41-140 of the following related and commonly assigned Provisional U.S. patent application “Method and Apparatus for Single High Voltage Aluminum Capacitor Design,” Ser. No. 60/588,905, filed on Jul. 16, 2004, incorporated herein by reference. 
         [0027]    In various embodiments, the present subject matter includes a flat electrolytic capacitor  104  with a planar capacitor surface  202 . In various embodiments, the planar capacitor surface includes a capacitor perimeter. In various embodiments, the capacitor stack is adapted to deliver between 7.0 Joules/cubic centimeter and 8.5 Joules/cubic centimeter. Some embodiments are adapted to deliver about 7.7 Joules/cubic centimeter. In some embodiments, the anode has a capacitance of between approximately 0.70 and 0.85 microfarads per square centimeter when charged at approximately 550 volts. In various embodiments, these ranges are available at a voltage of between about 410 volts to about 610 volts. 
         [0028]    However, in some embodiments, the stack is disposed in a case, and linked with other components, a state which affects energy density in some embodiments. For example, in one packaged embodiment, including a case and terminals, the energy density available ranges from about 5.3 Joules per cubic centimeter of capacitor stack volume to about 6.3 Joules per cubic centimeter of capacitor stack volume. Some embodiments are adapted to deliver about 5.8 Joules. In various embodiments, these ranges are available at a voltage of between about 410 volts to about 610 volts. 
         [0029]    Although these ranges embody one example possible within the scope of the subject matter, the subject matter is not so limited, and other capacitors without departing from the scope of the present subject matter. 
         [0030]      FIG. 3  is a perspective view of a battery, according to one embodiment of the present subject matter. In various embodiments, the battery  102  of the present subject matter is substantially flat. Substantially flat batteries, in various examples, include a plurality of battery electrodes stacked together, and further assembled into a battery case. Various battery cases are conductive or nonconductive. Some battery cases include feedthroughs. In various embodiments, the battery cases include a planar battery surface  302 . The present subject matter includes, but is not limited to, embodiments disclosed at paragraphs 0095-0110, 0136-0196, 0206-0258 of the following related and commonly assigned U.S. patent application, “Batteries Including a Flat Plate Design,” U.S. patent application Ser. No. 10/360,551, filed on Feb. 7, 2003, incorporated herein by reference. 
         [0031]      FIG. 4  is a perspective view of a battery and a capacitor, according to one embodiment of the present subject matter. In various embodiments, the present subject matter includes a power source  100  which has a battery  102  and a capacitor  104  mated at an interface  106 , at which a planar battery surface and a planar capacitor surface are substantially coextensive. As a result of alignment, various embodiments demonstrate an overall envelope which is substantially continuous. Additionally, in various embodiments, the battery  102  includes a feedthrough ports  108 ,  110 . Capacitor  104  includes feedthrough ports  112 ,  114 , in various embodiments. 
         [0032]    Various capacitor embodiments include a capacitor sidewall  402 , and various battery embodiments include a battery sidewall  404 . Various embodiments additionally include a battery face  120 . A capacitor face is not visible in the illustration due to the orientation of the figure. In various examples, each of these respective case features is planar. When placed adjacent to one another, various embodiments include features which form a substantially planar overall sidewall which is the sum of each of the individual surfaces. In various embodiments, the overall surface is continuous. For example, sidewalls  402 ,  404  form a continuous surface. A continuous surface may have a linear shape, or a curvilinear shape. Embodiments having a continuous overall sidewall are within the scope of the present subject matter, however, additional embodiments are possible without departing from the scope of the scope of the present subject matter. 
         [0033]      FIG. 5  is a method for constructing a battery and capacitor power source, according to one embodiment of the present subject matter. In one embodiment of the present subject matter, the process includes establishing form factor and power capacity requirements for a power source to be used in an implantable medical device  502 . The embodiment includes constructing a flat battery by stacking flat battery layers into a battery stack and positioning the stack in a battery case with a planar interface and a battery perimeter and battery thickness  504 . The embodiment further includes constructing a flat electrolytic capacitor by stacking flat capacitor layers into a capacitor stack and positioning the stack in a capacitor case with a planar interface and a capacitor perimeter and capacitor thickness  506 . The embodiment additionally includes stacking the flat battery and the flat electrolytic capacitor such that the battery perimeter and the capacitor perimeter are substantially coextensive  510 . This embodiment is illustrative of the present subject matter, but it should be noted that other combinations of steps, and additional steps, also lie within the scope of the present subject matter. 
         [0034]    For example, in some embodiments, a battery thickness, battery perimeter, capacitor thickness and capacitor perimeter are selected based on form factor and power capacity requirements for an implantable medical device  508 . Additionally, various method embodiments include measuring a ratio between battery thickness and capacitor thickness, and using this ratio in selecting a battery and capacitor. A ratio is be established by known power requirements, in various embodiments. Another example combines size requirements with power requirements in selecting a ratio. The ratio can be stored and used by a design process or manufacturing process to discern the mechanical and electrical composition of a needed power source, in various embodiments. 
         [0035]    In various embodiments, the present subject matter includes delivering from the flat battery and the flat electrolytic capacitor from about 1.25 Joules per Amp hour of battery capacity to about 50 Joules per amp hour of battery capacity. In some of these embodiments, the flat battery has a battery capacity density of from about 0.23 amp hours per cubic centimeter of flat battery to about 0.25 amp hours per cubic centimeter of flat battery. Battery capacity density is measured by dividing the amp-hour rating of the battery by the battery volume, in various embodiments. The present subject matter includes, but is not limited to, embodiments disclosed at paragraphs 0095-0110, 0136-0196, 0206-0258 of the following related and commonly assigned U.S. Patent Publication, “Batteries Including a Flat Plate Design,” U.S. Patent Publication No. 2004/0127952, filed on Feb. 7, 2003, incorporated herein by reference. 
         [0036]    In additional embodiments, the flat electrolytic capacitor includes an energy density of from about 4.65 joules per cubic centimeter of flat electrolytic capacitor to 6.5 joules per cubic centimeter of flat electrolytic capacitor. The present subject matter includes, but is not limited to, embodiments disclosed on or around pages 12-37, 39, 41-140 of the following related and commonly assigned Provisional U.S. patent application “Method and Apparatus for Single High Voltage Aluminum Capacitor Design,” Ser. No. 60/588,905, filed on Jul. 16, 2004, incorporated herein by reference. 
         [0037]    Various methods of the present subject matter benefit from selecting capacitor stack layers and battery stack layers which are substantially parallel to their coextensive case interfaces. By constructing the power source as such, various benefits are possible. For example, in one embodiment, a single two-axis machine can position capacitor layers in a stack, position the capacitor stack in a capacitor case, position battery layers in a stack, and position the battery stack in a battery case. In one embodiment, the single two-axis machine is a pick-and-place machine. This combination is provided for illustration, but other combinations of these steps are possible, and additional steps are also within the scope of the present subject matter. 
         [0038]    Although specific embodiments have been illustrated and described herein, it will be appreciated by those of ordinary skill in the art that any arrangement which is calculated to achieve the same purpose may be substituted for the specific embodiment shown. This application is intended to cover adaptations or variations of the present subject matter. It is to be understood that the above description is intended to be illustrative, and not restrictive. Combinations of the above embodiments, and various embodiments, will be apparent to those of skill in the art upon reviewing the above description. The scope of the present subject matter should be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled.