Patent Abstract:
Structures for serially connecting at least two capacitors together are described. Serially connecting capacitors together provides device manufactures, such as those selling implantable medical devices, with broad flexibility in terms of both how many capacitors are incorporated in the device and what configuration the capacitor assembly will assume.

Full Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     The present application claims priority based upon provisional application Ser. Nos. 60/540,263 and 60/540,264, both filed Jan. 28, 2004.  
       BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     The present invention generally relates to a capacitor and, more particularly, to at least two side-by-side capacitors connected in series. This is done using various interconnect structures connecting between the negative polarity pin/casing of one capacitor to the positive polarity lead of another. The present interconnects are of a relatively low profile having a conductive member insulted from the capacitor casings and to which the positive pin and negative lead are welded. A polymeric material disposed there between otherwise insulates the side-by-side capacitors from each other.  
         [0004]     2. Prior Art  
         [0005]     FIGS.  1  to  4  show a conventional design for a series connected capacitor assembly  10  comprising a first capacitor  12  and a side-by-side second capacitor  14 . The first capacitor  12  comprises an anode of an anode active material  16  and a cathode of a cathode active material  18  ( FIG. 4 ) housed inside a hermetically sealed casing  20 . The capacitor electrodes are operatively associated with each other by an electrolyte (not shown) contained inside the casing, as will be described in detail hereinafter. It should be pointed out that the capacitors  12 ,  14  can be of either an electrochemical type wherein both the anode and the cathode electrodes are provided by conductive substrates having a capacitive material contacted thereto, or an electrolyte type wherein the cathode electrode is provided by a conductive substrate having capacitive properties. The illustrated capacitors are preferably of the latter type, however, that should not be construed as limiting.  
         [0006]     As particularly shown in  FIGS. 2 and 3 , casing  20  is of a metal material comprising mating first and second clamshells or mating casing portions  22  and  24 . Casing portion  22  comprises a surrounding sidewall  26  extending to a face wall  28 . Similarly, casing portion  24  comprises a surrounding sidewall  30  extending to a face wall  32 . The sidewall  26  of the first casing portion  22  is sized to fit inside the periphery of the second sidewall  30  in a closely spaced relationship. This means that the first face wall  28  is somewhat smaller in planar area than the second face wall  32  of casing portion  24 . Also, the height of the second surrounding sidewall  30  of casing portion  24  is less than the height of the first surrounding sidewall  26 . The surrounding sidewall  26  has an inwardly angled lead-in portion  34  that facilitates mating the casing portions  22 ,  24  to each other.  
         [0007]     With the first and second casing portions  22 ,  24  mated to each other, the distal end of the second surrounding sidewall  30  contacts the first surrounding sidewall  26  a short distance toward the face  28  from the bend forming the lead-in portion  34 . The casing portions  22 ,  24  are hermetically sealed to each other by welding the sidewalls  26 ,  30  together at this contact location. The weld is provided by any conventional means; however, a preferred method is by laser welding.  
         [0008]     The anode active material  16  is typically of a metal selected from the group consisting of tantalum, aluminum, titanium, niobium, zirconium, hafnium, tungsten, molybdenum, vanadium, silicon, germanium, and mixtures thereof in the form of a pellet. As is well known by those skilled in the art, the anode metal in powdered form, for example tantalum powder, is compressed into a pellet having an anode wire  36  embedded therein and extending there from, and sintered under a vacuum at high temperatures. The porous body is then anodized in a suitable electrolyte to fill its pores with the electrolyte and form a continuous dielectric oxide film on the sintered body. The assembly is then reformed to a desired voltage to produce an oxide layer over the sintered body and anode wire. The anode can also be of an etched aluminum or titanium foil.  
         [0009]     The cathode electrode is spaced from the anode electrode housed inside the casing and comprises the cathode active material  18 . The cathode active material has a thickness of about a few hundred Angstroms to about 0.1 millimeters directly coated on the inner surface of the face walls  28 ,  32  (FIGS.  2  to  4 ) or, it is coated on a conductive substrate (not shown) in electrical contact with the inner surface of the face walls. In that respect, the face walls  28 ,  32  may be of an anodized-etched conductive material, have a sintered active material with or without oxide contacted thereto, contacted with a double layer capacitive material, for example a finely divided carbonaceous material such as graphite or carbon or platinum black, a redox, pseudocapacitive or an under potential material, or be an electroactive conducting polymer such as polyaniline, polypyrol, polythiophene, and polyacetylene, and mixtures thereof.  
         [0010]     The redox or cathode active material  18  includes an oxide of a first metal, a nitride of the first metal, a carbonnitride of the first metal, and/or a carbide of the first metal, the oxide, nitride, carbonnitride and carbide of the first metal having pseudocapacitive properties. The first metal is preferably selected from the group consisting of ruthenium, cobalt, manganese, molybdenum, tungsten, tantalum, iron, niobium, iridium, titanium, zirconium, hafnium, rhodium, vanadium, osmium, palladium, platinum, nickel, and lead, an oxide of the former being preferred.  
         [0011]     The cathode active material  18  may also include a second or more metals. The second metal is in the form of an oxide, a nitride, a carbonnitride or carbide, and is not essential to the proper functioning of the capacitor electrode. The second metal is different than the first metal and is selected from one or more of the group consisting of tantalum, titanium, nickel, iridium, platinum, palladium, gold, silver, cobalt, molybdenum, ruthenium, manganese, tungsten, iron, zirconium, hafnium, rhodium, vanadium, osmium, and niobium.  
         [0012]     The mating casing portions  22 ,  24 , and the electrically connected conductive substrate if it is provided, are preferably selected from the group consisting of tantalum, titanium, nickel, molybdenum, niobium, cobalt, stainless steel, tungsten, platinum, palladium, gold, silver, copper, chromium, vanadium, aluminum, zirconium, hafnium, zinc, iron, and mixtures and alloys thereof. Preferably, the face and sidewalls of the casing portions have a thickness of about 0.001 to about 2 millimeters.  
         [0013]     The exemplary electrolytic type capacitor shown in FIGS.  1  to  4  has the cathode active material  18  preferably coating the face walls  28 ,  32  spaced from the respective sidewalls  26 ,  30 . Such a coating is accomplished by providing the conductive face walls  28 ,  32  with a masking material in a known manner so that only an intended area of the face walls is contacted with active material. The masking material is removed from the face walls prior to capacitor fabrication. Preferably, the cathode active material  18  is substantially aligned in a face-to-face relationship with the major faces of the anode active material  16 . A preferred coating process is in the form of an ultrasonically generated aerosol as described in U.S. Pat. Nos. 5,894,403; 5,920,455; 6,224,985; and 6,468,605, all to Shah et al. These patents are assigned to the assignee of the present invention and incorporated herein by reference.  
         [0014]     A separator (not shown) of electrically insulative material is provided between the anode active material  16  and the cathode active material  18  to prevent an internal electrical short circuit between them. The separator material also is chemically unreactive with the anode and cathode active materials and both chemically unreactive with and insoluble in the electrolyte. In addition, the separator material has a degree of porosity sufficient to allow flow therethrough of the electrolyte during the electrochemical reaction of the capacitor  12 . Illustrative separator materials include woven and non-woven fabrics of polyolefinic fibers including polypropylene and polyethylene or fluoropolymeric fibers including polyvinylidene fluoride, polyethylenetetrafluoroethylene, and polyethylenechlorotrifluoroethylene laminated or superposed with a polyolefinic or fluoropolymeric microporous film, non-woven glass, glass fiber materials and ceramic materials. Suitable microporous films include a polyethylene membrane commercially available under the designation SOLUPOR® (DMS Solutech), a polytetrafluoroethylene membrane commercially available under the designation ZITEX® (Chemplast Inc.), a polypropylene membrane commercially available under the designation CELGARD® (Celanese Plastic Company, Inc.), and a membrane commercially available under the designation DEXIGLAS® (C. H. Dexter, Div., Dexter Corp.). Cellulose based separators typically used in capacitors are also contemplated. Depending on the electrolyte used, the separator can be treated to improve its wettability, as is well known by those skilled in the art.  
         [0015]     A suitable electrolyte for the capacitors  12 ,  14  is described in U.S. Pat. No. 6,219,222 to Shah et al., which includes a mixed solvent of water and ethylene glycol having an ammonium salt dissolved therein. Other electrolytes for the present capacitors are described in U.S. Pat. No. 6,687,117 to Liu et al. and U.S. Pub. No. 2003/0090857. The electrolyte of the former patent comprises de-ionized water, an organic solvent, isobutyric acid and a concentrated ammonium salt while the latter publication relates to an electrolyte having water, a water-soluble inorganic or organic acid or salt, and a water-soluble nitro-aromatic compound. These patents and publication are assigned to the assignee of the present invention and incorporated herein by reference. The electrolyte is provided inside the hermetically sealed casing through a fill opening closed by a hermetic closure  38  ( FIG. 1 ), as is well known by those skilled in the art.  
         [0016]     The casing  20 , including the portions  22 ,  24 , being of a conductive metal serves as one terminal for making electrical connection between the capacitor and its load. A pin  40  ( FIG. 2 ) is welded to the sidewall  26  to provide the negative terminal for the first capacitor  12 . Pin  40  also provides the negative terminal for the side-by-side capacitor assembly  10 , as will be described in detail hereinafter. The other electrical terminal or contact for the first capacitor  12  comprises the anode wire  36  extending from the anode active material  16  and connected to the anode lead  42  extending through the first surrounding sidewall  26 .  
         [0017]     As shown in  FIGS. 2 and 3 , the anode lead  42  is electrically insulated from the metal casing  20  by an insulator glass-to-metal feedthrough  46 . The glass-to-metal feedthrough  46  comprises a ferrule  48  defining an internal cylindrical through bore or passage  50  of constant inside diameter. Outwardly facing annular steps  52 A and  52 B are provided at the respective upper and lower ferrule ends. The upper step  52 A is of an outer diameter sized to fit in a closely spaced relationship in an annular opening  54  in the first casing sidewall  26  with the remaining body of the ferrule butted against the inner surface of the sidewall. The ferrule  48  is secured therein by welding, and the like.  
         [0018]     As shown in  FIG. 2 , the anode active material  16  has a notch  56  that provides clearance for the glass-to-metal feedthrough  46 . The anode wire  36  embedded in the anode active material  16  extends outwardly from the notch  56 . A distal end  36 A is bent into a position generally parallel to the longitudinal axis of ferrule  48 . A proximal end  42 A of the anode lead  42  is bent into a J-hook shape to align parallel with the distal end  36 A of the anode wire  36 . The distal end  36 A of the anode wire is then welded to the proximal end  42 A of the anode lead to electrically connect the anode to the lead  42 .  
         [0019]     An insulative glass  58  provides a hermetic seal between the inside of the ferrule  48  and the anode lead  42 . The glass is, for example, ELAN® type  88  or MANSOL™ type  88 . The anode lead  42  preferably comprises the same material as the anode active material  16 . In that manner, the portion of the anode lead  42  extending outside the capacitor  12  for connection to a load is hermetically sealed from the interior of the capacitor and insulated from the mating casing portions  22 ,  24  serving as the terminal for the cathode.  
         [0020]     The second capacitor  14  illustrated in drawing FIGS.  1  to  4  is similar to the first capacitor  12  in terms of its physical structure as well as its chemistry. As previously discussed, however, the capacitors  12 ,  14  need not be chemically similar. For example, the first capacitor  12  can be of an electrolytic type while the second capacitor  14  can be of the electrochemical type. Preferably, the capacitors  12 ,  14  are both of the electrolytic type.  
         [0021]     The second capacitor  14  comprises an anode active material  60  and a cathode active material  62  ( FIG. 3 ) housed inside a hermetically sealed casing  64  and operatively associated with each other by an electrolyte (not shown). Casing  64  is similar to casing  20  of capacitor  12  and comprises mating third and fourth portions  66  and  68  ( FIG. 1 ). Casing portion  66  comprises a surrounding sidewall  70  extending to a face wall  72 . Similarly, casing portion  68  comprises a surrounding sidewall  74  extending to a face wall  76 . The sidewall  70  of the third casing portion  66  is sized to fit inside the periphery of the fourth sidewall  74  in a closely spaced relationship. The height of the fourth surrounding sidewall  74  is less than that of the third surrounding sidewall  70  and its inwardly angled lead-in portion  78 . Laser welding the contacting sidewalls  70 ,  74  together hermetically seals the third and fourth mated casing portions  66 ,  68  to each other.  
         [0022]     The cathode active material  62  is supported on the inner surfaces of the face walls  72 ,  76  opposite the major faces of the anode active material  60 . In that manner, the casing  64 , being of a conductive metal, serves as one terminal for making electrical connection between the capacitor  14  and its load.  
         [0023]     The other electrical terminal or contact is provided by a conductor or lead  80  extending from within the capacitor  14  connected to the anode active material  60  and through the third surrounding sidewall  70 . The anode active material  60  is similar in construction to the anode of capacitor  12  and includes a notch that provides clearance for a glass-to-metal feedthrough  82 . An anode wire  84  embedded in the anode active material  60  extends outwardly from the notch to a distal end welded to the proximal end of the anode lead  80  to electrically connect the anode to the lead.  
         [0024]     The glass-to-metal feedthrough  82  electrically insulates the anode lead  80  from the metal casing  64  and comprises a ferrule  86  provided with an annular step of reduced diameter fitted in a closely spaced relationship in an annular opening in the first casing sidewall  70 . The remaining ferrule body is butted against the inner surface of the sidewall with the ferrule  86  being secured therein by welding. An insulative glass  88  hermetically seals between the cylindrical inner surface of the ferrule  86  and the anode lead  80 .  
         [0025]     A separator (not shown) of electrically insulative and ionically conductive material segregates the anode active material  60  from the cathode active material  62 . The electrolyte is provided inside the hermetically sealed casing  64  through a fill opening closed by a hermetic closure  90 .  
         [0026]     The thusly constructed first and second capacitors  12 ,  14  are then positioned back-to-back or side-by-side. In this configuration, the face wall  32  of the casing portion  24  of the first capacitor  12  is aligned with and proximate to the face wall  76  of the casing portion  68  of the second capacitor  14 . An adhesive  94  ( FIG. 3 ), for example, a double-sided polyimide tape, secures the capacitors  12 ,  14  together without the respective casing portions  24 ,  68  being electrically shorted to each other. A suitable tape for this purpose is commercially available from E. I. Du Pont De Nemours and Company Corporation under the trademark KAPTON®. If desired, the capacitors  12 ,  14  are provided with a paralyene coating by a vacuum deposition process about their entire outer surface prior to being aligned in the side-by-side orientation.  
         [0027]     The capacitors  12 ,  14  are then electrically connected in series. The prior art design used with the capacitors  12 ,  14  comprises a connecting tab  96  having a foot portion  96 A secured to the surrounding sidewall  70  of casing portion  68 , such as by welding, adjacent to the anode lead  42  for the first capacitor  12 . An arm portion  96 B of the tab is butted to the distal end of the anode lead  42 . A weld (not shown) then finishes the connection of the tab  96  to the anode lead  42 . This results in the positive polarity anode lead  42  of the first capacitor  12  being connected to the negative polarity casing  64  of the second capacitor  14 . The series connected side-by-side capacitors  12 ,  14  are then connectable to a load (not shown). Connecting the negative polarity terminal pin  40  of the first capacitor  12  and the polarity terminal lead  80  of the second capacitor  14  does this.  
         [0028]     While the prior art design works well, there are improvements that can be made to it. For one, the connection between the anode lead  42  and tab  96  is a “blind” butt weld that demonstrates very poor manufacturing yields. The lead  42  under the tab  96  is typically about 0.0013 to 0.0014 inches in diameter. The spot size for the laser welder is about 0.018 inches in diameter. This means that the laser needs to be aligned perfectly with the lead  42  to effect a robust connection. If not, the laser will blow through the tab  96 , creating scrap. Welding the foot portion  96 A of the tab  96  to the sidewall  70  of casing portion  68  and the arm portion  96 B to the lead  42  are relatively slow processes that utilize expensive tooling to position the tab and then bend it into contact with the sleeve. Finally, the tab  96  can create a sharp edge and the butt-welded tab  96  and lead  42  interconnect takes up a relatively large amount of real estate in both the vertical direction off of the capacitors  12 ,  14  as well as laterally on the capacitor. The prior art connecting tab  96  and anode lead  42  design is the subject of U.S. Patent Application Pub. No. 2004/0120099. This application is assigned to the assignee of the present invention and incorporated herein by reference.  
       SUMMARY OF THE INVENTION  
       [0029]     The current trend in medicine is to make cardiac defibrillators, and other implantable medical devices such as cardiac pacemakers, neurostimulators, and drug pumps, as small and lightweight as possible without compromising power. This, in turn, means that capacitors contained in these devices must be readily adaptable in how they are connected to each other as well as to the battery and the device circuitry. In that light, the present invention relates to structures for serially connecting at least two capacitors together to provide the device manufacture with broad flexibility in terms of both how many capacitors are incorporated in the device and what configuration the capacitor assembly will assume.  
         [0030]     These and other aspects of the present invention will become more apparent to those skilled in the art by reference to the following description and to the appended drawings. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0031]      FIG. 1  is a perspective view looking at the right edges of two side-by-side capacitors  12 ,  14  connected in series according to the prior art.  
         [0032]      FIG. 2  is a cross-sectional view taken along line  2 - 2  of  FIG. 1 .  
         [0033]      FIG. 3  is an enlarged view of the indicated area of  FIG. 2 .  
         [0034]      FIG. 4  is a cross-sectional view taken along line  4 - 4  of  FIG. 2 .  
         [0035]      FIG. 5  is a perspective view of the side-by-side capacitors  12 ,  14  of FIGS.  1  to  4  connected in series with an interconnect  100  according to the present invention.  
         [0036]      FIG. 6  is an exploded view of the interconnect  100  shown in  FIG. 5  including a platform  102  and a conductive bar  114 .  
         [0037]      FIG. 7  is a perspective view of the assembled interconnect  100  shown in  FIG. 6 .  
         [0038]      FIG. 8  is a cross-sectional view along line  8 - 8  of  FIG. 7 .  
         [0039]      FIG. 9  is a partial perspective view of the interconnect  100  being moved onto the respective terminals  42  and  128  for the capacitors  12 ,  14 .  
         [0040]      FIG. 10  is a partial perspective view of the interconnect  100  connecting the capacitors  12 ,  14  in  FIG. 9  in series.  
         [0041]      FIG. 11  is a partial cross-sectional view along line  11 - 11  of  FIG. 10 .  
         [0042]      FIG. 12  is an exploded view of another embodiment of an interconnect  150  including a platform  152  and a conductive bar  114 .  
         [0043]      FIG. 13  is a perspective view of the assembled interconnect  150  shown in  FIG. 12 .  
         [0044]      FIG. 14  is a partial cross-sectional view of the interconnect  150  connecting capacitors  12 ,  14  in series.  
         [0045]      FIG. 15  is a cross-sectional view showing two of the interconnects  150  connecting three capacitors  12 ,  14  and  170  in series.  
         [0046]      FIG. 16  is an exploded view of another embodiment of an interconnect  200  including a platform  202  and a conductive bar  220 .  
         [0047]      FIG. 17  is a bottom perspective view of the platform  202  for the interconnect  200  shown in  FIG. 16 .  
         [0048]      FIG. 18  is a partial perspective view of the interconnect  200  connecting the capacitors  12 ,  14  in series.  
         [0049]      FIG. 18A  is a perspective view of a modified platform  202 A provided with a cutout  214 A.  
         [0050]      FIG. 18B  is a perspective view of the conductive bar  220  nested in the platform  202 A shown in  FIG. 18A  to expose a edge  220 A of the bar for wire bond connection to the series capacitors  12 ,  14 .  
         [0051]      FIG. 19  is a bottom perspective view of another embodiment of an interconnect  250 .  
         [0052]      FIG. 20  is a partial perspective view of the interconnect  250  being moved onto the respective terminals  42  and  128  for the capacitors  12 ,  14 .  
         [0053]      FIG. 21  is a partial top plan view showing the interconnect  250  of  FIGS. 19 and 20  being deformed into locking contact with the terminals  42  and  128 .  
         [0054]      FIG. 22  is a cross-sectional view along lines  22 - 22  of  FIG. 21 .  
         [0055]      FIG. 23  is a partial perspective view of another embodiment of an interconnect  300  being moved onto the terminals  42  and  128  for the capacitors  12 ,  14 .  
         [0056]      FIG. 24  is a partial perspective view of the interconnect  300  of  FIG. 22  being welded to the terminals  42  and  128 .  
         [0057]      FIG. 25  is a partial cross-sectional view along lines  25 - 25  of  FIG. 24 .  
         [0058]      FIG. 26  is a partial perspective view of another embodiment of an interconnect  350  showing distal portions  42 A and  128 A of the respective lead and conductive pin provided in a side-by-side lap joint relationship and being welded together to connect the capacitors  12 ,  14  in series.  
         [0059]      FIG. 27  is a partial perspective view of another embodiment of an interconnect  400  for connecting capacitors  12 ,  14  in series. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0060]     FIGS.  5  to  11  illustrate a first embodiment of a capacitor interconnect  100  according to the present invention. This interconnect is an improvement over the tab  96  and lead  42  interconnect structure described in FIGS.  1  to  4 . In all other respects, the capacitors  12 ,  14  of this and the other present invention embodiments are the same as those described with respect to the prior art, and like structural features and designs will be given the same numerical designations.  
         [0061]     The capacitor interconnect  100  comprises a platform  102  of an insulative thermoplastic or ceramic material having a generally oval sidewall  104  extending between an upper surface  106  and a lower surface  108 . The sidewall  104  forms a pair of spaced apart rails  110  and  112  having respective upper surfaces  110 A and  112 A spaced above the upper surface  106  of the platform  102 .  
         [0062]     A rectangular-shaped bar  114  of a conductive material, such as of tantalum, titanium, nickel, molybdenum, niobium, cobalt, stainless steel, tungsten, platinum, palladium, gold, silver, copper, chromium, vanadium, aluminum, zirconium, hafnium, zinc, iron, and alloys thereof, comprises spaced apart right and left sidewalls  114 A and  114 B extending to front and back end walls  114 C and  114 D. These sidewalls and end walls extend to and meet with an upper surface  116  and a lower surface  118 .  
         [0063]     It is further within the scope of the invention that the conductive bar  114  can be made of any one of these materials, and alloys thereof, and then be provided with a coating on its upper surface of another one of them. This makes the conductive bar useful as a bonding pad for connection to a medical device. For example, the bar can be of nickel, aluminum, or platinum and be plated or coated with gold as a bonding pad or surface for connection to a medical device. Suitable wire bonding techniques useful with the conductive bar  114  include thermocompression ball bonding, thermosonic compressive wire bonding, ultrasonic compressive wedge bonding, thermocompression wedge bonding, stitch bonding, and tape automated bonding, among others. For more description regarding wire bonding a medical device to a conductive pad, reference is made to U.S. Pat. No. 6,626,680 to Ciurzynski et al., which is assigned to the assignee of the present invention and incorporated herein by reference.  
         [0064]     The conductive bar  114  is provided with spaced apart openings  120  and  122  that extend through the thickness from the upper surface  116  to the lower surface  118  thereof. The platform  102  is also provided with a pair of spaced apart openings  124  and  126  that extend through the thickness from the upper surface  106  to the lower surface  108  thereof. As particularly shown in  FIG. 8 , a lower portion of the openings  124 ,  126  is beveled with a frusto-conical shape extending downwardly and outwardly toward the lower platform surface  108 .  
         [0065]     As shown in FIGS.  6  to  8 , the capacitor interconnect  100  is formed by nesting the conductive bar  114  inside the rails  100  and  112  of the insulative platform  102 . In this position, the lower surface  118  of the bar  114  rests on the upper surface  106  of the platform  102  and the upper surfaces  110 A and  112 A of the rails are coplanar with the upper surface  116  of the conductive bar  114 . The right and left bar sidewalls  114 A,  114 B are in a closely spaced relationship with the respective rails  110 ,  112 . The front and back end walls  114 C,  114 D of the conductive bar  114  are aligned with the opposed ends of the rails  110 ,  112 . This leaves minor portions  102 A and  102 B at each end of the platform  102  uncovered by the bar.  
         [0066]     As shown in  FIG. 9 , the connection between the capacitors  12 ,  14  is made by first securing a pin  128  to the surrounding sidewall  70  of the casing portion  68  for capacitor  14 . In order to provide a robust connection, a flat piece of metal serving as a foot  130  is first secured to one end of the pin  128  and this assembly is then secured to the sidewall  70 , such as by welding. Pin  128  now serves as the negative polarity connection for the second capacitor  14 . As previously described with respect to FIGS.  1  to  4 , the anode lead  42  is the positive polarity termination for the first capacitor  12 .  
         [0067]     In order to effect a series connection between the positive polarity lead  42  and the negative polarity pin  128  of the side-by-side capacitors  12 ,  14 , the insulative platform  102  supporting the conductive bar  114  is moved into the position shown in  FIGS. 9 and 10 . In that manner, the positive polarity anode lead  42  is received in the aligned openings  124  and  120  and the negative polarity pin  128  is received in the aligned openings  126  and  122  in the respective platform  102  and conductive bar  114 . The beveled mouth to the platform openings  124 ,  126  helps with this positioning. The upper end of the lead  42  and pin  128  now extend above the upper surface  116  of the conductive bar  114 . A laser (not shown) is used to sever the excess extending material from the lead and pin and to weld them to the conductive bar in a secure electrical connection, as shown in  FIG. 11 .  
         [0068]     In this position, the lower surface  108  of the insulative platform  102  rests on the surrounding sidewalls  30 ,  74  of the casing portions  24  and  68  of the respective first and second capacitors  12 ,  14 . The platform  102  also rests on the foot  130  of the negative polarity pin  128  at the bevel of opening  126 . The capacitors, which have their respective casings electrically insulated from each other by the intermediate double-sided adhesive  94 , are now serially connected to each other by the conductive bar  114  of the interconnect  100  extending from the positive polarity lead  42  of capacitor  12  to the negative polarity pin  128  of capacitor  14 .  
         [0069]     In order to make electrical connection to the series connected capacitors  12 ,  14 , a footpad  132  secured to one end of a terminal lead  134  is secured to the casing of capacitor  14 . A positive polarity pin (not shown) extends from the opposite end of the capacitor  12  electrically insulated there from by a glass-to-metal feedthrough. The series connected capacitors  12 ,  14  are now connectable to a load through the lead  134  and positive polarity pin.  
         [0070]     The capacitor interconnect  100  provides many advantages over the previously described connecting tab  96  and anode lead  42  structure. Among them is that the welds of the lead  42  and pin  128  to the conductive bar  114  are easier to make, but are more robust with improved mechanical pull strength. This is without sharp edges and while occupying significantly less real estate.  
         [0071]     FIGS.  12  to  14  illustrate another embodiment of a capacitor interconnect  150  according to the present invention. This interconnect is similar to that of the first embodiment previously described with respect to FIGS.  5  to  11 . However, the insulative platform  152  is provided with a lower surface having a recess  154  centered between the openings  156 ,  158 . The recess extends laterally from straight sidewall portion  160  to straight sidewall portion  162  and is sized to receive and fit over the surrounding sidewalls  30 ,  74  of the casing portions  24 ,  68  of the respective capacitors  12 ,  14 . This provides a more stable footing for the interconnect  150  with the lower surface  164  of the insulative platform  152  resting on the surrounding sidewalls  26 ,  70  of the casing portions  22  and  66  of the respective first and second capacitors  12 ,  14 . The capacitors, which have their respective casings electrically insulated from each other by the intermediate double-sided adhesive  94 , are now serially connected to each other by the conductive bar  114  of the interconnect  150  extending from the positive polarity lead  42  of capacitor  12  to the negative polarity pin  128  of capacitor  14 .  
         [0072]     This embodiment also shows making electrical connection to the series connected capacitors  12 ,  14  by securing a footpad  166 /terminal lead  168  assembly to the casing of capacitor  14 . The assembly is of any conductive material previously described as being useful for conductive bar  114 . This is an alternative embodiment to the footpad  132 /terminal lead  134  assembly shown directly connected to the casing of capacitor  14  in  FIGS. 9 and 10 . A positive polarity pin (not shown) extends from the opposite end of the capacitor  12  electrically insulated there from by a glass-to-metal feedthrough.  
         [0073]      FIG. 15  is a cross-sectional view illustrating three side-by-side-by-side capacitors  12 ,  14  and  170  serially connected together using two interconnects  150 . The third capacitor  170  can be either the same as or different than the capacitors  12 ,  14 . However, for the sake of illustration, capacitor  170  is of an electrolytic type and is the same as capacitors  12 ,  14  in its physical structure.  
         [0074]     The casing for capacitor  170  is electrically insulated from that of capacitor  12  by an intermediate double-sided adhesive  94 . Then, the conductive bar  114  of the second interconnect  150  connects between a positive polarity pin  172  connected to the casing of capacitor  12  and the negative polarity lead  174  of capacitor  170 . A negative polarity pin  176  extends from the opposite end of capacitor  170 . Now, a load can be connected to the three serially connected capacitors  170 ,  12  and  14  by connecting to the positive polarity lead  80  of capacitor  14  and the negative polarity pin  176  of capacitor  170 . Of course, those skilled in the art will recognize that if the various interconnects of the present invention can be used to connect two and three capacitors in a serial configuration, they can be used to connect four and more, as dictated by a particular application.  
         [0075]     FIGS.  16  to  18  illustrate another embodiment of a capacitor interconnect  200  according to the present invention. This interconnect is similar to that of the interconnect  150  previously described with respect to FIGS.  12  to  14 . However, the insulative platform  202  has a surrounding oval-shaped sidewall  204  extending above an interior upper surface  206 . The sidewall  204  further has opposed protruding portions  208  and  210 . The lower surface  212  has a recess  214  centered between openings  216 ,  218  and extending laterally from opposed straight portions of sidewall  204 .  
         [0076]     The conductive bar  220  is an oval-shaped member of a similar material as bar  144  and comprises opposed openings  222  and  224  at either end with intermediate indentation portions  226  and  228 . In that respect, the conductive bar  220  is received in the space enclosed by the surrounding sidewall  204  resting on the upper surface  206  of the insulative platform  202 . The opposed protruding portions  208 ,  210  are sized to closely match the opposed indentation portions  226 ,  228  of the bar  220 . With the conductive bar  220  nested inside the surrounding platform sidewall  204 , the spaced apart openings  222  and  224  are exactly aligned with openings  216  and  218  in the insulative platform  202 . Also, the upper surface of the conductive bar  220  is coplanar with the upper surface of the surrounding platform sidewall  204 . Finally, the lower portions of the platform openings  216  and  218  are beveled to facilitate receiving the positive polarity anode lead  42  of capacitor  12  and the negative polarity pin  128  of capacitor  14  therein. As before, the upper end of lead  42  and pin  128  extending above the upper surface of the conductive bar  220  is removed when the conductive bar is welded to the lead and pin, such as by a laser.  
         [0077]     In this position, the lower surface  212  of the insulative platform  202  rests on the surrounding sidewalls  30 ,  74  of the casing portions  24  and  68  of the respective first and second capacitors  12 ,  14 . The insulative platform  202  also rests on the foot  130  of the negative polarity pin  128  at the bevel of opening  126 . The capacitors, which have their respective casings electrically insulated from each other by the intermediate double-sided adhesive  94 , are now serially connected to each other by the conductive bar  220  of the interconnect  200  extending from the positive polarity lead  42  of capacitor  12  to the negative polarity pin  128  of capacitor  14 . In a similar manner as the previously described bar  114 , conductive bar  220  is now a suitable structure for making a wire bond connection between the series connected capacitors  12 ,  14  and a medical device.  
         [0078]     As shown in  FIGS. 18A and 18B , to further facilitate a wire bond connection, the surrounding sidewall  204 A of the insulative platform  202 A is provided with a cutout  230  extending from the upper surface thereof to a distance spaced above the recess  214 A and centered between openings  216 A and  218 A. With the conductive bar  220  nested inside the surrounding platform sidewall  204 A, the cutout  230  exposes an edge portion  220 A of the bar. The conductive bar  220  can be of any of the previously listed materials, for example nickel, aluminum, or platinum plated or coated with gold. Gold can reside on the edge  220  as well as the upper surface thereof to provide a bonding pad or surface there for connection to the medical device  
         [0079]     FIGS.  19  to  22  relate to a further embodiment of a capacitor interconnect  250  according to the present invention. Interconnect  250  is in the shape of an elongated pocket or cap of a similar material as the previously described bar  144  and having an upper wall  252  supporting a surrounding sidewall  254  extending to an oval-shaped edge  256 . The sidewall  254  extends outwardly from the upper wall  252  to the edge  256  and provides an opening sized so that the cap interconnect fits over and receives the positive polarity anode lead  42  of capacitor  12  and the negative polarity pin  128  of capacitor  14 . However, the sidewall  254  is of a height to prevent the cap  250  from contacting the casings of the capacitors  12 ,  14 , as this will short them out.  
         [0080]     As shown in  FIG. 21 , the lead  42  and pin  128  reside adjacent to the opposite ends of the cap interconnect. The electrical connector is then made by physical deformation of the cap onto the lead and pin. First, a U-shaped backing plate  258  surrounds the cap interconnect  250  on three of its “sides”. A ram  260  then moves against the far portion of the surrounding sidewall  254 , crushing it down and into a locking relationship with the lead  42  and pin  128 . Preferably, this crushing force is sufficient to bring the opposed planar portions of the surrounding sidewall  254  into contact with each other.  
         [0081]     FIGS.  23  to  25  illustrate another embodiment of a capacitor interconnect  300  according to the present invention. Interconnect  300  is a tubular U-shaped sleeve of a similar material as the previously described bar  144  and having a central portion  302  supporting opposed legs  304  and legs  306 . The central portion  302  is of a length such that the cylindrically shaped openings in legs  304 ,  306  snuggly receive the positive polarity anode lead  42  of capacitor  12  and the negative polarity pin  128  of capacitor  14  in a co-axial relationship thereof. Welding the legs  304 ,  306  to the lead  42  and pin  128 , such as by using a laser  308  makes the electrical connection. A weldment  310  at each leg then effects the connection.  
         [0082]      FIG. 26  illustrates a further embodiment of a capacitor interconnect  350  according to the present invention. Interconnect  350  comprises the lead  42  and pin  128  having extending portions that were previously aligned in a side-by-side orientation and then subjected to a clamping force. This provides lead  42  having a distal portion  42 A lapping a distal portion  128 A of terminal pin  128 . The distal portions  42 A and  128 A provided in the side-by-side lap joint relationship are then secured together such as by a weldment  352  created by laser  354 .  
         [0083]      FIG. 27  illustrates a further embodiment of a capacitor interconnect  400  according to the present invention. Interconnect  400  comprises the lead  42  and pin  128  having respective L-shaped distal portions  32 B and  128 B that are secured together by an intermediate sleeve  402 . This is done by first fitting one end of the sleeve over one of lead  42  and pin  128 , for example the distal portion  42 B of lead. The double-sided adhesive layer  94  has previously been contacted to the major face  32  of the casing portion  24  for capacitor  12 . Capacitor  14  is then moved into place putting the capacitors  12 ,  14  in a side-by-side relationship with the face wall  76  of casing portion  68  contacting the other side of the adhesive  94 . As this occurs, the distal portion  128 B of pin  128  is fitted into the other end of sleeve  402 . A laser  404  is then used to secure the sleeve  402  to the distal portions  42 B and  128 B of the lead and pin. A weldment  406  is shown connecting the distal lead portion  42 B to the sleeve  402 .  
         [0084]     Thus, according to the present invention, adjacent capacitors are connectable in series by connecting the anode terminal lead from one to the casing of another. The anode terminal lead can be connected to the next capacitor&#39;s casing by any one of the interconnects  100 ,  150 ,  200 ,  250 ,  300 ,  350  and  400 . That way, any number of capacitors is serially connected together to increase the delivered capacity of the assembly. This is particularly important in advanced implantable medial devices, such as cardiac defibrillators, where delivered capacity coupled with reduced package volume is paramount in the minds of design engineers.  
         [0085]     It is appreciated that various modifications to the inventive concepts described herein may be apparent to those of ordinary skill in the art without departing from the spirit and scope of the present invention as defined by the appended claims.

Technology Classification (CPC): 8