Implantable medical device having flat electrolytic capacitor with consolidated electrode assembly

• US 6,006,133 A
• Filed: 06/24/1998
• Issued: 12/21/1999
• Est. Priority Date: 04/03/1998
• Status: Expired due to Term

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Breyen, Mark D., Johnson, William L., Lessar, Joseph F., Rorvick, Anthony W., Pignato, Paul A., Bullock, Norma K.
• Primary Examiner(s): Getzow, Scott M.
• Application Number:
  US09/103,967
• Time in Patent Office: 545 Days
• Field of Search: 29/25.03, 361/503, 361/504, 361/508, 361/509, 361/512, 361/516, 361/517, 361/518, 607/5
• US Class Current: 607/5
• CPC Class Codes: A61N 1/375 Constructional arrangements, e.g. casings
• CPC Class Codes: A61N 1/37512 Pacemakers
• CPC Class Codes: A61N 1/3956 Implantable devices for applying electric shocks to the heart, e.g. for cardioversion

Abstract

An implantable medical device such as a defibrillator is described. The device includes an hermetically sealed housing containing a flat electrolytic capacitor and an energy source such as a battery. The battery is connected to the capacitor and provides charge thereto. The capacitor stores the charge at a relatively high voltage. The charge stored in the capacitor is discharged through a defibrillation lead to a site on or in the heart when fibrillation of the heart is detected by the implantable medical device. Methods of making and using the implantable medical device, the capacitor, and their various components are disclosed.

Claims

1. An hermetically sealed implantable medical device, comprising:

(a) an hermetically sealed housing;

(b) an energy source disposed within the housing;

(c) a substantially flat aluminum electrolytic capacitor connected to the energy source and disposed within the housing, the capacitor comprising;

(i) at least one flat cathode layer having no holes for registration disposed therethrough, the cathode layer being formed of cathode foil and having a first perimeter of a first overall length, the cathode layer having top and bottom surfaces and at least a first tab projecting from the first perimeter at a first predetermined perimeter location;

(ii) a plurality of flat anode layers formed of anode foil having no holes for registration disposed therethrough, the plurality of anode layers forming an anode sub-assembly having top and bottom surfaces, at least one of the plurality of anode layers being a first anode layer having a second perimeter of a second overall length and at least a second tab projecting from the second perimeter at a second predetermined perimeter location;

(iii) at least first and second separator layers formed of separator material, the first and second separator layers defining third and fourth perimeters of substantially equal overall lengths, respectively, and substantially equal third and fourth physical dimensions respecting area, respectively;

(iv) a case having sidewalls extending upwardly from a flat planar base to form an open end, the intersection of the sidewalls and planar base defining a fifth perimeter having a fifth overall length, the fifth perimeter having fifth physical dimensions respecting area;

(v) a cover for sealing the open end of the case;

(vi) a liquid electrolyte disposed within the case;

wherein the at least one cathode layer, the plurality of anode layers and the first and second separator layers are vertically stacked in the case to form an electrode assembly such that the first and second separator layers are disposed, respectively, atop and beneath the top and bottom surfaces of the anode sub-assembly and the cathode layer is disposed atop the first separator layer or beneath the second separator layer, the first tab is aligned with a first predetermined registration position in the electrode assembly and the second tab is aligned with a second predetermined registration position in the electrode assembly, the lengths of the third and fourth perimeters each substantially equalling the fifth length, the third and fourth physical dimensions each substantially equalling the fifth physical dimensions, the third, fourth and fifth lengths and third, fourth and fifth physical dimensions exceeding those of the first and second lengths and the first and second physical dimensions, respectively, the perimeters of the first and second separator layers being substantially co-extensive with and propinqaunt to the fifth perimeter, the first and second perimeters of the anode and cathode layers being spaced apart from the fifth perimeter, the electrolyte causing the at least first and second separator layers to swell against one another when the electrolyte is introduced inside the case and the cover is sealingly disposed over the open end of the case, the thus swelled separator layers positionally securing, or contributing to the positional securing of, the electrode assembly in place within the case.

2. The device of claim 1, wherein the cathode layer is formed from aluminum cathode foil.

3. The device of claim 1, wherein the anode layers are formed of through-etched aluminum anode foil.

4. The device of claim 1, wherein each anode layer has a specific capacitance selected from the group consisting of at least about 0.3 microfarads/cm², at least about 0.5 microfarads/cm², and at least about 0.8 microfarads/cm².

5. The device of claim 1, wherein each anode layer has a thickness selected from the group consisting of from about 20 micrometers to about 300 micrometers, from about 40 micrometers to about 200 micrometers, from about 60 micrometers to about 150 micrometers, and from about 70 micrometers to about 140 micrometers.

6. The device of claim 1, wherein the cathode layer is formed from a highly etched cathode foil.

7. The device of claim 1, wherein the cathode layer is formed from a aluminum cathode foil having a specific capacitance selected from the group consisting of at least about 100 microfarads/cm², at least about 200 microfarads/cm², at least about 250 microfarads/cm², and at least about 300 microfarads/cm².

8. The device of claim 1, wherein the cathode layer is formed from aluminum foil having a thickness selected from the group consisting of from about 10 micrometers to about 200 micrometers, from about 15 micrometers to about 150 micrometers, from about 20 micrometers to about 100 micrometers, from about 25 micrometers to about 75 micrometers, and about 30 micrometers.

9. The device of claim 1, wherein the anode sub-assembly comprises a plurality of non-notched anode layers and at least one notched anode layer.

10. The device of claim 1, wherein the anode layers in the anode sub-assembly are cold welded together.

11. The device of claim 1, wherein at least one of the first and the second separator layers is pressure bonded to the anode sub-assembly.

12. The device of claim 1, wherein the top and bottom surfaces of the anode sub-assembly are covered by the first separator layer and the second separator layer.

13. The device of claim 1, wherein the separator layer has a perimeter extending beyond the perimeter of the anode sub-assembly.

14. The device of claim 1, wherein the implantable medical device is selected from the group consisting of a PCD, an AID, an ICD, a defibrillator, an implantable pulse generator and a pacemaker.

15. The device claim 1, wherein the energy source is selected from the group consisting of a battery, an electrochemical cell, a primary electrochemical cell, a secondary or rechargeable electrochemical cell, an electrochemical cell comprising a lithium-containing anode, an electrochemical cell comprising a silver vanadium oxide-containing cathode, an electrochemical cell comprising a (CF_n)_x -containing cathode, an electrochemical cell comprising a cathode containing a mixture of silver vanadium oxide and (CF_n)_x, a spirally wound electrochemical cell, an electrochemical cell having a plurality of plate-shaped electrodes, and an electrochemical cell having at least one serpentine electrode disposed therewithin.

16. The device of claim 1, wherein the plurality of anode layers is connected electrically to the case.

17. The device of claim 1, wherein the at least one cathode layer is electrically connected to the case.

18. The device of claim 1, wherein the case is connected electrically to neither the at least one cathode layer nor to the plurality of anode layers.

19. The device of claim 1, wherein the electrode assembly is secured by means for securing the electrode assembly to prevent electrode assembly movement or shifting.

20. The device of claim 19, wherein the means for securing the electrode assembly comprises an electrode wrap and corresponding adhesive strip.

21. The device of claim 1, wherein at least portions of the first and second separator layers are secured together at the peripheries thereof by at least one of stitching, adhesive bonding, ultrasonic paper welding or direct pressure bonding.

22. The device of claim 1, wherein the case is formed of aluminum or aluminum alloy.

23. The device of claim 1, wherein the capacitor further comprises a second cathode layer formed of cathode foil and a third separator layer formed of separator material, the second cathode layer having top and bottom surfaces and at least a third tab projecting from the third perimeter at a third predetermined perimeter location, the second cathode layer and the third separator layer being included within the electrode assembly such that the third separator layer is disposed between the top surface of the anode sub-assembly and the bottom surface of the second cathode layer, the first tab and the third tab being vertically aligned such that the first predetermined registration location of the electrode assembly coincides vertically with the third predetermined registration location of the electrode assembly.

24. The device of claim 1, wherein the capacitor further comprises a third separator layer formed of separator material and a second anode sub-assembly having top and bottom surfaces and comprising a plurality of anode layers formed of anode foil, at least one of the plurality of anode layers of the second anode sub-assembly being a fourth anode layer having a fourth perimeter, at least a fourth tab projecting from the fourth perimeter at a fourth predetermined perimeter location, vertically stacking the second anode sub-assembly and the third separator layer in the stacked electrode assembly such that the third separator layer is disposed beneath the first separator layer and the second anode sub-assembly is disposed between the first and third separator layers, and vertically aligning the second tab and the fourth tab such that the second predetermined registration location of the electrode assembly coincides vertically with the fourth predetermined registration location of the electrode assembly.

25. An hermetically sealed implantable medical device, comprising:

(a) an hermetically sealed housing;

(b) an energy source disposed within the housing;

(c) a substantially flat electrolytic capacitor connected to the energy source and disposed within the housing, the capacitor comprising;

(1) at least one flat cathode layer having no holes for registration disposed therethrough, the cathode layer being formed of cathode foil and having a first perimeter of a first overall length, the cathode layer having at least a first tab projecting from the first perimeter at a first predetermined perimeter location;

(2) a plurality of flat anode layers formed of anode foil having no holes for registration disposed therethrough, the plurality of anode layers forming an anode sub-assembly, at least one of the plurality of anode layers being a first anode layer having a second perimeter of a second length and at least a second tab projecting from the second perimeter at a second predetermined perimeter location;

(3) at least one separator layer formed of separator material, the separator layer having a third perimeter of a third length;

(4) at least one separator envelope comprising upper and lower surfaces formed of separator material, the upper and lower surfaces of the separator envelope having fourth and fifth perimeters of fourth and fifth lengths, respectively;

(5) a case having sidewalls extending upwardly from a flat planar base to form an open end;

(6) a cover for sealing the open end of the case;

wherein the at least one cathode layer, the plurality of anode layers, and the at least one separator layer are vertically stacked between the upper and lower surfaces of the separator envelope and therewithin such that the at least one separator layer is disposed between the at least one cathode layer and the anode sub-assembly, the lengths of the first and second perimeters each being less than the respective lengths of the third, fourth and fifth perimeters, the fourth and fifth perimeters being joined together over at least a portion thereof to register and align the first tab in a first predetermined registration location and the second tab in a second predetermined registration location, the stacked at least one cathode layer, plurality of anode layers, at least one separator layer and separator envelope forming an electrode assembly, the electrode assembly being disposed within the open end of the case, the cover being sealingly disposed over the open end of the case.

26. The capacitor of claim 25, further comprising a second cathode layer formed of cathode foil and having a third perimeter, and a third separator layer formed of separator material, the second cathode layer having top and bottom surfaces and at least a third tab projecting from the third perimeter at a third predetermined perimeter location, the second cathode layer and the third separator layer being included within the separator envelope such that the third separator layer is disposed between the top surface of the anode sub-assembly and the bottom surface of the second cathode layer, the first tab and the third tab being vertically aligned such that the first predetermined registration location of the electrode assembly coincides vertically with the third predetermined registration location of the electrode assembly.

27. The capacitor of claim 25, further comprising a third separator layer formed of separator material and a second anode sub-assembly having top and bottom surfaces and comprising a plurality of anode layers formed of aluminum anode foil, at least one of the plurality of anode layers of the second anode sub-assembly being a fourth anode layer having a fourth perimeter, at least a fourth tab projecting from the fourth perimeter at a fourth predetermined perimeter location, the second anode sub-assembly and the third separator layer being included within the separator envelope such that the third separator layer is disposed beneath the first separator layer and the second anode sub-assembly is disposed between the first and third separator layers, the second tab and the fourth tab being vertically aligned such that the second predetermined registration location of the electrode assembly coincides vertically with the fourth predetermined registration location of the electrode assembly.

28. The device of claim 25, wherein the cathode layer is formed from aluminum cathode foil.

29. The device of claim 25, wherein the anode layers are formed of through-etched aluminum anode foil.

30. The device of claim 25, wherein each anode layer has a specific capacitance selected from the group consisting of at least about 0.3 microfarads/cm², at least about 0.5 microfarads/cm², and at least about 0.8 microfarads/cm².

31. The device of claim 25, wherein each anode layer has a thickness selected from the group consisting of from about 20 micrometers to about 300 micrometers, from about 40 micrometers to about 200 micrometers, from about 60 micrometers to about 150 micrometers, and from about 70 micrometers to about 140 micrometers.

32. The device of claim 25, wherein the cathode layer is formed from a highly etched cathode foil.

33. The device of claim 25, wherein the cathode layer is formed from a aluminum cathode foil having a specific capacitance selected from the group consisting of at least about 100 microfarads/cm², at least about 200 microfarads/cm², at least about 250 microfarads/cm², and at least about 300 microfarads/cm².

34. The device of claim 25, wherein the cathode layer is formed from aluminum foil having a thickness selected from the group consisting of from about 10 micrometers to about 200 micrometers, from about 15 micrometers to about 150 micrometers, from about 20 micrometers to about 100 micrometers, from about 25 micrometers to about 75 micrometers, and about 30 micrometers.

35. The device of claim 25, wherein the anode sub-assembly comprises a plurality of non-notched anode layers and at least one notched anode layer.

36. The device of claim 25, wherein the anode layers in the anode sub-assembly are cold welded together.

37. The device of claim 25, wherein at least one of the first and the second separator layers is pressure bonded to the anode sub-assembly.

38. The device of claim 25, wherein the top and bottom surfaces of the anode sub-assembly are covered by the first separator layer and the second separator layer.

39. The device of claim 25, wherein the separator layer has a perimeter extending beyond the perimeter of the anode sub-assembly.

40. The device of claim 25, wherein the implantable medical device is selected from the group consisting of a PCD, an AID, an ICD, a defibrillator, an implantable pulse generator and a pacemaker.

41. The device claim 25, wherein the energy source is selected from the group consisting of a battery, an electrochemical cell, a primary electrochemical cell, a secondary or rechargeable electrochemical cell, an electrochemical cell comprising a lithium-containing anode, an electrochemical cell comprising a silver vanadium oxide-containing cathode, an electrochemical cell comprising a (CF_n)_x -containing cathode, an electrochemical cell comprising a cathode containing a mixture of silver vanadium oxide and (CF_n)_x, a spirally wound electrochemical cell, an electrochemical cell having a plurality of plate-shaped electrodes, and an electrochemical cell having at least one serpentine electrode disposed therewithin.

42. The device of claim 25, wherein the plurality of anode layers is connected electrically to the case.

43. The device of claim 25, wherein the at least one cathode layer is electrically connected to the case.

44. The device of claim 25, wherein the case is connected electrically to neither the at least one cathode layer nor to the plurality of anode layers.

45. The device of claim 25, wherein the electrode assembly is secured by means for securing the electrode assembly to prevent electrode assembly movement or shifting.

46. The device of claim 45, wherein the means for securing the electrode assembly comprises an electrode wrap and corresponding adhesive strip.

47. The device of claim 25, wherein at least portions of the first and second separator layers are secured together at the peripheries thereof by at least one of stitching, adhesive bonding, ultrasonic paper welding or direct pressure bonding.

48. The device of claim 25, wherein the case is formed of aluminum or aluminum alloy.

49. A method of making an hermetically sealed implantable medical device, comprising the steps of:

(a) providing a housing for the implantable medical device;

(b) providing and disposing an energy source within the housing;

(c) providing components for a substantially flat electrolytic capacitor, comprising the steps of;

(1) providing at least one flat cathode layer having no holes for registration disposed therethrough, the cathode layer being formed of cathode foil and having a first perimeter of a first overall length, the cathode layer having top and bottom surfaces and at least a first tab projecting from the first perimeter at a first predetermined perimeter location;

(2) providing a plurality of flat anode layers formed of anode foil having no holes for registration disposed therethrough, the plurality of anode layers forming an anode sub-assembly having top and bottom surfaces, at least one of the plurality of anode layers being a first anode layer having a second perimeter of a second overall length and at least a second tab projecting from the second perimeter at a second predetermined perimeter location;

(3) providing at least first and second separator layers formed of separator material, the first and second separator layers defining third and fourth perimeters of substantially equal overall lengths, respectively, and substantially equal third and fourth physical dimensions, respectively;

(4) providing a case having sidewalls extending upwardly from a flat planar base to form an open end, the intersection of the sidewalls and planar base defining a fifth perimeter of a fifth overall length, the fifth perimeter having fifth physical dimensions;

(5) providing a cover for sealing the open end of the case;

(6) providing a liquid electrolyte for the capacitor;

(d) assembling the components of the capacitor such that the at least one cathode layer, the plurality of anode layers and the first and second separator layers are vertically stacked in the case to form an electrode assembly, the first separator layer being disposed between the bottom surface of the at least one cathode layer and the planar base, the second separator layer being disposed between the top surface of the at least one cathode layer and the bottom surface of the anode sub-assembly, the first tab being aligned with a first predetermined registration position in the electrode assembly, the second tab being aligned with a second predetermined registration position in the electrode assembly, the lengths of the third and fourth perimeters each substantially equalling the fifth length, the third and fourth physical dimensions each substantially equalling the fifth physical dimensions, the third, fourth and fifth lengths and third, fourth and fifth physical dimensions exceeding those of the first and second lengths and the first and second physical dimensions, respectively, the perimeters of the first and second separator layers being substantially co-extensive with and propinqaunt to the fifth perimeter, the first and second perimeters of the anode and cathode layers being spaced apart from the fifth perimeter, the cover being sealingly disposed over the open end of the case, the electrolyte being introduced inside the case and causing the first and second separator layers to swell against one another, the thus swelled separator layers positionally securing, or contributing to the positional securing of, the electrode assembly in place within the case;

(e) placing the capacitor in the housing and connecting the energy source to the capacitor, and

(f) hermetically sealing the housing of the implantable medical device.

50. The method of claim 49, wherein the steps of providing and assembling capacitor components further comprise the steps of providing a second cathode layer formed of aluminum cathode foil and having a third perimeter, and providing a third separator layer formed of separator material, the second cathode layer having top and bottom surfaces and at least a third tab projecting from the third perimeter at a third predetermined perimeter location, vertically stacking the second cathode layer and the third separator layer in the electrode assembly such that the third separator layer is disposed between the top surface of the anode sub-assembly and the bottom surface of the second cathode layer, and vertically aligning the first tab and the third tab such that the first predetermined registration location of the electrode assembly coincides vertically with the third predetermined registration location of the electrode assembly.

51. The method of claim 49, wherein the steps of providing and assembling capacitor components further comprise the steps of providing a third separator layer formed of separator material, and providing a second anode sub-assembly having top and bottom surfaces and comprising a plurality of anode layers formed of aluminum anode foil, at least one of the plurality of anode layers of the second anode sub-assembly being a fourth anode layer having a fourth perimeter, at least a fourth tab projecting from the fourth perimeter at a fourth predetermined perimeter location, vertically stacking the second anode sub-assembly and the third separator layer in the stacked electrode assembly such that the third separator layer is disposed beneath the first separator layer and the second anode sub-assembly disposed between the first and third separator layers, and vertically aligning the second tab and the fourth tab such that the second predetermined registration location of the electrode assembly coincides vertically with the fourth predetermined registration location of the electrode assembly.

52. The method of claim 49, wherein the housing providing step further comprises the step of providing a housing for an implantable medical device selected from the group consisting of a PCD, an AID, an ICD, a defibrillator, an implantable pulse generator and a pacemaker.

53. The method of claim 49, wherein the energy source providing step is preceded by the step of selecting the energy source from the group consisting of a battery, an electrochemical cell, a primary electrochemical cell, a secondary or rechargeable electrochemical cell, an electrochemical cell comprising a lithium-containing anode, an electrochemical cell comprising a silver vanadium oxide-containing cathode, an electrochemical cell comprising a (CF_n)_x -containing cathode, an electrochemical cell comprising a cathode containing a mixture of silver vanadium oxide and (CF_n)_x, and a spirally wound electrochemical cell.

54. The method of claim 49, wherein the cathode layer providing step further comprises providing a cathode layer formed from aluminum cathode foil.

55. The method of claim 49, wherein the step of providing the plurality of anode layers further comprises the step of providing anode layers formed of through-etched aluminum anode foil.

56. The method of claim 49, wherein the step of providing the plurality of anode layers further comprises the step of providing, for each anode layer, an anode layer having a specific capacitance selected from the group consisting of at least about 0.3 microfarads/cm², at least about 0.5 microfarads/cm², and at least about 0.8 microfarads/cm².

57. The method of claim 49, wherein the step of providing the plurality of anode layers further comprises the step of providing, for each anode layer, an anode layer having a thickness selected from the group consisting of from about 20 micrometers to about 300 micrometers, from about 40 micrometers to about 200 micrometers, from about 60 micrometers to about 150 micrometers, and from about 70 micrometers to about 140 micrometers.

58. The method of claim 49, wherein the cathode layer providing step further comprises providing a cathode layer formed from a highly etched cathode foil.

59. The method of claim 49, wherein the cathode layer providing step further comprises providing a cathode layer formed from an aluminum cathode foil having a specific capacitance selected from the group consisting of at least about 100 microfarads/cm², at least about 200 microfarads/cm², at least about 250 microfarads/cm², and at least about 300 microfarads/cm².

60. The method of claim 49, wherein the cathode layer providing step further comprises providing a cathode layer formed from aluminum foil having a thickness selected from the group consisting of from about 10 micrometers to about 200 micrometers, from about 15 micrometers to about 150 micrometers, from about 20 micrometers to about 100 micrometers, from about 25 micrometers to about 75 micrometers, and about 30 micrometers.

61. The method of claim 49, wherein the anode layer providing step further comprises the step of providing a plurality of non-notched anode layers and at least one notched anode layer.

62. The method of claim 49, wherein the assembling step further includes the step of cold welding the anode layers in the anode sub-assembly together.

63. The method of claim 49, wherein the assembling step further includes the step of pressure welding the first and the second separator layers to the anode sub-assembly.

64. The method of claim 49, wherein the assembling step further includes the step of covering the top and bottom surfaces of the anode subassembly with the first separator layer and the second separator layer.

65. The method of claim 49, wherein the separator providing step is preceded by a step of selecting the first and second separator layers such that the first and second separator layers have perimeters extending beyond the perimeter of the anode sub-assembly.

66. The method of claim 49, further comprising the step of selecting the implantable medical device from the group consisting of a PCD, an AID, an ICD, a defibrillator, an implantable pulse generator and a pacemaker.

67. The method of claim 49, further comprising the step of selecting the energy source from the group consisting of a battery, an electrochemical cell, a primary electrochemical cell, a secondary or rechargeable electrochemical cell, an electrochemical cell comprising a lithium-containing anode, an electrochemical cell comprising a silver vanadium oxide-containing cathode, an electrochemical cell comprising a (CF_n)_x -containing cathode, an electrochemical cell comprising a cathode containing a mixture of silver vanadium oxide and (CF_n)_x, a spirally wound electrochemical cell, an electrochemical cell having a plurality of plate-shaped electrodes, and an electrochemical cell having at least one serpentine electrode disposed therewithin.

68. The method of claim 49, further comprising the step of electrically connecting the at least one cathode layer to the case.

69. The method of claim 49, further comprising the step of not electrically connecting the case to the at least one cathode layer or to the plurality of anode layers.

70. The method of claim 49, further comprising the step of securing the electrode assembly with means for securing the electrode assembly to prevent electrode assembly movement or shifting.

71. The method of claim 70, wherein the electrode assembly securing step further comprises the step of securing the electrode assembly with an electrode wrap and corresponding adhesive strip.

72. The method of claim 49, further comprising the step of securing at least portions of the first and second separator layers together at the peripheries thereof by at least one of stitching, adhesive bonding, ultrasonic paper welding or direct pressure bonding.

73. The method of claim 49, wherein the case providing step is preceded by the step of forming the case from aluminum or aluminum alloy.

74. A substantially flat electrolytic capacitor suitable for use in an hermetically sealed implantable medical device, comprising:

(a) at least one flat cathode layer having no holes for registration disposed therethrough, the cathode layer being formed of cathode foil and having a first perimeter of a first overall length, the cathode layer having top and bottom surfaces and at least a first tab projecting from the first perimeter at a first predetermined perimeter location;

(b) a plurality of flat anode layers formed of anode foil having no holes for registration disposed therethrough, the plurality of anode layers forming an anode sub-assembly having top and bottom surfaces, at least one of the plurality of anode layers being a first anode layer having a second perimeter of a second overall length and at least a second tab projecting from the second perimeter at a second predetermined perimeter location;

(c) at least first and second separator layers formed of separator material, the first and second separator layers defining third and fourth perimeters of substantially equal overall lengths, respectively, and substantially equal third and fourth physical dimensions, respectively;

(d) a case having sidewalls extending upwardly from a flat planar base to form an open end, the intersection of the sidewalls and planar base defining a fifth perimeter of a fifth overall length, the fifth perimeter having fifth physical dimensions;

(e) a cover for sealing the open end of the case;

(f) a liquid electrolyte disposed within the case;

wherein the at least one cathode layer, the plurality of anode layers and the first and second separator layers are vertically stacked in the case to form an electrode assembly such that the first separator layer is disposed between the bottom surface of the at least one cathode layer and the planar base, the second separator layer is disposed between the top surface of the at least one cathode layer and the bottom surface of the anode sub-assembly, the first tab is aligned with a first predetermined registration position in the electrode assembly and the second tab is aligned with a second predetermined registration position in the electrode assembly, the lengths of the third and fourth perimeters each substantially equalling the fifth length, the third and fourth physical dimensions each substantially equalling the fifth physical dimensions, the third, fourth and fifth lengths and third, fourth and fifth physical dimensions exceeding those of the first and second lengths and the first and second physical dimensions, respectively, the perimeters of the first and second separator layers being substantially co-extensive with and propinqaunt to the fifth perimeter, the first and second perimeters of the anode and cathode layers being spaced apart from the fifth perimeter, the electrolyte causing the first and second separator layers to swell against one another when the electrolyte is introduced inside the case and the cover is sealingly disposed over the open end of the case, the thus swelled separator layers positionally securing, or contributing to the positional securing of, the electrode assembly in place within the case.

75. The capacitor of claim 74, further comprising a second cathode layer formed of cathode foil and having a third perimeter, and a third separator layer formed of separator material, the second cathode layer having top and bottom surfaces and at least a third tab projecting from the third perimeter at a third predetermined perimeter location, the second cathode layer and the third separator layer being included within the electrode assembly such that the third separator layer is disposed between the top surface of the anode sub-assembly and the bottom surface of the second cathode layer, the first tab and the third tab being vertically aligned such that the first predetermined registration location of the electrode assembly coincides vertically with the third predetermined registration location of the electrode assembly.

76. The capacitor of claim 74, further comprising a third separator layer formed of separator material and a second anode sub-assembly having top and bottom surfaces and comprising a plurality of anode layers formed of aluminum anode foil, at least one of the plurality of anode layers of the second anode sub-assembly being a fourth anode layer having a fourth perimeter, at least a fourth tab projecting from the fourth perimeter at a fourth predetermined perimeter location, vertically stacking the second anode sub-assembly and the third separator layer in the stacked electrode assembly such that the third separator layer is disposed beneath the first separator layer and the second anode sub-assembly is disposed between the first and third separator layers, and vertically aligning the second tab and the fourth tab such that the second predetermined registration location of the electrode assembly coincides vertically with the fourth predetermined registration location of the electrode assembly.

77. The device of claim 74, wherein the cathode layer is formed from aluminum cathode foil.

78. The device of claim 74, wherein the anode layers are formed of through-etched aluminum anode foil.

79. The device of claim 74, wherein each anode layer has a specific capacitance selected from the group consisting of at least about 0.3 microfarads/cm², at least about 0.5 microfarads/cm², and at least about 0.8 microfarads/cm².

80. The device of claim 74, wherein each anode layer has a thickness selected from the group consisting of from about 20 micrometers to about 300 micrometers, from about 40 micrometers to about 200 micrometers, from about 60 micrometers to about 150 micrometers, and from about 70 micrometers to about 140 micrometers.

81. The device of claim 74, wherein the cathode layer is formed from a highly etched cathode foil.

82. The device of claim 74, wherein the cathode layer is formed from a aluminum cathode foil having a specific capacitance selected from the group consisting of at least about 100 microfarads/cm², at least about 200 microfarads/cm², at least about 250 microfarads/cm², and at least about 300 microfarads/cm².

83. The device of claim 74, wherein the cathode layer is formed from aluminum foil having a thickness selected from the group consisting of from about 10 micrometers to about 200 micrometers, from about 15 micrometers to about 150 micrometers, from about 20 micrometers to about 100 micrometers, from about 25 micrometers to about 75 micrometers, and about 30 micrometers.

84. The device of claim 74, wherein the anode sub-assembly comprises a plurality of non-notched anode layers and at least one notched anode layer.

85. The device of claim 74, wherein the anode layers in the anode sub-assembly are cold welded together.

86. The device of claim 74, wherein at least one of the first and the second separator layers is pressure bonded to the anode sub-assembly.

87. The device of claim 74, wherein the top and bottom surfaces of the anode sub-assembly are covered by the first separator layer and the second separator layer.

88. The device of claim 74, wherein the separator layer has a perimeter extending beyond the perimeter of the anode sub-assembly.

89. The device of claim 74, wherein the implantable medical device is selected from the group consisting of a PCD, an AID, an ICD, a defibrillator, an implantable pulse generator and a pacemaker.

90. The device claim 74, wherein the energy source is selected from the group consisting of a battery, an electrochemical cell, a primary electrochemical cell, a secondary or rechargeable electrochemical cell, an electrochemical cell comprising a lithium-containing anode, an electrochemical cell comprising a silver vanadium oxide-containing cathode, an electrochemical cell comprising a (CF_n)_x -containing cathode, an electrochemical cell comprising a cathode containing a mixture of silver vanadium oxide and (CF_n)_x, a spirally wound electrochemical cell, an electrochemical cell having a plurality of plate-shaped electrodes, and an electrochemical cell having at least one serpentine electrode disposed therewithin.

91. The device of claim 74, wherein the plurality of anode layers is connected electrically to the case.

92. The device of claim 74, wherein the at least one cathode layer is electrically connected to the case.

93. The device of claim 74, wherein the case is connected electrically to neither the at least one cathode layer nor to the plurality of anode layers.

94. The device of claim 74, wherein the electrode assembly is secured by means for securing the electrode assembly to prevent electrode assembly movement or shifting.

95. The device of claim 94, wherein the means for securing the electrode assembly comprises an electrode wrap and corresponding adhesive strip.

96. The device of claim 74, wherein at least portions of the first and second separator layers are secured together at the peripheries thereof by at least one of stitching, adhesive bonding, ultrasonic paper welding or direct pressure bonding.

97. The device of claim 74, wherein the case is formed of aluminum or aluminum alloy.

98. A substantially flat electrolytic capacitor suitable for use in an hermetically sealed implantable medical device, comprising:

(a) at least one flat cathode layer having no holes for registration disposed therethrough, the cathode layer being formed of cathode foil and having a first perimeter of a first overall length, the cathode layer having top and bottom surfaces and at least a first tab projecting from the first perimeter at a first predetermined perimeter location;

(b) a plurality of flat anode layers formed of anode foil having no holes for registration disposed therethrough, the plurality of anode layers forming an anode sub-assembly having top and bottom surfaces, at least one of the plurality of anode layers being a first anode layer having a second perimeter of a second overall length and at least a second tab projecting from the second perimeter at a second predetermined perimeter location;

(c) at least first and second separator layers formed of separator material, the first and second separator layers defining third and fourth perimeters of substantially equal overall lengths, respectively, and substantially equal third and fourth physical dimensions, respectively;

(d) a case having sidewalls extending upwardly from a flat planar base to form an open end, the intersection of the sidewalls and planar base defining a fifth perimeter of a fifth overall length, the fifth perimeter having fifth physical dimensions;

(e) a cover for sealing the open end of the case;

(f) an electrode assembly wrap;

wherein the at least one cathode layer, the plurality of anode layers and the first and second separator layers are vertically stacked in the case to form an electrode assembly having a periphery disposed thereabout such that the first separator layer is disposed between the bottom surface of the at least one cathode layer and the planar base, the second separator layer is disposed between the top surface of the at least one cathode layer and the bottom surface of the anode sub-assembly, the first tab is aligned with a first predetermined registration position in the electrode assembly, and the second tab is aligned with a second predetermined registration position in the electrode assembly, the electrode assembly wrap being disposed about the periphery of the electrode assembly to secure and immobilize the anode and cathode layers contained in the electrode assembly, the cover being sealingly disposed over the open end of the case.

99. The capacitor of claim 98, further comprising a second cathode layer formed of aluminum cathode foil and having a third perimeter, and a third separator layer formed of separator material, the second cathode layer having top and bottom surfaces and at least a third tab projecting from the third perimeter at a third predetermined perimeter location, the second cathode layer and the third separator layer being included within the electrode assembly such that the third separator layer is disposed between the top surface of the anode sub-assembly and the bottom surface of the second cathode layer, the first tab and the third tab being vertically aligned such that the first predetermined registration location of the electrode assembly coincides vertically with the third predetermined registration location of the electrode assembly.

100. The capacitor of claim 98, further comprising a third separator layer formed of separator material and a second anode sub-assembly having top and bottom surfaces and comprising a plurality of anode layers formed of anode foil, at least one of the plurality of anode layers of the second anode sub-assembly being a fourth anode layer having a fourth perimeter, at least a fourth tab projecting from the fourth perimeter at a fourth predetermined perimeter location, vertically stacking the second anode sub-assembly and the third separator layer in the stacked electrode assembly such that the third separator layer is disposed beneath the first separator layer and the second anode sub-assembly is disposed between the first and third separator layers, and vertically aligning the second tab and the fourth tab such that the second predetermined registration location of the electrode assembly coincides vertically with the fourth predetermined registration location of the electrode assembly.

101. The device of claim 98, wherein the cathode layer is formed from aluminum cathode foil.

102. The device of claim 98, wherein the anode layers are formed of through-etched aluminum anode foil.

103. The device of claim 98, wherein each anode layer has a specific capacitance selected from the group consisting of at least about 0.3 microfarads/cm², at least about 0.5 microfarads/cm², and at least about 0.8 microfarads/cm².

104. The device of claim 98, wherein each anode layer has a thickness selected from the group consisting of from about 20 micrometers to about 300 micrometers, from about 40 micrometers to about 200 micrometers, from about 60 micrometers to about 150 micrometers, and from about 70 micrometers to about 140 micrometers.

105. The device of claim 98, wherein the cathode layer is formed from a highly etched cathode foil.

106. The device of claim 98, wherein the cathode layer is formed from a aluminum cathode foil having a specific capacitance selected from the group consisting of at least about 100 microfarads/cm², at least about 200 microfarads/cm², at least about 250 microfarads/cm², and at least about 300 microfarads/cm².

107. The device of claim 98, wherein the cathode layer is formed from aluminum foil having a thickness selected from the group consisting of from about 10 micrometers to about 200 micrometers, from about 15 micrometers to about 150 micrometers, from about 20 micrometers to about 100 micrometers, from about 25 micrometers to about 75 micrometers, and about 30 micrometers.

108. The device of claim 98, wherein the anode sub-assembly comprises a plurality of non-notched anode layers and at least one notched anode layer.

109. The device of claim 98, wherein the anode layers in the anode sub-assembly are cold welded together.

110. The device of claim 98, wherein at least one of the first and the second separator layers is pressure bonded to the anode sub-assembly.

111. The device of claim 98, wherein the top and bottom surfaces of the anode sub-assembly are covered by the first separator layer and the second separator layer.

112. The device of claim 98, wherein the separator layer has a perimeter extending beyond the perimeter of the anode sub-assembly.

113. The device of claim 98, wherein the implantable medical device is selected from the group consisting of a PCD, an AID, an ICD, a defibrillator, an implantable pulse generator and a pacemaker.

114. The device claim 98, wherein the energy source is selected from the group consisting of a battery, an electrochemical cell, a primary electrochemical cell, a secondary or rechargeable electrochemical cell, an electrochemical cell comprising a lithium-containing anode, an electrochemical cell comprising a silver vanadium oxide-containing cathode, an electrochemical cell comprising a (CF_n)_x -containing cathode, an electrochemical cell comprising a cathode containing a mixture of silver vanadium oxide and (CF_n)_x, a spirally wound electrochemical cell, an electrochemical cell having a plurality of plate-shaped electrodes, and an electrochemical cell having at least one serpentine electrode disposed therewithin.

115. The device of claim 98, wherein the plurality of anode layers is connected electrically to the case.

116. The device of claim 98, wherein the at least one cathode layer is electrically connected to the case.

117. The device of claim 98, wherein the case is connected electrically to neither the at least one cathode layer nor to the plurality of anode layers.

118. The device of claim 98, wherein at least portions of the first and second separator layers are secured together at the peripheries thereof by at least one of stitching, adhesive bonding, ultrasonic paper welding or direct pressure bonding.

119. The device of claim 98, wherein the case is formed of aluminum or aluminum alloy.

120. A substantially flat electrolytic capacitor suitable for use in an hermetically sealed implantable medical device, comprising:

(a) at least one flat cathode layer having no holes for registration disposed therethrough, the cathode layer being formed of cathode foil and having a first perimeter of a first overall length, the cathode layer having at least a first tab projecting from the first perimeter at a first predetermined perimeter location;

(b) a plurality of flat anode layers formed of anode foil having no holes for registration disposed therethrough, the plurality of anode layers forming an anode sub-assembly, at least one of the plurality of anode layers being a first anode layer having a second perimeter of a second length and at least a second tab projecting from the second perimeter at a second predetermined perimeter location;

(c) at least one separator layer formed of separator material, the separator layer having a third perimeter of a third length;

(d) at least one separator envelope comprising upper and lower surfaces formed of separator material, the upper and lower surfaces of the separator envelope having fourth and fifth perimeters of fourth and fifth lengths, respectively;

(e) a case having sidewalls extending upwardly from a flat planar base to form an open end;

(f) a cover for sealing the open end of the case;

wherein the at least one cathode layer, the plurality of anode layers, and the at least one separator layer are vertically stacked between the upper and lower surfaces of the separator envelope and therewithin such that the at least one separator layer is disposed between the at least one cathode layer and the anode subassembly, the lengths of the first and second perimeters each being less than the respective lengths of the third, fourth or fifth perimeters, the fourth and fifth perimeters being joined together over at least a portion thereof to register and align the first tab in a first predetermined registration location and the second tab in a second predetermined registration location, the stacked at least one cathode layer, plurality of anode layers, at least one separator layer and separator envelope forming an electrode assembly, the electrode assembly being disposed within the open end of the case, the cover being sealingly disposed over the open end of the case.

121. The capacitor of claim 120, further comprising a second cathode layer formed of aluminum cathode foil and having a third perimeter, and a third separator layer formed of separator material, the second cathode layer having top and bottom surfaces and at least a third tab projecting from the third perimeter at a third predetermined perimeter location, the second cathode layer and the third separator layer being included within the separator envelope such that the third separator layer is disposed between the top surface of the anode sub-assembly and the bottom surface of the second cathode layer, the first tab and the third tab being vertically aligned such that the first predetermined registration location of the electrode assembly coincides vertically with the third predetermined registration location of the electrode assembly.

122. The capacitor of claim 120, further comprising a third separator layer formed of separator material and a second anode sub-assembly having top and bottom surfaces and comprising a plurality of anode layers formed of aluminum anode foil, at least one of the plurality of anode layers of the second anode sub-assembly being a fourth anode layer having a fourth perimeter, at least a fourth tab projecting from the fourth perimeter at a fourth predetermined perimeter location, the second anode sub-assembly and the third separator layer being included within the separator envelope such that the third separator layer is disposed beneath the first separator layer and the second anode sub-assembly is disposed between the first and third separator layers, the second tab and the fourth tab being vertically aligned such that the second predetermined registration location of the electrode assembly coincides vertically with the fourth predetermined registration location of the electrode assembly.