Patents Assigned to Maxwell Energy Products, Inc.
  • Patent number: 6233135
    Abstract: A single cell, multi-electrode high performance double layer capacitor includes an electrode stack adapted to fit within a capacitor container. The electrode stack comprises a plurality of electrodes, each comprising a current collector foil and a carbon cloth impregnated with a specified metal in direct physical contact with the current collector foil. The current collector foils of alternating electrodes are coupled to the first capacitor terminal, and the current collector foils of other alternating electrodes are coupled to the second capacitor terminal. A porous separator material is positioned between each electrode of the electrode stack, and has pores therein through which ions may readily pass while preventing adjacent electrodes from electrically contacting each other. The capacitor case comprises a first part and a second part fastenable to each other to form a sealed capacitor case which has a first capacitor terminal and a second capacitor terminal associated therewith.
    Type: Grant
    Filed: August 18, 1999
    Date of Patent: May 15, 2001
    Assignee: Maxwell Energy Products, Inc.
    Inventors: C. Joseph Farahmandi, John M. Dispennette, Edward Blank, Robert W. Crawford
  • Patent number: 6107808
    Abstract: A capacitor is made up of a housing; a first plurality of capacitors within the housing; a second plurality of capacitors within the housing; a first electrode coupled to a first terminal, with the first terminal being electrically contactable outside the housing; a second electrode coupled to a second terminal, with the second terminal being contactable outside the housing; a threshold circuit that compares performance of the first plurality of capacitors with performance of the second plurality of capacitors, detects an unbalance, and generates an output signal; and a signal output coupled to the threshold circuit, the signal output being accessible outside the housing. In another embodiment the capacitor has a housing; a first electrode contactable from outside the housing, a second electrode contactable from outside the housing, and an unbalance detection output contactable from outside the housing, wherein an unbalance detection signal indicative of a degree of unbalance.
    Type: Grant
    Filed: December 28, 1998
    Date of Patent: August 22, 2000
    Assignee: Maxwell Energy Products, Inc.
    Inventors: Gregg L. McKee, Frederick W. MacDougall
  • Patent number: 6094788
    Abstract: A method of making a double layer capacitior includes first and second flat stacks of electrodes adapted to be housed in a closeable two-part capacitor case which includes only a single electrolyte seal. Each electrode stack has a plurality of electrodes connected in parallel, with the electrodes of one stack being interleaved with the electrodes of the other stack to form an interleaved stack, and with the electrodes of each stack being electrically connected to respective capacitor terminals. A porous separator is positioned against the electrodes of one stack before interleaving to prevent electrical shorts between the electrodes. The electrodes are made by folding a compressible, low resistance, aluminum-impregnated carbon cloth, made from activated carbon fibers, around a current collector foil, with a tab of the foils of each electrode of each stack being connected in parallel and connected to the respective capacitor terminal.
    Type: Grant
    Filed: January 19, 1999
    Date of Patent: August 1, 2000
    Assignee: Maxwell Energy Products, Inc.
    Inventors: C. Joseph Farahmandi, John M. Dispennette, Edward Blank, Alan C. Kolb
  • Patent number: 6059847
    Abstract: A high performance double layer capacitor having an electric double layer formed in the interface between activated carbon and an electrolyte is disclosed. The high performance double layer capacitor includes a pair of aluminum impregnated carbon composite electrodes having an evenly distributed and continuous path of aluminum impregnated within an activated carbon fiber preform saturated with a high performance electrolytic solution. The high performance double layer capacitor is capable of delivering at least 5 Wh/kg of useful energy at power ratings of at least 600 W/kg.
    Type: Grant
    Filed: July 26, 1996
    Date of Patent: May 9, 2000
    Assignee: Maxwell Energy Products, Inc.
    Inventors: C. Joseph Farahmandi, John M. Dispennette
  • Patent number: 6008980
    Abstract: An integrated hermetically sealed feedthrough capacitor filter assembly is provided for the shielding and decoupling of a conductive terminal pin or lead of the type used, for example, in an implantable medical device such as a cardiac pacemaker or cardioverter defibrillator against passage of external interference signals, such as caused by digital cellular phones. The simplified feedthrough assembly described herein eliminates the traditional terminal pin subassembly. In this novel approach, the ceramic feedthrough capacitor itself forms a hermetic seal with a conductive pacemaker housing to which it is mounted by welding or brazing. The feedthrough capacitor is configured such that its internal electrodes are not exposed to body fluids, with capacitor electrode plate sets coupled respectively to a conductive ferrule, pin or housing (which may be grounded) and to the non-grounded, or active, terminal pin(s) by conductive adhesive, soldering, brazing, welding or the like.
    Type: Grant
    Filed: November 13, 1997
    Date of Patent: December 28, 1999
    Assignee: Maxwell Energy Products, Inc.
    Inventors: Robert A. Stevenson, Donald K. Haskell, Richard L. Brendel
  • Patent number: 5978204
    Abstract: An improved capacitor is provided particularly for use in electromagnetic interference (EMI) filter applications, for example, in an implantable medical device such as a heart pacemaker or defibrillator, to accommodate relatively high pulse currents. The capacitor comprises a plurality of active and ground electrode plates interleaved and embedded within a dielectric casing of ceramic or the like with each active and ground plate being defined by a closely spaced pair of conductive plate elements which significantly increase the total area of each electrode plate, and thereby correspondingly increase the current handling capacity of the capacitor.
    Type: Grant
    Filed: November 18, 1996
    Date of Patent: November 2, 1999
    Assignee: Maxwell Energy Products, Inc.
    Inventor: Robert A. Stevenson
  • Patent number: 5973906
    Abstract: An electromagnetic interference (EMI) filter capacitor assembly is provided for shielding and decoupling a conductive terminal pin or lead of the type used, for example, in an implantable medical device against passage of external interference signals. The EMI filter is constructed of relatively inexpensive ceramic chip capacitors which replace relatively expensive feedthrough capacitors as found in the prior art. The chip capacitors are mounted directly onto a hermetic feedthrough terminal in groups of two or more which vary in physical size, dielectric material and capacitance value so that they self-resonate at different frequencies. This "staggering" of resonant frequencies and direct installation at the hermetic terminal provides the EMI filter with sufficient broadband frequency attenuation. In one preferred form, multiple chip capacitor groupings are mounted onto a common base structure, with each capacitor grouping associated with a respective terminal pin.
    Type: Grant
    Filed: March 17, 1998
    Date of Patent: October 26, 1999
    Assignee: Maxwell Energy Products, Inc.
    Inventors: Robert A. Stevenson, Donald K. Haskell, Richard L. Brendel, Jason Woods, Mike Louder
  • Patent number: 5959829
    Abstract: An electromagnetic interference (EMI) filter capacitor assembly is provided for shielding and decoupling a conductive terminal pin or lead of the type used, for example, in an implantable medical device against passage of external interference signals. The EMI filter is constructed of relatively inexpensive ceramic chip capacitors which replace relatively expensive feedthrough capacitors as found in the prior art. The chip capacitors are mounted directly onto a hermetic feedthrough terminal in groups of two or more which vary in physical size, dielectric material and capacitance value so that they self-resonate at different frequencies. This "staggering" of resonant frequencies and direct installation at the hermetic terminal provides the EMI filter with sufficient broadband frequency attenuation. In one preferred form, multiple chip capacitor groupings are mounted onto a common base structure, with each capacitor grouping associated with a respective terminal pin.
    Type: Grant
    Filed: February 18, 1998
    Date of Patent: September 28, 1999
    Assignee: Maxwell Energy Products, Inc.
    Inventors: Robert A. Stevenson, Donald K. Haskell, Richard L. Brendel, Jason Woods, Mike Louder
  • Patent number: 5905627
    Abstract: An internally grounded ceramic feedthrough filter capacitor assembly provides for the shielding and decoupling of a conductive terminal pin or lead of the type used, for example, in an implantable medical device such as a cardiac pacemaker or cardioverter defibrillator against passage of external interference signals, such as those caused by digital cellular phones. The assembly includes a terminal pin subassembly having at least one terminal pin supported within a conductive ferrule by a hermetically sealed insulator structure. The ferrule is adapted for mounting onto a conductive substrate, such as a pacemaker housing, by welding or brazing to support the terminal pin subassembly for feedthrough passage to the housing interior. A ceramic feedthrough capacitor is mounted at an inboard side, with the capacitor electrode plate sets coupled respectively to a grounded lead and to the terminal pins(s) by conductive adhesive, soldering, brazing or the like.
    Type: Grant
    Filed: September 10, 1997
    Date of Patent: May 18, 1999
    Assignee: Maxwell Energy Products, Inc.
    Inventors: Richard L. Brendel, Robert A. Stevenson
  • Patent number: 5862035
    Abstract: A single cell, multi-electrode high performance double layer capacitor includes first and second flat stacks of electrodes adapted to be housed in a closeable two-part capacitor case which includes only a single electrolyte seal. Each electrode stack has a plurality of electrodes connected in parallel, with the electrodes of one stack being interleaved with the electrodes of the other stack to form an interleaved stack, and with the electrodes of each stack being electrically connected to respective capacitor terminals. A porous separator sleeve is inserted over the electrodes of one stack before interleaving to prevent electrical shorts between the electrodes. The electrodes are made by folding a compressible, low resistance, aluminum-impregnated carbon cloth, made from activated carbon fibers, around a current collector foil, with a tab of the foils of each electrode of each stack being connected in parallel and connected to the respective capacitor terminal.
    Type: Grant
    Filed: October 7, 1996
    Date of Patent: January 19, 1999
    Assignee: Maxwell Energy Products, Inc.
    Inventors: C. Joseph Farahmandi, John M. Dispennette, Edward Blank, Alan C. Kolb
  • Patent number: 5777428
    Abstract: A high performance double layer capacitor having an electric double layer formed in the interface between activated carbon and an electrolyte is disclosed. The high performance double layer capacitor includes a pair of aluminum impregnated carbon composite electrodes having an evenly distributed and continuous path of aluminum impregnated within an activated carbon fiber preform saturated with a high performance electrolytic solution. The high performance double layer capacitor is capable of delivering at least 5 Wh/kg of useful energy at power ratings of at least 600 W/kg.
    Type: Grant
    Filed: July 26, 1996
    Date of Patent: July 7, 1998
    Assignee: Maxwell Energy Products, Inc.
    Inventors: C. Joseph Farahmandi, John M. Dispennette