Patents Assigned to Maxwell Technologies
  • Patent number: 7227737
    Abstract: Electrodes of a double-layer capacitor are designed so that sub-capacitors formed at each electrode are stressed substantially equally at the rated voltage of the double-layer capacitor. In an exemplary embodiment, each electrode includes a current collector and an active electrode layer, such as a layer of activated carbon. The electrodes are held apart by a porous separator, and the assembly is immersed in an electrolyte. The thicknesses of the active electrode layers differ, resulting in asymmetrical construction of the capacitor. Different thicknesses cause the sub-capacitors to have different capacitances. When voltage is applied to the double-layer capacitor, the voltage is divided unequally between the unequal sub-capacitors. Properly selected thicknesses allow the voltages at the sub-capacitors to stress equally each sub-capacitor. The rated voltage of the double-layer capacitor can then be increased without overstressing the sub-capacitors.
    Type: Grant
    Filed: October 27, 2004
    Date of Patent: June 5, 2007
    Assignee: Maxwell Technologies, Inc.
    Inventors: Porter Mitchell, Xiaomei Xi, Linda Zhong, Bin Zou
  • Publication number: 20070122698
    Abstract: Dry process based energy storage device structures and methods for using a dry adhesive therein are disclosed.
    Type: Application
    Filed: October 14, 2005
    Publication date: May 31, 2007
    Applicant: Maxwell Technologies, Inc.
    Inventors: Porter Mitchell, Xiaomei Xi, Linda Zhong, Bin Zou
  • Publication number: 20070115006
    Abstract: Systems and methods for screening capacitors are disclosed. An exemplary method may comprise charging at least one capacitor for time t1 and then implementing the following operations. After charging time t1, comparing a charge state of the at least one capacitor to thresholds th1-low and th1-high for a capacitance screening operation. After waiting time t2, comparing the charge state of the at least one capacitor to a threshold th2 for an Equivalent Series Resistance (ESR) screening operation. After waiting time t3, comparing a change in the charge state of the at least one capacitor to a threshold th3 for a Leakage Current (LC) and Self-Discharge (SD) screening operation. The screening operations may be implemented manually by a user and/or automatically by the exemplary system described herein.
    Type: Application
    Filed: November 21, 2006
    Publication date: May 24, 2007
    Applicant: Maxwell Technologies, Inc.
    Inventors: Casey Anude, Bruce Brentlinger
  • Publication number: 20070098039
    Abstract: A transparent vacuum formed vessel 1 is filled with a liquid 3 at room temperature that will become a solid at freezing temperature and a low density float material 4. After freezing, the vessel is turned upside down so that upon thawing, the vivid colored float will move to the top of the vessel showing a thaw. The devise can be reused. The same concept can be used as a cooking aid by using a transparent sealed tubular 1 assembly inserted in the food with a solid cylinder 3 that will melt at some critical temperature allowing the low density float to rise to the top of the indicator visibly protruding from the food. More than one meltable cylinder, 3 & 8 and float, 4 & 5 may be used as a warning and ready indicator. Combinations of solid dense particulates and low density materials may also be used for color changing indicators. A permanent magnet attached to a float can be used to trigger an audible alarm, which can be incorporated in various cooking utensils to show cooking temperatures and times.
    Type: Application
    Filed: November 2, 2005
    Publication date: May 3, 2007
    Applicant: Maxwell Technologies, Inc.
    Inventor: Robert Parker
  • Patent number: 7203056
    Abstract: Thermal protection is provided in systems utilizing high-current double-layer capacitors. For example, in one implementation, an interconnection coupled to at least one double-layer capacitor that carries capacitor current to or from the at least one double-layer capacitor is functionally coupled to the at least one double-layer capacitor to reduce a temperature of the capacitor is provided.
    Type: Grant
    Filed: October 7, 2004
    Date of Patent: April 10, 2007
    Assignee: Maxwell Technologies, Inc.
    Inventor: Guy Thrap
  • Patent number: 7191516
    Abstract: A high reliability radiation shielding integrated circuit device comprising a plurality of package layers; a radiation shielding lid or base coupled to the plurality of package layers; wherein the circuit die are shielded from receiving an amount of radiation greater than the total dose tolerance of the circuit die. An integrated circuit device for use in high reliability applications. The integrated circuit device is designed to be highly reliable and protect integrated circuit die from failing or becoming unreliable due to radiation, mechanical forces, thermal exposure, or chemical contaminates.
    Type: Grant
    Filed: July 16, 2003
    Date of Patent: March 20, 2007
    Assignee: Maxwell Technologies, Inc.
    Inventor: Janet Patterson
  • Publication number: 20070053140
    Abstract: Electrical energy storage cells, for example, electrochemical double layer capacitor cells, are assembled into a module within an enclosure. The enclosure is built using modular construction so that it can be fitted to a variable number of cells. In exemplary embodiments, the enclosure may be flexibly formed to accommodate any number of cells.
    Type: Application
    Filed: November 15, 2005
    Publication date: March 8, 2007
    Applicant: Maxwell Technologies, Inc.
    Inventor: Ray Soliz
  • Publication number: 20070054559
    Abstract: A thermally fitted interconnect couples energy storage cells without the use of additional materials of fasteners. Variations of the interconnect can be used to facilitate fitting of multiple energy storage cell with multiple cell to cell spacings in a rapid and inexpensive manner.
    Type: Application
    Filed: November 14, 2005
    Publication date: March 8, 2007
    Applicant: Maxwell Technologies, Inc.
    Inventors: Guy Thrap, James Borkenhagen, Mark Wardas, Babak Maheronnaghsh
  • Patent number: 7180277
    Abstract: Electronic circuits couple energy storage devices, such as double layer capacitors or rechargeable battery cells, to a power supply output, thereby improving noise suppression and extending ride-through capability of the power supply. In a typical circuit, an energy storage device is coupled in series with a switch that controls the charging current into the energy storage device. The switch is controlled by a comparator that receives a signal related to the voltage level of the power supply. In some embodiments, the comparator also receives a feedback signal related to a charging current flowing into the energy storage device. The circuit is configured so that the switch limits the charging current to a predetermined current level, or does not allow the charging current to flow until the output voltage of the power supply reaches a predetermined voltage level.
    Type: Grant
    Filed: April 9, 2004
    Date of Patent: February 20, 2007
    Assignee: Maxwell Technologies, Inc.
    Inventor: Guy Thrap
  • Patent number: 7180726
    Abstract: A plurality of high capacitance capacitors are coupled to supply or accept large currents. Bus bars are welded to the capacitors to provide improved thermal performance as well as self-supporting rigidity to the geometrical structure formed by the capacitors and the bus bars.
    Type: Grant
    Filed: October 7, 2004
    Date of Patent: February 20, 2007
    Assignee: Maxwell Technologies, Inc.
    Inventor: Guy Thrap
  • Patent number: 7170260
    Abstract: A rapid charging circuit for charging a power module is disclosed. The power module includes one or more ultracapacitors. The power module is charged using an energy source connected to the power module. The charging circuit includes a control circuit adapted to maintain a constant power level at the power module during charging as the voltage level across the power module increases. The control circuit includes a pulse-width modulator and an inductor connected in series with the power module. The pulse-width modulator can control a charge level of the inductor. The charge level may correspond to a current level which is in accordance with a desired power level at the power module and an instantaneous voltage level across the power module. The inductor may be adapted to limit a current level through the power module to a predetermined peak level.
    Type: Grant
    Filed: June 30, 2003
    Date of Patent: January 30, 2007
    Assignee: Maxwell Technologies, Inc.
    Inventor: Guy C. Thrap
  • Patent number: 7170738
    Abstract: A high voltage capacitor design is provided that provides improved performance. The high voltage capacitor includes a stack of mechanically joined capacitor cells, which in one variant utilize a separator formed of two layers of paper. In one version, the high voltage capacitor may be used as a capacitative voltage divider.
    Type: Grant
    Filed: December 17, 2004
    Date of Patent: January 30, 2007
    Assignee: Maxwell Technologies, Inc.
    Inventors: Cedric Scheidegger, Pocol Sorin, Meyer Gerald
  • Publication number: 20070008678
    Abstract: Porous separator is sandwiched between electrode films with attached current collector foil to obtain an electrode sheet. The electrode sheet is formed into a jellyroll for use in a double layer capacitor. The jellyroll is inserted into a can through an open end to rest against the can's bottom. A collector plate is pressed against the jellyroll, crunching current collector foil protruding from each end of the jellyroll. The bottom and the collector plate include indentations of reduced thickness. Laser is applied to the indentations to weld the foil on each end of the jellyroll to the bottom or collector plate. The laser application pattern, for example, a zigzag pattern, results in the total length of laser welds along each indentation being considerably longer than the length of the indentation, reducing contact resistance between (1) the foil and the bottom, and (2) the foil and the current collector.
    Type: Application
    Filed: December 8, 2005
    Publication date: January 11, 2007
    Applicant: Maxwell Technologies, Inc.
    Inventors: Alex Fresard, Robert Crawford
  • Publication number: 20070008677
    Abstract: Particles of active electrode material are made by blending and fibrillizing (i.e., fibrillating) a mixture of activated carbon, conductive carbon, and fibrillizable binder. In selected embodiments, chloride level in the activated carbon is relatively low, a small amount of conductive carbon with low impurity levels and high conductivity is used, and the binder is inert. For example, chloride content of the activated carbon is below 50 ppm, and total impurities in the conductive carbon are below 120 ppm. The mixture may include about 10% of PTFE and 0.5% or less of conductive carbon. Blending and fibrillization may be performed without solvents. The fibrillized particles are dried, blended again to reduce clumping, and used to make active electrode material film. The film is attached to a current collector to obtain an electrode for use in various electrical devices, including double layer capacitors. The electrode increases breakdown voltage of the capacitor electrolyte.
    Type: Application
    Filed: July 8, 2005
    Publication date: January 11, 2007
    Applicant: Maxwell Technologies, Inc.
    Inventors: Linda Zhong, Xiaomei Xi
  • Patent number: 7148084
    Abstract: A radiation shielded and packaged integrated circuit semiconductor device includes a lid secured to a base to enclose an integrated circuit die within, wherein the lid and the base are each constructed from a high Z material to prevent radiation from penetrating therethrough. Another embodiment includes a die attach slug constructed from a high Z material disposed between the integrated circuit die and the base, in combination with a high Z material lid to substantially block incident radiation.
    Type: Grant
    Filed: April 9, 2004
    Date of Patent: December 12, 2006
    Assignee: Maxwell Technologies, Inc.
    Inventors: David J. Strobel, David R. Czajkowski
  • Patent number: 7147674
    Abstract: Active electrode material, such as fibrillized blend of activated carbon, polymer, and conductive carbon, is pretreated by immersion in a sealing coating. After the active electrode material is dried, the coating seals micropores of the activated carbon or another porous material, thus preventing exposure of water molecules or other impurities trapped in the micropores to outside agents. At the same time, the sealing coating does not seal most mesapores of the porous material, allowing exposure of the mesapores' surface area to the outside agents. The pretreated active electrode material is used for making electrodes or electrode assemblies of electrical energy storage devices. For example, the electrodes may be immersed in an electrolyte to construct electrochemical double layer capacitors. Pretreatment with the sealing coating reduces the number of water molecules interacting with the electrolyte, enhancing the breakdown voltage of the capacitors.
    Type: Grant
    Filed: March 23, 2005
    Date of Patent: December 12, 2006
    Assignee: Maxwell Technologies, Inc.
    Inventors: Linda Zhong, Xiaomei Xi, Bin Zou
  • Publication number: 20060246343
    Abstract: A dry particle packaging system and method for making is disclosed.
    Type: Application
    Filed: October 14, 2005
    Publication date: November 2, 2006
    Applicant: Maxwell Technologies, Inc.
    Inventors: Porter Mitchell, Xiaomei Xi, Bin Zou, Linda Zhong
  • Publication number: 20060244427
    Abstract: A power module includes double layer capacitors, a voltage booster, a charging circuit, and a switching assembly. In discharging mode, the switching assembly connects the voltage booster to the output of the power module. The voltage booster enhances the voltage of the cells as needed for operation of a load at the output of the module. In charging mode, the switching assembly connects the charging circuit to the output of the module to receive electric energy from an external charger connected to the output of the module. The charging circuit converts the received energy into energy suitable for recharging the cells. In end-of-cycle discharging mode, the switching assembly connects the voltage booster to the charging circuit, causing these devices to loop into each other. Inefficiencies in the voltage booster and the charging circuit dissipate the energy in the cells, rendering the battery fail-safe.
    Type: Application
    Filed: April 28, 2005
    Publication date: November 2, 2006
    Applicant: Maxwell Technologies, Inc.
    Inventor: Guy Thrap
  • Patent number: 7116545
    Abstract: A long life double layer capacitor and method of making the same including a case and a first terminal with an electrically insulating hermitic seal interposed between the first terminal and the case. A first current collector foil is electrically coupled to an interior portion of the first terminal and a first electrode comprising carbon which is juxtaposed against the first current collector foil. A porous separator is then juxtaposed against the first electrode comprising carbon and separating the first electrode from a second electrode comprising carbon. A second current collector foil is juxtaposed against a side of the second electrode and is electrically coupled to the second terminal.
    Type: Grant
    Filed: March 9, 2005
    Date of Patent: October 3, 2006
    Assignee: Maxwell Technologies, Inc.
    Inventors: C. Joseph Farahmandi, John M. Dispennette, Edward Blank, Robert W. Crawford, Chenniah Nanjundiah
  • Publication number: 20060203429
    Abstract: A thermally fitted interconnect couples energy storage cells without the use of additional materials of fasteners. Variations of the interconnect can be used to facilitate fitting of multiple energy storage cell with multiple cell to cell spacings in a rapid and inexpensive manner.
    Type: Application
    Filed: September 2, 2005
    Publication date: September 14, 2006
    Applicant: Maxwell Technologies, Inc.
    Inventors: Guy Thrap, James Borkenhagen, Mark Wardas