Abstract: Electrodes are constructed with pressure-bonding techniques that simplify alignment of various electrode components during lamination. In an exemplary embodiment, a current collector is made from aluminum foil that has been roughed or pitted on both surfaces. The surfaces of the current collector can be further treated to enhance adhesion properties of these surfaces. Layers of film that include active electrode material, such as activated carbon particles, are fabricated using non-lubricated techniques. Each film is coated on one side with an adhesive binder solution, such as a thermoplastic solution. The adhesive binder is dried, and the films are laminated to the current collector using a calender with heated rollers. The resulting electrode product is processed to shape electrodes, which can then be used in electrical energy storage devices, including double layer capacitors.
Type:
Grant
Filed:
February 24, 2009
Date of Patent:
December 14, 2010
Assignee:
Maxwell Technologies, Inc.
Inventors:
Porter Mitchell, Xiaomei Xi, Linda Zhong, Bin Zou
Abstract: An active voltage management device and a method for actively managing a voltage level of an energy storage device are provided. The active voltage management device comprises: a pair of input terminals adapted to be connected to the energy storage device; a reverse polarity protection circuit coupled to the pair of input terminals; a voltage comparator circuit adapted to compare a second voltage associated with the voltage level of the energy storage device to a reference voltage and to provide an output based upon the comparison of the second voltage to the reference voltage; and a transistor adapted to operate in a linear mode to dissipate energy from the energy storage device at a substantially constant current level, wherein output of the voltage comparator circuit is adapted to activate the transistor when the second voltage is greater than or equal to the reference voltage.
Type:
Grant
Filed:
November 19, 2007
Date of Patent:
October 19, 2010
Assignee:
Maxwell Technologies, Inc.
Inventors:
Dragan Nebrigic, Jeffrey Johnstone, Vlastislav Haman, Hung Q. Ha
Abstract: Particles of active electrode material are made by blending mixing a mixture of activated carbon and binder. In selected implementations, sulfur level in the activated carbon is relatively low and the binder is inert. For example, sulfur content of the activated carbon and the resultant mixture is below 300 ppm and in other implementations, below 50 ppm. The electrode material may be attached to a current collector to obtain an electrode for use in various electrical devices, including a double layer capacitor. The electrode decreases current leakage of the capacitor.
Type:
Grant
Filed:
February 27, 2008
Date of Patent:
October 12, 2010
Assignee:
Maxwell Technologies, Inc.
Inventors:
Linda Zhong, Xiaomei Xi, Porter Mitchell
Abstract: A coated electrode is provided for use in energy storage devices. The coated electrode comprises a dry fibrillized polymer that is fibrillized with no processing additives.
Type:
Grant
Filed:
April 2, 2004
Date of Patent:
September 7, 2010
Assignee:
Maxwell Technologies, Inc.
Inventors:
Porter Mitchell, Linda Zhong, Vincent Hermann, Chenniah Nanjundiah
Abstract: An inexpensive and reliable dry process based capacitor and method for making a self-supporting dry electrode film for use therein is disclosed. Also disclosed is an exemplary process for manufacturing an electrode for use in an energy storage device product, the process comprising: supplying dry carbon particles; supplying dry binder; dry mixing the dry carbon particles and dry binder; and dry fibrillizing the dry binder to create a matrix within which to support the dry carbon particles as dry material.
Type:
Grant
Filed:
January 31, 2008
Date of Patent:
September 7, 2010
Assignee:
Maxwell Technologies, Inc.
Inventors:
Linda Zhong, Xiaomei Xi, Porter Mitchell, Bin Zou
Abstract: A high reliability radiation shielding integrated circuit apparatus 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 of tolerance of the circuit die. In one embodiment, an integrated circuit apparatus for use in high reliability applications is disclosed. The integrated circuit apparatus 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.
Abstract: Composite electrodes are constructed with pressure-bonding techniques instead of an adhesive. A current collector is made from aluminum foil roughed on both surfaces. The surfaces of the collector can be treated to enhance adhesion to the surfaces. Layers of film that includes active electrode material, such as activated carbon, are fabricated and pressure-bonded to the current collector using a calender with heated rollers. The resulting composite sheet is then processed to shape electrodes, which can be used in electrical energy storage devices, including double layer capacitors.
Type:
Grant
Filed:
July 17, 2006
Date of Patent:
May 25, 2010
Assignee:
Maxwell Technologies, Inc.
Inventors:
Xiaomei Xi, Linda Zhong, Porter Mitchell
Abstract: A coated electrode is provided for use in energy storage devices. The coated electrode comprises a dry fibrillized polymer that is fibrillized with no processing additives.
Type:
Application
Filed:
November 17, 2009
Publication date:
May 13, 2010
Applicant:
MAXWELL TECHNOLOGIES, INC.
Inventors:
Linda Zhong, Porter Mitchell, Vincent Hermann, Chenniah Nanjundiah
Abstract: An energy storage device electrode product is provided. The product comprises: at least one current collector and at least one electrode film disposed adjacent to the at least one current collector. The at least one current collector comprises a plurality of voids extending through a thickness of the current collector, wherein the plurality of voids allow electrolyte to flow through the thickness of the current collector. The plurality of voids extending through the current collector is formed without reducing a surface area of a conductive material of the current collector disposed adjacent to the electrode by more than about fifty percent. A method of producing an electrode product and a double layer capacitor product are also disclosed.
Abstract: Particles of active electrode material are made by blending or mixing a mixture of activated carbon, optional conductive carbon, and binder. In selected implementations, iron 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 one example, iron content of the activated carbon and the resultant mixture is below 20 ppm. The electrode material may be attached to a current collector to obtain an electrode for use in various electrical devices, including a double layer capacitor. The electrode decreases current leakage of the capacitor.
Type:
Application
Filed:
February 27, 2008
Publication date:
May 6, 2010
Applicant:
MAXWELL TECHNOLOGIES, INC.
Inventors:
Linda Zhong, Xiaomei Xi, Porter Mitchell
Abstract: Particles of active electrode material are made by blending mixing a mixture of activated carbon and binder. In selected implementations, sulfur level in the activated carbon is relatively low and the binder is inert. For example, sulfur content of the activated carbon and the resultant mixture is below 300 ppm and in other implementations, below 50 ppm. The electrode material may be attached to a current collector to obtain an electrode for use in various electrical devices, including a double layer capacitor. The electrode decreases current leakage of the capacitor.
Type:
Application
Filed:
February 27, 2008
Publication date:
April 22, 2010
Applicant:
MAXWELL TECHNOLOGIES, INC.
Inventors:
Linda Zhong, Xiaomei Xi, Porter Mitchell
Abstract: A high reliability radiation shielding integrated circuit apparatus 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 of tolerance of the circuit die. In one embodiment, an integrated circuit apparatus for use in high reliability applications is disclosed. The integrated circuit apparatus 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.
Abstract: An energy storage apparatus and article of manufacture is disclosed. In one embodiment, the energy storage apparatus comprises a jelly roll, having a first and second sheet and a first and second separator member, and at least one terminal element. In another embodiment, an article of manufacture comprising forming a cylindrical housing and stamping a longitudinal indentation on an exterior surface of the cylindrical housing is disclosed. In one alternate embodiment, the longitudinal indentation is adapted to slowly fracture under pressure exerted on an interior surface of the cylindrical housing, thereby preventing catastrophic failure, such as for example an explosion.
Abstract: Power supply voltage of a PCI or a similar communication bus interface is separated from one or more other power supply voltages on a backplane, on boards insertable into the backplane, and on the bus interface components of the boards. The power supply of the bus interface (VIO) is provided to cold spare boards inserted into the backplane, while the other voltages are not provided to the cold spare boards. Availability of the VIO on the cold spare boards prevents the VIO clamping diodes on the PCI I/O lines from grounding the PCI bus. Cold spare capability is thus provided to systems with PCI and similar communication buses.
Abstract: State of a high voltage capacitor is monitored to detect partial discharge within the capacitor and approaching end-of-life of the capacitor. Partial discharge may be detected through an increased capacitance of the capacitor, and the resulting increase in the alternating current through the capacitor. Partial discharge may also be detected by presence of high frequency components in the current. Moreover, partial discharge may be detected through an increase in the internal pressure of the capacitor. When partial discharge is detected, a warning is generated, and the capacitor may be replaced in response to the warning. Periodic or random checks of the capacitor state, as indicated by the current or pressure, may also be performed. Warnings may be, for example, visual and/or audio, and may be transmitted to remote locations by radio frequency, infrared signals, or via power lines.
Abstract: Particles of active electrode material are made by blending or mixing a mixture of activated carbon, optional conductive carbon, and binder. In selected implementations, the activated carbon particles have between about 70 and 98 percent microporous activated carbon particles and between about 2 and 30 percent mesaporous activated carbon particles by weight. Optionally, a small amount of conductive particles, such as conductive carbon particles may be used. In one implementation, the binder is inert. The electrode material may be attached to a current collector to obtain an electrode for use in various energy storage devices, including a double layer capacitor.
Abstract: Particles of active electrode material are made by blending or mixing a mixture of activated carbon, optional conductive carbon, and binder. In selected implementations, binder content in the electrode material is relatively low, typically the binder content of the mixture being between about 3 percent and about 10 percent by weight. The electrode material may be attached to a current collector to obtain an electrode for use in various electrical devices, including a double layer capacitor. The composition of the mixture increases the energy density and the integrity of the electrode.
Type:
Application
Filed:
June 30, 2009
Publication date:
December 31, 2009
Applicant:
MAXWELL TECHNOLOGIES, INC.
Inventors:
Linda Zhong, Xiaomei Xi, Porter Mitchell