Abstract:
An electric double-layer ultracapacitor configured to maintain desired operation at an operating voltage of three volts, where the capacitor includes a housing component, a first and a second current collector, a positive and a negative electrode electrically coupled to one of the first and second current collectors, and a separator positioned between the positive and the negative electrode. The capacitor may also include an electrolyte in ionic contact with the electrodes and the separator, the electrolyte having acetonitrile and a quaternary ammonium salt with a molarity of less than one.
Abstract:
This disclosure provides systems, methods and apparatus for a battery system. The battery system includes an enclosure, a battery disposed within the enclosure; and at least one ultracapacitor. The ultracapacitor is disposed within the enclosure and coupled to the battery to provide electrical energy via battery terminals. The enclosure conforms to a standard form factor for a battery that comprises one or more conventional storage cells without an ultracapacitor.
Abstract:
This disclosure provides systems, methods and apparatus for a combined battery/capacitor energy storage device. In one aspect, the device includes a housing with an integrated battery housing portion, a capacitor housing portion, and a housing lid. A plurality of battery electrodes and electrolyte are contained directly within the integrated battery housing portion and are configured to form an integrated battery within the integrated battery housing portion. The capacitor is connected in parallel with the battery and contained within the capacitor housing portion. A first device terminal and a second device terminal extending through the housing.
Abstract:
This disclosure provides systems, methods and apparatus for a combined battery/capacitor energy storage device. The device includes a first device terminal, a second device terminal, a battery connected between the first terminal and the second terminal, and a capacitor connected in parallel with the battery. In one aspect, a rectifier is connected between the first terminal and the capacitor, the rectifier configured to allow substantially unidirectional current flow from the first terminal to the capacitor. In another aspect, a switch is between the capacitor and the first terminal. In another aspect, a current limiter extends between the first terminal and the capacitor.
Abstract:
An energy storage system is described for use in, for example, electronics systems such as a bank of computers. The disclosed energy storage systems allows the use of an efficient energy source, such as ultracapacitors, while providing a desired voltage level for an extended period of time. One embodiment of the energy storage system provides power to a load. The system includes a power module including at least one ultracapacitor adapted to store and discharge energy. The power module provides an output voltage as the ultracapacitor discharges energy. The system also includes a voltage regulator for boosting the output voltage of the power module. The voltage regulator may include a voltage converter. The voltage converter may be adapted to boost the output voltage when the output voltage falls below a predetermined threshold. The voltage converter may include a plurality of interleaving inductor circuits, each of the circuits including a switch and an inductor. The switches are adapted to be alternatingly closed and opened, thereby alternatingly storing energy in the inductors and discharging energy to the load.
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. The control circuit may be adapted to provide a current level through the power module greater than a current level from said energy source during at least a portion of a charging period.
Abstract:
A charge balancing circuit is configured to provide charge balancing for a bank of series connected charge storage devices. One embodiment of the charge balancing circuit comprises a voltage divider, an amplifier, and a negative feedback resistor connected between every two capacitors. The circuit is configured to monitor the voltage in each of the capacitors and, if the voltage in one of the capacitors is higher than the other, the circuit transfers energy from the higher charged capacitor to the lower charged capacitor until the capacitors are balanced. A current limiting resistor can be included for limiting the output current of the amplifier to a safe value and for providing feedback information regarding the health of the capacitor. An additional gain stage can also be included for increasing the output current of the amplifier for banks of large charge storage devices. The circuit can be used in bi-polar applications.
Abstract:
A charge balancing circuit is disclosed that is configured to provide charge balancing for a bank of series connected charge storage devices such as capacitors. One embodiment of the charge balancing circuit comprises a voltage divider, an operational amplifier, and a negative feedback resistor connected between every two capacitors. The circuit is configured to monitor the voltage in each of the capacitors and, if the voltage in one of the capacitors is higher than the other, the circuit transfers energy from the higher charged capacitor to the lower charged capacitor until the capacitors are balanced. A current limiting resistor can be included for limiting the output current of the operational amplifier to a safe value and for providing feedback information regarding the health of the capacitor. An additional gain stage can also be included for increasing the output current of the operational amplifier for banks of large charge storage devices such as capacitors.
Abstract:
A method of making an electrode structure, the electrode structure and a double layer capacitor including the electrode structure, the method comprising the steps of: forming a plurality of electrodes, each having a current collector plate, a primary coating formed on each side of the collector plate, the primary coating including conducting carbon powder and a binder, and a secondary coating formed on each primary coating, the secondary coating including activated carbon powder, a solvent and a binder; positioning a respective separator between each electrodes while stacking the electrodes such that the respective separator is juxtaposed against respective secondary coatings of adjacent electrodes that electrically insulates the adjacent electrodes, whereby forming an electrode stack; and rolling the electrode stack into a cylindrical electrode structure.