30942 results about "Charge and discharge" patented technology

A method of producing a diode drive current in an oximeter includes sensing at least a part of a current passing through the diode and converting the sensed current to a sensed voltage, inputting the sensed voltage to a feedback amplifier for stabilizing the current passing through the diode, and eliminating an offset voltage across inputs of the feedback amplifier. A pulse oximeter includes a diode for emitting light flashes, a feedback amplifier having inputs, a feedback capacitor, and an output, the feedback amplifier stabilizing a current passing through the diode, a nulling amplifier having inputs, a nulling capacitor, and an output, the nulling amplifier charging and discharging the feedback capacitor until the inputs of the feedback amplifier are at a same voltage. The operation may include synchronizing an elimination of input offset voltages of the feedback and nulling amplifiers with on or off state of diode current.

A cordless instrument (20, 40) detachable from a charger (10, 30, 31) is attached to the charger (10, 30, 31), and is charged. A first storage part (12, 33) chargeable from a direct current source (11, 32) included in the charger (10, 30, 31), a first charge and discharge control circuit (13, 50) to control charge and discharge of the first storage part (12, 33), a second storage part (21, 43) included in the cordless instrument (20, 40), and a second charge and discharge control circuit (22, 45) to control charge and discharge of the second storage part (21, 43) are provided. Further, a third storage part (28) chargeable from the direct current source (11, 32) may be provided. Also to the cordless instrument (20, 40), a fourth storage part (44) may be provided. Upon attaching the cordless instrument, the second storage part (21, 43) is charged at least from the first storage part (12, 33). In comparison with charging time to conventional secondary batteries, it is capable of rapid charge, long life use, resulting in such merits as to realize the compact size of a charger and low cost.

A nano graphene-enhanced particulate for use as a lithium-ion battery anode active material, wherein the particulate is formed of a single sheet of graphene or a plurality of graphene sheets and a plurality of fine anode active material particles with a size smaller than 10 μm. The graphene sheets and the particles are mutually bonded or agglomerated into the particulate with at least a graphene sheet embracing the anode active material particles. The amount of graphene is at least 0.01% by weight and the amount of the anode active material is at least 0.1% by weight, all based on the total weight of the particulate. A lithium-ion battery having an anode containing these graphene-enhanced particulates exhibits a stable charge and discharge cycling response, a high specific capacity per unit mass, a high first-cycle efficiency, a high capacity per electrode volume, and a long cycle life.

In an exemplary embodiment, a battery conditioning system monitors battery conditioning and includes a memory for storing data based thereon; for example, data may be stored representative of available battery capacity as measured during a deep discharge cycle. With a microprocessor monitoring battery operation of a portable unit, a measure of remaining battery capacity can be calculated and displayed. Where the microprocessor and battery conditioning system memory are permanently secured to the battery so as to receive operating power therefrom during storage and handling, the performance of a given battery in actual use can be accurately judged since the battery system can itself maintain a count of accumulated hours of use and other relevant parameters. In the case of a nonportable conditioning system, two-way communication may be established with a memory associated with the portable unit so that the portable unit can transmit to the conditioning system information concerning battery parameters (e.g. rated battery capacity) and/or battery usage (e.g. numbers of shallow discharge and recharge cycles), and after a conditioning operation, the conditioning system can transmit to the portable unit a measured value of battery capacity, for example. A battery pack having memory stores battery history and identifying data to be retrieved by a portable battery powered device. Battery status information may be utilized in conjunction with characteristic battery history data in order to optimize charging and discharging functions and to maximize the useful life of a battery pack.

A method of providing closed-loop control of power flowing into and out of an energy storage system (ESS), wherein the ESS comprises a battery is provided. The method may be implemented as a computer control algorithm for determining the charge and discharge limits for the ESS in a hybrid electric vehicle (HEV), wherein the ESS comprises a battery pack or array. The method comprises determining charge and discharge power limits during each of a plurality of control loops, comparing these limits during each of the plurality of control loops, and providing a charge power limit output and a discharge power limit output for use in a subsequent control loop which are based upon the charge power limit and the discharge power limit. The charge power limit output and discharge power limit output are set equal to the discharge power limit and charge power limit, respectively, when the discharge power limit is greater than the charge power limit; and are selected from the group consisting of the charge power limit, the discharge power limit and zero when the discharge power limit is less than or equal to the charge power limit.

A dynamic memory circuit in which the inherent bipolar transistor effect within a floating body transistor is utilized to store an information bit. A floating body of a storage transistor stores an information bit in the form of an electric charge. The floating body is charged and discharged via an access transistor during data write operations. The inherent bipolar transistor resident within the floating body transistor increases the effective capacitance of the floating body which acts as the storage node, and thereby enhances the magnitude of the discharge current which represents the stored information bit during read operations.

A Distributed Energy Storage Control System (DESCS) comprised of one or a plurality of identical BMS (Battery Management System) battery unit (40), series-parallel system controller (60) and DESCS main controller (70). Each BMS battery unit (40) including a smart battery unit (10), a discharge bypass path control switch (43), a super capacitor (45), a charge bypass load (46) and charge bypass path control switch (44). This DESCS system substantially promotes the energy efficiency of battery, provides a large scale and complicated energy storage system with on-line repair or replacement of batteries, proceeds charge/discharge task uninterrupted during maintenance, and possesses high maintainability.

Electrochemical cells, and more specifically, rechargeable batteries comprising lithium anodes for use in water and/or air environments, as well as non-aqueous and non-air environments, are presented. In one embodiment, an electrochemical cell includes an anode comprising lithium and a multi-layered structure positioned between the anode and an electrolyte of the cell. A multi-layered structure can include at least a first single-ion conductive material layer (e.g., a lithiated metal layer), and at least a first polymeric layer positioned between the anode and the single-ion conductive material. The invention also can provide an electrode stabilization layer positioned within the electrode, i.e., between one portion and another portion of an electrode, to control depletion and re-plating of electrode material upon charge and discharge of a battery. Advantageously, electrochemical cells comprising combinations of structures described herein are not only compatible with environments that are typically unsuitable for lithium, but the cells may be also capable of displaying long cycle life, high lithium cycling efficiency, and high energy density.

In order to charge and discharge parasitic capacitance of a source signal line sufficiently and program a predetermined current value into a pixel transistor, it is necessary to output a relatively large current from the source driver circuit.

However, if such a large current is passed through the source signal line, the value of this current is programmed into the pixel, causing a larger than desired current to flow through an EL element 15.

For example, if a 10 times larger current is used for programming, a 10 times larger current flows through the EL element 15, and thus the EL element 15 illuminates 10 times more brightly. To obtain predetermined emission brightness, the time during which the current flows through the EL element can be reduced to 1/10 of one frame (1 F). This way, the parasitic capacitance of the source signal line can be charged and discharged sufficiently and the predetermined emission brightness can be obtained.

PCT No. PCT/NZ97/00053 Sec. 371 Date Nov. 3, 1998 Sec. 102(e) Date Nov. 3, 1998 PCT Filed May 2, 1997 PCT Pub. No. WO97/42695 PCT Pub. Date Nov. 13, 1997Loosely coupled inductive power for charging batteries is rectified from a first power pickup winding and the resulting current source is connected to a battery unit. Each current source is controlled by shorting a second resonant winding. Battery banks may be charged using multiple isolated position-tolerant pickups independently controlled according to the condition of the connected battery unit and by overall commands communicated over an isolated link. The battery unit may be a single cell. In a self-stabilizing bank or monoblock a primary inductive conductor is energized using all the cells, individual cells are separately monitored by control means and any below-average cell can be individually charged from the inductive conductor, thus correcting between-cell variations. The charge in all cells within a bank can be held within 30% to 70% of full charge and prevented from drifting towards full or empty during repetitive charge and discharge times.

A system and method for digital management and control of power conversion from battery cells. The system utilizes a power management and conversion module that uses a CPU to maintain a high power conversion efficiency over a wide range of loads and to manage charge and discharge operation of the battery cells. The power management and conversion module includes the CPU, a current sense unit, a charge/discharge unit, a DC-to-DC conversion unit, a battery protection unit, a fuel gauge and an internal DC regulation unit. Through intelligent power conversion and charge/discharge operations, a given battery type is given the ability to emulate other battery types by conversion of the output voltage of the battery and adaptation of the charging scheme to suit the battery.

A power converter includes a DC to AC inverter that is connected to a neutral node formed between first and second capacitors connected across two DC supply lines. The inverter is operated to selectively couple the DC supply lines and the neutral node to an output terminal thereby producing an alternating voltage waveform formed by a sequence of output pulses having positive, zero and negative voltage levels. To compensate for a voltage imbalance across the capacitors, an imbalance compensation coefficient is derived from the difference in voltages across the first and second capacitors and from the direction of current between the neutral node and the inverter. The imbalance compensation coefficient is employed to adjust the width of the output pulses so as to charge and discharge the capacitors to correct the imbalance.

A battery management unit and system for managing the state of charge of cells or batteries (B1-B10). Each battery management unit (1) measures cell or battery terminal voltage and provides this information to a central controller (3) via a communication medium (2). Each battery management unit (1) monitors a plurality of batteries (B1-B10) and can selectively charge a selected battery (B1-B10) via a charger (7) and switch circuit (8, 17) or can selectively discharge a selected battery (B1-B10) via a load (10) and switch circuit (8, 17) under the control of a controller (6). The controller (6) may control charging and discharging in accordance with measurements from voltage sensors (15a-j) or may convey information from a voltage sensors (15a-15j) to the central controller (3) and receive charging and discharging commands from the central controller (3). Charging and discharging is controlled to maintain all batteries within a desired state of charge ranged. The central controller (3) may selectively connect a main charger (20) or generator (21) to a bank of batteries associated with a battery management unit (1).

Positive electrode active materials are described that have a very high specific discharge capacity upon cycling at room temperature and at a moderate discharge rate. Some materials of interest have the formula Li_1+xNi_αMn_βCO_γO₂, where x ranges from about 0.05 to about 0.25, α ranges from about 0.1 to about 0.4, β ranges from about 0.4 to about 0.65, and γ ranges from about 0.05 to about 0.3. The materials can be coated with a metal fluoride to improve the performance of the materials especially upon cycling. Also, the coated materials can exhibit a very significant decrease in the irreversible capacity lose upon the first charge and discharge of the cell. Methods for producing these materials include, for example, a co-precipitation approach involving metal hydroxides and sol-gel approaches.

The invention discloses a carbon/silicon/carbon nano composite structure cathode material and a preparation method thereof, belonging to the technical field of electrochemical power supply technologies. The cathode material consists of a carbon-based conductive substrate, nano silicon and a nano carbon coating layer, wherein the nano silicon is uniformly distributed on the carbon-based conductive substrate; the nano carbon coating layer is arranged on the surface of the nano silicon; the carbon-based conductive substrate is porous carbon, a carbon nanotube or graphene; the nano silicon exists in the state of nanoparticles or nano films; the weight percentage of the nano silicon in the cathode material is 10-90 percent; and the thickness of the nano carbon coating layer is 0.1-10 nanometers. The preparation method comprises the following steps of: depositing nano silicon on the carbon substrate in a reaction space in oxygen-free atmosphere by adopting a chemical vapor deposition process; and coating nano carbon on the surface of the nano silicon by adopting the chemical vapor deposition process. In the obtained carbon/silicon/carbon composite cathode material, the volume change of a silicon electrode material is controlled effectively in the charging and discharging processes, the electrode structure is kept complete, the circulation volume is large, the circulation service life is long, and the electrochemical performance is high.

A method of providing power to an electronic device in an energy-efficient manner includes transitioning between power states corresponding to charging and discharging a battery. The state of charge of the battery is detected. Upon detecting a high threshold state of charge, an external power source such as an AC-to-DC adapter is disabled, and the battery to provides primary power to the electronic device. Upon a low threshold state of charge, the AC-to-DC adapter is controlled to provide a high current output to charge the battery and provide primary power to the electronic device. The power states, when cycled over time based on the state of the battery, provide for an energy-efficient method of powering the electronic device.

A circuit for rendering an energy storage device parallelable comprised of an energy storage device connected to a power adapter that converts the potential of the energy storage device into a potential that follows a predetermined function of the state of charge of the energy storage device. When multiple assemblies are paralleled, they may be charged and discharged as a whole with individual storage devices maintaining equal states of charge. The energy storage devices can be batteries with different cell counts, configurations, and energy discharge profiles. In some cases, the power adapters are comprised of DC to DC converters and system controllers that are used to translate each battery's energy discharge profile into a user-determined energy discharge profile that is a predictable function of the battery's state of charge and independent of temperature or other external conditions.

A battery controller for charging and discharging a plurality of batteries is disclosed. The battery controller has a plurality of direct current to direct current (DC to DC) converters connected to each other in series. Each battery of a plurality of batteries is electrically connectable to a respective DC to DC converter. A co-ordinator connected to each of the plurality of DC to DC converters controls charging and discharging of the battery electrically connected to the respective converter. The co-ordinator can also control charging and discharging of any one of the batteries to ensure that the battery retains sufficient electrical capacity, and, to increase the longevity of the respective batteries. Because each battery is electrically connected to a respective DC to DC converter, the energy from one battery can be used to charge another battery in order to monitor battery characteristics including energy capacity of each battery. Each of the DC to DC converters is selected to operate preferably below 30 volts while the total voltage of the entire battery system can be much more than 30 volts depending on the number of DC to DC converters placed in series.

Provided are a porous anode active material, a method of preparing the same, and an anode and a lithium battery employing the same. The porous anode active material includes fine particles of metallic substance capable of forming a lithium alloy; a crystalline carboneous substance; and a porous carboneous material coating and attaching to the fine particles of metallic substance and the crystalline carboneous substance, the porous anode active material having pores exhibiting a bimodal size distribution with two pore diameter peaks as measured by a Barrett-Joyner-Halenda (BJH) pore size distribution from a nitrogen adsorption. The porous anode active material has the pores having a bimodal size distribution, and thus may efficiently remove a stress occurring due to a difference of expansion between a carboneous material and a metallic active material during charging and discharging. Further, the anode electrode and the lithium battery comprising the anode active material have excellent charge/discharge characteristics.

Edge rates for output driver transistors are increased for slower conditions such as caused by supply-voltage, temperature, and process variations. The edge rates are increased by increasing charging and discharging currents to the gates of the driver transistors. Process-sensing transistors have gates tied to power or ground. Current through the process-sensing transistors changes with supply-voltage, temperature, and process variations. The currents through process-sensing transistors are used to generate process-compensated voltages that bias current sources and sinks to adjust process-dependent currents. Process-independent or fixed current sources and sinks use process-independent reference voltages ultimately generated from reference currents that are not sensitive to process variations. The process-dependent-currents are subtracted from the fixed currents to produce the charging and discharging currents.

A method and Apparatus for solar energy storage system uses gas for thermal transport for central tower solar thermal electric power plant to provide high quality, low cost, and continuously electric power generation. The storage contains a number of storage modules that each module can store energy for a given period of time. The thermal energy from central tower charges the modules one by one during the sunny time, while the thermal electric power plant discharge the modules one by one as long as it works. A control and a connection valve system control and connect the charge and discharge modules with the central tower and the power plant according to pre-arranged sequences. Fans at the cool side of the storage system push the circulation gas into the central tower or the thermal storage modules. In the discharge system, the hot gas from storage system is send to the heat exchange system, and to generate steam and to super heat steam for the power plant. In the charge system, the cold gas is pushed into the central receiver thermal exchange unit and to be heated, and the hot gas is then circulated back to storage system to charge up the storage system.