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Showing papers on "State of charge published in 1999"


Journal ArticleDOI
TL;DR: New detailed impedance date has been obtained on the discharge performance of primary lithium/sulfur dioxide cells and the use of fuzzy logic mathematics to analyze data obtained by impedance spectroscopy and/or coulomb counting techniques.

422 citations


Patent
23 Dec 1999
TL;DR: In this article, a smart battery self-monitors and maintains information about itself that includes its state of charge, its need for maintenance, and for conditions that indicate that it has reached the end of its useful life and should be discarded.
Abstract: A smart battery that self-monitors and maintains information about itself that includes its state of charge, its need for maintenance, and for conditions that indicate that it has reached the end of its useful life and should be discarded. The information maintained by the battery is then either displayed on an on-board display or is communicated to another device on a communication bus. The state of charge quantifies the smart battery's ability to reliably deliver charge to a host device and is dynamically adjusted over the lifetime of the smart battery. The state of charge may not exceed a full charge capacity value maintained by the smart battery and initially set to an estimated value. This full charge capacity value is dynamically adjusted throughout the life of the smart battery using information accumulated and maintained by the smart battery that indicates the smart battery's actual performance during use and by using messages received from a battery maintenance and testing system. The smart battery also accumulates and maintains information that indicates that the smart battery requires maintenance. A battery maintenance and testing system can read this need for maintenance from the smart battery and take the steps necessary to automatically maintain the smart battery. Conditions that indicate that the battery is defective or has exceeded its useful life are also maintained by the smart battery and communicated through the on-board display or to another devices over a communication bus. The battery is specially configured for easy assembly.

285 citations


Journal ArticleDOI
TL;DR: In this article, a 7.2V, 1.25 Ah sealed lithium-ion rechargeable battery has been studied for estimating its state-of-charge (SOC) by AC impedance.
Abstract: A 7.2V, 1.25 Ah sealed lithium-ion rechargeable battery has been studied for estimating its state-of-charge (SOC) by AC impedance. The dispersion of impedance data over the frequency range between 100 kHz and 25 mHz comprises an inductive part and two capacitive parts. As the inductive behaviour of the battery is attributed to the porous nature of the electrodes, only the capacitive components have been examined. The data obtained at several SOC values of the battery have been analyzed by a non-linear least-squares fitting procedure. The presence of two depressed semicircles in the capacitive region of the Nyquist plots necessitated the use of an electrical equivalent circuit containing constant phase elements instead of capacitances. The impedance parameters corresponding to the low-frequency semicircle have been found useful for predicting the SOC of the battery, mainly because the magnitude of these parameters and their variations are more significant than those of the high-frequency semicircle. The frequency maximum (f(max)) of the semicircle, the resistive component (Z') corresponding to f(max), the phase angle (phi) in the 5.0 Hz-0.1 Hz frequency range, the equivalent series resistance (R-s) and the equivalent series capacitance (C-s) have been identified as suitable parameters for predicting the SOC values of the lithium-ion battery.

177 citations


Patent
03 Dec 1999
TL;DR: In this paper, a control system for a hybrid vehicle with an engine and a motor, which are power sources, and a power storage unit for storing energy generated by the output from the engine and regenerative energy produced by regeneration of the motor when the vehicle decelerates is presented.
Abstract: The control system of the present invention is provided for a hybrid vehicle with an engine and a motor, which are power sources, and a power storage unit for storing energy generated by the output from the engine and regenerative energy produced by regeneration of the motor when the vehicle decelerates. Based on monitoring the state of charge of the power storage unit, when the stored energy is discharged so that the remaining charge is decreased from an initial state of charge, which was detected when the vehicle started running, by a predetermined amount, the function of the motor is switched from the discharging of the power storage unit to the charging of the power storage unit.

155 citations


Proceedings ArticleDOI
03 Oct 1999
TL;DR: In this paper, the development of a battery management system (BMS) for stand-alone photovoltaic (PV) energy systems is described. And the effect of measurement errors on the state of charge (SOC) of a lead acid battery is investigated.
Abstract: This paper outlines the development of a battery management system (BMS) for stand alone photovoltaic (PV) energy systems. The BMS calculates the state of charge (SOC) of a lead acid battery to determine the capacity over time. This enables intelligent control schemes to be implemented. A fully functioning prototype was constructed that involved both hardware and software design. Several tests were performed to evaluate the operation of the BMS. The effect of measurement errors on the SOC calculation were subsequently investigated.

139 citations


Patent
07 Jul 1999
TL;DR: In this article, a shared vehicle system includes a central station, at least one vehicle distribution port facility and a plurality or fleet of vehicles, each having a vehicle subsystem, where the information is processed to select a vehicle from the fleet to allocate to the user at the port facility.
Abstract: A shared vehicle system includes a central facility, at least one vehicle distribution port facility and a plurality or fleet of vehicles, each having a vehicle subsystem. In general, the central station and port facility and the vehicle subsystems communicate in a manner to allow a user to enter information at a port facility. That information is then communicated to the central facility, where the information is processed to select a vehicle from the fleet to allocate to the user at the port facility. Selection of a vehicle for allocation to a user may be based on selecting an available or soon to be available vehicle according to various algorithms that take into account the vehicles state of charge. The central station also communicates with the port facility and the vehicle subsystem to notify the user of the selected vehicle, to provide secure user access to the selected vehicle, to monitor the location and operating status of vehicles in the fleet, to monitor the state of charge of electric vehicles and to provide other functions. The vehicles communicate with the central station to notify the central station of the PIN number of the individual attempting to use the vehicle, and of vehicle parameters such as state of charge and location of the vehicle.

130 citations


Patent
22 Mar 1999
TL;DR: In this article, a method and apparatus for determining the state of charge of a battery include use of multiple battery tests to provide complementary insight into battery condition before, during, and after battery charging.
Abstract: A method and apparatus for determining the state of charge of a battery include use of multiple battery tests to provide complementary insight into battery condition before, during, and after battery charging. Battery testing is performed using a light resistive load, a heavy resistive load, a conductance tester, and a battery charger. During a preliminary charging stage, average battery current and a predicted battery temperature are used to determine whether or not the battery is capable of being substantially fully charged, thereby permitting avoidance of unneeded charging. In the later charging stage, the rate of change of battery cold cranking amps is monitored to detect an end of charge condition.

127 citations


Patent
26 Jan 1999
TL;DR: In this article, a smart battery self-monitors and maintains information about itself that includes its state of charge, its need for maintenance, and for conditions that indicate that it has reached the end of its useful life and should be discarded.
Abstract: A smart battery that self-monitors and maintains information about itself that includes its state of charge, its need for maintenance, and for conditions that indicate that it has reached the end of its useful life and should be discarded. The information maintained by the battery is then either displayed on an on-board display or is communicated to another device on a communication bus. The state of charge quantifies the smart battery's ability to reliably deliver charge to a host device and is dynamically adjusted over the lifetime of the smart battery. The state of charge may not exceed a full charge capacity value maintained by the smart battery and initially set to an estimated value. This full charge capacity value is dynamically adjusted throughout the life of the smart battery using information accumulated and maintained by the smart battery that indicates the smart battery's actual performance during use and by using messages received from a battery maintenance and testing system. The smart battery also accumulates and maintains information that indicates that the smart battery requires maintenance. A battery maintenance and testing system can read this need for maintenance from the smart battery and take the steps necessary to automatically maintain the smart battery. Conditions that indicate that the battery is defective or has exceeded its useful life are also maintained by the smart battery and communicated through the on-board display or to another devices over a communication bus. The battery is specially configured for easy assembly.

125 citations


Proceedings ArticleDOI
21 Sep 1999
TL;DR: A stochastic model of battery behavior, that emulates electrochemical mechanisms that are key to battery performance under pulsed discharge conditions, is introduced, and the role of traffic shaping in the quest to enhance battery behavior is emphasized.
Abstract: This paper introduces a stochastic model of battery behavior, that emulates electrochemical mechanisms that are key to battery performance under pulsed discharge conditions A pulsed discharge allows charge recovery during the idle periods Recovery depends on the state of charge of the battery and on the duration of the rest time period Using the postulated model, we derive the improvement to battery lifetime that results from pulsed current discharge driven by bursty stochastic transmissions The results emphasize the role of traffic shaping in the quest to enhance battery behavior

97 citations


Patent
09 Sep 1999
TL;DR: In this paper, a hybrid vehicle comprising an internal combustion engine controllably coupled to road wheels of the vehicle by a clutch, and having a turbocharger that is operated only when extra power is needed for an extended time, a traction motor coupled to the road wheels, both motors being operable as generators, a battery bank for providing electrical energy to and accepting energy from said motors, and a microprocessor for controlling these components, is operated in different modes, depending on its instantaneous torque requirements, the state of charge of the battery bank, and other operating parameters.
Abstract: A hybrid vehicle comprising an internal combustion engine controllably coupled to road wheels of the vehicle by a clutch, and having a turbocharger that is operated only when extra power is needed for a extended time, a traction motor coupled to road wheels of said vehicle, a starting motor coupled to the engine, both motors being operable as generators, a battery bank for providing electrical energy to and accepting energy from said motors, and a microprocessor for controlling these components, is operated in different modes, depending on its instantaneous torque requirements, the state of charge of the battery bank, and other operating parameters. The mode of operation is selected by the microprocessor in response to a control strategy.

92 citations


Patent
07 Jul 1999
TL;DR: In this paper, a shared vehicle system includes a central station, at least one vehicle distribution port facility and a plurality or fleet of vehicles, each having a vehicle subsystem, where the information is processed to select a vehicle from the fleet to allocate to the user at the port facility.
Abstract: A shared vehicle system includes a central facility, at least one vehicle distribution port facility and a plurality or fleet of vehicles, each having a vehicle subsystem. In general, the central station and port facility and the vehicle subsystems communicate in a manner to allow a user to enter information at a port facility. That information is then communicated to the central facility, where the information is processed to select a vehicle from the fleet to allocate to the user at the port facility. Selection of a vehicle for allocation to a user may be based on selecting an available or soon to be available vehicle according to various algorithms that take into account the vehicles state of charge. The central station also communicates with the port facility and the vehicle subsystem to notify the user of the selected vehicle, to provide secure user access to the selected vehicle, to monitor the location and operating status of vehicles in the fleet, to monitor the state of charge of electric vehicles and to provide other functions. The vehicles communicate with the central station to notify the central station of the PIN number of the individual attempting to use the vehicle, and of vehicle parameters such as state of charge and location of the vehicle.

Patent
02 Feb 1999
TL;DR: In this article, the controller disconnects non-essential loads of the equipment from the battery to conserve what charge remains in the battery, and disable the ignition during inactive periods unless the proper reactivation signal is received.
Abstract: Battery powered equipment is provided with a controller which monitors the voltage supplied by the battery. Should the battery voltage drop below a preset level when the equipment is inactive, the controller disconnects non-essential loads of the equipment from the battery to conserve what charge remains in the battery. When used with a motor vehicle the controller may be tied into the security system and disable the ignition during inactive periods unless the proper reactivation signal is received.

Patent
07 Jul 1999
TL;DR: In this article, a shared vehicle system includes a central station, at least one vehicle distribution port facility and a plurality or fleet of vehicles, each having a vehicle subsystem, where the information is processed to select a vehicle from the fleet to allocate to the user at the port facility.
Abstract: A shared vehicle system includes a central facility, at least one vehicle distribution port facility and a plurality or fleet of vehicles, each having a vehicle subsystem. In general, the central station and port facility and the vehicle subsystems communicate in a manner to allow a user to enter information at a port facility. That information is then communicated to the central facility, where the information is processed to select a vehicle from the fleet to allocate to the user at the port facility. Selection of a vehicle for allocation to a user may be based on selecting an available or soon to be available vehicle according to various algorithms that take into account the vehicles state of charge. The central station also communicates with the port facility and the vehicle subsystem to notify the user of the selected vehicle, to provide secure user access to the selected vehicle, to monitor the location and operating status of vehicles in the fleet, to monitor the state of charge of electric vehicles and to provide other functions. The vehicles communicate with the central station to notify the central station of the PIN number of the individual attempting to use the vehicle, and of vehicle parameters such as state of charge and location of the vehicle.

Journal ArticleDOI
TL;DR: A control method for the motor torque to avoid damage to the battery, when the battery is at a low state of charge is described.
Abstract: Since each component of a hybrid system has its own limit of performance, the vehicle power depends on the weakest component. So it is necessary to design the balance of the components. The vehicle must be controlled to operate within the performance range of all the components. We designed the specifications of each component backward from the required drive force. In this paper we describe a control method for the motor torque to avoid damage to the battery, when the battery is at a low state of charge.

Patent
02 Jul 1999
TL;DR: In this paper, a battery management for a hybrid drive system for a vehicle recovers input and output performance of a battery if the battery temperature is low or if the internal resistance is greater than or equal to a predetermined value.
Abstract: A battery management for a hybrid drive system for a vehicle recovers input and output performance of a battery if the battery temperature is low. If the battery temperature is less than or equal to a predetermined value (or if the battery internal resistance is greater than or equal to a predetermined value), the battery needs to recover its input and output performance. Under this condition, the state of charge (SOC) of the battery is determined and compared with a predetermined value. The comparison result is used to determine whether the battery is capable of discharging or the battery needs charging. If SOC is greater than or equal to the predetermined value, a controller conducts forced discharge from the battery to operate an electric motor of the hybrid drive system in power mode. This forced discharge causes an increase ion the battery temperature, thus causing the battery to recover its input and output performance.

Patent
07 Jul 1999
TL;DR: In this paper, a shared vehicle system includes a central station, at least one vehicle distribution port facility and a plurality or fleet of vehicles, each having a vehicle subsystem, where the information is processed to select a vehicle from the fleet to allocate to the user at the port facility.
Abstract: A shared vehicle system includes a central facility, at least one vehicle distribution port facility and a plurality or fleet of vehicles, each having a vehicle subsystem. In general, the central station and port facility and the vehicle subsystems communicate in a manner to allow a user to enter information at a port facility. That information is then communicated to the central facility, where the information is processed to select a vehicle from the fleet to allocate to the user at the port facility. Selection of a vehicle for allocation to a user may be based on selecting an available or soon to be available vehicle according to various algorithms that take into account the vehicles state of charge. The central station also communicates with the port facility and the vehicle subsystem to notify the user of the selected vehicle, to provide secure user access to the selected vehicle, to monitor the location and operating status of vehicles in the fleet, to monitor the state of charge of electric vehicles and to provide other functions. The vehicles communicate with the central station to notify the central station of the PIN number of the individual attempting to use the vehicle, and of vehicle parameters such as state of charge and location of the vehicle.

Patent
14 May 1999
TL;DR: In this paper, a state of charge indicator of a lithium ion battery computes a cell open circuit voltage from a SOC-cell voltage characteristic map, and displays the SOC on a display device.
Abstract: A state of charge indicator of a lithium ion battery computes a state of charge (SOC) corresponding to a cell open circuit voltage from a SOC-cell open circuit voltage characteristic map, and displays the SOC on a display device. Herein, the SOC-cell open circuit voltage characteristics are obtained by defining the battery charge amount when the open circuit voltage of the cell is 3.9 V as SOC=100%, and defining the battery charge amount when the open circuit voltage of the cell is 3.5 V as SOC=100%. By defining SOC=100% and SOC=0% in this way, the SOC can be correctly computed and displayed even if the battery has deteriorated.

Patent
30 Aug 1999
TL;DR: In this paper, an apparatus for controlling a charge/discharge state of a battery in a hybrid car can be provided that quickly and easily controls the temperature of the battery to a predetermined temperature.
Abstract: The temperature of a battery in a hybrid car is supervised by temperature sensors. When the temperature of the battery is at a temperature not exceeding a predetermined temperature, a battery ECU issues a command to a control CPU to perform forcible charge/discharge of the battery to raise the temperature of the battery. When raising of the temperature is performed by charging, a requested output from an engine is increased as compared with a usual state. In such a state, motor-generators are operated as generators so as to generate electric power and charge the battery by passing an electric current to the battery rather than generating a driving force. When raising of the temperature is performed by discharging, the requested output from the engine is reduced as compared with the usual state. In this case, the motor-generators are operated as drive motors to consume electric power so as to draw electric current from the battery causing discharge of the battery. The electric current allowed to flow at this time causes internal resistance to be generated in the battery that heats the battery from an inside portion thereof. Thus, an apparatus for controlling a charge/discharge state of a hybrid car can be provided that quickly and easily controls the temperature of the battery to a predetermined temperature.

Patent
David N. Klein1
20 Oct 1999
TL;DR: In this article, the case of a portable electronic device includes a case for carrying a battery and a processor responsive to the discharge signal from the charge sensor circuit to produce a signal corresponding to an amount of time prior to discharge of the battery based on a current rate of discharge.
Abstract: A battery pack for a portable electronic device includes a case for carrying a battery. The case supports a charge sensing circuit carried by the case, the charge sensing circuit producing a discharge signal corresponding to a measurement of an amount of charge removed from a battery. The case also supports a processor responsive to the discharge signal from the charge sensor circuit to produce a signal corresponding to an amount of time prior to discharge of the battery based on a current rate of discharge and a display responsive to the signal to display a time period corresponding to the amount of time to discharge the battery based upon the current rate of discharge of the battery.

Patent
07 Jul 1999
TL;DR: In this paper, a shared vehicle system includes a central station, at least one vehicle distribution port facility and a plurality or fleet of vehicles, each having a vehicle subsystem, where the information is processed to select a vehicle from the fleet to allocate to the user at the port facility.
Abstract: A shared vehicle system includes a central facility, at least one vehicle distribution port facility and a plurality or fleet of vehicles, each having a vehicle subsystem. In general, the central station and port facility and the vehicle subsystems communicate in a manner to allow a user to enter information at a port facility. That information is then communicated to the central facility, where the information is processed to select a vehicle from the fleet to allocate to the user at the port facility. Selection of a vehicle for allocation to a user may be based on selecting an available or soon to be available vehicle according to various algorithms that take into account the vehicles state of charge. The central station also communicates with the port facility and the vehicle subsystem to notify the user of the selected vehicle, to provide secure user access to the selected vehicle, to monitor the location and operating status of vehicles in the fleet, to monitor the state of charge of electric vehicles and to provide other functions. The vehicles communicate with the central station to notify the central station of the PIN number of the individual attempting to use the vehicle, and of vehicle parameters such as state of charge and location of the vehicle.

Patent
07 Jul 1999
TL;DR: In this article, a shared vehicle system includes a central station, at least one vehicle distribution port facility and a plurality or fleet of vehicles, each having a vehicle subsystem, where the information is processed to select a vehicle from the fleet to allocate to the user at the port facility.
Abstract: A shared vehicle system includes a central facility, at least one vehicle distribution port facility and a plurality or fleet of vehicles, each having a vehicle subsystem. In general, the central station and port facility and the vehicle subsystems communicate in a manner to allow a user to enter information at a port facility. That information is then communicated to the central facility, where the information is processed to select a vehicle from the fleet to allocate to the user at the port facility. Selection of a vehicle for allocation to a user may be based on selecting an available or soon to be available vehicle according to various algorithms that take into account the vehicles state of charge. The central station also communicates with the port facility and the vehicle subsystem to notify the user of the selected vehicle, to provide secure user access to the selected vehicle, to monitor the location and operating status of vehicles in the fleet, to monitor the state of charge of electric vehicles and to provide other functions. The vehicles communicate with the central station to notify the central station of the PIN number of the individual attempting to use the vehicle, and of vehicle parameters such as state of charge and location of the vehicle.

Patent
03 Jun 1999
TL;DR: In this paper, a battery charger for Ni-CAD and Ni-MH batteries is described, which turns a current source into a controlled voltage source which keys off a signal representative of the voltage level of the battery during the charging process and turns the current source ON and OFF to assure that the battery does not exceed a given voltage level.
Abstract: A compact, economical and fast battery charger for Ni-CAD and Ni-MH batteries turns a current source into a controlled voltage source which keys off a signal representative of the voltage level of the battery during the charging process and turns the current source ON and OFF to assure that the battery during the charging process does not exceed a given voltage level. The apparatus includes in par a ballasting resistor in series with the battery to compensate for the low resistance of the battery and an open collector voltage comparator which establishes high and low voltage set points for turning the current source ON and OFF at the appropriate times. The method and apparatus includes a visual display responsive to a signal which produces on the visual display an indication of the state of charge of the battery during a charging cycle. A circuit board has a long U-shaped trace extending around a notch in the board, on each side of each is mounted on battery. The printed circuit board has a trimming resistor arrangement which allows for trimming to be done using a drill.

Patent
29 Sep 1999
TL;DR: In this article, a technique of operating a Li-ion battery is proposed for maximizing battery life, which calls for charging the battery at a lower temperature than the temperature at which discharge begins, and discharge at a temperature T2, in the range of about +5°C to +30°C, T2 being higher than T1.
Abstract: A technique of operating a lithium-ion (Li-ion) battery is proposed for maximizing battery life. In a first instance, this technique calls for charging the battery at a lower temperature than the temperature at which discharge begins. Preferably, the battery is charged at a temperature T1 in the range between about +5°C and -20°C; and discharged at a temperature T2, in the range of about +5°C to +30°C, T2 being higher than T1. In another instance proposed by the invention, the battery is charged to an elevated state of charge which is above an initial state of charge at a temperature T1 between about +5°C and -20°C which is lower than a temperature T2, in the range of about +5°C to +30°C, at which discharge begins. In still another instance proposed by the invention, after the battery has been charged and discharged during the eclipse season, it is then charged to an intermediate charge level between about 40% and about 60% state of charge over a relatively long lapsed duration of time, about one month to about six months, and thereafter, the battery is maintained at this intermediate charge level.

Patent
11 Nov 1999
TL;DR: In this paper, a reduction in charging time is achieved while suppressing any deterioration in the lifetime of the battery by reducing the battery temperature at charge commencement and upper limit value of battery temperature.
Abstract: A reduction in charging time is achieved while suppressing any deterioration in the lifetime of the battery. A battery temperature increase margin is determined from the battery temperature at charge commencement and the upper limit value of the battery temperature. Moreover, the target charging capacity is determined from the initial state of charge at charge commencement and the target state of charge at charge completion. Furthermore, a value of an upper limit of the battery temperature increase is determined from these. Then, the battery charge current maximum value is set by map referral based on the value of an upper limit of the battery temperature increase such that the temperature of the battery during charging does not exceed the upper limit value. A driver performs the battery charging using a charge current value that has been set on the basis of the battery charge maximum value.

Patent
10 Sep 1999
TL;DR: In this article, a hybrid vehicle comprising an internal combustion engine (40) controllably coupled to road wheels (34) of the vehicle by a clutch, a traction motor (25), and a starting motor coupled to the engine, both motors being operable as generators, a battery bank (22) for providing electrical energy to and accepting energy from said motors, and a microprocessor (48) for controlling these components is operated in different modes, depending on the vehicle's instantaneous torque requirements, the state of charge of the battery bank, and other operating parameters.
Abstract: A hybrid vehicle comprising an internal combustion engine (40) controllably coupled to road wheels (34) of the vehicle by a clutch (51), a traction motor (25) coupled to road wheels of said vehicle, a starting motor (21) coupled to the engine, both motors being operable as generators, a battery bank (22) for providing electrical energy to and accepting energy from said motors, and a microprocessor (48) for controlling these components is operated in different modes, depending on the vehicle's instantaneous torque requirements, the state of charge of the battery bank, and other operating parameters. The mode of operation is selected by the microprocessor in response to a control strategy resulting in improved fuel economy and reduced emission. The engine may be fitted with a turbocharger (100) operated in response to a control signal for extended high-load operation.

Patent
Anil Paryani1, Yasuyuki Sando1
31 Mar 1999
TL;DR: In this paper, the authors present a method and an apparatus for charging a battery which is operable to normally charge the battery at a first state of charge setting, to determine when the battery has been undercharged a predetermined number of times, and to charge a battery with a second state of second charge setting after the battery is undercharged the predetermined number.
Abstract: A method and apparatus for charging a battery which is operable to normally charge the battery at a first state of charge setting, to determine when the battery has been undercharged a predetermined number of times, and to charge the battery at a second state of charge setting after the battery is undercharged the predetermined number of times. The second state of charge setting is greater than the first state of charge setting. The method includes determining when the state of charge of the battery is below a predetermined level, charging the battery at the first state of charge setting, calculating a number of charging times when the battery was charged below the predetermined level after the last time the battery was charged at the predetermined level, and charging the battery with a second state of second charge setting when the calculated number of charging times equals a predetermined number. The apparatus includes a sensor for sensing the state of charge of the battery, a counter for counting the number of charging times that the battery was charged below a predetermined level after the last time the battery was charged to the predetermined level, and a charger for applying the second state of charge setting when the number of charging times counted by the counter equals the predetermined number.

Journal ArticleDOI
TL;DR: In this article, an in-situ method for measuring the variation of battery stack thickness employing a linear voltage displacement transducer device is described, and the thickness changes are reversible within a single charge-discharge cycle.

Patent
18 Mar 1999
TL;DR: In this paper, the instantaneous charge state of a thermal energy store in a heat exchanger circuit was determined and the power extracted from the store was regulated to satisfy a user's air conditioning demand.
Abstract: The method involves determining the instantaneous charge state of a thermal energy store (3) in a heat exchanger circuit (4) carrying a thermal bearer liquid and regulating the heating or cooling power extracted from the store accordingly. A user air conditioning demand is fulfilled if it is compatible with the thermal energy store's state of charge, the vehicle's driving state and the heat exchanger circuit parameters, otherwise reduced heating or cooling power is output. An Independent claim is also included for an arrangement for air conditioning a useful space in a motor vehicle.

Patent
14 Oct 1999
TL;DR: In this paper, the acid capacity of a battery is determined from a curve of the rest voltage U00 linearized by the formula SOC1 =U002 /C1 -C2 as a function of the state of charge of the battery from which the absolute state-of-charge is calculated as SOC1 ·Q0 from the internal resistance R1, a preassigned temperature and the last determined state of charges, a rest voltage is predicted for a later time from which, with the current necessary for starting the engine known, a pronouncement can be derived concerning the
Abstract: In a process for determining the state of charge and the peak current loadability of batteries in the currentless pauses before and after a loading phase the no-load voltages U01 and U02 are measured From them, with allowance for battery-specific parameters, especially the time curve of the no-load voltage, the true battery rest voltages U001 and U002 are computed During the loading phase the converted current quantity q is measured and from the relationship U002 -U001 =C1 ·q/Q0 the acid capacity Q0 of the battery is found The relative state of charge SOC1 is determined from a curve of the rest voltage U00 linearized by the formula SOC1 =U002 /C1 -C2 as a function of the state of charge of the battery from which the absolute state of charge is calculated as SOC1 ·Q0 From the internal resistance R1, a preassigned temperature and the last determined state of charge, a rest voltage is predicted for a later time from which, with the current necessary for starting the engine known, a pronouncement can be derived concerning the starting capacity of the battery

Patent
26 Jan 1999
TL;DR: In this paper, a process for improving the charging and discharging capacity of storage batteries at low temperatures is described, which is accomplished by raising their temperature, using for this purpose the energy stored in the batteries.
Abstract: The invention pertains to a process for improving the charging and discharging capacity of storage batteries at low temperatures. The improvement in the charging and discharging of storage batteries is accomplished by raising their temperature, using for this purpose the energy stored in the batteries. The process is conducted in such a way that the temperature and at least one value characterizing the state of charge are measured before the beginning of the heating and during the heating and the storage battery is discharged through an electrical component introducing thermal energy into it, at which time the discharge is terminated when either the target loadability in the discharging or charging was achieved or the state of charge decreases below a threshold value.