Showing papers on "State of charge published in 1998"

Battery power source device

Abstract: A power source has a battery pack housing a plurality of interconnected battery modules wherein a plurality of single cells are connected serially. A blower is provided which forces air through the battery pack to maintain the battery modules at a correct temperature. A controller controls the blower in accordance with data provided by sensors which detect voltage, current and temperature. The controller outputs the data and a state of charge. A charging/discharging current circuit includes a relay for interrupting charging and discharging of the battery modules in the event of failure and also includes a rush current prevention resistor and a current sensor. The controller permits the power source to be maintained in a correct operating condition wherein neither overcharging nor undercharging occurs.

Hybrid electric vehicle with battery management

Abstract: A hybrid electric vehicle comprises an electric motor, a battery pack for the electric motor, a generator driven by an engine to provide electric power used for charging the battery pack, and a battery management for the battery pack. The battery management determines a current value of battery temperature (BT) of the battery pack and a current value of state of charge (SOC) within the battery pack. What are stored are a first set of varying SOC values and a second set of varying SOC values against varying BT values. The first set of varying SOC values are minimum SOC values required for the battery pack to produce a constant electric power output at varying BT values. The second set of varying SOC values are each indicative of an allowable upper limit to the quantity of electric charge that will accumulate in the battery pack due to operation of charging the battery pack with a constant electric power input at a corresponding BT value. The battery management provide an actuator command for control of electric power input upon charging the battery pack in response to the current value of BT, the current value of SOC, the first set of varying SOC values and the second set of varying SOC values.

Electric vehicle with variable efficiency regenerative braking depending upon battery charge state

Abstract: An electric vehicle is controlled to conform its operation to that of a conventional internal-combustion-engine powered vehicle. In some embodiments, the charging of the batteries by the auxiliary source of electricity and from dynamic braking is ramped in magnitude when the batteries lie in a state of charge between partial charge and full charge, with the magnitude of the charging being related to the relative state of charge of the battery. The deficiency between traction motor demand and the energy available from the auxiliary electrical source is provided from the batteries in an amount which depends upon the state of the batteries, so that the full amount of the deficiency is provided when the batteries are near full charge, and little or no energy is provided by the batteries when they are near a discharged condition. At charge states of the batteries between near-full-charge and near-full-discharge, the batteries supply an amount of energy which depends monotonically upon the charge state. Charging of the batteries from the auxiliary source is reduced during dynamic braking when the batteries are near full charge. Control of the amount of energy returned during dynamic braking may be performed by control of the transducing efficiency of the traction motor operated as a generator.

A method for determining state-of-charge using an intelligent system

Abstract: A method for determining state of charge, SOC, of an electrochemical device (12) using fuzzy logic (i.e., an intelligent system) is presented. SOC of an electrochemical device is determined by an internal characteristic or parameter (or external operating and environmental conditions) (14) with an intelligent system (16). The electrochemical device (12) comprises such devices as primary ('throwaway') batteries, rechargeable batteries, fuel cells, a hybrid battery containing a fuel cell electrode and electrochemical supercapacitors. The intelligent system (16) is trained in the relationship between the characteristic of the electrochemical device and the SOC of the electrochemical device.

Hybrid electric vehicle with reduced auxiliary power to batteries during regenerative braking

Abstract: An electric vehicle is controlled to conform its operation to that of a conventional internal-combustion-engine powered vehicle In some embodiments, the charging of the batteries by the auxiliary source of electricity and from dynamic braking is ramped in magnitude when the batteries lie in a state of charge between partial charge and full charge, with the magnitude of the charging being related to the relative state of charge of the battery The deficiency between traction motor demand and the energy available from the auxiliary electrical source is provided from the batteries in an amount which depends upon the state of the batteries, so that the full amount of the deficiency is provided when the batteries are near full charge, and little or no energy is provided by the batteries when they are near a discharged condition At charge states of the batteries between near-full-charge and near-full-discharge, the batteries supply an amount of energy which depends monotonically upon the charge state Charging of the batteries from the auxiliary source is reduced during dynamic braking when the batteries are near full charge Control of the amount of energy returned during dynamic braking may be performed by control of the transducing efficiency of the traction motor operated as a generator

Hybrid electric vehicle with traction motor drive allocated between battery and auxiliary source depending upon battery charge state

Abstract: An electric vehicle is controlled to conform its operation to that of a conventional internal-combustion-engine powered vehicle. In some embodiments, the charging of the batteries by the auxiliary source of electricity and from dynamic braking is ramped in magnitude when the batteries lie in a state of charge between partial charge and full charge, with the magnitude of the charging being related to the relative state of charge of the battery. The deficiency between traction motor demand and the energy available from the auxiliary electrical source is provided from the batteries in an amount which depends upon the state of the batteries, so that the full amount of the deficiency is provided when the batteries are near full charge, and little or no energy is provided by the batteries when they are near a discharged condition. At charge states of the batteries between near-full-charge and near-full-discharge, the batteries supply an amount of energy which depends monotonically upon the charge state. Charging of the batteries from the auxiliary source is reduced during dynamic braking when the batteries are near full charge. Control of the amount of energy returned during dynamic braking may be performed by control of the transducing efficiency of the traction motor operated as a generator.

Controller for electric vehicle and electric vehicle using the same

Abstract: There is disclosed a controller for an electric vehicle that allows for securing a sufficient battery capacity and is able to substantially avoid giving an uncomfortable feeling to the crew even if an engine for power generation is started. The controller comprises a power generation control unit which makes a generator of the electric vehicle generate electric power by starting a generator-driving engine of the electric vehicle in the case that an SOC (state of charge) of a battery of the electric vehicle is equal to or less than a first value, and further makes the generator generate the electric power by starting the generator-driving engine in the case that the SOC of the battery is equal to or less than a second value larger than the first value and a predetermined condition is satisfied. Further, an electric vehicle provided with such a controller is also disclosed.

Apparatus for regulating state of charge of cells of battery set

Abstract: There is disclosed an apparatus for precisely regulating, with a simple structure, a state of charge of each of cells constituting a battery set. In the apparatus, a detection circuit, a plurality of discharge circuit connected to corresponding one of the cells, respectively, and a control circuit are provided. The detection circuit detects open-circuit voltage of each of the plurality of cells, the plurality of discharge circuit discharges a charging electricity charged in the cells, and the control circuit controls to uniform the state of charge of each of the cells, utilizing the discharge circuit respectively corresponding to each of the cells, based on the open-circuit voltage of each of the cells detected by the detection circuit.

Plate with switch for monitoring multi-cell accumulator battery, especially for electric vehicles

Abstract: The plate (1) is cut out to form segments (3). The segments determine each cell and are connected to the pole connections. The segments carry take-offs for the temperature and voltage of the cell. One segment at least has connectors (5) provided for input and output of a data bus. Switches allow monitoring of accumulator, state of charge.

Battery power source supply with coolant flow

Abstract: A power source has a battery pack housing a plurality of interconnected battery modules wherein a plurality of single cells are connected serially. A blower is provided which forces air through the battery pack to maintain the battery modules at a correct temperature. A controller controls the blower in accordance with date provided by sensors which detect voltage, current and temperature. The controller outputs the data and a state of charge. A charging/discharging current circuit includes a relay for interrupting charging and discharging of the battery modules in the event of failure and also includes a rush current prevention resistor and a current sensor. The controller permits the power source to be maintained in a correct operating condition wherein neither overcharging nor undercharging occurs.

Optical state-of-charge monitor for batteries

Abstract: A method and apparatus for determining the instantaneous state-of-charge of a battery in which change in composition with discharge manifests itself as a change in optical absorption. In a lead-acid battery, the sensor comprises a fiber optic system with an absorption cell or, alternatively, an optical fiber woven into an absorbed-glass-mat battery. In a lithium-ion battery, the sensor comprises fiber optics for introducing light into the anode to monitor absorption when lithium ions are introduced.

Electric vehicle with battery regeneration dependant on battery charge state

Abstract: An electric vehicle is controlled to conform its operation to that of a conventional internal-combustion-engine powered vehicle. In some embodiments, the charging of the batteries by the auxiliary source of electricity and from dynamic braking is ramped in magnitude when the batteries lie in a state of charge between partial charge and full charge, with the magnitude of the charging being related to the relative state of charge of the battery. The deficiency between traction motor demand and the energy available from the auxiliary electrical source is provided from the batteries in an amount which depends upon the state of the batteries, so that the full amount of the deficiency is provided when the batteries are near full charge, and little or no energy is provided by the batteries when they are near a discharged condition. At charge states of the batteries between near-full-charge and near-full-discharge, the batteries supply an amount of energy which depends monotonically upon the charge state. Charging of the batteries from the auxiliary source is reduced during dynamic braking when the batteries are near full charge. Control of the amount of energy returned during dynamic braking may be performed by control of the transducing efficiency of the traction motor operated as a generator.

Apparatus and method for coulometric metering of battery state of charge

Abstract: The apparatus for metering the state of charge of a battery has a battery current sensor providing a voltage signal dependent on a current flowing into or out of the battery, an integrator for integrating the voltage signal, a window detector circuit providing an output signal each time an output of the integrator reaches an upper or lower threshold voltage level, a digital processing device utilizing the output signals of the window detector circuit to construct a digital battery charge state model, and a switch arrangement for reversing connection of the battery current sensor to the integrator periodically so as to cancel effect of any voltage offset in the output of the integrator.

Anti-theft system for disabling a vehicle engine

Abstract: An anti-theft system disables a vehicle engine upon detection of an unauthorized vehicle start-up. A fob transmitter sends a coded frequency signal that is received to arm the anti-theft system. When armed, the system monitors whether the engine is running using a combination of vibration detection, voltage fluctuations in the battery voltage and the actual battery voltage. In the event of an unauthorized start-up, the system opens a switch to disconnect the battery and closes a switch to connect the alternator to ground through the resistor. In order to prevent a vehicle from being jump started by using a second battery, the system resets the connection of the alternator to ground at periodic intervals thereby repeatedly testing for the presence of the second battery and cause the engine to stall after the second battery is disconnected. A driver entry detection portion of the system determines whether someone has entered the vehicle, and issues a chirp signal to notify the occupant that the system is armed. An algorithm determines whether the battery voltage has reached a minimum state of charge for reliably starting the vehicle, and also disconnects the battery once the minimum level has been reached.

State of charge estimation of sealed lead-acid batteries used for electric vehicles

Abstract: Various estimation methods for the state of charge of the sealed lead-acid battery have been proposed. However, no method can accurately predict the residual capacity. A new equation of estimating the residual capacity of the sealed lead-acid battery is proposed. The experiments were performed for verification of the proposal estimation.

Method and device for detecting a state of charge of a battery assembly, and battery assembly charge and discharge control device

Abstract: Variation of the charged amount among battery blocks composing a battery assembly is detected. By subtracting the detected value of the variation from the width between the upper limit value and the lower limit value of the charged amount, the movable range of the charged amount is found. The position of the present charged amount is detected as the state of charge. For example, it is arranged that both ends of the movable range are 0% and 100%, and that the movable range is the full scale. Then, the position of the charged amount on this scale is specified by the ratio %. The detection of the state of charge in which the variation in charged amount and the change of the movable range are considered, is performed, and on the basis of this state of charge, a preferable charge and discharge control is performed.

An adaptive battery monitoring system for an electric vehicle

Abstract: In electric vehicles it is important to know the state of charge of the batteries in order to prevent vehicle strandings and to ensure that the full range of the vehicle is exploited. It is also useful to know state of health information about the batteries to predict when the batteries need replacing. This paper describes a battery monitoring system that is able to calculate the state of charge and state of health of multiple batteries in a battery bank. It has been designed specifically to monitor lead-acid batteries in an electric car environment using noninvasive measurement techniques. The monitor incorporates an adaptive monitoring method, which is based on coulometric measurements when the batteries are under load and predicted open circuit voltage measurements under noload conditions.

Device and a process for monitoring the state of charge of a battery

Abstract: A device and method for determining the state of charge of a battery includes a microprocessor-controlled arithmetic unit connected in parallel to the terminal voltage of the battery. The arithmetic unit is selectively connectable with an ohmic reference resistance placed in parallel with a load resistance which is arranged in series with the battery, and with a capacitor chargeable or dischargeable via the arithmetic unit. The arithmetic unit is further capable of acquiring a value of the voltage drop across the capacitor. The arithmetic unit is operable in a first operating state in which it is disconnected from the reference resistance, and a second operating state in which the arithmetic unit is connected with the resistance. After the capacitor is charged to the terminal voltage of the battery, it is allowed to discharge. With the arithmetic unit in the first operating state, a first point in time marked by the voltage across the capacitor reaching a first threshold value is registered. In the second operating state, with the reference resistor connected to the arithmetic unit, a second point in time indicated by the voltage across the capacitor reaching a second threshold value is registered. The time difference between reaching the two threshold values represents a measured value proportional to the internal resistance, which in turn directly relates to the residual capacity of the battery.

Nickel battery charging method and apparatus

Abstract: Raising the charging acceptability of nickel battery. The setting of the initial SOC (state of charge) of hybrid electric vehicle battery to X% (for example 50%) is performed by two steps. The first one is a constant current charge until a fully charged state (S11, S12). Secondly, a discharging is performed until the target SOC of X% is obtained (S13, S14). This enables the interior part of the nickel positive electrode active particles to be assumed as a charged state so that during normal operation, charging and discharging can be performed relatively in the surface layer. This can increase the efficiency of oxidation-reduction in the nickel positive electrode, thereby raising the charging acceptability.

Condition monitoring system for batteries

Abstract: The invention relates to a control system of battery health. One or more cells of a float charged battery are shunted periodically through a current generator; or through a switch and a resistor. The system measures impedance and/or state of charge by sampling the change in cell voltage during a shunt period or between sequel shunt periods.

Method for determining an end of discharge voltage for a secondary battery

Abstract: Method for determining a determination voltage (end of discharge voltage) of a secondary battery having a nickel-hydroxide positive electrode based on the state of charge of the battery. The end of discharge voltage is determined in consideration of the voltages when the state of charge reaches a permissible lower limit after first and subsequent discharges of the battery. The voltage at which the state of charge reaches the lower limit for discharges after the first discharge gradually decreases due to a memory effect. As a result, the end of discharge voltage is lower than the voltage at which the state of charge reaches the lower limit after the first discharge.

Driving force control unit of vehicle

Abstract: PROBLEM TO BE SOLVED: To enable engine horsepower to be generated with optimal fuel efficiency, by synthesizing the quotient in which the required battery horsepower is divided by the vehicle speed and the target horsepower, and setting both the target engine torque and the target input shaft speed of the automatic transmission based on the synthesized target driving force. SOLUTION: Output signals from sensors 21 through 25 which detect vehicle speed VSP, accelerator pressure APS, engine speed Ne, input shaft speed Ni, and state of charge SOC, respectively, are introduced to a driving force control controller 10, which first calculates the target driving force Fd. Next, the required battery horsepower Wb is calculated using a map based on the state of charge SOC. Then, the quotient from dividing Wb by VSP is calculated as the required driving force Fdm of the motor generator 1, 4, and difference of Wb from Fd is calculated as the required driving force Fde of the engine 2. The target engine speed Ne is then calculated based on the Fde and VSP, after which the corresponding required engine torque the is calculated.

State of charge indicators for a battery

Abstract: The present invention relates to state of charge indicators for a battery. One aspect of the present invention utilizes expansion and contraction displacements of an electrode plate of a battery to gauge the state of charge in the battery. One embodiment of a battery of the present invention includes an anodic plate; a cathodic plate; an electrolyte in contact with the anodic and cathodic plates; plural terminals individually coupled with one of the anodic and cathodic plates; a separator intermediate the anodic and cathodic plates; an indicator configured to indicate an energy level of the battery responsive to movement of the separator; and a casing configured to house the anodic and cathodic plates, electrolyte, and separator.

Method and device for detecting charging state of battery

Abstract: PROBLEM TO BE SOLVED: To accurately determine the state of charge(SOC) of a battery. SOLUTION: A battery control unit 20 detects the current and the voltage of a battery 16 successively. Here, every time the current value crosses zero, the average current and average voltage of the positive (discharging) or negative (charging) section are calculated. At discharging, a discharging voltage reference value, a voltage when the SOC of the battery is 20%, is determined based on the average current so obtained, and it is compared with the average voltage. Also at charging, a charging voltage reference value, a voltage when the SOC of the battery is 80% is calculated and is compared with the average voltage. This makes it possible to accurately discriminate that the current state is between SOC value 20% and 80%.

Device and method for monitoring the state of charge of a battery

Abstract: The arrangement has a measurement device for the pole voltage (U1) and a device for computing the internal impedance (Ri) of the battery. A further device determines the state of charge of the battery from the measured parameters. A microprocessor-controlled computer unit ( mu C), which is connected in parallel with the pole voltage, controls the charging and discharging of a capacitor (C) and measures and the voltage (UC) across the capacitor. The computer unit records the times when a first and second threshold voltage is reached, in modes without and with a resistance (R3) connected to the computer. The internal impedance is derived from the difference between the times at which the two thresholds are reached.

Development of high power nickel-cadmium batteries for hybrid vehicles

Abstract: A new high performance, long life, low cost, nickel cadmium battery has been developed for heavy hybrid vehicles. The Saft STX 600 offers the highest power to weight and longest life available with 500 W/kg peak power, 350 W/kg at 50% state of charge, and over 600 K cycles at 2% depth of discharge. Development work was funded through a cost share grant from the FTA to the New York State Consortium. The battery was developed to provide lighter weight, smaller size, lower cost energy storage for the series hybrid propulsion system on the Consortium's highly successful low floor demonstration bus. The battery was designed with durability to level peaks and valleys of propulsion power for 6 years on demanding New York City bus routes. Cell construction is based on Saft's time tested aviation battery technology and weighing only 2.0 kg offers users a lightweight alternative for their HEV application needs. In this paper, we focus on the specific design criteria of this cell, elements of the development program, and characterization test results.

Battery control equipment

Abstract: PROBLEM TO BE SOLVED: To perform charging when an overdischarge cell is generated. SOLUTION: A voltage detector 12 detects a voltage of a battery block of an assembly battery 10. When voltage difference between the respective battery blocks has become equal to or higher than a specified value (e.g. 1V), existence of an overdischarge cell is detected. In this case, a battery ECU 14 sets the SOC(state of charge) of the assembly battery 10 to a control lower limit value (e.g. 20%). Thereby an HVECU 16 controls a load 18 to place the assembly battery 10 in a chargeable state. In the case when discharge is generated, the assembly battery 10 is cut off from the load 18 by a relay 20.

A method of operating an electric vehicle with battery regeneration dependant on battery charge state

Abstract: of EP0921024An electric vehicle is controlled to conform its operation to that of a conventional internal-combustion-engine powered vehicle In some embodiments, the charging of the batteries by the auxiliary source of electricity and from dynamic braking is ramped in magnitude when the batteries lie in a state of charge between partial charge and full charge, with the magnitude of the charging being related to the relative state of charge of the battery The deficiency between traction motor demand and the energy available from the auxiliary electrical source is provided from the batteries in an amount which depends upon the state of the batteries, so that the full amount of the deficiency is provided when the batteries are near full charge, and little or no energy is provided by the batteries when they are near a discharged condition At charge states of the batteries between near-full-charge and near-full-discharge, the batteries supply an amount of energy which depends monotonically upon the charge state Charging of the batteries from the auxiliary source is reduced during dynamic braking when the batteries are near full charge Control of the amount of energy returned during dynamic braking may be performed by control of the transducing efficiency of the traction motor operated as a generator