Showing papers on "State of charge published in 1985"

Nickel-cadmium battery state-of-charge measuring method

Abstract: The terminal voltage of nickel-cadmium battery is measured while the battery is placed under a heavy discharge load during a predetermined short interval.

Hybrid Vehicle Systems Analysis

Abstract: A technique has been developed for deriving the optimal operating strategy including engine calibration for a hybrid vehicle given the vehicle hardware description, the operating cycle, emission constraints, and the relative costs of the two energy sources carried on the vehicle. This report describes the technique and presents the results of applying it to a set of electric/ICE hybrid vehicles which attempt to encompass a very wide range of powertrain choices for a 2000 lb base vehicle. Results are presented for city driving where the battery is required to end the cycle at the same state of charge as at the beginning, as well as a 100-mile mission over which it was possible to fully discharge the battery at no cost. The study indicates, for the assumptions and constraints of this particular study, the powertrain combinations which have the highest potential both for liquid fuel and for combined energy saving.

Second‐Order Harmonic in the Current Response to Sinusoidal Perturbation Voltage for Lead‐Acid Battery An Application to a State‐of‐Charge Indicator

Abstract: Distortion of the current response to sinusoidal alternating perturbation voltage has been quantitatively measured as a function of state of charge for commercially available lead-acid batteries. The input amplitude adopted here was greater than those used for ordinary impedance measurement. The distortion is represented as a power spectrum. Among higher order harmonics, that of the second one was selected for the parameter of a state-of-charge indicator. Excellent linearity was observed for the state of charge. It was also clarified that, compared to other parameters of the indicator, such as terminal voltage, impedance of fundamental tone, and concentration of sulfuric acid this parameter is less influenced by other factors during practical operation, such as discharge current and rest time.

Battery state of charge evaluator

Abstract: A microprocessor based monitoring system for the traction battery 10 of an electric vehicle evaluates the state of charge and displays it on a dashboard mounted meter 64 and interfaces with a traction motor control system 20. The battery is divided into nine 24V sub-packs. During both discharge and recharge, the battery current is integrated to obtain a value representing the charge withdrawn. During discharge, the current is adjusted to compensate for the rate of discharge. During the first part of each discharge, the state of charge is calculated from the charge withdrawn value and from a value representing the charge storage capacity of the battery 10. During the last part of discharge, the state of charge is evaluated from the voltage of the sub-pack having the lowest voltage after compensating for polarization voltage. Polarization voltage is calculated as a function of time and of battery current. The state of charge value obtained from the lowest sub-pack voltage is also used to up-date the charge storage capacity value. The maximum traction motor current is progressively limited during the last part of discharge in accordance with the state of charge.

A system for use in monitoring the state of charge of a nickel-alkaline secondary battery

Abstract: © A system for monitoring the state of charge of a nickel-alkaline secondary battery wherein the monitor cell is comprised of a sealed metal-gas cell having a nickel electrode and an oxygen counter-electrode.