Communications: electrical – Condition responsive indicating system – Specific condition
Reexamination Certificate
1998-11-25
2001-03-20
Lieu, Julie (Department: 2736)
Communications: electrical
Condition responsive indicating system
Specific condition
C340S438000, C340S455000, C454S075000, C320S104000, C180S065100
Reexamination Certificate
active
06204769
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention generally relates to a battery control system for electric automobiles, and particularly, to a battery control system for controlling a battery of an electric automobile to cope with a significant generation of hydrogen from the battery that may occur upon a charge or discharge of the battery or with a deterioration of the battery.
2. Description of Relevant Art
In the electric automobile, a battery for a strong current service is charged from a charger and, after the charge, supplies a voltage to a motor as a load, conducting a discharge current to rotate the motor so that the automobile can travel. As the automobile travels, a remaining capacity of the battery decreases and, in due course, goes below a predetermined value for a battery controller to give an alarm for prevention of an over-discharge, while controlling the charger to re-charge the battery.
The electric automobile may run down a decline, where an acceleration pedal may be released, then the motor works as a generator that provides a restoration current. The battery is charged with the restoration current, and the battery controller controls a voltage across the battery to avoid an over-charge.
The battery for strong current service may be a lead cell or a nickel hydrogen cell, and has a tendency to generate hydrogen when brought into an over-charge or over-discharge condition. Generated hydrogen may have an undesirable concentration, as it ascends and may be accumulated under a top of an associated enclosure that may communicate with a passenger room of the automobile, in which air may become hydrogen-rich to an undesirable degree.
To avoid such a hydrogen-rich state, Japanese Patent Application Laid-Open Publication No. 8-186901 has disclosed a conventional system which checks a battery voltage to detect an over-charge state and an over-discharge state, and responds to a thus detected state to drive a fan for ventilation of an automobile.
However, the battery has a long life and experiences repeated charge-to-discharge cycles. The battery ages and may deteriorate with an increased frequency of charge-to-discharge cycle, with a probable tendency to generate hydrogen when the battery is charged or discharges in an ordinary manner free of over-charge or over-discharge. In the conventional system, as the fan is driven in response to a detected overcharge or over-discharge, the automobile may have an increasing amount of hydrogen stagnant therein.
The battery may enter an abnormal state with an increasing or continued tendency to generate hydrogen, or may suffer from an irregular command of charge and/or discharge control with which the battery may generate a great amount of hydrogen, and a driver may want to be informed of a sign of such abnormality, so that he or she can take adequate measures.
SUMMARY OF THE INVENTION
The present invention has been achieved with such points in view.
It therefore is an object of the present invention to provide a system which can expel a hydrogen-rich atmosphere from an enclosed space of an electric automobile, such as in a battery enclosure or a power train carrier or passenger room communicable therewith, to hold a hydrogen gas concentration in the enclosed space under a significant level even if the battery has a tendency to generate hydrogen gas in an ordinary service, and which can immediately inform a driver of a detected abnormal concentration of hydrogen gas in the enclosed space, due such as to an abnormal state of the battery or of charge and discharge controls.
To achieve the object, a first aspect of the invention provides a battery control system for electric automobiles, comprising a detector for detecting a concentration of hydrogen gas in an enclosed space communicating with an accommodation space for accommodating a battery for driving an electric automobile, an expeller for expelling hydrogen gas from the enclosed space, a first controller for responding to the concentration of hydrogen gas detected by the detector, as the detected concentration exceeds a first significant concentration, to provide a first control signal for driving the expeller, an alarm provider for providing an alarm on an abnormality of concentration of hydrogen gas in the electric automobile, and a second controller for responding to the concentration of hydrogen gas detected by the detector, as the detected concentration exceeds a second significant concentration higher than the first significant concentration, to provide a second control signal for driving the alarm provider.
According to the first aspect, in a battery control system for electric automobiles, a detector for hydrogen concentration detection detects a concentration of hydrogen gas in an enclosed space communicating with an accommodation space for accommodating a battery for an electric automobile to be thereby powered to travel, as the battery is charged and discharges and may generate hydrogen gas. An expeller is adapted to expel hydrogen gas from the enclosed space, as a device for a forced draft or diffusion of hydrogen gas that may be generated from the battery. A first controller, which may have input thereto a value of a concentration detected by the detector and make decision as to whether or not the detected concentration value is equal to or larger than a value of a predetermined first significant concentration, responds to the concentration of hydrogen gas detected by the detector, as the detected concentration exceeds the first significant concentration, to provide the expeller with a first control signal as a drive signal for driving the expeller. An alarm provider or an alarm system is adapted to provide an alarm on an abnormality of concentration of hydrogen gas in the electric automobile, that may be in terms of a rate of the generation of hydrogen gas. A second controller, which may make decision as to whether or not the detected concentration value is equal to or larger than a value of a predetermined second significant concentration higher than the first significant concentration, responds to the concentration of hydrogen gas detected by the detector. as the detected concentration exceeds the second significant concentration, to provide the alarm provider or system with a second control signal as an alarm signal for driving the alarm provider or system.
Accordingly, an expeller is driven with a first control signal given, and an enclosed space has a lowered concentration of hydrogen gas. Even if hydrogen gas is generated from a battery in a normal charge or discharge action, as the battery may be deteriorated, or upon a temporal generation of hydrogen gas due to a sudden acceleration or deceleration for example, generated hydrogen gas is expelled and prevented such as from accumulation in the space that may be a passenger room, without an alarm to a driver, who is thus kept free from extra anxieties, when driving.
In addition, an alarm provider or system is driven with a second control signal given, for a warning of an abnormal generation of hydrogen gas to a driver and passenger(s), who can thus be immediately informed of a generation of a great amount of hydrogen gas duc to abnormality such as of a battery or at a charge and/or discharge control system and can take adequate measures.
According to a second aspect of the invention, the battery control system further comprises a third controller for responding to the concentration of hydrogen gas detected by the detector, as the detected concentration is lower than a third significant concentration lower than the first significant concentration, to provide a third control signal for canceling the first and second control signals.
According to the second aspect, a third controller, which may make a decision as to whether or not a value of a concentration of hydrogen gas detected by a detector is equal to or smaller than a value of a predetermined third significant concentration lower than a first significant concentration, responds to the concentration of hydrogen gas detected by th
Arai Yoichi
Maemoto Toshifumi
Shimoyama Kenichi
Finnegan Henderson Farabow Garrett & Dunner L.L.P.
Lieu Julie
Yazaki -Corporation
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