Method of detecting residual capacity of battery for use on electric vehicle
First Claim
1. A method of detecting the residual capacity of a battery for energizing an electric motor to propel an electric vehicle while the battery is being discharged, based on an initial value of the residual capacity of the battery upon a transition of the battery to a discharging condition and a discharge current at predetermined periods from said battery after said transition, said method comprising the steps of:
- (a) calculating a maximum output which can be produced from said battery based on the discharge current from said battery and a battery voltage while the battery is being discharged;
(b) calculating a maximum output density by dividing said maximum output by a weight of said battery and determining whether the residual capacity of the battery is virtually zero or not based on the maximum output density;
(c) calculating a degradation error corrective capacity for correcting for a change in the residual capacity due to a degradation of the battery when the residual capacity of said battery is virtually zero; and
(d) correcting the residual capacity of said battery which has been calculated based on the initial value of the residual capacity of the battery and the discharge current from said battery, with said degradation error corrective capacity, for thereby calculating the residual capacity of said battery while the battery is being discharged.
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Accused Products
Abstract
Based on the difference between a battery voltage immediately after the battery is left to stand and the battery voltage upon elapse of the period of time after the battery has been left to stand, it is determined whether the battery has been in a charge mode or a discharge mode immediately before the battery is left to stand. If the battery has been in the charge mode, then a residual capacity is determined from the battery voltage at a predetermined time. When the battery is being discharged, then a maximum battery output is calculated based on a discharge current. If the residual capacity of the battery is determined as being virtually zero based on the maximum output, then the residual capacity is corrected with a corrective capacity for correcting for a change in the residual capacity due to a degradation of the battery, thus determining the residual capacity of the required charge quantity is calculated from the detected residual capacity and a stored rated capacity of the battery, and a temperature corrective coefficient for correcting the required charge quantity is determined. The residual capacity of the battery is determined based on an actual charge quantity indicative of an integrated average charging current at predetermined periods and the charging efficiency based on battery voltage during charging.
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Citations
26 Claims
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1. A method of detecting the residual capacity of a battery for energizing an electric motor to propel an electric vehicle while the battery is being discharged, based on an initial value of the residual capacity of the battery upon a transition of the battery to a discharging condition and a discharge current at predetermined periods from said battery after said transition, said method comprising the steps of:
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(a) calculating a maximum output which can be produced from said battery based on the discharge current from said battery and a battery voltage while the battery is being discharged; (b) calculating a maximum output density by dividing said maximum output by a weight of said battery and determining whether the residual capacity of the battery is virtually zero or not based on the maximum output density; (c) calculating a degradation error corrective capacity for correcting for a change in the residual capacity due to a degradation of the battery when the residual capacity of said battery is virtually zero; and (d) correcting the residual capacity of said battery which has been calculated based on the initial value of the residual capacity of the battery and the discharge current from said battery, with said degradation error corrective capacity, for thereby calculating the residual capacity of said battery while the battery is being discharged. - View Dependent Claims (3, 5, 7)
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2. A method of detecting the residual capacity of a battery for energizing an electric motor to propel an electric vehicle while the battery is being discharged, based on an initial value of the residual capacity of the battery upon a transition of the battery to a discharging condition and a discharge current at predetermined periods from said battery after said transition, said method comprising the steps of:
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(a) detecting a battery voltage at predetermined periods while the battery is being discharged; (b) determining whether the detected battery voltage while the battery is being discharged is lower than a preset value or not; (c) determining the residual capacity of the battery as being virtually zero when the detected battery voltage while the battery is being discharged is determined as being lower than said preset value, to calculate a degradation error corrective capacity for correcting for a change in the residual capacity due to a degradation of the battery; and (d) correcting the residual capacity of said battery which has been calculated based on the initial value of the residual capacity of the battery and the discharge current from said battery, with said degradation error corrective capacity, for thereby calculating the residual capacity of said battery while the battery is being discharged. - View Dependent Claims (4, 6)
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8. A method of detecting the residual capacity of a battery for energizing an electric motor to propel an electric vehicle upon a transition of the battery to a charging condition, comprising the steps of:
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(a) detecting a residual capacity of the battery based on a battery voltage at the time the battery starts being charged, and calculating a required charge quantity from the detected residual capacity and a stored rated capacity of the battery; (b) detecting a battery temperature, and determining a temperature corrective coefficient to correct said required charge quantity with the battery temperature, based on said battery temperature; (c) calculating a target charge quantity at said battery temperature from said required charge quantity and said temperature corrective coefficient; (d) determining a charging efficiency representative of a proportion of a charging current supplied to the battery which is converted into a residual capacity, based on the battery voltage while the battery is being charged; and (e) determining an actual charge quantity from an integrated charge quantity indicative of an integrated average charging current and said charging efficiency. - View Dependent Claims (9, 10)
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11. A method of detecting the residual capacity of a battery for energizing an electric motor to propel an electric vehicle when the battery is left to stand after the battery has been either charged or discharged, comprising the steps of:
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(a) detecting a first battery voltage immediately after the battery is left to stand and a second battery voltage upon elapse of a predetermined time after the battery is left to stand, and calculating the difference between said first battery voltage and said second battery voltage; (b) determining whether the battery has been in a charging condition or a discharging condition immediately before the battery is left to stand, based on said calculated difference; (c) reading a third battery voltage corresponding to said second battery voltage from first memory means which stores said third battery voltage as a voltage which is expected to be in a stable state of the battery voltage in a manner to correspond to said second battery voltage, when the battery is determined as having been in the charging condition; and (d) reading a residual capacity of the battery corresponding to the read third battery voltage from second memory means which stores said residual capacity in a manner to correspond to said third battery voltage. - View Dependent Claims (13, 15)
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12. A method of detecting the residual capacity of a battery for energizing an electric motor to propel an electric vehicle when the battery is left to stand after the battery has been either charged or discharged, comprising the steps of:
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(a) detecting a first battery voltage immediately after the battery is left to stand and a second battery voltage upon elapse of a predetermined time after the battery is left to stand, and calculating the difference between said first battery voltage and said second battery voltage; (b) determining whether the battery has been in a charging condition or a discharging condition immediately before the battery is left to stand, based on said calculated difference; and (c) reading a residual capacity of the battery corresponding to said second battery voltage from memory means which stores said residual capacity in a manner to correspond to said second battery voltage, when the battery is determined as having been in the discharging condition immediately before the battery is left to stand. - View Dependent Claims (14, 16)
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17. A method of detecting the residual capacity of a battery for energizing an electric motor to propel an electric vehicle while the battery is being discharged, based on an initial value of the residual capacity of the battery upon a transition of the battery to a discharging condition and a discharge current at predetermined periods from said battery after said transition, said method comprising the steps of:
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(a) calculating a maximum output which can be produced from said battery based on the discharge current from said battery and a battery voltage while the battery is being discharged; (b) calculating a maximum output density by dividing said maximum output by a weight of said battery and determining whether the residual capacity of the battery is virtually zero or not based on the maximum output density; (c) calculating an integration error corrective capacity for correcting for an integration error of the discharged current from said battery, when the residual capacity of said battery is virtually zero; and (d) correcting the residual capacity of said battery which has been calculated based on the initial value of the residual capacity of the battery and the discharge current from said battery, with said integration error corrective capacity, for thereby calculating the residual capacity of said battery while the battery is being discharged. - View Dependent Claims (18, 19, 20, 21, 22, 23)
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24. A method of detecting the residual capacity of a battery for energizing an electric motor to propel an electric vehicle while the battery is being discharged, based on an initial value of the residual capacity of the battery upon a transition of the battery to a discharging condition and a discharge current at predetermined periods from said battery after said transition, said method comprising the steps of:
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(a) detecting a battery voltage at predetermined periods while the battery is being discharged; (b) determining whether the detected battery voltage while the battery is being discharged is lower than a preset value or not; (c) determining the residual capacity of the battery as being virtually zero when the detected battery voltage while the battery is being discharged is determined as being lower than said preset value, to calculate an integration error corrective capacity for correcting for an integration error of the discharge current from said battery; and (d) correcting the residual capacity of said battery which has been calculated based on the initial value of the residual capacity of the battery and the discharge current from said battery, with said integration error corrective capacity, for thereby calculating the residual capacity of said battery while the battery is being discharged. - View Dependent Claims (25, 26)
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Specification