Yazaki Corporation

Ryo Kumagai

Kenichi Shimoyama

Youichi Arai

Tsutomu Saigo

Yoshihide Takada

Yoichi Arai

Brendan O'Toole

In each time slot, along with processing collected sets of amperage data and voltage data and a data on a reference current to provide a first value as an estimated residual capacity for a normal travelling, the amperage data are processed to provide a second value representative of a discharge quantity, and the second value is subtracted from the first value to provide a third value as a residual capacity for a high load condition, permitting the first value to be displayed in the normal travelling and the third value to be displayed under the high load condition, as this condition is detected by checking a significance of correlation in dispersion of the collected sets of data.

Battery residual capacity measuring system and battery residual capacity

A voltage sensor detects a terminal voltage of a battery connected to a load and a current sensor detects a current flowing through the load. A voltage-current changing tendency calculation unit reads a detected voltage and a detected current detected by the voltage sensor and the current sensor and outputs, every predetermined period of time, plural data of the detected voltage and the corresponding detected current as dispersed data. A voltage-current approximating line calculation unit inputs the dispersed data and determines, based on the dispersed data, a voltage-current approximating linear function each time the predetermined period of time. A battery remaining capacity calculation unit determines, each time the voltage-current approximating linear function is determined, a remaining capacity of the battery based on the voltage-current approximating linear function. Particularly the voltage-current approximating line calculation unit determines the voltage-current approximating linear function by applying a method of least squares to the plural data of the voltage and the corresponding current of the dispersed data.

Battery remaining capacity measuring device

The apparatus and method of the present invention measure the remaining capacity of a battery connected to a fluctuating load. The apparatus senses dispersive terminal voltages and dispersive discharge currents from the battery, and samples the sensed terminal voltages and discharge currents. On the basis of the sampled terminal voltages and discharge currents, the apparatus calculates a watt-hour value of the battery for a predetermined time interval, and checks whether the calculated watt-hour value reaches a predetermined value. If the calculated watt-hour value reaches the predetermined value, the apparatus calculates an approximate linear function indicative of a trend of the sampled terminal voltages and discharge currents, and calculates a voltage corresponding to a reference discharge current in accordance with the calculated approximate linear function as a remaining capacity voltage. The apparatus then converts the calculated remaining capacity voltage into an ordinate position on a two-dimensional display screen, and a calculated total watt-hour value into an abscissa position on the same display screen, and displays the positions in the form of a dot curve.

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Shizuoka-ken, Japan

Ryo Kumagai