Electricity: battery or capacitor charging or discharging – Battery or cell discharging – With charging
Reexamination Certificate
2000-03-09
2001-02-20
Wong, Peter S. (Department: 2838)
Electricity: battery or capacitor charging or discharging
Battery or cell discharging
With charging
C320S130000
Reexamination Certificate
active
06191558
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a junction box for connecting a power supply to a load and a battery controller provided inside thereof, and more particularly to a battery controller capable of measuring a remaining capacity of each of a low voltage battery and a high voltage battery at the same time and further control timing for charging these batteries.
2. Description of the Related Art
Recently, some types of vehicles contain a high voltage battery of 36 V and a low voltage battery of 12 V. In such a vehicle, charging of the high voltage battery and low voltage battery is controlled by a battery controller provided in the junction box, which connects a vehicle power supply to its load.
The aforementioned high voltage battery is charged with 42 V by an alternator connected to an engine. Then, electric power from this high voltage is supplied to the junction box. The voltage from this high voltage battery is supplied to the load. The junction box includes a DC-DC converter for converting a voltage from the high voltage battery to a low voltage of DC14 V. This DC14 V voltage is supplied to the load and further the low voltage battery so that the low voltage battery is charged.
Generally, the junction box which connects a vehicle power supply to the load is disposed nearest the power supply. It is preferable that the remaining capacity of each of the low voltage battery and high voltage battery is obtained within this junction box.
However, the main role of a conventional battery controller provided in the junction box is to control charging of electric power to the high voltage battery and low voltage battery.
That is, the conventional battery controller has a problem that although it is disposed at a position enabling to measure the remaining capacities of both the batteries accurately, that battery controller does not measure the remaining capacity.
A method for estimation of the remaining capacity of the battery, which has been carried out at other place than the junction box conventionally is based on current accumulation method. That is, according to this method, a preliminarily charged electric amount is known and an amount of current that has already flown is subtracted from that original amount. However, this method is not capable of coping with a case where the battery is replaced during use.
Further, the conventional vehicle's remaining capacity measuring method is measurement of the remaining capacity of a single kind of the battery, and therefore, there is a problem that the conventional measuring method cannot measure the remaining capacities of plural kinds of the batteries which are often seen in recent vehicles.
SUMMARY OF THE INVENTION
Accordingly, the present invention has been achieved to solve the above problems, and therefore, it is an object of the invention to provide a battery controller having a remaining capacity measuring function capable of measuring a remaining capacity of each battery in a junction box accurately even if plural kinds of batteries are loaded on a vehicle and some of the batteries are replaced.
To achieve the above object, there is provided a battery controller contained in a junction box which is provided between a high voltage battery and a load and includes a high voltage system portion which receives a predetermined high voltage from the high voltage battery and supplies to the load and a low voltage system portion which generates a predetermined low voltage based on the predetermined high voltage and supplies to a low voltage battery and the load, the battery controller comprising: a remaining capacity measuring means for collecting predetermined plural pairs of voltage value and current value for each of the high voltage system portion and the low voltage system portion, obtaining an approximate straight line on current-voltage coordinates based on the predetermined plural pairs of the data according to least square method and then obtaining a voltage value based on the approximate straight line and a predetermined current value so as to estimate a remaining capacity of each of the high voltage battery and the low voltage battery; and a means for dispatching an instruction for charging the high voltage battery and the low voltage battery when it is determined that the remaining capacity of each of the high voltage battery and the low voltage battery estimated by the remaining capacity measuring means is below a predetermined value.
According to a preferred embodiment of the present invention, the remaining capacity measuring means collects predetermined plural pairs of the voltage value and the current value for each of the high voltage system portion and the low voltage system portion, averages each of the voltage value and the current value so as to obtain a pair of averaged voltage value and averaged current value, and repeats the processing until a predetermined number of each of the averaged voltage value and the averaged current value is collected so as to obtain an approximate straight line on the current-voltage coordinates according to the least square method, based on data on the predetermined number of pairs of the averaged voltage value and the averaged current value.
Further, to achieve the above object, according to another aspect of the invention, there is provided a junction box provided between a high voltage battery and a load, on which a predetermined high voltage is applied from a high voltage battery, comprising: a high voltage system portion which receives a high voltage from the high voltage battery and supplies to the load; a low voltage system portion which generates a predetermined low voltage based on the predetermined high voltage and supplies to a low voltage battery and the load; a high voltage system power component detecting means for detecting a voltage value and a current value in the high voltage system portion; a low voltage system power component detecting means for detecting a voltage value and a current value in the low voltage system portion; a high voltage battery remaining capacity measuring means for collecting predetermined plural pairs of voltage and the current value based on the voltage value and current value detected by the high voltage system power component detecting means, obtaining an approximate straight line on current-voltage coordinates according to least square method based on the predetermined plural pairs of the data, and obtaining a voltage value according to the approximate straight line and a predetermined current value so as to estimate a remaining capacity of the high voltage battery; a low voltage battery remaining capacity measuring means for collecting predetermined plural pairs of voltage value and current value based on the voltage value and current value detected by the low voltage system power component detecting means, obtaining an approximate straight line on current-voltage coordinates according to least square method based on the predetermined plural pairs of the data, and obtaining a voltage value according to the approximate straight line and a predetermined current value so as to estimate a remaining capacity of the low voltage battery; and a means for dispatching an instruction for charging the high voltage battery and the low voltage battery when it is determined that the remaining capacity of each of the high voltage battery and the low voltage battery estimated by the high voltage battery remaining capacity measuring means and the low voltage battery remaining capacity measuring means is below a predetermined value.
The nature, principle and utility of the invention will become more apparent from the following detailed description when read in conjunction with the accompanying drawings.
REFERENCES:
patent: 5717310 (1998-02-01), Sakai et al.
patent: 5796175 (1998-08-01), Itoh et al.
patent: 5952813 (1999-09-01), Ochiai
patent: 9-128080 (1997-05-01), None
Arai Yoichi
Satake Syuji
Finnegan Henderson Farabow Garrett & Dunner L.L.P.
Luk Lawrence
Wong Peter S.
Yazaki -Corporation
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