JPH0651886U - Battery remaining capacity detector - Google Patents

Abstract

(57) [Summary] [Object] An object of the present invention is to provide a battery remaining capacity detection device that accurately detects the remaining capacity of the battery regardless of whether the vehicle is running or stopped. [Structure] Bus 1 connecting generator 14 and battery 15
Is connected to a variable resistor 3, the bus bar 1 is connected to a positive terminal of a battery 15 via a resistor RS, and a battery capacity detection circuit 6 for inputting a voltage before and after the resistor RS is provided. The current flowing through the resistance RS of the capacitance detection circuit 6 is measured, the variable resistance 3 is controlled, the current value flowing through the resistance RS is held at a constant value, the battery voltage is measured, and the battery voltage and the battery capacity A display unit for calculating the remaining capacity of the battery 15 from the map showing the relationship and displaying the remaining capacity is provided.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a battery remaining capacity detecting device for detecting a remaining capacity of a vehicle battery.

[0002]

[Prior art]

 For example, as shown in FIG. 5, a current detection resistor RS is provided on a bus bar 1 that connects a generator 14 of an automobile electric system and a battery 15, and a battery capacity detection circuit 6 is connected to both ends of the bus to detect the battery capacity. Techniques for detecting are known.

When an attempt is made to detect the remaining capacity of the battery when the engine is idling, the current in the field coil is cut off to stop the power generation, the charging current to the battery 15 is stopped, and the remaining capacity is maintained in that state. Is measured, but the engine speed increases rapidly because the generator is unloaded.

Therefore, for example, Japanese Utility Model Publication No. 3-42386 is disclosed in which the remaining capacity is detected only when the engine shaft and the axle are connected.

[0005]

[Problems to be solved by the device]

 However, the above technique has a problem that the remaining capacity of the battery cannot be detected when the engine is idling and the discharge current used for detecting the remaining capacity is not constant, resulting in a large detection error.

Therefore, an object of the present invention is to provide a battery remaining capacity detection device that accurately detects the remaining capacity of the battery regardless of whether the vehicle is running or stopped.

[0007]

[Means for Solving the Problems]

 According to the present invention, a variable resistor is connected to the bus connecting the generator and the battery, the positive terminal of the battery is connected to the bus via the resistor RS, and the voltage before and after the resistor RS is input. A battery capacity detection circuit is provided, and the detection circuit measures the current flowing through the resistance RS of the battery capacity detection circuit, controls the variable resistance, and holds the current value flowing through the resistance RS at a constant value. Is provided, display means for calculating the remaining capacity of the battery from the map showing the relationship between the battery voltage and the battery capacity, and displaying the remaining capacity is provided.

[0008]

[Action]

 In the battery remaining capacity detecting device configured as described above, since the current value for measuring the remaining capacity of the battery is measured as a constant value, the remaining capacity can be detected and displayed with high accuracy regardless of the output of the generator.

In addition, the inspection can be performed at any time, whether the vehicle is running, idle, or stopped.

[0010]

【Example】

 Hereinafter, embodiments of the present invention will be described with reference to the drawings.

In the drawings, the same members are designated by the same reference numerals, and the description thereof is omitted.

In FIG. 1, a generator 14 and a battery 15 are connected by a bus 1. The bus 1 is connected to one end of a load 2 and a variable resistor 3 of a vehicle, respectively, and one end of the variable resistor 3 and the battery 15 are connected. A resistor RS is interposed between the positive and negative points.

The central terminal of the variable resistor 3 is connected to the variable resistance control signal generating D / A converter 7 of the battery capacity detection circuit 6, and both ends of the resistor RS are connected to the resistor RS in the electric circuit 4. The IB measuring A / D converter 8 and the electric circuit 5 are connected to the battery voltage measuring A / D converter 9 and the IB measuring A / D converter 8.

The variable resistance control signal generating D / A converter 7, the IB measuring A / D converter 8 and the battery voltage measuring A / D converter 9 store the RAM 16 and the battery voltage-capacity map data, respectively. And a ROM 17 for storing the control program code, and also connected to the remaining capacity display device 12 and the over-discharge alarm device 13 via the drivers 10 and 11.

The alarm stop confirmation switch 18 is connected to the driver 11.

The operation will be described below with reference to FIG.

First, the battery current IB is measured and the variable resistance absorption current is calculated (see steps S 1, S 2 and FIG. 3). It is determined whether the absorption current is within the capacity of the variable resistor 3 (step S3). If NO, the process returns, and if YES, the variable resistor 3 is energized and the variable resistor 3 is controlled so that it becomes Imeas (a constant value) (see step S4 and FIG. 3). The battery voltage is measured, the energization of the variable resistor is stopped, and the remaining capacity is calculated from the map (see steps S5, S6, S7 and FIG. 4). The remaining capacity is displayed on the remaining capacity display device 12 (step S8). It is judged whether or not it is over-discharged (step S9), the control is ended if NO, and if YES, an over-discharge alarm is output to the over-discharge alarm device 13 (step S10) and the control is ended.

[0018]

[Effect of device]

 Since the present invention is configured as described above, it is possible to accurately display the remaining battery capacity regardless of the output of the generator. In addition, it is convenient because it can be inspected at any time during running and idle, and the current flowing through the variable resistor is extremely short, so there is almost no effect on the battery.

[Brief description of drawings]

FIG. 1 is a configuration block diagram of a detection device according to an embodiment of the present invention.

FIG. 2 is a foot chart diagram of the control of FIG.

FIG. 3 is a diagram showing a relationship between a battery current and a measured current during measurement.

FIG. 4 is a map diagram showing a relationship between battery voltage and battery capacity.

FIG. 5 is a diagram showing an example of an electrical system provided with a conventional battery capacity detection circuit.

[Explanation of symbols]

 1 ... Bus bar 3 ... Variable resistance 6 ... Battery capacity detection circuit 7 ... Variable resistance control signal generation D / A converter 8 ... IB measurement A / D converter 9 ... Battery voltage measurement A / D converter

Claims (1)

[Scope of utility model registration request] 1. A battery capacity for connecting a variable resistor to a bus connecting a generator and a battery, connecting a positive terminal of a battery to the bus via a resistor RS, and inputting a voltage before and after the resistor RS. A detection circuit is provided, the detection circuit measures the current flowing through the resistance RS of the battery capacity detection circuit, controls the variable resistance, holds the current value flowing through the resistance RS at a constant value, and measures the battery voltage. A battery remaining capacity detection device comprising: a display unit that calculates the remaining capacity of the battery from a map showing the relationship between the battery voltage and the battery capacity and displays the remaining capacity.