JPH0444707B2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention is a storage battery monitoring device that digitally displays the remaining capacity of a storage battery using LEDs (light emitting diodes), etc., and in particular has the function of displaying the remaining capacity of a storage battery whether it is discharging or not. The present invention relates to a storage battery monitoring device equipped with a storage battery monitoring device.

When monitoring the capacity of a storage battery, the most common method is to measure the specific gravity of the electrolyte and then estimate the battery capacity from the measured specific gravity of the electrolyte, and this method is still considered the most accurate method. .

Conventionally, for this purpose, the specific gravity of the electrolyte was measured electrically,
To display the electrolyte specific gravity value as is or by converting the electrolyte specific gravity value into capacity, a sensor consisting of a float or the like is inserted directly into the electrolyte, converting the displacement of the float into an electrical signal, amplifying it, and displaying the electrolyte solution. Methods of displaying it as a specific gravity value or capacity have been considered. However, with this method, converting the displacement of the float into an electrical signal is complicated, and when the temperature rises, dissolved oxygen forms bubbles and adheres to the surface of the float, causing errors and temperature conversion. The problem is that it is unsuitable for mobile storage batteries, which are also subject to vibration. A method that uses the refractive index of the electrolyte has also been considered, but this method also has the problems of dirty prisms, large errors due to changes in the light intensity of the light source, and the need for an amplification device, making the device itself quite complex. There is. As described above, many problems remain with any of the conventionally devised methods. For this reason, the storage battery monitoring device based on the above-mentioned principle is currently being applied only to a limited number of areas.

In addition, a simple discharge meter that compensates for the above-mentioned drawbacks is a monitoring device that detects the discharge voltage of a storage battery, smoothes the voltage, and converts the memorized value into the storage battery capacity, which is widely used in the United States. However, with this discharge meter, the display at the end of discharge rapidly decreased, and the amount of electricity
There remains a problem that is not proportional to Ah.

The present invention solves the above-mentioned problems.The present invention provides voltage detection means connected to both ends of the storage battery to obtain a voltage obtained by subtracting a constant voltage from the open circuit voltage of the storage battery, and a method for storing the voltage obtained by the voltage detection means. of,
A capacitor connected in parallel to the voltage detection means via a backflow prevention element, and a capacitor having a predetermined internal impedance, which attenuates the charge of the capacitor, converts the impedance of the voltage based on it, amplifies it, and sets it as a virtual discharge curve. , connected to the capacitor
A level IC for LED lighting, and a level IC for displaying the discharge status of the storage battery by turning off the lights sequentially in response to a virtual discharge curve.
The present invention provides a storage battery monitoring device including a display device made up of a plurality of LEDs connected to the output of an LED lighting level IC.

That is, the present invention provides that in a storage battery that is discharged intermittently, such as a storage battery for an electric vehicle or an electric vehicle, the stable peak voltage of the open circuit voltage (no-load voltage) at the time of discharging pause is determined by the capacity of the storage battery or Focusing on the fact that there is a theoretically proportional relationship with the electrolyte specific gravity value, and that the voltage value at the peak portion decreases as the capacity decreases or the electrolyte specific gravity value decreases, we investigated the stability of the open circuit voltage during the pause in discharge. The peak voltage of the LED is stored in a capacitor, and the voltage of this capacitor is discharged through the internal impedance of the LED lighting level IC to convert the impedance and create a virtual discharge curve.This virtual discharge curve is then connected to multiple LEDs. The display is displayed according to the number of lights lit. In addition, the voltage during discharge of a storage battery changes significantly depending on the magnitude of the discharge current, so the capacity cannot be monitored based on the voltage during discharge, but the hypothetical discharge curve described above can be used to This allows the capacity of storage batteries to be monitored. Furthermore, when the discharge rests again, the capacitor is charged again with the stable peak voltage of the open circuit voltage at the time of rest, and the virtual discharge curve is corrected, allowing accurate monitoring. It is something.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The storage battery monitoring device of the present invention will be specifically described below using an embodiment shown in the drawings.

In the figure, 1 is a monitored storage battery (hereinafter simply referred to as a storage battery), 2 is a load, and 3 is a load input switch. 4 is a voltage detection circuit (hereinafter abbreviated as circuit) for obtaining the open circuit voltage of the storage battery 1, that is, the voltage obtained by subtracting a constant voltage from the storage battery voltage when the load 2 is not connected to the storage battery 1; Connected to both ends. Various circuit configurations can be considered for the circuit 4, but for example, it may be constructed from a series circuit of a constant voltage diode and a resistor, and a constant voltage is subtracted by the constant voltage diode, and the remaining voltage is obtained from both ends of the resistor. may be configured. In addition, the circuit 4 is provided because, for example, when a 24-cell storage battery 1 is used, the change in the open circuit voltage of this storage battery in actual use is small, about 51V to 47V, and the LED lighting will be described below around this voltage change range. This is to operate a display device consisting of multiple LEDs at full scale as an input range for a commercial level IC. Reference numeral 5 denotes a capacitor charged with the voltage obtained by the circuit 4, and this capacitor is connected in parallel to the circuit 4 via a backflow prevention element 6 such as a silicon diode. Therefore, the capacitor 5 is charged with the stable peak voltage remaining after subtracting a constant voltage from the open circuit voltage of the storage battery 1 obtained in the circuit 4, and due to the decrease in the terminal voltage due to the connection of the load 2 of the storage battery 1, the capacitor 5 is charged in the circuit 4. Even if the obtained voltage is lower than the voltage when charging the capacitor,
The electric charge charged in the capacitor 5 is not discharged to the circuit 4 side. 7 is a capacitor that absorbs a pulse voltage higher than the no-load voltage when a pulse voltage higher than the no-load voltage is generated at the terminal of the storage battery 1 due to regenerative braking or chopper control in the load 2. Reference numeral 8 denotes an LED lighting level IC for impedance conversion and amplification of the voltage of the capacitor 5, and the input pin of this IC is connected in parallel to the capacitor 5. 9 is
Multiple units connected to the output of LED lighting IC8
This is a display section made of LEDs. The input impedance of the LED lighting level IC 8 is very high.
A plurality of LEDs of the display section 9 are sequentially turned on with a voltage proportional to the voltage without discharging the electric charge charged in the capacitor 5, and the LEDs are turned on.
The number of lights lit indicates the open circuit voltage of the capacitor and, in turn, the storage battery. As long as there is no leakage voltage, the voltage across the capacitor 5 indicates the no-load voltage before the storage battery 1 is discharged. However, since there is a leakage current in the capacitor, the capacitor 5 gradually discharges, albeit very slightly. As a result, the voltage of capacitor 5 gradually decreases. This voltage drop across the capacitor 5 becomes a virtual discharge curve. Furthermore, since the degree of voltage drop across the capacitor 5 can be arbitrarily adjusted by changing the capacitance of the capacitor 5, the virtual discharge curve can also be arbitrarily selected. Furthermore, the voltage drop of capacitor 5 is LED
The display unit 9 has multiple lights through the lighting level IC 8.
This is displayed by sequentially turning off the LEDs in response to the voltage drop across the capacitor 5. Therefore, by looking at the number of lit LEDs on the display section 9, the voltage of the capacitor 5 and, in turn, the open circuit voltage of the storage battery 1 can be known. Furthermore, the loss voltage generated in the capacitor 5 is corrected by being charged again the next time the storage battery 1 stops discharging, using the open circuit voltage at this time.
Therefore, the voltage of the capacitor 5 is always close to the open circuit voltage of the storage battery 1. In addition, storage battery 1
The open-circuit voltage of is proportional to the electrolyte specific gravity value and capacity, as expressed by the approximate formula E = 0.84 + SG (electrolyte specific gravity value), and detecting the voltage of the capacitor 5 is the same as that of the storage battery 1. The capacity or electrolyte specific gravity value will be detected. In addition, 10 is a constant voltage diode provided to expand the input voltage of the LED lighting level IC 8, 11 is a constant voltage diode for establishing the power supply of the LED lighting level IC 8, R
and r is a current limiting resistor.

As described above, in this embodiment, the storage battery 1
The open circuit voltage of the capacitor 5 is stored in the capacitor 5, and the voltage of the capacitor 5 is discharged through the internal impedance of the LED lighting level IC 8 to convert the impedance to create a virtual discharge curve, and each point of this virtual discharge curve is displayed on the display 9. multiple pieces of
This is displayed by the number of lit LEDs. Therefore, simply by connecting this device to the storage battery 1, the discharge state of the storage battery 1 can be known from the number of LEDs lit on the display section 9.

As described above, the storage battery monitoring device of the present invention does not require the insertion of a sensor for measuring specific gravity into the storage battery as in the conventional case, nor does it require the insertion of a shunt into the main circuit as in the conventional Ah meter. Just by connecting to the storage battery terminal, you can accurately monitor the storage battery capacity and electrolyte specific gravity even when the storage battery is left unused or discharged.
It has the advantage that it can be easily distinguished because it is displayed by the number of lit LEDs.

[Brief explanation of the drawing]

The figure is a circuit diagram showing an embodiment of the storage battery monitoring device of the present invention. DESCRIPTION OF SYMBOLS 1... Storage battery to be monitored, 2... Load, 4... Voltage detection circuit for obtaining the voltage obtained by subtracting a constant voltage from the open circuit voltage of the storage battery, 5... Capacitor, 6...
Backflow prevention element, 8...Level IC for LED lighting, 9
...Display section.

Claims (1)

[Claims] 1. Voltage detection means 4 connected to both ends of the storage battery 1 to obtain a voltage obtained by subtracting a constant voltage from the open circuit voltage of the storage battery 1; and To store the voltage obtained by the voltage detection means 4. A capacitor 5 which has a predetermined internal impedance is connected in parallel to the voltage detection means 4 via a reverse current prevention element 6, and the charge of the capacitor 5 is attenuated, and the voltage based on the capacitor 5 is impedance-converted and amplified to generate a virtual discharge. A level IC 8 for LED lighting connected to the capacitor 5 for setting as a curve, and an LED lighting level IC 8 for displaying the discharge state of the storage battery by turning off the lights sequentially in response to the virtual discharge curve.
A storage battery monitoring device comprising: an indicator 9 made up of a plurality of LEDs connected to the output of an LED lighting level IC 8;