JPH0447787B2 - - 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 these reasons, storage battery monitoring devices based on the above-mentioned principle are currently only being applied 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, this discharge meter still has the problem that the display at the end of discharge drops rapidly and is not proportional to the amount of electricity (Ah).

The present invention is a storage battery monitoring device that solves the above-mentioned problems, that is, a voltage detection device 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 voltage detection device that uses the voltage detection device. To memorize the voltage,
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
An indicator consisting of an LED lighting level IC and a plurality of LEDs connected to the output of the LED lighting level IC, which displays the discharge status of the storage battery by sequentially moving the lighting in response to a virtual discharge curve. The present invention provides a storage battery monitoring device comprising the following.

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 by moving the lighting of the display. 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 storage battery to be monitored (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 certain voltage from the storage battery voltage when the load 2 is not connected to the storage battery 1; Connected to both ends. The circuit 4 may have various circuit configurations, but for example, it may be constructed from a series circuit of a voltage regulator diode and a resistor, and a configuration in which a constant voltage is subtracted by the voltage regulator diode and the remaining voltage can be set from both ends. You may. The reason why the circuit 4 is provided is that, 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 51 V to 47 V, and the LED lighting will be described below around this voltage change range. This is because the input range of this level IC is to operate a display device consisting of multiple LEDs at full scale. 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, Even if the obtained voltage is lower than the voltage at the time of charging the capacitor, the 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. 8 is an LED lighting level IC that converts the impedance of the voltage of the capacitor 5 and amplifies it, and the input pin of this IC is connected to the capacitor 5 in parallel. 9 is LED lighting IC
In response to a drop in the input voltage of the LED lighting level IC 8, that is, a drop in the voltage of the capacitor 5,
The LED lights are configured to move sequentially. Reference numeral 10 denotes a moving circuit that sequentially moves the lighting of a plurality of LEDs constituting the display 9, and is composed of a diode 13 and a constant voltage diode 14 connected between the positive terminals of each LED. The input impedance of the LED lighting level IC 8 is very high, and the output pins are sequentially turned on at a voltage proportional to the voltage without discharging the charge charged in the capacitor 5. Then, the plurality of LEDs of the display 9 are sequentially turned on by the conduction of the output pin. In this case, the current flowing through the LED is I,
If the number of LEDs is n and the storage battery voltage is 50V, the power consumption used in the device is n x I x 50 (W)
Therefore, the circuit cannot be sealed due to the heat generated within the device. Furthermore, it is dangerous to operate the device all the time because a battery with a small capacity may cause large self-discharge. This has created a need for circuits with low power consumption. Therefore, this example
A moving circuit 10 for moving the lighting of the LED is provided to reduce power consumption. That is,
Connected to each output pin of level IC8 for LED lighting.
Insert diode 13 or constant voltage diode 14 between the positive of the LED and set the level for LED lighting.
The output pin of IC8 is an LED lighting level.If pins ₁ to 5 are made conductive as the input voltage of IC8 increases, only LED ₁ will turn on when output pins _{1 to 5 are} in the OFF state, and output pin ₁ will turn on. When turned on, only LED ₂ is on
Similarly, when output pins ₁ to ₅ are turned on, only LED ₆ is turned on. In this way, when the level IC input for LED lighting (= capacitor voltage = storage battery open-circuit voltage = storage battery capacity) decreases, the LED lighting sequentially moves from LED ₆ to LED ₁ , and at that LED lighting position, the storage battery capacity increases. can be determined. in this case
The current value flowing into the LEDs is 1/n of that when all the LEDs are turned on, and the amount of heat generated within the device is also small.This device can be sealed compactly and can also be applied to monitoring devices for small-capacity storage batteries.

In addition, the voltage of the capacitor 5 indicates the no-load voltage before discharge of the storage battery 1 unless there is a leakage voltage, but since there is a leakage current in the capacitor, the capacitor 5 gradually discharges, although it is very small. 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 across the capacitor 5 is indicated by sequentially shifting the lighting of a plurality of LEDs on the display 9 through the LED lighting level IC 8 in response to the voltage drop across the capacitor 5. Therefore, by looking at the lighting positions of the 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 will be reduced the next time the storage battery 1 stops discharging.
It is charged again and corrected by the open circuit voltage at this time. Therefore, the voltage of capacitor 5 is always equal to that of storage battery 1.
The voltage is close to the open circuit voltage of . Note that the open circuit voltage of the storage battery 1 has a proportional relationship with the electrolyte specific gravity value and capacity, as expressed by the approximate formula E = 0.84 + SG (electrolyte specific gravity value), and the voltage of the capacitor 5 can be detected. is to detect the capacity of the storage battery 1 or the electrolyte specific gravity value. Also 11 is
A constant voltage diode 12 is provided to expand the input voltage of the LED lighting level IC 8, and is a constant voltage diode 12 for ensuring that the power supply voltage of the LED lighting level IC 8 falls within a predetermined range.

As described above, in this embodiment, the storage battery 1
The open circuit voltage of is stored in the capacitor 5, and the voltage of this capacitor 5 is discharged through the internal impedance of the LED lighting level IC 8 to convert the impedance and 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 lighting position of the LED. Therefore, simply by connecting this device to the storage battery 1, the discharge state of the storage battery 1 can be known from the lighting position of the LED on the display 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 can be easily distinguished because it is displayed by the lighting position of the LED, and it also has excellent advantages such as low power consumption and the ability to make the device compact.

[Brief explanation of the drawing]

The figure is a circuit diagram showing an embodiment of the storage battery monitoring device of the present invention. 1... Storage battery to be monitored, 2... Load, 4... Voltage detection circuit for obtaining a 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.

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 IC8 for LED lighting connected to the capacitor 5 to set it as a curve, and a level IC8 for LED lighting to display the discharge state of the storage battery by sequentially moving the lighting in response to the virtual discharge curve. A storage battery monitoring device comprising: an indicator 9 consisting of a plurality of LEDs connected to an output;