JPH065312A - Storage battery monitoring device - Google Patents

Abstract

PURPOSE:To recognize a discharge condition by change of display contents by storing a voltage enlarged synchronously with change of an open-circuit voltage of a storage battery in a capacitor, forming an imaginary discharge curve through a resistor, and separating and outputting a voltage change width. CONSTITUTION:An open-circuit voltage of a storage battery is obtained by a serial resistor circuit 4, and it is amplified by a circuit 5 including a Zener voltage and an operation amplifier. A parallel capacitor 6 is charged to the circuit 5 through a backflow preventing element 7. The capacitor 6 absorbs a pulse voltage higher than a no-load voltage if it is generated at a load 2, and a circuit 9 impedance-converts the voltage of the capacitor 6 through the operation amplifier. At a subsequent circuit 10, display of an LED, etc., is changed in accordance with voltage change at the circuit 9. For example, the display is increased/decreased in five stages by five comparators and resistors. A circuit 11 supplies a constant voltage. The voltage of the capacitor 6 is reduced gradually through a resistor 12 to form an imaginary discharge curve, and the curve is selected by selection of values of the capacitor and resistor. The contents of a display connected to plural outputs of the circuit 10 are changed in order.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention uses the LE capacity of a storage battery as LE.
The present invention relates to a storage battery monitoring device that digitally displays D (light emitting diode), liquid crystal, etc., and particularly relates to a storage battery monitoring device that has a function of displaying the remaining capacity of the storage battery during both discharge and rest.

[0002]

2. Description of the Related Art The most common method for monitoring the capacity of a storage battery is to measure the specific gravity of the electrolyte and estimate the capacity of the storage battery from the measured specific gravity of the electrolyte. Even this method is still the most accurate. It is said to be a method. In addition to these, there are those that apply the refractive index of the electrolytic solution, those that are converted from the discharge constant pressure of the storage battery, and those that use a virtual discharge curve.

[0003]

As a method for electrically measuring the specific gravity of the electrolytic solution and displaying the specific gravity of the electrolytic solution as it is or by converting the specific gravity of the electrolytic solution into the storage battery capacity and displaying the value, a sensor such as a float is used. A method of directly inserting the liquid crystal into an electrolytic solution, converting the displacement of the float into an electric signal, amplifying it, and displaying it is considered. However, in this method, it is complicated to convert the displacement of the float into an electric signal, the dissolved oxygen becomes bubbles as the temperature rises and adheres to the surface of the float, and an error occurs. There is a problem that it is unsuitable for a mobile storage battery that receives vibration.

The method of applying the refractive index of the electrolytic solution has problems that the prism is contaminated and the error due to the change of the light amount of the light source is large, and that the apparatus itself is considerably complicated because an amplifying apparatus or the like is required. Moreover, recently, in many cases, the storage battery has been hermetically sealed and it becomes difficult to measure the specific gravity of the electrolytic solution, and such a storage battery monitoring device is now used only in a very limited part.

As a simple type of discharge meter that compensates for the above-mentioned drawbacks, one that detects the discharge pressure of a storage battery, smooths the voltage, and converts the stored value into the storage battery capacity is widely used in the United States. Has been. However, this discharge meter has a problem in that the display at the end of discharge sharply drops and the amount of electricity (Ah) cannot be correctly detected.

Separately from this, an open circuit voltage of the storage battery or a voltage obtained by subtracting a constant voltage from the open circuit voltage is obtained, capacitors to be charged by this voltage are connected in parallel via a backflow preventing element, and the internal impedance of the capacitor causes the capacitor to Voltage is attenuated to create a virtual discharge curve, the voltage based on it is impedance-converted and amplified, and connected to an LED lighting level IC etc. to change the lighting position or the number of lighting of the LED and display the capacity of the storage battery. A method is being considered. According to this method, the voltage change width due to the capacity change of the storage battery is equal to the voltage change width stored in the capacitor. However, the change in the open circuit voltage of this storage battery in actual use is as small as about 12.7V to 11.7V when using the 6-cell type, and it is necessary to move this voltage change width at the full scale of the display. . However, when a virtual discharge curve is created by attenuating the voltage recorded in the capacitor by the internal impedance of the capacitor, the virtual discharge curve may change due to variations in the internal impedance value of the capacitor and changes in the impedance value due to changes in ambient temperature. Is inevitable. For this reason,
This method, in which the change width of the open circuit voltage and the change width of the voltage stored in the capacitor are equal, has a drawback that the accuracy of the capacitance display is low.

The present invention has been made to solve the above problems, and an object thereof is to provide a highly reliable storage battery monitoring device.

[0008]

Therefore, in order to obtain a voltage obtained by dividing the open circuit voltage of the storage battery at a constant rate, the voltage detection means connected to both ends of the storage battery and the variation range of the voltage obtained by the voltage detection means are set. Amplifying means for amplifying by a certain factor, a capacitor connected in parallel to the amplifying means via a backflow prevention element, and a discharge circuit connected in parallel with the capacitor for attenuating the electric charge of the capacitor to obtain a predetermined virtual discharge curve. And a display circuit having a plurality of comparators or level ICs as outputs for converting the capacitor voltage into an impedance and changing the display composed of an LED or liquid crystal in response to the voltage change. The above problem is solved by using the device.

[0009]

In a storage battery that is intermittently discharged, such as a storage battery for an electric vehicle or an electric vehicle, the voltage at the stable peak portion of the open circuit voltage (no-load voltage) at the time of discharge suspension is the capacity of the storage battery or the electrolyte specific gravity. Has a theoretically proportional relationship with the value,
Paying attention to the fact that the voltage value of the peak portion also decreases as the capacity decreases or the electrolyte specific gravity value decreases, the storage battery monitoring apparatus according to the present invention provides a stable peak voltage of the open circuit voltage at the time of the discharge suspension. A virtual discharge curve is created by attenuating it through a discharge circuit connected in parallel with a capacitor, and an output unit is provided so that this virtual discharge curve can be displayed by a display device composed of an LED or liquid crystal. Since the voltage of the storage battery during discharge varies greatly depending on the magnitude of the discharge current, it is not possible to monitor the capacity by this discharge voltage, but by setting a virtual discharge curve, the storage battery The capacity can be monitored. When the discharge rest state is resumed, the capacitor is recharged by the voltage at the stable peak portion of the circuit voltage at the time of the rest, and the virtual discharge curve is corrected, so that accurate monitoring can be performed.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A storage battery monitoring device according to the present invention will be described in detail with reference to the drawings. In FIG. 1, 1 is a monitored storage battery (hereinafter, simply referred to as a storage battery), 2 is a load, and 3 is a load closing switch.

Reference numeral 4 denotes a circuit for obtaining an open circuit voltage of the storage battery 1, that is, a voltage obtained by dividing the storage battery voltage when the load 2 is not connected to the storage battery 1 at a constant ratio, and is connected to both ends of the storage battery. There is. Although various circuit configurations are conceivable as the circuit 4, for example, the circuit 4 may be configured by a series circuit of two resistors so as to obtain a divided voltage from between the resistors.

Reference numeral 5 is a circuit for obtaining a voltage obtained by multiplying the change width of the voltage obtained by the circuit 4 by a constant value. In this embodiment, the Zener voltage is used as a reference voltage, and the difference from the voltage obtained by the circuit 4 is set by an operational amplifier. It is used and amplified. The circuit 5 is used to expand the range of voltage change, for example, when a 6-cell storage battery 1 is used, the change in the open circuit voltage of the storage battery in actual use is as small as about 12.7V to 11.7V. This is because it is necessary to divide the vicinity of the voltage change width into an output to a display device described later and divide it into several stages. The circuit 4 is for reducing the difference from the reference voltage of the circuit 5 and increasing the amplification of the voltage change width.

Reference numeral 6 is a capacitor charged by the voltage obtained in the circuit 5, and is connected in parallel to the circuit 5 via a backflow prevention element 7 such as a silicon diode. Therefore, the capacitor 6 is charged with a voltage at which the change in the open circuit voltage of the storage battery 1 obtained in the circuit 5 is amplified by a certain factor and then changed, and the open circuit 5 is closed due to the decrease in the terminal voltage due to the connection of the load 2 to the storage battery. Even if the voltage obtained in step 2 becomes lower than the voltage at the time of charging the capacitor, the electric charge charged in the capacitor 6 is not discharged to the circuit 5 side.

Reference numeral 8 is a capacitor that absorbs a pulse 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 in the load 2 or chopper control. The circuit 9 is a capacitor that absorbs the voltage of the capacitor 6.

The circuit 9 is for impedance conversion of the voltage of the capacitor 6. Although an operational amplifier is used here, if the input impedance of the circuit 10 described later is extremely high, the circuit 10 can also serve as the input impedance.

The circuit 10 is a portion for obtaining an output for changing the display of a display device made of an LED, a liquid crystal or the like in response to a change in the voltage obtained by the circuit 9. Here, the display is sequentially increased and decreased in five steps by using five comparators and resistors, but it is also possible to adopt a display in which the display sequentially moves in accordance with the display content of the display device, and it is also possible to set the display arbitrarily. It is also possible to divide the stage into the number of and display. Also, instead of using a combination of a comparator and a resistor, L
It is also possible to replace it with an ED lighting level IC.

The circuit 11 is a constant voltage circuit for power supply such as an operational amplifier and a comparator. Here, a power regulator IC is used as a device for supplying a stable power supply voltage to the IC. However, any device may be used as long as it can obtain a constant voltage.

The voltage charged in the capacitor 6 is gradually discharged through the resistor 12, and as a result, the voltage of the capacitor 6 gradually decreases. This voltage drop of the capacitor 6 becomes a virtual discharge curve. Further, the degree of the voltage drop of the capacitor 6 can be arbitrarily adjusted by changing the capacitance of the capacitor 6 and the resistance value of the resistor 12, so that the virtual discharge curve can be arbitrarily selected. Further, the voltage drop of the capacitor 6 causes the voltage levels of the plurality of outputs of the circuit 10 to change in response to this. Therefore, if a display device including an LED or a liquid crystal is connected to the output section of the circuit 10, the display content will change sequentially. By looking at this change in the display, the voltage of the capacitor 6, and hence the open circuit voltage of the storage battery 1, can be known. Further, the loss voltage generated in the capacitor 6 is recharged and corrected by the open circuit voltage at this time when the discharging of the storage battery 1 is stopped next time. Therefore, the voltage of the capacitor 6 is always synchronized with the change in the open circuit voltage of the storage battery 1. The open circuit voltage of the storage battery 1 is E = 0.
84 + S.G. (electrolytic solution specific gravity value), it has a proportional relationship with the electrolytic solution specific gravity value and capacity, and looking at the voltage change of the capacitor 6 is the capacity of the storage battery 1 or the electrolytic solution specific gravity value. You will see the change in value. Further, R and r are resistors for limiting current, and D is a diode for preventing backflow.

As described above, in this embodiment, the expanded voltage synchronized with the change in the open circuit voltage of the storage battery 1 is stored in the capacitor 6, and the voltage of the capacitor 6 is discharged through the resistor 12 to generate a virtual discharge curve. This voltage is impedance-converted, and the voltage change width is divided into a plurality of steps and output by the circuit 10 in a plurality of stages. If an output device of the circuit 10 is connected to a display device such as an LED or liquid crystal, The discharge state of the storage battery 1 can be known by the change in the displayed content.

[0020]

As described above, the storage battery monitoring device according to the present invention does not require a sensor for measuring the specific gravity to be inserted into the storage battery as in the prior art, and also has a main circuit like the conventional Ah meter. No shunt is inserted, and no shut is inserted in the main circuit unlike the conventional Ah meter. By simply connecting to the storage battery terminal, the capacity of the storage battery can be accurately monitored even when the storage battery is left standing or discharged, and even if the open circuit voltage of the storage battery is 6 cells or less in which the actual use change width is very small. it can. Furthermore, since the number and changes of the output section can be set freely, the display connected to the output section can be used for any type of LED or liquid crystal, and the displayed contents can be displayed in a stair-like shape to display the capacity graphically. It has an excellent advantage that it can be done.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing an embodiment of a storage battery monitoring device of the present invention.

[Explanation of symbols]

1 Monitored storage battery 2 Load 4 Circuit for obtaining a voltage obtained by dividing the open-circuit voltage of the storage battery at a constant rate 5 Circuit for obtaining a voltage with a constant change width of voltage 6 Capacitor 7 Backflow prevention element 9 Impedance conversion circuit 10 Output circuit 11 Constant voltage circuit

Claims (1)

[Claims] 1. A voltage detecting means (4) connected to both ends of a storage battery to obtain a voltage divided at a constant rate from an open circuit voltage of the storage battery, and a variation range of the voltage obtained by the voltage detecting means (1). Amplifying means (5) for amplifying by a certain factor, and a capacitor (6) and a capacitor (6) connected in parallel to the amplifying means (5) via a backflow prevention element (7) to attenuate the electric charge to a predetermined virtual A discharge circuit (12) connected in parallel with a capacitor (6) to obtain a discharge curve, and impedance conversion of this capacitor voltage, and changing an indicator composed of LED, liquid crystal, etc. in response to this voltage change A storage battery monitoring device comprising: a display circuit (11) having a plurality of comparators or level ICs as an output for causing the output.