JPH10185968A - Electric circuit for detecting voltage - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inexpensive electric circuit for detecting voltage which is for preventing degradation of rechargeable battery, detecting small voltage by a single element and having charging function. SOLUTION: Between a positive terminal 3 and negative terminal 2 of a rechargeable battery 1, connected in series are a fixed contact 10a and a fixed contact 10b of a relay 4, a resistor 12 for setting holding limit current and coil 5 of the relay 4. The voltage between two electrodes 2 and 3 of the battery 1 is divided into the coil 5 of relay 4 and the resistor 12 for setting holding limit current to lower the voltage loaded on the coil 5 of the relay 4. On the other hand, by connecting a resistor 13 for discharge current setting in parallel between the fixed contact 10b of the relay 4 and the negative terminal 2 of the rechargeable battery 1, discharging rate can be controlled so as not to be instantaneous short circuit during the discharge. For improving the accuracy of set value of them, each of resistors 12 and 13 is made semifixed resistor and made to be controllable. In the case a fully discharged battery is loaded to this electric circuit, a button 11 for discharging by manual can be added to a relay 6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a voltage detecting electric circuit, and more particularly to a voltage detecting electric circuit having a simple structure suitable for a small electric product having a charging function.

[0002]

2. Description of the Related Art Conventionally, in order to detect a very small voltage of 1 V or less, a device using an active element requires a separate power supply, and it is necessary to use many components to form a complicated circuit configuration.
On the other hand, in the case of a meter or the like, the human eye must intervene to detect the voltage, and there is no device that can detect and control with a single element. For this reason, in a small electric product having a charging function, there is a shortage of space for incorporating a voltage detection circuit or an expensive product, so that some charging devices have omitted the voltage detection circuit. In such a case, there is a possibility that the charging capability may be reduced due to repetition of charging in an insufficient discharge state and overdischarge.

[0003]

In order to charge a charged battery, when the battery is a nickel cadmium battery, even if the battery is overcharged over a specified voltage or charged at a time when the voltage does not drop to a discharge stop voltage, a memory phenomenon occurs. The ability is reduced. On the other hand, discharging to a complete discharge at a voltage equal to or lower than the discharge stop voltage is also considered to adversely affect the nickel cadmium battery. The problem of the present invention addresses this problem,
An object of the present invention is to provide an inexpensive voltage detection electric circuit for preventing deterioration of a rechargeable battery. It is another object of the present invention to provide a voltage detecting electric circuit which has a charging function by detecting a minute voltage with a single element.

[0004]

The above object of the present invention is attained by the following constitution. That is, the voltage detection electric circuit detects not only the relay-specific holding limit voltage but also an arbitrary voltage by using the holding limit voltage of the relay for voltage detection and connecting a resistor in series to the relay. By detecting the discharge voltage of the rechargeable battery as the arbitrary voltage, discharge control of the rechargeable battery can be performed.

Further, according to the present invention, a relay is connected between a positive terminal and a negative terminal of a rechargeable battery, a holding limit current setting resistor is arranged in series with a wire of the relay. A voltage detection electric circuit in which a discharge current setting resistor is connected in parallel with the setting resistor is also included.

[0006] A relay is connected between the positive terminal and the negative terminal of the rechargeable battery, a holding limit current setting resistor is arranged in series with the wire of the relay, and the voltage between the two poles of the charging ground is connected to the relay and the resistor. To reduce the voltage applied to the relay. On the other hand, by connecting a discharge current setting resistor in parallel to the relay and the holding limit current setting resistor, the discharge speed is adjusted so that an instantaneous short circuit does not occur during discharging.

[0007] In order to improve the accuracy of the set values of these resistors, each resistor may be a semi-fixed resistor and may be adjustable. When a sufficiently charged battery is attached to this electric circuit, a button for manual discharging can be added to the relay.

Further, according to the present invention, the battery is charged after the battery is once discharged to the discharge stop voltage, and the discharge circuit is held during the discharge to the predetermined voltage, and the discharge circuit is automatically activated when the voltage drops to the predetermined voltage. An electric circuit for detecting a voltage to be cut off is also included.

In the voltage detection electric circuit, the discharge circuit is held to a predetermined voltage during discharging in order to prevent a memory phenomenon of the rechargeable battery due to incomplete discharge exceeding the discharge stop voltage.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a voltage detecting circuit according to the present invention will be described. As shown in FIG. 1, a rechargeable battery 1 to be charged is mounted on a discharger via a negative terminal 2 and a positive terminal 3. A relay 4 for turning on / off the discharger is fixed to a magnetic pole 6 around which a coil 5 is wound, an iron piece 7 attracted to the magnetic pole 6, and a point A of a component of the discharger to which the iron piece 7 is attached. It comprises a leaf spring 8 of a metal plate having elasticity and a movable contact 9 mounted on the same surface as the iron piece 7 at the tip of the leaf spring 8.

Accordingly, when the iron piece 7 moves due to the deflection of the leaf spring 8, the movable contact 9 also moves in the same direction. The movable contact 9 comes into contact with the fixed contacts 10a and 10b due to the deflection of the leaf spring 8.

A push button 11 for pressing the leaf spring 8 to contact the movable contact 9 and the fixed contacts 10a and 10b to turn on the circuit may be integrated with the leaf spring 8 or a case of the relay 4 or It may be mounted vertically on the entire housing of the apparatus.

When the rechargeable battery 1 drops to the discharge end voltage during discharging, the holding limit voltage setting resistor 12 for setting the release of the iron piece 7 by the magnetic pole 6 and the discharge current setting resistor 13 for the rechargeable battery 1 are fixed. Connection point 1 with contact 10b
4 is provided on the opposite side of the loop-shaped coil 5 for the magnetic pole 6 through the intermediary 4.

The holding limit voltage setting resistor 12 controls the coil 5 so that when the voltage of the rechargeable battery 1 drops to the discharge end voltage, the force of the magnetic pole 6 to attract the iron piece 7 becomes equal to the return force of the leaf spring 8. And a semi-fixed resistor. Further, the discharge current setting resistor 13 is a semi-fixed resistor provided for controlling the discharge speed. It is desired that the resistance 13 consumes the energy of the rechargeable battery 1 as soon as possible. However, if it is too early, a state similar to a short circuit occurs. Since it is not preferable for the life, the discharge rate is controlled. Generally, the resistance of the discharge current setting resistor 13 is set so that a current having a discharge rate of one hour or a current having a value approximately twice as large as the current flows.

Next, the operation of the circuit of FIG. 1 will be described. The positive electrode and the negative electrode of the rechargeable battery 1 in the range of the full charge and discharge stop voltages are mounted so as to correspond to the positive terminal 3 and the negative terminal 2 of the discharging device, respectively.

When the push button 11 is pressed, the leaf spring 8 whose one end is fixed at the fixing point A bends, and the movable contact 9 integrated with the leaf spring 8 is fixed at the tip of the opposite surface of the push button 11 to the fixed contact 10a. And contacts the fixed contact 10b to be turned on. Then rechargeable battery 1
The current flows through the fixed contact 10a, the movable contact 9 and the fixed contact 10b, and flows through the holding limit voltage setting resistor 12 to the coil 5 of the relay 4. When a current flows through the coil 5, a magnetic field is generated at the magnetic pole 6, and the iron piece 7 is attracted. Therefore, even if the pressing of the push button 11 is interrupted, the iron piece 7 continues to be sucked, the leaf spring 8 integrated with the iron piece 7 also keeps the bent posture, and the movable contact 9 at the tip is fixed contact 10a and fixed contact 10a. 10b is kept in contact with the self-hold.

At this time, a discharge current flows from the connection point 14 to the discharge current setting resistor 13 at the same time. The energy of the rechargeable battery 1 is released by the current that continues to flow through the discharge current setting resistor 13, and the terminal voltage between the terminals 2 and 3 decreases.

When the terminal voltage of the rechargeable battery 1 drops to a preset discharge end voltage, the magnetic force of the magnetic pole 6 of the relay 4 decreases, and the attractive force of the iron piece 7 becomes weaker than the return force due to the elasticity of the leaf spring 8. And the leaf spring 8 returns to the original position. The movable contact 9 is separated from the fixed contact 10a and the fixed contact 10b by this return operation, the load of the discharge battery 1 is all disconnected, and the discharge current stops.

As described above, according to the embodiment of the present invention, the structure of the electric circuit is simple, the number of components is small, the load can be reliably separated, and a large current can be supplied even at a low voltage. is there.

[Brief description of the drawings]

FIG. 1 is an electric circuit diagram of one embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Rechargeable battery 2 Minus terminal 3 Plus terminal 4 Relay 5 Coil 6 Magnetic pole 7 Iron piece 8 Leaf spring 9 Movable contact 10a, 10b
Fixed contact 11 Push button 12 Holding limit voltage setting resistor 13 Discharge current setting resistor 14 Connection point

──────────────────────────────────────────────────続 き Continued on front page (51) Int.Cl. ⁶ Identification code FI H02J 7/10 H02J 7/10 B

Claims (6)

[Claims] The present invention is characterized in that not only the holding limit voltage inherent to the relay but also an arbitrary voltage is detected by using a holding limit voltage of the relay for voltage detection and connecting a resistor in series to the relay. Electric circuit for voltage detection. 2. The discharge control of a rechargeable battery is performed by detecting a discharge voltage of the rechargeable battery.
The electric circuit for voltage detection according to the above. 3. A relay is connected between the positive terminal and the negative terminal of the rechargeable battery, and a holding limit current setting resistor is arranged in series with the relay wire. An electric circuit for detecting a voltage, wherein a discharge current setting resistor is connected in parallel to the electric circuit. 4. The voltage detecting electric circuit according to claim 1, wherein the holding limit current setting resistor and the discharge current setting resistor are adjustable semi-fixed resistors. 5. The voltage detecting device according to claim 1, wherein a button for manual discharging is added to the relay when a sufficiently charged battery is installed in the electric circuit for voltage detection according to claim 1. Electrical circuit for detection. 6. A battery is charged after the battery is once discharged to a discharge stop voltage, and the discharge circuit is held while the battery is being discharged to a predetermined voltage, and the discharge circuit is automatically cut off when the voltage drops to a predetermined voltage. An electric circuit for detecting a voltage.