JPS59178929A - Charger of battery - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a battery charging device, and particularly to a device for charging a sealed battery to be charged. The present invention relates to a device that can be charged.

(b) Prior Art A sealed battery to be charged, such as a sealed nickel-cadmium battery, exhibits charging voltage characteristics as shown in FIG. 1 upon charging. As is clear from this characteristic diagram, the charging voltage and the peak voltage vary depending on the ambient temperature. However, in the conventionally widely used method of detecting a constant battery voltage and directly controlling the charging current, the amount of charging varies greatly depending on the ambient temperature.

In view of this, a method for detecting the peak point of charging voltage characteristics has been proposed (U.S. Patent No. 6,9-8.021 and Japanese Unexamined Patent Publication No. 58738/1983). This is accomplished by providing a voltage detection circuit that includes a resistor whose voltage across both ends changes according to the charging voltage of the battery, and a series circuit of a capacitor and a diode between both ends of the resistor to detect the voltage across the J diode. , a path has been established. That is, since the capacitor charging current flows through the series circuit until the battery voltage reaches its peak, the voltage across the diode is a forward voltage. After the battery voltage peaks, the voltage across the resistor gradually decreases, and due to the capacitor voltage,
A reverse bias voltage state is applied to the diode, and the detection circuit detects this state as I~
There is also a device that controls battery charging.

In this way, since the existing method detects the peak point and controls the temperature, it is possible to properly control battery charging regardless of changes in ambient temperature. .

However, does a battery that has been left for a long time until it is discharged (hereinafter referred to as an inviscid battery) recharge? When charging starts, the battery exhibits better characteristics than a normal battery at the beginning of charging. This example is shown in FIG. 1 by a two-dot chain line in the initial part of the characteristic at an ambient temperature of 20°C. When such an abnormal characteristic exists, the previously proposed system has the disadvantage that it detects the peak point 1X) of this abnormal characteristic and immediately controls battery charging.

←゛) Purpose of the Invention It is an object of the present invention to provide a device that can properly charge an inactive battery in the same way as a normal battery.

B)) Structure of the Invention In order to achieve the above object, an apparatus according to the present invention includes a detection circuit for detecting the charging voltage of a battery to be charged charged from a charging power supply circuit, and a voltage corresponding to the battery voltage in the detection circuit. A time constant circuit including a capacitor and a resistor provided at both ends of the resistor to be detected; a sensing circuit that senses when the voltage across the resistor in the time constant circuit is reversed; and charging of the battery by the output of the sensing circuit. The control circuit is configured to include a control circuit for controlling the ton.

←E) Example Hereinafter, an example of the present invention will be explained based on FIG. 2. 2 in this drawing, (1) is a charging power supply circuit, and a step-down transformer (Tl,
It is composed of a full-wave rectifier diode (DI) (D2) and a smoothing capacitor (C1) provided at both ends of the secondary coil of the transformer. A relay switch (R5) for charging control is inserted into the charging path (Ll) (R2) which is the output path of this charging power supply circuit (1), and the battery to be charged CB+ is connected via the relay switch. Ru.

A detection circuit (2) is provided between both ends of the battery to detect the charging voltage of the battery. The detection circuit consists of a series circuit of a resistor (R1) and first and second constant voltage elements (Zl) (Z2), both ends of which a voltage corresponding to the battery voltage appears. (
C2) is a ripple removal capacitor.

A time constant circuit (3) including a capacitor (C5) and a resistor (R2) is provided at both ends of the resistor (1L+), and a discharge resistor (R5) and a first switch are provided at both ends of the capacitor (C5). A series circuit of (Sl) is provided.

A sensing circuit that senses the positive/negative inversion of the voltage across +4J (ri low resistance R2) is configured with an operational amplifier (0).

+51 is a control circuit for controlling battery charging, and includes a first transistor (
Ql) and the relay coil (RY) that controls the opening and closing of the relay switch (R5) are connected to the charging path (Ll) (R2
) and a sixth constant voltage element (Z
5) and a resistor (R4), and a charging path (Ll
) (R2) becomes larger than the constant voltage of the sixth constant voltage element (Z3), the second transistor (C2) becomes conductive at the voltage of the resistor (R4) and isolates the first transistor (Ql). ) is provided. A second switch (Sl) is provided between the base and emitter of the second transistor to shut off the transistor. The second switch operates in conjunction with the first switch (Sl) and constitutes a starting switch.In the above configuration, the first and second switches (Sl) serving as starting switches are pressed and closed to open the capacitor (C5). ) is discharged and at the same time the second transistor (C2) is cut off. In this state, the battery FB+
At a voltage of , the voltage across the resistor (R2) becomes a positive voltage,
The operational amplifier (0) becomes a high output. Therefore, the first transistor (Ql) becomes conductive and the relay coil (RY) is excited, which closes the relay switch CR8) and causes the current a (
Charging of Bl is started. In this state, when the first and second switches (Sl) are released and opened, charging of the battery continues.

If the battery j131 is a normal battery, its charging voltage characteristics will be as shown in (I) in FIG. As shown in this figure, the battery voltage gradually increases until reaching the peak point (C4), and a voltage corresponding to this battery voltage appears across the resistor (R1) of the detection circuit 12). This voltage causes a current to flow through the time constant circuit (3), so at time (1+)1, the voltage (Vtl) across the resistor (R2) decreases due to the time constant of the circuit. This voltage characteristic is defined as tm Indicated by The voltage reduction characteristic is a so-called differential characteristic, and after time (tl), the battery voltage characteristic (11) gradually increases, but the voltage across the resistor (R2) remains approximately constant.At time (C2), the battery voltage As the voltage begins to rise rapidly, the resistance voltage (V After the peak point (C4), the battery voltage itself starts to decrease, but the resistance voltage (VR) does not immediately become a negative voltage at that point (C4), but after the time constant of the time constant circuit +37 (C5). ) becomes a negative voltage.The sensing circuit 14) senses this inversion to negative voltage, its output becomes low, and the first transistor (Ql) is cut off. For this reason, the relay coil (
RY) is in a non-excited state, the relay coil chain (R8) is opened, and the charging of the electric a+Bl is completed. Relay coil loop (
RS), the voltage between the charging path (Ll) and (R2) rises to 1, the sixth constant voltage element (Z5) becomes conductive, and the voltage of the resistor (R4) causes the second transistor (Q2
) holds the first transistor (Ql) in the cut-off state.

Next, we will explain the case where the battery (Bl) is an inactive battery.The battery voltage itself due to charging e in this case is shown in Figure 4 (
Indicated by I[). In this characteristic (■), the voltage is high at the beginning of charging, gradually decreases, and thereafter shows the same characteristic as the characteristic of a normal battery <11. The period of this abnormal characteristic region at the beginning of charging is extremely short, and the resistance (
After the time (tl) when the influence of this abnormal characteristic disappears, the voltage characteristic aV) of R2) becomes a characteristic that is approximately the same as the resistance voltage characteristic [+] and - in the case of a normal battery.

That is, the time constant of the specific number of times (1M+3) is determined to be slightly larger than the period during which the influence of the abnormal characteristics disappears. Therefore, charging of the battery ends after the peak of the battery voltage characteristic 1111), just like a normal battery, without being affected by the abnormal characteristic.

In the third embodiment, the detection circuit (2) is composed of a resistor (R1) and first and second constant voltage elements (Zl) (Z2), but it is also possible to use a resistive voltage divider circuit consisting of two or more resistors. You may also use one option.

b) Effects of the Invention As described above, the charging device according to the present invention includes: a detection circuit that detects the charging voltage of the battery to be charged charged from the charging power supply circuit; and a voltage corresponding to the battery voltage within the detection circuit. a time constant circuit including a capacitor and a resistor provided at both ends of the resistor, and a l1ii of the resistor in the time constant circuit;
] It is equipped with a sensing circuit that senses the positive/negative inversion of the terminal voltage, and a control circuit that controls charging of the battery based on the output of the sensing circuit; Due to the presence of the inert battery, there is a delay function for the differential pressure V at the beginning of charging of the inert battery, and the inert battery can also be charged normally (like a battery).

[Brief explanation of drawings]

Figure 1 is a battery voltage characteristic diagram for different ambient temperatures, Figure 2
The figure is an electric circuit diagram showing a failed embodiment of the present invention, Figure 6 is a characteristic diagram of the charging voltage of a normal battery and the voltage across the resistor, and Figure 4 is the characteristic of the charging voltage of an inactive battery and the voltage across the resistor. It is a diagram. (1)...Charging power supply circuit, (B)...Battery to be charged,
(2)...Detection circuit, (R1)...Resistor, (C5)
...Condenser length, (R2)...Resistance, +31...
Time constant circuit, (4)...sensing circuit, 5)...control circuit.

Claims (1)

[Claims] (1) A detection circuit that detects the charging voltage of the battery to be charged charged from the charging power supply circuit, and a capacitor and a resistor installed at both ends of the resistor that detects the voltage corresponding to the voltage in the detection circuit. a sensing circuit that senses that the voltage across the resistor in the time constant circuit is inverted between positive and negative; and a control circuit that controls charging of the '4 battery based on the output of the sensing circuit. A battery charging device.