JPS5925030Y2 - Battery capacity detection device - Google Patents

Description

[Detailed explanation of the idea] The present invention relates to a battery capacity detection device.

This type of conventional device connects a battery to a capacitance detector that does not have a charging power source and detects the terminal voltage of the battery.

However, in a battery such as a nickel-cadmium battery, as time passes after charging is completed, the terminal voltage of the battery gradually decreases even though it has a charging capacity, and in some cases, the terminal voltage decreases to the same level as that of an uncharged battery.

Therefore, detection of battery terminal voltage by a capacitance detector without a charging power source results in erroneous detection.

The present invention has been devised in view of these points, and one embodiment of the present invention will be described below with reference to the drawings.

1 is a step-down transformer whose primary coil 2 is connected to commercial power supply terminals 3, 3, and whose secondary coil 4 is connected to the connecting terminal 8, of the first battery 7 via an automatic reset switch 5 and a rectifier diode 6 Connected to 8.

Connection terminals 11 and 11 of a second battery 10 are connected between both ends of these terminals 8 and 8 via a current limiting resistor 9, and the other battery 7
or 10 selectively corresponds to the corresponding connection terminal 8.8 or 11.
11.

Further, a resistive voltage divider circuit 14 consisting of resistors 12 and 13 is connected between both ends of the connecting terminal 8°8.

15 is when the rectifier diode 6 is conducting half-wave, that is, when the battery 7 or 1
The emitter base is connected to 2 so that conduction occurs during half-wave charging
A transistor is connected to both ends of the coil 4 via a base resistor 16, and its collector is connected via a resistor 17 to a voltage dividing point 18 of a resistive voltage dividing circuit 14.

Next, the tertiary coil 19 of the step-down transformer 1 is connected to the full-wave rectifier circuit 2.
0, and a smoothing capacitor 21 is connected to its DC output end.

A diode 22 that generates a reference voltage is connected between both ends of this smoothing capacitor, and a programmable unijunction
The anode/cathode of a transistor (hereinafter referred to as PUT) 23, a light emitting diode 24, and a current limiting resistor 25 are connected in series, and the gate of PUT 23 is connected to the transistor 15.
It is connected to the voltage dividing point 18 via the collector of , that is, the resistor 17 .

In the above configuration, when a battery, for example 7, charged with another charger is inserted between the connecting terminals 8 and 8, and the automatic reset switch 5 is temporarily closed for, for example, 2 seconds, the output of the secondary coil 4 is is a half wave of the indicated polarity (hereinafter referred to as positive half wave)
, the battery 7 is rapidly charged with a large current, and the transistor 15 is made conductive to increase the gate voltage of the PUT 23, thereby preventing the divided voltage of the resistor voltage divider circuit 14 from being expressed to the gate of the PUT.

On the other hand, during the negative half wave, no charging current flows to the battery 7 due to the diode 6, and the transistor 15 is reverse biased, so it is in a cutoff state.

Therefore, the battery voltage is detected as a divided voltage of the resistance voltage divider circuit 14, and this divided voltage is expressed at the gate of the PUT 23.

On the other hand, a reference voltage from a diode 22 is applied to the anode of the PUT 23.

Therefore, the difference voltage between the divided voltage and the reference voltage is output to PUT23.
is compared, and when the voltage difference is equal to or higher than a predetermined voltage, PUT becomes conductive and lights up the light emitting diode 24 every negative half wave.

Also, when the battery is charged to the specified state of charge,
The divided voltage increases and the base voltage between this divided voltage and the reference voltage becomes less than a predetermined voltage difference, the PUT 23 is in a cutoff state, and the light emitting diode 24 continues to turn off, indicating that the battery is in a predetermined charging state. indicate.

As described above, according to the configuration of the present invention, when detecting the battery capacity, the detected battery is recharged when the automatic reset switch is closed and the battery voltage is detected. Even in the case of a battery exhibiting a voltage, its terminal voltage can be quickly recovered by recharging, and accurate capacity detection can be performed.

In addition, the battery is charged with a half-wave rectified current, and during the half-wave charging of the battery, a transistor is used to block the expression of the divided voltage of the resistor voltage divider circuit connected in parallel to the battery, so that the non-charging half of the battery is The detection element can detect the predetermined base voltage of the divided voltage of the resistive voltage divider circuit and the reference voltage of the constant voltage element during the wave period, and compared to the case where the battery voltage is detected during the half wave period of charging the battery, There is no influence of contact resistance between the connection terminal and the battery voltage can be detected correctly.

[Brief explanation of drawings]

The drawing is an electrical circuit diagram showing an embodiment of the device according to the present invention. 7.10...Battery, 14...Resistor voltage divider circuit, 15...Transistor, 22...
・Constant voltage element, 24... Indicator light, 23...
...Detection element.

Claims (1)

[Scope of utility model registration request] A resistive voltage divider circuit that expresses the divided voltage of a battery charged by a half-wave rectified current, a transistor that prevents the expression of the divided voltage of the voltage divider circuit during half-wave charging of the battery, and a reference voltage that is generated. A battery capacity detection device comprising a constant voltage element and a detection element that detects a predetermined voltage difference between the divided voltage and a reference voltage during a half-wave of non-charging of the battery and lights up an indicator light.