JPS596451Y2 - Battery capacity detection device - Google Patents

Description

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

Since the terminal voltage of a dry battery varies depending on the amount of remaining electricity, that is, the capacity, the capacity can be detected by directly detecting the terminal voltage.

However, when a secondary battery such as a nickel-cadmium battery is not energized, it has approximately the same terminal voltage regardless of its capacity, so it is not possible to accurately detect the capacity by directly detecting the terminal voltage.

The present invention has been devised in view of the above points, and the secondary battery is energized to activate the battery, and the energization is the positive half wave of the AC power supply, and the battery is activated during the negative half wave, that is, when the battery is not energized. By detecting the voltage, it is intended to eliminate errors in the detected voltage due to contact resistance between the battery and its connection terminals.

An embodiment of the present invention will be described below with reference to the drawings.

In Figure 1, 1 is a power transformer whose primary coil 2 is connected to a commercial power source via a switch 3;
The secondary coil 4 has terminals 5 and 6 at both ends and an intermediate terminal 7, and between the terminals 5 and 7, a connection terminal 13 of two sets of test batteries 11 and 12 is connected via a current limiting resistor 8 and diodes 9 and 10. ,13,
14.14 is connected, and a resistor 15.1 is connected between 13.13.
A voltage dividing circuit 17 including a resistor 18 is connected between 14 and 14.

For example, a AAA battery 11 is selectively inserted into the terminal 13.13, and a AAA battery 12 is selectively inserted into the terminal 14.14, so that the same current flows through the two types of batteries. However, the detected voltage becomes high and is corrected by the resistor 18.

Further, a series circuit of a diode 19 and a capacitor 20 is connected between the terminals 5 and 7 of the secondary coil 4, and an indicator light 22 is connected to both ends of the capacitor via a silicon controlled rectifier (hereinafter referred to as SCR) 21. Connected.

Next, 23 is a detection circuit connected between terminals 6 and 7 of the secondary coil 4 via a diode 24, and the detection circuit consists of a first transistor 26 whose base is connected to an intermediate voltage dividing point 25 of a resistor 15.16. and a second transistor which operates inversely to the transistor.
The collector of the second transistor is connected to the gate of the SCR 21.

In the above configuration, the test battery 1 is connected to the connection terminal 13.13.
1 is inserted and connected, and switch 3 is closed for a few seconds, for example,
A large current of 1 A, for example, a positive half wave of the AC power supply, flows through the battery, activating the battery 11, and detecting the battery voltage in the voltage dividing circuit 17.

FIG. 2 is a voltage characteristic diagram of batteries with different capacities as a function of the current flow time, and the capacity is expressed in %.

Therefore, the detection circuit 23 detects the negative half wave of the AC voltage, that is, when the battery 1
Since the voltage dividing circuit 17 operates when the battery 11 is not energized, the battery voltage appears in the voltage dividing circuit 17 regardless of the contact potential difference between the connecting terminal 13 and the battery 11 due to the energizing current. If so, the corresponding voltage V appears at the voltage dividing point 25 and the first transistor 26 becomes conductive.

Therefore, the second transistor 27 is cut off and its collector voltage rises, so that the SCR 21 is turned on, and the smoothed voltage of the capacitor 20 makes the SCR conductive, causing the indicator lamp 22 to light up.

On the other hand, when the capacity of the test battery 11 is small, the voltage dividing circuit 17
Since the voltage at the voltage dividing point 25 is low, the first transistor 26 is cut off, the second transistor 27 is turned on, and the gate signal of the SCR 21 is small and does not turn on.

As described above, according to the present invention, a positive half-wave current of an AC voltage is applied to the battery to be tested to activate the battery and express a battery voltage according to the capacity, and at the negative half-wave of the AC voltage, i.e. When the battery voltage is detected when the battery under test is not energized and the battery under test has a predetermined capacity or more, the indicator light is turned on by the smoothed voltage of the capacitor, so that the energizing current at the connection terminal of the battery under test is The capacitance can be detected without being affected by the contact potential difference caused by the voltage, and since the indicator light is lit based on the smoothed voltage of the capacitor rather than the voltage of the battery being tested, unnecessary discharge of the battery can be reduced. This has a great effect.

[Brief explanation of the drawing]

FIG. 1 is an electric circuit diagram showing an embodiment of the present invention, and FIG. 2 is a voltage characteristic diagram of the current flowing through batteries of different capacities depending on the current flowing time. 1...Power transformer, 11, 12...
Test battery, 13, 13, 14.14... Connection terminal, 19... Diode, 20... Capacitor, 21... SCR, 22...・・・・・・
Indicator light, 23...Detection circuit.

Claims (1)

[Scope of utility model registration request] Connect the connecting terminal of the battery under test, which is energized in a positive half wave, to the secondary side of the power transformer in parallel with a series circuit of a diode and a capacitor, and provide an indicator light between both ends of the capacitor via a silicon-controlled rectifier. and between the connection terminals,
A detection circuit for the battery under test is energized by the negative half-wave of the secondary side of the transformer and is composed of a pair of transistors, one of which is connected to the base and the other collector, and the output of the circuit is used to control the rectifier. A battery capacity detection device that ignites and lights up an indicator light.