JP2876235B2 - Method for measuring internal impedance of lead-acid battery - Google Patents

Description

The present invention relates to a method for measuring the internal impedance of a lead storage battery.

2. Description of the Related Art Conventionally, the life of a sealed lead-acid battery (decrease in electrolyte and deterioration of an anode grid) has been determined from changes in the internal impedance of the lead-acid battery. In a conventional method of measuring the internal impedance, a measurement current including an AC current component is applied between an anode and a cathode of a lead storage battery to be measured, and the internal impedance is calculated from an AC voltage component between predetermined measurement electrodes. Is measured. When measuring the decrease in the electrolyte, set the frequency of the alternating current component of the measurement current to a high frequency (for example, 100 Hz or more, usually 1 kHz). When measuring the deterioration of the anode grid, the alternating current component of the measurement current is measured. Is set to a low frequency (for example, 100 Hz or less). The applicant has also applied for an apparatus for detecting the deterioration state of a lead storage battery using this conventional method (Japanese Patent Application No. 63-79586).

[Problems to be Solved by the Invention] In the conventional method, when measuring the internal impedance of a lead-acid battery of a relatively high voltage in which a plurality of cells are connected in series at a low frequency, the measured current is measured according to the voltage of the battery. It is necessary to increase the power supply voltage of the measuring current supply device to be supplied.
This is because it is difficult to supply a measured current including a low-frequency AC current component to a lead storage battery to be measured through a transformer or a coupling capacitor. It has to be DC coupled,
For that reason, it is necessary to make the power supply voltage of the measurement current supply device higher than the battery voltage. When the power supply voltage of the measuring current flow device increases, power consumption inevitably increases, and the amount of heat generated by the control elements such as switching devices used in the measuring current flow device increases. Vessel is required. As a result, there is a problem that it is difficult to reduce the size of the impedance measuring device by the conventional method.

The present invention provides a method for measuring a internal impedance from an AC voltage component between predetermined measurement electrodes by applying a measurement current including an AC current component between an anode and a cathode of a lead storage battery to be measured. It is an object of the present invention to provide a method capable of measuring the internal impedance of a measured lead-acid battery without increasing the power supply voltage even when the measurement is performed by applying a measurement current including an AC current component.

[Means for Solving the Problems] In the method of the present invention, a measurement current is supplied to a measured lead storage battery in a state where a secondary battery is connected in series in a direction to offset the voltage of the measured lead storage battery. Then, a lead storage battery having the same characteristics as the lead storage battery to be measured is used as the secondary batteries connected in series. Further, in the present invention, the lead storage battery connected as a secondary battery is floatingly charged.

[Operation] If a secondary battery is connected in series to the lead storage battery to be measured in such a direction as to cancel the voltage of the lead storage battery, the battery voltage of the lead storage battery to be measured can be canceled out. Power supply voltage can be reduced. As a result, power consumption and calorific value of the measurement current supply device can be reduced. Therefore, according to the method of the present invention, it is possible to use a small-sized and small-sized current-flowing device. If the secondary battery connected in series is a lead storage battery having the same characteristics as the lead storage battery to be measured, the voltage of the lead storage battery to be measured can be equivalently canceled, and the power supply voltage of the measurement current supply device can be minimized. it can. Furthermore, if a lead storage battery connected as a secondary battery is float-charged, this lead storage battery can always be kept in a fully charged state having a low internal impedance, and the voltage of the lead storage battery to be measured can be canceled out equivalently.
A measurement current containing an AC current component also flows through a lead-acid battery connected as a secondary battery.However, in this lead-acid battery, only charging / discharging current due to the AC current flows and there is almost no discharge. A small capacity is acceptable.

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

The drawing shows an example of a device on the measurement current conducting side used for carrying out the method of the present invention, and the configuration of the measuring device for measuring the internal impedance is omitted because it is known. In the figure, 1 is an AC signal oscillator,
2 is an amplifier circuit, 3 and 4 are energization control transistors,
Reference numeral 5 denotes a power supply, 6 denotes a lead storage battery to be measured (in the embodiment, a sealed lead storage battery), 7 denotes a current detection resistor, 8 denotes a secondary battery, and 9 denotes a floating charger. The AC signal oscillator 1 is configured to generate an AC signal having a desired frequency, and an output voltage V of the AC signal oscillator 1 is input to a + input terminal of the amplifier circuit 2. The voltage at both ends of the current detection resistor 7 is input to the − input terminal of the amplifier circuit 2, and the amplifier circuit 2 outputs V / V based on the resistance value R of the current detection resistor 7 and the output voltage V of the AC signal oscillator 1. It is configured to supply a base current to the control transistors 3 and 4 so that an AC current having a magnitude of R is supplied to the lead storage battery 6 to be measured. Although only the control transistors 3 and 4 are schematically shown in the figure for the sake of simplicity, in practice, both the positive and negative polarity signals output from the amplifier circuit 3 and the voltage from the power supply 5 are shown. A protection circuit for protecting control transistors 3 and 4 is provided.

The power supply 5 includes a first output terminal 5a that outputs a forward voltage to the control transistor 3 including an NPN transistor;
A second output terminal 5b for outputting a forward voltage to the control transistor 4 comprising a PNP transistor. When a signal having a positive polarity is output from the amplifier circuit 2, the transistor 3 is turned on, and a power supply of one polarity is supplied to the lead storage battery 6 from the power supply 5 through the turned on transistor 3. When a signal having a negative polarity is output from the amplifier circuit 2, the transistor 3 is turned off, the transistor 4 is turned on, and the current of the other polarity is supplied to the lead storage battery 6 to be measured through the transistor 4 turned on from the power supply 5 (in FIG. (A current flowing from the ground terminal to the output terminal 5b). The transistors 3 and 4 are repeatedly turned on and off in synchronization with the frequency of the output signal of the AC oscillator 1, and an AC current is supplied to the lead storage battery 6 to be measured.

The secondary battery 8 is connected in series to the measured lead-acid battery 6 in a direction to cancel the voltage of the measured lead-acid battery 6, that is, in a direction of the opposite polarity when viewed from between the outputs of the transistors 3 and 4 and the resistor 7. Have been. In this embodiment, in order to equivalently cancel the voltage of the lead storage battery 6 to be measured by the voltage of the secondary battery 8, the secondary battery 8 has characteristics (voltage, capacity, etc.) different from those of the lead storage battery to be measured.
Use the same lead-acid battery, and this lead-acid battery is
Floating charging. If the secondary battery 8 is connected in the opposite polarity to the lead storage battery 6 to be measured in this manner, the secondary battery 8
In this case, the voltage of the power supply 5 can be made much lower than in the case where the power supply 5 is not inserted, and an alternating current can be supplied. Therefore, the power consumption of the entire device can be reduced, the withstand voltage of the transistors 3 and 4 can be reduced, and the amount of heat generated by the transistors 3 and 4 can be reduced.

The internal impedance of the lead-acid battery 6 to be measured is generally measured by using the anode and the negative electrode of the lead-acid battery 6 to be measured and detecting an AC voltage component between both electrodes. When a dedicated measurement electrode is provided in such a manner that the electrode contacts the electrolyte but does not contact the anode and the cathode, the impedance between the anode and the measurement electrode may be measured.

As the lead storage battery used as the secondary battery 8, it is preferable to use a lead storage battery having the same characteristics as the lead storage battery to be measured. However, the effects of the present invention can be obtained by using a lead storage battery having different characteristics. In order to confirm this, a 12 V, 50 Ah cathode suction type lead storage battery, that is, a sealed lead storage battery was used as the lead storage battery 6 to be measured, and a 12 V, 1.2 Ah sealed lead storage battery was used as the secondary battery 8. amplitude tested by energizing the measured current of 1A ^PP at 0.1Hz in lead-acid battery 6. At this time, the output terminals 5a and 5b of the power supply 5
It was confirmed that the above measurement current could be supplied when the output voltage from the device was ± 5 V or more. For comparison, the secondary battery 8
When the experiment was performed under the same conditions with removing the above, it was impossible to supply the same measurement current as described above unless the output voltage from the power supply 5 was at least ± 15 V or more. Therefore, in this example, by using the present invention, the output voltage of the power supply 5 can be reduced to 1/3, and as a result, the power consumption can be reduced to about 1/3.
It was confirmed that it could be done.

In the above embodiment, in order to obtain the best result,
However, when implementing the present invention, it is not always necessary to perform the floating charge, and the effect of the present invention can be obtained even if a battery having a low internal impedance is used as it is as a secondary battery.

Further, the method of the present invention can of course be carried out using an energizing device having a configuration other than the measuring current energizing device shown in the drawings.

It is not necessary to remove the secondary battery 8 from the energizing circuit even when a high-frequency alternating current is applied by using the apparatus of the present embodiment.

[Effects of the Invention] According to the present invention, a secondary battery is connected in series to a measured lead storage battery in a direction to offset the voltage of the measured lead storage battery, and a measurement current is applied. The battery voltage can be canceled, and as a result, the power supply voltage of the measurement current supply device can be reduced, and the power consumption and heat generation of the measurement current supply device can be reduced. Therefore, according to the method of the present invention, it is possible to use a small-sized and small-sized current-flowing device.

In particular, if the secondary battery connected in series is a lead storage battery having the same characteristics as the lead storage battery to be measured as in the present invention, the voltage of the lead storage battery to be measured can be equivalently canceled, and the power supply voltage of the measurement current supply device can be reduced There are advantages that can be minimized. If a lead storage battery connected as a secondary battery is float-charged, there is an advantage that the lead storage battery can always be kept in a fully charged state with a low internal impedance and the voltage of the lead storage battery to be measured can be equivalently canceled.

[Brief description of the drawings]

The drawing is a circuit diagram showing a schematic configuration of an example of a device on the measurement current supply side used for carrying out the method of the present invention. DESCRIPTION OF SYMBOLS 1 ... AC signal oscillator, 2 ... Amplification circuit, 3,4 ... Transmission control transistor, 5 ... Power supply, 6 ... Lead storage battery to be measured, 7 ... Resistance for current detection, 8 ... Secondary battery , 9 ... Floating charger.

Continuation of the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G01R 31/36 H01M 10/42-10/48 301 G01R 27/00-27/31 H02J 7/00-7/12 H02J 7/34-7/36

Claims (1)

(57) [Claims] 1. A method for applying a measurement current containing an AC current component between an anode and a cathode of a lead storage battery to be measured from a measurement current supply device and measuring an internal impedance from an AC voltage component between predetermined measurement electrodes. In the above-mentioned lead-acid battery to be measured, the measurement current is passed in a state where a secondary battery is connected in series in a direction to offset the voltage of the lead-acid battery to be measured, and the same as the lead-acid battery to be measured as the secondary battery A method for measuring the internal impedance of a lead-acid battery, wherein the lead-acid battery used as the secondary battery is float-charged using a lead-acid battery having characteristics.