JPH069146B2 - Specific gravity sensor for lead batteries - Google Patents

Description

TECHNICAL FIELD The present invention relates to a specific gravity sensor for measuring the specific gravity of an electrolytic solution of a lead battery.

[Prior Art] The charge / discharge state of a lead battery can be determined most accurately by measuring the specific gravity.

This is because the electrolyte specific gravity changes the battery capacity (chemical reaction amount).
This is because the specific gravity depends only on, and the specific gravity also changes in proportion to the amount of discharged electricity. Therefore, by measuring the specific gravity of the electrolytic solution, it is possible to clearly know how much the battery has been discharged or how much more the battery can be discharged. As a specific gravity measurement method, it was general to use a suction type float pycnometer, but recently, with the intention of keeping the storage battery free, the battery and charger are automatically controlled so that the charge / discharge amount of the battery can be automatically controlled. Specific gravity sensors have been used to couple the.

Conventionally, a PbO ₂ electrode and Pb have been used as a specific gravity sensor of this type.
What is called an electrode-type specific gravity sensor is used which uses an electrode pair of electrodes and utilizes the characteristic that the potential difference indicated by this electrode pair and the value of the specific gravity of sulfuric acid, which is the electrolyte, have a substantially linear relationship.

[Problems to be solved by the invention]

However, in the above-mentioned electrode-type specific gravity sensor, the electrodes self-discharge during use to generate lead sulfate (PbSO ₄ ), and the normal potential is not exhibited in a short period of time. In order to avoid such a state, a method of periodically charging and activating the electrode of the specific gravity sensor has been proposed, but it is more accurate due to the deviation from the equilibrium voltage due to the influence of polarization during the open state during charging or after charging. It took a long time to detect the specific gravity.

In order to eliminate this polarization, a method has been proposed in which both electrodes of the specific gravity sensor are partially discharged at the same time after charging to accelerate stabilization of the potential difference.

However, according to this method, the specific gravity sensors PbO ₂ and Pb
Of the two electrodes, the Pb electrode is deteriorated earlier. This is because the Pb electrode has a larger self-discharge acceleration than the PbO ₂ electrode due to self-discharge acceleration factors such as Sb contamination.

Therefore, as a result of further detailed examination of the reason why it takes time to attenuate the polarization in the open circuit state after charging the specific gravity sensor for the PbO ₂ electrode and the Pb electrode, it was found that there is a cause for the PbO ₂ electrode. Based on these results, the present invention proposes a method of using a new specific gravity sensor, which will be described in detail below.

[Means for solving problems]

It is an object of the present invention to solve the above-mentioned drawbacks of the conventional electrode-type specific gravity sensor and to provide a specific gravity sensor capable of accurately measuring the electrolytic solution specific gravity of a lead battery over a long period of time. The point is that in charging / discharging the specific gravity sensor, the Pb electrode receives only the charging current, and the discharging is performed by the other electrode.
On the other hand, the PbO ₂ electrode receives only a certain portion of the charging current, the other portion receives the portion exceeding the charging current, and the discharging is performed by the PbO ₂ electrode for the entire current.

〔Example〕

Embodiments of the specific gravity sensor for a lead battery of the present invention will be described below with reference to the drawings. FIG. 1 shows a specific gravity sensor mounted on a battery and an electric circuit using the specific gravity sensor of the present invention.

1 is a battery case, 2 is the same lid, 3 is the same electrolyte solution, 4 is the same negative electrode plate, 5 is the same negative electrode terminal, 6 is the same negative electrode terminal, 6 is the same negative electrode terminal, 8 is the same positive electrode terminal, 8 is a specific gravity sensor support, and the battery It can be screwed into the liquid port of the lid 2. 9 is a Pb electrode of the specific gravity sensor, 10
Is a lead wire of the Pb electrode 9, 11 is PbO ₂ of the specific gravity sensor
Electrodes, 12 are lead wires of the PbO ₂ electrode 11, 13 is a diode inserted so that current flows only in the direction in which the Pb electrode 9 is charged, and 14 makes current flow in the direction in which the negative electrode plate 4 of the battery is discharged. , A diode 15 inserted so that a current flows in a direction in which the PbO ₂ electrode 11 of the specific gravity sensor discharges, and a field effect transistor (FET) 16 inserted a potentiometer between the gate and the source, It is adjusted so that only a constant current flows,
As a result, only a certain part of the charging current is PbO.
It flows into the _two electrodes 11. Reference numeral 17 is a diode inserted in the positive electrode plate of the battery so that a charging current flows, and 18 is a charging / discharging device, which can set a constant charging / discharging current and a constant charging / discharging time. Reference numeral 19 denotes a potential difference measuring device when the specific gravity sensor is opened. Charge / discharge device 18
The operation of is usually one cycle of charging for one hour, discharging for one minute immediately after that, and about 23:00 when left open circuit.

In this embodiment of the present invention, when the charging / discharging device 18 is in the charging state, the current flow is through the field effect transistor 16 connected to the lead wire 12 of the PbO ₂ electrode 11 so that the required amount of current flows. The extra current flows through the diode 17 and into the positive electrode plate of the battery. The total charging current flowing into the electrode liquid 3 is Pb of the specific gravity sensor.
Charge / discharge device 18 enters electrode 9 and goes through diode 183.
Return to. On the other hand, when the charging / discharging device 18 is in a discharging state, the current output from the charging / discharging device 18 passes through the diode 14 to discharge the negative electrode plate 4 of the battery. At this time, since the Pb electrode 9 of the specific gravity sensor is prevented from being discharged by the diode 13, it is not discharged. The current that has entered the electrolytic solution 3 from the negative electrode plate 4 enters the PbO ₂ electrode 11 of the specific gravity sensor and returns to the charging / discharging device 18 via the diode 15.

Summarizing the characteristics of the embodiments of the present invention, the magnitude of the charging current of the specific gravity sensor can be set arbitrarily, and the current required for self-discharge recovery of the Pb electrode 9 can be selected. On the other hand, the PbO ₂ electrode 11 is always charged only with the specified current, and the extra current is used for charging the positive electrode plate of the battery. Also, during discharge, the Pb electrode 9 is not discharged at all,
The O ₂ electrode 11 discharges only the current designated by the charging / discharging device 18, and the potential can be accelerated and stabilized.

FIG. 2 is a characteristic diagram in which the specific gravity sensor of the present invention and the conventional specific gravity sensor are mounted on the same battery, and the changes over time of the sensor voltage corresponding to the specific gravity of the electrolyte solution (specific gravity 1.200 in this test) are compared. is there. As can be seen from the figure, the life of the conventional specific gravity sensor is 2 to 3 years, whereas the product of the present invention operates normally even after 4 years or more. In the above embodiment, in order to achieve the object of the present invention, the charge / discharge control of the specific gravity sensor electrode is performed by using the diode. However, when the charge / discharge control device 18 switches the charge / discharge, such as for switching, charging certain portion of the charging current to the PbO ₂ electrode, the Pb electrode are accepted all of the charging current, discharging all of the discharge current is performed only in the PbO ₂ electrode, P
Any means may be used as long as it is not applied to the b electrode. Further, in the above embodiment, an example in which the battery negative electrode is used as the opposite electrode for discharging the PbO ₂ electrode is shown, but a dummy electrode may be separately provided instead of the battery negative electrode.

〔The invention's effect〕

As described above, the specific gravity sensor of the present invention is used for PbO ₂ , Pb
Since the potential difference between the b electrodes stabilizes early and at the same time, the self-discharge of the Pb electrode is compensated by the required charge amount, the measurement can be performed with high accuracy, and the long life is maintained, which contributes to maintenance-free lead batteries. It's big.

[Brief description of drawings]

FIG. 1 is a block diagram showing a state in which one embodiment of the specific gravity sensor for lead batteries of the present invention is mounted on a battery, and FIG. 2 shows the specific gravity of electrolytes for the lead battery specific gravity sensor of the present invention and a conventional lead battery specific gravity sensor. It is a characteristic view which compares and shows the time-dependent change of the corresponding sensor voltage. 5 ... Negative electrode terminal of battery, 8 ... Specific gravity sensor support pair, 9 ... Pb electrode, 11 ... PbO ₂ electrode, 16 ... Field effect transistor, 18 ... Charge / discharge device, 19 ... Potentiometer ，

Claims (1)

[Claims] 1. A lead battery for measuring the specific gravity of an electrolytic solution by utilizing a potential difference when a pair of electrodes composed of a PbO ₂ electrode and a Pb electrode are charged and then partially discharged to stabilize the potentials of both electrodes. In the specific gravity sensor, a certain portion of the charge is the PbO.
Performed between the _second electrode and the Pb electrode, the portion exceeding the predetermined portion of the charge is performed between the battery Seikyokuto, the Pb electrode and the electrodes other than the PbO ₂ electrode, the discharge, the PbO ₂ A specific gravity sensor for a lead battery, which is carried out between an electrode and an electrode other than the Pb electrode, such as a battery negative electrode.