JPS6024435A - Specific gravity sensor for lead battery - Google Patents

Abstract

PURPOSE:To obtain a specific gravity sensor, which has less self-discharge and displays stable potential difference even under shocks and vibration for a long time, by coating a lead electrode and a lead dioxide electrode by a porous tube having acid-resistance and oxidation-resistance properties such as glass fiber. CONSTITUTION:A main body 1 of a sensor comprises a synthetic resin and attached to a battery by a threaded part 2. A conating tube 3 of about 6mm.<phi> made of braided glass fiber coats a positive active material (PbO2) 6, whose raw material is lead powder, and a negative active material (Pb) 4, whose raw material is also lead powder, so as to prevent their falling and to prevent the direct contact of bubbles and fine particles to the positive and a negative active materials from the outside. Current collecting bodies 5 are formed by lead wires. The tube 3, in which the materials 4 and 6 are sealed, is closed by a bottom lid 7. Therefore the amount of self-discharge is few, the sensor is stable against shocks and vibrations, and the specific gravity of electrolyte can be accurately displayed for a long time.

Description

[Detailed Description of the Invention] The present invention is an electrode-type lead battery specific gravity sensor (hereinafter simply referred to as a specific gravity sensor) that measures the specific gravity of an electrolyte in a lead battery using a lead electrode (n electrode) and a lead dioxide electrode (Pb02 electrode). This is related to the improvement of.

Conventionally, electrode-type specific gravity sensors for lead batteries have used a /j\ piece of a paste-type electrode plate or a small piece of metal lead for the lead electrode (hereinafter referred to as the negative electrode), and a lead dioxide electrode (hereinafter referred to as the positive electrode). Combinations of negative and positive electrodes have been used, such as platinum wire electrodeposited with lead dioxide or small pieces of paste-type electrode plates.

However, when these electrodes are attached to a battery and used, the potential difference quickly decreases, and the electrodes have the disadvantage that they no longer provide an accurate indication of the specific gravity of sulfuric acid. The cause of this deterioration is as follows. In other words, the positive electrode is used for automobiles and electric vehicles.
When applied to a lead-acid battery for a 7-car vehicle, the active material, lead dioxide, gradually drops due to acceleration, shock, or vibration, causing a loss of capacity, and at the same time, the potential changes. On the other hand, at the negative electrode, lead dioxide fine particles carried by the convection of oxygen gas and electrolyte generated from the battery during charging directly contact the electrode surface and accelerate self-discharge, resulting in the same phenomenon as in the case of the positive electrode. Become.

The present invention solves the above-mentioned drawbacks, and provides a specific gravity sensor that has little self-discharge and exhibits a stable potential difference over a long period of time even against shocks and vibrations. The purpose is to cover the tube with a porous tube made of glass fiber or the like that is resistant to acid and oxidation.

Hereinafter, the present invention will be explained using the drawings. Figures 1 and 2 show an embodiment of the specific gravity sensor of the present invention, in which 1 is a sensor body made of synthetic resin, 2 is a threaded portion for attaching the sensor body 1 to a battery, and 3 is a braided glass fiber. The coating tube (approximately 6IIIlφ) is used to cover the positive and negative electrode active materials (to be described later) to prevent them from falling off, and to prevent air bubbles and fine particles from coming into direct contact with the negative and negative electrode active materials from the outside. In addition, in this example,
Although the covering tube 3 is made of braided glass fiber, any porous thin film that is acid- and oxidation-resistant may be used, such as a non-woven tube of glass fiber, a woven fabric of polyester fiber, or a non-woven fabric. A porous pipe made of sintered glass or alumina powder may also be used. In addition, 4 is a negative electrode active material (Pb) made from lead powder, and 5 is about 21
+11φ lead wire, 6 is positive electrode active material made from lead powder (P
bO2), 7 is the bottom lid of the covering tube 3 in which the positive and negative electrode active materials 4 and 6 are sealed.

Next, the embodiment of the present invention (product of the present invention) and a conventional specific gravity sensor of this type (conventional product) were used for an automotive lead battery (N, 540Z).
Lii when installed on the car and driving on the actual vehicle! Figure 3 shows the change over time in the acid ratio type indicated value. For comparison, the results of actual measurements using a hydrometer are also shown in Figure 3. As seen in the diagram, conventional products deteriorate after about a year, whereas
The product of the present invention followed the actually measured sulfuric acid specific gravity even after 21 months.

Furthermore, when the embodiment of the present invention (inventive product) and the conventional specific gravity sensor of this kind (conventional product) are attached to an overcharged battery whose sulfuric acid specific gravity is adjusted to 1,260/20°C, the sulfuric acid specific gravity indicated value is Figure 4 shows the change over time. As seen in the diagram, while the conventional product deteriorated after about 10 months, the product of the present invention shows normal indication even after 21 months, and is recognized to have a long lifespan.

As described above, the specific gravity sensor of the present invention has the advantages of having little self-discharge, being stable against shock and vibration, and being able to accurately display the electrolyte specific gravity for a long period of time. Advantages such as being able to accurately determine the discharge state of the battery and reducing maintenance can be achieved.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing an embodiment of the specific gravity sensor of the present invention;
Figure 2 is an enlarged sectional view taken along the line 8-A in Figure 1, and Figure 3 shows the specific gravity of sulfuric acid when the specific gravity sensor of the present invention and the conventional specific gravity sensor of this type are attached to an automotive lead battery. Figure 4 is a characteristic diagram showing changes in indicated values over time. Figure 4 is a characteristic diagram showing changes in indicated values over time when the specific gravity sensor of the present invention and a conventional specific gravity sensor of this kind are attached to an overcharged battery. be. 1...Sensor body, 3...Coated tube, 4...
Negative electrode active material, 6...Positive electrode active material 1st 'I 2nd N! 1

Claims (1)

[Claims] In a lead battery specific gravity sensor that measures the specific gravity of sulfuric acid using the potential difference between two electrodes, a lead electrode and a lead dioxide electrode, the lead electrode and the lead dioxide electrode are made of acid- and oxidation-resistant porous material such as glass fiber. A lead-acid battery ratio ■sensor characterized by being covered with a tube.