JPH03182064A - Specific gravity sensor for lead-acid battery - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a specific gravity sensor for lead-acid batteries, and more particularly to a specific gravity sensor for lead-acid batteries that can prevent deterioration of electrodes.

Prior art and its problems As conventional specific gravity sensors for lead-acid batteries that apply electrochemical reactions, those that utilize the following reaction formulas (1) to (2) are known.゛That is, Pb+H2So4 =Pbso4
+2HPbSO4+2H2＋＋＋＋＋＋＋＋＋＋■P
bO2+H2SO4+2H++2)3-:PbSO4+
2H2()=■. The above reaction formula ■ is a negative f using lead.
The above reaction formula (2) shows the reaction at the positive electrode using lead dioxide. Therefore, in the electrolytic solution, the reaction shown by the following reaction formula (2) occurs.

Pb + pbo2 + 2H2SO4→2PbSO4
+ 2H20... ■The electromotive force in the above reaction formula ■ is,
Since it changes depending on the concentration of the electrolytic solution, by measuring this electromotive force, the concentration of the electrolytic solution, that is, the specific gravity can be measured.

However, since the monopolar potential of lead in the reaction formula (2) is higher than the hydrogen evolution potential, and the monopolar potential of lead dioxide in the reaction formula (2) is lower than the oxygen evolution potential, when immersed in the electrolytic solution for a long time, the reaction formula There was a drawback that the reaction (2) progressed and lead and lead dioxide changed to lead sulfate, making it impossible to measure the electromotive force.

OBJECTS OF THE INVENTION The present invention solves the above-mentioned drawbacks, and aims to provide a specific gravity sensor for lead-acid batteries that can measure electromotive force even when immersed in an electrolytic solution for a long time.

Composition of the invention The specific gravity sensor for lead-acid batteries of the present invention is a single Ff1M.

It consists of a first electrode whose potential is lower than the hydrogen generation potential, and a second electrode whose monopolar potential is higher than the oxygen generation potential, and each of the above-mentioned 1!
The electrode is coated with a separation membrane that allows hydrogen ions and sulfate ions to pass through, but does not allow all ions to pass through.

EXAMPLES The following examples will be explained below. Figure 1 shows lead 11 of the present invention.
[It is a cross-sectional view of a specific gravity sensor for parts. In Figure 1,
Reference numeral 1 denotes a first electrode whose unipolar potential is lower than the hydrogen generation potential, and is preferably made of a metal such as antimony. 2 is a second electrode having a monopolar potential higher than the oxygen generation potential, and is preferably made of a sulfate that is sparingly soluble in the electrolytic solution, such as silver sulfate. Such a first electrode 1
and second electrode 2 are covered with a separation membrane 5 that allows hydrogen ions and sulfate ions to pass through but not metal ions, and is attached to the lid 4 of a lead-acid battery. In addition, a lead wire IA is connected to each of the electrodes.

19e, so that the 2mm is pulled out and the electromotive force can be measured.
do. The first of these specific gravity sensors for Ki storage batteries!
At the pole, the reaction shown by the following reaction formula (2) occurs.

2 Sb + 3H204m! 5b203 + 6H
++6e +++■ Furthermore, at the second electrode, a reaction expressed by the following reaction formula (■) occurs.

A92SO4+2H”+26.1!2Ag+H2SO4
・=■ Therefore, in the electrolytic solution, the reaction shown by the following reaction formula (■) occurs.

2Sb+3mu92”04+5H20→5b203+6A
9+3H2SO4...■ The antimony ions and silver ions produced in the above reaction formula diffuse into the electrolyte, although in trace amounts. However, minutes N! membrane 3
As a result, the antimony ions and silver ions remain in the vicinity of the sensor, so they do not become electrodeposited on the negative electrode of the lead-acid battery during charging and become a factor that inhibits charging.

When the relationship between the specific gravity of the electrolytic solution and the electromotive force was measured using the specific gravity sensor for lead-acid batteries as described above, the results shown in FIG. 2 were obtained. ! From the results in Figure @2, it can be seen that the relationship between the specific gravity of the electrolytic solution and the electromotive force is almost as in the theoretical formula.

Moreover, this result shows that the lead-acid battery did not change until it reached the end of its service life. Can take measurements.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a specific gravity sensor for a lead-acid battery according to the present invention, and FIG. 2 is a diagram showing the relationship between the specific gravity of an electrolytic solution and electromotive force measured using the sensor. 1...First electrode 2...Second electrode 3...Minimum membrane

Claims (2)

[Claims] (1) a first electrode whose unipolar potential is lower than the hydrogen generation potential;
and a second electrode having a monopolar potential higher than the oxygen generation potential, and each of the electrodes is coated with a separation membrane that allows hydrogen ions and sulfate ions to pass through but does not allow metal ions to pass through. Specific gravity sensor for storage batteries. (2) The specific gravity sensor for a lead-acid battery according to claim 1, wherein at least one of the first electrode and the second electrode is a sulfate salt that is sparingly soluble in the electrolytic solution.