JP4066487B2 - Method for producing lead-acid battery - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for manufacturing a lead storage battery.
[0002]
[Prior art]
Lead-acid batteries are batteries that use lead dioxide as the positive electrode, lead as the negative electrode as the active material, and dilute sulfuric acid as the electrolyte. These electrode plates are filled with paste made of lead powder, sulfuric acid, and water as the main components in a lead alloy grit, aged and dried to form an unformed electrode plate (unformed plate). Is formed and charged by chemical conversion in dilute sulfuric acid to obtain a porous chamber active material suitable for the reaction. Chemical charging includes electrode plate formation in which the electrode plate is formed in a separate battery case from the battery, and battery case formation in which the unformed plate is combined with a separator to form an electrode plate group and housed in the battery case. When the battery plate is discharged, both electrodes produce lead sulfate, and when charged, the original lead dioxide and lead are restored.
[0003]
Due to such material changes due to repeated charge and discharge, the structure of the positive electrode active material generally collapses. Particularly, in the positive electrode, the active material particles fall off and the conductivity decreases, resulting in a decrease in discharge capacity accompanying the cycle. It contributes to life deterioration.
[0004]
[Problems to be solved by the invention]
Especially when left in a discharged state, the lead sulfate crystals are enlarged, making charging difficult and lowering the capacity. In addition, lead sulfate is weakened by the accumulation of lead sulfate and the life characteristics are reduced. It is desirable to charge the battery.
[0005]
To improve such a life factor, a method such as adding an acid-resistant resin binder to the active material is conceivable. In this case, the sulfuric acid passage in the porous body is narrowed by the binder particles, It shows a tendency that the utilization factor and voltage characteristics decrease.
[0006]
The present invention solves the above-described problems, and an object of the present invention is to provide a life improvement method that does not decrease the discharge capacity by avoiding a decrease in utilization rate and voltage characteristics in a lead battery premised on diffusion of sulfuric acid. And
[0007]
[Means for Solving the Problems]
In order to achieve the above object, the present invention is an electrode plate or electrode assembly after conversion charge, to discharge the predetermined quantity of electricity in dilute sulfuric acid containing mannose and sulfuric acid hydrazine, given these batteries in a discharged state this It is characterized by having a discharge leaving step of leaving the circuit open for a time.
[0008]
The present invention is an active material structure excellent in binding force, preferably for discharge, by maintaining the open circuit state for a predetermined time while the discharge state is formed in dilute sulfuric acid containing a lead ion solubility modifier, particularly mannose and hydrazine sulfate, in particular. Is formed.
[0009]
The life improvement effect of the present invention involves the discharge depth and the time for which the circuit is left open. Moreover, this effect cannot be obtained in dilute sulfuric acid in which the above-mentioned solubility adjuster for lead ions is not present. This means that the active material once passes through the form of lead sulfate and requires time to repeat dissolution and precipitation in the presence of the solubility modifier.
[0010]
For the electrode plate formed in the electrolytic solution to which the solubility modifier is added, a similar effect can be obtained even if the discharge is left in the electrolytic solution to which the lead ion solubility modifier is not added. This is because the solubility adjusting agent of lead ions taken into the crystal by adsorption or the like at the time of chemical charging is eluted and acts effectively.
[0011]
As described above, the present invention is based on the change in the electrode plate structure caused by the presence of the solubility adjusting agent for lead ions in dilute sulfuric acid, the predetermined amount of discharge, and the open circuit in the discharged state.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an example of the embodiment of the present invention will be described below.
[0013]
FIG. 1 is a cross-sectional view of a lead storage battery.
1 is a battery case, 2 is a battery case lid, 3 is a positive electrode plate, 4 is a negative electrode plate, 5 is a positive electrode terminal, 6 is a negative electrode terminal, 7 is a separator, and 8 is a safety valve. The separator is impregnated with dilute sulfuric acid in the electrolytic solution.
[0014]
This battery is a battery having a nominal capacity of 3 Ah using two positive electrodes each having a theoretical filling amount of 3 Ah / sheet and three negative electrodes having 2 Ah / sheet as the electrode plates.
[0015]
The above-described battery was constructed using an unformed sheet, and charged again through the chemical charging process, the discharging process, and the open circuit leaving process, and the manufacturing process as a lead battery was terminated.
[0016]
In the embodiment of the present invention, a predetermined discharge is maintained in the dilute sulfuric acid to which the solubility adjusting agent of lead ions such as mannose and hydrazine sulfate is added in the above process, and the open circuit is left open.
[0017]
Ma N'no scan is not a chelating agent, and a lead ion coordinated even in dilute sulfuric acid, has the effect of changing the solubility and activity of lead ions.
[0019]
Hydrazine sulfate promotes the degradation of the secondary lead oxide, a compound that increases the solubility of lead.
[0020]
Effect of the present invention by apply the above components is obtained. The effect of improving the life characteristics by leaving the discharge is widely effective in the range of several ppm to several percent for the above-mentioned additives, and particularly good in the range of 100 ppm to 500 ppm.
[0021]
【Example】
The features and effects of the embodiments of the present invention will be described below by way of examples.
[0022]
( Reference example )
A battery was formed using an unformed plate, formed in dilute sulfuric acid having a specific gravity of 1.15 and adjusted to a specific gravity of 1.3, and then 300 ppm of mannitol was added to the electrolytic solution. This battery was discharged at various discharge depths at a constant current of 0% to 300% with respect to the nominal capacity at 2.3 A, and left in an open state for a predetermined time of 1 hour to 100 hours. These batteries were again charged with 300% of the nominal capacity to produce batteries.
[0023]
For these batteries, discharging at 15 A for 15 minutes and constant current charging at a setting current of 2.3 A setting voltage of 2.45 V and a constant current at a constant voltage of 60 minutes as one cycle, the voltage at the time of discharging for 15 minutes to 1 V The number of cycles to reach was determined as the lifetime of the battery, and the relationship between the discharge depth and the standing time and the lifetime was determined. These batteries are designated as A and C.
[0024]
As a comparison, the lifetime when no mannitol was added to the electrolytic solution left to discharge was determined. Let this battery be B and D.
[0025]
(Example 1 )
When E: Mannose 300 ppm and hydrazine sulfate 300 ppm are added as lead ion solubility adjusters, F: Mannose 300 ppm, G: Ethylenediaminetetraacetate 300 ppm as a chelating agent, discharge depth is 100% of nominal capacity, discharge The lifetime was determined when the subsequent open time was 20 hours.
[0026]
FIG. 2 shows the relationship between the discharge depth and the life when the standing time is 20 hours in the reference example . In the figure, the life is shown as a relative value with respect to the life of the battery not subjected to the discharge leaving operation as 100% (the same applies hereinafter). As is clear from this figure, the battery B of the conventional example discharged in an electrolytic solution not added with mannitol, which is a lead ion solubility modifier, and left in the open circuit, had a reduced life as the depth of discharge increased. Compared with this, in A , the lifetime was increased by leaving the circuit open after discharging.
[0027]
At this time, the discharge depth was effectively 50% or more. If the battery is discharged for 100% or more and left open, the life of the conventional electrolyte is reduced, but in this example , the life characteristics are improved.
[0028]
FIG. 3 shows the relationship between the open circuit leaving time and the life when the discharge depth in the reference example is 100% of the nominal capacity. As a result, the life characteristics rapidly rise after 5 to 10 hours of standing, and the subsequent rise gradually saturates, and the effect appears when left for at least 5 hours.
[0029]
FIG. 4 shows the life characteristics of the battery of Example 1 . This figure when viewed in contrast with the results of FIG. 2 shows that the coexistence of mannose and hydrazine sulfate superior effect than either alone obtained.
[0030]
【The invention's effect】
As described above, the present invention remarkably improves the battery life by discharging in a dilute sulfuric acid electrolytic solution to which lead ion solubility adjustment is added and leaving the circuit open.
[Brief description of the drawings]
FIG. 1 is a schematic cross-sectional view of a battery according to an embodiment of the present invention. FIG. 2 is a diagram showing a relative life ratio according to discharge depths of batteries A and B. FIG. Fig. 4 shows the life ratio. Fig. 4 shows the relative life ratio of the batteries E, F and G when the battery B is 100.
DESCRIPTION OF SYMBOLS 1 Battery case 2 Battery case lid 3 Positive electrode plate 4 Negative electrode plate 5 Positive electrode terminal 6 Negative electrode terminal 7 Separator 8 Safety valve

Claims (1)

An electrode plate or electrode plate group after conversion charge and discharge in an electrolyte containing mannose and sulfuric acid hydrazine, manufacturing method of a lead-acid battery, characterized in that it comprises the step of leaving open at a discharge state.

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