JP2000195540A - Lead storage battery and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrain charging shortage occurring when a lead-acid battery is used with constant-voltage charging, and service life degradation due to it and to stably provide a service life degradation restraining effect at various depths of discharging. SOLUTION: Rhenium is contained in either a negative electrode active material or an electrolyte of a lead-acid battery, or both the negative electrode active material and the electrolyte. When it is contained in the negative electrode active material, the content of rhenium is set to 0.001-0.01 ppm by weight with respect to the active material. When it is contained in the electrolyte, the content of rhenium is set to 0.003-0.03 ppm by weight with respect to the electrolyte.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lead storage battery and a method for manufacturing the same.

[0002]

2. Description of the Related Art As a method of charging a lead storage battery, there are a constant voltage charging method, a constant current charging method, and a combination of both charging methods. The constant current charging method has the advantage that charging can be completed in a shorter time than the constant voltage charging method,
To prevent overcharging, the charging time must be controlled according to the depth of discharge. The charging method using a combination of the constant voltage charging method and the constant current charging method requires more complicated control. Therefore, as a conventional method of charging a lead storage battery, a method of performing constant voltage charging without controlling charging time has been widely used in terms of the cost of a charger.

[0003] However, in the constant voltage charging method, the charging current value decreases as time elapses from the start of charging, so that it takes time until the battery is sufficiently charged. As a result, sufficient charging time could not be secured during actual use, and in many cases, charging was insufficient. Due to such insufficient charging, the capacity gradually decreases and the service life may be shortened.

As a method for solving such a problem, Japanese Patent Application Laid-Open No. S61-128465 discloses a technique for suppressing insufficient charging by adding an antimony salt to a negative electrode active material to lower the hydrogen overvoltage of the negative electrode. Proposed.

[0005] However, Japanese Patent Application Laid-Open No. S61-1284 discloses this technique.
In the technique proposed in Japanese Patent Publication No. 65, only at the time of charging after a relatively shallow discharge, the effect of suppressing the shortage of charge by the antimony salt added to the negative electrode acting to lower the hydrogen overvoltage was observed. When the discharge deepened, the effect was not remarkable. In actual use, since the battery is discharged at various discharge depths, the effect of adding the antimony salt is not always stably obtained, and the battery may have a short life due to insufficient charging.

[0006]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to suppress the shortage of the battery due to insufficient charging and subsequent repetition of the charging even after discharging at various depths. Things.

[0007]

According to the present invention, as a means for solving the above-mentioned problems, rhenium is contained in either one of the negative electrode active material and the electrolyte or both the negative electrode active material and the electrolyte. It is intended to be a lead storage battery, preferably the amount of rhenium contained in the negative electrode active material is 0.001 to 0.1 ppm per active material weight,
In addition, the amount of rhenium contained in the electrolyte is 0.003 to 0.3 ppm per weight of the electrolyte.

Further, as a method for producing a lead-acid battery containing rhenium in an active material, an active material paste is prepared by kneading a mixed powder of lead and lead oxide with sulfuric acid containing rhenium and water. .

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION (First Embodiment) A lead-acid battery of the present invention has a constant negative electrode active material in which 0.001 to 0.1 ppm of rhenium is present to reduce the hydrogen overvoltage of the negative electrode. The current value when the voltage is applied to the battery is increased to prevent the battery from being insufficiently charged. By including rhenium in the negative electrode, the hydrogen overvoltage can be significantly reduced even in a very small amount. 0.001 ppm per lead anode active material weight for lead-acid batteries
The effect occurs. However, when rhenium is excessively present in the negative electrode, self-discharge is remarkably promoted by generating hydrogen from the negative electrode in the open state of the lead-acid battery, so that the addition of rhenium may be 0.01 ppm or less per negative electrode active material weight. preferable.

Also, rhenium belongs to the manganese group, has high chemical reactivity, and forms oxides of various valences, so that rhenium can be easily added to the negative electrode. The lead-acid battery according to claim 1 or 2, wherein, in the step of kneading a mixed powder of lead and lead oxide with water and sulfuric acid to form an active material paste, rhenium is contained in sulfuric acid. Is effective in obtaining As another method, rhenium oxide is contained in a mixed powder of lead and lead oxide.However, since the amount of rhenium added is very small, a trace amount of rhenium oxide is added to lead and lead acid. It is very difficult to disperse uniformly in a powder mixture with a compound. Therefore, in order to uniformly disperse rhenium in the active material, it is a good means to include rhenium in sulfuric acid which is a kneading liquid of the paste.

(Second Embodiment) A lead-acid battery according to a second embodiment of the present invention contains 0.003 to 0.3 in an electrolytic solution.
It contains rhenium in ppm. Rhenium in the electrolytic solution adheres to the negative electrode active material by charging and discharging, thereby reducing the hydrogen overvoltage of the negative electrode plate and exerting the effect of suppressing insufficient charging. The configuration in which rhenium is contained in the electrolytic solution may be applied to the lead storage battery according to the first embodiment.
In this case, since the elution of rhenium in the negative electrode active material into the electrolyte can be suppressed, the effect of the present invention can be more remarkably obtained.

[0012]

Embodiments of the present invention will be described below in detail.

(Example 1) A mixed powder of lead and lead oxide (hereinafter referred to as lead powder) is prepared from metallic lead. In the embodiment, the composition of the lead powder is 75% by weight of lead monoxide and 25% of metallic lead.
% By weight. Additives such as barium sulfate and sodium ligninsulfonate are added to the lead powder and kneaded with water and sulfuric acid to prepare a negative electrode active material paste. Sulfuric acid containing rhenium was used. By adjusting the rhenium content of the sulfuric acid, negative electrode pastes having different rhenium contents were filled in a grid made of a lead-calcium alloy to prepare an unformed negative electrode plate. This unformed negative electrode plate was formed and charged to form a negative electrode plate.

Next, a mixed powder of lead red and lead monoxide was added to the lead powder and kneaded with water and the above-mentioned rhenium-containing sulfuric acid to prepare a positive electrode active material paste. This positive electrode active material paste was filled in a lead-calcium-tin alloy positive electrode lattice to prepare an unformed positive electrode plate. This unformed positive electrode plate was subjected to chemical charging to form a positive electrode plate.

The combination of the negative electrode plate, the glass mat separator and the positive electrode plate having various rhenium contents described above
A sealed lead-acid battery of 0 Ah was produced. 2 for electrolyte
Dilute sulfuric acid having a specific gravity of 1.310 at 0 ° C. was used. In addition, anhydrous sodium sulfate was added to this electrolyte at 5 g / liter in consideration of capacity recovery after overdischarge. Table 1 shows the rhenium content in the negative electrode active materials of these sealed lead-acid batteries.

[0016]

[Table 1]

The batteries shown in Table 1 were subjected to a cycle life test in which the charging voltage was lowered so that the batteries became insufficiently charged under the following conditions.

(Cycle test conditions) Temperature: 25 ± 2 ° C. Charging: Charging at a constant voltage of 6.9 V (2.3 V / cell) (maximum current 0.3 CA) for 12 hours Discharging: Final voltage at a current of 0.25 CA 1. Discharge cycle to 1.75 V / cell Cycle: The above charge-discharge is repeated as one cycle. FIG. 1 shows the battery voltage at the time of constant voltage charging after the first cycle of discharge for the lead storage batteries of the present invention, the comparative example, and the conventional example. And the current.

FIG. 2 shows the transition of the 0.25 CA capacity per cycle for the lead storage batteries of the present invention, the comparative example, and the conventional example.

As shown in FIG. 1, in the batteries 3 to 6 in which rhenium is 0.001 ppm or more in the negative electrode active material, the rhenium content in the conventional battery 1 and the negative electrode active material is 0.0005 ppm.
The charging current value at the end of charging is larger than that of the battery of ppm. Therefore, the lead storage batteries 3 to 6 in which the amount of electricity used for charging contains rhenium according to the present invention in an amount of 0.001 ppm or more in the negative electrode active material are compared with the battery 1 of the other conventional example and the battery 2 of the comparative example. There were many.

From the results shown in FIG. 2, it was confirmed that the batteries 3, 4, and 5 of the present invention had better cycle life characteristics than the batteries of the conventional example and the comparative example. This is because the conventional battery 1 and the rhenium content were 0.0005 p.
In the battery 2 of the comparative example of the pm, the charge was insufficient due to the constant voltage charge in the cycle life test, and the capacity was reduced in each charge / discharge cycle.
Batteries 3, 4 and 5 according to the present invention containing 1 ppm contained a sufficient amount of electricity at the time of charging because the current value at the time of constant voltage charging was increased by reducing the hydrogen overvoltage of rhenium at the negative electrode. The capacity did not deteriorate even when the discharge cycle proceeded. On the other hand, in the battery containing 0.2 ppm of rhenium, the current value at the time of constant voltage charging rises, but since the amount of rhenium contained is large, the capacity is deteriorated by forming a local battery with rhenium as the negative electrode. It is.

Example 2 In Example 2, the cycle life characteristics of a lead-acid battery having a structure in which rhenium was contained in an electrolytic solution were evaluated. 6V1 as in Example 1 using the negative electrode plate, positive electrode plate and separator used in Example 1.
A sealed lead-acid battery of 0 Ah was produced. As the electrolytic solution, the diluted sulfuric acid used in Example 1 containing various concentrations of rhenium was used. As the negative electrode plate, both those containing rhenium and those not containing rhenium were used. Table 2 shows the configurations of these batteries.

[0023]

[Table 2]

The batteries shown in Table 2 were subjected to a cycle life test under the same conditions as in Example 1. The result is shown in FIG. From the results shown in FIG. 3, the rhenium content in the electrolytic solution was reduced to 0.
It can be seen that the battery of the example of the present invention with 003 to 0.3 ppm shows excellent cycle life characteristics as compared with other batteries. The charging characteristics of the batteries 3 and 4 of the present invention shown in FIG.
Similarly to and 5, since the terminal current at the end of charging was increased, rhenium in the electrolytic solution was attached to the negative electrode plate and the hydrogen overvoltage of the negative electrode was reduced, so that a sufficient amount of charged electricity could be secured and insufficient charging was suppressed. It is considered something. In addition, it was confirmed that the battery 11 in which rhenium was contained in both the electrolytic solution and the negative electrode active material exhibited better cycle life characteristics than the batteries of the other examples of the present invention. This is presumed to be because the inclusion of rhenium in the electrolytic solution suppressed the transfer of rhenium from the negative electrode to the electrolytic solution and more stably obtained the effect of reducing the hydrogen overvoltage of rhenium.

(Embodiment 3) Next, in Embodiments 1 and 2, the batteries 4, 10 and 11 of the present invention and the conventional battery 1
And a battery 13 of a comparative example in which an antimony salt was added to the negative electrode active material. In the battery 13 of the comparative example, antimony sulfate was added during kneading of the negative electrode active material paste. The content of antimony sulfate based on the weight of the negative electrode active material is 5
It was set to 0 ppm. Other configurations of the battery 13 of the comparative example are the same as those of the battery 1 of the conventional example. Cycle life tests were performed on these batteries for each depth of discharge. The discharge rate was varied as a parameter of the depth of discharge. This is because when the discharge rate is high, the depth of discharge is small even at the time of complete discharge, and when the discharge rate is low, the depth of discharge at the time of complete discharge is deep. These results are shown in FIG. Regarding Charge 1 of the conventional example, undercharging occurred at any discharge rate, and the life was shortened. Battery 13 of Comparative Example in which antimony salt was added to the negative electrode active material
In the case of, good life characteristics were exhibited in a region with a high discharge rate, that is, a region with a relatively shallow depth of discharge, but at a low discharge rate, that is, at a deep depth of discharge, the battery was insufficiently charged and the life was shortened. On the other hand, all the batteries of the present invention were able to obtain relatively stable life characteristics even when the depth of discharge was changed. The reason for this is presumed that during deep discharge, antimony was coated on the negative electrode active material and lost its activity.

[0026]

As described above, according to the present invention, it is possible to suppress insufficient charging when constant-voltage charging is used and the deterioration of cycle life characteristics due to this. Since this effect can be obtained stably even at various discharge depths, it is industrially extremely useful.

[Brief description of the drawings]

FIG. 1 is a diagram showing a battery voltage and a charging current characteristic of a lead storage battery according to an example of the present invention, a conventional example, and a comparative example in Example 1 during constant voltage charging after 0.25 CA discharge.

FIG. 2 is a diagram showing the cycle life characteristics of the lead storage batteries according to the present invention example, a conventional example, and a comparative example in Example 1.

FIG. 3 is a diagram showing cycle life characteristics of lead storage batteries according to the present invention example, a conventional example, and a comparative example in Example 2.

FIG. 4 is a diagram showing cycle life characteristics of the lead storage batteries according to the present invention example, the conventional example, and the comparative example in Example 3 according to the depth of discharge.

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor ▲ Yoshi ▼ Hideo Naga 1006 Kadoma, Kazuma, Osaka Matsushita Electric Industrial Co., Ltd. F-term (reference) 5H003 AA04 BA03 BB02 BB04 BD04 5H016 AA02 BB06 EE01 HH01 5H028 AA01 AA06 FF04 HH01 HH02

Claims (4)

[Claims] 1. A lead-acid battery characterized in that one of the negative electrode active material and the electrolyte or both the negative electrode active material and the electrolyte contains rhenium. 2. The lead-acid battery according to claim 1, wherein the amount of rhenium contained in the negative electrode active material is 0.001 to 0.1 ppm based on the weight of the negative electrode active material. 3. The amount of rhenium contained in the electrolyte is:
3. The lead-acid battery according to claim 1, wherein the content is 0.003 to 0.3 ppm per weight of the electrolyte. 4. A method for producing a lead storage battery in which a mixed powder of lead and lead oxide is kneaded with water and sulfuric acid to form an active material paste, wherein the sulfuric acid contains rhenium. Manufacturing method of storage battery.