JP2002075371A - Manufacturing method for positive electrode plate for lead-acid battery and lead-acid battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method for a positive electrode plate for a lead-acid battery improving the using rate of an active material for the positive electrode plate without reducing the serviceable life performance and maintenance characteristics. SOLUTION: This manufacturing method for the positive electrode plate is provided with, at least, a process of manufacturing paste using the positive electrode active material, peroxyboric acid sodium, and dilute sulfuric acid and a process filling a collector with the paste manufactured in the above process.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a lead storage battery.

[0002]

2. Description of the Related Art Lead-acid batteries are inexpensive and have stable performance, and are therefore used in a wide range of fields such as backup power sources for vehicles and UPS. However, there is a disadvantage that the energy density is lower than that of a nickel metal hydride battery or a lithium ion battery. One of the causes is that the utilization rate of the positive electrode active material is low, and it has been desired to improve the utilization rate of the active material. Various additives have been studied for the purpose of improving the utilization rate.

For example, as described in JP-A-61-171062, graphite (carbon additive) is added to a positive electrode active material, and JP-A-04-14758 and JP-A-03-276561 are disclosed. As described in
An n-compound, an Sb compound, or the like is added to the active material to improve the conductivity of the active material, increase the surface area of the active material, control the pores in the active material, and improve the utilization rate of the active material.

In addition to the above, Japanese Patent Application Laid-Open No. 2-68857
No. 2, a lead-acid battery paste prepared using lead powder to which zirconium phosphate was added was converted into dilute sulfuric acid containing a predetermined phosphoric acid derivative, then immersed in phosphoric acid, and ZrP was added to the positive electrode active material. There is also known a technique for providing a long-life lead-acid battery having a large discharge capacity by making the lead-acid battery exist.

[0005]

However, additives that have the effect of improving the utilization rate of the positive electrode active material, on the other hand, promote the softening or falling off of the active material and reduce the life performance,
The added element precipitates on the negative electrode plate to reduce the hydrogen overvoltage, and as a result, there is a problem that the liquid reduction increases and the maintenance characteristics deteriorate.

An object of the present invention is to solve the above-mentioned problems, and an object of the present invention is to provide a lead-acid battery in which the active material utilization of the positive electrode plate is improved and the life performance and maintenance characteristics are not deteriorated.

[0007]

According to a first aspect of the present invention, there is provided a process for producing a paste using at least lead powder, sodium peroxoborate and dilute sulfuric acid, and collecting the paste produced in the process. And a step of filling the body with a positive electrode plate for a lead-acid battery.

According to a second aspect of the present invention, in the method for producing a positive electrode plate for a lead storage battery according to the first aspect, the amount of sodium peroxoborate with respect to the lead powder is 0.1 to 5% by weight. It is.

According to a third aspect of the present invention, there is provided a lead-acid battery including a positive electrode plate manufactured by the manufacturing method according to the first or second aspect.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION In the method for producing a positive electrode plate according to the present invention, a lead is mixed with sodium peroxoborate as a positive electrode active material, diluted sulfuric acid is added, and a paste is prepared according to a standard method. It can be implemented by filling the electric body. The lead storage battery using the positive electrode plate manufactured by this method has an improvement in the utilization factor and the life performance as compared with the lead storage battery manufactured by the conventional method. Note that the current collector is a general term for an electrode substrate holding a positive electrode active material and having a current collecting function, and a grid-like or foil-like thing is usually used.

It is not yet clear why the addition of sodium peroxoborate improves the utilization rate of the positive electrode active material. However, sodium peroxoborate generates H ₂ O ₂ when dissolved in water. Because it is an oxidizing agent, sodium peroxoborate is decomposed while generating H ₂ O ₂ during paste preparation, and at that time, reactivity with lead powder increases, and interaction with unactivated active material crystals is likely to occur It can be considered. Therefore, even after chemical formation,
In the positive electrode active material to which sodium peroxoborate is added, the interaction between the active material and boron or borate ions is maintained, the crystal structure of PbO ₂ and PbSO ₄ is distorted, and the growth of the crystal is inhibited, and the active material is coarsened. It is believed that the compound has an effect of suppressing the formation of the active material and forming and maintaining an active material having excellent reactivity.

Further, in the positive electrode plate of a lead storage battery, a phenomenon is observed in which lead sulfate is generated at the time of discharge and the conductivity of the active material is reduced. This decrease in the conductivity of the active material is one factor that causes a decrease in the discharge voltage. However, boron compounds (borides) generally have excellent conductivity, and boron compounds (borides) are used in active materials to which sodium peroxoborate is added. It is also conceivable that the oxide plays a role in suppressing an increase in the resistance of the active material during discharge. As for the amount of sodium peroxoborate, which is considered to improve the utilization rate and life performance due to the combined effects of the above effects, if the amount is less than 0.1% with respect to the lead powder, the utilization rate is improved. And the effect of improving the life performance is insufficient, and if it is 5 wt% or more, the volume energy density of the positive electrode decreases, so that 0.1 to 5 wt% is preferable.

The present invention is not limited to a specific lead-acid battery, but can be applied to any type of lead-acid battery such as a sealed type, a liquid type, and a clad type. Further, the effect of the present invention does not change even when lead powder to which lead red is added is used.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on embodiments. First, sodium perborate to lead powder (NaBO ₃ · 4H ₂ O)
Was added to the lead powder in an amount of 1 wt%, and then predetermined amounts of water and dilute sulfuric acid were added and mixed to prepare a positive electrode plate paste. Next, this paste was filled into a lead alloy current collector to obtain a positive electrode plate.

For comparison, a paste containing no sodium peroxoborate (NaBO ₃ .4H ₂ O) and boric acid (H ₃ BO
₃ ) A paste to which 1 wt% was added and a paste to which 1 wt% of sodium borate (Na ₂ B ₄ O ₇ .10H ₂ O) were added were prepared, and similarly filled into a current collector to obtain a positive electrode plate. .

Separately from the above, a lignin and barium compound, a predetermined amount of water and dilute sulfuric acid are added to and mixed with lead powder to prepare a paste for a negative electrode plate, which is filled in a lead alloy current collector to form a negative electrode. I got a board.

A sealed lead-acid battery of 2V-6Ah was manufactured by using each of these four positive plates, five negative plates and a glass fiber separator. Subsequently, diluted sulfuric acid was injected, the battery was chemically formed, and then subjected to a test. FIG. 1 shows a list of these lead storage batteries.

These lead-acid batteries were discharged at a discharge current of 0.1 CA.
(0.6 A) and 1 CA (6 A) were tested for capacity. The result is shown in FIG. The batteries with boric acid and sodium borate (C, D) and the additive-free product (B) had almost the same capacity, but the battery with sodium peroxoborate (A) had a capacity of about 8 at low rate discharge. %, And about 15% in the high-rate discharge, the capacity was larger than B, C and D.

Further, these lead storage batteries were subjected to a life test. In the life test, 50% of the rated capacity was discharged at 1/3 CA current (2 A) at 40 ° C.
The test was performed under the condition of charging 20%. In the life test, the discharge capacity was 50% of the rated capacity in a capacity test at a current of 0.1 CA (0.6 A) performed every 50 cycles.
The life was defined as the time when the following was reached.

The number of life cycles of each lead storage battery and 0.1 CA at 500 cycles when the additive-free product (B) reaches the end of its life
The discharge capacity is shown in the rightmost column of FIG. As shown in the middle row of FIG. 3, the life of the additive-free product (B) is 500 cycles, the life of the battery (C) to which boric acid is added is 550 cycles, and the life of the battery (D) to which sodium borate is added. The battery (A) to which sodium peroxoborate was added had a capacity of 80% of the rated capacity even at the time of 500 cycles when the non-added product (B) had a life of 500 cycles.
The above conditions were maintained, and the life was 800 cycles, which was significantly longer.

FIG. 4 shows the amount of liquid reduction of the battery during the life test. Battery containing sodium peroxoborate (A)
Was equivalent to that of the additive-free product (B), there was no problem of electrolyte drying during use of the battery, and there was no adverse effect on the sealing and maintenance characteristics.

[0022]

As described above, according to the present invention, there is provided a lead-acid battery having an advantage that the active material utilization rate of the positive electrode plate is improved and the life performance and the maintenance characteristics are good.

[Brief description of the drawings]

FIG. 1 is a table showing the contents of a battery.

FIG. 2 is a diagram showing a capacity test result.

FIG. 3 is a table showing life test results.

FIG. 4 is a table showing the amount of liquid reduction during a life test.

Claims (3)

[Claims] 1. A process for producing a paste using at least lead powder, sodium peroxoborate and dilute sulfuric acid, and a process for filling the paste produced in the above process into a current collector. A method for producing a positive electrode plate for a lead storage battery. 2. The method for producing a positive electrode plate for a lead storage battery according to claim 1, wherein the amount of sodium peroxoborate based on the lead powder is 0.1 to 5% by weight. 3. A lead-acid battery comprising a positive electrode plate manufactured by the method according to claim 1.