JPH11339788A - Lead-acid battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reconcile the higher efficiency of chemical conversion charging and the prevention of deep reduction in charge and discharge cycle life by setting one mesh of the expanded metal grating of a positive electrode plate to a specified area, and including red lead of a specified ratio in a mixed powder of lead and lead oxide formed by kneading a paste to be applied with water and diluted sulfuric acid. SOLUTION: When a mixed powder of lead and lead oxide in an active material paste contains 10-30% of red lead, chemical conversion efficiency of red lead, improvement in initial capacity characteristic and prevention of a significant reduction in life in repeat of deep charge and discharge are realized. It is formed of reciprocating type or rotary type, and the area per mesh controlled by the length and transverse expanding length of the slit extended in the mesh of an expanded metal grating is set to 40-150 mm<2> , so that the reduction in deep charge and discharge cycle life can be remarkably suppressed. The expanded metal grating frame is preferably twisted with the grating frame as the axis, so that the adhesion between the active material and the grating frame can be kept even after the progress of softening of the positive electrode active material, and the effect can be more enhanced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention belongs to the technical field of lead-acid batteries, and more particularly to a technique for achieving both the efficiency of formation and charging of a battery using a paste-type electrode plate and the improvement of the life characteristics in a relatively deep charge and discharge. It is about.

[0002]

2. Description of the Related Art A lead-acid battery generally comprises a mixture of lead powder and lead oxide, water and dilute sulfuric acid as main components, to which short fibers made of synthetic resin or the like and other additives are added. Fill the paste obtained by the combination into a casting grid or continuous porous body,
A paste-type electrode plate that is cut into the shape of an electrode plate as needed and dried to form an electrode plate is often used. In general, this electrode plate is further combined with a separator to constitute an electrode plate group, and after being incorporated in a battery case, added with dilute sulfuric acid and then subjected to formation charging to give a function as a battery.

In this formation step, the efficiency of the formation charge of the positive electrode plate is lower than that of the negative electrode plate. In order to avoid the loss of power and time due to this, conventionally, a technique of mixing high-grade lead oxide, that is, Pb ₃ O _4, into a mixed powder is generally known.

[0004] This is because the lead red contained in the mixed powder is the red litharge, that is, Pb
This is because β-PbO ₂ is easily generated by chemical charging together with O, and has an effect of improving the chemical conversion efficiency. Furthermore, β-PbO ₂ produced from this lead
Has an effect of improving the battery discharge characteristics after formation charge because it has higher conductivity and reactivity with sulfuric acid than α-PbO ₂ having another crystal form.

As described above, it has been found that the above-described effects can be obtained by applying lead tin to the paste electrode plate, but the battery life is shortened particularly when the battery is subjected to deep charge / discharge. . This is particularly due to the property of β-PbO ₂ , and the bonding force between active materials is likely to decrease as deep charge / discharge is repeated. Therefore, the active material is likely to soften and fall off when the active material is repeatedly charged and discharged with large expansion and contraction, and when using such lead powder containing lead red as an active material material, a grid structure that holds the active material must be used. It turns out that special considerations are needed. Further, such a fall of the active material is remarkable particularly when an expanded lattice is used as the lattice. This is considered to be related to the fact that the expanded grid has a smoother surface than the conventional cast grid.

[0006]

SUMMARY OF THE INVENTION In the present invention, a mixed powder containing lead and lead is used for a paste positive electrode plate, and a reduction in the deep charge-discharge cycle life, which has been a conventional problem in improving the efficiency of chemical charging. Therefore, the electrode plate is intended to be compatible with the efficiency of chemical charging, which is an advantage of this electrode plate.

[0007]

In order to solve the above-mentioned problems, a lead-acid battery according to the present invention comprises a paste obtained by kneading mixed powder of lead powder and lead oxide powder with water and dilute sulfuric acid on an expanded lattice. In a lead-acid battery provided with a positive electrode plate coated with, the area of one square of the expanded lattice is 40 mm ² or more and 150 mm ² or less, and the content of lead red in the lead powder and the lead oxide powder is reduced. It is 10 to 30%, preferably, the lattice bone forming the expanded lattice is twisted around the lattice bone as an axis.

[0008]

Embodiments of the present invention will be described below.

First, with respect to lead gallium to be added to lead powder, which is a raw material of an active material, first, a lead powder produced by the Barton method was further calcined to produce a lead oxide containing about 70% of gem.
A mixed powder of ordinary lead and lead oxide is mixed with this lead oxide to make the content of lead red to 10 to 30%. If the content of lead galleria is less than 10%, the effect of improving the chemical conversion efficiency and initial capacity characteristics of the ginseng cannot be obtained. If the content exceeds 30%, deep filling is performed even if sufficient consideration is given to the lattice structure. The life is remarkably reduced by repeated discharge. Further, even if lead-tan is added in excess of 30%, the effect of improving the formation efficiency and the initial discharge characteristics becomes saturated.
0% is appropriate.

Next, an active material paste was prepared by kneading the mixed powder containing lead ginseng with water and dilute sulfuric acid together with additives such as short fibers according to a conventional method.

The present invention uses the following expanded grid as the grid for filling the above paste. That is, a plurality of slits are formed in a zigzag shape in parallel with the longitudinal direction of a lead alloy sheet such as a lead-tin-calcium alloy, and then the slits are developed and expanded to produce an expanded lattice. As a method of putting a slit in this lead alloy sheet,
It was manufactured by a so-called reciprocating method by reciprocating a die corresponding to a slit, or by a so-called rotary method of forming a slit by rotating a disk-shaped blade provided with a convex processing blade on its circumference. In any of the methods, the area of the expanded grating can be controlled by the slit length and the horizontal development length when the slit is developed and extended in the horizontal direction. In the configuration of the present invention using the mixed powder containing 10 to 30% of lead, by setting the area of the square to 40 to 150 mm ² , the effect of suppressing a reduction in life in a deep charge / discharge cycle is remarkably exhibited. Was found. In addition, the effect is that if the size of the grain is increased beyond 150 mm ² , the life in a deep charge / discharge cycle is sharply reduced, so the lead tin content in the mixed powder and the grain area of the expand are reduced. At the same time, it is necessary to sufficiently obtain the effects of improving the formation efficiency and the initial capacity characteristics of the lead by suppressing the reduction in the life in a deep charge / discharge cycle.

As for the method of manufacturing the expanded grid used in the present invention, the expanded grid formed by the rotary method is more effective in obtaining the effects of the present invention than the reciprocating method described above. The reason for this is considered to be the difference between the lattice bone shapes of the reciprocating method and the rotary method. That is, as shown in FIG. 5, the reciprocating expanded lattice basically has almost no twist in the lattice bone 1 and has a simple flat surface, whereas the rotary system used in the present invention has a lead sheet. As shown in FIG. 4, when slits are formed in the slits 2, irregularities 4, 4 'are formed in the slits 3 alternately in the thickness direction of the lead sheet. When the slit portion 3 is unfolded and extended in the direction of arrow A shown in FIG. 5, that is, in the width direction of the sheet, the slit portion 3, that is, the portion that becomes the lattice bone 5 with the irregularities 4, 4 'as vertices is indicated by arrow B in FIG. As described above, since the shape is twisted around the lattice bone, the adhesion between the active material and the lattice bone 5 is more favorably maintained even after the softening of the positive electrode active material has progressed.

[0013]

Examples of the present invention will be described below.

First, the lead powder produced by the Burton method as described above was further fired to produce a lead oxide containing about 70% of lead. A mixed powder of ordinary lead powder and lead oxide powder is mixed with this lead oxide, and the content of lead red is 0, 5, 10, and
Nine types including 15, 25, 30, 35, and 40% were kneaded with sulfuric acid and water according to a conventional method to obtain various pastes. The first area of the grid is 20mm ² , 40m
m ² , 80 mm ² , 110 mm ² , 150 mm ² , 17
The grid was filled so as to be 0 mm ² . Incidentally figure one lattice shape area of 150 mm ² squares of the grid 1
FIG. 1A shows a lattice shape of 40 mm ² , and FIG. The weight of the lattice is set to 40 g regardless of the area of one lattice, and the alloy composition of the lattice is P
Various types of positive electrode plates were obtained using a Sn alloy containing 0.07% by weight of b and 1.20% by weight of Ca and two types of expanded lattices of a reciprocating type and a rotary type as lattice types. A nominal voltage of 12 V and a rated capacity of 48 composed of 5 positive electrodes and 6 negative electrodes per cell using each of the prepared positive plates.
Ah (5-hour rate discharge) lead-acid batteries were each manufactured.

In order for these batteries to exhibit expected performance, the formation state of the positive electrode requires that about 90% or more of PbO ₂ be formed in the positive electrode active material. The quantity of electricity was as shown in FIG. 2 and this hardly depended on the area of one of the grids or the grid shape by the reciprocating system or the rotary system.

Next, as shown in Table 1, these batteries were divided into a reciprocating type and a rotary type as shown in Table 1, and the grids corresponding to the comparative example and the embodiment of the present invention were prepared for each one area. The batteries having the following were classified.

[0017]

[Table 1]

The batteries shown in Table 1 were subjected to a life test under the following conditions in which the depth of discharge was as deep as 40%, and the life characteristics were evaluated.

The life test conditions include an ambient environment temperature of 40
The charge / discharge cycle of 20 A discharge (1 hour) and 14.8 V constant voltage charge (maximum current 25 A, 2 hours) was repeated in ° C., and the discharge voltage at 30 seconds at 300 A discharge was measured every 40 cycles. The voltage at the 30th second is 7.
The time when the voltage fell below 2 V was regarded as the life.

FIG. 3 shows the results of the life test. As a result of the decomposition of the battery after the life test, the cause of the deterioration was that most of the batteries fell off the grid due to softening of the positive electrode active material.

As is evident from FIG. 3, the life characteristics tend to be shorter as the content of lead-tin increases, but when the content of lead-tin is 30% or less, the area of one grid of the grid is reduced. In the range of 40 to 150 mm ² , the range could be kept within 85% under the condition of using the same grid as compared with the case of the lead-tin content of 0%. When the size of one of the grids exceeded 170 mm ² , the life was extremely shortened, and was reduced to 70% or less as compared with the case where the content of lead tin was 0%. In addition, both the reciprocating system and the rotary system showed the same tendency, but comparing the reciprocating system and the rotary expanding lattice showed that the rotary system had better life characteristics. This is considered to be because the contact with the positive electrode active material was maintained more favorably after the softening of the active material because the lattice structure was twisted and more complicated in the rotary method.

The one grid having a square area of 30 mm ² had poor life characteristics, but this was because the grid area of one grid was too small for the same grid weight and the positive grid was This is because bone erosion has become a dominant factor in lifespan and has led to lifespan.

According to FIG. 3 described above, the expanded lattice
One leg area of the body is 40mm ^TwoMore than 150mm^Two
Lead storage with a positive plate below and containing 10-30% of lead
It can be seen that the life cycle of the battery is excellent.

[0024]

As described above, according to the present invention, lead-acid is added to the positive electrode active material to improve the efficiency of the formation charge, and the life characteristic in deep charge / discharge, which is a drawback, is almost reduced. Its industrial value is great because it can be maintained without any harm.

[Brief description of the drawings]

FIG. 1 is a main part front view showing an example of a lattice shape used in an embodiment of the present invention.

FIG. 2 is a graph showing the relationship between the amount of lead red contained in a lead compound of a positive electrode sheet and the amount of electricity charged for formation.

FIG. 3 is a graph showing the relationship between the lead tin content in the lead powder and lead oxide powder used for the positive electrode, the area of one grid of the grid, and the battery life characteristics.

FIG. 4 (a) is a perspective view of a lead sheet at the time of expanding processing by a rotary method. FIG. 4 (b) is an enlarged side view of a main part of an expanded lattice bone shown in FIG.

FIG. 5 (a) is a front view of a conventional expanded lattice bone portion by a reciprocating method. (B) An enlarged front view of a lattice bone surrounded by a dotted line in (a).

[Explanation of symbols]

 1,5 lattice bone 2 lead sheet 3 slit part 4,4 'unevenness

Continuation of the front page (72) Inventor Kazuyoshi Yonezu 1006 Kazuma Kadoma, Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd.

Claims (2)

[Claims] 1. A lead-acid battery provided with a positive electrode plate coated with a paste obtained by kneading lead and lead oxide powder with water and dilute sulfuric acid on an expanded lattice, wherein one area of the expanded lattice is Is 40mm ² or more and 150mm
² or less, and the lead and lead oxide powder contains 10 to 30% of lead. 2. The lead-acid battery according to claim 1, wherein the lattice bone forming the expansion lattice is twisted around the lattice bone.