JP2001202988A - Sealed lead-acid battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sealed lead-acid battery having an expanded grid having a satisfactory trickle service a life and capable of restricting an abnormal conditions of the ear of the positive plate. SOLUTION: The distance between the positive and negative plates is set to 1.2 mm or smaller and the cross section of the ear of a homopolar plate per 20-hour rate capacity of the battery is to be 1.9 mm2/Ah of the battery or larger. In addition, it is desirable that the total sum of apparent surface areas of positive plates per 20-hour rate capacity of the battery is set to 26.6 mm2/Ah and that the expanded grid is set to a Pb-Ca-Sn alloy containing 1.0 wt.% of Sn or more.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sealed lead-acid battery used as an emergency backup power source for communication equipment, UPS and the like.

[0002]

2. Description of the Related Art Cast grids have been widely used as grids for the electrodes of sealed lead-acid batteries. Further, in recent years, a so-called expanded lattice body in which a plurality of slits are formed in a rolled sheet made of a lead alloy and the slit portions are developed and extended has been used from the viewpoint of productivity.

Particularly, in order to improve the trickle life in high-rate discharge, a positive / negative electrode plate having the above-described expanded lattice is used, a large electrode plate surface area is secured, and the distance between the positive and negative electrode plates is increased. A configuration for shortening is being studied.

[0004] Since the expanded lattice body using the rolled lead alloy as described above has a fine lamellar rolled crystal in its crystal structure, it is as coarse as the conventional cast lattice body has. The form of oxidative corrosion is different from that of a simple cast structure. That is, the corrosion of the rolled body proceeds uniformly in the direction in which the thickness decreases. In the case of using a Pb-Ca-Sn-based alloy in which the Sn concentration in the lattice alloy is added to about 1.0% by weight or more in consideration of the life in a high-temperature atmosphere, the deformation of the lattice network is suppressed. Therefore, the adhesion between the lattice network and the active material is maintained for a long time. On the other hand, the grid itself continues to be corroded in the direction of reducing its thickness. When the battery in such a state is discharged at a high rate current at a high temperature, the grid ears are cut off, the capacity of the battery is rapidly reduced, and the battery may suddenly reach the end of its life.

[0005]

SUMMARY OF THE INVENTION The present invention suppresses cutting of the grid ears when a sealed lead-acid battery using the above-described conventional expanded grid body is used in a trickle including a high-rate discharge. An object of the present invention is to provide a sealed lead-acid battery having excellent reliability.

[0006]

According to a first aspect of the present invention, there is provided a grid formed by forming a plurality of slits in a rolled sheet made of a lead alloy and expanding and expanding the slits. In a sealed lead-acid battery having a positive electrode plate and an negative electrode plate having an expanded grid body having a mesh portion and a grid lug connected thereto, the positive electrode plate and the negative electrode plate constituting an electrode plate group Distance between 1.2
mm, and the total cross-sectional area of the grid ears having the same polarity is 1.9 mm ² / Ah or more per 20 hour rate capacity of the battery.

The invention according to claim 2 is the invention according to claim 1.
In the sealed lead-acid battery of the invention according to the above description, the sum of the apparent surface areas of the positive electrode plates is 2 per hour rate capacity of the battery.
6.6 mm ² / Ah or more.

[0008] The invention according to claim 3 is based on claim 1.
Alternatively, in the sealed lead-acid battery according to the second aspect of the present invention, the expanded lattice body used for the positive electrode plate is a Pb-Ca-Sn-based alloy containing at least 1.0% by weight of Sn.

[0009]

Embodiments of the present invention will be described below.

First, a cast slab of a Pb-Ca-Sn-based alloy was prepared, and then rolled in multiple stages to prepare a rolled lead sheet. Next, after forming a slit in the rolled lead sheet, the slit forming portion was developed and extended to produce an expanded lattice body 1 shown in FIG. As the alloy composition of this rolled lead sheet, the Ca content is 0.05 to 0.08% by weight, Sn
Those having a content of 0.2 to 1.8% by weight are generally used. This expanded lattice body 1 has a lattice mesh part 2 obtained by developing and expanding a slit forming part,
, And an ear 4 connected to the upper frame 3. Here, the cross-sectional area of the ear 4 is calculated as the product of the thickness (t) of the ear 4 and the width (w) of the ear 4. The grid mesh part 2 is filled with an active material paste (not shown). This active material paste
Generally, it is manufactured by adding sulfuric acid-resistant synthetic resin fibers and various additives to a mixed powder of lead and lead oxide, and kneading with water and dilute sulfuric acid. Particularly, in the paste for the positive electrode active material, a material obtained by adding lead oxide to lead oxide is generally used in consideration of the formation efficiency and the initial capacity characteristics of the storage battery. Further, as the lead mica, a material containing a lower oxide such as lead monoxide is generally used by baking lead monoxide and having a content of 90% by weight of the lead mica.

The expanded lattice body 1 filled with the active material paste has a surface to which a paste paper mainly composed of pulp fibers is stuck and cut to a predetermined size.
Drying is performed at a temperature of about 5 ° C. to produce an unformed positive electrode plate 5 and a negative electrode plate 6. These electrode plates are combined with a glass mat separator 7, and when there are a plurality of electrode plates of the same polarity, the lugs 4 of the same polarity are collectively welded to form a shelf 8 as shown in FIG. , A terminal take-out unit 9 is formed on the shelf 8. In the sealed lead-acid battery of the present invention, the distance G between the positive electrode plate 5 and the negative electrode plate 6 having different polarities is 1.2 mm or less,
In addition, the sum of the cross-sectional areas (t × w) of the ears 4 of the same polarity electrode plate is 1.9 mm ² per 20 hour rate capacity of the sealed lead-acid battery.
/ Ah or more. With such a configuration, it is possible to suppress disconnection of the ear portion when a high-temperature trickle including a high-rate discharge is used.

The sum of the cross-sectional areas is obtained by multiplying the cross-sectional area of the lug per electrode plate by the number of the same-polarity electrode plates.
In the example of FIG. 2, four positive electrode plates 5 and five negative electrode plates 6 constitute an electrode plate group. Therefore, the positive electrode has a value obtained by multiplying the cross-sectional area of the lug 4 of the positive electrode by 4. Similarly, for the negative electrode, the value is obtained by multiplying 5 by the cross-sectional area of the ear part 4 of the negative electrode. In addition, in the above configuration, in particular, the sum of the apparent surface areas of the positive electrode plates in the cell {height of the electrode plate surface × width × 2 (front and back surfaces)} exceeds 26.6 mm ² / Ah per 20 hour rate capacity of the battery. It is preferable to apply this case. When the electrode plate area per battery capacity is larger than the above value, the internal resistance of the battery further decreases,
This is because the duration of the high-rate discharge increases, and the probability of disconnection of the ears increases.

The rolled lead sheet used for the positive electrode grid body has
When the content of n exceeds 1.0% by weight, deformation and elongation of the lattice body due to oxidation corrosion are suppressed, and good adhesion between the lattice body and the active material can be maintained for a long time. From the viewpoint of battery life, such an action is preferable, but on the other hand, even after the battery has been used for a long period of time, the battery discharges for a long time at a high discharge current even in a state where the cross-sectional area of the ear part is reduced by corrosion. Since it is possible, the ears are likely to be disconnected. In such a case, it is particularly preferable to apply the configuration of the present invention as described above.

[0014]

EXAMPLES The structure of the present invention and the trickle life characteristics of the sealed lead-acid battery of the comparative example were evaluated, and the effect of the present invention was clarified. The details are described below.

(Embodiment 1) First, the sealed lead-acid batteries according to the present invention and comparative examples have a nominal voltage of 12 V and a rated capacity of 20 hours at 7 Ah. The sealed lead-acid batteries according to the examples of the present invention and the comparative examples each include four positive plates and five negative plates. The size of each electrode plate is 69 m in height for the positive electrode plate
m, width 45mm, thickness 2.90mm, negative electrode plate height 70
mm, width 45 mm, thickness 1.90 mm. The grids used for these electrode plates were all expanded grids obtained by expanding a rolled lead sheet of a Pb-Ca-Sn-based alloy. The thickness of the rolled lead sheet used in Example 1 was 1.1 mm for the positive electrode and 0.7 mm for the negative electrode. These thicknesses correspond to the thickness of the ear 4 of the positive electrode and the thickness of the ear 4 of the negative electrode, respectively. The positive electrode plate and the negative electrode plate had an active material filling amount of 100 g for the positive electrode and 110 g for the negative electrode per electrode plate group. In the above case, the apparent surface area of the positive electrode plate is 62.1 cm ^{2 on} both sides, and ^{2 in} the electrode plate group.
48.4 cm ² , 3 per 20 hour rate capacity
It corresponds to 5.5 cm ² / Ah. Here, the ear 4 of the negative electrode plate
Is 5 mm (total sum of the sectional areas of the ears of the negative electrode plate is 17 mm).
5 mm ² ), and the total sum of the cross-sectional areas of the negative electrode plate ears per 20 hour rate capacity is fixed at 2.5 mm ² / Ah, and the distance between the positive electrode plate ear cross-sectional area and the distance between the positive electrode plate and the negative electrode plate is changed. Thus, a battery shown in Table 1 was produced. Pb-0.06% by weight Ca-1.0% by weight Sn alloy as a positive electrode grid alloy, and Pb-0.06% by weight Ca-0.25% as a negative electrode grid alloy
A weight percent Sn alloy was used.

[0016]

[Table 1]

Next, the batteries A to I shown in Table 1 were prepared by changing the sum of the apparent surface areas of the positive electrode plates per 20 hour rate capacity. Specifically, from the configuration of four positive electrode plates and five negative electrode plates, which are the number of electrode plates of Battery A to Battery I, the configuration of three positive electrode plates, four negative electrode plates or two positive electrode plates, and three negative electrode plates did. However, the amount of the active material contained in the electrode plate group was 100 g for the positive electrode and 110 g for the negative electrode, which were the same as the batteries shown in Table 1. Table 2 shows the configurations of these batteries.

[0018]

[Table 2]

For the batteries A to U shown in Tables 1 and 2, the trickle life characteristics were evaluated by the following evaluation method.

The test conditions are as follows. <Trickle life test> (1). The test battery in a charged state is discharged at a discharge of 35 A at 25 ° C. to a final voltage of 9.6 V, and the initial capacity is calculated. (2). The battery is charged at a constant voltage of 13.8 V in an atmosphere of 60 ± 2 ° C. for 3 weeks. (3). Confirm the capacity under the condition of (1). (4). The charge / discharge cycle of (2) and (3) is performed, and the cycle is repeated until the discharge capacity becomes 1/2 or less of the initial capacity.
The charging period at this time is defined as a trickle life. Further, the battery after the test was disassembled and inspected, and the state of the positive electrode lug was confirmed. Table 3 shows the results.

[0021]

[Table 3]

As is clear from the results in Table 3, the present invention
According to the configuration, the positive electrode is used in trickle using high-rate discharge.
The thickness of the ears is significantly reduced or the positive ears are cut
Over the long term,
It can be confirmed that the state can be maintained normally. Also, with the positive electrode plate
2 for batteries N and O whose distance between the anode plates is 1.2 mm
The sum total of the positive electrode plate ear cross-sectional areas per 0 hour rate capacity is 1.9.
mm^Two/ Ah battery O is 1.6 mm compared to battery N^Two
/ Ah, the degree of corrosion of the positive electrode ears is
It was getting very bad. The life is remarkably reduced according to the deterioration
Was something. On the other hand, the total ear cross-sectional area per battery capacity
The sum is 2.2mm^Two1.9mm from / Ah ^TwoLow to / Ah
Under the conditions, there was almost no influence on the life reduction. So
To consider the relationship between cross-sectional area and corrosion.
Current density during high-rate discharge increases
I do. Furthermore, the volume of the ear part decreases due to the reduction of the cross-sectional area.
Joule heat generated based on the discharge current
Temperature rise is severe, the temperature of the ears rises and corrodes
It is assumed that the reaction was accelerated. Especially of the present invention
As with sealed lead-acid batteries, the ears are exposed
In the case of a structure in which heat from the ears is difficult to dissipate due to liquid dissolution,
It is presumed that such a phenomenon becomes significant.

(Example 2) Next, in a confirmation experiment performed in Example 1, the Sn content in the positive electrode lattice alloy was examined. For each of the batteries D, E, and F shown in Table 1, the positive electrode grid alloy was Pb-0.06% by weight Ca-0.6.
Batteries V, W, and X shown in Table 4 were prepared in which the percentage by weight was Sn.

[0024]

[Table 4]

The trickle life test performed in Example 1 was performed on the batteries V, W, and X shown in Table 4. In addition, the same disassembly and investigation as in Example 1 was performed on the battery that had completed the life test, and the state of the positive electrode lug was confirmed. Table 5 shows the results.

[0026]

[Table 5]

From the test results of the batteries V, W, X shown in Table 5 and the batteries D, E, F shown in Table 3, when the concentration of Sn in the positive electrode grid alloy was reduced to 0.6% by weight. Indicates that the trickle life of the battery is significantly reduced. The condition of the positive electrode lug was better than that of the batteries D, E, and F. In addition, the positive electrode lattices of the batteries V, W, and X extended remarkably in the vertical direction, and the positive electrode active material was in a state of being lifted from the positive electrode lattice. From these results, when the concentration of Sn in the positive electrode lattice alloy is reduced, it is considered that the battery reaches its life before an abnormality occurs in the positive electrode lug. Therefore, although it is possible to suppress the abnormality at the positive electrode lug, which is the subject of the present invention, it is not the most preferable because the battery life itself is shortened. On the other hand, according to the configuration of the present invention according to claim 3, it is possible to obtain both long battery life and suppression of abnormalities at the positive electrode lug.

In the present embodiment, ordinary Pb-Ca
Although an example using a rolled sheet of a -Sn alloy was described, a Pb-Sn alloy layer containing Sn at a higher concentration than the rolled sheet was formed on the rolled sheet surface by pressing or the like in consideration of overdischarge recoverability. A similar result is obtained in this case.

[0029]

As can be seen from the above description, according to the structure of the present invention, in the sealed lead-acid battery provided with the expanded grid, the trickle life characteristic of high rate discharge is ensured and the occurrence of abnormalities in the positive electrode lug is ensured. And a highly reliable sealed lead storage battery is obtained, and the effect is high.

[Brief description of the drawings]

FIG. 1 is a partial plan view showing an expanded lattice body.

FIG. 2A is a side view of an electrode group; FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Expanded lattice body 2 Grid mesh part 3 Upper frame bone 4 Ear part 5 Positive electrode plate 6 Negative electrode plate 7 Separator 8 Shelf 9 Terminal take-out part G Distance w Width

Claims (3)

[Claims] A rolled sheet made of a lead alloy is provided with a plurality of slits, and an expanded grid body having a grid mesh formed by expanding and expanding the slits and a grid lug connected to the grid mesh. In a sealed lead-acid battery provided with a positive electrode plate and a negative electrode plate, a distance between the positive electrode plate and the negative electrode plate constituting an electrode plate group is set to 1.2 mm or less, and a cross-sectional area of the grid ears having the same polarity. A sealed lead-acid battery having a total sum of not less than 1.9 mm ² / Ah per 20 hour capacity of the battery. 2. The sealed lead-acid battery according to claim 1, wherein the apparent surface area of the positive electrode plate is at least 26.6 mm ² / Ah per 20 hour capacity of the battery. 3. An expanded lattice body used for a positive electrode plate contains Pb—Ca— containing at least 1.0% by weight of Sn.
3. The sealed lead-acid battery according to claim 1, wherein the lead-acid battery is a Sn-based alloy.