JP3000157B2 - Sealed lead-acid battery - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a sealed lead-acid battery, and an object of the present invention is to provide a sealed lead-acid battery having excellent life performance.

[0002]

2. Description of the Related Art Conventionally, in an open type liquid battery, when deep discharge is repeatedly performed as in a forklift, a clad type in which a cathode active material is wrapped in a tube made of glass or synthetic resin fibers. Generally, a positive electrode plate is used.

Usually, when the positive electrode plate is discharged, Pb of the active material is discharged.
Since O ₂ changes to PbSO ₄ having a large volume, its shape changes greatly as the cycle progresses. Therefore, when deep discharge is repeatedly performed, the bonding force of the positive electrode active material decreases, and the discharge capacity gradually decreases.

It is known that a clad type electrode plate in which a cathode active material is wrapped in a tube can suppress the expansion and fall of the active material, can maintain the binding force of the active material for a long time, and have a long cycle life. I have.

[0005] For the above reasons, a clad type electrode plate is similarly employed as the positive electrode plate in the production of a sealed lead-acid battery having excellent cycle life performance.

As a method for sealing a battery, (1) a so-called retainer type, in which a separator made of fine glass fibers along a positive / negative plate shape is used to impregnate and hold an electrolytic solution, (2) ) A so-called gel type in which the electrolyte is gelled with colloidal silica or the like;
(3) A method in which granular silica is filled between the electrode plates and around the electrode plate group, and the electrode plate, the separator, and the granular silica are impregnated with an electrolytic solution and held, that is, a so-called granular method is generally used. Although it is known, (1) has not been put to practical use because the production cost of the separator is extremely high. In terms of performance, each of (1), (2), and (3) has a smaller discharge capacity than the liquid-type battery, and has a considerably poor life performance. Further, compared with a battery using a paste-type electrode plate, the rate of performance degradation was large, and the superiority using a clad-type electrode plate was not exploited. In order to clarify these reasons, various tests were performed on the gel type battery and the granular type battery, and as a result, the following was found.

[0007] In these sealed lead-acid batteries, the electrolyte is mainly held by gel or granular silica. However, the moving speed of H ₂ SO ₄ in these holders is remarkably higher than that of the liquid type battery. slow. Therefore, the speed at which the electrolytic solution enters the active material is significantly lower than that of the liquid type.
As a result, the following phenomena occur in the battery.

In the closed type, when a clad type electrode plate is used, the amount of the electrolytic solution is extremely small in the portions where the tubes are in contact with each other, as can be seen from the sectional view of the main part shown in FIG. Therefore, the supply of the electrolytic solution to the active material in the portion in contact with the tube is reduced, and the discharge amount is reduced. Observing the state of the cross section of such a positive electrode plate, FIG.
As shown in B, PbSO ₄ which is a discharge product is unevenly distributed.

FIG. 3 is a diagram comparing the distribution of the discharge products (PbSO ₄ ) after the discharge of the clad type electrode plate, wherein A is a battery according to the present invention, B is a conventional sealed battery, and C is a conventional battery. Is a conventional liquid battery.

On the other hand, in a liquid battery, H ₂ SO ₄
H ₂ SO ₄ moves smoothly by convection, which is not available in a sealed battery, so that the tube-to-tube contact portion is not affected by H ₂ SO ₄ even if H ₂ SO ₄ is consumed. Since the power is supplied promptly from the portion, the discharge of the positive electrode plate progresses uniformly and substantially concentrically as shown in FIG. 3C.

From the above results, the reason why the closed type discharge capacity is significantly smaller than that of the liquid type is that the moving speed of H ₂ SO ₄ is slow. The reason why the capacity reduction rate in the liquid type is larger than that in the case is that in the clad type, the vicinity of the tube is hardly discharged. In addition, as a result, it was found that in the sealed battery, the current was concentrated on the active material at a position where discharge was easy, so that the active material deteriorated early and the life performance was reduced.

[0012]

SUMMARY OF THE INVENTION An object of the present invention is to improve the cycle life performance of a clad type sealed lead-acid battery. The gist of the present invention is to provide a tube between tubes of a clad type positive electrode plate. A gap, which is a function of the diameter, thickness, porosity, and distance between the poles and is determined by the following equation, is provided to hold the electrolyte.

A = B × coefficient X × (1.1−0.1 × E)
−2 × C × D A: gap between tubes (mm) B: radius inside tube (mm) C: thickness of tube (mm) D: porosity of tube (%) × 0.01 E: distance between electrodes (Mm) X: 0.29 to 0.75

[0014]

By providing an appropriate gap between tubes and introducing an electrolytic solution into the tubes, a gel type and a granular type battery can uniformly discharge a clad type electrode plate as shown in FIG. 3A. become. As a result, the substantial current density is lower than before, so that the deterioration of the active material can be delayed, and the cycle life performance can be improved.

However, in practice, in order to provide a gap between tubes in the same space, it is necessary to reduce the number of tubes as compared with the prior art, and the amount of active material is reduced, so the gap amount is limited to a certain range. There is a need. Providing a gap between tubes means securing a large amount of electrolyte near the active material, so the diameter, thickness,
A similar effect can be obtained depending on the porosity and the like, and it is considered that the required gap amount also changes when these characteristics are changed. Also, if the distance between the electrodes is changed, the way of supplying the electrolytic solution to the active material is changed, and it is considered that the optimum gap between the tubes also changes.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The battery of the present invention will be described below with reference to the drawings. (Embodiment 1) FIG. 1 is a schematic cross-sectional view of a main part of a closed lead-acid battery electrode group according to the present invention, wherein 1 is a clad positive electrode plate, 2 is a paste negative electrode plate, 3 is a separator, and 4 is a gel electrolyte. 5 is a tube and 6 is a metal core.

First, the following positive plates were manufactured using a Pb-Ca-Sn alloy cored bar and a glass tube having a porosity of 70%, and two positive plates, three ordinary paste type negative plates, and a pulp separator were prepared. Were used to assemble cells with 1.0 and 3.0 mm gap distance. After injecting an electrolytic solution obtained by mixing dilute sulfuric acid and a gelling agent into the solution, a predetermined amount of charge was performed to adjust the specific gravity after charge to 1.30 (20 ° C.). After charging, a safety valve and the like were attached according to a conventional method to produce a battery of about 65 Ah (5 HR).

[0018]

[Table 1] The batteries using these positive plates were discharged at 13 A, and the discharge capacities were examined. The results are shown in FIG. 4 (for a 1.0 mm gap) and FIG. 5 (for a 3.0 mm gap).
Regardless of whether the distance between the electrodes is 1 mm or 3 mm, the discharge capacity has a gap between the tubes, and the discharge capacity is almost the same as that of the conventional battery as long as the coefficient X does not exceed 0.75. From this, it was found that the discharge capacity did not decrease even if the number of tubes was small, provided that at least the coefficient X did not exceed 0.75 and the gap between the tubes was increased.

Next, these batteries were discharged at 20 A × 2.5.
h (DOD 77%), charging 20A x 90%, 6A x 25
% (Total 110%) at a temperature of 50 ° C. for a cycle life test. These test results are shown in FIG. 6 (for a 1.0 mm gap) and FIG. 7 (for a 3.0 mm gap). The coefficient X is in the range of 0.29 to 0.75 within the range of the present invention.
The battery of No. 1 has remarkably improved life performance as compared with the conventional battery. As described above, the reason for this is that if there is a gap between the tubes, as shown in FIG.
It is considered that as shown in A, the reaction was prevented from being concentrated on a specific portion, and the deterioration of the active material was able to be delayed. The reason that the life performance was poor when the coefficient X exceeded 0.75 is probably because the amount of the active material was too small and the discharge became too deep. (Example 2) A so-called granular battery having the same structure as in Example 1 and having granular silica of 50 to 200 µm filled between the electrode plates and around the electrode group was manufactured. The discharge capacity when the distance between the electrodes is 1 mm is shown in FIG. 8 and the life performance is shown in FIG. 9. X is 0.29 ~
In this case, a gap was provided between the tubes so as to be in the range of 0.75. Although not shown here, even when the distance between the electrodes was 3 mm, the battery with the coefficient X of 0.29 to 0.75 exhibited improved life performance.

As a method of providing a fixed gap between the tubes as described above, for example, two porous sheets are wrapped with a thread at the pitch of the tubes or heat-sealed to form a gap between the tube 5 and the tube. In the case of a so-called connecting tube for manufacturing the structure of the connecting portion 7, a thread stitch or a heat seal is applied to the gap between the tubes (connecting portion 7).
Are performed at regular intervals. FIG. 10 shows the shape of this tube.

[0021]

As described above, the clad-type sealed lead-acid battery of the present invention has remarkably superior cycle life performance as compared with the conventional clad-type sealed lead-acid battery, and its industrial value is extremely large.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view of a main part of a sealed lead-acid battery of the present invention.

FIG. 2 is a schematic cross-sectional view of a main part of an electrode group of a conventional sealed lead-acid battery.

FIG. 3 shows PbSO ₄ after discharge of a clad type positive electrode plate
Figure comparing the distribution of

FIG. 4 is a characteristic diagram showing a discharge capacity.

FIG. 5 is a characteristic diagram showing a discharge capacity.

FIG. 6 is a characteristic diagram showing life performance.

FIG. 7 is a characteristic diagram showing life performance.

FIG. 8 is a characteristic diagram showing a discharge capacity.

FIG. 9 is a characteristic diagram showing life performance.

Fig. 10 shows an example of the shape of a tube used in the sealed lead-acid battery of the present invention. 1 Positive electrode plate 2 Negative electrode plate 3 Separator 4 Gel electrolyte 5 Tube 6 Core metal 7 Tube connection part

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-2-168575 (JP, A) JP-A-59-226470 (JP, A) JP-A 61-121665 (JP, U)

Claims (1)

(57) [Claims] 1. A so-called gel-type closed lead using a clad-type electrode plate for a positive electrode plate, a paste-type electrode plate for a negative electrode plate, and dilute sulfuric acid gelled with an inorganic oxide such as silica or alumina as an electrolytic solution. Adjacent tubes in a so-called granular closed lead-acid battery in which a storage battery and granular silica are filled between electrodes and around a group of electrodes, and an electrode plate, a separator, and granular silica are impregnated and held with an electrolyte solution. A sealed lead-acid battery in which a gap is provided between tubes so that a coefficient X in the following equation is in the range of 0.29 to 0.75. A = B × coefficient X × (1.1−0.1 × E) −2 × C × D A: gap between tubes (mm) B: radius inside tube (mm) C: thickness of tube (mm) D: Porosity of tube (%) × 0.01 E: Distance between electrodes (mm)