JP3482671B2 - Sealed lead-acid battery - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a sealed lead-acid battery. 2. Description of the Related Art A sealed lead-acid battery, in which oxygen gas generated from a positive electrode is recombined with a negative electrode plate during charging of the battery, has heretofore been provided with an electrolyte retaining material between the electrode plates. A separator made of a certain fine glass fiber (hereinafter, referred to as a glass separator) is inserted, and a so-called retainer battery in which an electrode plate and a glass separator hold an electrolytic solution, and the electrolytic solution are colloidal with fine silica particles to be non-fluidized. There were two types of gel batteries. In recent years, a granular sealed battery has been proposed in which a granular inorganic powder (hereinafter referred to as inorganic powder) is filled in a battery, and an electrode plate, a separator, and an inorganic powder are impregnated and held in an electrolyte. ing. This battery can hold the electrolyte even in the inorganic powder filled around the electrode group, so it can hold a larger amount of liquid than the retainer type battery, and as a result, has the advantage of having a large low rate discharge capacity. ing. In addition, since the electrode plate is pressed uniformly and strongly from the surroundings, it has the advantage of suppressing the elongation of the lattice and improving the life performance. Further, the inorganic powder, which is an electrolyte holder, has an advantage that it is very inexpensive as compared with a glass separator. Furthermore, since the transfer of sulfuric acid in the inorganic powder is remarkably faster than in the gel type battery, the high rate discharge capacity has an advantage that it is larger than that of the gel type battery. However, as a result of conducting various tests, it was found that the separator used in this granular battery greatly affects the life performance. That is, since the electrolytic solution is limited in the granular battery, it is considered that if the electrolytic solution impregnated in the electrode plate and the separator is selectively reduced, the discharge capacity is affected. SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems and provides a sealed lead-acid battery which is inexpensive and has excellent discharge performance and life performance. In the so-called granular sealed battery using the body, the average pore size is
In other words, a separator having a size of 1 μm or more and an average pore size of the inorganic powder or less is used. Hereinafter, the present invention will be described with reference to examples. A positive electrode and a negative electrode grid made of a Pb-Ca-Sn-Al-based alloy were filled with ordinary positive and negative electrode pastes, respectively, and then aged to produce an unformed electrode plate. The electrode group has three positive electrode plates, four negative electrode plates, and an average hole diameter of 0.5, 1, 10, 20, 40, 50 μm between each electrode plate.
The separator adjusted to be m was inserted. As the material of the separator, a glass fiber is manufactured by wet papermaking, and the average pore diameter is changed by changing the fiber diameter. The thickness of the separator used was 1 mm, which was the same as the gap between the positive electrode plate and the negative electrode plate, with the electrode plate group inserted into the battery case with a pressing force of 20 kg / dm ² . After assembling the electrode group and inserting it into the battery case,
Granular silica having an average pore diameter of 10, 20, and 40 μm was densely filled by vibration around the electrode group in the battery. Thereafter, the electrolyte was injected, and through a known procedure, the electrolyte had a specific gravity of 1.30 (20 ° C.) and a rated capacity of 25 Ah (5 hR).
(A, B, C) were manufactured. FIGS. 1 and 2 show a schematic view and a longitudinal sectional view, respectively, of a battery according to the present invention. In the figure, 1 is a positive electrode plate, 2 is a negative electrode plate, 3 is a separator, 4 is a battery case, 5 is a battery case lid, 6 is a granular silica powder, 7 is a silica powder 6 fixed around the electrode plate group. The open-cell phenolic resin foam 8 is an exhaust valve. Note that the average pore size is 1% of the total pore size in the pore size distribution determined by the mercury intrusion method.
It means the hole diameter corresponding to the hole amount of / 2. For example,
If the total pore size is 80%, the pore size corresponding to 40% of the pore size is determined as the average pore size by integrating from the largest pore size. Thus, a granular battery using separators having different average pore sizes was manufactured. For comparison, a conventional retainer-type battery (battery No. 1) using a glass separator having an average pore diameter of 19 μm without being filled with granular silica.
D) was also produced. First, after discharging these batteries at 5 A to check their capacities, these batteries were discharged at a test temperature of 50 ° C. at a test current of 3 hR at 80% of the rated capacity, and charged and discharged in a pattern of charging 120% of the discharge amount. It was subjected to a cycle life test. Table 1 shows the test results. [Table 1] As is clear from the table, the discharge capacity of each battery was almost the same regardless of the type of silica or separator used. However, comparing the life performance,
Batteries using the 0.5 μm separator having the smallest average pore size (Batteries No. A-1, B-1, and C-1) are different from the conventional retainer battery regardless of the average pore size of the granular silica. The life performance is remarkably inferior. In addition, a granular battery (battery No. A-) in which the average pore size of the separator is larger than the average pore size of the granular silica.
5, no. B-5, no. Also in the case of C-5), the life performance was inferior to that of the retainer type battery. However, a battery (battery No. A) using a separator having an average pore size of 1 μm or more and a granule silica having an average pore size of not more than 1 μm according to the present invention.
-2, No. 2; A-3, no. A-4, no. B-2, N
o. B-3, no. B-4, no. C-2, no. C-
3, No. C-4) has a better life performance than the conventional retainer type battery. In order to clarify the cause, a battery having the same configuration was disassembled after 200 cycles, and the distribution of the amount of electrolyte held in the electrode plate, the separator, and the granular silica in the battery was examined. In a battery using a separator having an average pore diameter of 0.5 μm (Battery Nos. A-1, B-1, and C-1), the amount of electrolyte in the negative electrode plate is considerably smaller than that of the retainer type. Had become. This means that the average pore size of the negative electrode plate is generally 1
It is considered that the reason why the life performance was reduced was that the electrolyte held on the negative electrode plate was absorbed by the separator because the average pore size of the negative electrode plate was larger than the average pore size of the separator. A battery using a separator having an average pore size larger than the average pore size of the inorganic powder (battery No. A)
-5, no. In B-5 and C-5), the amount of liquid retained in the separator was significantly reduced. This is probably because the electrolyte held by the separator was absorbed by the surrounding inorganic powder and the electrode plate. In the battery using the separator according to the present invention, neither the negative electrode plate nor the separator leaked, and only the amount of the retained liquid of the surrounding granular silica was significantly reduced. It is considered that the life performance was good. The reason why the capacity of the retainer type battery decreased relatively early was due to the elongation of the lattice and the deterioration of the performance of the positive electrode plate due to corrosion. In this test, glass fiber was used as the material of the separator. However, the effect is not changed even if an acid-resistant separator having the above-mentioned pore diameter is used regardless of the material. As is apparent from the above example, the sealed lead-acid battery according to the present invention has an average pore diameter of the separator of 1 μm.
The use of the separator having the average pore diameter of the inorganic powder within the range described above can greatly improve the life performance as compared with the conventional retainer type battery, and its industrial value is very large.

[Brief description of the drawings] FIG. 1 is a schematic view of a sealed lead-acid battery of the present invention. FIG. 2 is a longitudinal sectional view of the sealed lead-acid battery of the present invention. [Explanation of symbols] 1 Positive electrode plate 2 Negative electrode plate 3 separator 4 Battery case 5 Battery case lid 6 silica powder 7 Foam 8 Exhaust valve

Claims (1)

(57) [Claim 1] A sealed lead-acid battery in which silica or alumina-based granular inorganic powder is filled around an electrode plate group and impregnated with and held by an electrolytic solution. , Wherein the average pore size of the separator is 1 μm or more and the average pore size of the inorganic powder or less.