JPH06150961A - Sealed lead-acid battery - Google Patents

Abstract

PURPOSE:To improve the discharge performance and life performance without increasing the battery volume by filling the powder having the preset standard in gaps between positive electrode plates and negative electrode plates and on the periphery of an electrode plate group, and fixing the electrode plate group. CONSTITUTION:A sealed lead-acid battery is provided with (m) positive electrode plates 2 and (n) negative electrode plates 1, where m=n or m=n+1 and the powder 14 having the preset porosity and specific surface area is filled in gaps between the positive electrode plates 2 and the negative electrode plates 1 and on the periphery of an electrode plate group. A sufficient quantity of a sulfuric acid electrolyte required for the charge/discharge of a battery is impregnated in the powder 14 and a group of the electrode plates 1, 2. The powder 14 having high porosity when filled, acid resistance, excellent electrode absorbing force, and high fluidity is preferable, and the granular powder coagulated with fine grains of moisture-containing silicon dioxide having the primary grain size of 10 to 40mum and the specific surface area of 150-200m<2>/g into the secondary grains of 50-200mum is used as an example.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improved sealed lead acid battery.

[0002]

2. Description of the Related Art Conventional lead-acid batteries are generally m
One positive electrode plate, m + 1 negative electrode plate, and 2m separators are superposed, and electrode plates of the same polarity are connected by welding to form a unit cell. By connecting a plurality of unit cells, a predetermined voltage is applied. It constitutes a module battery.

In the unit cell, the number of the negative electrode plates is one more than the number of the positive electrode plates. It is preferable that the separators are in contact with the front and back sides of the positive electrode plate in order to prevent the positive electrode active material from softening and falling off during the charge / discharge cycle. This is because it is advantageous. Also, since a good high-rate discharge performance is required for automobile batteries and the like, a configuration in which the number of negative electrode plates that limit the high-rate discharge capacity is one more than that of the positive electrode plates is suitable.

However, in recent years, in batteries for repeated deep discharge cycles such as lead batteries for electric vehicles, the performance is improved by securing a large amount of the positive electrode active material that limits the 3-hour rate discharge capacity within a limited volume. It has become an indispensable element in making it happen.

For this reason, a method of increasing the amount of the positive electrode active material in the unit cell by constructing the same number of positive electrodes and negative electrodes or increasing the number of positive electrode plates by one more than the negative electrode plates can be considered. However, the positive electrode plate having the surface not contacted with the separator is severely deteriorated and has a drawback that the life performance is deteriorated.

[0006]

The present invention fills a gap between a positive electrode plate and a negative electrode plate and a periphery of an electrode plate with a powder having high porosity and a large specific surface area, and is necessary for charging and discharging a battery.
A sufficient amount of sulfuric acid electrolytic solution is substantially impregnated and held in the powder and the electrode plate group, and the number of positive electrode plates m and the number of negative electrode plates n.
Is a structure in which m = n or m = n + 1, a sealed lead-acid battery having excellent discharge performance and life performance is obtained.

[0007]

EXAMPLES The present invention will be described below based on examples. FIG. 1 is a schematic diagram showing an embodiment in which the sealed lead acid battery according to the present invention is applied to a battery for an electric vehicle. In the figure, the positive electrode plate 2 is a positive electrode plate in which a grid made of an antimony-free lead alloy or a lead alloy containing a small amount of antimony is filled with a positive electrode paste. As an antimony-free lead alloy, calcium Ca 0.05 to 0.12 wt%, tin Sn 0.2
A general lead calcium system containing 0 to 1.0 wt% can be used. Depending on the battery application, the Sn content should be 1.5-5.0.
Aluminum Al may be added in an amount of about 0.001 to 0.02 wt% in order to adjust the wt% and stabilize the Ca content during casting.

The amount of antimony Sb added to the lead antimony-based alloy is preferably Sb 0.7 to 2.0 wt%, particularly 0.7 to 1.5 wt%, and arsenic As is 0.1 to 0.3 as a metal other than antimony.
wt% is added. In order to improve the chargeability after deep discharge
Add 0.01 to 0.5wt% Sn or add 0.003 to 0.003% selenium Se, sulfur S, copper Cu, etc. to improve castability and corrosion resistance.
It is also effective to add about 0.03 wt%.

As the positive electrode paste to be filled in the positive electrode grid, a general paste prepared by kneading lead powder with dilute sulfuric acid can be used, but in order to improve the chemical conversion property of the positive electrode plate and the battery performance, It is preferable to mix lead tin (Pb ₃ O ₄ ) in the lead powder.

The negative electrode plate 1 is manufactured by filling an ordinary negative electrode paste prepared by adding an expander such as lignin or barium sulfate to a lattice made of an antimony-free lead alloy. The lead alloy of the negative electrode grid is Ca 0.05 to 0.12 wt%, Sn 0 to
A general lead calcium based alloy containing 0.7 wt% and Al 0 to 0.02 wt% can be used.

As the positive and negative electrode grids described above, any of cast ones, expanded grids obtained by expanding a lead alloy sheet, punched grids and the like can be used. The electrode plate filled with the paste should be aged in a room at 30 to 50 ° C before use. Aging of the positive electrode plate is particularly important for battery performance.

Reference numeral 3 is a synthetic separator inserted between the positive electrode plate and the negative electrode plate. Any separator having a small thickness and porosity and a low electric resistance can be used, but a separator having an excessively small pore size is not preferable because oxygen gas hardly permeates and the oxygen absorption reaction by the negative electrode is hindered.

Further, in order to fill the powder between the positive and negative electrode plates, it is necessary to provide a gap between the both electrode plates. For that purpose, a corrugated separator, an embossed separator or the like is provided with irregularities on the surface. It is convenient to use a separate separator. If the powder described below is used as the electrolytic solution holder, the powder layer between the electrodes also has a function as a separator, and in such a case, the use of the separator can be omitted.

The positive electrode plate, the negative electrode plate, and the separator described above are stacked, and the positive and negative electrode plates are separately welded to form an electrode plate group, which is inserted into the battery case 4. In the one using the conventional glass separator, it was very difficult to insert into the battery case because the electrode plate group had to be strongly pressed, but in the present invention it is not necessary to press the electrode plate group so that the insertion is not possible. It's easy.
After inserting the electrode group into the battery case, the cells are connected. In the figure, 5 is a strap, 6 is an inter-cell connecting portion, and 7 is a pole.

Next, the battery case lid 8 is welded to the battery case 4. Here, the battery case lid 8 is provided with an exhaust chamber 9 and a powder filling port 10, an exhaust valve 12 is disposed above the exhaust chamber 9, and an air-permeable porous plate 13 is disposed below the exhaust valve 12. There is. The exhaust valve 12 has a function of opening when the internal pressure of the battery rises and closing when reducing the internal pressure of the battery, and any generally used valve such as a cap valve, a ring valve and a plate valve can be used.

The perforated plate 13 is for releasing the gas generated during the charging of the battery, the initial charging or the charging during use to the outside, and allows the gas and the liquid to pass through, but does not pass the powder. It is made of an acid-resistant open-cell porous body having pores of a size, for example, a sintered body of foamed phenol or alumina.

If the lower end of the perforated plate 13 is arranged close to the upper end of the electrode plate group, the liquid injection time can be shortened when the electrolytic solution is injected prior to the initial charging. That is,
When the porous plate is brought close to the upper end of the electrode plate group, the injected electrolytic solution is first absorbed by the electrode plate and spreads around, so that the liquid injection time can be greatly shortened.

After assembling the lead-acid battery having the above structure,
A certain amount of the powder 14 is supplied from the filling port 10 and is filled between the positive and negative electrode plates and around the electrode plate group while applying vibration to the battery.
After filling the powder, sealing is performed using the sealing plug 11.

It is to be noted that the powder as the electrolytic solution holder is preferably one having a high porosity in a filled state, an acid resistance and an excellent electrolytic solution absorbing ability and a high fluidity. particle size of 10 to 40 millimicrons and a specific surface area 150 to 200 m ²
/ g of water-containing silicon dioxide (SiO ₂ · nH ₂ O) particles aggregate
A granular powder forming secondary particles of 50-200 microns was used. This powder has excellent fluidity, and it can be packed tightly in a short time if the powder is filled in the battery case with vibration of gravity acceleration of 2 to 4 G and amplitude of 1 to 2 mm. It is possible to fill even uneven places without gaps. Also,
The powder after filling has a porosity close to 90%, comparable to a glass separator.

When initially charging the battery thus assembled, the exhaust valve 12 is first removed and a predetermined amount of sulfuric acid electrolyte is injected. The injected electrolytic solution passes through the perforated plate 13, passes through the powder below it, and is absorbed by the positive and negative electrode plates, the separator, and the powder around it. When the lower end of the porous plate 13 is provided close to the upper end of the electrode plate group as described above, the liquid injection is completed in a shorter time. The initial charging is performed with the exhaust valve 12 attached. Although the electrolyte surface rises due to gassing during charging, the electrolyte surface is trapped in the exhaust chamber 9, so that the electrolyte solution does not leak to the outside even if an overflow prevention jig is not mounted as in the conventional case.

Next, the results of the initial performance test and life test of the sealed lead acid battery according to the present invention will be described.
The battery tested was a 12V sealed lead acid battery for electric vehicles and had a 3-hour nominal capacity of 50 Ah. Table 1 shows the test results. Regarding the life test, discharge was 16.7A for 144 minutes (DOD 80%), charge was 16.7A for 115 minutes.
After 2 minutes, two-stage charging was performed at 5A for 144 minutes. The life criterion was the time when the capacity reached 40 Ah.

[0022]

[Table 1]

In Table 1, A and B are those in which powder is used for the electrolytic solution holder, B is a battery having the structure according to the present invention, C is a retainer type conventional product having the same electrode plate structure as A, and D is the present invention. It is a retainer type battery having the same electrode plate configuration as the product B. In order to make the distance between the positive and negative electrode plates and the length of the electrode plate group of the batteries used in the test the same, for the batteries B and D, the thickness of the positive electrode plates located at both ends of the electrode plate group was about 80%.

From this experimental example, the 3-hour rate discharge capacity is D>B>
The order was C> A. The retainer type battery with the same electrode plate structure had a larger discharge capacity than the battery using the powder as the electrolyte holder because the porosity of the glass separator was larger than that of the powder, It seems that the amount of retentate was large.

The life performance was in the order of B>A>D> C.
When disassembling and observing the battery after the life test, the conventional retainer batteries C and D using the glass separator have significant corrosion of the positive electrode grid and deterioration of the active material, and are particularly located at both ends of the electrode plate group of the battery D. The active material of the positive electrode plate was becoming muddy.
On the other hand, in the product B of the present invention, the electrode plates were three-dimensionally fixed by the filled powder, and the corrosion of the positive electrode grid and the deterioration of the active material did not proceed so much, and the electrode plates were positioned at both ends. No significant difference was observed between the positive electrode plate and the central positive electrode plate in the degree of lattice corrosion and deterioration of the active material.

[0026]

As described above in detail, in the sealed lead-acid battery of the present invention, the positive electrode plate is fixed by filling the gap between the positive electrode plate and the negative electrode plate and the periphery of the electrode plate group with powder. Even in a configuration in which is located outside the electrode plate group, deterioration of the positive electrode plate can be prevented. That is, it is possible to improve discharge performance and life performance without increasing the battery volume, and its industrial value is very large.

[Brief description of drawings]

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

[Explanation of symbols]

 1 Negative Electrode Plate 2 Positive Electrode Plate 3 Separator 4 Battery Case 8 Battery Case Lid 9 Exhaust Chamber 10 Powder Filling Port 11 Sealing Plug 12 Valve 13 Perforated Plate 14 Powder

Claims (1)

[Claims] 1. The number m of positive electrode plates and the number n of negative electrode plates are m = n or m = n + 1, and have a high porosity and a large specific surface area in the gap between the positive electrode plate and the negative electrode plate and around the electrode plate group. A sealed lead-acid battery, which is characterized in that it is filled with a powder, and a sufficient amount of sulfuric acid electrolyte necessary for charging and discharging the battery is impregnated and held in the powder and the electrode plate group.