JPH05290875A - Sealed lead-acid battery - Google Patents

Abstract

PURPOSE:To provide a battery which is easy to manufacture, having a stable and constant characteristic by filling the required powder substance between electrodes and between electrode groups, and then covering the top of the powder substance with a foamed continuous plastic foam. CONSTITUTION:A granular powder substance 13 of high flowability forming a coarse secondary particle of very fine primary particles coagulated is filled as an electrolytic solution holding member in the space between a positive electrode plate 1 and a negative electrode plate 2 and between electrode body groups which are separated with a separator 3. The upper surface of powder substance 13 is covered with a formed acid-resistant continuous plastic foam 12. A fixed amount of the powder substance in which a fixed amount of the electrolytic solution is injected with the expansion caused at the time of foaming, is sealed in the case where the filled space is different, thereby making a sealed lead-acid battery which is easy to manufacture, having a stable and constant characteristic.

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 There are two types of sealed lead-acid batteries, a retainer type and a gel type, for a sealed lead-acid battery which utilizes a so-called oxygen cycle in which an oxygen gas generated during charging of the battery is absorbed by a negative electrode. The retainer type is a mat-like separator (glass separator) made of fine glass fibers between the positive electrode plate and the negative electrode plate.
Is installed to hold the sulfuric acid electrolyte necessary for battery charging / discharging and to separate the electrodes from each other. Taking advantage of features such as no maintenance, no leakage, and position free, it is portable in recent years. It has come to be used not only as a backup power source for equipment, cordless equipment, and computers, but also as a large stationary battery and for starting the engine of automobiles.

However, the glass separator is a matt made of extra fine glass fibers having a diameter of about 1 micron manufactured by a special method, and is used as a separator for a generally used lead storage battery. It is considerably expensive in comparison, and it is difficult to assemble the battery because it is necessary to strongly press the electrode plate group and install it in the battery case in order to obtain the target battery performance. It had the drawback of being expensive.

Further, in the retainer type sealed lead-acid battery, the sulfuric acid electrolytic solution can be substantially held in the glass separator inserted between the positive and negative electrode plates, so that the amount of electrolytic solution which can be involved in charging and discharging of the battery is small. There is a drawback that the battery capacity, particularly the low rate discharge capacity, is inferior compared to the general open type lead acid battery, which is small and has abundant electrolyte.

On the other hand, the gel type is a sealed lead acid battery in which a sulfuric acid electrolytic solution is gelled with colloidal silica or water glass, but there is still a problem in terms of performance due to the separation of sulfuric acid and the poor migration of sulfate ions. there were.

Therefore, in order to solve the above-mentioned drawbacks, a powder having a higher porosity and a larger specific surface area than that of a lead storage battery active material is directly arranged between the positive and negative electrode plates and around the electrode group, and the powder is formed. In addition, there is proposed a sealed lead acid battery having a structure in which a sulfuric acid electrolytic solution necessary for charging and discharging the battery is held and which is neither the retainer type nor the gel type described above.

However, the sealed lead-acid battery using such powder as an electrolyte holder has the following problems. That is, when the powder is filled in a monoblock battery composed of a plurality of cells, it is convenient to make the filling amount constant because the powder filling is easy and the liquid injection amount can be made constant. However, since the internal volume of the battery case is different for each cell, filling the battery with the powder does not make the filling volume constant, and filling the battery with the powder further increases the weight of the battery. There was also a problem that it took a long time for the liquid. However, if a certain amount of powder is filled in each cell, some cells will have a space in the upper part of the battery case. If a space is created in the battery, the powder moves during the liquid injection or the initial charge, and a cavity is created in the powder layer filled between the electrode plates, so that the expected battery performance cannot be obtained.

The present invention provides means for solving the above problems of a sealed lead-acid battery using powder as a holding body for an electrolytic solution.

[0009]

According to the present invention, an acid resistant plastic foam having open cells is formed by in-situ foaming a synthetic resin on the upper part of the powder filled between the electrode plates and around the electrode plate group. The present invention provides a sealed lead acid battery that solves the above problems.

[0010]

FIG. 1 is a schematic view showing an embodiment in which the sealed lead acid battery according to the present invention is applied to a battery for automobiles.
FIG. 2 is a side view of the main part. In the figure, reference numeral 1 denotes a positive electrode plate in which a positive electrode paste is filled in a grid made of an antimony-free lead alloy or a lead alloy containing a small amount of antimony.

As an antimony-free lead alloy, Ca is
A general lead calcium alloy containing 0.05 to 0.12 wt% and Sn 0.2 to 1.0 wt% can be used. A lead antimony-based alloy may be used as long as hydrous silicon dioxide having a property of adsorbing antimony is used as the electrolytic solution holder.

The antimony content of the lead antimony alloy is preferably Sb 0.7 to 2.0 wt%, particularly 0.7 to 1.5 wt%, and arsenic As is 0.1 to 0.1% as a metal other than antimony.
Add 0.3wt%, tin Sn 0.01-0.5wt%. Adding a very small amount of selenium Se or sulfur S as a nucleating agent can improve the castability and corrosion resistance of the lattice.

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 powder (Pb ₃ O ₄ ) in the powder.

The negative electrode plate 2 is manufactured by filling an ordinary negative electrode paste prepared by adding a shrinkproofing agent such as lignin or barium sulfate to a lattice made of an antimony-free lead alloy. The negative electrode lead alloy is Ca 0.05 to 0.12 wt%, Sn 0.001 to 0.5 wt%
Common lead calcium based alloys including can be used.

As the above-mentioned positive and negative electrode grids, any of cast ones, expanded grids obtained by expanding a lead alloy sheet, punched grids and the like can be used. The paste-filled electrode plate 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 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. Also,
In order to fill the powder between the positive and negative electrode plates, it is necessary to provide a gap between the two electrodes, and for that purpose, a separator with unevenness such as a corrugated separator or an embossed separator is used. Is convenient.

When the powder described later is used as the electrolyte holding body, the powder layer between the electrodes also has a function as a separator. In such a case, the use of the separator can be omitted. is there.

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 produce 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.

After connecting the cells as described above, a fixed amount of the powder 13 is supplied to each cell from the upper part of the battery case 4, and the positive and negative electrode plates and the electrode plate group are connected while vibrating the battery. Fill around.

It is preferable that the powder as the electrolytic solution holder has a high porosity in the filled state, has acid resistance and excellent fluidity of the electrolytic solution and has high fluidity. Diameter 10-40 mm, specific surface area 150-200 m ²
/ G Hydrous silicon dioxide (SiO ₂ · nH ₂ O) fine particles are aggregated to form secondary particles of 50 to 200 μm, and the angle of repose is 30 to 35 degrees. The powder having good fluidity was used.

If the powder has excellent fluidity as described above,
Gravity acceleration of 2 to 4 G and amplitude of 1 to 2 m for filling powder in the battery case
If a vibration of m 3 is applied, it can be densely packed in a short time, and the powder after filling has a porosity close to 90%, which is comparable to that of a glass separator. In this embodiment, the amount of the powder 13 filled was such that the strap 5 could be filled up as shown in FIGS. 1 and 2, but at least the positive electrode plate 1 and the negative electrode plate 2 were formed in the powder layer. The amount should be such that it is buried.

After the powder is filled in this way, an acid-resistant foaming synthetic resin is injected onto the upper surface of the powder 13 to cause foaming, so that the powder 13 has an acid-resistant open cell. Form a layer of plastic foam 12 and powder 13
To fix. At this time, since the plastic foam 12 expands 10 to 40 times in volume as compared with that before foaming, at the time of foaming, a foaming jig 14 as shown in FIG. It is desirable that the plastic foam 12 is formed by pressing the powder 13 so that the plastic foam 12 and the powder 13 can be formed.
There are no cavities between the
However, the problem that the expected performance cannot be obtained due to the movement of particles and the formation of cavities in the powder layer filled between the electrode plates was solved.

In addition to the function of fixing the powder, the plastic foam 12 must be able to release the gas generated during the charging of the battery, the initial charging or the charging during use to the outside. It must have acid-resistant open cells with pores of a size that allows gas or liquid to pass but not powder. In this example, low temperature foaming type phenol was used.

In this way, the plastic foam 12
After fixing the powder 13 with, the battery case lid 8 is welded to the battery case 4,
Attach the exhaust valve 11 to complete the battery. 10 is an exhaust plug.

Next, an experimental example in which the initial performance test and the life test of the sealed lead acid battery according to the present invention are performed will be described. The battery used for the test is a 12V sealed lead-acid battery for automobiles, which has a nominal capacity of 25Ah. Table 1 shows the test results. The life test was conducted under the following conditions. Constant voltage life test condition: Ambient temperature 40 ° C Discharge 25A for 4 minutes Charge 14.8V for 10 minutes (MAX current 25A)

[0026]

[Table 1]

The voltage in the parentheses is for the 5th second. Voltage A is Pb-0.1% Ca for the positive electrode lattice alloy with the powder as the electrolyte holding body.
This is a product of the present invention using -0.5% Sn. B is a retainer type conventional product using the same positive electrode grid alloy as A. The negative electrode was a lead-calcium alloy lattice of Pb-0.7% Ca-0.5% Sn.

As is clear from this experimental example, the initial performance of the product A of the present invention was superior to that of the conventional product B in both the 5-hour rate capacity and the 150 A discharge capacity. This is probably because the amount of the electrolytic solution of the product of the present invention could be kept larger than that of the conventional product and the chemical conversion of the positive electrode plate was improved by mixing lead oxide in the positive electrode paste.

In the life test, the cold cranking current (274
It was discharged at A), and the life was defined as the time when the voltage dropped to 7.2V at 30 seconds. As a result, the battery A of the present invention was twice as excellent as the battery B of the conventional product. Further, it was found that the amount of the electrolyte solution decreased during the life test was small and the sealing reaction efficiency was excellent.

When the battery is disassembled and observed after the life test,
In a sealed lead-acid battery using a conventional glass separator, the positive electrode grid is significantly corroded, and the positive electrode plate is deteriorated beyond the original shape. Since it was fixed, the deformation was slight. It is considered that this is also one of the reasons why the life performance of the product of the present invention was excellent.

As described above, in the sealed lead-acid battery according to the present invention, the electrolytic solution is held by the fine primary particles having a large specific surface area, and the agglomerates of the relatively coarse secondary particles are closely contacted with each other to form a gas. Based on the concept of a new sealed lead-acid battery that uses a passage, it was possible to obtain battery performance and superior sealed reaction efficiency superior to those of the retainer-type sealed lead-acid battery using a conventional glass separator.

As described above, in the sealed lead-acid battery using the powder as a support for the electrolytic solution, primary particles such as plate crystals of calcium silicate other than the hydrous silicon dioxide powder shown in this embodiment are contained. Any fine powder having a large specific surface area and porosity, which aggregates to form secondary particles, and has acid resistance and hydrophilicity can be used.

If the secondary particles are powders which are easily broken, a suitable binder can be used. Further, since it is not necessary to press the electrode plate group, the battery can be easily assembled, and the manufacturing cost of the battery can be significantly reduced because the material used is inexpensive.

Furthermore, since the strap portion of the electrode plate group is exposed in the conventional retainer-type sealed lead-acid battery, the negative electrode strap portion is corroded when the battery is used under conditions where the battery is charged and discharged at high temperature. There were cases. However, in the sealed lead-acid battery according to the present invention, since the whole electrode plate group is buried in the powder layer or the plastic foam, it is one of the great advantages that corrosion does not occur even under such a use condition.

The present invention is conceivable in various modes other than those shown in the embodiments. For example, if the present invention is applied to a tubular lead-acid battery, a sealed lead-acid battery can be easily manufactured.

The conventional tubular lead-acid battery has a serious drawback in that the positive electrode plate is not flat, so that the glass separator cannot be used. Therefore, only the gel-type sealed battery can be manufactured, and the life is short. However, it was found that the production of the battery according to the present invention not only simplifies the production of the battery but also provides a tubular sealed lead-acid battery having excellent life performance.

[0037]

As described above, according to the sealed lead-acid battery of the present invention, it is not necessary to change the powder filling amount and the liquid injection amount according to the variation in the battery cell inner volume for each cell, and a fixed amount of powder is filled. Then
Since the amount of liquid injected is constant and the foamed acid-resistant plastic foam is placed on top of the filled powder, it is easy to manufacture and a stable battery with constant characteristics can be obtained.
Its industrial value is great.

[Brief description of drawings]

FIG. 1 is a schematic view of a sealed lead-acid battery according to the present invention.

FIG. 2 is a side view of a main part of a sealed lead acid battery according to the present invention.

FIG. 3 is a schematic view showing the arrangement of a foaming jig used for manufacturing the battery of the present invention.

[Explanation of symbols]

 1 Positive electrode plate 2 Negative electrode plate 3 Separator 4 Battery case 5 Strap 6 Cell connection part 7 Pole column 8 Battery case lid 9 Exhaust plug mounting port 10 Exhaust plug 11 Exhaust valve 12 Plastic foam 13 Powder 14 Foaming jig

Claims (1)

[Claims] 1. A sealed lead-acid battery using, as an electrolyte solution holder, granular powder having high fluidity, in which fine primary particles are aggregated to form coarse secondary particles. A sealed lead-acid battery, characterized in that it is filled around the electrode plate group and an acid-resistant plastic foam having open cells that are foamed in situ is arranged above the filled powder.