JPH09231996A - Manufacture of sealed lead acid battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sealed lead acid battery having high superior electric discharging performance and also having a superior long life by a method wherein a paste paper sheet adhered with specified aqueous solution is adhered to either a positive plate or a negative plate. SOLUTION: The manufacturing of a sealed lead acid battery is carried out such that after a paste paper sheet coated with aqueous solution of sodium silicate at its surface is applied, an aged and dried electrode plate and a glass fiber separator are combined to each other to constitute a group of electrode plates. The paste sheet adhered to the surface of the electrode plate has no acid resistive characteristics, it may be decomposed or melted and eliminated while being immersed in electrolyte. However, sodium silicate coated on the paste paper sheet is changed into gelation and left at the surface of the electrode plate. With such an arrangement as above, a contact between the electrode and the separator is kept well so as to keep a dispersion of electrolyte.

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, and more particularly to an improvement of a sealed lead acid battery used for high rate discharge applications.

[0002]

2. Description of the Related Art Recently, a sealed lead-acid battery has been used as an emergency backup power source such as an uninterruptible power supply (hereinafter referred to as UPS). Since this type of sealed lead acid battery is used in buildings and the like, it is required to improve the space efficiency of the battery and improve the high rate discharge performance. The high rate discharge performance is dealt with by using a thin electrode plate grid to increase the number of electrode plates in a cell having a specified size and reduce the current density per electrode plate. However, since the Pb-Ca-Sn alloy that is generally used as the electrode plate material has a limit in thinning by casting, in recent years, the electrode plate grating is manufactured by the expanding process. Acrylonitrile-butadiene-styrene copolymer (hereinafter referred to as ABS resin) is generally used as the battery case material, and its wall thickness is
2-3 mm considering heat dissipation, moldability, strength, cost, etc.
It has been.

[0003]

However, when such a sealed lead-acid battery is used as a backup power source, the moisture in the electrolytic solution is dissipated by passing through the resin portion of the battery case when left for a long time, and the electrolytic solution is discharged. Due to the decrease in the product, the separator contracted and the repulsive force was reduced. As a result, the contact between the separator and the electrode plate cannot be sufficiently taken, diffusion of sulfuric acid required during discharge is hindered, and the concentration of sulfuric acid in the electrolytic solution becomes non-uniform, so that the electrode plate deteriorates early, and especially The rate discharge performance was deteriorated. Further, when it is installed in a place where temperature control is difficult, heat cannot be sufficiently diffused and the battery temperature rises. Therefore, it is required to improve the heat resistance of the battery. Although the dissipation of water in the electrolytic solution can be suppressed by increasing the thickness of the battery case, it causes an increase in cost and deterioration of heat dissipation. Also, by increasing the compressibility of the separator, it is possible to improve the liquid diffusion and improve the trickle life, but under high temperature environment, rather, the battery case is deformed, which reduces the repulsive force of the separator. However, the high rate discharge performance of the battery deteriorates. An object of the present invention is to solve these problems and to provide a sealed lead acid battery having excellent high rate discharge performance and excellent trickle life.

[0004]

The method for manufacturing a sealed lead-acid battery of the present invention is a combination of a plate and a glass fiber separator, which are obtained by pasting a paste paper coated with an aqueous solution of sodium silicate on the surface and then drying it. Make up a group of plates. The paste paper attached to the surface of the electrode plate does not have acid resistance, so it decomposes or dissolves when it is immersed in an electrolytic solution and disappears.However, the sodium silicate applied to the paste paper gels and forms on the surface of the electrode plate. To remain. The remaining gel-like silicic acid intervenes between the electrode and the separator to maintain good contact between the two and maintain the diffusion of the electrolytic solution. Further, by using polypropylene having a low water vapor permeability as the battery case material and having a wall thickness of 2 mm or more, a decrease in the electrolytic solution is suppressed and the repulsive force of the separator is maintained well. As a result, it is possible to obtain a sealed lead-acid battery that is excellent in high rate discharge and life characteristics.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The method for manufacturing a sealed lead-acid battery of the present invention comprises a step of pasting a paste paper having an aqueous solution of sodium silicate on a positive electrode plate or a negative electrode plate, and aging and drying the positive electrode plate or the negative electrode plate. It includes a step of performing. Further, it is preferable to include a step of inserting an electrode group including the positive electrode plate, the negative electrode plate and a separator mainly composed of glass fiber into a polypropylene battery case having a thickness of 2 mm or more at a portion in contact with outside air. . As a result, the amount of residual liquid in the electrolyte can be kept constant for a long period of time, and pressure changes due to constant deformation of the battery case or deformation of the battery case during use can be reduced. Can be achieved.

Further, it is preferable that the grids of the positive electrode plate and the negative electrode plate are expanded. This makes it possible to reduce the thickness of the electrode plate, increase the number of electrode plates constituting the cell, increase the reaction area, and reduce the current density of the electrode plate. Further, the electrode plate interval can be narrowed and the resistance of the electrolytic solution can be lowered. Also,
The positive electrode plate, the negative electrode plate, and an electrode group including a separator mainly composed of glass fiber are inserted into the battery case so that the repulsive force of the separator in a dry state is 20 to 60 kg / dm ^2. It is preferable to include the step of inserting. The repulsive force of the separator in the initial dry state is 20 to 6
When the amount is 0 kg / dm ² , the repulsive force of the separator can be sufficiently maintained even when the amount of the electrolytic solution is reduced.

Further, the main component of the paste paper is preferably natural cellulose. By using a paste paper mainly composed of non-acid resistant natural cellulose, the cellulose part is dissolved in the battery, but the sodium silicate applied to the cellulose surface acts as gel silicic acid between the electrode plate and the glass fiber separator. It is possible to make a good contact between the two and make the diffusion of the electrolytic solution uniform. Further, dilute sulfuric acid electrolytic solution is injected into the battery case in which the electrode group is inserted to perform chemical conversion, and the remaining electrolytic solution is adjusted to 85 to 95% of the theoretical void volume of the separator. It is preferable to include a step. This allows
The life characteristics of efficient discharge can be improved. As described above, the present invention can provide a lead storage battery capable of high-rate discharge and having an improved trickle life.

[0008]

Embodiments of the present invention will be described below in detail with reference to the drawings.

[Example 1] Calcium content 0.08
%, And a lead alloy sheet with a tin content of 1.1% was expanded to form a lattice. A paste paper was laid under the grid, the grid was filled with lead paste, and then the paste paper was placed on the grid. This was attached by pressing with a roller. Here, the paste paper to be attached to both sides of the lattice is made of natural cellulose fiber with a basis weight of 15 g /
The paper was made to have a size of m ^2, and the surface thereof was coated with an aqueous sodium silicate solution containing 20% silicic acid anhydride. This was aged and dried to obtain a positive electrode plate having a thickness of 1.7 mm. For the negative electrode, a grid body obtained by expanding a lead alloy sheet having a calcium content of 0.08% and a tin content of 0.6% is used, and the same sodium silicate aqueous solution as the positive electrode is applied to both sides of the grid body. Crimp with a roller,
A negative electrode plate having a thickness of 1.3 mm was produced.

Using the positive electrode plate and the negative electrode plate thus produced, the sealed lead acid battery shown in FIG. 1 was produced as follows. A separator 2 having a thickness of 1.0 mm and a density of 0.16 g / cm ³ , which is mainly composed of glass fibers having a fiber diameter of about 2 μm, is bent into a U shape, and the positive electrode plate 1 obtained as described above is covered from both sides. Sandwiched between. Separator 2
Using four positive electrode plates 1 and five negative electrode plates 3 sandwiched in between, these are alternately stacked and the ears of the positive electrode plate 1 and the negative electrode plate 3 are respectively welded and electrically connected to form a cell. An electrode group was prepared. Next, the electrode plate group obtained as described above was inserted into a polypropylene battery case 5 having a wall thickness of 3 mm in contact with the atmosphere. The repulsive force of the separator 2 in the dry state at this time was set to 40 kg / dm ² . Then, the adjacent cells were electrically connected in series by the inter-cell connection body 4, and the lid 6 was heat-welded to the battery case 5 for sealing.
Dilute sulfuric acid having a specific gravity of 1.25 was poured into the battery case 5 and an electric current of 2.
Battery case formation was performed at 4 A for 60 hours, the final electrolyte specific gravity was 1.31, and the residual liquid amount was 290 g / cell, 12 V, 24
A sealed lead-acid battery of Ah was produced. Example 1-1
Battery.

In a sealed lead acid battery similar to the battery of Example 1-1, a sealed lead acid battery was prepared by using a 3 mm thick ABS resin battery container in contact with the atmosphere instead of the polypropylene battery container. It was made. However, the lid 6 and the battery case 5 were bonded with an epoxy resin adhesive. Here, the repulsive force of the separator 2 in a dry state when the electrode plate group was inserted into the battery case 5 was set to 40 kg / dm ² as in the battery of Example 1-1. This is the battery of Example 1-2.

In a sealed lead acid battery similar to the battery of Example 1-1, a sealed lead acid battery was prepared by using paste paper to which sodium silicate was not applied. Here, the repulsive force of the separator 2 in the dry state when the electrode plate group was inserted into the battery case 6 was set to 40 kg / dm ² as in the battery of Example 1-1. This is the battery of Comparative Example 1-1.

In a sealed lead acid battery similar to the battery of Example 1-2, a sealed lead acid battery was prepared using paste paper to which sodium silicate was not applied. Here, the repulsive force of the separator 2 in the dry state when the electrode plate group was inserted into the battery case 5 was set to 40 kg / dm ² as in the battery of Example 1-2. This is the battery of Comparative Example 1-2.

For these four types of batteries, six for each, 60
A trickle life test was performed in which a constant voltage charge of 13.8 V was performed in an atmosphere of ° C and a relative humidity of 10%, and a capacity test was performed every three weeks at a discharge current of 72 A. At the same time as the life test, the amount of electrolyte dissipated was measured from the change in battery weight. The results are shown in FIGS. 2 and 3, respectively.

Comparing the battery of Example 1-1 and the battery of Comparative Example 1-1, both of which used a polypropylene battery case, the battery of Example 1-1 using paste paper coated with sodium silicate was used. Shows superior characteristics to the battery of Comparative Example 1-1 in which the paste paper coated with sodium silicate is not used. Similar effects were confirmed by comparison between the battery of Example 1-2 and the battery of Comparative Example 1-2, both of which used an ABS resin battery case. As a result of disassembling and analyzing the battery after the life test, the battery of Example 1-1 using the paste paper coated with sodium silicate and Example 1
In both batteries, the natural cellulose fiber itself of the paste paper was dissolved by dilute sulfuric acid and disappeared, but gel-like silicic acid remained on the surface of the electrode plate. That is, the first embodiment
In the batteries No. 1 and No. 1-2, the gel-like silicic acid forms a coating layer on the surface of the electrode plate, so that good contact between the separator and the electrode plate is maintained, the internal resistance is low, and the diffusion of the electrolytic solution is low. Therefore, it is considered that the battery has excellent life compared with the batteries of Comparative Examples 1-1 and 1-2 which do not use the paste paper coated with sodium silicate.

Further, the battery of Example 1-1 using the polypropylene battery case has a much longer life than the battery of Example 1-2 using the ABS resin battery container. Similarly, the battery of Comparative Example 1-1 using the polypropylene battery case has a longer life than the battery of Comparative Example 1-2 using the ABS resin battery container. This is about 1 / compared to ABS resin, as is clear from the change in weight of the battery shown in FIG.
It is considered that the use of the polypropylene resin having water vapor permeability of 20 as the battery case material can suppress the dissipation of water in the electrolytic solution to the outside of the battery. From this result, it is understood that the battery life is improved by using polypropylene as the battery case material. In the above example, the thickness of the battery case at the portion in contact with the outside air was 3 mm, but it was confirmed that the same effect can be obtained if the thickness is 2 mm or more. Also, in terms of strength and moldability, there is no problem if the wall thickness is 2 mm or more.

Example 2 Using the same battery as in Example 1-1, the battery life against the repulsive force of the separator was examined. This is for a battery in which the repulsive force of the separator when inserting the electrode group into the battery case was changed, 60 ° C, relative humidity 1
After constant voltage charging of 13.8V in 0% atmosphere,
The capacity was inspected at a discharge current of 72 A every three weeks, and the life was defined when the capacity reached 60% of the initial value. FIG. 4 shows the results. From the figure, it can be seen that the repulsive force of the separator is a factor that determines the life of the sealed lead acid battery. In particular, when the repulsive force of the separator is less than 20 kg / dm ² , even if sodium silicate is present on the surface of the electrode plate, the contact with the separator cannot be sufficiently maintained, the internal resistance increases, and the discharge performance rapidly increases. Leading to a decline. On the other hand, considering the variation of the electrode plate thickness and the workability when inserting the electrode plate group into the battery case, it is not appropriate to make it larger than 60 kg / dm ² . Further, if such a large repulsive force is given, when heat is generated during use, there is a risk that the battery case may be deformed even if the battery case wall thickness is increased. That is, the repulsive force of the separator when inserting the electrode group into the battery case is 20 to 60 kg / dm ²
It is preferable that In the above embodiment, the fiber diameter is about 2μ.
m glass fiber as the main component, thickness 1.0 mm, density 0.
A 16 g / cm ³ separator was used, but this tendency is
It was confirmed to be constant regardless of the density of the separator.

[Embodiment 3] Next, in a sealed lead-acid battery having the same structure as the battery of Embodiment 1-1, the repulsive force in the cells of the separator after formation of the battery case is 45 kg / dm.
² , lead-acid batteries were prepared in which the amount of the residual electrolyte solution was changed with respect to the theoretical void volume of the separator after the formation of the battery case, and the trickle life of them was measured. However, the measurement conditions and the judgment of the life were the same as in Example 2. The result is shown in FIG.
As shown in FIG. 5, when the residual amount of the electrolytic solution was 85% or less with respect to the theoretical void volume of the separator, the life was rapidly reduced as in the case of the liquid depletion phenomenon. In addition, the residual liquid amount is 98
%, The life was suddenly shortened. this is,
It is probable that the gas absorption capacity of the negative electrode plate decreased and the charging current increased, resulting in greater corrosion of the positive electrode grid.

Although sodium silicate is adhered to the positive and negative bipolar plates in each of the above embodiments, the same effect can be obtained by adhering it to at least one of the positive and negative electrodes. Further, although sodium silicate was attached to the surface of the paste paper by coating, the same effect can be obtained by spraying the solution onto the paste paper to attach it, or impregnating the paste paper in the solution in advance and attaching it. it can. Further, by using the expanded electrode plate grid, the electrode plate can be made thinner and the high rate discharge performance of the battery can be improved.

[0020]

According to the present invention, the electrode plate and the separator can be always brought into close contact with each other, and the high rate discharge characteristics and the trickle life of the sealed lead acid battery can be improved.

[Brief description of drawings]

FIG. 1 is a perspective view in which a part of a battery according to an embodiment of the present invention is cut away.

FIG. 2 is a characteristic diagram showing a trickle life of a battery according to an example of the present invention.

FIG. 3 is a characteristic diagram showing a weight reduction of an electrolytic solution in the same trickle life test.

FIG. 4 is a characteristic diagram showing a trickle life with respect to a compression ratio of the separator.

FIG. 5 is a characteristic diagram showing a trickle life with respect to a residual liquid amount of the same electrolytic solution.

[Explanation of symbols]

 1 Positive Plate 2 Separator 3 Negative Plate 4 Cell-to-Cell Connector 5 Battery Case 6 Lid

Claims (6)

[Claims] 1. A method for producing a sealed lead-acid battery, which comprises a step of attaching a paste paper to which an aqueous solution of sodium silicate is attached to a positive electrode plate or a negative electrode plate, and a step of aging and drying the positive electrode plate or the negative electrode plate. 2. A step of inserting an electrode group including a positive electrode plate, a negative electrode plate and a separator mainly composed of glass fiber into a polypropylene battery case having a thickness of 2 mm or more at a portion in contact with outside air. 1. The method for manufacturing the sealed lead storage battery according to 1. 3. The method for producing a sealed lead-acid battery according to claim 1, wherein the grids of the positive electrode plate and the negative electrode plate are expanded. 4. A repulsive force of the separator in a dry state in which an electrode group including a positive electrode plate, a negative electrode plate, and a separator mainly composed of glass fiber is inserted into a battery case and has a repulsive force of 20 to 60 kg /.
The method for producing a sealed lead acid battery according to claim 1, further comprising the step of inserting the battery into the battery case so as to have a dm ² . 5. The method for manufacturing a sealed lead-acid battery according to claim 1, wherein the paste paper is mainly composed of natural cellulose. 6. A step of further injecting a dilute sulfuric acid electrolytic solution into the battery cell to perform chemical conversion, and adjusting the amount of the remaining electrolytic solution so as to correspond to 85 to 95% of the theoretical void volume of the separator. The method for producing a sealed lead-acid battery according to claim 4, which comprises.