JPH05121059A - Paper type separator for lead-acid battery, its manufacture and the same battery - Google Patents

Abstract

PURPOSE:To lessen the internal resistance of a lead-acid battery and also to keep its discharge capacity at a high value by giving excellent adhesion to an electrode, and also always and quickly supplying the contained electrolyte to a face closely adhering to the electrode. CONSTITUTION:Inorganic powder of a specific surface area of not less than 100m<2>/gr, having about 2 to about 10% of an electrolyte contained therein, is included in a paper type separator consisting mainly of glass fiber at the rate of high filling density on one side-face thereof in the direction of its thickness but also at the rate of low filling density on the other side-face thereof.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a papermaking separator for a lead storage battery, a manufacturing method thereof and a lead storage battery.

[0002]

2. Description of the Related Art Conventionally, as a papermaking separator for a lead storage battery, only fine glass fibers having an average fiber diameter of 0.5 to 10 μm, or 1 to 1 of inorganic powder having a specific surface area of 100 m ² / g or more are used. A paper-making separator composed only of the glass fiber, which is obtained by wet-making a mixture of 40% by weight, and a paper-making separator in which the inorganic powder is uniformly mixed with a glass fiber sheet are known.

[0003]

The conventional separator made of only glass fiber has a large force for holding the electrolytic solution therein and is excellent in evenly holding the electrolytic solution. On the other hand, the surface of the separator is Is not smooth and has poor adhesion to the electrode plate surface, resulting in an insufficient amount of electrolyte solution at the interface with the electrode plate surface, especially when the electrolyte solution decreases over time during use of the lead acid battery. The supply amount to the surface is insufficient, and the electrolytic solution is not sufficiently supplied to the contact interface with the electrode plate, resulting in a rapid decrease in the battery discharge capacity. Further, it has recently been found that when the average fiber diameter is as thin as about 1 μm, the surface becomes hard, the adhesion to the electrode plate is further impaired, and the initial performance of the battery deteriorates. On the other hand, in the case of a paper-making separator in which inorganic powder is uniformly mixed, the surface becomes smooth and the adhesion with the electrode plate becomes good, but on the other hand, especially when the content of the inorganic powder increases. However, it has been found that the amount of the electrolyte retained therein is insufficient, the performance of moving and supplying the electrolyte to the surface is deteriorated, and the battery discharge capacity characteristics tend to be deteriorated. Therefore, it is desirable to provide a papermaking separator that solves the above problems of the conventional separators and that the lead storage battery has good initial performance and can maintain a high discharge capacity over time.

[0004]

DISCLOSURE OF THE INVENTION The present invention solves the above problems and provides a lead-acid battery papermaking separator that satisfies the above-mentioned needs, and is a papermaking process mainly composed of glass fibers having a fine fiber diameter. About 2 to 10 on the separator sheet
The inorganic powder having a specific surface area of 100 m ² / g or more, which is contained by weight%, has a high packing density on one side surface side in the thickness direction of the sheet.
Other side surfaces are mixed with a low packing density.

[0005]

The above-mentioned lead-acid battery separator has improved adhesion to the electrode plate surfaces when the high packing density side surface of the inorganic powder is used in contact with the anode plate and the cathode plate.
The initial capacity of the battery is improved, and the electrolytic solution contained and retained in the separator is retained in a large amount on the low packing density side of the inorganic powder, and is easy to move and supply toward the high packing density side. Fills the interface with the plate surface. As a result, the initial capacity of the battery is large, and even if the electrolytic solution decreases over time due to its use, it is possible to prevent the discharge capacity of the battery from decreasing and maintain the discharge capacity high. That is, the separator of the present invention is a lead-acid battery comprising an electrode plate group configured by abutting the high packing density packed side surface of the inorganic powder on the cathode plate surface and the anode plate surface, respectively, It is possible to obtain a battery having an excellent battery capacity. The above-mentioned separator of the present invention is mainly composed of acid resistant glass fibers having an average fiber diameter of 0.5 to 10 μm, and about 2 to 10% by weight of acid resistant inorganic powder having a specific surface area of 100 to 400 m ² / g. When adding and mixing without adding a binder and making the mixture into a paper, the paper web is subjected to suction dehydration treatment by suction, and the inorganic powder is sucked up to one side of the paper web to obtain 1 in the thickness direction. By allowing the side surface side to have a high packing density and the other side surface side to have a low packing density, the lead acid battery separator of the present invention having the above-described actions and effects can be manufactured.

[0006]

EXAMPLES Next, examples of the present invention will be described in detail. The acid-resistant glass fiber generally has an average fiber diameter of about 0.5 to 10 μm.
Use a fine fiber diameter selected from the range. For example, acid resistant glass fibers obtained by melting and spinning C glass are preferable. 90 to 98% of the acid resistant glass fibers and an acid resistant inorganic powder having a fine particle size selected from a specific surface area of 100 to 400 m ² / g are mixed in water by stirring in an amount of about 2 to 10%. As such an acid resistant inorganic powder, solid fine powder such as talc silica or silicon dioxide may be used, but colloidal silica such as Aerosil is preferable. in this case,
Without using a binder for adhering the inorganic particles to the glass fiber, for example, in order to uniformly and cohesively adhere the colloidal silica to the glass fiber, a cationic polymer flocculant, for example, a cationic copolymer containing an acrylamide group. Ethyleneimine 0.1% concentration solution, the total solid content of 0.
1-0.5% is gradually added to the above mixture. The mixed papermaking raw material thus prepared is made into a papermaking machine using a general paper machine such as a round net, a shortnet, and a fourdrinier, and the suction force is applied when the web is sucked and dehydrated by a suction box, a couch roll, etc. Is made particularly large so that a part of the inorganic powder mixed in the paper web is sucked and biased toward the paper making side. Next, such wet papermaking is heated and dried to obtain the papermaking separator of the present invention. Thus, in the separator of the present invention, about 2 to 10% of the acid-resistant glass fiber sheet contains silica powder having a high packing density on one side in the thickness direction of the sheet and a low packing density on the other side. In addition, it can be obtained as a papermaking separator for a lead storage battery in which the packing density of the inorganic powder is different in the thickness direction. In this way, the acid-resistant glass fiber is mainly used, and the packing density of the inorganic powder in the case of uniformly adding a predetermined amount of the inorganic powder to this is a uniform packing density over the whole, In the invention, one side surface side having a higher packing density than the uniform packing density by suction is referred to as a high packing density side, and the other side surface having a smaller packing density than the uniform packing density is referred to as a low packing density side.

The reason why the inorganic powder is limited to those having a specific surface area of 100 m ² / g or more is that when the particles are 100 m ² / g or less, the particles are coarse and the suction movement becomes difficult, and the surface of the papermaking separator is difficult. No smoothness was obtained, and the battery capacity was greatly reduced with a decrease in the electrolytic solution, and the filling effect was not obtained. Also, the addition amount of the inorganic powder is about 2 to 10%.
The reason for this is that, as will be described later, a high filling density effect cannot be obtained at about 1%, and if 12% or more, the filling amount becomes excessive as described later, and the electrolyte holding amount decreases and the In this case, the supply rate of the electrolytic solution becomes slower, and the discharge capacity is greatly reduced with the use of the battery. From the viewpoint of electric resistance, addition of 15% or more is not preferable because it increases electric resistance.

In the papermaking separator of the present invention thus obtained, since the packing density of the inorganic powder is made different in the thickness direction as described above within the range of the above-mentioned addition amount, on the high packing density side. The adhesiveness with the electrode plate surface is improved, the electrolyte holding property on the low packing density side is excellent, and the feeding speed of the electrolyte solution on the high packing density side is fast, so that the feeding performance is excellent.

Since the papermaking separator of the present invention has the above-mentioned constitution, it is preferable to use it so that the smooth surface on the high packing density side is always in contact with the electrode plate. That is, one of the sheets is folded in two with the high packing density side surface outside or inside, and the high packing density side surface is brought into contact with the electrode plate surface of the cathode plate or the anode plate, or the two sheets are used. The low packing density side faces are laminated back to back, and the laminated separator is used so as to be interposed between the cathode plate and the anode plate. The thus constructed electrode plate group is incorporated into a battery container to obtain the lead storage battery of the present invention. Thus, the initial capacity of the lead storage battery is large, and even if the electrolyte solution decreases due to its use, the electrolyte solution retained inside the low packing density side, that is, in the coarse porous structure is the high packing density side. Is easily and quickly supplied by capillary action easily and quickly, and since the interface between the high packing density side surface and the electrode plate surface can be always filled with the electrolytic solution,
The decrease in battery discharge capacity is small, high discharge capacity can be maintained, and the service life can be increased.

Next, a comparative test in which the content of the inorganic powder is changed will be described. Using glass fibers having an average fiber diameter of 1 μm and silica powder having a specific surface area of 200 m ² / g as raw materials,
98%, 95%, 90% of the glass fiber and the silica powder 2
%, 6% and 10% were added to water with different blending ratios, stirred and mixed to dissociate, and a cationic polymer flocculant having a concentration of 0.1% was added to the mixed solution at 0.2% of the total solid content. % Is gradually added, and the mixture is applied to a tilted short-net paper machine to form a web, and in the process of transferring this with a net, the suction couch roll raises the vacuum degree significantly higher than the vacuum degree for normal suction dehydration. At the same time as dewatering by the large suction force, the inorganic powder uniformly mixed in the paper web is sucked and biased toward the mesh surface side, and then the paper web is heated and dried by a dryer to carry out the present invention shown in Table 1 below. Separator sample NO. 1, NO.
2, NO. 3 and NO. The paper-made separators of the present invention having different packing densities of the inorganic powders in the respective thickness halves in the thickness direction were manufactured.

For comparison, the compounding ratio of the glass fiber and the silica powder different from those in the above-mentioned examples, that is, 99%, 88%, 85% of glass fiber and 1%, 12% of silica powder,
Comparative separator sample N in Table 1 below was prepared by papermaking in the same manner as in the above example, except that the mixture ratio was 15%.
O. 1, NO. 2 and NO. The comparative papermaking separator shown in 3 was manufactured.

Separately from the above, a conventional papermaking method is used to make only the above-mentioned glass fibers as a raw material, and the paper web is sucked and dehydrated by a couch roll having a normal vacuum degree. ． The conventional papermaking separator shown in 1 was manufactured. Further, the above glass fiber 9
5% and 5% of the silica powder described above were used to make paper in the same manner as described above, and the paper was subjected to suction dehydration with a couch roll having a normal degree of vacuum. Conventional separator sample NO. A conventional papermaking separator shown in 2 was manufactured. Incidentally, these conventional separator sample Nos. 1 and N
O. No. 2 was manufactured to the same thickness as the papermaking separator of the present invention.

[0013]

[Table 1]

In Table 1, the packing density is 1 when the inorganic powder is uniformly packed in the papermaking separator, and the packing density of one side half and the other side half in the thickness direction. Was represented.

Inventive separator sample N shown in Table 1
O. 1-NO. 4 and comparative separator sample NO. 1
~ NO. Two pieces each having a predetermined size of 3 were used, and the low packing density side surfaces of which were superposed back to back were inserted between the cathode plate and the anode plate, and the high packing density side surfaces were contacted with the cathode plate and the anode plate surface. A group of electrode plates in contact with each other is formed, and this group of electrode plates is incorporated into a monoblock battery case, and the lead storage battery sample NO. 1, NO. 2, NO. 3, NO. 4 Lead acid battery sample No. 4 for comparison 1, NO. 2, NO. 3 was produced. Separately, the conventional separator sample NO. 1, NO. Two
No. 1 of the conventional lead storage battery sample No. 1 was prepared by stacking two sheets of the specified size of No. 1 and inserting each between the cathode plate and the anode plate to form a conventional electrode plate group, and incorporating this electrode plate group in the monoblock battery case. 1, NO. 2 was produced. In this case, regarding each of the lead-acid battery samples described above, assuming that a sulfuric acid electrolytic solution having a specific gravity of 1.32 was injected in a saturated amount and a battery in which the electrolyte was reduced due to long-term use, the saturation amount was 95%, %, And three types of batteries having different amounts of electrolyte were prepared. For these batteries, the battery capacity and the internal electrical resistance were tested according to JIS C8702. The measurement results are shown in Table 2.

[0016]

[Table 2]

Furthermore, in order to study the influence of the particle size of the inorganic powder, silica powder having a specific surface area of less than 100 m ² / g,
That is, for example, 5% of silica powder having a specific surface area of 90 m ² / g
Except that the glass fiber was mixed with 98% of the above glass fiber, the sample NO. In the same manner as in No. 2, the comparative separator sample No. The comparative papermaking separator shown in FIG. 4 was produced and two sheets of the separator were used. An electrode plate group was constructed in the same manner as in No. 2, and using this, the comparative battery sample NO. No. 4 lead-acid battery was manufactured, and the electrolyte was injected with a saturated amount of 95% and 90%, respectively, and the electric resistance and the battery capacity were measured in the same manner as described above. The results are shown in Table 2. The separator sample NO. 2 and battery sample NO. Two
As is clear from comparison with, the specific surface area of the inorganic powder is 100
It has been confirmed that particles having a large m ² / g or less have a short adhesion because the adhesion to the electrode plate is poor, the electric resistance increases, and the battery capacity decreases rapidly due to the decrease in the electrolytic solution.

For comparison, one of the separators of the present invention whose thickness is doubled is inserted between a cathode plate and an anode plate to form an electrode plate group. The resistance and battery capacity were examined. That is, the separator sample NO. One electrode No. 2 is inserted between the cathode plate and the anode plate to form an electrode plate group, and using this, the comparative battery sample NO. The lead acid battery shown in FIG. 5 was manufactured, and the electric resistance and the battery capacity of the lead acid battery were measured, although the injection amount of the electrolytic solution was different from the saturation amount, 95% and 90%. The results are shown in Table 2, and the internal resistance of the battery increases,
This caused a sharp drop in battery capacity. It is considered that this is because the adhesion between the low packing density side surface of the separator and the electrode plate surface is poor.

For comparison, the separator sample NO. No. 2 of Comparative Battery Samples of Table 2 are formed by inserting two sheets of No. 2 having their high packing density side-to-side back to back between the cathode plate and the anode plate.
The lead storage battery shown in FIG. 6 was manufactured, and the internal resistance and the battery capacity of the same were measured in the same manner with the electrolyte injection amount saturated at 95% and 90%. The results are shown in Table 2.

As is clear from Tables 1 and 2, the fine glass fibers have a specific surface area of about 90 to 98% and a specific surface area of 100 m ² /
A papermaking machine in which about 2 to 10% of inorganic powder of g or more is mixed and made into a paper, and the packing density of the inorganic powder is one side having a high packing density and the other side having a low packing density in the thickness direction. When a formula type separator is manufactured and a plate group is provided so that its high packing density side faces contact the cathode plate and the anode plate and this is equipped in a lead acid battery, the internal resistance of the battery can be kept low and It is recognized that the initial capacity of the battery is improved and the discharge capacity of the battery can be maintained high even when the electrolyte solution is reduced. Such an improvement is to improve the adhesiveness between the separator and the electrode plates and to supply the electrolytic solution from the low packing density side to the high packing density side surface satisfactorily and promptly to keep the electrolytic solution at the interface with the electrode plate. It is thought to be due to the satisfaction.

[0021]

As described above, the papermaking separator of the present invention is mainly composed of glass fibers having a fine fiber diameter, and the glassmaking separator of about 2
An inorganic powder having a specific surface area of 100 m ² / g or more of 10%,
Since one side surface side in the thickness direction is mixed with high packing density and the other side surface is mixed with low packing density, the high packing density side surface is brought into contact with the cathode plate surface and the anode plate surface. When a lead-acid battery is manufactured using the electrode plate group, the internal resistance of the lead-acid battery decreases, and even when the electrolyte solution decreases due to its long-term use, the high discharge capacity is long-term. The effect that can be maintained is brought about. Thus, the paper-making separator that causes the density of such inorganic powder to be densely packed in the thickness direction uses the suction in the paper-making process and has an inorganic force larger than the suction force used in the conventional dehydration treatment. By exerting a suction force large enough to attract the powder to one side of the web, the web can be easily obtained.

Claims (3)

[Claims] 1. An inorganic powder having a specific surface area of 100 m ² / g or more, which is contained in about 2 to 10% by weight in a paper-making separator sheet mainly composed of glass fibers having a fine fiber diameter, in the thickness direction of the sheet. A papermaking separator for a lead storage battery in which one side has a high packing density and the other side has a low packing density. 2. A glass fiber having an average fiber diameter of 0.5 to 10 μm of about 98 to 90% and a specific surface area of 100 m ² / g to 400.
About 2 to 10 parts by weight of m ² / g of inorganic powder is added and mixed in water without adding a binder, the mixed solution is made into paper, and the paper web is subjected to suction dehydration treatment and the inorganic powder is mixed. Manufacture of a papermaking separator for a lead storage battery, which is characterized in that one side of the paper web is sucked up and one side in the thickness direction is mixed with a high packing density and the other side is mixed with a low packing density. Law. 3. The papermaking separator for a lead storage battery according to claim 1, comprising an electrode plate group constituted by contacting a high packing density side surface of the inorganic powder with a cathode plate surface and an anode plate surface. Lead acid battery.