JPH06203822A - Manufacture of lead-acid battery separator - Google Patents

Abstract

PURPOSE:To prevent short circuits, particularly those occurring at the lower portion of a battery so as to prolong the life of the battery with quality stabilized by initially cutting the portion of a glass mat opposite to the legs of a pole plate, and bonding the glass mat to a separator base using an adhesive. CONSTITUTION:A glass mat 1 is bonded and integrated to a separator base 2 using an adhesive 4 and then cut to size to form a separator. In this case, a large-size mat 1 obtained by initially cutting the portion of the mat 1 used opposite to the legs of a pole plate is bonded to the base 2 by stripes of adhesive 4 applied to the base 2. The mat 1 is formed from glass fiber and the base 2 is wet formed from inorganic powders, inorganic fibers, organic fibers and a small quantity of binder. A lead-acid battery is formed using the separator thus manufactured, so as to prevent short circuits, particularly those occurring at the lower portion of the battery, so as to prolong the life of the battery with quality stabilized.

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art Lead acid batteries are currently used in various fields including automobiles and industrial applications.
Among them, automobile batteries are in great demand, and there is a demand for weight reduction, cost reduction, maintenance-free operation, longer life, and stable quality.

However, this automobile battery has many life modes, and in particular, a short circuit causes a short life, which results in a long life.
It is a big problem in terms of quality stabilization. Especially, a short circuit around the electrode plate, especially a short circuit at the lower part of the electrode plate is a problem.

This is because particles of lead dioxide, which is a positive electrode active material that has fallen off from the electrode plate due to repeated charging / discharging or vibration of a car, floats up due to convection of the electrolytic solution and accumulates on the legs of the negative electrode plate. It is considered that it is caused by growing as metallic lead by being reduced and coming into contact with the lower lattice part of the positive electrode plate.

At present, the separator mainly used in this type of lead-acid battery is one in which both sides of a glass mat and a separator substrate (for example, a paper product of inorganic powder and fibers) are bonded together. However, the above-described growth of metallic lead is particularly likely to occur in the gaps between the fibers in the glass mat. Therefore, this separator does not play a role in preventing the short circuit around the electrode plate.

Various methods have been proposed and various proposals have been made as a method for preventing a short circuit occurring around the electrode plate. Among them, many patents for devised separators have been filed and put into practical use.

One of them is one in which a negative electrode plate or a positive electrode plate is wrapped in a bag-shaped separator to prevent a short circuit,
Although it has already been put to practical use, in this method, the step of wrapping the electrode plate with the bag-shaped separator is difficult, and the electrode plate group is also manufactured by using the separator in which the glass mat and the separator substrate are bonded together. Much more difficult than Also,
The cost of the bag-shaped separator itself is higher than that of the separator in which the glass mat and the separator substrate are bonded together.

Regarding the separator in which the glass mat and the separator substrate are bonded together, in JP-A-58-129746, the lower part of the glass mat of the separator is removed, and the removed portion is made of the same material as the separator substrate and the same as the glass mat. It has been proposed that a lower short circuit is prevented by using a separator having a thickness attached. Further, it has been known that if the peripheral portion of the glass mat is made smaller than the separator substrate by several millimeters, a short circuit is less likely to occur in the peripheral portion of the electrode plate, and it has already been put to practical use in some lead-acid batteries for electric vehicles.

However, all of these methods have a problem that they are difficult to manufacture and costly.

Conventionally, this type of separator has been disclosed in Japanese Examined Patent Publication No. 55-13.
As shown in 379, the separator base and the glass mat are manufactured by adhering a large-sized separator base and a glass mat with a band-shaped adhesive to integrate them and then cutting them into a predetermined size. And had the same shape and dimensions. Therefore, the separator in which the peripheral portion of the glass mat is made smaller than the separator substrate by several millimeters as described above is manufactured by cutting and removing a part of the glass mat of the separator manufactured as described above.

[0011]

SUMMARY OF THE INVENTION The present invention solves the above problems and is a method for producing a lead storage battery separator in which a separator substrate and a glass mat are bonded together with an adhesive to be integrated and then cut into a predetermined size. In the above method, the glass mat of the portion of the lead storage battery electrode plate facing the foot is cut off in advance. As a result, the present invention provides a lead-acid battery in which a short-circuit, particularly a lower short-circuit is less likely to occur by using a separator that is easily and inexpensively manufactured.

[0012]

EXAMPLES The present invention will be described below based on examples.

FIG. 1 is a schematic view showing a method for manufacturing a separator for a lead storage battery according to the present invention, (A) is a schematic view of a large-sized glass mat 1 used in the present invention, and (B) is the glass mat 1 FIG. 3 is a schematic view showing a state in which is attached to a separator substrate 2. Reference numeral 3 denotes a cut-out portion of the glass mat 1, and as shown in FIG. 1 (A), a large-sized glass mat 1 in which a portion of the lead-acid battery electrode plate facing the foot is cut off in advance (B) As shown in (1), the separator substrate 2 having a large size is attached to the separator substrate 2 with the adhesive 4 applied in a strip shape to be integrated, and then cut into a predetermined size to form a separator. A schematic view of the separator after cutting is shown in FIG.

The glass mat 1 used here has a fiber diameter of 13
A micron glass fiber was made into paper, and a separator substrate 2 was wet paper made using inorganic powder, inorganic fiber, organic fiber and a small amount of binder.

Next, using the separator manufactured according to the present invention, an automobile lead storage battery (nominal capacity 28 Ah, 5 hour rate) having 4 positive electrode plates and 5 negative electrode plates per cell was prepared. Generally, there are two types of alloys for the positive electrode plate grid, a lead-calcium type alloy and a lead-antimony type alloy, but here, two types of batteries were prepared by using those having a normal composition.

FIG. 3 shows a structure of an electrode plate group of a lead acid battery for an automobile using the lead acid battery separator according to the present invention. Reference numeral 5 is a positive electrode plate, 6 is a negative electrode plate, and 7 is an electrode plate leg.

For comparison, a conventional separator having the same shape and size is used for the separator substrate and the glass mat, which are used in an ordinary lead acid battery, and the above-mentioned 2 is used.
Similar types of batteries were made. Table 1 shows the contents of these test batteries.

[0018]

[Table 1]

Battery No. Nos. 1 and 2 are batteries using the separator according to the present invention in which a part of the lower edge of the glass mat facing the foot of the electrode plate is cut off. Reference numerals 3 and 4 are batteries using a conventional separator in which the glass mat and the separator substrate have the same shape and size.

The results of subjecting these batteries to a JIS D5301 heavy load life test are shown in FIG. During the life test, the discharge was 20 A × 1 h, the charge was 5 A × 5 h, and the test temperature was 4
2.5 ± 2.5 ° C.

Battery No. 1 using a conventional separator and using a lead-calcium alloy for the positive electrode grid. No. 3 had a life of 70 cycles, whereas Battery No. 3 using the separator according to the present invention and using a lead-calcium alloy in the positive electrode grid.
No. 1 had a life of 170 cycles, which was more than twice as long as that of the battery using the conventional separator.

When the battery was disassembled in order to investigate the cause of life, the battery No. 1 using the conventional separator was used. No. 3 had a life due to a lower short circuit, but the battery No. No. 1 had a lifetime due to the softening of the active material and the formation of a so-called barrier layer in which the active material-lattice interface was discharged preferentially over the active material to form a passive layer, and a lower short circuit was hardly seen. .

Further, the battery No. 1 using a conventional separator and using a lead-antimony alloy for the positive electrode grid. No. 4 has a life of 330 cycles, whereas the battery No. 4 using the separator according to the present invention and using the lead-antimony alloy for the positive electrode grid. No. 2 has a life of 440 cycles, which is about 1.3 times as long as that of the conventional separator.

When the battery was disassembled in order to investigate the cause of life, the battery No. 1 using the conventional separator was used. No. 4 had a life due to a lower short circuit, but battery No. 4 using the separator according to the present invention. No. 2 had a life due to softening and falling off of the active material, and almost no lower short circuit was observed.

It should be noted that the cut portion of the glass mat is not necessarily required at all the portions facing the legs of the positive and negative electrode plates as shown in the embodiment, and is provided only at the lower edge portion facing the legs of the negative electrode plate. However, the effect is almost the same. In addition, the cutout may be provided in the upper part of the separator symmetrically with the lower part so that the separator does not interfere with the vertical direction when the battery is assembled.

Further, it goes without saying that there is no problem even if a roll-shaped separator substrate and / or a glass mat is applied to the production method of the present invention.

[0027]

As described above, when the lead-acid battery separator according to the present invention is used, it is possible to prevent the lead-acid battery from short-circuiting, especially lower-side short-circuiting, thereby improving the life performance and stabilizing the quality. In addition, the cost is lower than that of a conventional lead storage battery using a separator for preventing a lower short circuit, and its industrial value is enormous.

[Brief description of drawings]

FIG. 1 is a schematic view showing a method for producing a separator for a lead storage battery according to the present invention.

FIG. 2 is a schematic diagram showing the shape of the separator according to the present invention.

FIG. 3 is a schematic view showing a plate group using a separator according to the present invention.

FIG. 4 is a diagram showing the results of a heavy load life test.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Glass mat 2 Separator base material 3 Excision part 4 Adhesive 5 Positive electrode plate 6 Negative electrode plate 7 Electrode plate feet

Claims (1)

[Claims] 1. A method for manufacturing a lead-acid battery separator in which a separator substrate and a glass mat are bonded together by an adhesive to be integrated and then cut into a predetermined size, wherein a portion of the lead-acid battery electrode plate facing a foot is previously prepared. A method for manufacturing a lead-acid battery separator, which comprises cutting out a glass mat.