JPH04328271A - Sealed type lead-acid battery - Google Patents

Abstract

PURPOSE:To prevent movement of the powder material from the surroundings of poles to prevent lowering of battery performance by inserting current outputting poles through rings made of synthetic resin so as to contact close, and locating the rings so as to press a foam resin plate. CONSTITUTION:A foam resin plate 10 for fixing the powder material 3, which is filled in a battery jar 1 tightly, has acid resistance and the continuous foam, which passes electrolyte and gas but not the powder material 3, and when the pressure more than a constant pressure is applied to the plate 10, the plate 10 is deformed and not returned to the original shape. This plate 10 at an area larger than that of the battery jar 1 is pressed from the upper of the battery jar 1 to be inserted into the battery jar 1, inserting current outputting poles 6, 7 forcedly through the plate 10, and the plate 10 is made to contact close to the top surface of the powder material 3. At this stage, the poles 6, 7 are closely inserted through rings 9 made of synthetic resin, and the rings 9 are pressed to the plate 10 for location. The poles 6, 7 and the plate 10 are thereby made to contact close through the rings 9 to prevent blow-up of the powder material 3.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to improvements in sealed lead-acid batteries.

0002

BACKGROUND OF THE INVENTION There are two types of sealed lead-acid batteries in which the negative electrode absorbs oxygen gas generated during charging of the battery: a retainer type and a gel type. In the retainer type, a matte separator (glass separator) mainly made of fine glass fibers is inserted between the positive and negative electrode plates, and this holds the sulfuric acid electrolyte necessary for discharge and isolates the two electrodes. In recent years, it has been widely used as a backup power source for portable devices and computers due to its characteristics such as no maintenance, no leakage, and no position.

[0003] However, glass separators are made of fine glass fibers with a diameter of around 1 micron manufactured using a special method into a mat shape, and are considerably more expensive than separators for lead-acid batteries that are generally used. In addition, in order to obtain stable battery performance, the electrode plates must be strongly compressed and assembled, which makes assembly of the battery difficult and inevitably increases the manufacturing cost of the battery.

[0004] Furthermore, only the glass separator inserted between the positive and negative electrode plates can hold the sulfuric acid electrolyte, and the electrolyte cannot be kept around the electrode plates as in an open type lead-acid battery. Since the battery cannot be placed anywhere in the battery, the battery reaction is limited by the amount of electrolyte, which has the disadvantage that the battery performance is inferior to that of a liquid type battery.

On the other hand, gel type batteries are cheaper than cage type batteries, but their battery performance is inferior to that of cage type sealed lead acid batteries.
The drawback was that the electrolyte separated from the sulfuric acid gel during use, resulting in poor longevity.

[0006] In order to eliminate these drawbacks, sealed lead-acid batteries have been proposed that are neither retainer type batteries using fine glass fiber nor gel type batteries using a gel electrolyte. That is, a powder having high porosity and a large specific surface area, such as silica powder, is used as an electrolyte holding material, and the above powder is filled in the gap between the positive electrode plate and the negative electrode plate and around the electrode plate group. This is a sealed lead-acid battery.

[0007] Silica powder is an inexpensive material that is produced and sold in large quantities, and has excellent acid resistance and electrolyte retention ability, so it is a powder used as an electrolyte retaining material for this type of sealed lead-acid battery. It can be said that it is an excellent material. but,
In sealed lead-acid batteries that use this powder as an electrolyte holder, this powder moves to the top of the battery along with the electrolyte and gas generated from the electrode plates during charging, and is deposited between the positive and negative plates. It has been found that voids may occur, which may reduce battery performance.

Therefore, in order to suppress the movement of the powder, a porous thin sheet is placed on top of the powder, and a perforated resin plate with a plurality of holes is then forcibly inserted into the battery case. ,
Alternatively, foam the phenolic resin on top of the powder,
The silica powder was fixed. However, the method of using a thin porous sheet and a perforated resin plate in combination is complicated, and has the disadvantage that the perforated resin plate requires high dimensional accuracy because it is forced into the battery case.

On the other hand, the inside of foamed phenolic resin has open cells and has high porosity and excellent acid resistance, but a film called a skin layer is formed on the surface of foamed phenolic resin, which inhibits the permeation of gas and liquid. Therefore, it was necessary to devise a way to break this skin layer.

[0010] Therefore, a method was found for fixing the powder by pressing a foamed resin plate larger than the top surface of the battery case and having open cells from the top surface of the battery case and inserting it into the battery case. This method has a simple structure, good workability, and can solve the drawbacks of the above two methods. However, a new problem has emerged.

[0011] That is, when the foamed resin plate is pressed from the top surface of the battery case and inserted into the battery case, a gap may be created around the current extraction pole, and powder may blow through this gap while the battery is being charged. It was found that a void may be formed between the positive electrode plate and the negative electrode plate, and sufficient performance may not be obtained. This is caused by a slight misalignment when inserting the electrode plate group into the battery case, a slight misalignment of the pole in the vertical direction, and also due to misalignment when inserting the foamed resin plate into the battery case. It is extremely difficult to correct this deviation during the manufacturing process.

0012

[Means for Solving the Problems] The present invention fills the gap between the positive electrode plate and the negative electrode plate and the periphery of the electrode plate group with powder having high porosity and a large specific surface area, which is larger than the top surface of the battery case.
A foamed resin plate with open cells is pressed from the top of the battery case and inserted into the battery case to fix the powder, and a sufficient amount of sulfuric acid electrolyte is applied to substantially the powder. The problem with sealed lead-acid batteries that are impregnated in the body is to prevent powder from moving through the gaps that occur around the poles mentioned above. It is characterized by being inserted and pressed against a foamed resin board.

[0013]

EXAMPLES The present invention will be explained below based on examples. FIG. 1 is a cross-sectional view of the main parts of a sealed lead-acid battery according to the present invention.A battery case 1 includes a battery pack 2 consisting of a positive electrode plate, a negative electrode plate, and a ribbed separator for keeping the distance between the electrode plates constant. It is buried in 3. This electrode plate group is embedded in powder 3 to such an extent that its positive and negative electrode straps 4 and 5 are just hidden, and the powder 3 densely fills the area between the positive and negative electrode plates and around the electrode plate group 2.

The powder used here may be any powder having high porosity and large specific surface area, such as white carbon (fine powder of hydrated silicon dioxide), diatomaceous earth, fluorite (silica-rich calcium silicate powder), etc. ), all of which have a porosity of 80-90% and a specific surface area of 10-30%.
It is in the range of 0 m2 /g, and 1 of the glass separator
It has a considerably larger specific surface area compared to ~2 m2/g. Current extraction poles 6 and 7 are placed above the positive and negative electrode straps 4 and 5 of the electrode plate group embedded in the powder 3.
is formed.

Reference numeral 10 denotes a foamed resin plate having open cells for fixing the powder 3 densely packed in the battery case 1, and prevents movement of the powder 3 by the electrolytic solution and generated gas discharged from the electrode plate during charging. It has the role of preventing

This foamed resin board 10 not only has acid resistance, but also has open cells that allow the electrolyte and gas to pass through but not the powder 3, and when pressed at a certain pressure or higher, It has the property of being deformed and almost never returning to its original state. In this example, foamed phenolic resin was used.

This foamed resin plate 10 is larger than the top surface of the battery case 1, and is inserted into the battery case 1 by pressing it from above and inserting the current extraction poles 6 and 7 into contact with the inner wall of the battery case 1. It is inserted without any gap between the powders 3 until it comes into close contact with the upper surface of the powder 3. At this time, the inner wall of the battery case 1 and the foamed resin board 1
0 means that the foamed resin plate 10 larger than the top surface of the battery case 1 is pressed and inserted, so the foamed resin plate 10 is deformed and brought into close contact with the current extraction poles 6 and 7 and the foamed resin plate 10. There may be a gap between them.

For example, when the current extraction pole 6 (7) is not formed vertically as shown in FIG. occurs. If a gap 12 is created between the foamed resin plate 1 and the current extraction pole 6 (7) in this way, the electrolyte and generated gas discharged during charging will cause the powder 3 to fall between the foamed resin plate 10 and the current extraction pole. 6 (7), and a gap is created between the positive electrode plate and the negative electrode plate, resulting in insufficient performance.

However, in this embodiment, a ring 9 made of synthetic resin having a shape as shown in FIG. 2(A) is inserted closely through the current extraction poles 6 and 7. The foamed resin plate 10 and the current extraction pole 6 shown in
(7) Even if there is a gap 12 between the synthetic resin ring 9 and the foamed resin plate 10, the current extraction poles 6 and 7 and the foamed resin plate 10 can be connected to the synthetic resin by pressing the ring 9 against the foamed resin plate 10. The powder 3 can be brought into close contact with the powder 3 through a ring 9 made of aluminum, and the powder 3 can be prevented from blowing up. In the figure, 8 is an exhaust valve, and 11 is a lid of the battery case.

[0020] Then, the nominal capacity according to the present invention is about 30Ah.
We assembled a sealed lead-acid battery and investigated its effectiveness in preventing powder from blowing up. For comparison, a conventional battery was also tested in which the powder was fixed by pressing a foamed phenolic resin plate larger than the top surface of the battery case. In the test, the battery was first charged with a current of 10 A to see the effect of preventing the powder from blowing up, and then subjected to 5-hour rate discharge and low-temperature high-rate discharge. A battery charged with a small current of 2A was also added to the conventional battery.

[0021] When assembling the batteries, the steps up to filling the batteries with powder are performed using parts from the same lot, and then 30 batteries each are selected at random and the batteries are assembled into the above three types. Ta. The results are shown in Table 1. In Table 1, the numbers in parentheses are test results for batteries in which powder was blown up.

[0022]

[Table 1]

In conventional battery A, which was charged at 2A, there were 5 batteries in which powder was blown up, and in battery B, which was charged at 10A, powder was blown up in 18 batteries. This powder was blown up from between the current extraction pole and the foamed resin board, and it started to be blown up immediately after gas generation became active during charging. In conventional battery A, which was charged at 2A, the degree of gas generation was gradual, so powder was blown up in only 5 batteries, and the amount of powder blown up was small, but when charged at 2A, the amount of powder blown up was small. In conventional battery B, which was charged with 18 batteries, powder was blown up, and in some cases there was so much powder that it clogged the exhaust valve.

[0024] Table 1 shows separately the batteries in which the powder was blown up and the batteries in which the powder was not blown out, and the capacity of the battery in which the powder was blown up was significantly lower than that of the battery in which the powder was not blown out. There was a tendency that the larger the amount of powder blown out, the greater the decrease in capacity. On the other hand, in the batteries C of the present invention, there were no batteries in which the powder was blown up, and all of them had excellent discharge performance.

In the sealed lead-acid battery of the present invention, a synthetic resin ring having a shape as shown in FIG. 2(A) was used.
Rings having shapes as shown in (B) and (C) may also be used. Any shape may be used as long as it can sufficiently fill the gap created between the current extraction pole and the foamed resin plate.

Further, in this embodiment, the synthetic resin ring was pressed and embedded in the foamed resin plate, but it is not necessarily necessary to embed it. The synthetic resin ring may be pressed to the extent that the gap created between the current extraction pole and the foamed resin plate can be sufficiently filled.

[0027]

Effects of the Invention As explained above, the sealed lead-acid battery according to the present invention can be installed by simply inserting the synthetic resin ring closely into the pole and pressing the foamed resin plate. and prevents powder from blowing up during charging of a sealed lead-acid battery, which is densely packed around the electrode plate group so that the powder substantially retains a sufficient amount of electrolyte necessary for charging. It is possible to provide a battery that is capable of discharging and has an excellent discharge capacity, and is of great industrial value.

[Brief explanation of drawings]

[Fig. 1] Cross-sectional view of essential parts of a sealed lead-acid battery according to the present invention

[Figure 2] Diagram showing the state in which a synthetic resin ring is installed

[Figure 3
】Explanatory diagram showing the problems of conventional batteries

[Explanation of symbols]

1 Battery case 2 Pole group 3 Powder 6 Paul 7 Paul 9 Ring 10 Foamed resin board 11 Lid 12 Gap

Claims (1)

[Claims] Claim 1: Filling the gap between the positive electrode plate and the negative electrode plate and around the electrode plate group with powder having high porosity and large specific surface area, and forming a foamed resin plate larger than the top surface of the battery case and having open cells. The sealed lead is pressed from the top of the battery case and inserted into the battery case to fix the powder, and the powder is substantially impregnated with a sufficient amount of sulfuric acid electrolyte necessary for charging and discharging the battery. 1. A sealed lead-acid battery, characterized in that a ring made of synthetic resin is closely inserted into a current extraction pole and pressed against the foamed resin plate.