JPH04349358A - Sealed-type lead acid battery - Google Patents

Abstract

PURPOSE:To prevent pulverulent body from moving toward the upper part of a battery through gaps formed around a pole and prevent the battery's function from lowering wherein the battery is a sealed-type leads-torage battery filled with the pulverulent body and whose electrolyte is substantially held in the pulverulent body by impregnating the pulverulent body with the electrolyte. CONSTITUTION:A sealed-type lead-storage battery has such a structure that a foam resin plate 6 including continuing bubbles is placed above pulverulent body and a gap 3 from the foam resin plate 6 and poles 4 to a battery case 1 is closed and hardened by resin.

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. Silica powder is an inexpensive material that is produced and sold in large quantities, and has excellent acid resistance and electrolyte retention ability, making it an excellent powder for use as an electrolyte retention material in this type of sealed lead-acid battery. It can be said that it is a material.

However, in a sealed lead-acid battery that uses this powder as an electrolyte holder, this powder moves to the top of the battery together with the electrolyte and generated gas discharged from the electrode plate during charging, and the positive and negative electrode plates move together. It has been found that voids may be formed between the battery and the plate, 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. It was necessary to find a way to break through the 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. In other words, when the foamed resin plate is pressed from the top of the battery case and inserted into the battery case, a gap may be created around the current extraction pole, and while the battery is being charged, powder may blow up from this gap and cause the positive electrode to It has been found that a gap may be formed between the plate and the negative electrode plate, and sufficient performance may not be obtained.

[0011] 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. also happens. 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 large specific surface area, thereby providing the necessary and sufficient powder for charging and discharging the battery. This is to prevent the powder from blowing up to the top of the battery, which is a problem with sealed lead-acid batteries in which the powder is substantially impregnated with a large amount of sulfuric acid electrolyte. A resin plate is placed on the foam resin plate, and the gap between the battery case and the pole is sealed with resin.

[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. The powder used here may be any powder with 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. Yes, both have a porosity of 80-90% and a specific surface area of 1
It has a specific surface area in the range of 0 to 300 m2/g, which is considerably larger than that of a glass separator, which has a specific surface area of 1 to 2 m2/g. This time, white carbon was used as the powder 3. A current extraction pole 4 is formed above the electrode plate group embedded in the powder 3. The foamed resin board 6 is fixed to the upper part of the powder by resin 7.

[0014] The foamed resin plate was fixed in the following manner. Figure 2 shows how it looks from above. First, a foamed resin plate smaller than the top of the battery case with a hole in the pole was placed on top of the powder. Epoxy resin was then poured into the gaps between the pole, battery case, and foam resin board, and allowed to harden.

The electrolytic solution can be injected through the foamed resin plate, and gas generated from the electrode group during charging can escape through the foamed resin plate. The powder is held down by a foamed resin plate, and the gaps are filled with resin, so the powder does not blow up.

Next, a sealed lead-acid battery according to the present invention with a nominal capacity of 30 Ah was assembled, and the effect of preventing powder from blowing up was investigated. Ten batteries were made, charged at a current of 10A for about 20 hours, and then discharged at a rate of 5 hours (25℃, 6 hours).
A) and low temperature high rate discharge (-15°C, 150A). The results are shown in Table 1.

[0017]

[Table 1]

[0018] In any of the batteries, no powder was observed to blow up inside the battery. and 5 hour rate capacity,
The high rate discharge capacity was also good with little variation.

Although epoxy resin was used as the resin this time, any resin can be used as long as it has acid resistance and good adhesion to the battery case and pole. For example, tests were also conducted using ultraviolet curing resin (epoxy acrylate type) as the resin. This is done by irradiating ultraviolet light,
It was possible to harden it in about 5 seconds. As in the case of epoxy resin, blowing up of the powder was prevented, and no problems were observed in the capacity test.

[0020]

[Effects of the Invention] As explained above, in the sealed lead-acid battery according to the present invention, a foamed resin board having open cells is placed on top of the powder, and the gaps between the battery case and the pole and the foamed resin board are solidified with resin. The problem with sealed lead-acid batteries is that the powder is densely packed around the positive and negative electrode plates and the electrode plate group, so that the powder substantially retains a sufficient amount of electrolyte necessary for charging. It is possible to prevent the powder from blowing up during charging, which was a problem, and to provide a battery having an excellent discharge capacity, which 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

FIG. 2 is a top view showing how the foamed resin board of the present invention is fixed.

[Explanation of symbols]

1 Battery case 2 Pole group 3 Powder 4 Paul 5 Lid 6. Foamed resin board 7 Resin

Claims (1)

[Claims] Claim 1: A powder having high porosity and a large specific surface area is filled in the gap between the positive electrode plate and the negative electrode plate and around the electrode plate group, and a sufficient amount of sulfuric acid electrolyte necessary for charging and discharging the battery is substantially filled. A sealed lead-acid battery is impregnated with the powder and a foamed resin plate having open cells is placed on top of the powder.
A sealed lead-acid battery characterized by the gap between the battery case, pole, and foamed resin board being filled with resin.