JPH07220706A - Lead-acid battery for automobile - Google Patents

Abstract

PURPOSE:To prevent an electrolyte from splashing and vaporizing through a porous material by providing the porous material inside a vent plug, and setting the ventilation resistance of the porous material to a predetermined value. CONSTITUTION:A vent plug main body has openings 2 provided through one side, and the ventilation resistance of a porous material 5 is in the range 30-300mm as measured by a water-column manometer when the quantity of air fed is 5l/min, i.e., a much smaller resistance than in conventional batteries is set. In this case, the porous material contains coarse particles 60% or more of which are 100mum in diameter and 10% or more of which are 300mum or larger in diameter, with the particles of different diameters intermingled, so that the ventilation resistance can be set to a desired value in the range from about 30 to 300mum. Therefore, a passage can be widened with the passage diameter kept very large, and so water vapor, i.e., steam (b) tends to adhere to the wall of the passage, particularly near the bottom surface of the passage, but most of the steam is forced back because of water repellent finish, while gas (a) is expelled out of the battery through the passage. A grating lead alloy with a calcium content of 0.08 to 0.09% is employed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to improvement and improvement of liquid reduction characteristics of lead acid batteries for automobiles.

[0002]

2. Description of the Related Art Lead acid batteries generate hydrogen gas and oxygen gas by electrolysis of an electrolyte at the end of charging. Therefore, a liquid mouth plug having a gas exhaust hole is used, and an explosion-proof filter material is used as necessary. This explosion-proof filter usually uses a porous body having a relatively high ventilation resistance in order to prevent ignition into the cell. On the other hand, the most important maintenance for lead-acid batteries is water replenishment work, but the main cause of the decrease in electrolyte is the electrolysis of water due to the difference in charging voltage due to the lead alloy used for the grid, and the generated gas is the exhaust port of the liquid spout. This is because it is more discharged. In the past, the liquid reduction performance was improved by studying and adopting an alloy with a high battery voltage that causes electrolysis in the grid. Specifically, a low-antimony alloy with a reduced antimony content, which reduces the gas generation voltage at which gas begins to be generated, and a maintenance-free type with a small amount of liquid reduction have been devised and realized by using a calcium alloy in the lattice. ing.

Another factor that causes a decrease in the electrolytic solution is that the evaporated portion of the electrolytic solution due to the temperature rise also passes through the liquid spout, but the amount thereof is smaller than that by electrolysis. is there.

[0004]

However, due to recent changes in the market traffic environment such as four-wheel drive and high temperature in the engine room, along with the improvement of the automobile itself, vibration resistance of lead-acid batteries is also expected. Properties and high temperature resistance have come to be required.

A battery using a calcium alloy, which is maintenance-free and eliminates the rehydration work associated with liquid reduction,
Even in the practical test of the battery using the liquid mouth plug that adopts the maze structure, there is a large amount of electrolyte that evaporates due to the loss of the electrolyte through the liquid mouth plug and the temperature rise, and there are some that can not fully demonstrate the liquid reduction performance. there were.

Further, even if a liquid port plug having a filter is used, overflow problems may similarly occur continuously under relatively high vibration conditions found in recent four-wheel drive vehicles and the like.
This is because the pore size of the filter designed with priority on explosion proof is distributed in a relatively small one, and although the droplet electrolyte is once attached to the filter, it is refluxed into the electrolyte due to the water repellency of the filter itself. This is because the gas exhaust path and the portion where the droplet electrolyte is adhered are in the same portion, and due to expansion of the space inside the battery due to temperature rise and the like, the gas is discharged through the filter and continuously overflows. In such a maintenance-free battery, a decrease in the electrolytic solution may occur.

[0007]

DISCLOSURE OF THE INVENTION The present invention relates to a lead-acid battery using an electrode plate grid made of a calcium alloy, and a water column manometer at an air blowing rate of 5 l / min in the middle of a gas exhaust path of a liquid port plug. A liquid mouth plug equipped with a porous body having a numerical value in the range of 30 mm or more and 300 mm or less is provided, and 60% or more of the coarse particles as a raw material of the porous material have a diameter of 100 μm or more. Also, 10% or more of particles having a diameter of 300 μm or more are mixed, the pore size near the surface of the porous molded product is smaller than that inside the molded product, and the water repellency is closer to the surface than the inside of the porous molded product. It has a structure in which many agents are unevenly distributed.

[0008]

[Function] In order to minimize the decrease of the electrolytic solution, the electrode plate group structure which suppresses the electrolysis at the time of charging by the electrode plate grid made of calcium alloy and minimizes the decrease of the electrolytic solution amount is used. At the same time, it is necessary to prevent the loss due to evaporation of the electrolytic solution at high temperature due to the film formed by the splash of the electrolytic solution. That is, microvibration including normal traveling vibration has the function of promoting evaporation of water and generation of atomized electrolyte, and considering the replacement of gas inside and outside the battery, vertical vibration Acts on gas replacement. Further, in the high vibration region, gas replacement can suppress the overflow phenomenon at the time of gas exhaust by the splash-proof structure of the liquid spout itself. In the present invention, by setting the ventilation resistance condition of the porous body of the filter attached to the liquid mouth plug, scattering and evaporation of the electrolytic solution through the filter are prevented.

[0009]

EXAMPLES Examples according to the present invention will be described below.

FIG. 1 shows the cross-sectional state of the liquid mouth plug of the present invention.
FIG. 2 shows a conventional liquid stopper for comparison.

2A shows the case where the explosion-proof filter is not attached, and FIG. 2B shows the case where the filter is attached. Further, in FIG. 1 and FIG. 2, reference numerals 1 and 2 are the inlets of the exhaust gas, and the conventional liquid spout has an opening at the bottom surface of the spigot body, whereas in the present invention, it is located laterally of the spout body. An opening is provided in the section. As for the ventilation resistance of the conventional explosion-proof filter 6 of the liquid mouth plug of FIG. 2B, a porous body is used so that the numerical value of the underwater manometer is about 300 to 400 mm when the air blowing rate is 5 l / min. On the other hand, the ventilation resistance value of the porous body 5 of the present invention is in the range of 30 to 300 mm in terms of manometer value, and it is a porous body having a resistance value extremely smaller than the conventional one. A schematic diagram for making this difference easy to understand is shown in FIG. FIG. 3A is an enlarged partial sectional view of the porous body of the present invention, and FIG. 3B is an enlarged partial sectional view of a conventional explosion-proof filter. For the explosion-proof filter, a sintered body of alumina oxide was used as the material for both the porous body of the present invention and the conventional example.

The porous material of the present invention has a coarse particle diameter of 100.
It is possible to adjust the ventilation resistance value to an arbitrary value within the range of about 30 to 300 mm by making 60% or more of μm or more and 10% or more of those of 300 μm or more mixed. As a result, as compared with the conventional explosion-proof filter of B, it becomes possible to hold the passage diameter in an extremely wide width. By widening the passages in this way, the vaporized substance of water, that is, the water vapor (b) tends to adhere to the walls of the passages particularly near the bottom surface, but most of them are eventually returned by the water repellent treatment, and the gas (a) is It is discharged to the outside of the battery through the passage without affecting the presence of the atomized electrolyte and water vapor.

On the other hand, in the conventional explosion-proof filter shown by 6, the movement of the mist-like electrolytic solution and the water vapor (b) is basically the same as that of A, but the passage is narrow, so that the reflux is not easily performed, It will stay inside the passage.

In this state, the droplets (c) of the electrolytic solution that have reached the bottom surface of the filter due to a particularly high vibration adhere to the accumulated mist-like electrolytic solution and water vapor (b), resulting in a state in which a film is formed on the filter surface. Then, when the gas (a) tries to pass in that state, the electrolyte droplets (c) and water vapor (b) naturally leak to the outside of the battery due to the pressure of the gas (a).

Normally, when the electrolytic solution droplets simply reach the filter surface, they are refluxed without completely penetrating inside due to the water repellency. When the explosion-proof filter 6 is not installed with the conventional liquid port plug of FIG. 2A, not only the mist-like electrolytic solution and water vapor (b) but also all electrolytic solution droplets (c) are discharged to the outside of the battery.

These effects will be described based on experimental data. FIG. 4 shows the result of measuring the amount of liquid reduction of the battery according to the ventilation resistance in the bench test, and FIG. 5 shows the result of confirming the presence or absence of the overflow liquid according to the ventilation resistance when the vibration test was performed.

First, FIG. 4 is a simulation of running a real vehicle, and a 100-hour continuous experiment was carried out under the condition that the real vehicle random vibration was applied in the vertical direction while charging with a constant voltage of 14.5 V for each temperature, and the battery weight change. Is measured and compared with the conventional structure.

The results of FIG. 4 show that, compared with the conventional liquid spout that does not use a porous body, especially in a high temperature region, the effect of suppressing liquid reduction appears from around 30 mm of the ventilation resistance value of the porous body, and about 300 to 40.
A great effect was obtained up to around 0 mm.

However, judging from this result alone, the larger the ventilation resistance value, the better the tendency. However, since there is the problem of overflow as described above, it is necessary to make a comprehensive judgment by the experiment of FIG. .

That is, FIG. 5 shows the presence / absence of dilute sulfuric acid component overflow according to the ventilation resistance when vibrating at a constant current of 1 A at 70 ° C. and an acceleration of 10 Hz and 4 G for 10 minutes. As a result, it can be judged that it is a complete overflow.
The area was over 0 mm. From this, it is desirable that the ventilation resistance value in consideration of the overflow property is in the range of 30 to 300 mm.

Particularly, the effect is high when the ventilation resistance value is in the range of 200 to 300 mm. Furthermore, by making the pore size near the surface of the porous body smaller than the pore size inside the porous body, the mist-like electrolyte and water vapor cannot easily enter the inside of the porous body, and remain in the form of water droplets on the surface portion, and only gas is discharged. To do. On the other hand, if the inside of the porous body is also made smaller, the electrolytic solution and water vapor will be retained inside the porous body due to the capillary phenomenon as seen in the conventional explosion-proof filter. The point is to reduce the pore size only near the surface so that the electrolyte and water vapor will not be retained inside the porous body. Actually, there is a method in which the filter has a two-stage sintering temperature and is sintered at a temperature higher than the first temperature so that the pore diameter near the surface is smaller than the inside. The porous body of the present invention is produced by this method. Further, when alumina oxide is used for the porous material as in the present invention, a treatment is required for the purpose of imparting water repellency, but it is usually prepared by post-treatment with silicone oil. In this case, by performing the treatment in two stages, it becomes possible to increase the amount of adhesion in the surface vicinity portion and to cause the water droplets generated in the surface vicinity portion to flow back to the lower portion more quickly and easily. Furthermore, considering the adhesion of electrolytic solution droplets to the porous body, it is possible to reduce the amount of electrolytic solution droplets that reach the porous body by contacting many maze structures with water vapor while reaching the porous body. If possible,
For this purpose, it is necessary to devise a liquid spout structure itself, which is an effective means.

In consideration of this point, the liquid spout structure of the present invention is
The side opening 2 is provided in the direction opposite to the vertical vibration, that is, on the side surface, and the splashproof plate structure has a long maze distance and is easily recirculated.

The grid lead alloy of the present invention was used to form a battery with an electrode plate group in which both positive and negative electrode plates had a calcium content of 0.08 to 0.09%. A hybrid system using an alloy and a calcium alloy for the negative electrode plate does not affect the present invention at all.

[0024]

INDUSTRIAL APPLICABILITY As described above, according to the present invention, in order to cope with various structures of automobiles and road conditions, there is a particularly excellent reduction in the condition that the temperature is remarkably elevated or the electrolyte is lost due to various vibrations. In addition to obtaining liquid characteristics, the battery life can be extended. Furthermore, it is also an easy means for preventing the peripheral equipment of the battery from being damaged without contaminating the upper surface of the battery lid with dilute sulfuric acid of the electrolytic solution. In this way, the reliability of maintenance-free lead-acid batteries for automobiles in the market has been dramatically improved.

[Brief description of drawings]

FIG. 1 is a sectional view of a liquid spout of the present invention.

[Fig. 2] A cross-sectional view of a conventional liquid spout without an explosion-proof filter B Cross-sectional view of a liquid spigot with an explosion-proof filter

FIG. 3 A Partial cross-sectional enlargement and schematic view of porous body of the present invention B Partial cross-sectional enlargement and schematic view of conventional explosion-proof filter

FIG. 4 is a diagram showing the results of measuring the liquid reduction amount when a constant voltage random vibration test is performed for each ventilation resistance.

FIG. 5 is a diagram showing the results of confirming the presence / absence of overflow according to ventilation resistance when vibrating for 10 minutes at 10 Hz and 4 G while performing constant current charging.

[Explanation of symbols]

 1 Bottom opening 2 Side opening 3 Exhaust hole 4 Splash-proof structure 5 Porous body 6 Conventional explosion-proof filter IGASLO Water vapor HA Electrolyte spray

Claims (4)

[Claims] 1. When the air flow rate is 5 l / min, a porous body having a water column manometer value in the range of 30 mm or more and 300 mm or less is mounted in the middle of the gas exhaust passage of the liquid spout, and calcium is attached to the electrode plate grid. A lead acid battery for an automobile, which is made of an alloy. 2. The particle size of coarse particles as a raw material of the porous body is 10
60% or more of particles of 0 μm or more and 300 μm
The lead acid battery for an automobile according to claim 1, wherein the above-mentioned materials are mixed in an amount of 10% or more. 3. The lead acid battery for an automobile according to claim 1, wherein the pore size near the surface of the porous molded product is smaller than that inside the molded product. 4. The lead acid battery for an automobile according to claim 1, wherein a large amount of the water-repellent agent is unevenly distributed near the surface of the molded porous body.