JPS59160955A - Explosion-proof sealing type alkaline storage battery - Google Patents

Abstract

PURPOSE:To obtain an explosion-proof safety valve having the long stable valve performance under a wide scope of temperature by a method in which a specific amount of carbon black is added to a copolymer of ethylene and propylene as a reinforcer while being vulcanized by organic peroxide for being used as a flexible valve body. CONSTITUTION:Carbon black as a reinforcer is added to a copolymer of ethylene and propylene in the weight ratio of 35-60 parts per 100 parts of copolymer for providing an explosion-proof safety valve 3 vulcanized by organic peroxide. And, for instance, a valve hole 1a is punched in the center of a sealing plate 1 made of nickel-plated steel and a cap 2 of nickel-plated steel is arranged so as to enclose its upper part and to house said flexible valve body 3 in a valve chamber formed by both of the above, while fixing plural projection parts 2b provided on the collar part of the cap 2 to the sealing plate by projection welding in order to constitute the safety valve while the tip of the valve body 3 housed in the valve chamber is pressed to a valve hole 1a for sealing it.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Application The present invention relates to an improvement in an explosion-proof safety valve for a closed alkaline storage tank.

Conventional configuration and its problems Sealed alkaline storage batteries are equipped with an explosion-proof safety device that prevents battery damage and explosion by releasing the gas to the outside when the gas pressure inside the battery rises abnormally due to misuse, etc. Many have the following.

As an explosion-proof safety device, it is desirable to use a return type safety valve that opens when the gas pressure inside the battery reaches a predetermined value or higher to release the scum to the outside, and then returns to the sealed state. This return type safety valve uses a complete combination of an elastic plate made of synthetic rubber or other material that closes the valve hole, a metal spring that is pressure-welded to a neutral sheet metal, and an elastic valve body made of an elastomer such as rubber. In the case of small batteries, the latter method is often adopted because the structure is simple and can be made small, it is easy to create ridges, and the cost is low.

The monthly interest rate used for one neutral body is SBR.

General-purpose products such as chloroprene rubber, SBH mixed with natural rubber or iso7-L/N rubber, and Ayi, a chlorinated butyl rubber with improved processability, have been mainly used.

This divine rubber valve body is molded into a bowl shape and can be conveniently used at temperatures around ordinary width, so it will take several years if it is installed in an appropriate market.
Valve operation performance was maintained at approximately /+i'i over the period of 1.

However, in recent years, the use of the alkaline storage pond in this building has expanded, especially as an emergency backup power source, a power generator that requires rapid charging and discharging such that batteries generate heat, and a computer-related backup source. Unlike conventional methods, there are an increasing number of applications in which water can be used continuously under a wide range of temperatures, including high and low temperatures.

In such applications, ll'i elastic valve bodies also have a diameter of 50 to 70"
You will be exposed to stress, including high temperatures of 20 to 30 degrees Celsius or low temperatures of 120 to 30 degrees Celsius.

In this case, if the rubber valve body is constantly compressed under the ID height of 6 m, the change in material and the increase in permanent deformation will be accelerated, the rebound elastic force will become smaller, the valve operating pressure will decrease, and each time the battery is charged, There were problems in which the valve opened and the electrolyte decreased, and the surface of the valve body softened and became sticky and stuck to the area around the wellbore, causing abnormally high valve opening pressure and causing deformation and damage to the battery. .

As described above, the conventionally used elastic valve bodies have problems in terms of material quality in applications involving high quality stress. .

Therefore, the present inventors have investigated various elastic polymers, including conventional ones.From the viewpoint of heat and cold resistance, silicone rubber and terpolymers of ethylene, propylene, and non-conjugated diene compounds (hereinafter referred to as EPI) have been investigated. The valve body was vulcanized and molded using various market materials (referred to as M), and the valve body was assembled into a 1-ga explosion-proof safety device and tested as a '1'' battery.As a result, silicone rubber The problem is that it has excellent rebound elasticity, but it is weak against tearing, and if it is pressed into the valve hole and the valve operation is repeated, it is likely to crack, and it is a practical elastic valve body, and if it comes into contact with a strong alkali. EPDM, which is widely used as an electrically insulating phase, has the disadvantage of rapid deterioration.EPDM, which is widely used as an electrically insulating phase, cannot be cured by the commonly used vulcanization process using a combination of sulfur and organic peroxide. As a result of the test, there was little material change at high to low temperatures, and the alkali cautery was also good1, but the rebound elastic force and compression set were not superior to those of the conventional example. In addition, as a safety valve, when looking at the change in force over time, the rate of change due to temperature is 5 less than that of the conventional example, but it always includes 6 m. The change in valve operating pressure (reduction rate) is greater than that of conventional valve bodies, for example, chlorobrene valve bodies, and overall (f) shows middle to higher valve operating characteristics than conventional ones, and is particularly superior. It wasn't.

OBJECTS OF THE INVENTION The present invention solves the problems of conventional valve bodies and provides an explosion-proof safety valve that has stable valve function over a wide range of temperatures over a long period of time.

414 DESCRIPTION OF THE INVENTION In order to achieve all of the above-mentioned objects, the present invention is based on a copolymer (elastomer) of ethylene and propylene as an elastic valve body in a sealed alkaline storage battery, and carbon black gold copolymer is added as a reinforcing material to this. It is characterized in that 36 to 60 parts by weight are added per 100 parts of the polymer and vulcanized with an organic peroxide.

Description of examples The details will be explained below using examples.

FIG. 1 is a sectional view of a main part showing a safety valve portion of a sealed Alka 1) storage battery assembled using a single elastic force in an embodiment of the present invention, and the structure will be explained below with reference to this figure.

1 is a sealing plate made of nickel-plated steel, with a valve (Lla) in the center.
A cap 2 made of nickel-plated steel is placed so as to surround the top surface of the cap, and inside the valve chamber formed by the two,
The elastic valve body 3 of the present invention is housed and projection welded to a plurality of protrusions 2b'x provided on the flange of the cap 2 by projection welding. The tip of the valve body 3 housed in the valve chamber presses against the valve hole 1a to close it. A sealing plate equipped with such a safety valve is made by winding 11 false negative electrode plates each impregnated with nickel and cadmium active materials in a spiral shape together with a 7) ζ rotor to create an alkaline electric 11+! A case 4 made of nickel-plated steel and containing a group of electrode plates 6 impregnated with an appropriate amount of liquid i' is sealed. The details are as shown in the annular step 4 provided near the opening 4a+j at the top of the case.
A force socket 6 made of polyamide and having an angled cross-section is installed on the cap 2 as a valve and then opened (the cylindrical part 4a is bent inward and sealed. The cap 2 has a protrusion 2b as a waste discharge part. If it seems that the gap 2C is insufficient, J'J1
Pores 28 may also be provided. Further, 7 is connected to the sealing plate 1 by a lead plate of one of the electrode plate groups.

FIG. 2A shows the assembly of the elastic valve body 3 used for battery safety-fP shown in FIG. 1 1) Shape of 11 j"j K ;
y, the cross section is bowl-shaped 4, and in Fig. 2 B, from the outer periphery to the inside, )
It is a flat elastic valve body with one peeled surface and a melon-shaped upper surface.

The elastic valve body of the present invention is manufactured by vulcanizing and molding a copolymer (elastomer) of ethylene and propylene with peroxide once a month. An elastomer suitable for the purpose of the present invention preferably contains about 15 to 45 mol % of ethylene from the viewpoint of neutrality.

An example of vulcanization molding of an elastic valve body using an elastomer will be described next.

Add 100 parts of elastomer and add it to the vehicle.
As reinforcement 51A (filling) which can change the repulsion elasticity and strength of the snout, a carbon fiber rack is used as reinforcement 51A (filling) 1).
, 5 to 8 parts of process oil (g15) as a softening agent for adjusting the circumference of the sheet, an organic unioxide as an IJ image agent,
For example, 2.5 to 3 parts of dicumyl peroxide, commonly called Dicup, is added. In order to stabilize and accelerate vulcanization, it is recommended to add 0.5 to 2 parts of a vulcanization accelerator such as P-quinone dioxime or acrylic ester3. As a type 11 agent, stearic acid 1
Promotion of vulcanization and vulcanization 1. ! 'i l/: one deletion] 7,
Oxidation tune, lead 5N? Add IS and knead with a roll mixer to make 111L of Komugyu.

Next, 1 gap of this rubber cow m: 1; is shown in Figure 2 A (/l:
The valve body was placed in a valve body mold having the shape shown in the figure, and was pressure molded using a pot press at approximately 160"C to form an elastic valve body (47cm). As explained in the example of Fig. 1, this elastic valve body was A seal having a hole 1a is housed in a valve chamber formed by the plate 1 and the gear knob 2, and pressure is applied to the hole to close it and form a safety force. In addition, if 3 is shown in Figure 1, J-1 is attached to cap 2.
Although it was shown that the pores 2a are provided, in this implementation 1+11, a protrusion for projection welding is provided.
A gap 2C of d is formed between the FJD plate 1 and the brim of the cap, and 1 ul of air can be drawn from there, so the JJ1 pore 2a may be omitted.

A long-term storage test was conducted on the safety battery of the present invention described above and a battery constructed in the same manner using the conventional 1,41! explain.

The following table shows the contents of the test samples.

In addition, the compounding formula marked *1 in the table includes strength 1] value accelerators, softeners (naphthene-based, paraffin-based oils, etc.) other than those listed.
Add anti-aging agents and the like in appropriate amounts according to the formulation of each rubber. *2
The elastomer is shown in the weighing section, 130
1JE force U+jl'l Also, the adhesion of *4 indicates the degree to which each rubber valve body adhered to the valve hole 6 months after the temperature cycle test described above.

Sample 1 is a product of the present invention, 2 to 4 are conventional products, and 5 is a comparative reference product (~, all are initial jυ) The IAI formula was adjusted so that the operating IL force was almost the same. After charging the battery, the battery can be stored. After that, the battery can be stored by supplementary charging every 1 hour and then stored while maintaining the charged state.The test environment was indoors at 1U: ) and -20
A temperature cycle test was performed with 6 hours at °C → 6 hours at normal rM1 -> 10 hours at 66 °C → 24 hours at temperature 2, and 20 of each sample battery was tested under the above test environment for 6 hours.
Stored for ~18 months. After storage, a small hole is made in the bottom of the case 4 of each battery, and a gas pipe is airtightly connected to the hole.
It was connected to a pressurizing device that can be adjusted from 1 to 3.5 ca/ca using compressed air, and the pressure at which the safety valve operates was investigated. For the measurement, after the first activation of the safety valve, the pressure was returned to normal for one minute, and then the pressure was increased again and the second activation pressure was confirmed. Figure 3 shows the results.

Note that OEI] in the figure is the first valve operating pressure after the storage test.

The maintenance rate, .El, indicates the second time, and the maintenance rate is expressed as the average value of each measurement/average value of initial valve operating pressure x 100. As can be seen from the figure, changes over time in the valve operating pressure of a safety valve using only a rubber-based bullet valve body depend on the type of rubber.
) Although there is a slight difference, it shows a relatively small and rapid movement. (Includes l and 11 in the height of ~?'iA At 11 cycles, (deterioration becomes noticeable, +・li,)''l
The difference due to IrC also becomes larger. Among the conventional examples, the molded oven No. 2 is relatively good, but it is insufficient to maintain the valve operating pressure under long-term temperature cycles. As mentioned earlier, in sample 3, the rubber surface softens in the high width region and sticks to the valve hole, resulting in the valve operating pressure being abnormally high at the first time.Moreover, the variation is large. After the second use, the stickiness decreases and the operating pressure drops to about V2 before storage.Therefore, this battery d: Either the container deforms before the well is activated, or the valve operates at low pressure and the lifespan is shortened. It is easy to do.The sample of 4 is
Toon and l'! Although the difference in aging over the l+'1 degree cycle is small, the absolute value of the working pressure is decreasing at a large rate and is insufficient.

Compared to these, the battery equipped with the safety valve of the present invention has a life expectancy of 86-90% after 18 months at room temperature and 6 temperature cycles.
Approximately 90% after 18 months, 80% even after 18 months, and the valve operation rate after 11 months is 1j, and both the absolute value and balance are lower than the conventional one. This can go a long way towards improving lifespan.

In addition, in the embodiments of the present invention, 60 parts of carbon black was used on a gravimetric ratio to 100 parts of ethylene and 10-hylene co-merged as a prescription for the elastic valve body, but when changing the rubber hardness etc., the process Although it is possible to adjust the additive IJ ratio to 1117J with oil, the addition ratio of carbon fluff to the elastomer must be in the range of 35 to 60 degrees. As is clear from Figure 4, which shows the maintenance rate (%) of valve operating pressure after 6 months of temperature cycling, the reinforcing effect decreases when the amount is more than 36 parts, and when the amount is still more than 60 parts, the 1' efficiency is reduced. Because it becomes too expensive,
It is necessary to increase the oil addition rate, and as a result, the rebound elastic force decreases, and the pressure and permanent set increase by J'Fj.
This is because the function of the neutral valve body becomes insufficient due to the I11 mountain.

The ethylene-propylene copolymer used in the present invention is used for electric wires, insulators, etc. that require insulation, and in this case, inorganic materials such as Merck and hard clay are used as reinforcing agents. Even when this was molded and used as an elastic valve body, sufficient repulsive elastic force could not be obtained. As an improvement measure, there is a plan to use it in combination with carbon black, but in that case, although it can be improved considerably, the change over time is large and it is not suitable for practical use. However, the rubber formulation of the elastic valve body of the present invention has insufficient insulation properties and is unsuitable for use as an insulator.

Effects of the Invention As described above, the present invention relates to a closed alkaline storage pond incorporating a simple safety valve using only an elastic valve body, including its height fi, 'i'+. It has significantly improved environmental safety and longevity.

[Brief explanation of the drawing]

Figures 2 and 1 are diagrams showing changes over time in the valve operating pressure of a battery equipped with a closed type alkali in an embodiment of the present invention and a safety valve of a conventional example, and Figure 4 shows the influence of carbon black-containing vinegar on an elastic valve body. It is a diagram. 1... Sealing plate, 1a... Valve hole, 2... Cap, 3... Elastic valve body, 4... Case, 5
... Plate group, 6... Kaskerato.

Claims (1)

[Claims] A copolymer of ethylene and propylene is added with carbon black as a reinforcing material at a weight ratio of 3 parts per 100 parts of the copolymer.
An explosion-proof sealed alkaline storage battery comprising an explosion-proof safety valve added with 5 to 60 parts and vulcanized with organic peroxide.