JPH0638153U - Storage battery - Google Patents

Abstract

(57) [Summary] [Purpose] To prevent static electricity from being charged around the liquid spout or the gas vent valve, and to prevent explosion of the storage battery. [Structure] An antistatic cover 6 is provided on a lid portion 2 of a battery case so as to cover a liquid port plug 4 having a gas exhaust passage. The antistatic cover 6 is composed of a molded body molded from a mixed material in which a surfactant, sodium sulfate and a resin are mixed.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a storage battery having a liquid outlet plug or a gas vent valve provided with a gas exhaust passage on the lid of a battery case, and more particularly to a technique for preventing static electricity from charging the lid of the battery container. Is.

[0002]

[Prior art]

 The storage battery has a liquid outlet plug or a gas vent valve having a gas exhaust passage in order to release hydrogen gas and oxygen gas generated by decomposition of the electrolytic solution during charging to the outside of the battery cell of the battery. In general storage batteries such as lead-acid batteries, a resin-made battery case is provided with a resin-made battery case in which a screw-cut liquid inlet for electrolyte injection is formed and a gas exhaust passage is formed at this liquid outlet. The mouth plug is screwed. However, when the storage battery is wiped with a cloth or fluttered, static electricity is charged on the surface of the battery case of the storage battery, and when a spark is generated due to the discharge of this static electricity, in the worst case, it accumulates in the battery case. There was a problem that the gas ignited and the battery exploded. Therefore, as shown in FIG. 5, an explosion-proof filter 105 is provided below a liquid port plug 104 that is equipped with a gas exhaust passage 101 and that is screwed into a liquid port 103 of a lid 102 of the battery case, and sparks enter the battery case. It was considered to prevent this.

[0003]

[Problems to be solved by the device]

 However, such an explosion-proof filter 105 has a complicated structure and is expensive, and since it has a porous structure such as mullite, it cannot sufficiently prevent the explosion of the battery, which is considered to be caused by static electricity. It was Some conventional storage batteries have a cover to cover the liquid spout for the purpose of dust protection, but the conventional cover does not have static electricity charging measures, so the cover is statically charged. However, there was a problem that the static electricity generated sparks as described above.

An object of the present invention is to provide a storage battery having a relatively simple structure and capable of reliably preventing explosion due to electrostatic charging at low cost.

[0005]

[Means for Solving the Problems]

 According to the first aspect of the present invention, a storage battery having a liquid port plug or a gas vent valve provided with a gas exhaust passage in a lid of a battery case is used as a target, and an antistatic protection is provided to cover the liquid port plug or the gas vent valve. Provide a cover.

According to the second aspect of the present invention, the antistatic cover is formed of a molded body formed of a mixed material in which a surfactant, sodium sulfate and a resin are mixed. The blending weight ratio of the surfactant and sodium sulfate is set to 2: 8 to 4: 6, and the content of the surfactant and sodium sulfate in the mixed material is set to 1 to 2% by weight.

[0007]

[Action]

 When the antistatic cover is provided so as to cover the liquid plug or the gas vent valve as in the invention of claim 1, static electricity that causes a spark even if the cover comes into contact with cloth or flutter is applied to the cover. Will not be charged. Therefore, the explosion of the battery can be surely prevented. Moreover, according to the present invention, since it is sufficient to cover the existing liquid port plug or the gas vent valve with the antistatic cover, there is an advantage that the explosion can be prevented at a low cost with a simple structure.

When the antistatic cover is constructed as in the second aspect of the present invention, the surface of the antistatic cover approaches a so-called wet state, and the electric resistance of the surface of the antistatic cover decreases. Therefore, the charging voltage half-life of the antistatic cover can be shortened to effectively prevent electrostatic charge.

[0009]

【Example】

 Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is an exploded perspective view of a lead acid battery for an automobile to which the present invention is applied. In FIG. 1, 1 is a battery case, 2 is a cover of the battery, 3 is a terminal, 4 is a liquid spout, 5 is an upper cover, and 6 is an antistatic cover. The battery case 1 is made of a copolymer resin of ethylene and polypropylene, and has six cell chambers formed therein. The lid 2 of the battery case is welded to the battery case 1 and is made of the same resin material as the battery case 1. Terminals 3 and 3 are fixed to the lid portion 2 of this battery case, and the portion surrounded by the upper lid 5 is screwed to inject the electrolytic solution into each cell chamber in the battery case 1. Two liquid ports (not shown) are formed. Known liquid port plugs 4 made of resin are screwed into the six liquid ports, respectively. A gas exhaust passage for exhausting the gas generated from the electrolytic solution to the outside of the battery case is formed through the liquid port plugs 4 in the axial direction.

The upper lid 5 is made of a resin of the same material as that of the battery case 1, and has a frame-shaped portion 5a surrounding the periphery of the liquid port plugs 4 and a bulging portion 5b juxtaposed to the frame-shaped portion 5a. Consists of. The upper lid 5 is welded to the lid portion 2 of the battery case. A step portion 5a1 on which the antistatic cover 6 is placed is formed on the inner peripheral edge of the frame portion 5a. The bulging portion 5b has a structure that allows batteries to be stacked and stored. The antistatic cover 6 has a flat plate shape capable of being fitted to the step portion 5a1 of the frame-shaped portion 5a of the upper lid 5 so as to cover the upper portions of the six liquid port plugs 4 ... The antistatic cover 6 and the step portion 5a1 have such a shape and dimension that the antistatic cover 6 can be detachably fitted to the frame-shaped portion 5a of the upper lid 5 for supplementing distilled water. Make sure that a slight gap is formed between the antistatic cover 6 and the liquid port plug 4 and between the antistatic cover 6 and the upper lid 5 with the antistatic cover 6 fitted to the step portion 5a1. ing. The gas discharged from the liquid port plug 4 is discharged to the outside of the battery through these gaps.

In this embodiment, the antistatic cover 6 is made of a copolymer resin of ethylene and polypropylene containing sodium alkyl benzene sulfonate (surfactant) with a compounding weight ratio of 2: 8 to 4: 6 and sodium sulfate. A mixed material was prepared by adding and kneading at a ratio of 1 to 2% by weight, and the mixed material was put into a mold having a predetermined shape.

Next, a confirmation test of the antistatic property of the cover will be described. In this test, the relationship between the content of the surfactant and sodium sulfate and the surface resistance value of the antistatic cover made by using the mixed material of each content was investigated. First, a test piece having a diameter of 100 mm and a thickness of 2 mm was prepared by changing the contents of the surfactant and the sodium sulfate having a compounding weight ratio of 2: 8 within the range of 0 to 3% by weight. Then, as shown in FIGS. 2A and 2B, the holder 9 having the positive electrode 7 and the negative electrode 8 is brought into contact with the surface of the test piece P, and the positive electrode 7 and the negative electrode 8 are separated from each other. In the meantime, a voltage of 500 V was applied for 10 seconds at room temperature. Then, the surface resistance value of each test piece P was measured. Table 1 shows the measurement results. It should be noted that Table 1 shows the change in characteristics of each test piece having different elapsed days after molding.

[0013]

[Table 1] From Table 1, it can be seen that the surface resistance value decreases when the content of the surfactant and sodium sulfate is 1% by weight or more. Also, it can be seen that the surface resistance value does not change significantly even if the content exceeds 2% by weight. From these results, it can be seen that an antistatic cover having a small surface resistance value can be manufactured at low cost if the contents of the surfactant and sodium sulfate are 1 to 2% by weight.

Next, using the test piece used in the above-mentioned test, the contents of the surfactant and sodium sulfate and the half-life of the charging voltage of the antistatic cover made by using the mixed material of each content were compared. I investigated the relationship. First, as shown in FIG. 3, while rotating the test piece P in the direction of the arrow in the charging voltage measuring device in which the electrode 10 that causes corona discharge and the charging voltage measuring device 11 are arranged, a 10 KV corona discharge is applied to the test piece P. In addition, the saturated charging voltage was measured. Next, the corona discharge was stopped and the test piece P was left in an atmosphere of 23 ° C. and RH of 50% to attenuate the charging voltage. Then, the decay of the charging voltage was graphed as shown in FIG. 4 to obtain the time (half-life) until the charging voltage became 1/2 of the saturated charging voltage. Table 2 shows the measurement results. Similar to Table 1, Table 2 shows the change in characteristics of each test piece with different elapsed days after molding, and the half-life charging voltage (unit: KV) is shown in parentheses in the table. )It is shown.

[0015]

[Table 2] From Table 2, it can be seen that when the content of the surfactant and sodium sulfate is 1% by weight or more, the half-life of the charging voltage becomes short. Also, it can be seen that the half-life of the charging voltage does not change significantly even if the content exceeds 2% by weight. From this result, it can be seen that the antistatic cover having a short half-life of the charging voltage can be manufactured at a low cost when the content of the surfactant and the sodium sulfate is 1 to 2% by weight.

In this embodiment, the antistatic cover is made of a resin of a copolymer of ethylene and polypropylene, but the antistatic cover may be made of a resin of other material such as polyethylene. it can. Further, in this embodiment, the upper lid 5 is welded to the lid portion 2 of the battery case, and the antistatic cover 6 is fitted to the upper lid 5. However, if the cup-shaped antistatic cover is used, the upper lid 5 is not particularly required. Can also cover the liquid spout 4. In this case, a cup-shaped antistatic cover may be fitted to the lid portion 2 of the battery case with an appropriate fitting structure. Although only the antistatic cover 6 is made of an antistatic material in this embodiment, the lid portion 2, the liquid stopper 4 and the upper lid 5 of the battery case may of course be made of a material having antistatic properties. Is.

Further, although the present invention is an example in which the present invention is applied to a lead acid battery for automobiles, it is needless to say that the present invention can be applied to other accumulators such as sealed type accumulators and accumulators for electric vehicles. For example, when the present invention is applied to a sealed storage battery, the cover does not need to be removed.Therefore, an antistatic cover is welded to the lid of the battery case to cover the gas vent valve and enable gas venting. Good.

[0018]

[Effect of device]

 According to the invention of claim 1, since the antistatic cover is provided so as to cover the liquid outlet plug or the gas vent valve, even if the cover comes into contact with cloth or flutter, static electricity does not charge the cover. Therefore, the explosion of the battery can be surely prevented. Moreover, according to the present invention, since it is sufficient to cover the existing liquid port plug or the gas vent valve with the antistatic cover, there is an advantage that explosion can be prevented at a low cost with a simple structure.

According to the second aspect of the invention, the electric resistance of the surface of the antistatic cover decreases as the surface of the antistatic cover approaches a wet state. Therefore, the half-life of the charging voltage of the antistatic cover can be shortened to prevent electrostatic charge.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of a storage battery according to an embodiment of the present invention.

FIG. 2 (a) is a plan view of a test piece in a test device for examining the surface resistance value of an antistatic cover, and FIG.
FIG. 3 is a side view of a test piece in the test apparatus.

FIG. 3 is a diagram used for explaining a test method for examining the half-life of the charging voltage of the antistatic cover.

FIG. 4 is a diagram showing an attenuation characteristic of a charging voltage of an antistatic cover.

FIG. 5 is a diagram showing an explosion-proof filter provided in a conventional storage battery.

[Explanation of symbols]

 1 Battery case 2 Battery cover 4 Liquid mouth plug 6 Antistatic cover

Claims (2)

[Scope of utility model registration request] 1. A storage battery having a liquid outlet plug or a gas vent valve provided with a gas exhaust passage on a lid of a battery case, wherein an antistatic cover is provided so as to cover the liquid outlet plug or the gas vent valve. A storage battery characterized by that. 2. The antistatic cover is made of a molded product molded from a mixed material in which a surfactant, sodium sulfate and a resin are mixed, and a compounding weight ratio of the surfactant and the sodium sulfate is 2: 8. The storage battery according to claim 1, wherein the content of the surfactant and the sodium sulfate in the mixed material is 1 to 2% by weight.