JP2600508B2 - Lead-acid battery group welding method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for group welding lead storage batteries.

[0002]

2. Description of the Related Art Conventionally, group welding of lead-acid batteries is roughly classified into two.
Was done in the usual way. One is to insert the ear between the comb-shaped chills, heat and melt the lead alloy welding rod with a gas burner from above, pour this between the ears, and simultaneously melt the ears. A burner type that forms a strap and welds to the ears. The other is to pour molten lead alloy (hereinafter referred to as “strap alloy molten metal”) into a concave portion of a strap-shaped mold, and immediately after this strap alloy This is a cast-on type in which the ear is immersed in the molten metal to solidify the strap alloy melt and weld it to the ear.

In the case of group welding by the cast-on method, generally, (a) removal of an oxide film by brushing the electrode plate ears, and (b) a relatively large area of the ears 1 as shown in FIG. Applying and drying flux 2 to the applied ear part length 3 to 8 mm), (c) group welding by cast-on,
Is performed.

[0004] In addition, a method has been proposed in which, after improving the weldability, a pole lug is coated and then subjected to group welding.
The technology relating to this is disclosed in Japanese Patent Publication No. 63-5863. However, even if the coating is performed, an oxide film always exists on the surface, so that it is still necessary to use a flux to remove the oxide film.

[0005]

When group welding is performed using a flux with or without a coating, a hole called a blow hole 3 is formed in the strap 4 as shown in FIG.
Inside, especially at the fusion boundary between the electrode plate ear 1 and the strap alloy, and it is difficult to obtain a good welding state.

The reason is as follows. Originally, group welding by cast-on method involves pouring a lead alloy melt into a mold, immersing the electrode plate ears in it, and solidifying the whole, and the required time is as short as 10 seconds at most. There is a feature. On the other hand, as shown in FIG. 3, a large amount of the flux 2 applied to the surface of the ear portion 1 is decomposed by heat applied at the time of welding to become a gas. Because welding is short,
This solidification is completed before this gas has not completely diffused out of the system, and remains in the strap 4 as a blowhole 3 as shown in FIG.

[0007] In addition, in order to obtain a good welding condition, it is necessary to use FIG.
It is necessary that the molten metal of the strap alloy constituting the strap 4 wets the surface of the ear part 1 as shown in FIG. 1 and has a form called a fillet 5 which contributes to preventing the dilute sulfuric acid as the electrolytic solution from entering the inside of the strap. .

However, in the conventional method, particularly when the ear 1 is not coated, the ear 1 is hardly wet and the fillet 5 is insufficiently formed. Further, when the cathode strap is exposed in a hybrid type battery, corrosion of the lead alloy is promoted by infiltration of dilute sulfuric acid, and there is also a problem that breakage of a weld portion occurs.

[0009] It is an object of the present invention is less of a blow hole,
Another object of the present invention is to provide a method for group welding lead-acid batteries capable of obtaining a strap having sufficient fillet formation.

[0010]

The means of the present invention for achieving the above object will be described. The method of group welding of lead-acid batteries according to the present invention comprises a Pb-Ca system or a Pb-Sb system having a low Sb content. Pb-S
When forming a strap by mutually welding by a cast-on type using a b-based alloy or pure lead, the surface of the ear portion is coated with a metal having a lower melting point than a lattice alloy, and then only on the tip of the ear portion. The method is characterized in that flux is applied and group welding is performed.

[0011]

The reason why the above means is advantageous for obtaining a strap having a small number of blow holes and sufficient fillet formation is as follows.
It is as follows.

(A) The tip of the ear part is extremely easily melted by the effect of the flux (cleaning by removing the oxide film on the metal surface), and the temperature of the ear part rapidly rises due to heat conduction from the molten strap alloy. . Therefore, it becomes easier for the molten strap alloy to wet the ears.

(B) Since only a necessary minimum amount of the reducing agent is used, it is possible to minimize the gas generated by decomposition.

(C) Since the melting point of the coating layer itself is low, the surface of the ear is melted in a very short time, and the strap alloy and the ear can be integrated.

[0015] By the above-described operation, the number of blow holes is reduced.
In addition, it is possible to perform group welding with sufficient fillet formation.

[0016]

Example: Six cathode plates made of a Pb-0.7Ca-0.5Sn alloy were
Group welding was performed by a cast-on method using a strap alloy composed of a -3Sb-0.1As alloy. The method is described below.

First, the width is adjusted using a steel rotating brush.
A 13 mm electrode lug was polished over a length of 10 mm. Next, apply the flux to the entire ears and use a drier at 200 ° C.
Hot air for 30 seconds to dry. Next, the ear portion was immersed in a metal Sn bath set at a temperature of 240 ° C. for 10 seconds, and the entire ear portion 1 was coated with Sn as a low melting point metal 6 as shown in FIG. Thereafter, the ear 1 was lightly contacted with a sponge containing the same flux as described above, and the flux 2 was applied only to the tip. Next, the injection temperature of the strap alloy composed of the Pb-3Sb-0.1As alloy was 550 ° C, the mold temperature was 200 ° C, and the immersion depth of the lugs into the mold (the electrode lugs were not poured into the mold. 3mm, ear immersion timing (time from injection of the molten alloy until the ear is immersed)
The ears 1 were group welded under a cast-on condition of 1.0 second.

FIG. 2 shows the state of the strap 4 formed by group welding in this way. In such a group welding method for lead-acid batteries, the electrode lug 1 is coated with a low-melting metal 6, and only the tip is coated with a flux 2 made of a reducing agent. Since the amount of gas generated by the decomposition is reduced, the number of blowholes 3 generated inside the strap 4 is reduced, the generation of internal defects can be suppressed, and the fillet 5 can be easily formed.

In addition, Table 1 shows the results of group welding experiments under several conditions including the conventional method (with coating).

[0020]

[Table 1]

In Table 1, when the coating was applied to a relatively wide area of the ears of 2 to 5 mm, the number of blowholes generated was large, whereas only the tip of the ears according to the present invention (1 mm or less).
When it was applied to, it decreased remarkably. In addition, 9 instead of Sn
Similar results were obtained when a Pb-Sb-based alloy containing 1313% by weight of Sb was coated.

[0022]

As described above, in the group welding method for lead-acid batteries according to the present invention, the low-melting point metal is coated on the lug of the electrode plate, and a flux is applied only on the tip thereof to cast on. As a result, the amount of gas generated by the decomposition of the flux is reduced, so that the number of blowholes generated inside the strap is reduced, the generation of internal defects can be suppressed, and the fillet can be easily formed. For this reason, penetration of the electrolytic solution can be prevented, and breakage of the weld due to corrosion of the lead alloy can be prevented. According to the method of the present invention, since the quality of the strap can be greatly improved, the industrial value is extremely large. In particular, in the case of the method of the present invention, Sn powder
And paste the paste with the flux component powder on the ear
And heat-melt it, and then group weld.
Instead, simply coat the ear with a low melting point metal
After applying flux only to the tips of the ears,
Therefore, heating after paste formation process and paste application
Group welding with few blow holes easily without taking a melting process
It can be performed.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing an example of a processing state of an ear portion before cast-on according to a method of the present invention.

FIG. 2 is a longitudinal sectional view of a strap formed by the method of the present invention.

FIG. 3 is a longitudinal sectional view showing an example of a processing state of an ear portion before cast-on according to a conventional method.

FIG. 4 is a longitudinal sectional view of a strap formed by a conventional method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ear part 2 Flux 3 Blow hole 4 Strap 5 Fillet 6 Low melting metal

Claims (1)

(57) [Claims] 1. The lugs of a plurality of electrode plates formed of a lattice made of a Pb-Ca-based alloy or a Pb-Sb-based alloy having a low Sb content,
When the strap is cast and formed by the cast-on method using a Sb-based alloy or pure lead, a metal having a lower melting point than the lattice alloy is coated on the surface of the ear, and then only the tip of the ear is formed. A group welding method for lead-acid batteries, characterized in that flux is applied to the group to perform group welding.