JPH0945309A - Lead-acid battery and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance a degree of adhesion of a polar column and a bushing by forming a melting area interface between a bushing and a polar column base material in an almost W shape when a terminal of the polar column connected to a plate group is welded to a lead bushing formed in a cover of a battery jar. SOLUTION: An electrode plate group where positive and negative electrode plates and separators are alternately superposed on each other is housed in a battery jar compose of plural cell chambers, and a polar column 4 is connected to the plate group. A lead bushing 2 is formed in a battery cover to cover the battery jar by insert molding, and this bushing 2 is inserted into the polar column 4, and wedding is performed. At this time, a tip part of the polar column 4 is formed in a shell shape so that an outside diameter of the polar column 4 opposed to an upper end part of the bushing 2 becomes about 75 to 85% to an inside diameter of a bushing upper end part, and the tip part of the polar column 4 is projected from an upper end of the bushing 2 so that a clearance 6 exists on its periphery. When the polar column 4 and the bushing 2 are welded together in this condition, an interface of a melting area 8 is formed in an almost W shape, and a degree of adhesion of the polar column 4 and the bushing 2 can be enhanced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a lead acid battery and a method for manufacturing the same.
In particular, it relates to a terminal portion obtained by welding a pole column and a lead bushing led out from the inside of the battery case, and a method for forming the terminal portion.

[0002]

2. Description of the Related Art A lead storage battery has a structure in which a positive electrode plate, a negative electrode plate and a separator are alternately stacked in a battery case consisting of a plurality of cell chambers. The positive and negative terminals of such a lead-acid battery are connected to the electrode plates located at the left and right ends of the battery case, and the poles drawn out from inside the battery case are inserted into the lead bushing insert-molded on the battery cover. And are welded together. At this time, if the relative positional relationship between the battery case and the battery lid is displaced, at the same time, the positional displacement is also generated between the pole post and the bushing. When the pole column is inserted into the lead bushing in such a state, the tip of the pole column comes into contact with the bottom surface of the bushing. This contact sometimes damages the poles and bushings.

Further, when the outer diameter of the pole column is smaller than the inner diameter of the bushing, a gap is created between the pole column and the bushing. Due to this gap, displacement is allowed within the range of the difference between the outer diameter of the pole and the bushing and the inner diameter. Therefore, the lead parts such as bushings and poles are not damaged due to displacement. However, when the bushing and the pole are welded, the lead alloy in a molten state flows down to the lower part through the gap. When the molten lead alloy drops on the upper part of the shelf, the positive and negative electrode plates are electrically contacted while straddling the upper part of the separator, causing a short circuit.

[0004]

In order to suppress the flow of molten lead during welding, the inner diameter of the bushing and the outer diameter of the pole column are set so that no gap is created between the pole column and the bushing. It was However, in such a lead storage battery, it is difficult to accurately position the bushing and the pole column during manufacturing, and the lower surface of the bushing and the upper end surface of the pole column are easily contacted and damaged. When the degree of damage such as dents and omissions in these lead parts increases, the amount of lead in the welded part decreases, and the size of the formed terminal is J
It falls below the standard value defined in the IS standard.

In general, the lower part of the pole is connected to the pole plate through a shelf portion connecting the ears of the same polarity pole plate to each other. Therefore, when the upper ends of the poles come into contact with the bushings, an excessive load is applied to the pole plates and the shelves. There is also a problem that the excessive load on the electrode plate causes the electrode plate to be deformed, which leads to poor battery performance.

Further, the welding of the terminal portion is carried out by melting the upper portion of the bushing into which the poles are introduced by the flame of the burner and then solidifying this. Normal,
The upper end portion of the pole column is formed in a cylindrical shape having an outer diameter substantially the same as the inner diameter of the bushing, and the pole column is inserted into the bushing until the upper end surfaces thereof are substantially the same. The lead alloy in a molten state forms a dish-shaped molten area toward the lower part of the terminal. This fusion zone gradually expands toward the lower portion of the terminal as the welding time increases. As described above, when there is no gap between the bushing and the pole, the molten lead alloy does not drip inside the battery case. Further, the pole column and the bushing are not joined by the molten lead alloy flowing into the gap. For this reason, the range in which melting is performed, the so-called welding depth, is determined by the melting region. To obtain a sufficient welding depth,
It is necessary to take measures such as lengthening the welding time or increasing the firepower. However, due to the increase in the thermal power, the lead alloy in the molten state may be scattered, and in this case, the amount of lead in the molten region decreases. The scattering of molten lead not only reduces the size of the terminals due to the decrease in the amount of lead in the molten area, but also keeps the welded state constant by clogging the burner crater with the lead alloy scattered to the outside. In addition to disappearing, it causes new problems such as frequent crater cleaning. On the other hand, an increase in welding time has a problem that productivity is lowered.

[0007]

In order to solve the above-mentioned problems, a method of manufacturing a lead storage battery according to the present invention is a method of manufacturing a lead storage battery, wherein a pole column having a shell-shaped tip is inserted into the bushing, and then the pole column and the bushing are inserted. Is used for welding, and when the pole column is inserted into the bushing, the pole column facing the bushing upper end has an outer diameter of 75 to 85% of the bushing upper end inner diameter. Further, the fusion zone interface is welded so as to have a substantially W shape.

[0008]

With respect to the inner diameter of the upper end portion of the bushing insert-molded in the lid, the diameter of the portion of the pole column, which is led out from the inside of the battery case, corresponding to the upper end portion of the bushing is reduced to 75 to 85% and the tip portion Uses a pole-shaped pole. Therefore, even if the positions of the poles are misaligned when the poles are inserted into the bushing, the poles are inserted into the bushing along the inclination of the shell-shaped tip. Therefore, the upper end of the pole and the lower end of the bushing do not come into contact with each other, and they are not damaged.

When the bushing and the poles are welded to each other by using a gas burner, melting starts from the apex of the poles formed in a shell shape and gradually melts along the inclination of the tip of the poles. The area expands. The lead alloy in a molten state flows into the gap between the pole column and the bushing and welds them together. Therefore, by adjusting the shape of the pole column tip portion, the welding depth from the upper end portion of the bushing can be easily changed during welding, which enables stable terminal welding in a welded state. Furthermore, the outer diameter of the pole portion contacting the lower part of the bushing is almost equal to the inner diameter of the bushing,
The molten lead alloy does not flow down into the battery case.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a perspective view of a lead storage battery produced by the manufacturing method of the present invention. In FIG. 1, 1 is a lid, 2
Is a bushing insert-molded on this lid, 3 is positive,
A group of electrode plates composed of a negative electrode plate and a separator, 4 is a pole column according to the present invention whose tip portion is formed in a bullet shape, and 5 is a battery case, respectively.

The lead parts for the poles are welded to the ledges that connect the ears of the same polarity plates of the plate group housed in the battery case,
The poles project upward from the inside of the battery case. When the battery case 5 and the lid 1 are fitted together and they are welded, the poles are inserted and fitted into the bushing 2 provided on the lid 1. Since the pole pillar according to the present invention has the tip portion formed in a bullet shape, it can be easily inserted into the bushing, and the pole pole is not deformed due to the contact between the pole pole tip portion and the bushing.

The pole column inserted into the bushing is exposed to the fire of the gas burner from above and is subjected to terminal welding. FIG. 2 shows a sectional view of the pole 4 and the bushing 2 before the terminal welding. At this time, the tip of the pole 4 projects from the upper end of the bushing 2. Further, the pole column is formed such that the outer diameter of the pole column corresponding to this portion is smaller than the inner diameter of the upper end portion of the bushing, and a gap 6 exists around the pole column. As is apparent from FIG. 2, the gap is gradually reduced toward the lower portion of the bushing because the pole column is formed in a bullet shape, and the bushing and the pole column are in contact with each other in the lower portion of the bushing.

During welding, the portion of the pole column projecting from the upper end of the bushing is in a molten state, and the melted lead flows into the gap between the bushing and the pole column. By melting the lead alloy at the tip of the pole and flowing into the gap, a terminal having a predetermined shape is formed.

On the other hand, FIG. 4 shows a perspective view of a lead storage battery using a pole that has been conventionally used. The configurations of the bushing 2 mounted on the battery lid 1, the battery case 5 and the electrode plate group 3 housed therein are similar to those of the present embodiment, and the poles 7 are drawn out from the inside of the battery case. There is. Further, as is clear from FIG. 4, the tip portion is formed in a cylindrical shape. The outer diameter of the pole column tip portion and the bushing inner diameter have substantially the same value, and strict positioning is required when inserting the pole column 4 into the bushing 2. When the positions of the two are displaced, the upper end of the pole column comes into contact with the lower surface of the bushing and is damaged.

The state of occurrence of breakage of lead parts and the welding depth of the terminal portion after welding in the construction of such a lead storage battery were examined.

The ratio of the outer diameter of the pole that opposes the upper end surface of the bushing during insertion to the inner diameter of the bushing (hereinafter referred to as the pole inner diameter ratio) is changed within the range of 70 to 90% to make the tip end like a bullet. The formed poles and conventional poles were used, and with these poles being led out from the inside of the battery case, a battery lid was attached to the battery case to form a lead acid battery. This time,
A pole is inserted into the bushing attached to the battery lid.
Welding was performed so that the upper portion of the terminal portion in which the pole was inserted into the bushing was in a molten state. In order to adjust the welding depth of the terminal portion, the pressure of the LPG gas supplied to the gas burner and the oxygen pressure were changed under two types of conditions to adjust the thermal power during welding. Table 1 shows the relationship between the shape of the poles and the damage and welding conditions.

[0018]

[Table 1]

In the conventional pole column whose tip portion is formed in a cylindrical shape, they come into contact with each other when the bushing is inserted, and in addition to these lead parts, the electrode plate is broken at a rate of about 5%. On the other hand, the pole column of the present invention, the tip of which is formed into a bullet shape, is quickly and surely inserted into the bushing. A lead storage battery having a pole column inner diameter ratio of 90% and a small gap between the bushing and the pole column was damaged by about 1%, but a lead storage battery using a pole column having a pole column inner diameter ratio of 15% or more, No damage to the lead parts was observed.

Next, after the bushing and the pole are welded to form a lead storage battery, the center of the terminal portion is cut in the height direction,
Weld depth at the interface between bushing and pole was measured.
FIG. 6 shows a cross-sectional shape of a terminal portion using a conventional pole. In the conventional pole, the tip is formed in a cylindrical shape,
As shown in FIG. 5, there is no gap near the upper end of the bushing. Therefore, during welding, the flame of the gas burner is melted only from the upper ends of the poles and bushings. Therefore, as shown in FIG. 6, an arc-shaped melting area is formed. When the heat power is weak, the fusion zone is formed in a dish shape as shown in FIG. 6 (A), and only a welding depth of about 2 mm can be obtained from the upper end of the terminal at the interface between the bushing and the pole. At the time of strong heat, a convex fusion zone having the apex at the center of the pole column shown in FIG. 6B is formed. The welding depth at this time was 4 mm. As the thermal power increases, the convex melting zone expands toward the bottom of the pole. For this reason, at the interface between the bushing and the pole, it is not possible to obtain a welding depth that matches the increase in the fusion zone.

On the other hand, in the pole column of the present invention, the tip of which is formed in a bullet shape, the flame of the gas burner enters the gap between the terminals. Therefore, the inner surface of the upper portion of the bushing and the surface of the side surface of the pole column are also heated and melted. In addition, the tips of the poles are melted and flow into the gap to form the terminals. FIG.
Fig. 3 shows a cross-sectional view of the central portion of the terminal portion where the pole column inner diameter ratio is set to 20% and the heating power is changed to perform welding. When the fire power is weak, the flame of the burner is melted on the upper and inner surfaces of the bushing and the side surface of the pole. At this time, the cross section of the central portion forms a W-shaped melting zone having a lower apex at the boundary between the inner surface of the bushing and the pole. After welding, in the cross section of the central portion, as shown in FIG. 3 (A), the interface between the base material of the bushing and the pole and the molten region 8 in the molten state remains in a substantially W shape. However, as the thermal power increases, the inside of the pole becomes molten, and the melting region approaches the trapezoidal shape with the shorter side shown in FIG.

Regarding the relationship between the inner diameter ratio and the welding depth, as the inner diameter ratio of the pole column increases, the gap between the bushing and the pole column becomes
As it is present under the bushing, the molten lead spreads to the bottom of the bushing during welding, and the welding depth increases. When the inner diameter ratio of the poles is 90%, the gap between the bushing and the bushing is small, and therefore only a welding depth of about 3 mm can be secured in melting under a low heat condition. On the other hand, when the inner diameter ratio reaches 30%, a gap is partially formed at the bottom of the bushing, and the lead alloy in a molten state travels along the pole column and sags into the battery case. Thus, from the viewpoint of the molten state, the pole column inner diameter ratio is preferably 75% or more.

As is clear from Table 1, a deeper welding depth can be obtained when the heat is high than when it is low. However, the lead alloy in a molten state is scattered by the flame, and the burner crater is apt to be clogged. The clogged burner lacks flame stability and cannot obtain a constant molten state. For this reason, it is preferable that the heating power during welding is low.

As described above, according to the present embodiment, the inner diameter ratio of the pole column whose tip portion is formed in a bullet shape used in the method for manufacturing the lead storage battery of the present invention is such that when the pole column is inserted into the bushing. Judging from the damage situation that occurs, 85% or less is desirable,
Judging from the situation of occurrence of problems such as dripping of molten lead into the battery case during welding, 75% or more is preferable.

[0025]

EFFECTS OF THE INVENTION By inserting a pole column having a bullet-shaped tip into a bushing and then welding the pole column and the bushing, the occurrence of damage to lead parts is significantly suppressed, and The degree of adhesion between the pillar and the bushing can be increased.

[Brief description of drawings]

FIG. 1 is a perspective view of a lead-acid battery prepared by the construction method of the present invention.

FIG. 2 is a cross-sectional view of the pole and bushing of the present invention before performing terminal welding.

FIG. 3 is a sectional view of the central portion of the terminal portion according to the present invention after welding.

FIG. 4 is a perspective view of a lead acid battery prepared by a conventional manufacturing method.

FIG. 5 is a sectional view of a conventional pole and bushing before terminal welding.

FIG. 6 is a sectional view of a central portion of a conventional terminal portion after welding.

[Explanation of symbols]

 1 Lid 2 Bushing 3 Pole plate group 4 Pole column 5 Battery case 6 Gap 7 Conventional pole column 8 Melting area

Claims (3)

[Claims] 1. A positive electrode plate group, in which positive and negative electrode plates and separators are alternately stacked, is housed in a battery case consisting of a plurality of cell chambers, one end of which is connected to the electrode plate group, and the other end of which is a battery case. A lead-acid battery having a terminal portion welded to a lead bushing insert-molded on a battery cover that covers the bushing in the central cross section of the terminal portion and the melting region interface of the pole base material is approximately W.
A lead storage battery, which is formed in a letter shape. 2. An electrode plate group in which positive and negative electrode plates and separators are alternately stacked is housed in a plurality of cell chambers of a battery case, and an upper part of the battery case and a battery lid which covers the opening of the battery case are fitted together. , One end of which is connected to the electrode plate group and which is led out to the upper part of the battery case is inserted into a lead bushing insert-molded on the upper surface of the battery lid,
In a method of manufacturing a lead storage battery in which the pole post and a lead bushing are welded, a pole post having a shell-shaped tip is inserted into the bushing, and then the pole post and the bushing are welded to form a terminal part. Manufacturing method. 3. The method for producing a lead storage battery according to claim 2, wherein the pole column facing the bushing upper end has an outer diameter of 75 to 85% of the bushing upper end inner diameter.