JP2002110114A - Lead-acid battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lead-acid battery having terminals in which a lead pole is inserted into a lead bushing to be welded together, therein securing a depth of the junction between the lead pole and lead bushing is secured, preventing a lead drip in welding, and suppressing the occurrence of crack in a junction between the lead pole and lead bushing, which is remarkably found especially in negative electrode absorbing type lead-acid battery. SOLUTION: A protrusion 4 disposed around a lead pole 3 is welded to the inner wall of a lead bushing 2. In a state in which the lead pole 3 is inserted into the lead bushing 2, the internal diameter of the part corresponding to the protrusion 4 on the inner wall of the lead bushing 2 is indicated as R. The internal diameter of the lead bushing 2 positioned above the part corresponding to the protrusion 4 is indicated as RU. The internal diameter of the lead bushing 2 positioned below the part corresponding to the protrusion 4 is indicated as RL. In such a case, the R is wider than RU and RL.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a terminal of a lead storage battery.

[0002]

2. Description of the Related Art The structure of a terminal sealing portion of a lead-acid battery, particularly a large-sized industrial lead-acid battery used for an emergency power supply or the like, has conventionally been as shown in FIG. That is, the lead pole 30 connected to the battery electrode plate group is inserted into the lead bushing 20 embedded in the battery case cover 10 by insert molding or the like, and the lead bushing 20 and the lead pole 30 are welded. Was.

Usually, the lead bushing 20 is provided with a taper 20a so that its inner diameter increases downward, that is, toward the inside of the battery case. Are almost the same. When the lead bushing 20 and the lead pole 30 are welded, the lead pole 30 is welded.
Is melted by a heat source such as a burner flame, and the molten lead is allowed to flow between the lead pole 30 and the lead bushing 20 to cool and solidify, thereby joining the lead bushing 20 and the lead pole 30. The part 60 was formed.

In such a conventional structure, when the outer diameter of the lead pole 30 is too small with respect to the inner diameter of the lead bushing 20, molten lead generated at the time of welding the lead pole 30 and the lead bushing 20 is dripped. It flows into the tank. Such dripping lead causes a short circuit between the positive electrode and the negative electrode constituting the electrode plate group. When a burner flame is used for welding, the part 50 of the lead pole 30 makes it difficult for the burner flame to reach the welded portion, and the depth L of the joint portion 60 is shallow, so that poor welding is likely to occur.

Further, in order to prevent the molten lead from dropping from the joint 60, it is necessary to minimize the gap between the lead pole 30 and the lead bushing 20 below the joint 60, that is, inside the battery case. However, in particular, the lead pole 30 of the negative electrode
The surface of the battery corrodes during use of the storage battery, and lead sulfate is generated as a corrosion product. This corrosion product causes the outer peripheral portion of the lead pole column 30 to expand in volume, and generates a stress on the inner wall of the lead bushing 20 in the outer peripheral direction of the lead bushing 20. This stress acts to peel off the joint 60 between the lead pole 30 and the lead bushing 20, resulting in a crack in the joint 60,
Problems such as leakage of electrolyte through the crack and loss of airtightness in the storage battery cause a problem of capacity reduction. In particular, when the depth L of the joint 60 is not sufficiently ensured, a crack is generated in the joint 60 in a relatively short time. It has also been found that the occurrence of such corrosion is greatly affected by the amount of gap between the lead bushing 20 and the lead pole 30. Specifically, corrosion progresses remarkably in a place where the gap amount is 1 mm or less, and hardly progresses in a place where the gap amount exceeds 1 mm. This is because the corrosion rate is affected by the degree of retention of the electrolytic solution in the gap. It is also affected by the concentration of sulfuric acid in the electrolyte held in the gap.

This problem hardly occurs in a liquid-type lead-acid battery in which the entire electrode group is immersed in an electrolytic solution. This is a problem that is remarkably generated in a negative electrode absorption type lead-acid battery in which an oxygen gas generated during charging is absorbed by a negative electrode by impregnating the electrode group with an electrolytic solution.

[0007]

SUMMARY OF THE INVENTION The present invention relates to a lead-acid battery as described above, which ensures the depth of the joint between the lead pole and the lead bushing, and is particularly remarkable in a negative electrode absorption type lead-acid battery. An object of the present invention is to suppress the occurrence of cracks at the joint between a lead pole pillar and a lead bushing caused by corrosion of the pillar.

[0008]

In order to solve the above-mentioned problems, the invention according to claim 1 of the present invention comprises a lead bushing provided on a battery case cover and a lead pole inserted through the lead bushing. In the lead storage battery having a joined configuration, a lead storage battery is shown in which a protrusion is provided on the outer periphery of a lead pole and the protrusion is joined to the inner wall of a lead bushing. According to a second aspect of the present invention, there is provided a lead-acid battery having the configuration according to the first aspect, wherein a lead corresponding to a protrusion on an inner wall of the lead bushing in a state where the lead bushing and the lead pole are inserted. the bushing inner diameter R, a lead bushing inner diameter R _U in the above the portions corresponding to the protrusions, if the lead bushing inner diameter was R _L to R> R _L at lower than a portion corresponding to the protrusion, R> R _U. According to a third aspect of the present invention, there is provided a lead-acid battery having the configuration according to the second aspect, wherein the inner diameter of the lead bushing becomes larger as going upward from a portion corresponding to the projection on the inner wall of the lead bushing. FIG. 4 shows a lead-acid battery provided with a tapered portion and a second tapered portion in which the inner diameter of the lead bushing increases as going downward from a portion corresponding to a protrusion on the inner wall of the lead bushing. According to a fourth aspect of the present invention, there is provided a lead-acid battery having the structure according to any one of the first, second and third aspects, wherein the lead-acid battery has almost no electrolytic solution released from the electrode group and is generated inside the battery case. The oxygen gas to be absorbed is absorbed by the negative electrode. According to a fifth aspect of the present invention, there is provided a lead-acid battery having the configuration according to any one of the first, second, and third aspects, wherein the electrode group is exposed from the electrolyte surface so that the inside of the battery case is reduced. The oxygen gas generated is absorbed by the negative electrode.
According to a sixth aspect of the present invention, in the lead-acid battery having the configuration of the fourth or fifth aspect, a ratio of a height dimension to a width dimension of the electrode plates constituting the electrode group is more than 1.5. It is characterized by the following.

[0009]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a view showing a state before welding of a terminal portion of a lead storage battery of the present invention. In FIG. 1, 1 is a battery case cover, 2
Indicates a lead bushing. A lead pole 3 connected to a strap portion (not shown) obtained by collectively welding ears of electrode plates constituting an electrode plate group (not shown) is inserted. A protrusion 4 is provided on the outer periphery of the lead pole 3. The protruding portion 4 has a tapered portion 4a whose pole diameter decreases as it goes upward, that is, toward the outside of the battery, and a taper portion 4b whose pole diameter decreases as it goes downward, that is, toward the inside of the battery. A projection 4 is formed between these two tapered portions 4a and 4b so that the diameter of the pole is substantially constant. The inner diameter of the lead bushing 2 has a first tapered portion 2a whose inner diameter increases as it goes upward from the lower end of the tapered portion 4a provided on the protrusion 4, and a second taper portion whose inner diameter increases as it goes downward. Is provided. Since the first tapered portion 2a and the second tapered portion 2b are provided on the inner diameter of the protrusion 4 and the lead bushing 2 on the lead pole 3, the protrusion spreads upward from the protrusion 4 as a boundary. A space 5 and a space 6 opened below are formed.

A burner flame is applied to the space 5 between the lead pole 3 and the lead bushing 2 to melt the projection 4 adjacent to the space 5 and the inner wall of the lead bushing 2 and join them together, as shown in FIG. 2) is formed.

According to such a means, the joint 7 can be directly heated by the burner flame at the time of welding.
Can be sufficiently secured. Space 5
The width of the lead decreases as it goes down, so that the flow of molten lead into the battery can be suppressed.

A space 6 extending downward is formed by the second tapered portion 2b provided on the inner wall of the lead bushing 2. By forming such a space 6, even if corrosion products accumulate on the outer periphery of the lead pole 3, it is possible to suppress the corrosion deposits from exerting stress on the inner wall of the lead bushing 2. In addition, when the battery is used in a high-temperature atmosphere in which the battery is not usually determined, the corrosion rate particularly at the negative electrode pillar is high, and the deposition amount of the corrosion product increases. In such a case, the space 6 is filled with the corrosion product and stress is applied to the inner wall of the lead bushing 2. However, since the joint depth L can be larger than that of the conventional one, cracks in the joint 7 can be prevented. Can be suppressed.

Here, the first tapered portion 2a and the second tapered portion 2b provided on the lead bushing 2 are provided to form the spaces 5 and 6, and the protrusions 4 are formed on the outer periphery of the lead pole column 3. Is provided, and the projection 4 and the inner wall of the lead bushing 2 are welded. When the lead bushing 2 and the lead pole 3 are inserted, the inner diameter of a portion corresponding to the projection 4 on the inner wall of the lead bushing is adjusted. R, the inner diameter of the lead bushing 2 above the portion corresponding to the protrusion 4 is R _U , and the inner diameter of the lead bushing 2 below the portion corresponding to the protrusion 4 is R _L
And it may be R> R _L, and R> R _U in the case of.

For example, this object can be achieved even if the inner diameter of the lead bushing 2 is increased stepwise. However, considering the castability of the lead bushing 2 and the like, it is needless to say that providing the tapered portion is more excellent in productivity.

The above-described structure is preferably applied to a sealed lead-acid battery having a limited amount of electrolyte. Sulfuric acid in the electrolytic solution attached to the pole combines with the lead alloy constituting the pole to form lead sulfate. Due to this reaction, the concentration of sulfuric acid in the electrolytic solution attached to the pole decreases, and a neutral region is formed. Further, when a part of the surface of the pole is oxidized, the region changes from the neutral region to the basic region, and the corrosion of the pole is further accelerated. In sealed lead-acid batteries, the amount of liquid is limited and only the amount of sulfuric acid creeping up the pole surface is replenished, so the polarity of the pole surface frequently changes from neutral to basic, resulting in corrosion of the pole surface. This is because the speed increases.

Further, when the electrode plate has a vertically long shape, the electrolyte is stratified by charging and discharging of the storage battery.
Since the concentration of sulfuric acid in the electrolyte solution on the upper part of the electrode plate group extremely decreases, the above-described negative polarity corrosion progresses more remarkably. Therefore, it is preferable to employ the configuration of the present invention.

[0018]

Embodiments of the present invention will be described below.

With respect to the structure of the present invention and the structure of the comparative example, the lead pole and the lead bushing were welded, and the occurrence rate of dripping lead and the welding depth L were measured.

Inventive Example As shown in FIG. 1A, a terminal portion of a lead storage battery was formed by using a lead pole 3 and a lead bushing 2. The outer diameter of the lead pole 3 is 38 mm, the outer diameter of the portion including the protrusion 4 is 43 mm, and the inner diameter of the lead bushing 2 is 43.5 mm at the smallest portion corresponding to the protrusion 4. The length of the flat portion (the portion having a constant diameter) of the protrusion 4 is 6.5 mm, and the tapered portions 4a and 4b are formed at an angle of 20 ° up and down from the flat portion. The first tapered portion 2a of the lead bushing 2 had the same inclination of 20 ° as the tapered portion 4a. The second tapered portion 2b provided in the lead bushing 2 was inclined at 10 °. A gas burner flame was supplied to the space 5 formed by the lead bushing 2 and the lead pole 3 to weld them together.

According to such a configuration, a gap of 2.5 mm or more is formed between the lead pole 3 and the lead bushing 2 immediately below the joint.

Comparative Example As shown in FIG. 2A, the lead pole 30 and the lead bushing 2
0 was welded to produce a terminal portion of the lead storage battery. Lead pole 3
The outer diameter of the portion inserted through the lead bushing 20 is 38 m.
m and kept constant. The lead bushing 20 is also shown in FIG.
A first tapered portion 20a similar to that shown in FIG.
Is formed. The minimum inner diameter of the lead bushing 20 is 38.5 mm. In such a configuration of the comparative example, the gap immediately below the joint between the lead bushing 20 and the lead pole 30 after welding is 0.05 to 0.5 mm.

Table 1 shows the measurement results (assuming that the number of measurement points is 100) of the junction depth L of the terminal portion and the incidence of dripping lead from the junction portion in the present invention example and the comparative example.

[0024]

[Table 1]

As shown in Table 1, the structure of the present invention can be configured to have a larger junction depth and less variation than the structure of the comparative example. This is because the gas burner flame can be directly supplied to the deep joint by the projection provided on the lead pole, so that the welding depth L can be formed large.

Next, a lead-acid battery having the above-described terminal portion of the present invention and the terminal portion of the comparative example on the negative electrode was manufactured.

As shown in Table 2, these lead-acid batteries have a constant electrode plate width of 150 mm, change the electrode plate length, and limit the negative electrode absorption to a state where almost no electrolyte is released from the electrode plate group. The formula and a liquid type lead-acid battery in which the electrode plates are all immersed in the electrolytic solution were constructed. These lead-acid batteries have a nominal voltage of 2 V and a rated capacity of 100 hours per hour. Since the active material utilization rate differs due to the difference in electrode plate size or the difference in battery configuration such as liquid type and negative electrode absorption type,
The storage batteries were configured such that all storage batteries had the same capacity by adjusting the number of electrode plate groups and the amount of active material charged per sheet.

[0028]

[Table 2]

The batteries shown in Table 2 were subjected to a charge / discharge cycle at 60 ° C. 2.3V constant voltage, maximum current 40
After the battery was continuously charged at A for one week, the state of the negative electrode terminal portion was observed after eight charge / discharge cycles of 10 A discharge (discharge end voltage 1.75 V). Table 3 shows the results.

[0030]

[Table 3]

As shown in Table 3, according to the structure of the present invention, even if corrosive deposits are generated between the lead pole and the lead bushing, the gap is secured between the lead pole and the lead bushing, so that the corrosion is prevented. It is possible to suppress the occurrence of cracks in the joint due to the deposits. Further, as can be seen from Table 3, if the distance between the lead pole and the lead bushing is secured, the progress of corrosion itself can be suppressed, so that the distance between the lead pole and the lead bushing is secured, and furthermore, the depth of the joint is increased. In addition, combined with the fact that a larger size can be secured, the occurrence of cracks at the joint can be significantly suppressed.

Further, in a closed type structure in which the amount of the electrolytic solution is limited, especially when the aspect ratio (height / width ratio) of the electrode plate is 1.5 or more, the amount of corrosive deposits is large (thickness Is thick). This change in the amount of corrosion deposits is presumed to be due to the sulfuric acid concentration in the electrolytic solution attached to the upper part of the electrode plate group. In particular, in the case of the vertical configuration, it is presumed that the concentration of sulfuric acid in the electrolyte solution corresponding to the upper part of the electrode group was stratified and decreased, thereby promoting corrosion.

Therefore, it is most preferable to apply the structure of the present invention to a sealed lead-acid battery having such a shape that the aspect ratio (height / width ratio) of the electrode plate is 1.5 or more.

[0034]

As described above, according to the structure of the present invention, in a lead-acid battery having a terminal portion in which a lead pole is inserted into a lead bushing and both are welded, the lead bushing and the lead pole And the depth of the joint between them can be secured, and dripping lead during welding can be suppressed. In particular, if the present invention is applied to the negative electrode, it has a remarkable effect that it is possible to suppress corrosion that proceeds on the lead pole and to suppress the occurrence of cracks at the lead bushing-lead pole joint due to this corrosion. It is extremely useful industrially.

[Brief description of the drawings]

FIG. 1 is a sectional view of a terminal welding portion according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of a terminal welding portion of a comparative example.

[Explanation of symbols]

 1,10 Battery case cover 2,20 Lead bushing 2a, 20a First taper part 2b, 20b Second taper part 3,30 Lead pole 4 Projection part 4a, 4b Taper part 5,6 Space 7,60 Joint part

Claims (6)

[Claims] 1. A lead storage battery in which a lead bushing provided on a battery case lid and a lead pole inserted into the lead bushing are joined, wherein a protrusion is provided on an outer periphery of the lead pole, and the protrusion is provided. A lead storage battery, wherein a portion and an inner wall of the lead bushing are joined. 2. When the lead bushing and the lead pole are inserted, the inner diameter of the lead bushing corresponding to the protrusion on the inner wall of the lead bushing is R, which is higher than the portion corresponding to the protrusion. claims the lead bushing inside diameter and characterized in that a R _U, R> the lead bushing inner diameter at lower than a portion corresponding to the protrusion in the case of the _{R L R L, R> R} U in 2. The lead storage battery according to 1. 3. The lead bushing corresponds to a first tapered portion in which the inner diameter of the lead bushing increases as going upward from a portion of the inner wall of the lead bushing corresponding to the protrusion, and a protrusion of the inner wall of the lead bushing. 3. The lead-acid battery according to claim 2, wherein a second tapered portion is provided in which the inner diameter of the lead bushing increases as going downward from the portion. 4. The lead-acid battery according to claim 1, wherein the negative electrode absorbs oxygen gas generated inside the battery case with almost no electrolytic solution released from the electrode plate group. 5. The lead-acid battery according to claim 1, wherein the electrode group is exposed from the surface of the electrolyte so that oxygen gas generated inside the battery case is absorbed by the negative electrode. 6. The lead-acid battery according to claim 4, wherein a ratio of a height dimension to a width dimension of the electrode plates constituting the electrode plate group exceeds 1.5.