JP2002175798A - Sealed lead-acid battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a highly reliable and long-life sealed lead-acid battery whose positive electrode grid and positive and negative straps are all excellent in the corrosion resistance. SOLUTION: In the sealed lead-acid battery, a lead (Pb)-Ca-Sn alloy comprising 0.025-0.065 mass % of calcium(Ca) and 0.25-1.0 mass % of tin(Sn) is used as the negative electrode grid, and a Pb-Sn alloy comprising 1.3 mass % or less of pure lead or Sn is used as the added lead to form the straps for connecting lug parts of electrode plates.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a sealed lead-acid battery.

[0002]

2. Description of the Related Art A closed lead storage battery utilizing a so-called oxygen cycle in which oxygen gas generated during charging of a battery is absorbed by a negative electrode plate, a method called a retainer type is currently generally employed. Retainer-type sealed lead-acid battery is a sulfuric acid electrolyte required for charging and discharging batteries in a mat-shaped separator (hereinafter referred to as a glass separator) mainly composed of a positive electrode plate, a negative electrode plate, and fine glass fibers inserted between them. , No excess flowing electrolyte, and both electrodes are separated by a glass separator.

[0003] The sealed lead-acid battery is used as a portable power source, a backup power source for a computer, and the like by utilizing features such as no maintenance, no liquid leakage, and position free.

[0004] Pb-Ca alloys are widely used as current collectors (grids) in these sealed lead-acid batteries in order to suppress self-discharge and decrease in electrolyte and to make maintenance free. In addition, pure lead or Pb-Sn based alloy not containing antimony (Sb) is usually used as an additional lead for forming a strap connecting the ears of the lattice body.

[0005]

In order to increase the mechanical strength of the lattice, the Ca content is 0.07 to 0.12% by weight (mass)%.
When added, Ca is easily oxidized, so that the corrosion resistance of the welded portion between the ear and the strap is reduced, and also as to prevent the mechanical strength of the welded portion between the ear and the strap from being reduced. JP-A-6-196145 proposes to reduce the amount of Ca in the lattice and use a Pb-Sn alloy containing 1.0 to 5.0% by mass of Sn as a lead for forming a strap. JP-A-6-196145
Then, it is not specified whether the corrosion resistance is reduced by the positive electrode strap or the negative electrode strap.

[0006]

[Problems to be Solved] Ca is contained in an amount of about 0.07 to 12% by weight in order to improve the mechanical strength of the grid or the electrode plate. And this Ca
However, since the corrosion resistance is easily oxidized and corroded, when the content of Ca in the lattice increases, there arises a problem that the corrosion resistance of the welded portion between the ear portion and the strap of the lattice decreases. Regarding whether the closed type without the flowing electrolyte or the open type with the flowing electrolyte, it is generally considered that the grid of the lead storage battery is oxidized and corroded by the positive electrode, It is considered that what is recognized as a problem to be solved in the gazette is a positive electrode strap.

Further, in the first column of the patent publication,

[0008]

2. Description of the Related Art Lead-calcium-tin (Pb), which is effective for maintenance-free operation, is capable of suppressing a decrease in the amount of electrolyte and is provided on the positive and negative grids of a sealed lead-acid battery. The strap connecting the ears has a
As disclosed in Japanese Patent No. 25895, pure lead or a lead alloy containing no antimony (Sb) is used.

[0009]

Since the Ca is easily oxidized and corroded, if the content of Ca in the lattice increases, the welded portion between the ears of the lattice and the straps may be damaged.
If the alloy composition of the lead alloy that does not contain Sb that constitutes the strap is appropriately selected with respect to the alloy composition of the Pb—Ca—Sn alloy that constitutes the expanded lattice, the weldability between the alloys is reduced, The present invention solves such a problem, and the present invention solves such a problem. "(Omitted)" is described in Japanese Patent Application Publication No. 3-25895. In the first and second columns of the publication, “Detailed description of the invention, Industrial application field (omitted)) However, the lead storage battery having the above structure has the following disadvantages.
Since an electrode using a grid made of a lead-calcium alloy (binary alloy) is used, the electrode has poor corrosion resistance and a short cycle life. (2) Since poles or terminals made of a lead-antimony alloy (binary alloy) are used, the strength of the poles or terminals is not sufficient. SUMMARY OF THE INVENTION The object of the present invention is to solve the above-mentioned drawbacks and to provide a lead-acid battery in which the corrosion resistance of the electrode plate is improved and the strength of the poles or terminals is further improved. According to the present invention, there is provided an electrode plate 2, an electrode pole 3 or a terminal 7, and a connection piece 4, wherein the electrode plate 2
Is a lattice body made of a lead-calcium-tin alloy, and the connection piece 4 is made of pure lead or a lead alloy not containing antimony. 3 or the terminal 7 is connected. Therefore, the fact that the corrosion resistance of the electrode plate may be poor depending on the alloy composition should be solved in Japanese Patent Publication No. 3-25895, considering that this is a theme of the positive electrode plate in the lead storage battery. It is clear that what is recognized as a problem is the positive electrode, and therefore, the object of improving corrosion resistance, which is recognized as a problem to be solved in JP-A-6-196145, is also a positive electrode strap. It is.

However, when these sealed lead-acid batteries are used for a long period of time, in addition to those that can be used without any problem up to the expected life, those whose life is extended due to corrosion of the positive electrode grid,
The positive electrode or negative electrode strap was corroded, and some of them reached their end of life. As a result of intensive investigation and research on these causes, it was found that the causes of these corrosions were the lattice alloy composition and Sn in the lead alloy.

The present invention solves the above-mentioned problems, and uses a Pb-Ca-Sn-based alloy excellent in corrosion resistance for a positive electrode grid and an economical Pb-Ca-Sn-based alloy for a negative electrode. At the same time as using the strap, a lead alloy for forming a strap is added to the ears of the strap, thereby improving the corrosion resistance of the welded portion between the ear and the strap, and the corrosion resistance of the strap body. All have excellent corrosion resistance, and together with these effects, provide a highly reliable and long life sealed lead-acid battery.

Generally, in a lead storage battery, the negative electrode becomes metallic lead when charged, and should not be corroded. However, as described above, the sealed lead-acid battery has no excess flowing electrolyte, and the electrolyte required for charging and discharging is held by the positive and negative plates and the glass separator. Although in contact, both the positive and negative straps are remote from the electrolyte surface. For this reason, these straps are slightly wetted with the electrolytic solution, but are not sufficiently supplied with the electrolytic solution. In such a case, it is considered that the negative electrode strap is corroded by the oxygen gas generated in the positive electrode. It is considered that the corroded negative electrode strap is not reduced to metallic lead and corrosion proceeds because there is not enough electrolyte solution in the surroundings even after charging.

[0013]

In order to solve the above-mentioned problems, a sealed lead-acid battery according to the first aspect of the present invention has a negative electrode grid containing calcium (Ca) in an amount of 0.025 to 0.06.
A lead (Pb) -Ca-Sn-based alloy containing 5% by mass and 0.25 to 1.0% by mass of tin (Sn) is used, and pure lead is used as a lead for forming a strap for connecting the electrode plate ears. A Pb-Sn alloy containing 1.3 mass% or less of lead or Sn is used.

According to a second aspect of the present invention, there is provided the sealed lead-acid battery according to the first aspect, wherein Ca is added to the positive electrode grid by 0.0%.
25 to 0.065% by mass, Sn: 1.1 to 2.0% by mass
Containing a Pb-Ca-Sn-based alloy.

According to a third aspect of the present invention, in the sealed lead-acid battery according to the first or second aspect, the positive electrode grid and / or
Or, the negative electrode grid contains aluminum (Al) in a range of 0.003 to
It contains 0.03% by mass.

According to a fourth aspect of the present invention, in the sealed lead-acid battery according to the second or third aspect, the positive electrode grid is made of silver (A).
g) in an amount of 0.03 to 0.09% by mass.

The invention according to claim 5 is the invention according to claims 1, 2,
3. The sealed lead-acid battery according to 3 or 4, wherein the positive electrode grid and / or the negative electrode grid are obtained by expanding or punching a rolled sheet or a cast sheet.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention uses an economical Pb-Ca-Sn-based alloy with a small amount of Sn for the negative electrode grid, at the same time reduces the amount of Ca in the grid and adds pure lead to the lead. Alternatively, since a Pb-Sn alloy with a small amount of Sn is used, the corrosion resistance of the strap, particularly the welded portion between the ear and the strap, is improved, and the corrosion resistance of the strap main body is also improved, resulting in a reliable long life. Can be provided.

The amount of Ca in the negative electrode lattice alloy is desirably 0.065% by mass or less to suppress corrosion in the strap, but is desirably 0.025% by mass or more from the viewpoint of lattice strength.

The negative grid does not require as much corrosion resistance as the positive grid during use of the battery.
Although the amount is not necessary, if the amount is too small, the strength is reduced and the handleability during the battery manufacturing process is deteriorated. The upper limit is
From an economic viewpoint, it is desirable that the amount is small as long as there is no problem in handling properties, and usually it is preferably 1.0% by mass or less.

On the other hand, a Pb-Ca-Sn-based alloy having excellent corrosion resistance and a slightly increased Sn content is used for the positive electrode grid to extend the life of the electrode plate. The amount of Ca in the positive electrode lattice alloy is desirably 0.065% by mass or less to suppress corrosion in the strap, but from the viewpoint of lattice strength, 0.025% by mass is preferable.
The above is desirable.

The amount of Sn in the positive electrode grid alloy is 1.1% by mass from the viewpoint of the corrosion resistance and strength of the positive electrode grid during use of the battery.
The above is desirable, but if it is more than 2.0 mass%, not only corrosion resistance is inferior but also uneconomical in terms of cost,
1.1 to 2.0% by mass is appropriate.

When a Pb-Ca-Sn alloy grid is manufactured by gravity casting, or when a grid is manufactured by an expanding method or a punching method, a slab (flat plate) for a rolled sheet is cast or a cast sheet is manufactured. At this time, 0.003 to 0.03% by mass of Al is added to prevent oxidation of Ca and stabilize the amount of Ca. If this method is used, it is not necessary to use an inert gas such as an argon gas to prevent the oxidation of Ca, and the workability is good and economical.

Here, the cast sheet is also called a DM sheet, and is obtained by slightly immersing a rotating roll in a molten lead alloy to form a sheet directly on the roll surface.

In recent years, the temperature of the environment in which lead-acid batteries are used has been increasing, and in order to improve the durability of the positive electrode grid at such high temperatures, Ag is added to the positive electrode grid in an amount of 0.02 to 0.02. It is effective to add 0.09% by mass,
A more reliable and long-life lead-acid battery can be obtained by using the above-described strap together.

Further, the Pb-Ca-Sn-based alloy lattices include not only lattices produced by a conventional gravity casting method but also Pb-Ca-Sn-based alloy lattices whose production volume has been increasing in recent years. It is also possible to use a grid produced by expanding or stamping a rolled alloy sheet or a cast sheet. In these methods, the production speed is higher than in the conventional gravity casting method, and the grid can be manufactured economically.

[0027]

Embodiments of the present invention will be described below. (Example 1) A rolled sheet using a Pb-Ca-Sn-based alloy in which the amounts of Ca and Sn were changed as shown in Table 1 was prepared.
It was expanded to obtain a positive electrode grid. In addition,
In order to prevent oxidation during casting of the slab for rolling, 0.01% by mass of Al was added in each case.

[0028]

[Table 1]

Next, these grids are filled with a positive electrode paste according to a conventional method, aged and dried.
Sheets, 5 negative plates and a glass separator,
Heating and welding were performed with a gas burner to form a strap, and liquid injection and formation were performed to obtain a 12 V, 50 Ah, closed-type lead storage battery of a retainer type. As shown in Table 1, pure lead (without Sn addition) and Sn contained in the strap alloy were 0.8 to 5.0% by mass.
Pb-Sn alloy was used.

The negative electrodes of these batteries were provided with No. Using a grid of No. 4, a negative electrode paste was filled in accordance with a conventional method, and aged and dried.

Next, these batteries were placed in a 60 ° C. air bath for 1 hour.
A continuous overcharge test was performed for 6 months at a constant voltage of 3.38 V, and the corrosion state of the positive electrode grid and the corrosion state of the positive electrode strap after the test were observed.

Table 2 shows the corrosion states of the positive electrode grid and the positive electrode strap after the overcharge test.

[0033]

[Table 2]

In a lead storage battery, corrosion of the positive electrode member is inevitable. However, as is apparent from Table 2, particularly when the amount of Sn in the positive electrode grid is 0.70% by mass, overcharging occurs. The corrosion of the positive electrode grid after the test was severe. However, S
When the amount of n was 1.10% by mass and the amount of Ca was 0.065% by mass or less, the amount of corrosion was small, and the level was practically acceptable. Further, the amount of Sn was increased to 1.50 and 2.0.
When the content was 0% by mass, the corrosion of the positive electrode grid was further reduced.

Further, the amount of Ca in the positive electrode lattice is set to 0.020 to
When the content was 0.065% by mass or less, almost no corrosion was observed in the positive electrode strap (near the welded portion with the ear) even after the overcharge test.

When pure lead is used as the added lead and when Sn is 0.
When the content was 8% by mass or less, almost no corrosion of the positive electrode strap main body was observed. In addition, Pb-1.
In the case of using 0 mass% Sn and Pb-1.3 mass% Sn, corrosion was slightly observed. However, Pb-2.0 mass% Sn and Pb-5.
In the case of using 0 mass% Sn, slightly more severe corrosion was observed than in the case where Sn was 1.3 mass% or less.

When the amount of Ca in the positive electrode grid is 0.020% by mass, the lattice strength is low, the handling property in battery production is poor, and the electrode plate elongation after the overcharge test is 0.025% by mass.
It was slightly larger than that of ０．０0.065 mass%. (Example 2) A rolled sheet using a Pb-Ca-Sn-based alloy in which the amounts of Ca and Sn were changed as shown in Table 3 was produced and expanded to obtain a negative electrode grid.

[0038]

[Table 3]

Next, these grids are filled with a negative electrode paste according to a conventional method, aged and dried.
Sheets, 5 negative plates and a glass separator,
Heating and welding were performed with a gas burner to form a strap, and liquid injection and formation were performed to obtain a 12 V, 50 Ah, closed-type lead storage battery of a retainer type. As shown in Table 3, pure lead (without Sn addition) and Sn contained in the strap alloy were 0.8 to 5.0% by mass.
Pb-Sn alloy was used.

The positive plates of these batteries were provided with Nos. Using 14 grids, a positive electrode paste was filled according to a conventional method, and aged and dried.

Next, these batteries were used in the same manner as in Example 1,
A continuous overcharge test was performed for 6 months at a constant voltage of 13.38 V in a 0 ° C. air bath, and the corrosion state of the negative electrode strap after the test was observed.

Table 4 shows the corrosion state of the negative electrode strap after the overcharge test.

[0043]

[Table 4]

As is clear from Table 4, C in the negative electrode lattice
When the amount of a was 0.020 to 0.065% by mass or less, almost no corrosion was observed in the negative electrode strap (near the welded portion with the ear) even after the overcharge test.

[0045] Pure lead was used as the added lead, and Sn was added in an amount of 0.
When the content was 8% by mass or less, almost no corrosion of the negative electrode strap body was observed. In addition, Pb-1.
In the case of using 0 mass% Sn and Pb-1.3 mass% Sn, corrosion was slightly observed. However, Pb-2.0 mass% Sn and Pb-5.
In the case of using 0% by mass of Sn, it was observed that as the amount of Sn increased, corrosion increased.

When the amount of Ca in the negative electrode grid was set to 0.02% by mass, the grid strength was low and the handleability in battery production was poor. (Example 3) A positive electrode grid was obtained by gravity casting using a Pb-Ca-Sn-Ag-based alloy in which the amount of Ag was changed as shown in Table 5, column A. The amounts of Ca and Sn were set to 0.03% by mass and 1.1% by mass, respectively.
01% by mass was added.

Next, these grids are filled with a positive electrode paste according to a conventional method, aged and dried.
Sheets, 5 negative plates and a lath separator, heat and weld with a gas burner to form a strap,
A 12 V, 50 Ah retainer-type sealed lead storage battery was obtained. Pure lead was used for the strap alloy.

It should be noted that Pb-
A gravity-cast grid made of 0.065% by mass Ca-0.7% by mass Sn-0.01% by mass Al alloy was used, and a negative electrode paste was filled according to a conventional method, and aged and dried.

Next, these batteries were tested in the same manner as in Example 1, the corrosion state of the positive electrode grid after the test was observed, and the elongation (vertical direction) of the positive electrode grid was measured.

The corrosion state of the positive electrode grid after the overcharge test and the longitudinal elongation of the positive electrode grid are shown in Tables 5, B and C, respectively.

[0051]

[Table 5]

As is apparent from Table 5, the Ag content was 0.02.
In the case of containing Ag by mass or more, the corrosion of the lattice is further reduced and the longitudinal elongation of the lattice is also reduced by about 1 / compared to the case of not containing Ag or containing 0.01% by mass of Ag.
2 or less. Even if Ag is added in an amount of more than 0.09% by mass, the corrosion resistance of the positive electrode grid is not so different from that in the case where 0.09% by mass is added. Then, Ag is eluted from the positive electrode grid, deposited on the negative electrode plate, and the hydrogen overvoltage is reduced, self-discharge increases, and the characteristics as a sealed lead-acid battery deteriorate.

The positive and negative electrode straps (near the welded portion to the ear and the strap body) hardly corroded in any of the batteries.

In Examples 1 to 3, welding was carried out with a gas burner. However, molten lead was poured into a mold in which the shape of the strap was engraved, an ear was placed therein, and then the lead was cooled and solidified to cool the solid. A similar effect can be obtained by a welding method called a cast-on-strap in which the strap is formed at the same time as the part and the lead are welded.

When pure lead is used as the additional lead,
Although its mechanical strength is slightly lower than that in the case of adding Sn, it can be used without any problem by devising the thickness and shape of the strap.

Further, the positive electrode lattice and / or the negative electrode lattice are engraved with a grid shape on a rotating roll, and a shoe is pressed against the rotating roll from the outside. A molten lead alloy is interposed between the engraved grid-shaped groove and the pressed shoe. Can be press-fitted and solidified while rotating (continuous casting method), or a grid obtained by rolling this can be used.

The positive / negative electrode grid and the additional lead contain about 0.05% by mass of bismuth, which is said to be effective for improving battery performance when used for a sealed lead-acid battery. Alternatively, the above-mentioned effect is not changed at all even if unavoidable impurities at a level permitted for a sealed lead-acid battery are contained.

[0058]

As described above, according to the present invention, a Pb-Ca-Sn-based alloy having excellent corrosion resistance is used for the positive electrode grid, the life of the electrode plate is extended, and the economical Pb-Pb is used for the negative electrode. -C
a-Sn based alloy, and at the same time, C
Since the amount of a is reduced and pure lead or a Pb-Sn alloy having a Sn content of 1.3% by mass or less is used as the additional lead, the corrosion resistance of the strap, especially the welded portion between the ear and the strap is used. To improve the corrosion resistance of the strap body, and to provide a highly reliable, long-life sealed lead-acid battery with both the positive grid and the positive and negative straps having excellent corrosion resistance. Can be.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01M 10/12 H01M 10/12 Z F-term (Reference) 5H017 AA01 AS02 AS10 BB00 BB02 BB06 BB07 CC05 EE03 HH01 5H022 AA02 BB11 CC15 CC20 CC23 CC30 EE02 KK07 5H028 AA01 CC05 CC07 CC08 EE01 FF04 FF05

Claims (5)

[Claims] 1. A method in which calcium (Ca) is added to a negative electrode grid in a concentration of 0.1%.
025 to 0.065 mass%, tin (Sn) 0.25 to
A lead (Pb) -Ca-Sn-based alloy containing 1.0% by mass, and pure lead or Pb containing 1.3% by mass or less of Sn as additional lead for forming a strap for connecting electrode lugs. -A sealed lead-acid battery using an Sn alloy. 2. The cathode grid contains Ca in an amount of 0.025 to 0.02.
Pb-C containing 65% by mass and 1.1 to 2.0% by mass of Sn
The sealed lead-acid battery according to claim 1, wherein an a-Sn-based alloy is used. 3. The sealed lead-acid battery according to claim 1, wherein the negative electrode grid and / or the positive electrode grid contain 0.003 to 0.03% by mass of aluminum (Al). 4. The positive electrode grid contains silver (Ag) in an amount of 0.02 to 0.02.
4. The composition according to claim 2, wherein the content is 0.09% by mass.
A sealed lead-acid battery according to claim 1. 5. The sealed lead-acid battery according to claim 1, wherein the positive electrode grid and / or the negative electrode grid are grids obtained by expanding or stamping a rolled sheet or a cast sheet. .