JP2006079951A - Lead-acid storage battery grid body and lead alloy for it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lead-acid storage battery grid body capable of enhancing its mechanical strength, and either shortening the time required for a curing process or dispensing with it, and a lead alloy used for the lead-acid battery. <P>SOLUTION: In this lead-acid storage battery grid body using the lead alloy, the lead alloy contains ytterbium of 0.05-1% by mass% (it is to be repeated in the following). In addition, the lead alloy may contain calcium of 0.10% or less, tin of 0.3-2.0%, and aluminum of 0.01-0.05% as required, together with ytterbium. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a lead storage battery grid and a lead alloy used for the lead storage battery grid, and more particularly to a lead storage battery grid with improved mechanical strength and a lead alloy used for the lead storage battery grid.

Conventionally, as lead alloys for lead-acid battery grids, since mechanical strength is mainly emphasized, alloys containing a large amount of Sb of 4.5 to 8.0% by weight have been used.
However, when this lead alloy is applied to a lead-acid battery grid, it promotes self-discharge of the battery due to the above Sb, and not only lowers the capacity, but also severe water decomposition in a fully charged or overcharged state A reaction took place requiring water replenishment.

Therefore, Pb-Ca-Sn alloys or Pb-Ca-Sn-Al alloys not containing Sb have been proposed as lead alloys for lead-acid battery grids without the above-mentioned drawbacks, and the corrosion resistance and mechanical strength of these alloys are proposed. In order to improve the above, a technology has been developed to add lead alloys for lead-acid battery grids by adding Ba-Ag, Mg, Bi-Ag, Ba-Bi, Ba-Ce, In, etc. (for example, patents) Literature 1-7).
JP 2002-134116 A JP 2002-194463 A JP 2002-329499 A JP 2003-151562 A JP 2003-151563 A JP 2003-221633 A Japanese Patent Laid-Open No. 2001-23662

  In Patent Documents 1 and 2, “0.04 to 0.10% by weight of calcium, 0.80 to 2.00% by weight of tin, 0.01 to 0.03% by weight of aluminum, and 0.01% of silver ~ 0.10% by weight, barium is 0.001 ~ 0.015% by weight, and the balance is lead-based alloy for lead-acid batteries consisting of lead. "And" Calcium is 0.04 ~ 0.10% by weight, tin is 0% .50 to 2.00% by weight, aluminum is more than 0.04% by weight and 0.06% by weight or less, barium is 0.001 to 0.015% by weight, silver is 0.01 to 0.10% by weight, These lead-based alloys for lead-acid batteries, the balance of which is made of lead, are described, and the inventions of these lead-based alloys for lead-acid batteries are suitable for continuous casting and gravity casting because the castability is maintained at a problem-free level. In addition, a decrease in elongation, an improvement in 0.2% proof stress, and a large amount of corrosion weight loss As a result of this reduction, it is possible to expect a further improvement in life as compared with a lead storage battery using a conventional lead-based alloy as a substrate (Patent Document 1, Paragraph [0027], Patent Document 2, Paragraph [0026]). However, the effect of improving mechanical strength is not recognized in silver, and barium can be added only up to 0.015% by weight in relation to corrosion resistance and castability. The improvement was limited. Furthermore, when barium is added and age hardened, the strength is improved, but it has been necessary to stand at a temperature of 60 to 70 ° C. for 2 to 3 days.

  Patent Document 3 states that “0.04 to 0.10% by weight of calcium, 0.80 to 2.00% by weight of tin, 0.01 to 0.03% by weight of aluminum, and 0.0005 to 0 of magnesium. .05% by weight, the balance being lead-based alloy for lead-acid battery. The invention of the lead-based battery for lead-acid battery is “continuous casting and gravity while maintaining castability at a good level”. In addition to being suitable for casting, it has become possible to reduce elongation, increase maximum tensile strength, and reduce 0.2% yield strength at high temperatures for a long time. As a result of improvements in corrosion resistance and reduction in corrosion weight, the life expectancy can be further improved compared to lead-acid batteries using conventional lead-based alloys for the substrate, and the aging period can be shortened by showing high mechanical strength from the beginning of aging. Increase production efficiency Rukoto can. "But in which an effect that (paragraph [0019]), with the addition of magnesium, improvement of mechanical strength is not sufficient.

  Patent Document 4 states that “a calcium content is 0.03 to 0.10% by weight, a tin content is 0.60 to 2.00% by weight, an aluminum content is 0.01 to 0.03% by weight, silver A lead-based alloy for a lead storage battery having a content of 0.005 to 0.10% by weight, a bismuth content of 0.05 to 0.15% by weight, and the balance being made of lead. " The invention of the base alloy “has been expected to further improve the life of the battery by reducing elongation, increasing the maximum tensile strength, improving 0.2% proof stress, and greatly improving the corrosion resistance” (paragraph [ [0018] However, even when bismuth is added, the mechanical strength is not sufficiently improved.

  Patent Document 5 states that “0.03-0.10% by weight of calcium, 0.60-2.00% by weight of tin, 0.01-0.03% by weight of aluminum, and 0.001-0 of barium. .01% by weight, bismuth 0.05-0.15% by weight, and the balance being lead-based alloy for lead-acid batteries, which is composed of lead. " And 0.2% proof stress when over-aged, improved high-temperature creep resistance, and greatly improved corrosion resistance. Compared to conventional lead-acid batteries using lead-based alloys as the substrate, the lattice strength at high temperatures is higher. It has the effect of being able to suppress breakage and gloss due to lack of strength and to expect a further improvement in battery life ”(paragraph [0019]). However, barium and bismuth are used in combination. However, the mechanical strength is not sufficiently improved.

  Patent Document 6 states that “0.04 to 0.10% by weight of calcium, 0.80 to 2.00% by weight of tin, 0.01 to 0.03% by weight of aluminum, cerium or the sum of cerium and barium. Is 0.001 to 0.05% by weight, and the balance is lead-based alloy for lead-acid batteries. The invention of this lead-based alloy for lead-acid batteries states that “castability is maintained at a level at which there is no problem. It is suitable for continuous casting and gravity casting, and has a low elongation, improved maximum tensile strength, low 0.2% proof stress during overaging, and low corrosion weight loss. Therefore, compared to conventional lead-acid batteries using a lead-based alloy as a substrate, there is less risk of lattice breakage due to reduced corrosion and deformation of the lattice and lattice breakage due to intergranular corrosion. Active material adhesion Satisfactory life expectancy at higher temperatures can be expected ”(paragraph [0024]), and“ the inclusion of a combination of cerium and barium significantly improves the aging function immediately after casting. The mechanical strength appears early, the strength is high, and the strength is maintained for a long period of time. ”(Paragraph [0010]). Even in combination, mechanical strength is not sufficiently improved.

  Patent Document 7 states that “in a lead storage battery including a positive electrode lattice body made of a lead-calcium-tin alloy, the lattice body is 0.01-0.1 wt% calcium, 1.0-2.5 wt% tin. In the present invention, the use of a positive electrode grid body with indium added suppresses local corrosion of the grid body and suppresses a decrease in the capacity of the lead storage battery. The lead storage battery having excellent life performance can be provided "(paragraph [0017]), but it is not intended to improve the mechanical strength of the lattice.

  Even if various elements are added to the lead-calcium-tin-based lead alloy or lead-calcium-tin-aluminum-based lead alloy, which is a lead alloy for lead-acid battery grids, the mechanical strength is not sufficiently improved. Moreover, a lead-acid battery lattice body and the lead-acid battery lattice body that can solve the above-mentioned problems of the prior art that require a long time for age-hardening, improve mechanical strength, and shorten or eliminate the time for curing treatment It is an object of the present invention to provide a lead alloy for use in the manufacturing process.

The present inventor is effective in improving the mechanical strength of a lead storage battery grid by including ytterbium (Yb) in a lead alloy such as a known lead-calcium-tin lead alloy used in the lead storage battery grid. The present invention has been found and completed.
That is, the present invention employs the following means in order to solve the above-described problem of improving the mechanical strength of the lead-acid battery grid.
(1) A lead storage battery grid using a lead alloy, wherein the lead alloy contains 0.05 to 1% ytterbium in mass% (hereinafter the same).
(2) The lead storage battery grid according to (1), wherein the lead alloy is a lead-calcium lead alloy, a lead-tin lead alloy, or a lead-calcium-tin lead alloy.
(3) The lead storage battery grid according to (2), wherein the lead alloy contains 0.10% or less of calcium.
(4) The lead storage battery grid according to (2) or (3), wherein the lead alloy contains 0.3 to 2.0% tin.
(5) The lead storage battery grid according to any one of (2) to (4), wherein the lead alloy further contains 0.01 to 0.05% of aluminum.
(6) A lead alloy for lead-acid battery grids containing 0.05 to 1% ytterbium, with the balance being lead and inevitable impurities.
(7) A lead alloy for lead-acid battery grids containing not more than 0.10% calcium and 0.05 to 1% ytterbium, with the balance being composed of lead and inevitable impurities.
(8) A lead alloy for lead-acid battery grids containing 0.3 to 2.0% tin and 0.05 to 1% ytterbium, with the balance being lead and inevitable impurities.
(9) A lead alloy for lead-acid battery grids containing 0.10% or less of calcium, tin of 0.3 to 2.0%, ytterbium of 0.05 to 1%, and the balance consisting of lead and inevitable impurities.
(10) The lead alloy for a lead storage battery grid according to any one of (6) to (9), further containing 0.01 to 0.05% of aluminum.

  According to the present invention, the mechanical strength of the lead-acid battery grid body is improved, and the time for the curing process is shortened or no longer required. Therefore, the manufacturing time of the grid body is shortened and the productivity is improved.

  The present invention is characterized in that ytterbium (Yb) is contained in a known lead alloy for lead-acid battery grids such as lead-calcium-tin-based lead alloys to form a lead-acid battery grid, thereby not containing Yb. Compared with the lead-acid battery grid, the mechanical strength is improved.

The content of Yb is preferably 0.05 to 1%.
If Yb is less than 0.05%, as shown in FIG. 1, the effect of improving the mechanical strength (tensile strength) is not sufficient.
If it exceeds 1%, as shown in FIGS. 1 and 2, the improvement in mechanical strength is saturated, and the elongation gradually decreases. This is presumably because the intermetallic compound Pb ₃ Yb was excessively generated in the alloy and became brittle. Furthermore, Yb is expensive, and if added in a large amount, there is a problem that casting becomes difficult, so 1% or less is preferable.

FIG. 1 and FIG. 2 show a comparison of mechanical strength (tensile strength) and elongation of alloys containing Yb, Mg, Ba, Bi, Ce, Ca, and Sb in Pb.
1 and 2, when Pb contains the same amount of Yb as Mg, the Pb—Yb alloy containing Yb is more Pb—Mg containing Mg in the range where the content is small. It can be seen that the mechanical strength (tensile strength) is higher than that of the alloy and the elongation is good.

  Ba can contain only 0.023 atomic% (0.015 mass%) in Pb (see Patent Documents 1 and 2), but in this range, the Pb—Yb alloy is the Pb—Ba alloy. Greater mechanical strength.

  1 and 2, the Pb—Yb alloy containing Yb in Pb is slightly inferior to the Pb—Bi alloy and Pb—Ce alloy containing Bi and Ce in Pb, but the mechanical strength is low. I can see it's big.

  The Pb—Yb alloy is slightly inferior in elongation to the Pb—Sb alloy, but it can be seen that the mechanical strength is large in the range where the contents of Yb and Sb are small.

  From FIG. 1 and FIG. 2, the Pb—Yb alloy is less than the Pb—Ca alloy containing Ca in mechanical strength (tensile strength) and elongation, but as shown in FIG. Since the crystal grains are finer than (-Sn-Al) alloy and the grain boundary is complicated, it is considered unlikely that the lattice body suddenly breaks and has a lifetime as seen in Pb-Ca alloys. .

In the present invention, Ca is contained to improve mechanical strength (tensile strength), but the content is preferably 0.10% or less.
Since Yb can ensure the tensile strength by containing Ca, Ca that adversely affects the life performance can be prevented from being contained, and even when contained, it can be made 0.10% or less.

Sn is added to improve the flowability and mechanical strength of the alloy, but the content is preferably 0.3 to 2.0%. 0.3 to 1.8% is more preferable.
When Sn is less than 0.3%, the effect is not sufficient, and when it exceeds 2.0%, corrosion resistance is inferior with an increase in Sn content, which is not preferable.

Al is contained as necessary in order to prevent loss of Ca and Yb due to oxidation of the molten metal, but the content is preferably 0.01 to 0.05%.
This is because the effect is not sufficient when the content is less than 0.01%, and the above effect does not appear remarkably when the content exceeds 0.05%.

  Furthermore, in order to improve corrosion resistance and further improve mechanical strength, the lead alloy used in the lead-acid battery grid of the present invention can contain elements other than those described above as necessary.

  In the present invention, the mechanical strength of the lead-acid battery grid body is improved by making the lead alloy into the above composition, and when producing the grid body, the castability is hardly impaired, so that gravity casting or continuous casting is performed. Furthermore, it can be expanded.

  And the lead acid battery using the grid body of the present invention has excellent cycle characteristics because the mechanical strength of the grid body is improved.

Lead alloys containing Ca, Sn, Al, and Yb so as to have the amounts shown in Table 1 were melted at a melting temperature of 470 ° C. and cast at a mold temperature of 170 ° C. to obtain tensile test samples No. 1 to 18 .
Sample shape: Tensile specimen (No. 6 specimen according to JIS Z 2201)

A tensile test was performed under the following conditions to measure the tensile strength of the sample. The measurement results of tensile strength are also shown in Table 1.
Tensile test conditions: Tensile speed 30 mm / min, curing time 25 days, curing temperature room temperature (25 ° C.)

From Table 1, the Pb—Yb alloy lattice (sample Nos. 3 to 5) containing 0.1 to 1% of Yb is the current low Sb (1.85 to 2.5) shown in FIG. It can be seen that it has a tensile strength comparable to that of the lattice body of 45%)-Pb alloy.
When the Yb content is about 0.01% (less than 0.05%) as in sample No. 1, the tensile strength is low, so 0.05% (sample No. 2) or more is preferable. When it is 3% (exceeding 1%) as in sample No. 6, the tensile strength is reduced and the elongation is also reduced.
In addition, the Pb-0.06Ca-1.5Sn alloy is about 450 kgf / cm ² , the Pb-0.09Ca-1.2Sn alloy is about 550 kgf / cm ² (age hardening 25 days), and with the addition of Yb alone, Although the tensile strength (comparative examples 1 and 2) of the current Pb-Ca-Sn alloy is not reached, the tensile strength is increased with the Pb-Ca alloy in order to prevent the lattice body from being stretched by corrosion and to prevent short circuit. If the Ca that causes corrosion of the Pb—Ca alloy can be reduced, it is considered that the tensile strength at the Pb—Ca alloy level is not necessary.
That is, if the Ca content is reduced, the tensile strength is lowered, but Ca that causes corrosion can be reduced. Therefore, the Pb—Yb alloy of the present invention is actually used as the Pb— shown in FIG. Those having the same level of tensile strength as the Sb alloy are sufficient.
Ca can be added as necessary, and it can be seen that when 0.01 to 0.09% of Ca is contained together with Yb, the tensile strength is improved (Sample Nos. 7 to 11).
Furthermore, when Sn is contained in an amount of 0.3 to 2.0%, the tensile strength is improved (Sample Nos. 13 to 18).

  In the examples, Al was added in an amount of 0.02% to prevent the oxidation loss of Ca and Yb. However, since Al does not affect the tensile strength, a Pb—Yb alloy without addition of Al, Pb— Ca-Yb alloy, Pb-Sn-Yb alloy, and Pb-Ca-Sn-Yb alloy also have the effect of improving tensile strength.

It is a comparison figure of the tensile strength of the alloy which made Pb contain various elements. It is a comparison figure of the elongation of the alloy which made Pb contain various elements. It is a comparison figure of the solidification structure (crystal grain) of the alloy which made Pb contain various elements.

Claims (10)

  A lead-acid battery grid using a lead alloy, wherein the lead alloy contains 0.05 to 1% ytterbium in mass% (hereinafter the same).   The lead storage battery grid according to claim 1, wherein the lead alloy is a lead-calcium-based lead alloy, a lead-tin-based lead alloy, or a lead-calcium-tin-based lead alloy.   The lead storage battery grid according to claim 2, wherein the lead alloy contains 0.10% or less of calcium.   The lead storage battery grid according to claim 2 or 3, wherein the lead alloy contains 0.3 to 2.0% of tin.   The lead storage battery grid according to any one of claims 2 to 4, wherein the lead alloy further contains 0.01 to 0.05% of aluminum.   A lead alloy for lead-acid battery grids, containing 0.05 to 1% ytterbium, with the balance being lead and inevitable impurities.   A lead alloy for lead-acid battery grids containing 0.10% or less calcium, 0.05 to 1% ytterbium, and the balance being lead and inevitable impurities.   A lead alloy for lead-acid battery grids containing 0.3 to 2.0% tin and 0.05 to 1% ytterbium, with the balance being lead and inevitable impurities.   A lead alloy for lead-acid battery grids containing 0.10% or less of calcium, 0.3 to 2.0% of tin, 0.05 to 1% of ytterbium, and the balance consisting of lead and inevitable impurities. Furthermore, the lead alloy for lead acid battery lattice bodies as described in any one of Claims 6-9 containing 0.01 to 0.05% of aluminum.

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