JP2006210210A - Lead-acid battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress corrosion generating on a negative electrode ledge side in a welding part of a connecting member such as a connector or a pole and the negative electrode ledge in a negative electrode ledge welding part of a lead-acid battery. <P>SOLUTION: The lead-acid battery comprises the negative electrode ledge 26 combining a positive plate 22 and a negative plate 23 through a separator 24 and gathering and welding negative electrode lugs 23c taken out of the negative plates, and the connecting member 27 joined to the negative electrode ledge, and the joining part of the negative electrode ledge and the connecting member is immersed in an electrolyte. The negative electrode lug is made of Pb-Ca alloy containing no Sb, the connecting member is made of Pb-Sb alloy, and the negative electrode ledge is made of Pb-Sn-Se alloy containing no Sb. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a lead-acid battery.

  As shown in FIG. 1, a positive electrode plate 11 and a negative electrode plate 12 are combined through a separator 13 as a structure of an electrode plate group of a lead storage battery, particularly a lead storage battery used for starting an automobile engine. The positive electrode ear 11a derived from the negative electrode plate 12 and the negative electrode ear 12a derived from the negative electrode plate 12 are collectively welded by the positive electrode shelf 14 and the negative electrode shelf 15, respectively, and the adjacent cells are connected to the positive electrode shelf 14 and the negative electrode shelf 15, respectively. A connecting member 17 such as an inter-cell connecting body for connecting the cell and a pole column for connecting the cell and the terminal 16 provided outside the battery is joined.

  Here, the negative electrode plate has a configuration in which the negative electrode active body 12c is filled in the negative electrode lattice 12b, and the negative electrode ear 12a is integrally formed on the negative electrode lattice 12b. Therefore, the negative electrode grid 12b and the negative electrode ear 12a are made of the same lead alloy.

  Conventionally, a Pb-Sb alloy containing 2.0 to 4.0% by mass of Sb as an alloy used for a shelf or a connection member of a lead storage battery has been widely used because of its excellent strength and weldability. Yes.

  On the other hand, Sb in the Pb—Sb alloy decreases the hydrogen overvoltage of the negative electrode plate, increases the self-discharge amount of the lead storage battery, and promotes the reduction of moisture in the electrolytic solution. Therefore, lead alloys containing no Sb have been used as the negative electrode lattice body for the purpose of suppressing self-discharge and moisture reduction in the electrolyte. As such a lead alloy, a Pb—Ca alloy containing 0.03% by mass to 0.10% by mass of Ca is known and widely used.

When a negative electrode plate using such a Pb—Ca alloy negative electrode grid is jointly welded on the Pb—Sb alloy shelf as described above, the negative electrode ear is provided integrally with the negative electrode grid. Depending on the welding conditions, Ca contained in the negative electrode ear and Sb contained in the negative electrode shelf combine to produce an intermetallic compound of Ca and Sb, such as Ca ₃ Sb ₂ .

  In the case where such an intermetallic compound of Ca and Sb is generated, particularly when the surface of the negative electrode shelf is exposed from the electrolyte solution surface and the pH of the negative electrode shelf surface increases and becomes basic, corrosion proceeds to the negative electrode shelf. In order to suppress the progress of such corrosion, Patent Document 1 discloses a connection member such as a Pb—Ca alloy as a negative electrode lattice, a Pb—Sn alloy as a negative electrode shelf, a connection between cells of a negative electrode, and a negative electrode pole column. It is shown to be formed from an alloy.

  According to the configuration disclosed in Patent Document 1 described above, since Sb is not included in the negative electrode shelf, it is possible to prevent Ca in the negative electrode ear from combining with Sb. On the other hand, with respect to the connection member, a conventional Pb—Sb alloy is used in order to ensure inter-cell welding and terminal welding strength.

  And the production | generation of the intermetallic compound of Ca and Sb in a shelf is suppressed, and the corrosion of the negative electrode shelf generate | occur | produced when a negative electrode shelf is exposed from electrolyte solution is suppressed.

However, even when a Pb—Sn alloy that does not contain Sb is used for the negative electrode shelf, if the battery operating temperature becomes a high temperature exceeding 90 ° C., it is prominent on the negative electrode shelf side of the joint between the negative electrode shelf and the connecting member. Corrosion was observed. Such corrosion causes a decrease in the strength of the joint and a decrease in the discharge voltage during high rate discharge due to an increase in electrical resistance. Unlike the corrosion that occurs when the negative electrode shelf as described above is exposed from the electrolyte, the negative electrode shelf and the joint between the negative electrode shelf and the connecting member are immersed in the electrolyte, that is, the above-described joint is It was a phenomenon that occurred in an acidic state. Corrosion is considered to start from a minute gap generated on the negative electrode shelf side of the joint from its progress state.
Japanese Patent Laid-Open No. 5-13065

  In the present invention, the Pb—Sn alloy is used for the negative electrode shelf and the Pb—Sb alloy is used for the connecting member joined to the negative electrode shelf as described above, and the joint between the negative electrode shelf and the connecting member is immersed in an electrolyte of dilute sulfuric acid. It aims at suppressing the corrosion of the junction part of a negative electrode shelf and a connection member which generate | occur | produces in the lead acid battery.

  In order to solve the above-mentioned problem, a lead storage battery according to claim 1 of the present invention combines a positive electrode plate and a negative electrode plate via a separator, and a negative electrode shelf for collectively welding negative electrode ears derived from the negative electrode plate; A lead storage battery comprising a connecting member bonded to the negative electrode shelf, wherein a joint between the negative electrode shelf and the connecting member is immersed in an electrolyte, wherein the negative electrode ear is made of a Pb-Ca alloy containing no Sb. The connecting member is made of a Pb—Sb alloy, and the negative electrode shelf is made of a Pb—Sn—Se alloy containing no Sb.

  In addition, a connection member means the pole column for connecting the connection body between cells for connecting between adjacent electrode plate groups, and an external terminal and an electrode plate group.

  The Pb—Sb alloy has fine crystal grains, the crystal orientation is uniform in each direction, and the grain boundary rarely grows in one specific direction. On the other hand, Pb—Sn alloy crystals have columnar crystals grown in a direction perpendicular to the cooling surface during solidification, and have a completely different crystal form from Pb—Sb crystals. Thus, it is considered that the corrosion that is the subject of the present invention progresses from this gap as a starting point when a minute gap is generated at the joint portion of the alloys having different crystal forms.

  In the present invention, by adding Se to the Pb—Sn alloy, a fine gap on the negative electrode shelf side of the joint portion between the negative electrode shelf (Pb—Sn—Se alloy) and the connection member (Pb—Sb alloy) is reduced. It is thought that formation can be suppressed and corrosion at this joint can be suppressed.

  With the configuration of the present invention described above, corrosion at the joint between the negative electrode shelf of the lead storage battery and the connecting member can be suppressed, and a lead storage battery excellent in reliability can be provided.

  The lead storage battery according to the embodiment of the present invention combines a positive electrode plate and a negative electrode plate through a separator, and has a negative electrode shelf that collectively welds negative electrode ears derived from the negative electrode plate, and a connecting member joined to the negative electrode shelf. A negative electrode ear is made of a Pb-Ca alloy containing no Sb, and the connecting member is made of a Pb-Sb alloy. The negative electrode shelf is made of a Pb—Sn—Se alloy containing no Sb.

  Here, the Pb—Ca alloy is used to suppress a decrease in hydrogen overvoltage at the negative electrode and an increase in self-discharge amount and liquid reduction amount due to this. Further, the Pb—Sb alloy is used for obtaining weldability and mechanical strength required as a connection member, and both are the premise of the lead storage battery of the present invention. In addition, as for Sb in the Pb—Sb alloy used as the connecting member, the one in the range of 1.0 to 5.0 mass% is used as in the conventional case. Moreover, about 0.1-0.4 mass% of As as a nucleating agent which refines | miniaturizes a crystal grain in Pb-Sb alloy may be included.

  Further, in the present invention, more preferably, the Pb—Sn—Se alloy constituting the negative electrode shelf has Sn of 1.0 to 3.0 mass% and Se of 0.0005 mass% to 0.05 mass%. Including.

  Further, the above lead storage battery of the present invention will be described with reference to the drawings.

  As shown in FIG. 2, the lead storage battery 21 of the present invention has an electrode plate group 25 in which a positive electrode plate 22 and a negative electrode plate 23 are combined through a separator 24. The negative electrode plate 23 has a configuration in which a negative electrode active material 23b for a lead storage battery mainly composed of spongy lead is filled in a negative electrode lattice 23a, and a charging current is input to the negative electrode active material into the negative electrode active material 23a. A negative electrode ear 23c for outputting a discharge current from the active material is integrally provided.

  In the present invention, for the purpose of suppressing a decrease in hydrogen overvoltage of the negative electrode plate, the negative electrode grid body 23a is made of a Pb—Ca alloy containing no Sb, and is provided integrally with the negative electrode grid body 23a. The negative electrode ear 23c is also made of the same Pb—Ca alloy. Ca in the Pb-Ca alloy is added for the purpose of ensuring the mechanical strength of the negative electrode lattice body and the negative electrode ear, and the Ca content concentration in the alloy is in the range of about 0.03% by mass to 0.10% by mass. It is preferable that If the Ca-containing concentration is less than 0.03% by mass, the desired strength cannot be obtained. On the other hand, the addition of Ca exceeding 0.10% by mass reduces the corrosion resistance of the Pb—Ca alloy or, when used as an expanded lattice, the elongation during expansion is not sufficient, and the lattice bone is broken. It may occur and is not preferable.

In addition, when a small amount of Sb is present in the negative electrode grid 23a or the negative electrode ear 23c, the self-discharge characteristics of the lead storage battery are deteriorated, or Ca and Sb contained in the negative electrode grid 23a and the negative electrode ear 23c are combined. Corrosive intermetallic compound (Ca ₃ Sb ₂ ) is generated, and the negative electrode ear 23c is corroded. Therefore, the Sb-containing concentration of the negative electrode lattice body 23a and the negative electrode ear 23c should be substantially free of Sb by making it less than 0.001% by mass.

  The negative electrode shelf for collective welding of the negative electrode ears 23c is made of a Pb—Sn—Se alloy that does not contain Sb. When Sb is included, Ca and Sb in the negative electrode ear 23c react to cause corrosion of the negative electrode ear 23c, so that the negative electrode shelf alloy has an Sb content of 0.001 as in the case of the negative electrode lattice body 23a and the negative electrode ear 23c. By making it less than mass%, it is set as the state which does not contain Sb substantially.

  By adding Se to the Pb—Sn alloy as the negative electrode shelf alloy, the corrosion that is remarkably generated in the Pb—Sn alloy crystal is suppressed, and in particular, the negative electrode shelf 26 and the pole columns and inter-cell connected bodies joined thereto. Corrosion at the joint with the connecting member 27 made of a Pb—Sb alloy in consideration of weldability and strength can be suppressed.

  From the viewpoint of strength and corrosion resistance, the Sn content concentration contained in the negative electrode shelf alloy is preferably in the range of 1.0 mass% to 3.0 mass%. If the Sn content concentration is less than 1.0 mass%, the strength as the negative electrode shelf is insufficient. Moreover, since addition of Sn exceeding 3.0 mass% increases the amount of negative electrode shelf corrosion slightly, it is preferable to set it as said range.

  Moreover, the effect of inhibiting corrosion is recognized when the Se content concentration contained in the negative electrode shelf alloy is 0.0005% by mass. On the other hand, the addition of 0.05% by mass or more of Se does not increase the corrosion-inhibiting effect, and the material cost increases as the addition amount of Se increases, so the range is from 0.0005% to 0.05% by mass. And it is sufficient.

  Note that the corrosion of the joint portion between the connection member 27 and the negative electrode shelf 26, which is the subject of the present invention, occurs in a state in which the joint portion is immersed in dilute sulfuric acid electrolyte solution. It should be applied to a liquid lead-acid battery that has been immersed in a liquid.

  Hereinafter, the effects of the present invention will be described with reference to examples.

  In the negative electrode weld 31 shown in FIG. 3, as shown in Table 1, the composition of the negative electrode ear 32 is Pb-0.07 mass% Ca, and the alloy composition of the negative electrode connection member 33 is Pb-2.5 mass%. Then, the alloy composition of the negative electrode shelf 34 was variously changed, and a 12V48Ah lead storage battery for starting an automobile was produced. Incidentally, in the example of FIG. 3, an example in which an inter-cell connection body is used as the negative electrode connection member is shown, but in the electrode plate group located on the negative electrode terminal side, the negative electrode pole column is connected as the connection member. When the Sb qualitative analysis in the negative electrode ear 32 was performed, the Sb-containing concentration was less than the detection limit (0.0001% by mass) and was substantially free of Sb. In addition, when the Sb qualitative analysis in the Pb-Sn alloy used as the negative electrode shelf 34 was conducted, the Sb-containing concentration was less than the detection limit (0.0001% by mass), and was substantially free of Sb.

In the above lead storage battery, a positive electrode plate in which an expanded lattice body of Pb-0.06 mass% Ca-1.60 mass% Sn was filled with a positive electrode active material of PbO ₂ was used. Further, as described above, a negative electrode plate in which a Pb-0.07 mass% Ca expanded lattice was filled with a spongy Pb negative electrode active material was used.

  And the negative electrode plate was accommodated in the microporous bag-like polyethylene separator, and the electrode group comprised by five positive electrode plates and six negative electrode plates was created. Six of these electrode plate groups are housed in a battery case having six cell chambers, each electrode plate group is connected in series by resistance welding, a lid is joined to the opening of the battery case, and insert molding is performed on the lid. The positive electrode pole column was welded to one of the paired lead bushing terminals, and the negative electrode pole column was welded to the other one lead bushing terminal to produce an unformed lead storage battery.

  The negative electrode welded portion 31 is formed by inserting a plurality of negative electrode ears 32 into the comb portion of the comb blade-shaped mold, and adding the lead shelf alloy of the negative electrode shelf alloy to the upper portion of the negative electrode ear 32 exposed from the comb and the negative electrode ears 32. The connecting member 33 was placed on the side and added lead was melted and solidified with a burner flame.

Then, a dilute sulfuric acid electrolyte solution was poured into each of the six cell chambers, and electricity was applied between the lead bushing terminals to obtain a charged lead-acid battery. In this state, the joint between the negative electrode shelf 34 and the connection member 33 was immersed in a dilute sulfuric acid electrolyte solution having a density of 1.290 g / cm ³ (when converted to 20 ° C.).

  In these lead-acid batteries of Table 1, the electrolyte surface is 1) a state in which the negative electrode shelf-connecting member joint is exposed from the electrolytic solution, and 2) a state in which the negative electrode shelf-connecting member joint is immersed in the electrolytic solution. And a constant voltage trickle charge of 15.0 V was performed continuously for 4 weeks. In the case where the electrolyte surface was 1), the test temperature was 85 ° C., and in the case where the electrolyte surface was 2), the test temperature was 95 ° C. When the negative electrode shelf-connecting member junction is exposed from the electrolyte, the junction between the negative electrode ear and the negative electrode shelf is also exposed from the electrolyte, and the negative electrode shelf-connecting member junction is immersed in the electrolyte. In this case, the joint between the negative electrode ear and the negative electrode shelf was also immersed in the electrolyte.

  After the trickle charge was completed, the battery was disassembled, the negative electrode shelf welded portion was taken out, and the presence or absence of corrosion between the negative electrode shelf and the connecting member and the state thereof, and the occurrence rate (%) of corrosion disconnection between the negative electrode ear and the negative electrode shelf were investigated. In addition, about the presence or absence of corrosion between a negative electrode shelf and a junction part, in the battery after a test, the cross-sectional area (S) of the junction part between a negative electrode shelf and a connection member was calculated | required, and this cross-sectional area (S) of a test is before The percentage ((S / S0) × 100) with respect to the joint area (S0) between the negative electrode shelf and the connection member in the battery was calculated as a connection part remaining rate (%), and was evaluated quantitatively. When this ratio is 100%, there is no corrosion, and when it is 50%, it indicates that the area of the joint has been reduced to 50% due to corrosion. These results are shown in Table 2.

  From the results shown in Table 2, in the battery in which the negative electrode shelf was made of Pb—Sb alloy, the corrosion breakage of the negative electrode ear occurred with the negative electrode shelf-connecting member junction exposed from the electrolytic solution surface. . On the other hand, no corrosion breakage of the negative electrode ear occurred in the state where the above-mentioned joint was immersed in the electrolyte surface. Corrosion disconnection of the negative electrode ear is presumed to be caused by an intermetallic compound produced by combining Sb contained in the negative electrode shelf and Ca contained in the negative electrode ear.

  In these batteries, corrosion between the negative electrode shelf and the connecting member was hardly recognized regardless of the position of the electrolyte surface.

  On the other hand, in the battery in which the negative electrode shelf is made of a Pb—Sn alloy containing no Sb, no corrosion breakage of the negative electrode ear occurred regardless of the position of the electrolyte surface. This is probably because Ca in the negative electrode ear does not come into contact with Sb by not including Sb in the negative electrode shelf, so that corrosion of the negative electrode ear and disconnection due to this were suppressed. Moreover, the corrosion between the negative electrode shelf and the connection member hardly progressed at the position of the electrolytic solution surface.

  However, in the battery of the comparative example in which the electrolytic solution surface immerses the joint between the negative electrode shelf and the connection member and Se is not added to the Pb—Sn alloy of the negative electrode shelf, the corrosion proceeds at the joint. The area of the joint portion was reduced to 40% or 45% of the initial state. This corrosion progressed remarkably on the negative electrode shelf side of the joint. In this state, sufficient strength is not ensured, and the electrical resistance during energization increases, so that the discharge voltage during high-rate discharge may decrease.

  On the other hand, in the lead storage battery of the present invention using the Pb—Sn—Se alloy as the negative electrode shelf, the remaining rate is 86 to 96%, and corrosion at the joint between the negative electrode shelf and the connecting member is remarkably suppressed. In both cases of Sn concentration of 1.0% by mass and 3.0% by mass, the addition of 0.0005% by mass of Se content shows a corrosion inhibiting effect.

  Further, in the case of 0.07% by mass exceeding Se content concentration of 0.05% by mass, a remarkable corrosion-inhibiting effect is recognized, but compared with the case of Se content concentration of 0.05% by mass, negative electrode shelf-connection Since the cross-sectional area of the joint portion of the member is slightly reduced, it is preferably 0.05% by mass or less.

  In the lead storage battery of the present invention, as described above, by adding Se to the Pb—Sn alloy of the negative electrode shelf, it is possible to suppress corrosion that occurs at the joint with the Pb—Sb alloy as the connecting member. . In the first place, the corrosion that occurs in this part is due to the discontinuous composition on the connecting member side and the negative electrode shelf side, so that when forming a joint, that is, on the negative electrode shelf side adjacent to this joint during solidification after welding. This is thought to be due to the occurrence of fine gaps. In the present invention, it is considered that the addition of Se to the Pb—Sn alloy prevents the formation of this gap and suppresses the progress of corrosion.

  In addition, in a battery in which the joint between the negative electrode shelf and the connection member is immersed in dilute sulfuric acid electrolyte, the joint may be exposed from the dilute sulfuric acid electrolyte due to a decrease in water in the electrolyte. Even in such a case, the lead storage battery of the present invention can suppress corrosion disconnection of the negative electrode ear.

  As described above, according to the present invention, the corrosion between the negative electrode shelf and the connecting member that occurs at the time of high temperature use is remarkably suppressed, so that lead used in automobiles, such as lead acid batteries for starting, is used at high temperatures. Suitable for storage batteries.

The figure which shows the electrode group of lead acid battery The figure which shows the lead acid battery of this invention The figure which shows the negative electrode welding part of the lead acid battery of an Example

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Positive electrode plate 11a Positive electrode ear 12 Negative electrode plate 12a Negative electrode ear 12b Negative electrode active body 13c Negative electrode active material 13 Separator 14 Positive electrode shelf 15 Negative electrode shelf 16 Terminal 17 Connection member 21 Lead storage battery 22 Positive electrode plate 23 Negative electrode plate 23a Negative electrode lattice body 23b Negative electrode active material 23c Negative electrode ear 24 Separator 25 Electrode plate group 26 Negative electrode shelf 27 Connection member 31 Negative electrode welded portion 32 Negative electrode ear 33 (of negative electrode) connection member 34 Negative electrode shelf

Claims (2)

A positive electrode plate and a negative electrode plate are combined via a separator, and a negative electrode shelf for collectively welding negative electrode ears led out from the negative electrode plate, and a connecting member joined to the negative electrode shelf, the negative electrode shelf and the connecting member A lead-acid battery having a joint immersed in an electrolyte, wherein the negative electrode ear is made of a Pb—Ca alloy containing no Sb, the connecting member is made of a Pb—Sb alloy, and the negative electrode shelf is made of Pb containing no Sb. -Lead-acid battery characterized by consisting of a Sn-Se alloy. The Pb-Sn-Se alloy constituting the negative electrode shelf includes 1.0 to 3.0 mass% of Sn and 0.0005 mass% to 0.05 mass% of Se. Lead acid battery of description.

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