JP2008159510A - Lead alloy grid and lead storage battery using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lead storage battery that uses a lead alloy grid, made of lead or a lead alloy which can maintain a maintenance-free property, and to improve the cycle characteristics. <P>SOLUTION: In the lead alloy grid with a surface layer provided on a base layer made of lead or a lead alloy, the surface layer is a lead alloy layer containing at least germanium by 0.0001 to 1.0 mass%. The surface layer is preferably be a lead alloy layer furthermore, containing antimony and tin. The lead storage battery is provided with the lead alloy grid as a cathode grid. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a lead alloy grid in which a surface layer is provided on a base material layer made of lead or a lead alloy, and a lead storage battery using the lead alloy grid.

  Lattice alloys used in lead-acid batteries can be broadly classified into lead-antimony alloys and lead alloys that do not substantially contain antimony. Lead alloys that do not contain antimony include lead-calcium alloys. In recent years, maintenance-free characteristics have been regarded as important, and lead-calcium alloys containing no antimony have been frequently used because they have characteristics suitable for maintenance-free. In addition, non-leakable liquid-type sealed lead-acid batteries with a liquid impregnated and retained in separators are increasing, mainly for large-sized installations and small consumers. Calcium-based alloys are used.

  However, when a lead-calcium alloy containing no antimony is used for the positive electrode grid, the depth of discharge is deep, and the repetition of frequent charge / discharge cycles may shorten the life. This is because a lead sulfate layer, which is a discharge product and also an insulator, is preferentially formed between the positive electrode grid and the positive electrode active material, so that there remains an unreacted active material. It is considered that the discharge reaction stops.

  On the other hand, when a lead-antimony alloy is used for the positive electrode, it becomes difficult to form the lead sulfate layer as described above, and as a result, a stable life can be obtained. However, when this alloy lattice is applied to a maintenance-free or leak-free type storage battery, antimony elutes along with the corrosion of the positive electrode lattice during use, and then deposits on the negative electrode, and a part is released as stibine. However, the remainder remains on the negative electrode plate, resulting in a decrease in hydrogen overvoltage, leading to an increase in the amount of liquid reduction and self-discharge, resulting in a loss of maintenance-free or no-leakage type functions.

Therefore, in order to obtain a lead-acid battery with stable charge / discharge cycle performance while having a maintenance-free function, a lead alloy layer containing antimony is formed on the surface of the base layer made of a lead-calcium alloy containing no antimony. Although it has been proposed (see Patent Documents 1 and 2), the cycle life has not been sufficiently improved.
JP-A 63-148556 JP 2003-163007 A

It is also known to add germanium or a germanium compound to the positive electrode active material in order to improve the life performance of a lead storage battery using a lead-calcium alloy for the positive electrode grid (see Patent Documents 3 and 4).
Patent Document 3 states that “in terms of lifetime performance, when germanium oxide is added in an amount of 0.01% or more and 2% or less, it is considerably improved as compared with a conventional battery not added with germanium oxide. I don't know, but it seems that germanium plays a role in suppressing softening (breaking of the bond of the active material), which is one of the deterioration of the positive electrode active material.In this example, germanium oxide was used as the germanium compound. However, there was no significant difference in the effect even when metal germanium was used. ”(Paragraphs [0010] to [0011]), Patent Document 4 states that“ the reason why the life performance is greatly improved is not clear. However, the inclusion of tin in both the lattice and the active material suppresses the formation of the passive layer, suppresses the formation of the passive layer by germanium, and causes the germanium in the active material to It is thought that each action effect, such as softening due to increased binding force between substances and suppression of dropout, brought about a combined synergistic effect by the configuration of the present invention, leading to an increase in specific surface area and an improvement in utilization rate. (Paragraph [0021]), but only concerns the action of germanium in the active material, and suggests adding germanium to the positive electrode lattice to improve lifetime performance. It is not a thing.
JP-A-10-106575 JP-A-10-144318

Furthermore, Patent Document 5 states that “a lead alloy containing no antimony and containing 0.05 to 3.0 wt% tin and 0.001 to 0.2 wt% germanium. Is used for the positive electrode grid. "(Claims) is described. However, Patent Document 5 states that “a lead content is prevented by adjusting the lead alloy composition, and that the tin content in the lead alloy containing no antimony is 0.05 to 3.0.
A lead alloy having a weight% and germanium content of 0.001 to 0.2% by weight is used for the positive electrode grid. According to Tables 1 and 2, in the lead-acid battery using the lead alloy lattice containing only germanium without containing tin, the cycle is described. Since it is shown that the life is not improved (battery No. 6), the invention described in Patent Document 5 is other than “adjusting the lead alloy composition” in order to improve the life performance of the lead storage battery. It does not suggest the adoption of the method, nor does it suggest the effect of improving the life performance by including germanium in the positive electrode lattice.
Japanese Patent Publication No. 6-27295

Further, Patent Document 6 describes a positive electrode lattice in which a surface layer of a lead alloy having a composition different from the composition of the base material is provided on a base material made of lead or a lead alloy substantially free of antimony, and the surface layer One kind selected from the group consisting of copper, silver, gold, zinc, cadmium, germanium, indium, thallium, gallium, tin, arsenic, antimony, bismuth, selenium, tellurium, chromium, molybdenum, nickel and cobalt Although it is also shown that the above metal is contained in an amount of 3 to 95% by mass, in order to improve the voltage, it is only described that the above-mentioned metal is contained in the lead alloy of the surface layer, and the cycle life is reduced. There is no description about improving, and there is no description about containing the above metals in an amount of less than 3% by mass. Therefore, in the invention described in Patent Document 6, in order to improve cycle life, a surface layer of a lead alloy containing a small amount of germanium is provided on a base material made of lead or a lead alloy substantially free of antimony. It does not suggest.
US Pat. No. 4,107,407

  This invention makes it a subject to improve cycle life, maintaining a maintenance-free characteristic about the lead storage battery using the lead alloy grid | lattice which makes lead or lead alloy a base material.

The present invention employs the following means in order to solve the above problems.
(1) In a lead alloy lattice in which a surface layer is provided on a base layer made of lead or a lead alloy, the surface layer is a lead alloy layer containing at least 0.0001 to 1.0% by mass of germanium. Lead alloy grid.
(2) The lead alloy lattice according to (1), wherein the surface layer is a lead alloy layer further containing antimony. It is preferable that the surface layer is a lead-antimony-germanium alloy layer containing 1.0 to 10% by mass of antimony.
(3) The lead alloy lattice according to (2), wherein the surface layer is a lead alloy layer further containing tin. It is preferable that the surface layer is a lead-antimony-tin-germanium alloy layer containing 1.0 to 10% by mass of tin.
(4) The lead alloy lattice according to any one of (1) to (3), wherein the base material layer is made of a lead-calcium alloy substantially free of antimony.
(5) A lead storage battery using the lead alloy grid according to any one of (1) to (4) as a positive grid.

  By using the lead alloy lattice of the present invention as a positive electrode lattice or a negative electrode lattice, even when the depth of discharge is deep and frequent, the maintenance-free characteristics are maintained, and a lead storage battery having an excellent cycle life can be obtained. .

Hereinafter, embodiments of the present invention will be described.
In the lead alloy lattice in which lead or a lead alloy substantially free of antimony is used as a base layer and a surface layer is provided on the base layer, the inventors of the present invention use a lead alloy layer containing germanium. It has been found that the cycle life of a lead storage battery using this lead alloy lattice is remarkably improved even if it does not contain other components. In the lead storage battery using the “lead alloy not containing antimony” for the positive electrode lattice, as shown in Patent Document 5, when the lead alloy contains only germanium, the cycle life is not improved. The alloy lattice is different from the conventional positive electrode lattice (lead alloy lattice) in improving the cycle life, and has an unpredictable operation effect.
The reason for the improvement in the life performance is that the surface layer of a lead alloy containing germanium is provided on the base material layer, thereby improving the durability of the lattice against elongation and suppressing the decrease in the current collecting function due to the elongation of the lattice. I think it was possible.

  The content of germanium in the surface layer in the lead alloy lattice of the present invention is preferably 0.0001 to 1.0% by mass. If the germanium content is less than 0.0001% by mass, the effect of improving the life performance is not sufficient, and if it is more than 1.0% by mass, the effect is saturated, so the above range is preferable.

  The life performance can be further improved by including antimony in the surface layer together with germanium. The content of antimony in the surface layer is not particularly limited, but when this lead alloy lattice is used for the positive electrode lattice, in order to suppress the formation of the lead sulfate layer and obtain a stable lifetime, 1.0 to 10 It is preferable to set it as the mass%. When the content of antimony is less than 1.0% by mass, formation of the lead sulfate layer may not be suppressed. When the content is more than 10% by mass, antimony eluted with corrosion of the positive electrode lattice is deposited on the negative electrode, The above range is preferred because of the possibility of adverse effects.

  By including tin together with germanium and antimony in the above surface layer, it is possible to improve charge acceptance characteristics even when deep discharge or discharge is left in cycle use, and to restore sufficient capacity by charging. it can. The content of tin in the surface layer is not particularly limited, but is preferably 1.0 to 10% by mass.

  The base material layer in the lead alloy lattice of the present invention may be lead or a lead alloy, and is not particularly limited, but is preferably lead or a lead alloy substantially free of antimony, and employs a lead-calcium alloy. be able to. The lead-calcium alloy may contain tin, aluminum, bismuth, silver or the like.

The lead alloy lattice of the present invention is produced by the following method.
First, a slab (lead strip) having an arbitrary thickness to be a base material layer is produced by casting lead or a lead alloy substantially free of antimony.
Next, a foil serving as a surface layer is produced by casting and rolling a flat plate made of a lead-germanium alloy, a lead-antimony-germanium alloy, or a lead-antimony-tin-germanium alloy.
Laminating a foil made of the above-described lead-germanium alloy, lead-antimony-germanium alloy, or lead-antimony-tin-germanium alloy as a surface layer on both sides or one side of the base material layer produced as described above, By rolling using a multi-stage rolling mill, they are integrated into a rolled sheet, and this rolled sheet is further processed into a grid by an expanding machine or a punching machine to produce a lead alloy grid.
In addition, when providing a surface layer (foil) by methods, such as crimping | bonding, thermal spraying, immersion to a molten lead alloy, and electroplating, it can also apply to a casting grating | lattice and can also be set as the lead alloy grating | lattice of this invention.
Further, the surface layer (foil) is not necessarily provided on both surfaces of the base material layer or the entire surface of one surface. That is, FIG. 1 (a) shows a schematic diagram of a lattice processed by an expanding machine, but a surface layer (foil) is not provided in the part that becomes the ear 1 and the frame 2 in FIG. 1 (a). It may be. 1 (a), FIG. 1 (b) (enlarged view of portion A in FIG. 1 (a)), FIG. 1 (c), FIG. 1 (d) (FIG. As shown in FIG. 1C, when the surface layer is provided on one side of the base material layer, the bone portion 31 connecting the nodule portions 32 is as shown in FIG. When the surface layer is provided on both surfaces of the base material layer, as shown in FIG. 1 (d), the surface layer appears only on one surface or two surfaces of the bone portion 31, so that it is processed into a lattice shape. Further, the surface layer may be formed on the entire surface of the bone portion 31 by thermal spraying of a lead alloy to be a surface layer (foil), electroplating, immersion in a lead alloy bath, or the like.

Using the lead alloy lattice produced as described above, a lead storage battery is produced in the usual manner.
Hereinafter, although an example explains the details, the present invention is not limited to an example.

(Preparation of positive electrode plate)
A lead-calcium-based lead alloy in which 0.06% by mass of calcium and 1.5% by mass of tin are added to raw lead produced by electrolytic refining is cast into a 9.5 mm thick slab, and a base material layer It was.
Seven types of lead-germanium alloys (Pb-Ge) with the amount of germanium added varied between 0.0001 and 1.5 mass%, the amount of germanium added is 0.5 mass%, and antimony added Five types of lead-antimony-germanium alloys (Pb-Sb-Ge) whose amount was varied between 0.5 and 15% by mass, and further the addition amount of germanium was 0.5% by mass and the amount of antimony added 17 kinds of five lead-antimony-tin-germanium alloys (Pb-Sb-Sn-Ge) in which the amount of tin is 5 mass% and the amount of tin is varied between 0.5 and 15 mass% A lead alloy was prepared. Each lead alloy was cast into a flat plate having a thickness of 2 mm and then rolled to prepare a foil (surface layer) having a thickness of 0.25 mm. The foil thus produced was laminated on both surfaces of the base material layer and integrated by rolling using a multi-stage rolling mill to obtain a rolled sheet having a thickness of 1.0 mm. The rolled sheet was developed with a rotary expander to produce the lead alloy lattice (positive electrode lattice) of the example.
Further, as a lead alloy lattice of a comparative example, a foil made of a lead-antimony alloy (Pb-Sb) containing 5% by mass of antimony, a lead-antimony-tin alloy containing 5% by mass of antimony and 5% by mass of tin ( A foil made of (Pb—Sb—Sn) was produced by the above-described method and laminated on the base material layer, and a lead alloy lattice (positive electrode lattice) was similarly produced. Furthermore, a positive electrode lattice without a foil was also produced.
The produced positive electrode grid was filled with a positive electrode plate paste. As the positive electrode plate paste, a paste obtained by mixing lead powder containing lead oxide as a main component and a predetermined amount of dilute sulfuric acid was used. The positive electrode grid filled with the positive electrode plate paste was aged at 50 ° C. for 3 days to obtain an unformed positive electrode plate.

(Preparation of negative electrode plate)
A lead-calcium-based lead alloy in which 0.05% by mass of calcium and 0.5% by mass of tin were added to raw lead produced by electrolytic refining was cast to prepare a negative electrode grid. The prepared negative electrode lattice was filled with a negative electrode plate paste. The paste for the negative electrode plate was prepared by adding lignin, carbon, and a predetermined amount of dilute sulfuric acid to lead powder mainly composed of lead oxide. An unformed negative electrode plate was obtained by aging the negative electrode lattice filled with the negative electrode plate paste at 50 ° C. for 3 days.

(Production of lead-acid battery)
An unformed electrode plate group was configured by laminating 5 unformed positive electrode plates and 6 unformed anode plates produced as described above via a polyethylene resin separator produced by an extrusion molding method. The unformed electrode plate group was inserted into the battery case, the lid was welded, and diluted sulfuric acid having a specific gravity of 1.23 (20 ° C.) was injected into the battery case. Thereafter, a battery formation is performed in a water bath at 35 ° C. (amount of electricity: 300% of the theoretical capacity of the positive electrode active material, formation time: 18 hours), and a 46B24 size lead storage battery (nominal voltage: specified in JIS D 5301). 12V, rated capacity: 36 Ah).

(Lead storage battery life test)
About the lead storage battery produced as mentioned above, the life test was done on condition of the following.
・ Discharge: 3.6A x 1h
・ Charging: 1.8A x 3h
・ Temperature: 40 ℃
In addition, the time when the voltage during discharge fell below 9.0 V was determined as the life.
The test results are shown in Table 1. The number of life cycles in the table is the storage battery No. The relative value when the life cycle number of 1 is 1.0 is shown.

From Table 1, a lead storage battery (No. 2) using a lead alloy lattice (positive electrode lattice) provided with a lead-germanium alloy (Pb—Ge) containing 0.0001 to 1.0 mass% of Ge as a surface layer (foil). -No.7) shows that the cycle life is remarkably improved as compared with the lead storage battery (No.1) using the positive electrode grid of the comparative example in which the surface layer (foil) is not provided. A lead storage battery (No. 8) using a lead alloy lattice provided with a Pb-Ge foil containing 1.5% by mass of Ge is provided with a Pb-Ge foil containing 1.0% by mass of Ge (No. 7), the cycle life is shortened, so the Ge content in the Pb-Ge foil is preferably up to 1.0% by mass.
When a lead storage battery (No. 10 to No. 14) using a lead alloy lattice (positive electrode lattice) made of lead-antimony-germanium alloy (Pb-Sb-Ge) is further added as a surface layer (foil). Further, the cycle life is further improved as compared with lead storage batteries (No. 2 to No. 8) in the case of lead-germanium alloy (Pb-Ge).
Furthermore, in the case of a lead storage battery (No. 16 to No. 20) using a lead alloy lattice (positive electrode lattice) made of lead-antimony-tin-germanium alloy (Pb—Sb—Sn—Ge) with tin added, Compared to lead-acid batteries (No. 10 to No. 14) in the case of lead-antimony-germanium alloy (Pb—Sb—Ge), the cycle life is slightly improved, but deep discharge or discharge was left untreated. In this case, there is an effect that the charge acceptance characteristic is improved. The reason for this is that, in addition to the effect of containing Ge by providing a layer containing Sn together with Ge on the lattice surface, as in the case where Sn is attached to the lattice surface of a conventional lead-acid battery, the lattice and The effect by changing the property of the high resistance layer formed at the interface with the active material is estimated.

  Further, a positive electrode lattice provided with a lead-antimony-germanium alloy (Pb-Sb-Ge) as a surface layer (foil) and a positive electrode lattice provided with a lead-antimony alloy (Pb-Sb) as a surface layer (foil). When compared, a positive electrode grid provided with a lead-antimony-tin-germanium alloy (Pb-Sb-Sn-Ge) as a surface layer (foil) and a lead-antimony-tin alloy (Pb-Sb) as a surface layer (foil) When comparing with the positive electrode lattice provided with -Sn), it can be said that the former has a significantly improved cycle life, so the effect of using antimony and germanium in combination with the surface layer is clear.

Schematic diagram of the expanded lattice Enlarged view of part A in FIG. A cross-sectional schematic view of a bone developed with an expanding machine with a surface layer on one side of a rolled sheet Schematic diagram of the cross-section of the bone developed with an expanding machine with surface layers on both sides of the rolled sheet

Explanation of symbols

1: Ear part 2: Frame bone part
3: Net-like part 31: Bone part 32: Nodule part

Claims (5)

  A lead alloy lattice in which a surface layer is provided on a base material layer made of lead or a lead alloy, wherein the surface layer is a lead alloy layer containing at least 0.0001 to 1.0% by mass of germanium. lattice.   The lead alloy lattice according to claim 1, wherein the surface layer is a lead alloy layer further containing antimony.   The lead alloy lattice according to claim 2, wherein the surface layer is a lead alloy layer further containing tin.   The lead alloy lattice according to any one of claims 1 to 3, wherein the base material layer is made of a lead-calcium alloy substantially free of antimony.   A lead storage battery using the lead alloy grid according to any one of claims 1 to 4 as a positive grid.

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