JP2006066254A - Lead-acid storage battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a long lifetime lead-acid storage battery in which the variations of lifetime characteristics are suppressed, by reducing the deceleration speed of the storage battery and by suppressing uneven formation of an Sn-Sb containing layer on a grid base material surface due to cracks or breakages of a Pb-Sn-Sb alloy sheet, caused when integrally rolling the Pb-Sn-Sb alloy sheet with a positive electrode grid base material sheet. <P>SOLUTION: This is the lead-acid storage battery provided with a positive electrode plate, in which a positive electrode active material is filled in a positive electrode grid body which does not contain Sb, and a negative electrode plate, in which a negative electrode active material is filled in a negative electrode grid body which does not contain Sb. A first surface layer which contains Sb and does not contain Sn is provided at least on one part of a face, in which the positive electrode grid body contacts with the positive electrode active material, and a second surface layer which contains Sn and does not contain Sb is provided, at least on one part of a face in which the positive electrode grid body contacts with the positive electrode active material and which does not have the first surface layer. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a lead-acid battery.

  Lead-acid batteries are used for various purposes such as vehicle engine starting and backup power supply. Among them, the lead acid battery for starting supplies power to various electric / electronic devices mounted on the vehicle as well as supplying power to the cell motor for starting the engine. After the engine is started, the battery is charged by the alternator. Here, the output voltage and output current of the alternator are set so that charging and discharging of the battery are balanced and the SOC (charged state) of the battery is maintained at 90 to 100%.

  On the other hand, various electric devices are mounted on the vehicle, and the load current of the electric devices may exceed the power generation capacity of the alternator during idling as well as when the engine is stopped. In such a case, the insufficient power is covered by the storage battery. As a result, the discharge depth of the storage battery tends to be deeper.

  Further, except for some vehicles, the storage battery is generally mounted in the engine room. In recent years, the degree of integration of equipment in an engine room has increased due to higher performance or smaller size and weight of vehicles. As a result, the operating temperature of the storage battery tends to increase, and it is not rare that it is used in a temperature atmosphere exceeding 80 ° C.

  In order to improve the battery life when used at a deeper discharge depth in such a high-temperature atmosphere, for example, Patent Document 1 discloses lead containing tin and antimony on the surface of a positive electrode lattice of a lead-calcium-tin alloy. It has been shown to form an alloy layer. Tin and antimony present on the surface of the positive electrode lattice suppress the deterioration of the active material and the formation of a high resistance layer at the active material-lattice interface, and improve the lifetime characteristics in deep discharge.

In particular, a part of antimony disposed on the surface of the positive electrode lattice is trapped by the positive electrode active material, but a small amount of the other part elutes in the electrolytic solution and is deposited on the negative electrode plate. Antimony deposited on the negative electrode active material has a function of lowering the charging voltage by preciously shifting the charging potential of the negative electrode. As described above, the reduction of the charging voltage in the constant voltage charging control increases the charging current. As a result, the amount of charged electricity in the positive electrode is secured, and the deterioration of the positive electrode due to insufficient charging and the short life of the storage battery due to this are suppressed. Such a configuration is extremely effective in improving the life characteristics of the lead-acid battery in a high temperature atmosphere, and has been partly put into practical use.
JP-A-3-37962

  However, the lead-acid battery having the above-described configuration impairs maintenance-free properties because Sb contained in a small amount on the surface of the positive electrode lattice moves to the negative electrode. In other words, the decrease in self-discharge performance among maintenance-free properties is not a problem for practical use in view of the vehicle frequency that is normally assumed, but with regard to liquid reduction performance, which is another indicator of maintenance-free properties. There was a problem that the liquid reduction rate increased as it approached the end of life of the storage battery. And such a tendency is accelerated more as the use temperature of a storage battery becomes high temperature.

In addition, as a method for manufacturing a positive electrode lattice body in which a layer containing Sn—Sb is formed on the surface, Pb—
A method of forming a positive electrode grid by forming an opening for filling an active material in a sheet obtained by spraying a Sn—Sb alloy or by rolling and integrating a Pb—Sn—Sb alloy sheet on a positive electrode grid base material sheet. In particular, the latter method is effective in that the thickness of the surface layer can be uniformly formed and can be manufactured with relatively simple equipment. However, when the latter method is used, Pb- When the amount of Sb in the 5 wt% Sn-5 wt% Sb alloy is reduced, the Pb-Sn-Sb alloy sheet is rolled and integrated with the Pb-Sn-Sb alloy sheet and the positive electrode lattice base material sheet. In other words, cracks and breaks occur, and the surface layer cannot be stably formed on the base material sheet, and the effect of improving the life characteristics due to the formation of the Pb—Sn—Sb layer is impaired.

  Furthermore, Sn in the Pb—Sn—Sb layer is present at the positive electrode lattice-active material interface, thereby suppressing the generation of passive states at this interface and the resulting capacity reduction. Sb is more than the Pb—Sn—Sb layer. Elution improves the bonding between the positive electrode active material particles, and has the effect of improving the charge acceptability of the negative electrode by moving to the negative electrode. However, by adding both Sn and Sb to Pb, In the case of the -Sn-Sb layer, when Sb elutes, Sn dissipates from the positive electrode lattice-active material interface, so that the effect of Sn described above is impaired, and the intended effect cannot be obtained. It was.

  The present invention reduces a deceleration speed of a storage battery and lattice base material due to cracking or fracture of a Pb-Sn-Sb alloy sheet generated when a Pb-Sn-Sb alloy sheet and a positive electrode lattice base material sheet are rolled and integrated. The present invention provides a long-life lead-acid battery in which variation in life characteristics is suppressed by suppressing uneven formation of the Sn-Sb layer containing Sn on the surface.

  In order to solve the above-described problems, the present invention provides a positive electrode plate in which a positive electrode lattice body containing no Sb is filled with a positive electrode active material, and a negative electrode plate in which a negative electrode lattice body containing no Sb is filled with a negative electrode active material. A lead storage battery comprising: a first surface layer containing Sb and not containing Sn on at least a part of a surface of the positive electrode lattice body in contact with the positive electrode active material, wherein the positive electrode lattice body is the positive electrode active material And a second surface layer that contains Sn and does not contain Sb on at least a part of the surface that does not have the first surface layer, and is a conventional Pb-Sn. -By replacing the Sn layer with the Pb-Sb layer as the first surface layer and the Pb-Sn layer as the second surface layer individually, the Sb addition effect and the Sn addition effect are both compatible and stable. A long-life lead-acid battery can be obtained. Furthermore, in the Pb—Sb—Sn layer, if the Sb concentration is decreased to 3 wt% or less for the purpose of reducing the amount of liquid reduction, the adhesion between the Pb—Sn—Sb layer and the positive electrode lattice base material sheet is impaired, and the lifetime Although the performance is lowered, by providing the surface layer individually as in the present invention, such a decrease in adhesion can be suppressed, and a decrease in life due to this decrease in adhesion can be suppressed.

  According to the present invention, it is possible to improve the life characteristics particularly in a high temperature atmosphere.

  Embodiments of the present invention will be described below.

The base material of the positive electrode lattice used for the lead storage battery of the present invention is made of a lead alloy substantially free of Sb. As a lead alloy not containing Sb, a Pb—Ca—Sn alloy is used in terms of strength and corrosion resistance. The amount of Ca in the positive electrode lattice is 0.03 to 0.10% by mass from the viewpoint of lattice strength, and the amount of Sn is 1.00 to 2.00% by mass from the viewpoint of lattice strength and corrosion resistance. Is appropriate. In the present invention, the fact that the positive electrode lattice does not substantially contain Sb means 0.002 mass% or less. Even if this amount of Sb is included in the positive electrode lattice,
It does not shift to the negative electrode, and as a result, it does not affect the maintenance-free performance of the battery, such as the amount of self-discharge in the negative electrode and the reduction of the electrolyte.

  The lead acid battery of the present invention is a lead acid battery comprising a positive electrode plate in which a positive electrode grid body containing no Sb is filled with a positive electrode active material, and a negative electrode plate in which a negative electrode grid body containing no Sb is filled with a negative electrode active material. The positive electrode grid is provided with a first surface layer containing Sb and not containing Sn on at least a part of a surface in contact with the positive electrode active material, the positive electrode grid is in contact with the positive electrode active material, and A second surface layer containing Sn and not containing Sb is provided on at least a part of the surface not having the first surface layer. As a method for forming these surface layers, as shown in FIG. A first foil 2 having the same composition as the first surface layer is formed on one surface of the sheet 1 composed of the lattice alloy base material, and a second surface layer is formed on the other surface of the sheet 1 by the second composition having the same composition. Foil 3 can be stacked and rolled and integrated by rolling roller 4 That.

  Then, as shown in FIG. 2, an opening 21 for filling the positive electrode active material is formed in the rolled sheet 11, and the positive electrode active material paste 22 is filled in the opening 21. And while cutting to a single electrode plate, the current collection ear | edge part 23 is formed, and the positive electrode plate 24 used for the lead acid battery of this invention is obtained through aging drying. The positive electrode plate 24 has a configuration in which a positive electrode active material paste 22 is filled in a positive electrode lattice body 25 formed by forming an opening 21 and current collecting ears in a sheet 11 and cutting it into a single electrode plate shape. is doing. The positive electrode active material paste 22 finally becomes a positive electrode active material 26 mainly composed of lead dioxide through an aging drying process and a chemical charging process. FIG. 3 is a cross-sectional view of the positive electrode plate 24 of this embodiment.

  A first surface layer 27 containing Sb is formed on one surface of the positive electrode grid 25 in contact with the positive electrode active material, and the second surface containing Sn is not formed on the other surface. A surface layer 28 is formed.

  Here, the first surface layer is preferably a lead alloy containing 3 wt% or less of Sb for the purpose of suppressing an increase in liquid reduction due to Sb transferred to the negative electrode, and the second surface layer is Sn. It is preferable that the lead alloy contain 3 wt% or more of Sn for the purpose of suppressing the generation of a passive layer at the positive electrode lattice-active material interface due to and suppressing the capacity reduction due thereto.

  Next, similarly to the positive electrode lattice body, the negative electrode lattice body is also made of a lead alloy substantially not containing Sb. As with the positive electrode lattice, a Pb—Ca—Sn alloy can be used. However, since the negative electrode lattice is not affected by corrosion as compared with the positive electrode, the addition of Sn is not always necessary. However, Sn, as described above, may improve the lattice strength or improve the molten lead flowability of the molten lead at the time of forming the cast lattice, so it may be added in an amount of about 0.2% to 0.6% by mass. In addition, the amount of Ca in the negative electrode lattice is added in an amount of 0.03 to 0.10% by mass for the purpose of ensuring the lattice strength as in the case of the positive electrode. Note that the presence of Sb in the negative electrode lattice directly affects the self-discharge of the negative electrode and the reduction of the electrolyte solution, so the content is made 0.001% by mass or less. Moreover, the manufacturing method of a negative electrode grid body can be obtained by the method similar to a positive electrode grid body.

  A negative electrode active material paste is filled into the negative electrode lattice body obtained as described above, and is aged and dried to produce an unformed negative electrode plate. The negative electrode plate and the positive electrode plate described above are preferably combined with a mat separator made of acid-resistant fibers such as glass fibers and polypropylene resin fibers to constitute an electrode plate group. The lead storage battery of this invention can be obtained by comprising a lead storage battery using this electrode group.

  Needless to say, it is possible to use a separator made of a conventional polyethylene sheet. However, in order to suppress the softening and falling off of the positive electrode active material generated by repeating the charge / discharge cycle, the above-mentioned mat is used. It is preferable to use a separator.

  As an example of a specific lead-acid battery, six of the above-mentioned electrode plate groups are housed in a battery case, the electrode plate groups are connected in series, the battery cell opening is covered with a lid, and both ends in series connection The pole column led out from the electrode plate group located at is inserted into a terminal bushing insert-molded in the lid, and the terminal bushing and the pole column tip are welded. Then, dilute sulfuric acid electrolyte is injected from the injection port provided on the lid, and chemical charging is performed to obtain a lead storage battery. In addition, after chemical conversion charging, it has the structure which the electrode plate surface which contributes to at least charge / discharge reaction of the positive electrode plate and negative electrode plate which comprise an electrode plate group was immersed in electrolyte solution.

  A positive electrode plate made of a Pb—Ca—Sn alloy, a negative electrode plate made of a Pb—Ca—Sn alloy, and a separator made of a glass mat were used, and the first surface layer and the second surface layer were shown in Table 1. Each battery was produced.

次いで、それぞれの電池に対して寿命試験と減液性能試験を行った。その結果を表２に示す。

Next, a life test and a liquid reduction performance test were performed on each battery. The results are shown in Table 2.

ここで、寿命試験は、７０℃気相中で、２５Ａ、４分間放電を行った後１４．８Ｖ（最大電流２５Ａ）、１０分間充電を行ったものを一サイクルとし、前記サイクルの４８０サイクル毎に２５℃気相中で、３５６Ａ、３０秒放電時の放電末期電圧を測定し、前記放電末期電圧が７．２Ｖに低下するまでのサイクル数を寿命サイクル数とした。

Here, in the life test, 14.8 V (maximum current 25 A) after discharging for 4 minutes at 25 ° C. in a gas phase at 70 ° C. for 10 minutes is defined as one cycle, and every 480 cycles of the above cycle. In the gas phase at 25 ° C., the end-of-discharge voltage was measured at 356 A for 30 seconds, and the number of cycles until the end-of-discharge voltage dropped to 7.2 V was defined as the number of life cycles.

  Further, in the liquid reduction performance test (measurement of the liquid reduction amount), after charging in a 40 ° C. water tank for 14.4 V (constant voltage) for 500 hours, the decrease in mass before and after charging was defined as the liquid reduction amount. The initial liquid reduction amount in Table 2 is the liquid reduction amount measured with a new battery, and the post-test liquid reduction amount is the liquid reduction amount measured with the battery after performing a life test.

  As can be seen from Table 2, in a battery (for example, battery A or battery D4) that does not include both the first surface layer and the second surface layer, the life cycle is not sufficient. In addition, although the life cycle of the battery B1 is good, the amount of liquid reduction after the test (that is, at the end of the life) has greatly increased, so the liquid level is regularly controlled every predetermined period. However, the liquid level falls below the minimum liquid level during this period, and the negative electrode strap and the electrode plate are exposed from the electrolytic solution, so that the decrease in capacity proceeds abruptly and corrosion occurs in the negative electrode strap.

  On the other hand, in the battery of the present invention including both the first surface layer and the second surface layer (for example, the battery C1 and the battery D2), the life cycle and the amount of liquid reduction are good, and further More preferably, the amount of Sb contained in the first surface layer is 3.0 wt% or less and the amount of Sn contained in the second surface layer is 3.0 wt% or more.

Accordingly, the present invention is a lead-acid battery comprising a positive electrode plate in which a positive electrode grid body containing no Sb is filled with a positive electrode active material, and a negative electrode plate in which a negative electrode grid body containing no Sb is filled with a negative electrode active material. A first surface layer containing Sb and not containing Sn on at least a part of a surface of the positive electrode grid that is in contact with the positive electrode active material; wherein the positive electrode grid is in contact with the positive electrode active material; and By providing the second surface layer containing Sn and not containing Sb on at least a part of the surface that does not have one surface layer, there is an effect that life characteristics in a high temperature atmosphere can be improved. Can do.

  Since the lead storage battery according to the present invention can improve the life characteristics under a high temperature atmosphere, it is useful as a lead storage battery for vehicles.

The figure which shows the method of forming the 1st surface layer and the 2nd surface layer on a sheet | seat The figure which shows the method of forming a positive electrode plate from a sheet | seat Sectional drawing of the positive electrode plate of the lead acid battery of a present Example

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Sheet 2 1st foil 3 2nd foil 4 Rolling roller 11 Sheet 21 Opening part 22 Positive electrode active material paste 23 Current collection ear | edge part 24 Positive electrode plate 25 Positive electrode grid body 26 Positive electrode active material 27 First surface layer 28 Second Surface layer

Claims (3)

A positive electrode plate in which a positive electrode active material is filled in a positive electrode lattice body containing no Sb;
A lead-acid battery comprising a negative electrode plate filled with a negative electrode active material in a negative electrode grid that does not contain Sb,
A first surface layer that includes Sb and does not include Sn on at least a part of a surface of the positive electrode grid that is in contact with the positive electrode active material;
A lead acid battery in which the positive electrode lattice body is in contact with the positive electrode active material, and a second surface layer containing Sn and not containing Sb is provided on at least a part of the surface not having the first surface layer. The lead acid battery according to claim 1, wherein the amount of Sb contained in the first surface layer is 3.0 wt% or less. The lead acid battery according to claim 1, wherein the amount of Sn contained in the second surface layer is 3.0 wt% or more.

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