JP2008177157A - Lead storage battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To manufacture a battery with maintenance-free performance assured, and further, early capacity drop restrained. <P>SOLUTION: The lead storage battery is formed with at least one or more of alkali metals or alkaline earth metals added into chemical solution. An additive volume is from 300 to 4,000 ppm. A current collector contains at least one or more out of As, Sb, Bi (fifth group), Se, and Te (sixth group) elements, with a total of the additive volume from 30 to 150 ppm. A desired current-carrying electrical quantity of the formation is from 90 to 160% of a cathode active material theoretical volume of the lead storage battery. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a lead-acid battery for starting automobiles.

Conventionally, there has been a problem of causing an early capacity decrease during a charge / discharge cycle of a lead storage battery. This is due to the loss of conduction between the lattice and the active material due to the discharge of the lattice surface, resulting in a decrease in capacity. As one of the countermeasures, there is one that generates α-PbO ₂ that is difficult to discharge in the vicinity of the lattice so that the lattice surface does not discharge even when deep discharge is performed. As another representative example, a neutral sulfate solution is impregnated on an unformed positive electrode plate, then formed in an electrolyte mainly composed of dilute sulfuric acid, and a neutral electrolyte in an active material in the early stage of formation. And active material in the vicinity of the lattice are reacted to produce α-PbO ₂ , followed by diffusion of sulfuric acid in the electrolytic solution to produce β-PbO ₂ having excellent reactivity inside and on the surface There is. However, in this method, α-PbO ₂ is produced at non-uniform locations, the production amount is small, and the production amount is difficult to adjust.

  It also solves the problem of early capacity reduction of lead-acid batteries. As the positive grid alloy, antimony is 0.8 wt% to 3 wt%, arsenic is 0.1 wt% to 0.4 wt%, copper 0.0005 wt% or more and 0.03 wt% or less, silver 0.0005 wt% or more and 0.25 wt% or less, tin 0.0005 wt% or more and 0.1 wt% or less, and bismuth 0 There is one using a lead alloy containing 0.001% by weight or more and 0.03% by weight or less and nickel containing 0.0002% by weight or more and 0.003% by weight or less (Patent Document 1).

Japanese Patent Laid-Open No. 9-231981

  However, when a maintenance-free type battery is manufactured by a conventional method such as Patent Document 1, problems such as an increase in the amount of liquid reduction and a decrease in specific gravity occur, and the maintenance-free performance is significantly deteriorated. The problem to be solved by the present invention is to manufacture a battery that ensures maintenance-free performance and further suppresses an early capacity drop.

  The present invention is a lead storage battery using an unformed electrode plate made of a lead-calcium alloy current collector, and is formed by adding at least one alkali metal or alkaline earth metal to the chemical conversion solution. The chemical conversion liquid after completion of the chemical conversion contains 300 to 4000 ppm of alkali metal or alkaline earth metal. The lead-acid battery current collector contains at least arsenic (As), antimony (Sb), bismuth (Bi) (group 5 of the periodic table), selenium (Se), tellurium (Te) (group 6) elements. Contains one or more. The total of elements contained in the current collector is 30 to 150 ppm. The amount of energized electricity for the chemical conversion is 90 to 160% of the theoretical capacity of the positive electrode active material of the lead acid battery.

  According to the present invention, an early capacity drop can be suppressed even in a maintenance-free type battery.

  EXAMPLES Hereinafter, although this invention is demonstrated in detail based on an Example, this invention is not limited to the following Example at all, In the range which does not change the summary, it can change suitably and can implement.

  Hereinafter, embodiments of the present invention will be described in detail.

(Comparative example)
The lead acid battery of the comparative example was produced as follows.

  First, 15 kg of red lead and 110 L of dilute sulfuric acid (specific gravity 1.26: the same as below at 20 ° C.) were charged into a kneading mixer to prepare a red lead slurry. The red lead slurry and 850 kg of lead powder were put into a paste kneader and kneaded with 100 L of water to make a positive electrode active material paste. Next, 85 g of this positive electrode active material paste was filled in a lattice made of a calcium alloy, left to mature at a temperature of 50 ° C. and a humidity of 95% for 18 hours, and then left at a temperature of 110 ° C. for 2 hours. It dried and the unchemically formed positive electrode plate was made.

  Next, a negative electrode plate was made. First, a negative electrode active material paste was prepared by kneading lead powder, 15 wt% diluted sulfuric acid (specific gravity 1.26) with respect to the lead powder, and 12 wt% water with respect to the lead powder. Next, 80 g of the negative electrode active material paste was filled in a current collector made of a calcium alloy lattice, left to mature for 18 hours at 50 ° C. and 95% humidity, and then left at 110 ° C. for 2 hours. And dried to produce an unformed negative electrode plate.

  Next, eight unformed negative electrode plates and seven unformed positive electrode plates were alternately laminated via a separator to form each electrode plate group.

  Next, chemical conversion was performed. Charging was performed at 22.5 A in a 25 ° C. atmosphere at a constant current of 12 hours. The specific gravity of sulfuric acid used for charging was 1.240, and 700 ml of each cell was injected.

  By the above procedure, a comparative example 80D26 type lead-acid battery for automobile (described in JIS D5301) having a rated voltage of 12 V and a rated capacity (5 hour rate capacity) of 55 Ah was produced.

(Embodiment 1)
The lead storage battery of Embodiment 1 was produced as follows.

  An unformed negative electrode plate and an unformed positive plate are produced in the same manner as in the comparative example, and 8 unformed negative plates and 7 unformed positive plates are alternately laminated via a separator to form each plate group. It was. In addition, the thing containing 100 ppm of Bi and Sb was used for the positive electrode current collector.

  Next, chemical conversion was performed. Charging was performed at a constant current of 17 A for 12 hours in an atmosphere of 25 ° C. The specific gravity of sulfuric acid used for charging was 1.265, and 700 ml of each cell was injected. Sodium sulfate was added to the sulfuric acid so that the amount of Na after charging was 3000 ppm.

  By the above procedure, the 80D26 type automotive lead-acid battery (described in JIS D5301) of Embodiment 1 having a rated voltage of 12 V and a rated capacity (5-hour rate capacity) of 55 Ah was produced.

  FIG. 1 shows the cycle capacity change of the heavy load life test specified by JIS. The test conditions were 20A at an ambient temperature of 40 ° C. for 1 hour, and then charging / discharging was repeated with 5A charging for 5 hours as one cycle, and continued until the terminal voltage reached 10.2V at 20A every 25 cycles. Discharge was performed and the discharge duration was measured. The number of life cycles was the number of times that the capacity was half of the 5-hour rate capacity, that is, 22.5 Ah.

In the first embodiment, there is no capacity reduction at the beginning of the cycle as seen in the comparative example, and no large capacity reduction occurs until the end of the life. In addition, the number of cycles until the life judgment capacity is cut is increased. The capacity reduction at the initial stage of the cycle seen in the comparative example is a capacity reduction due to the fact that the active material is discharged at the lattice-active material interface due to deep charge / discharge and the current collecting property is reduced. In the first embodiment, the presence of α-PbO ₂ that is difficult to discharge at the lattice-active material interface suppresses the discharge at the lattice-active material interface and suppresses a rapid decrease in discharge capacity during the cycle. In addition to Bi and Sb, the same effect can be obtained when As, Se, or Te is used as the element to be contained in the positive electrode current collector.

  FIG. 2 shows the relationship between the amount of sodium (Na) contained in the chemical liquid after chemical conversion and the number of cycles of heavy load life. When the amount of sodium in the chemical conversion liquid is 300 ppm or more, it exceeds 180 cycles of the comparative example, and the maximum value is shown at 4000 ppm. If added more than this, lattice corrosion due to sodium sulfate increases, so the optimum amount of sodium in the chemical conversion solution is preferably 300 to 4000 ppm. In addition, other alkali metals and alkaline earth metals were also verified, and similar results were obtained. Therefore, it can be seen that if the alkali metal or alkaline earth metal is contained in the chemical conversion liquid after the chemical conversion is 300 to 4000 ppm, the life performance is improved. Moreover, the effect was the same even if one kind of alkali metal or alkaline earth metal was used, or a plurality of mixed states.

  FIG. 3 shows the relationship between the content of bismuth (Bi) added to the positive electrode current collector and the number of cycles of heavy load life. A Bi amount of 30 or more exceeds 180 cycles of the comparative example, and a maximum value is shown at 150 ppm. When the content is 150 ppm or more, the maintenance-free performance is deteriorated, so the amount of Bi contained in the positive electrode current collector is desirably 30 to 150 ppm. In addition, the same tendency is shown even when Group 5 elements other than Bi, As and Sb, and Group 6 elements Se and Te are used. When a certain amount of group 5 or group 6 element is present in the positive electrode current collector, the lead dioxide produced at the lattice-active material interface is considered to produce stable α-PbO2 or more stable β-PbO2. Thereby, when deep discharge is repeated, the discharge of the active material at the lattice-active material interface can be suppressed, and the early capacity reduction can be suppressed.

  FIG. 4 shows the relationship between the amount of electricity applied, which is the ratio of the amount of energized electricity during formation with respect to the theoretical capacity, and the number of cycles of heavy load life. When the applied amount is 160% or less, it exceeds 180 cycles of the comparative example, and the maximum value is shown at about 120%, and the number of cycles gradually decreases as the applied amount decreases. In addition, since a capacity | capacitance falls significantly when the applied amount of electricity is 90% or less, the applied amount of electricity is desirably 90 to 160%. This is because the amount of stable α-PbO 2 that is responsible for suppressing early capacity reduction is reduced and the cycle characteristics are deteriorated due to an increase in the amount of power applied.

It is a figure which shows the capacity | capacitance change in the heavy load life test of a comparative example and Embodiment 1. FIG. It is the figure which showed the relationship between the amount of Na in the chemical liquid after chemical conversion, and the cycle number of heavy load lifetime. It is the figure which showed the relationship between Bi content in a positive electrode electrical power collector, and the cycle number of heavy load lifetime. It is the figure which showed the relationship between the amount of electric charges, and the cycle number of heavy load lifetime.

Claims (5)

A lead storage battery using an unformed electrode plate made of a lead-calcium alloy current collector, wherein at least one alkali metal or alkaline earth metal is added to the chemical conversion solution for conversion. The lead acid battery according to claim 1, wherein the chemical conversion liquid after the chemical conversion contains 300 to 4000 ppm of alkali metal or alkaline earth metal. The lead acid battery according to claim 1 or 2, wherein the current collector of the lead acid battery contains at least one element of As, Sb, Bi (Group 5), Se, or Te (Group 6). The lead acid battery according to claim 3, wherein the total amount of elements contained in the current collector is 30 to 150 ppm. The lead storage battery according to any one of claims 1 to 4, wherein the amount of electricity supplied during conversion is 90 to 160% of a theoretical capacity of a positive electrode active material of the lead storage battery.

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