JP2005317398A - Manufacturing method of lead-acid battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide the manufacturing method of a lead-acid battery suppressing self discharge of the lead-acid battery in which container formation is completed, and frequency of supplementary charge during storage is reduced. <P>SOLUTION: The manufacturing method of the lead-acid battery is that the container formation is completed in a discharged state, and then adjustment of an electrolyte is conducted. The discharge depth in discharge conducted in completion of the container formation is set to 1.0-4.0% of the theoretical capacity of a positive active material. The discharge conducted in the completion of the container formation is preferably conducted at current equivalent to 0.4-2.0 CA of the battery. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for producing a lead-acid battery, and more particularly to a method for forming a battery case.

  In the conventional lead-acid battery formation of lead-acid batteries, first, lead powder mainly composed of lead and lead monoxide is kneaded with water and dilute sulfuric acid to create a paste-like active material. This paste-like active material Is filled and held in the current collector. After that, the packed plate filled with the paste active material is aged for the purpose of crystal growth of the active material, improvement of paste strength, increase of chemical bond strength between the lattice surface and the active material, removal of moisture, etc. , Drying to produce an unformed anode plate and cathode plate.

Next, an unformed anode electrode plate and cathode electrode plate that have undergone the aging and drying steps are alternately laminated with a separator interposed therebetween to create an electrode group, and this electrode group is housed in a battery case. If the electrode group is stored in the battery case, the opening of the battery case is sealed except for the electrolyte injection port, and the electrolyte solution is injected from the injection port and continuously energized at a constant current, or the chemical conversion efficiency is improved. For this purpose, the electrode plate is formed by resting or discharging during battery case formation, or by stepwise formation for reducing the current value. When the formation of the battery is completed, the specific gravity and the liquid volume are adjusted so that the electrolyte in the battery has a predetermined electrolyte composition, or the electrolyte in the battery is removed once and the electrolyte with a predetermined specific gravity is re-applied. The method of pouring is taken.
Japanese Patent No. 2964555 Japanese Patent Laid-Open No. 5-151987

  As described above, a lead storage battery in which an electrolytic solution is adjusted after completion of battery case formation is very rarely shipped and used immediately, and is generally left for several days to several weeks before shipment. During standing, the specific gravity and voltage of the electrolyte decrease due to self-discharge. For this reason, lead storage batteries that have been left for a predetermined period or longer need to be charged at the time of shipment to maintain a normal electrolyte specific gravity and voltage.

The self-discharge of the battery after the formation of the battery is completed is that PbO ₂ + H ₂ SO ₄ → PbSO ₄ + H ₂ O + 1 / 2O in which the positive electrode active material directly reacts with the electrolyte.
And Pb + H ₂ SO ₄ → PbSO ₄ + H _{2 in} which the negative electrode active material reacts directly with the electrolytic solution
PbO ₂ + H ₂ SO ₄ + Pb → 2PbSO ₄ + 2H ₂ O resulting from the reaction between the lattice and the active material
Is considered the main reaction.

The active material immediately after the formation of the battery is not yet sufficiently crystallized, and there are many fine crystals on the active material surface, and the active material has a large specific surface area, so it is still chemically unstable. In this state, the positive electrode active material and the negative electrode active material are likely to react directly with the electrolytic solution during standing, and such a state has an important influence on the specific gravity of the electrolytic solution and the decrease in battery voltage.
In particular, in summer and the like, since the ambient temperature of the lead storage battery is high, the chemical reaction rate is fast, the self-discharge reaction during the stand is activated, and the defective rate of the battery performance due to the specific gravity of the electrolyte and the decrease in the battery voltage is reduced. It tends to increase. For this reason, in summer, there is also a problem that the frequency of performing supplementary charging is increased in order not to cause battery failure.

  This invention solves such a subject, and it aims at providing the manufacturing method of the lead storage battery which suppressed the self-discharge of the lead storage battery which finished battery case formation, and reduced the frequency of the auxiliary charge in storage. To do.

  In order to solve such a problem, the method for manufacturing a lead storage battery according to the present invention is a method for manufacturing a lead storage battery in which the electrolytic solution is adjusted after the formation of the battery case is terminated by discharging. The discharge depth of the discharge performed at the end of the chemical conversion is set to 1.0% to 4.0% with respect to the positive electrode active material theoretical capacity.

  In addition, as for the discharge performed at the time of completion | finish of battery case formation, it is desirable to discharge with the electric current equivalent to 0.4CA thru | or 2.0CA of a battery.

  According to the present invention, by performing discharge at a discharge depth of 1.0% to 4.0% with respect to the theoretical capacity of the positive electrode active material at the end of battery cell formation, the active material surface is still sufficiently immediately after battery cell formation. Fine crystals that have not been crystallized are converted to lead sulfate, and the surface of the active material can be chemically stabilized. This reduces the amount of active material that reacts directly with the electrolyte (sulfuric acid) while the lead-acid battery is left, reducing the specific gravity of the electrolyte and battery failure caused by a decrease in battery voltage. The frequency of charging can be reduced.

  According to the present invention, by performing discharge at a discharge depth of 1.0% to 4.0% of the theoretical capacity of the positive electrode active material at the end of battery cell formation, the specific gravity of the electrolyte is reduced while the lead storage battery is left, and the battery This is an excellent manufacturing method capable of providing a lead storage battery with a small voltage drop and a low incidence of battery failure.

One embodiment of the present invention is shown below.
A paste powder composed mainly of lead and lead monoxide was kneaded with water and dilute sulfuric acid to prepare a paste-like active material, and this paste-like active material was filled and held in a current collector. After that, the paste plate filled with the paste active material is aged for the purpose of crystal growth of the active material, improvement of the paste strength, increase of the chemical bond strength between the lattice surface and the active material, removal of moisture, etc. Then, drying was performed to produce an unformed anode plate and cathode plate.

  Next, an unformed anode electrode plate and cathode electrode plate that have undergone the aging and drying steps are alternately laminated with a separator interposed therebetween to create an electrode group, and this electrode group is housed in a battery case. The opening was sealed except for the electrolyte inlet and the electrolyte was injected from the inlet to assemble a lead-acid battery. The lead storage battery is continuously energized with a constant current, or in order to improve the formation efficiency, the electrode plate is formed by resting or discharging during battery case formation, or by stepwise formation that reduces the current value, and a predetermined battery case formation is performed. Immediately after the discharge, discharge was performed. The discharge was performed at a discharge depth of 1.0% to 4.0% with respect to the theoretical capacity of the positive electrode active material.

The discharge depth of the discharge is set to 1.0% to 4.0% with respect to the theoretical capacity of the positive electrode active material when the discharge depth is larger than 4.0% with respect to the theoretical capacity of the positive electrode active material. This is because too much lead sulfate is formed, and on the contrary, if it is 1.0% or less, the purpose cannot be sufficiently achieved.
If the depth of discharge is larger than 4.0% of the theoretical capacity of the positive electrode active material, too much lead sulfate is generated in the active material as described above, and the initial performance of the battery cannot be fully exhibited. Adversely affect. For this reason, it is preferable that the discharge at the end of battery case formation has a depth of discharge of up to 4.0% with respect to the theoretical capacity of the positive electrode active material.

  Moreover, it is desirable that the discharge performed at the end of the battery case formation is performed with a current corresponding to 0.4 CA to 2.0 CA of the battery. Discharging at a small current equal to or less than the current corresponding to 0.4 CA unfavorably leads to a long battery formation time and a reduction in production efficiency. On the contrary, it is not preferable to perform discharging with a large current corresponding to 2.0 CA or more of the battery because expensive equipment is required for discharging.

When the discharge is completed, adjust the amount of the electrolyte so that the specific gravity of the electrolyte in the battery case is adjusted to a predetermined value, or once remove the electrolyte in the battery case and replace the electrolyte with a predetermined specific gravity. Re-injection was performed to complete the lead-acid battery.
Specific examples are shown below.

An unformed 2V cell with a rated capacity of 28 Ah / 5 HR is prepared, and after pouring a predetermined amount of dilute sulfuric acid with a specific gravity of 1.200 (20 ° C.), the total amount of electricity charged is 200% of the theoretical capacity of the positive electrode active material The battery is formed with the basic pattern of charge-discharge-charge, and the discharge current 28A corresponding to 1CA of the battery is the condition that the discharge depth with respect to the positive electrode active material theoretical capacity is 0% to 20% as shown in Table 1. 1 to 9 was discharged to complete the formation of the battery case. After the formation of the battery case, the electrolyte solution was once drained, and a predetermined amount of dilute sulfuric acid with a specific gravity of 1.290 (20 ° C) was newly injected, and this 2V cell was left in a constant temperature bath at 30 ° C for 4 weeks. The transition of the specific gravity of the electrolyte and the transition of the battery voltage were measured. The measurement results are shown in FIGS.
Similarly, a 5-hour rate discharge test was conducted on a 2V cell subjected to battery formation under the conditions 1 to 9 shown in Table 1 without leaving it, and the results are shown in Table 2.

  From the results shown in FIGS. 1, 2 and Table 1, the specific gravity and voltage drop during discharge is greatest for several days after the start of standing, and thereafter decreases relatively slowly. However, Condition 1 (Example 1-1) to Condition 3 (Example 1-3) and Condition 6 (Comparative Example 1-3) to Condition 9 (Comparative Example 1-) where the depth of discharge is 1.0% or more. 6) is clearly lower than the condition 4 (Comparative Example 1-1) and the condition 5 (Comparative Example 1-2). This result is presumably because the amount of the active material that reacts directly with the electrolytic solution (dilute sulfuric acid) is reduced and chemically stabilized by converting the fine crystals of the active material into lead sulfate in advance.

  In addition, since the specific gravity of the electrolytic solution and the battery voltage are in a correlation, if the specific gravity decreases greatly, the voltage decrease also increases. However, in the conditions 6 (Comparative Example 1-3) to 9 (Comparative Example 1-6) where the depth of discharge is large as shown in Table 2, too much lead sulfate is generated in the active material, and the rated capacity of 28 Ah / A defect below 5HR has occurred. Therefore, the discharge depth is preferably in the range of 1.0% to 4.0% with respect to the theoretical capacity of the positive electrode active material.

Using the same 2V cell as in Example 1, the discharge current at the end of battery case formation was optimized.
The conditions for optimization are 1.0% and 4.0% of the depth of discharge, and the battery case is formed with the discharge current value of the conditions shown in Table 3, and the electrolyte solution has a specific gravity of 1.290 ( (20 ° C.) was replaced with dilute sulfuric acid and left in a constant temperature bath at 30 ° C., and the transition of the specific gravity during the standing and the 5-hour rate discharge were performed. The transition of specific gravity during standing is shown in FIGS. 3 and 4, and the 5-hour rate discharge capacity is shown in Table 4.

  From the results of FIGS. 3 and 4, the degree of specific gravity reduction is smaller than the condition 4 shown in Example 1 in each condition, and the effect is recognized. From the results of Table 4, when the discharge depth is 4.0%, the discharge current value is relatively small under the condition 20 (Comparative Example 2-1) and under the condition 21 (Comparative Example 2-2) is the 5-hour rate discharge capacity. Is below the rated 28Ah. This is because the utilization rate of the active material increases as the discharge current decreases, and it is presumed that lead sulfate has progressed not only to the fine crystals on the surface of the active material but also to the inside. In addition, if the discharge is performed with a very small current, the time for forming the battery case becomes long, and the production efficiency is lowered, which is not preferable. On the contrary, discharging with a large current may require expensive equipment, and the discharging current is most preferably in the current range corresponding to 0.4 CA to 2.0 CA of the batteries of Examples 2-1 to 2-3. .

  As described above, the present invention performs discharge at the final stage of battery case formation, preferably at a current corresponding to 0.4 CA to 2.0 CA of the battery, at a discharge depth of 1.0% to 4.0% of the theoretical capacity of the positive electrode active material. By pre-converting chemically unstable fine crystals to lead sulfate in advance, it is possible to reduce the decrease in the specific gravity of the electrolyte and the battery voltage without deteriorating the initial performance of the battery, and the battery based on the decrease in specific gravity and the voltage decrease. It is possible to reduce performance defects and reduce the frequency of auxiliary charging of stock batteries.

FIG. 1 is a graph showing changes in the specific gravity of the electrolyte while the lead-acid battery is being left. FIG. 2 is a graph showing the transition of voltage while the lead storage battery is left unattended. FIG. 3 is a graph showing the change in the specific gravity of the electrolyte during standing at a discharge depth of 1.0% of the lead storage battery. FIG. 4 is a graph showing the change in the specific gravity of the electrolyte while it is being left at a discharge depth of 4.0% of the lead storage battery.

Claims (2)

  A method for producing a lead-acid battery in which the electrolytic solution is adjusted after battery case formation is terminated by discharge, and the discharge depth of discharge performed at the end of the battery case formation is 1.0% with respect to the theoretical capacity of the positive electrode active material. % To 4.0%, A method for producing a lead-acid battery.   The lead storage battery manufacturing method according to claim 1, wherein the discharge performed at the end of the battery case formation is performed with a current corresponding to 0.4 CA to 2.0 CA of the battery.

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