JP5494012B2 - Battery case formation method for lead acid battery - Google Patents

Description

  The present invention relates to a battery case formation method for a lead storage battery used as an uninterruptible power supply, a power supply for starting an engine of an automobile, and the like.

Lead acid batteries are used for various purposes as an inexpensive and highly reliable battery, as an uninterruptible power supply, a power source for starting an automobile engine, and the like. In general, lead storage batteries used in these applications are subjected to an electrode plate forming process by a battery case forming method that is inexpensive to manufacture and easy to mass-produce.
Recently, improvement in productivity has been demanded by shortening the manufacturing time. In addition, for the purpose of protecting the global environment, it is also strongly required to reduce carbon dioxide (CO ₂ ) emissions by reducing the amount of charged electricity (Ah) during battery case formation.

As a method of reducing the amount of charged electricity (Ah) during battery case formation, the battery voltage (V) during formation is measured, a short discharge operation is applied before the reversal, and the battery voltage (V) is converted. A method of reducing the amount of charged electricity (Ah) by improving the formation efficiency by reducing the formation current (A) after the extreme has been studied (for example, Patent Document 1).
In addition, charging and discharging are repeated with a predetermined current pattern at the time of battery case formation, and the current value (A) at the time of formation is changed in two or more stages, thereby improving the formation efficiency and reducing the amount of charge electricity (Ah). A method has also been studied (for example, Patent Document 2).

Japanese Patent No. 3018406 JP 2002-63895 A

  However, in the method of Patent Document 1 as described above, the battery voltage (V) is measured for each lead storage battery having different performance (for example, lead storage batteries having different capacities (Ah)), and discharging is performed before switching the polarity. Therefore, there is a problem that facilities for forming the battery case are complicated. Further, when the charging current is decreased after the battery voltage is reversed, the ratio of lead sulfate to the progress of lead dioxide conversion of the active material is increased, and lead sulfate is likely to remain after the formation of the battery case. Thereby, there exists a problem that the discharge capacity (Ah) of the lead storage battery immediately after battery case formation may not be enough. This problem is conspicuous in a large electrode plate, a thick electrode plate, or an electrode plate containing an active material having a large particle diameter, which has poor conversion efficiency.

  Further, even when the method of Patent Document 2 is used, the ratio of lead sulfate to the progress of lead dioxide conversion of the active material can be reduced by simply reducing the charge current after the charge / discharge repetition process compared to before charge / discharge. And lead sulfate tends to remain after the formation of the battery case. Thereby, there exists a problem that the discharge capacity (Ah) of the lead storage battery immediately after battery case formation may not be enough. This problem is conspicuous in a large electrode plate, a thick electrode plate, or an electrode plate containing an active material having a large particle diameter, which has poor conversion efficiency. In addition, the charging current is increased at the end of the formation, but this is to shorten the formation time.If the current at the start of the formation is increased, the formation will be completed in a short time. There is also a statement that is expensive.

  The object of the present invention is to solve the above-mentioned problems, and can improve the formation efficiency with a small amount of charged electricity (Ah) without complicating the battery tank formation equipment, immediately after the battery tank formation. It is providing the battery case formation method which can fully obtain the discharge capacity (Ah).

  In order to solve the above-described problem, the battery case forming method for a lead storage battery according to the present invention is a cycle in which the charge current is changed in two or more stages during charging from the start of formation to the end of formation. The cycle is repeated as described above (claim 1).

Preferably, the charging current is changed in two or more steps between a current value larger than 8 mA per 1 g of the positive electrode active material before battery case formation and a current value smaller than 8 mA per 1 g of the positive electrode active material before battery case formation. Item 2). Preferably, the operation for reducing the magnitude of the charging current in three stages is defined as one cycle (Claim 3), and the maximum current of the charging current changed in two or more stages is at least three times the minimum current ( Claim 4).
In addition, it is preferable to incorporate two or more discharge operations during charging from the start of formation to the end of formation (Claim 5).

In the battery case formation method according to the present invention, during the charge from the start of formation to the end of formation, the cycle is repeated with an operation of changing the charging current in two or more stages as one cycle. Thereby, especially with respect to the amount of active material of a positive electrode plate, lead dioxide conversion of an active material can be advanced with a small amount of charge electricity (Ah), and chemical conversion efficiency can be improved. Moreover, lead dioxide conversion of an active material can be progressed uniformly, there is little residue of lead sulfate after battery case formation, and the discharge capacity (Ah) of the lead storage battery immediately after battery case formation can be made high.
Moreover, since battery voltage etc. are not measured during battery case formation, an installation is not complicated.

It is the schematic of the electric current pattern of charge of the battery case chemical | medical agent which concerns on Example 3. FIG. It is the schematic of the electric current pattern of the charging of a battery case formation which concerns on Example 8. FIG. It is the schematic of the electric current pattern of charge and discharge of battery case formation which concerns on Example 11. FIG. It is the schematic of the electric current pattern of the charging of battery case formation which concerns on the comparative example 1. FIG. It is the schematic of the electric current pattern of the charging of battery case formation which concerns on the comparative example 2. FIG. It is the schematic of the electric current pattern of the charging of battery case formation which concerns on the comparative example 3. FIG. It is the schematic of the electric current pattern of the charging of battery case formation which concerns on the comparative example 4. FIG.

  The lead-acid battery described in the present invention is not particularly limited, but a lead-acid battery in which a non-active material is supported on a lead or lead alloy current collector is used. Can do. Then, after the electrode plate is immersed in the electrolytic solution, the battery case is formed.

As the electrode plate, a clad type, a paste type or a tuddle type can be used, but a paste type which has good manufacturability and can easily increase the electrode plate area is preferable.
The electrolytic solution is not particularly limited, but diluted sulfuric acid with purified water and adjusted to a concentration of about 30% by mass concentration to an appropriate concentration considering the battery capacity, life, etc. ( In some cases, additives such as magnesium sulfate and silica gel may be added in accordance with the characteristics) and then the liquid is injected.

  The current collector is made of lead as a main raw material, and tin, calcium, antimony, or the like can be used as the alloy material. Among them, it is preferable to use both tin and calcium. This is because when calcium is added, the rate of self-discharge can be reduced, and the addition of tin suppresses the susceptibility to bone corrosion, which is a problem when calcium is added. It is because it can do.

  In the paste-type electrode plate, it is necessary to support a paste-like active material on the current collector, but in this operation, the paste-like active material is pushed out against the current collector under pressure, and then It can be carried out by further pressing using a roller.

  The active material is not particularly limited, but kneaded lead powder containing lead monoxide, water, sulfuric acid, etc. (cut fiber, carbon powder, lignin, barium sulfate, lead tan, An additive such as basic lead sulfate may be added).

  At this time, the positive electrode active material can be made porous by forming a basic lead sulfate skeleton having a large particle size or by adding graphite, so that a large amount of sulfuric acid can be contained in the electrode plate. A positive electrode active material with high utilization can be obtained.

The positive electrode active material before battery case formation is mainly composed of lead monoxide (PbO), lead sulfate (PbSO ₄ ), and basic lead sulfate. When dilute sulfuric acid as an electrolyte is added, lead monoxide and When a part of basic lead sulfate is converted to lead sulfate, and then formed into a battery case, lead monoxide, lead sulfate, and basic lead sulfate react with water (oxygen) to become lead dioxide (PbO ₂ ).

Since the electrolytic solution of the lead storage battery is an aqueous solution system, the decomposition reaction of water is promoted as the positive electrode potential increases, particularly in the positive electrode chemical conversion reaction. For this reason, in the second half of the chemical conversion, conversion of the active material to lead dioxide is greatly suppressed. In addition, in the case of battery case formation, it must be formed with a high electrolyte specific gravity. For this reason, the active material is easily converted to lead sulfate, and the progress of conversion to lead dioxide is hindered. As a countermeasure, it is necessary to promote lead dioxide conversion by giving an excessive amount of charged electricity. At this time, when basic lead sulfate having a large particle size (for example, about 50 μm) is generated in the positive electrode unactivated active material before battery case formation, the basic lead sulfate particles have a small specific surface area and are electrolyzed. Small contact area with liquid. Therefore, in the process of electrodeposition container formation, inside the crystal of a basic lead sulfate does not react with sufficient water, it tends to produce an intermediate oxide (PbO _x). As a countermeasure, in order to convert basic lead sulfate having a large particle size into lead dioxide, the chemical conversion time is lengthened and an excessive amount of charge electricity is required.

  In the battery case formation method according to the present invention, during the charge from the start of formation to the end of formation, the cycle is repeated with an operation of changing the charging current in two or more stages as one cycle. Thereby, the inside of the crystal | crystallization of basic lead sulfate can be made porous, and chemical conversion efficiency can be improved.

  In the case of charging with a charging current (hereinafter referred to as a small current) smaller than 8 mA (hereinafter referred to as “mA / g”) per 1 g of the positive electrode active material before the battery formation, Since oxidation proceeds to lead sulfate inside the lead crystal, it can be made porous. However, the ability to oxidize lead sulfate, which is a nonconductor, is small and lead sulfate remains. These effects are more conspicuous as the current is smaller. In the present invention, the positive electrode active material before the formation of the battery case is a lead compound that directly participates in the battery reaction, such as lead powder containing lead monoxide, red lead, basic lead sulfate and the like.

On the other hand, charging with a charging current (hereinafter, referred to as a large current) with a charging current larger than 8 mA / g at the time of battery case formation has an effect of oxidizing lead sulfate and has an effect of suppressing the remaining lead sulfate. However, the inside of the crystal of basic lead sulfate is oxidized before being converted to lead sulfate, the surface of the particles becomes dense, and the intermediate oxide (PbO _x ) tends to remain inside. These effects become more significant as the current increases.

From the above, it is possible to increase the lead dioxide and suppress the residual of intermediate oxide (PbO _x ) and lead sulfate by combining the large current and the small current to form one cycle and repeating the cycle. Thereby, the inside of the crystal | crystallization of basic lead sulfate can be made porous, and chemical conversion efficiency can be improved. In particular, the effect can be remarkably confirmed for basic lead sulfate having a large particle size.
By making the number of repetitions 2 times or more, lead dioxide inside the crystal of basic lead sulfate can be ensured.

At this time, as described above, intermediate oxide (PbO _x ) remains when charged with a large current, and lead sulfate remains when charged with a small current. For this reason, it is preferable to combine a charging current between a large current and a small current (hereinafter referred to as a medium current) to change the charging current in three or more stages. Thus, it is possible to promote dioxide lead content, it is possible to suppress the remaining intermediate oxide (PbO _x) and lead sulfate.

In addition, it is more effective to reduce the charging current and gradually promote the lead dioxide conversion so that the electrolysis reaction of water is less likely to occur while lowering the potential of the positive electrode. It is preferable that the operation to be reduced more than one cycle.
By making the number of repetitions 2 times or more, conversion of lead dioxide inside the crystal of basic lead sulfate can be promoted.

  Furthermore, it is preferable that the maximum current is 3 times or more the minimum current because the chemical conversion efficiency can be sufficiently improved. At this time, the maximum current is preferably 15 mA / g or more, and the minimum current is preferably 5 mA / g or less. Thereby, the lead dioxide conversion inside the crystal of basic lead sulfate can be ensured. Here, the maximum current is the maximum value of the charging current changed during charging from the start of conversion to the end of conversion, and the minimum current is changed during charging from the start of formation to the end of conversion. This is the minimum charging current.

Two or more discharging operations can be incorporated during the charging operation in the battery case formation. Thereby, the lead dioxide inside the crystal of basic lead sulfate can be further promoted.
By incorporating a discharge operation during the formation of the battery case, the electrolyte in the battery moves, and the concentration of the electrolyte changes, and the gas generated during the formation can be smoothly extracted from the electrolyte into the air. The uneven concentration of the electrolytic solution is eliminated.

  By incorporating a discharge operation during the formation of the battery case, the surface of the basic lead sulfate crystal can be converted to lead sulfate and then the surface can be made porous by converting to lead dioxide. Then, diffusion of the electrolyte solution into the basic lead sulfate crystal can be promoted, and lead dioxide conversion inside the basic lead sulfate crystal can be promoted. Thereby, water can be supplied to the inside of the crystal | crystallization of basic lead sulfate, and chemical conversion efficiency can be improved. In particular, the effect can be remarkably confirmed for basic lead sulfate having a large particle size.

  Moreover, the discharge capacity immediately after battery case formation can fully be obtained by performing discharge operation 3 times or more. At this time, since the capacity of the lead storage battery gradually increases during the formation of the battery case, the discharge capacity at the second time than the first time and the discharge capacity at the third time from the second time are set in accordance with the capacity that can be discharged at that time. The effect can be sufficiently obtained by gradually increasing the amount.

Below, the form for implementing this invention is demonstrated in detail using the Example which forms a battery case in a control valve type lead acid battery.
1. Manufacture and test conditions of a control valve type lead acid battery A control valve type lead acid battery was manufactured under the manufacturing conditions conventionally used. That is, after a lead-calcium-tin alloy current collector is filled with a paste-like active material, aging and drying are performed to produce an unformed positive electrode plate and negative electrode plate. These paste-type positive electrode plate and paste-type negative electrode plate are 125 mm in length and 110 mm in width, and have a substantially rectangular plate shape.

Paste-type positive electrode plate Lead alloy with 1.6% by mass of tin and 0.08% by mass of calcium added to lead to make the entire mixture 100% by mass was melted, and a current collector was produced by gravity casting. . After adding 0.1 mass% of polyester fibers to the current collector and mixing the mass of lead powder with lead monoxide as a main component, and then kneading by adding water: 12 mass% Further, a pasty active material kneaded again with 16% by mass of diluted sulfuric acid having a specific gravity of 1.26 was filled. After the filling, aging was performed by first standing for 6 hours in an atmosphere at a temperature of 80 ° C. and a relative humidity of 96%, followed by secondary standing for 30 hours in an atmosphere at a temperature of 60 ° C. and a relative humidity of 60%. By drying, a positive electrode plate containing basic lead sulfate having a large particle size and poor conversion efficiency was obtained.

Paste-type negative electrode plate Lead alloy prepared by adding 0.2% by mass of tin and 0.1% by mass of calcium to lead to make the entire mixture 100% by mass is melted, and a current collector is prepared by gravity casting. did. For this current collector, carbon powder such as lignin: 0.2% by mass, barium sulfate: 0.1% by mass, ordinary commercially available graphite, etc. with respect to the mass of lead powder mainly composed of lead monoxide : 0.2 mass%, polyester fiber: 0.1 mass% is added and mixed. Next, after adding 12% by mass of water and kneading, the paste-like active material kneaded again by adding 13% by mass of diluted sulfuric acid having a specific gravity of 1.26 was filled. After the filling, it was aged and dried to obtain a negative electrode plate.

  Using 10 paste-type positive electrode plates and 11 paste-type negative electrode plates, each positive and negative electrode plate is laminated via a separator (for example, a glass fiber nonwoven fabric retainer), and each positive electrode plate and each negative electrode plate are laminated. An electrode group is manufactured by welding. The amount of the active material of the positive electrode before the battery case is 1430 g. And 3 sets of manufactured electrode plate groups are accommodated in a battery case, are connected in series (3 cells are connected in series), and a lid is attached. Then, a predetermined amount of dilute sulfuric acid electrolyte is poured into each cell so that the finished specific gravity after the formation of the battery case is 1.28.

  Four hours after injecting the dilute sulfuric acid electrolyte into each cell, a battery case was formed in accordance with the specifications of each example described later, and a 6V-100Ah (however, 10 hour rate discharge capacity) control valve type lead storage battery was manufactured. .

Example 1
FIG. 1 shows a schematic diagram of a charging current pattern when an operation of reducing the charging current in two stages during the charging from the start of formation to the end of formation as one cycle is repeated. FIG. 1 shows a charging current pattern when the number of repetitions is 6 (Example 3).
In Example 1, the operation of charging for 10.20 hours at a charging current of 17.5 mA / g and then charging for 18.95 hours at a charging current of 3.5 mA / g was taken as one cycle, and this was repeated for two cycles. Conversion was performed.
In this embodiment, each charging time is set so that the total amount of electricity to be charged is 700 Ah and the required time is 58.3 hours. The maximum current is five times the minimum current.

(Example 2)
In Example 1, charging was performed for 6.80 hours at a charging current of 17.5 mA / g, and then charging was performed for 12.63 hours at a charging current of 3.5 mA / g as one cycle. Battery case formation was carried out in the same manner as in Example 1.

(Example 3)
In Example 1, the operation of charging for 3.40 hours at a charging current of 17.5 mA / g and then charging for 6.32 hours at a charging current of 3.5 mA / g as one cycle was repeated except that this was repeated for 6 cycles. Battery case formation was carried out in the same manner as in Example 1.

(Example 4)
In Example 1, the operation of charging for 1.70 hours at a charging current of 17.5 mA / g and then charging for 3.16 hours at a charging current of 3.5 mA / g is taken as one cycle, and this is repeated for 12 cycles. Battery case formation was carried out in the same manner as in Example 1.

(Example 5)
In Example 1, charging is performed for 1.13 hours at a charging current of 17.5 mA / g, then charging for 2.11 hours at a charging current of 3.5 mA / g is set as one cycle, and this is repeated for 18 cycles. Battery case formation was carried out in the same manner as in Example 1.

(Example 6)
FIG. 2 shows a schematic diagram of a charging current pattern when an operation of reducing the charging current in three stages during the charging from the start of formation to the end of formation as one cycle is repeated. FIG. 2 shows a charging current pattern when the number of repetitions is 6 (Example 8).
In Example 6, the battery was charged at a charging current of 17.5 mA / g for 6.85 hours, then charged at a charging current of 8.4 mA / g for 9.55 hours, and further charged at a charging current of 3.5 mA / g for 12.75 hours. The operation to be performed was defined as one cycle, and this was repeated for two cycles to form a battery case.
In this embodiment, each charging time is set so that the total amount of electricity to be charged is 700 Ah and the required time is 58.3 hours. The maximum current is five times the minimum current.

(Example 7)
In Example 6, the battery was charged at a charging current of 17.5 mA / g for 4.57 hours, then charged at a charging current of 8.4 mA / g for 6.37 hours, and further charged at a charging current of 3.5 mA / g for 8.50 hours. The battery case was formed in the same manner as in Example 6 except that the operation to be performed was one cycle and this was repeated three cycles.

(Example 8)
In Example 6, the battery was charged at a charging current of 17.5 mA / g for 2.28 hours, then charged at a charging current of 8.4 mA / g for 3.18 hours, and further charged at a charging current of 3.5 mA / g for 4.25 hours. The battery case was formed in the same manner as in Example 6 except that the operation to be performed was one cycle and this was repeated for 6 cycles.

Example 9
In Example 6, the battery was charged at a charging current of 17.5 mA / g for 1.14 hours, then charged at a charging current of 8.4 mA / g for 1.59 hours, and further charged at a charging current of 3.5 mA / g for 2.13 hours. The battery case was formed in the same manner as in Example 6 except that the operation to be performed was one cycle and this was repeated 12 cycles.

(Example 10)
In Example 6, the battery was charged at a charging current of 17.5 mA / g for 0.76 hours, then charged at a charging current of 8.4 mA / g for 1.06 hours, and further charged at a charging current of 3.5 mA / g for 1.42 hours. The battery case was formed in the same manner as in Example 6 except that the operation to be performed was one cycle and this was repeated 18 cycles.

(Example 11)
In Example 8, the schematic of the charging / discharging current pattern at the time of incorporating discharge operation after the 2nd cycle and the 4th cycle is shown in FIG.
In Example 11, the battery was charged at a charging current of 17.5 mA / g for 2.76 hours, then charged at a charging current of 8.4 mA / g for 3.04 hours, and further charged at a charging current of 3.5 mA / g for 3.42 hours. The operation to be performed was one cycle. And after repeating the said cycle 2 cycles, 1 hour of discharge operation is incorporated at 8.4 mA / g. Next, after repeating the above cycle for 2 cycles, a discharge operation of 2 hours at 8.4 mA / g is incorporated. Further, the battery cycle was formed by repeating the cycle two cycles.

In other words, two discharge operations are incorporated during the charging from the start of formation to the end of formation, and the amount of discharge electricity by the discharge operation is increased from the first time to the second time.
In this embodiment, the total amount of electricity to be charged is set to 700 Ah and the required time is set to 58.3 hours. Here, since the discharge current at the time of the discharge operation is used as a regenerative current for the formation of different battery cases, the amount of electricity to be charged (Ah) is calculated from the total amount of charge electricity to the discharge electricity at the time of the discharge operation. It is calculated by subtracting the amount. The maximum current is five times the minimum current.

(Comparative Example 1)
FIG. 4 shows a schematic diagram of a charging current pattern in which the charging current is constant during charging from the start of formation to the end of formation.
From the start of chemical conversion to the end of chemical conversion, the battery case was formed by continuous charging at a charging current of 8.4 mA / g for 76.7 hours.
The total amount of electricity charged by this battery case forming method is 920 Ah, and the required time is 76.7 hours.

(Comparative Example 2)
FIG. 5 shows a schematic diagram of a charging current pattern in which the charging current is the same and the charging time is shortened in Comparative Example 1.
From the start of chemical conversion to the end of chemical conversion, a battery case was formed by continuous charging at a charging current of 8.4 mA / g for 58.3 hours.
The total amount of electricity charged by this battery case forming method is 700 Ah, and the required time is 58.3 hours.

(Comparative Example 3)
FIG. 6 shows a schematic diagram of a charging current pattern when the operation of reducing the charging current in two stages during the charging from the start of the formation to the end of the formation is regarded as one cycle and this is carried out for one cycle.
From the start of conversion, the battery was charged for 20.4 hours at a charging current of 17.5 mA / g, and then charged for 37.9 hours at a charging current of 3.5 mA / g to form a battery case.
The total amount of electricity charged by this battery case forming method is 700 Ah, and the required time is 58.3 hours.

(Comparative Example 4)
FIG. 7 shows a schematic diagram of a charging current pattern when an operation for reducing the charging current in three stages during the charging from the start of formation to the end of formation is performed as one cycle.
From the start of conversion, after charging for 13.7 hours at a charge current of 17.5 mA / g, charge for 19.1 hours at a charge current of 8.4 mA / g, and further charge for 25.5 hours at a charge current of 3.5 mA / g. A battery case was formed.
The amount of electricity charged by this battery case forming method is 700 Ah, and the required time is 58.3 hours.

  After the battery formation of the control valve type lead-acid battery in each of the above examples is completed, the battery is left to cool for 24 hours and then cooled, and then discharged at 20 A (a discharge current at a 5-hour rate). Ah) was measured. The results are shown in Table 1 together with the charging conditions for battery case formation.

  As is clear from Table 1, each Example can reduce the total amount of charged electricity (Ah) by about 24% compared to Comparative Example 1, and while reducing the time required for battery case formation by 18.4 hours, A sufficient discharge capacity immediately after the formation of the battery case can be secured.

  As is clear from the comparison between Comparative Example 2 and Comparative Example 1, when the charging current is constant, if the total charge electricity amount (Ah) is simply reduced, the discharge capacity immediately after the formation of the battery case is reduced. . In addition, as is clear from the comparison between Comparative Examples 3 and 4 and each example, the operation of changing the charging current in two or more stages is defined as one cycle, and when this is performed only for one cycle, A sufficient discharge capacity cannot be ensured.

  As is clear from the comparison between Examples 1 to 5 and Examples 6 to 10, the operation of changing the charging current in two or more stages is set as one cycle, and when the cycle is repeated, the number of repetitions increases, The discharge capacity immediately after battery case formation is improved. In addition, it is preferable that the number of repetitions of the cycle is 6 cycles or more because a sufficient discharge capacity can be ensured immediately after the formation of the battery case.

  Furthermore, as is clear from the comparison between Example 11 and Example 8, when two or more discharge operations were incorporated during the charge from the start of formation to the end of formation, the discharge capacity immediately after the formation of the battery case was further increased. Can be improved.

  In each of the embodiments according to the present invention, even if the amount of charge electricity (Ah) is reduced, the reason why the discharge capacity (Ah) immediately after the formation of the battery case can be secured is to charge evenly to the active material reaching the inside of the electrode plate. It is thought that this is because

  Moreover, the active material of the positive electrode plate after battery case formation of each Example was extract | collected, the amount of lead sulfate remaining in the active material was measured, and the progress of chemical conversion reaction was confirmed. If the amount of the remaining lead sulfate is small, the chemical conversion reaction proceeds efficiently.

The method for measuring the amount of remaining lead sulfate is as follows.
An aqueous solution containing nitric acid and hydrogen peroxide is added to the positive electrode active material after battery case formation and subjected to ultrasonic treatment for 1 hour. That is, 80 ml of an aqueous solution containing nitric acid and hydrogen peroxide (containing 60 mass% nitric acid and 31 mass% hydrogen peroxide) is collected, and 1 g of the positive electrode active material is added to 20 ml of an aqueous solution diluted to 1 liter with distilled water. This is subjected to ultrasonic treatment, filtered through 5C filter paper, and the filter paper solution is sufficiently washed away with distilled water. The weight of the remaining lead sulfate is measured by thoroughly burning and eliminating the filter paper containing the residue in the crucible.

As shown in Table 2, each example applies the battery case formation method according to the present invention, so that the amount of lead sulfate remaining in the positive electrode active material after battery case formation is reduced, and the chemical conversion reaction is efficiently performed. You can see that it has progressed. In particular, in Examples 3 to 5 and 8 to 11, the chemical reaction proceeds efficiently. Although detailed experimental results were omitted, the same results as described above were obtained for the amount of the intermediate product (PbO _x ) remaining.
In each example, no difference was observed in the residual amount of lead sulfate in the negative electrode active material.

  Although detailed experimental results were omitted, in the charging current pattern in which the operation of reducing the charging current to four or more steps was repeated from the start of the formation to the end of the formation, the operation of reducing the number of steps to three steps was repeated. The same effect as the case was shown.

  In the above-described embodiments, the battery case forming method for the control valve type lead storage battery has been described in detail, but it can be similarly applied to the battery case forming method for a liquid type lead storage battery such as an automotive lead storage battery. . In addition, although it described about the improvement of the chemical conversion efficiency in the state which produced | generated the big particle | grains which a chemical conversion reaction does not advance easily, it is effective similarly in a small particle | grain, and a battery case chemical conversion method can be applied.

  INDUSTRIAL APPLICATION This invention can be used for the battery case formation method of the lead storage battery currently used for the uninterruptible power supply, the battery for motor vehicles, etc.

Claims (5)

In a battery case formation method for a lead storage battery,
A battery case forming method for a lead storage battery, characterized in that, during charging from the start of formation to the end of formation, an operation for changing the magnitude of the charging current in two or more steps is repeated as one cycle.   The charging current is changed in two or more steps between a current value larger than 8 mA per 1 g of the positive electrode active material before battery case formation and a current value smaller than 8 mA per 1 g of the positive electrode active material before battery case formation. The battery case formation method of the lead storage battery of Claim 1.   The battery case formation of the lead storage battery according to claim 1 or 2, wherein the cycle is repeated with an operation of reducing the magnitude of the charging current in three steps as one cycle during charging from the start of formation to the end of formation. Method.   The battery forming method for a lead storage battery according to any one of claims 1 to 3, wherein the maximum current of the charging current changed in two or more stages is three times or more of the minimum current.   5. The battery case forming method for a lead storage battery according to claim 1, wherein two or more discharge operations are incorporated during charging from the start of formation to the end of formation.

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