JP5659484B2 - Battery case formation method for lead acid battery - Google Patents

Description

  The present invention relates to a battery case forming 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) at the time of battery case formation, the battery voltage (V) is measured during the formation, and a short discharge operation is performed before the reversal to improve the formation efficiency. A method for reducing the amount of charged electricity (Ah) has been studied (for example, Patent Document 1).

  In addition, by repeating a predetermined current pattern for charging and discharging during battery case formation, and changing the current value (A) during formation in two or more steps, the formation efficiency is improved and the amount of charged electricity (Ah) is reduced. 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, even when the method of Patent Document 2 as described above is used, the improvement in chemical conversion efficiency is not sufficient, and as a result, the discharge capacity (Ah) immediately after battery case formation may not be sufficient. There is.

  The object of the present invention is to solve the above-described problems, and the process of forming a battery case is easy, and the formation efficiency can be improved with a small amount of charged electricity (Ah). It is to provide a battery case forming method capable of sufficiently obtaining a capacity (Ah).

In order to solve the above-described problems, the present invention is characterized in that a discharge operation is incorporated when a lead-acid battery is formed into a battery case. That is, according to the first aspect of the present invention, in the battery case formation method for a lead-acid battery, two or more discharge operations are incorporated during charging from the start of formation to the end of formation, and the amount of discharge electricity by the discharge operation is 2 from the first time. Gradually increase after the first round . In addition, in each charge performed from the start of formation to the first discharge operation, from the end of one discharge operation to the start of the next discharge operation, and from the end of the last discharge operation to the end of formation, the charging current is 3 It is characterized by repeating the cycle by setting the operation to decrease in stages as one cycle .
By incorporating the discharge operation during the formation, the electrolytic solution in the battery moves, and the concentration of the electrolytic solution changes, and the gas generated during the formation can be smoothly extracted from the electrolytic solution into the air. The uneven density is eliminated. By repeating the cycle with the operation of reducing the charging current in three stages as one cycle, the charging reaction can be made to proceed evenly with respect to the active material of the positive electrode plate in particular, and the discharge capacity of the lead storage battery immediately after the formation of the battery case Can be further increased.

  According to a second aspect of the present invention, in the first aspect of the invention, three discharge operations are incorporated during charging from the start of formation to the end of formation, and the amount of electricity discharged by the discharge operation is changed from the first to the third. It is characterized by an increase.

In each of the above inventions, in order to effectively use the discharge current of the discharge operation, the invention of claim 3 is characterized in that the discharge current in the discharge operation is used for forming a battery of different systems.

When the battery case forming method according to the present invention is used, the battery case forming process is easy, the discharge operation is incorporated during the formation, and the discharge current is also reused in the battery case forming, so that the charging electric power is small. The chemical conversion efficiency can be improved by the amount (Ah), and the discharge capacity (Ah) of the lead storage battery immediately after battery case formation can be increased. In each step of the conductive container formation, by repeating the cycle of operation to reduce the charge current to the three stages as one cycle, it is possible to proceed evenly charging reaction, especially for the active material of the positive plate, the container The discharge capacity of the lead storage battery immediately after formation can be further increased.

It is the schematic of the electric current pattern of battery case formation which concerns on the reference example 1, and the electric current pattern of discharge. It is the schematic of the electric current pattern of charge and discharge of battery case formation which concerns on the reference example 2. FIG. It is the schematic of the electric current pattern of the battery case chemical formation which concerns on Example 1 , and the electric current pattern of discharge. It is the schematic of the electric current pattern of charge and discharge of the battery case formation which concerns on Example 2. FIG. It is the schematic of the electric current pattern of charge and discharge of the battery case formation which concerns on the comparative example 1. FIG. It is the schematic of the electric current pattern of the battery case chemical formation which concerns on the comparative example 2, and the discharge.

  The lead storage battery described in the present invention is not particularly limited, but a lead plate in which an active material is supported on a current collector made of lead or a lead alloy and immersed in an electrolytic solution can be used. . 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 etc. according to the characteristics of the positive electrode and negative electrode) The additive may be added in some cases.

  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 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 basic A part of lead sulfate is converted to lead sulfate, and by forming 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 active material before the formation of the battery case, the basic lead sulfate particles have a small specific surface area, The contact area is small. 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, an excessive amount of charged electricity is required.

  In the battery case forming method according to the present invention, the surface of the lead acid battery is made porous by converting it into lead sulfate after incorporating the discharge operation into the lead acid battery at the time of forming the battery case, thereby converting the crystal surface of the basic lead sulfate to lead sulfate. Can be 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.

  By making the discharge operation twice or more, lead dioxide inside the crystal of basic lead sulfate can be ensured. 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.

At this time, between the conversion start until the first discharge operation start, during the period from one discharge operation ends until the start of the next discharge operation, in each charging performed until conversion completion from the last discharge operation ends, the charging current By repeating the cycle with the operation of reducing to three steps as one cycle, the inside of the crystal of basic lead sulfate can be made porous, and the chemical conversion efficiency can be improved.

  Compared to the conventional charging current (hereinafter referred to as medium current), charging with a small charging current (hereinafter referred to as small current) leads to lead sulfate inside the basic lead sulfate crystal compared to the case of medium current. Since the oxidation proceeds while forming, 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.

On the other hand, charging with a large charging current (hereinafter, referred to as a large current) with respect to a medium current has the ability to oxidize lead sulfate and has an effect of suppressing the residual 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, by combining a large current, a medium current, and a small current, lead dioxide can be increased and the residual of intermediate oxide (PbO _x ) and lead sulfate can be suppressed. 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.

Assuming that the same amount of electricity is given when only a large current and a small current are repeated, the proportion of large current and small current increases because there is no medium current, and lead sulfate and intermediate oxide (PbO _x ) It tends to remain. From the above, it is preferable that the operation for reducing the charging current in three stages is one cycle.

  By setting the number of repetitions to 2 times or more, it is possible to ensure lead dioxide conversion inside the crystals of basic lead sulfate, which is preferable.

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 A lead-calcium-tin alloy was melted, and a current collector was prepared by a gravity casting method. This current collector is filled with 0.1% by mass of polyester fiber with respect to the mass of the lead powder containing lead monoxide as a main component, mixed, and then mixed with water and dilute sulfuric acid to knead and paste the active material did. 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 A lead-calcium-tin alloy was melted, and a current collector was produced by a gravity casting method. In this current collector, 0.2% by mass of lignin, 0.1% by mass of barium sulfate, and commercially available carbon powder such as graphite, etc. 2% by mass and 0.1% by mass of polyester fiber were added and mixed, and the paste-like active material kneaded by adding water and dilute sulfuric acid was filled. After the filling, it was aged and dried to obtain a negative electrode plate.

  Ten paste-type positive electrode plates and 11 paste-type negative electrode plates are used, and each positive and negative electrode plate is laminated via a separator (for example, a glass fiber nonwoven fabric retainer). Each is welded to produce an electrode plate group. 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. .

( Reference Example 1)
FIG. 1 shows a schematic diagram of a charge / discharge current pattern in the case where two discharge operations are incorporated during charging from the start of formation to the end of formation.
Charge 24 hours at 10.6A from the start of conversion. Subsequently, a 1 hour discharge operation is incorporated at 20A. Next, charge for 9.6 hours at 10.6 A, and then discharge for 2 hours at 20 A. Finally, a charge / discharge current pattern for charging for 33.6 hours at 10.6 A is shown.
That is, two discharge operations were incorporated during the charge from the start of formation to the end of formation, and the amount of discharge electricity by the discharge operation was increased from the first time to the second time.

  The amount of electricity charged by this battery case forming method is 650 Ah, and the required time is 70 hours. In addition, since the discharge current at the time of the discharge operation is used as a regenerative current for the formation of the battery of different systems, the amount of electricity to be charged (Ah) is calculated from the total amount of charge electricity to the amount of discharge electricity at the time of the discharge operation. Is subtracted. The same applies to the following examples.

( Reference Example 2)
FIG. 2 shows a schematic diagram of a charge / discharge current pattern in the case where three discharge operations are incorporated during charging from the start of formation to the end of formation.
Charge 21.5 hours at 11.8A from the start of conversion. Subsequently, the battery is discharged at 20A for 1 hour and charged at 11.8A for 8.6 hours. Next, the battery is discharged at 20A for 2 hours and charged at 11.8A for 12.9 hours. Further, a charging / discharging current pattern is shown in which discharging is performed at 20 A for 2.5 hours, and finally charging is performed at 11.8 A for 21.5 hours.
That is, three discharge operations were incorporated during charging from the start of formation to the end of formation, and the amount of discharge electricity by the discharge operation was increased from the first to the third.

  The amount of electricity charged by this battery case forming method is 650 Ah, and the required time is 70 hours.

(Example 1 )
In Reference Example 1, from the start of chemical conversion to the start of the first discharge operation (first interval), from the end of the first discharge operation to the start of the second discharge operation (second interval), the second discharge operation FIG. 3 shows a schematic diagram of a charge / discharge current pattern when the cycle is repeated with an operation for reducing the charging current in three stages as one cycle in each charge during the period from the end to the end of conversion (third section).
The operation for reducing the charging current in three stages was charging for 1.1 hours at 28A, then charging for 1.3 hours at 10A, and charging for 2.4 hours at 3A as one cycle. The average charging current for one cycle is 10.6A. The one cycle is charged 5 times in the first interval, twice in the second interval, and 7 times in the third interval.

  The amount of electricity charged by this battery case forming method is 650 Ah, and the required time is 70 hours.

(Example 2 )
In Reference Example 2, from the start of chemical conversion to the start of the first discharge operation (first section), from the end of the first discharge operation to the start of the second discharge operation (second section), the second discharge operation An operation for reducing the charging current in three stages in each charge from the end to the start of the third discharge operation (third section) and from the end of the third discharge operation to the end of formation (fourth section). FIG. 4 shows a schematic diagram of a charge / discharge current pattern when the cycle is repeated as a cycle.
The operation for reducing the charging current in three steps was charging for 1.1 hours at 28A, then charging for 1.3 hours at 11A, and charging for 1.9 hours at 3A as one cycle. The average charging current for one cycle is 11.8A. The one cycle is charged 5 times in the first interval, twice in the second interval, 3 times in the third interval, and 5 times in the fourth interval.

  The amount of electricity charged by this battery case forming method is 650 Ah, and the required time is 70 hours.

(Comparative Example 1)
FIG. 5 shows a schematic diagram of a charge / discharge current pattern when one discharge operation is incorporated between the start of formation and the end of formation.
From the start of conversion, the battery is charged at 9.7 A for 27 hours. Subsequently, a 1 hour discharge operation is incorporated at 20A. Next, a charging / discharging current pattern for charging at 9.7 A for 64 hours is shown.

  The amount of electricity charged by this battery case forming method is 860 Ah, and the required time is 92 hours.

(Comparative Example 2)
In the comparative example 1, the schematic of the charging / discharging electric current pattern which shortened the charge time after discharge operation is shown in FIG.
From the start of conversion, the battery is charged at 9.7 A for 27 hours. Subsequently, a 1 hour discharge operation is incorporated at 20A. Next, a charge / discharge current pattern for charging for 42 hours at 9.7 A is shown.

  The amount of electricity charged by this battery case forming method is 650 Ah, and the required time is 70 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 can be seen from Table 1, each example shortened the time required for battery case formation by 22 hours and reduced the amount of charged electricity (Ah) by about 25% as compared with Comparative Example 1, immediately after the battery case formation. A sufficient discharge capacity can be secured.
As can be seen from Comparative Example 2, if the amount of charge electricity (Ah) is simply reduced, the discharge capacity immediately after the formation of the battery case is reduced.

  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

Further, the progress of the chemical conversion reaction was confirmed by collecting the active material of the positive electrode plate after the formation of the battery case in each case and measuring the amount of lead sulfate remaining in the active material. If the amount of the remaining lead sulfate is small, the chemical conversion reaction proceeds efficiently.
The method for measuring the amount of lead sulfate remaining is as follows. An aqueous solution containing nitric acid and hydrogen peroxide is added to the positive electrode active material and subjected to ultrasonic treatment for about 1 hour. That is, 80 ml of an aqueous solution containing nitric acid and hydrogen peroxide (containing 60% by mass of nitric acid and 31% by mass of hydrogen peroxide) is sampled, and 1 g of positive electrode active material is added to about 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 applied 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 reaction is efficiently performed. You can see that it has progressed. In particular, in Examples 1 and 2 , the chemical reaction proceeds efficiently.
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, even if the discharge operation was incorporated four or more times during the period from the start of formation to the end of formation, almost no further effect was observed. Reference Example 2 shows that there is a limit even if the number of incorporation of the discharge operation exceeds 3 times. Further, since the discharging operation is a reaction opposite to the charging reaction, it can be said that increasing the incorporation of the discharging operation is not preferable because there is a problem that the time required for forming the battery case becomes long.

However, in Examples 1 and 2 , in addition to the chemical conversion reaction proceeding efficiently , in each step of battery case formation, the operation of reducing the charging current to three stages is repeated as one cycle, whereby the battery case is repeated. It shows that the discharge capacity of the lead storage battery immediately after formation can be further increased.

  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 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 (3)

In a battery case formation method for a lead storage battery,
Incorporating two or more discharge operations during the charge from the start of formation to the end of formation, and gradually increasing the amount of discharge electricity from the first to the second and subsequent times ,
In each charge performed from the start of formation to the start of the first discharge operation, from the end of one discharge operation to the start of the next discharge operation, and from the end of the last discharge operation to the end of formation, the charging current is 3 A battery case forming method for a lead storage battery, characterized in that the operation to be reduced in stages is set as one cycle and the cycle is repeated . In a battery case formation method for a lead storage battery,
The lead storage battery according to claim 1, wherein three discharge operations are incorporated during charging from the start of conversion to the end of conversion, and the amount of discharge electricity by the discharge operation is increased from the first to the third. Battery case formation method. 3. A battery case forming method for a lead storage battery according to claim 1 or 2 , wherein a discharge current in the discharging operation is used for forming a battery case of a different system .

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