JP2002231301A - Method of manufacturing granule type sealed lead-acid battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing a granule type sealed lead-acid battery shortening the required manufacturing time. SOLUTION: Electricity is carried in the charging direction through the battery, when an excess electrolyte is exhausted in the manufacturing process of the granule type sealed lead-acid battery.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a granular sealed lead battery.

[0002]

2. Description of the Related Art As a general liquid holding system for a sealed lead battery, there is a so-called retainer system in which a mat-like separator made of fine glass fibers is impregnated and held with an electrolytic solution. The battery of this type has a good initial capacity, but has a problem that the separator has a weak force to press the active material, and the life performance deteriorates early due to the deterioration of the active material and the expansion of the lattice.

[0003] In order to solve this drawback, in recent years, granular silica powder has been densely filled between the electrodes and around the electrode group, and the electrode plate, the separator and the granular silica have an electrolytic solution held therein. A sealed lead-acid battery has been proposed. Holding the electrolytic solution in the granular silica means to hold the electrolytic solution in the space between the granules or in the pores of the granules. The life performance is remarkably improved because the silica closely packed in the battery presses the electrode plate from all directions. For example, Japanese Unexamined Patent Publication No. 3-252063 describes a granular sealed lead battery in which a battery is filled with silica powder having a diameter of 10 to 500 μm, and an electrode plate, a separator, and an electrolyte are held in the silica powder. I have. Moreover, since silica powder is a very inexpensive material as compared with conventional glass fiber separators, it can be said that silica powder is an important material that enables provision of a battery that is inexpensive and has excellent performance.

[0004] As a method of manufacturing the above-mentioned granular sealed lead battery, a slurry filling method is known. This means that a predetermined amount of granules and an electrolytic solution are mixed in a slurry state, injected from the upper part of the battery, and then the inside of the battery is depressurized from the lower part and the excess electrolytic solution is discharged until a predetermined measured value is reached. It is a method.

[0005]

The above-mentioned silica powder used for the electrolyte holding material of the battery uses porous silica because it is necessary to hold as much electrolyte as possible. However, when the silica is made porous, the flowability of the silica deteriorates, and there is a disadvantage that it takes a considerable amount of time to fill the battery. Also, since such silica powder has a high specific surface area and the surface of the silica particles is not smooth, it takes a considerable amount of time to inject the electrolyte,
There was a disadvantage that the battery cost was high. Furthermore, since it is difficult for the electrolyte to enter, depending on the battery, only a smaller amount than the predetermined amount can be injected, and the discharge performance sometimes deteriorates.

FIG. 1 shows the amount of retentate per 1 g of granular silica (hereinafter referred to as “retentate ratio”) and the amount of discharge per unit time when the pressure inside the cell is reduced to discharge the surplus electrolyte (hereinafter, suction speed). The relationship is shown. At the start of discharging, the electrolyte is easily released because the retentate ratio of the granules is very high, but as the drainage proceeds and the retentate ratio decreases, only air escapes,
The electrolyte suction speed becomes very slow. In addition, since the suction speed immediately before the end is very large, the time required for sucking the excess electrolyte is not stable.

Accordingly, an object of the present invention is to provide a method of manufacturing a sealed granular lead-acid battery that reduces the time required for manufacturing.

[0008]

Means for Solving the Problems To solve the above problems, a method for producing a granular closed lead battery of the present invention comprises: a filling step of filling a slurry formed by dispersing granular silica in an electrolytic solution into a lead battery; Discharging a surplus electrolytic solution of the filled slurry, the method comprising the steps of: discharging a surplus electrolytic solution of the filled slurry; and supplying electricity to the granular closed lead battery in the charging direction during the filling step and / or the discharging step. Is carried out.

[0009] When the charging side is energized, the electrode plate which has been formed in advance is in an overcharged state, so that electrolysis of water immediately occurs on the surface of the electrode plate. Therefore, the electrolytic solution contained in the hole of the electrode plate is pushed out and discharged by the generated gas. As a result, for example, as shown in FIG. 2, since the electrolyte originally held on the electrode plate is held by the granules, the holding solution ratio of the granules temporarily increases, and is sufficiently sufficient in the region of a larger suction speed. The volume can be discharged.
When discharging the same amount as when no electricity is supplied,
The suction time can be shortened.

[0010] Preferably, the energization is performed with a charging current of 0.05 CA or more and 0.5 CA or less. This is because the effect on the battery can be suppressed and the discharge can be performed efficiently.

[0011]

Embodiments of the present invention will be described below with reference to the drawings.

The present invention relates to a method for producing a sealed granular lead-acid battery, in which granular silica is densely packed between the electrodes and around the group of electrodes, and the electrode plate, the separator and the granular silica retain an electrolyte. And the features of the
During the manufacturing process, current is supplied.

The granular silica is granular silica, that is, silica powder. Those having a diameter of 10 to 500 μm are preferred, and porous silica is particularly preferred. This is because a large amount of electrolyte can be held.

The electrolytic solution has a specific gravity of 1.25 to 1.34 (20
° C) dilute sulfuric acid.

The preparation of the slurry, which is a dispersion solution of the granular silica and the electrolytic solution, is not particularly limited, but preferably, in the step of dispersing the granular silica in dilute sulfuric acid,
It is preferred that the slurry filling tank is prepared by first adding diluted sulfuric acid, then adding granular silica and stirring, and finally injecting and stirring diluted sulfuric acid. This is because a solution in which the granular silica is uniformly mixed without adhering to the filling tank can be obtained. More preferably, the amount of dilute sulfuric acid injected last is preferably 20% or less of the total amount of dilute sulfuric acid injected.

The concentration of the above slurry is preferably in the range of granular silica / sulfuric acid = 0.15 to 0.25 g / cc. This is because the filling of the battery is completed quickly, and excess dilute sulfuric acid can be discharged quickly.

An electrode group including a positive electrode, a negative electrode, and a separator is housed in a battery case. As the positive and negative electrodes, use is made of an electrode plate which has been formed in advance. Then, the slurry is filled in the battery case.

During or after the step of filling the slurry, a step of discharging the surplus electrolytic solution of the slurry, that is, dilute sulfuric acid, is performed. Preferably, after filling, it is preferable to discharge after leaving to stand. The leaving time is preferably 2 seconds or more, and more preferably 30 seconds or less. By discharging the excess diluted sulfuric acid in the battery after the solution is uniformly filled, the granular silica can be uniformly and densely filled, and the electrolyte distribution in the battery after discharging the excess diluted sulfuric acid is also uniform. This is because good battery performance can be stably obtained.

During the filling step and / or the discharging step, power is supplied in the direction of charging the battery. Thereby, the time required for discharging can be shortened. Further, it is preferable that the energization is performed with a charging current of 0.05 CA or more and 0.5 CA or less. The charging voltage is
It is preferably 2.7 V or more. Particularly preferably, the charging current is 0.05 CA or more and 0.5 CA or less, and the charging voltage is 2.
It is preferable to conduct electricity at 7 V or more. This is because the time required for discharging the surplus electrolyte solution is significantly reduced without causing any adverse effect on the battery.

The discharge of the surplus electrolytic solution is performed by appropriately setting the discharge time and the discharge amount so that the characteristics of the battery are not impaired due to, for example, liquid withering.

[0021]

EXAMPLES Examples of the present invention will be described below together with comparative examples.

FIG. 3 shows an example of the structure of an apparatus used in the manufacturing method of the present invention. The granular sealed lead battery 2 is manufactured by storing an electrode group consisting of a pasted positive / negative electrode plate and a separator made of synthetic resin in a battery case (not shown), and then welding the lid. In the lower part of the battery case, a hole was provided in which a filter through which silica did not pass was attached, and a lid was provided with a slurry filling port. 1 is a slurry filling tank, 2 is a granular sealed lead battery, 3 is a vacuum pump, and 4 is a drainage tank.

A solution prepared by adding granular silica having an average particle diameter of about 60 μm (measured by a Coulter counter method) to a diluted sulfuric acid having a concentration of 0.20 g / cc and a specific gravity of 1.31 (20 ° C.) is filled from a charging port at the top of the battery. Then, while removing excess dilute sulfuric acid from the lower hole with a vacuum pump, the inside of the battery was filled with granular silica and the electrolyte was discharged. At the same time as dilute sulfuric acid is discharged,
Electric current was supplied from the DC power supply 5 to the battery in the charging direction. The time required for discharging the excess electrolyte at that time was measured.

The energization conditions are as follows: condition A: current 0.01 CA;
Maximum voltage 2.35V / cell, condition B: current 0.05C
A, maximum voltage 3V / cell, condition C: current 0.5CA, maximum voltage 3V / cell. For comparison, as a conventional condition, discharge was performed without energization, and the time required was measured.
Table 1 shows the results.

[0025]

[Table 1]

Under the conventional condition without energization, the discharge time up to a predetermined liquid amount takes 5 minutes, but by applying an electric current of 0.01 CA or more, the discharge time could be shortened. In particular, by applying a current of 0.05 CA or more, discharge could be performed in less than half the time.

[0027]

According to the manufacturing method of the present invention, surplus electrolyte can be discharged smoothly, and the time required for manufacturing can be reduced.

[Brief description of the drawings]

FIG. 1 is a diagram showing a relationship between a retention rate of an electrolyte and a suction speed of an excess electrolyte.

FIG. 2 is a diagram showing a distribution of an electrolytic solution before and after energization.

FIG. 3 is a diagram showing an example of a manufacturing apparatus according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Slurry filling tank 2 Granular closed lead battery 3 Vacuum pump 4 Drainage tank 5 DC power supply

Claims (2)

[Claims] 1. Production of a sealed granular lead-acid battery having a filling step of filling a slurry formed by dispersing granular silica in an electrolytic solution into a lead battery, and a discharging step of discharging excess electrolytic solution of the filled slurry. A method for producing a sealed granular lead-acid battery, comprising the step of energizing the sealed granular lead-acid battery in the charging direction during the filling step and / or the discharging step. 2. The method according to claim 1, wherein the energization is performed between 0.05 CA and 0.5 CA.
The method for producing a sealed granular lead-acid battery according to claim 1, wherein the method is performed with the following charging current.