JPH10308215A - Manufacture of sealed lead-acid battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrain the generation of non-formation part in an electrode plate by giving the same vibration with the natural frequency of a battery to the battery in a battery jar formation process. SOLUTION: Lead powder and dilute sulfuric acid are kneaded so as to form the paste, and after filling a positive electrode collector grid with this paste, aging and drying are performed so as to manufacture a non-formed positive electrode plate. This positive electrode plate is put in a battery jar, and dilute sulfuric acid is filled as the forming liquid and as the electrolyte so as to perform the formation. During this formation, an ultrasonic oscillator is provided in the jar, and ultrasonic oscillation at 20 kHz equal to the natural frequency of the battery is given. A battery, in which such an electrode plate is assembled, has a large initial capacity, and lowering of capacity with a cycle thereafter is restrained small, and charging and discharging characteristic is improved by transmitting the oscillation inside of the battery with a resonance effect, which is obtained by setting the ultrasonic oscillation to be given during the formation equal to the natural frequency of the battery, without generating attenuation, and promoting gas discharge, and restraining the local generation of non-formation part.

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 sealed lead-acid battery in which an electrode plate is formed in a battery case.

[0002]

2. Description of the Related Art The battery formation process of a lead-acid battery is as follows. An electrode group consisting of unformed positive and negative electrodes and a separator is placed in a battery case, a battery is assembled, and dilute sulfuric acid is injected as an electrolytic solution into the battery case. This is a step of oxidizing the positive electrode plate by applying electricity later and reducing the negative electrode plate to sponge-like metal lead by oxidizing the positive electrode plate. During the formation of the battery case, gas is generated from the electrode plate due to the electrolysis of water. When the gas generated from the electrode plate stays on the surface of the electrode plate, the contact between the active material and the electrolytic solution is hindered at that portion, the formation reaction does not sufficiently occur, and a local unformed portion is formed on the electrode plate. Problem. The above problem is particularly noticeable in a sealed lead-acid battery having a structure in which an electrolyte is substantially made non-fluidized by a retainer or the like. Therefore,
A study has been conducted on a technique to promote the desorption of gas generated from the electrode plate during battery case formation from the surface of the electrode plate (hereinafter abbreviated as gas escape) to suppress the formation of local unformed parts on the electrode plate. It has been. For example, JP-A-59-94367 discloses a technique for applying ultrasonic vibration to a battery case during formation of the battery case. By applying ultrasonic vibration during the formation of the battery case, outgassing is promoted, and the contact area between the active material and the electrolyte is ensured. As a result, formation of a local unformed portion on the electrode plate can be suppressed.

[0003]

However, in particular, in a sealed lead-acid battery in which the electrolyte is non-fluidized, if the frequency is not the natural frequency of the battery even when ultrasonic vibration is applied to the battery case during formation of the battery case. , The amplitude decreases due to interference. As a result, there is a problem that unformed portions are left locally on the electrode plate because gas is not sufficiently released. The problem to be solved by the present invention is to suppress the unformed portion from remaining on the electrode plate in the production of a sealed lead-acid battery in which the electrode plate is formed in a battery case.

[0004]

In order to solve the above-mentioned problems, a method for producing a sealed lead-acid battery according to the present invention, in which an electrode plate is formed in a battery case, comprises the steps of: Ultrasonic vibration of the same frequency is applied to the battery. By setting the ultrasonic vibration applied at the time of battery case formation to the natural frequency of the battery, it is possible to transmit large vibration into the battery due to the resonance effect. As a result, outgassing is sufficiently promoted, and formation of a local unformed portion on the electrode plate can be suppressed.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION A paste is prepared by kneading lead powder and dilute sulfuric acid for a certain period of time, filled in a positive electrode current collecting grid, then aged and dried to produce an unformed positive electrode plate. The non-formed negative electrode plate is manufactured under the same conditions as the non-formed positive electrode plate except that an organic additive is added. An electrode group, in which one unformed positive electrode plate is sandwiched between two unformed negative electrode plates via a separator (retainer) made of fine glass fibers, is inserted into a battery case to form a chemical solution and an electrolyte. Of diluted sulfuric acid into a battery case. The injected chemical and electrolytic solution is made non-fluidized by being held in a retainer. The natural frequency of the battery in this state was 20 kHz. The unformed battery composed of this unformed electrode plate is a single cell and has a standard capacity of 24 Ah. The above-mentioned battery case is put in a water tank, and a battery case formation is performed. In the chemical conversion operation, charging at a constant current of 200% of the standard capacity (3.2 A × 15 h) is performed. During the battery case formation process, an ultrasonic oscillator is installed in the water tank, and ultrasonic vibration of 20 kHz is applied to the battery.

[0006]

EXAMPLE A sealed lead-acid battery (example) having undergone the steps described in the above embodiment of the present invention and a sealed lead-acid battery manufactured under the same conditions as in the example except that the battery was not subjected to ultrasonic vibration during battery formation. Type lead storage battery (conventional example 1) and 25
A comparative study was conducted with a sealed lead-acid battery (Conventional Example 2) manufactured under the same conditions as in the example except that ultrasonic vibration of kHz was applied. The examination item is a charge / discharge cycle life test.
The test conditions were as follows: 6 sealed lead-acid batteries that had undergone the battery case formation process.
A for 2 hours, and after a 0.5 hour pause, a limiting voltage of 2.45
The charge and discharge cycle of charging for 6 hours at a constant voltage of 7.2 V and a maximum current of 7.2 A and resting for 3.5 hours is repeatedly performed. The capacity was confirmed by discharging the battery to a final voltage of 1.7 V at 6 A every 25 cycles. FIG. 1 shows the results. As is clear from FIG. 1, among the sealed lead-acid batteries manufactured by the conventional method (conventional examples 1 and 2), the sealed lead-acid battery (conventional example 2) subjected to ultrasonic vibration of 25 kHz has better charge / discharge. Although the cycle characteristics are shown, in the sealed lead-acid batteries manufactured by the method of the present invention and having the natural frequency (20 kHz) of the ultrasonic vibration applied to the battery during battery formation (Example), the sealed type of the conventional examples 1 and 2 was sealed. The initial capacity showed a larger value than that of the lead-acid battery, and it was clarified that the decrease in the capacity with the subsequent cycles was small and the charge-discharge cycle characteristics were significantly improved.

This is presumably because in the method of the present invention, by setting the ultrasonic vibration to the natural frequency, the vibration is not attenuated due to the resonance effect and is transmitted into the sealed lead-acid battery, and the gas escape is the best. In the sealed lead-acid batteries of Conventional Examples 1 and 2 in which the gas is considered to have accumulated on the surface of the electrode plate during the formation of the battery case, an unformed portion remains locally in the electrode plate, and the unformed portion has a general life span. It is presumed that the charge / discharge reaction did not proceed smoothly over a period of time and / or an excessive charge / discharge reaction was imposed on a portion other than the unformed portion, so that the deterioration of the portion was accelerated. Therefore, as compared with the sealed lead-acid batteries of Conventional Examples 1 and 2, the sealed lead-acid battery of the embodiment exhibited better charge-discharge cycle characteristics as a result of improved formation efficiency.

[0008]

According to the present invention, in the production of a sealed lead-acid battery in which a battery case is formed, it is possible to suppress the unformed portion remaining locally in the electrode plate. In addition, a sealed lead-acid battery having excellent charge-discharge cycle characteristics was thereby obtained.

[Brief description of the drawings]

FIG. 1 is a diagram showing the relationship between the number of charge / discharge cycles and the discharge duration.

Claims (1)

[Claims] 1. A method for producing a sealed lead-acid battery in which electrode plates are formed in a battery case, wherein the battery is subjected to ultrasonic vibration having the same frequency as the natural frequency of the battery during the battery case forming step. Manufacturing method for sealed lead-acid batteries.