JP3047640B2 - Manufacturing method of sealed lead-acid battery - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a sealed lead-acid battery, and more particularly to a method for manufacturing a sealed lead-acid battery having no internal short circuit.

[0002]

2. Description of the Related Art Due to the structure of an electrochemical cell, the positive electrode and the negative electrode must be in an electrically conductive and insulated state inside the cell. However, conventionally, in the manufacturing process of the lead storage battery, the positive electrode plate and the negative electrode plate may be short-circuited inside the battery due to a surplus active material or a protrusion on the electrode plate, or a displacement of the electrode plate during assembly. Such an internal short circuit in the battery may cause a capacity reduction due to discharge inside the battery, or an explosion may occur due to the oxyhydrogen gas generated inside the battery during charging as a short-circuited portion serving as an ignition source.

[0003] For this reason, an internal short circuit is usually inspected after the construction of the electrode group. One is visual inspection. However, since the inspection can be performed only at a visible position, a short circuit inside the electrode group cannot be found. The other is an electrical test in which a high voltage is applied between the positive and negative electrodes. Since the positive electrode and the negative electrode of a normal battery before liquid injection are insulated via the separator, no current flows even when a high DC voltage is externally applied between the positive and negative electrodes. However, if there is an internal short circuit, it is judged from the current flowing, and an inspection for the presence or absence of a short circuit is performed.

[0004]

However, such a conventional short-circuit inspection method has the following problems in the case of a sealed lead-acid battery using a separator containing glass fiber as a main component.

[0005] That is, when the separator is left in the air,
Moisture adsorbs on the glass fibers due to the humidity in the air.
When a high voltage for short-circuit inspection is applied between the positive and negative electrodes of a non-injected battery prepared using such a water-containing separator, water in the separator is electrolyzed. Therefore, a current corresponding to electrolysis flows even in a normal non-short-circuited battery, and it may not be possible to determine the presence or absence of a short-circuit.

[0006] It is very difficult to assemble a battery so that the separator is not affected by humidity.

An object of the present invention is to solve such a problem, and an object of the present invention is to provide a method for reliably detecting a micro-internal short-circuited battery and manufacturing a sealed lead-acid battery having no internal short-circuit.

[0008]

The method for manufacturing a sealed lead-acid battery according to the present invention is obtained by interposing a separator mainly composed of glass fiber having adsorbed water between a positive electrode plate and a negative electrode plate, both of which have been formed. It is characterized in that a sealed lead-acid battery having no internal short circuit is manufactured by inserting the electrode group into a battery case, measuring the battery voltage before injecting the electrolytic solution, and detecting an internal short circuit.

In order to more surely detect an internal short circuit, the inside of the battery is decompressed before the measurement of the battery voltage, or the final electrolyte volume of the unfilled battery is 0.1 to 0.2. weight%
Or it is preferable to measure the battery voltage with a voltmeter having an internal impedance of 10 ¹³ Ω or more.

[0010]

The separator composed mainly of glass fibers containing adsorbed water is in the same state as holding a very small amount of electrolyte. When a non-injected electrode plate group is formed using the positive and negative electrode plates that have been formed together with this separator and inserted into the battery case, the separator is compressed together with the electrode plate and is completely adhered, so that a very small amount of discharge capacity is obtained. Battery can be constructed, and a voltage is generated between the positive and negative electrodes.

In a normal state in which the internal battery is not short-circuited, the battery voltage always shows a constant value. However, when the internal short circuit occurs, the battery is discharged inside the battery, so that the battery voltage is lower than that of a normal battery. Since the discharge capacity of the non-injected battery is very small, the battery voltage is reduced even in a minute short circuit. Therefore, by measuring the battery voltage of a battery that has not been injected, a battery that is internally short-circuited can be found.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment according to the present invention will be described below in comparison with a conventional technique.

[0013] Both the positive and negative electrode plates which have already been formed and a separator mainly composed of glass fibers in which adsorbed water is present are used at 2 V,
A 200 Ah non-injected battery was prepared. Using this unfilled battery, a resistor was changed in resistance value as a pseudo short circuit and connected between the positive and negative electrodes. In order to adsorb moisture on the glass fiber, the separator was previously left in a humidity atmosphere of 20% or more for 2 hours or more.

Table 1 shows test results comparing a method of measuring a current flowing by applying a high voltage between the positive electrode and the negative electrode according to the prior art with a method of measuring a battery voltage according to the present invention.

[0015]

[Table 1]

According to the prior art, even in a normal battery without resistance connection, about 1 at an applied voltage of 250 V is used.
A current of 50 mA flows. This is because the adsorbed water or moisture in the glass fiber separator becomes an electrolytic solution between the electrode plates, and a current for electrolysis flows. In a non-injected battery connected with a pseudo short-circuit resistance of 1 kΩ or less, a clear difference occurs in the current flowing from a battery with no resistance connected (normal battery), and a short circuit can be determined. It is difficult to determine a short circuit because there is no clear difference between the two.

In the method according to the present invention, a battery voltage of about 1.5 V is applied to a battery (normal battery) to which no pseudo short-circuit resistor is connected.
Occurred. This is because the adsorbed water in the glass fiber separator became an electrolyte between the electrode plates to form a battery having a very small discharge capacity, and a battery voltage was generated between the positive and negative electrodes. When a pseudo short-circuit resistor is connected to this battery, the battery with a small capacity is discharged due to the short circuit, and the battery voltage is reduced. Therefore, a clear difference occurs between the normal battery and the battery voltage, and the short-circuit battery can be determined. Further, in the method according to the present invention, the magnitude of the short-circuit resistance could be determined up to 1 MΩ. The voltmeter used for the measurement had an internal impedance of 10 ⁹ Ω.

Although the time from the connection of the pseudo short-circuit resistor to the measurement of the voltage after connection is set to one hour, if the time until the measurement is further increased, the discharge by the resistor is prolonged, and the battery voltage is greatly reduced. Even a large pseudo-short-circuit resistance can be determined, which is superior to the conventional method.

Since this method measures the battery voltage of a non-injected battery, a battery using an unformed electrode plate cannot be used because no battery voltage is generated. In a liquid battery or the like that does not use a separator containing glass fiber as a main component, a battery voltage does not occur because the adhesion between the electrode plate and the separator is small.
Therefore, it is necessary to combine a chemically-formed electrode plate and a separator mainly composed of glass fiber.

Further, since the battery case of the sealed lead-acid battery is made of a resin material such as ABS or PP, when the inside of the battery is decompressed, the battery case goes down toward the inside of the battery. Since the separator mainly composed of glass fiber has elasticity, the electrode plate group is compressed in the electrode plate thickness direction. In the case of an actual short-circuited battery, when the short-circuit between the positive and negative electrodes or the short-circuited electrode group is in a state of being short-circuited, the contact state of the short-circuit portion is ensured by being compressed, the resistance value of the short-circuit is reduced, Since the discharge current due to the short circuit increases and the battery voltage decreases, the short circuit can be more easily detected.

In this embodiment, the test was performed with a 200 Ah battery. However, as can be seen from the measurement principle, the test can be performed regardless of the size of the capacity. However, especially in the case of batteries with a small discharge capacity, the very small discharge capacity of the unfilled battery becomes even smaller and battery voltage is generated, but when a voltmeter is connected to the battery, the very small amount of measured current flowing in the voltmeter is measured. As a result, the battery is discharged and the battery voltage drops. For this reason, it is difficult to determine the short circuit. In such a case, in order to further improve the inspection accuracy, the following method was found to be excellent.

That is, by injecting an electrolyte of 0.1 to 0.2% by weight of the final injected electrolyte into an uninjected battery in advance, the separator holds a small amount of the electrolyte, and is measured by a voltmeter. The current does not lower the battery voltage. The reason for setting the injection amount to be 0.1 to 0.2% by weight of the final injected electrolyte amount is that when the electrolyte amount of less than 0.1% by weight is insufficient, the amount of the electrolyte solution is not sufficient and the voltmeter is used. The battery voltage drops due to the measured current, and
This is because, when an electrolyte exceeding 0.2% by weight is injected, the discharge capacity of the battery increases, and the discharge voltage of the short-circuited battery is large, so that it takes time to lower the battery voltage, which is not preferable.

A normal voltmeter has an internal impedance of about 10 ⁹ Ω, and a measured current of the battery voltage flows with respect to the internal resistance. Therefore, if the measured current can be reduced, the battery voltage can be prevented from lowering. Therefore, if a voltmeter having an internal impedance of 10 ¹³ Ω or more is used, the battery voltage of the extremely dry separator battery can be measured normally.

[0024]

As described above, according to the method for manufacturing a sealed lead-acid battery of the present invention, a conventional voltmeter can be used to find a conventional voltmeter without using an expensive device for generating a high voltage. It is also possible to easily find a micro short circuit, which has been difficult, and to manufacture a highly reliable sealed lead-acid battery.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-4-138674 (JP, A) JP-A-61-176773 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01M 10/42-10/48 H01M 10/06 H01M 10/12

Claims (4)

(57) [Claims] 1. An electrode plate group obtained by interposing a separator mainly composed of glass fiber having adsorbed water between a positive electrode plate and a negative electrode plate, both of which have already been formed, is inserted into a battery case, and an electrolyte is injected. method for producing a sealed lead acid battery, characterized in Teisu Rukoto measuring the battery voltage before. 2. The method for manufacturing a sealed lead-acid battery according to claim 1, wherein the pressure inside the battery is reduced before the battery voltage is measured. 3. The method for manufacturing a sealed lead-acid battery according to claim 1, wherein an electrolyte amount of 0.1 to 0.2% by weight of the final injected electrolyte amount is injected before the measurement of the battery voltage. . 4. The method according to claim 1, wherein the battery voltage is measured by a voltmeter having an internal impedance of 10 ¹³ Ω or more.