JPH0443570A - Manufacture of sealed lead storage battery - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for manufacturing a sealed lead-acid battery for use in portable equipment, and more particularly to an improvement in the charging method thereof.

Conventional technology lead-acid batteries have higher energy density and are more economical than other batteries. In particular, sealed lead-acid batteries are used in VTRs these days.
The demand for small electronic devices such as devices is increasing, and the performance is improving significantly. Many proposals have been made regarding sealed lead-acid batteries. A typical example is to set the amount of electrolyte to be equal to or less than the pore volume of the electrode plate group consisting of the positive electrode plate, negative electrode plate, and separator, so that there is no so-called free liquid, and at the end of charging, the positive electrode A method is adopted in which oxygen gas generated from the plate is absorbed by the negative electrode plate to suppress the decrease in the amount of electrolyte. Sealed lead-acid batteries are used in a wide variety of applications because they do not contain free electrolyte, so they do not leak when placed horizontally or upside down, and do not require water replenishment.

Problems to be Solved by the Invention Charging of such a sealed lead-acid battery requires a chemically formed positive electrode plate,
When using a negative electrode plate, perform initial charging after injecting electrolyte into the electrode plate group, or when using an unformed electrode plate,
A common method is to perform battery cell formation after injecting the electrolyte.

After this initial charging or formation of the container, a capacity test is performed in which the battery is discharged a certain amount and the discharge voltage is measured, and a supplementary charge is performed in which the battery is charged by the amount of discharge for the capacity test, before being shipped as a product.

However, sealed lead-acid batteries shipped in this condition have a large amount of unstable lead dioxide (mainly α-Pb02) in the positive electrode plate, and most of it decomposes during the initial stage of storage. Since it produces coarse lead sulfate crystals that are difficult to charge, the amount of self-discharge is large and the capacity decrease is large.

If these coarse lead sulfate crystals are recharged in the presence of sufficient electrolyte, they will become stable lead dioxide (β-Pb02), and even if left to stand again, the amount of self-discharge due to the decomposition of lead dioxide will decrease. However, in sealed lead-acid batteries that limit the amount of electrolyte, it is difficult to charge. Especially in the constant voltage charging method used for boat fishing, the negative electrode plate has less self-discharge than the positive electrode plate. Since the charging current is limited depending on the charging state of the battery, the positive electrode plate becomes insufficiently charged, and unless the battery is charged for a long time or overcharged with a constant current, the battery capacity will not recover after long-term discharge. There was a point.

The present invention solves the above-mentioned problems, and aims to provide a method for manufacturing a sealed lead-acid battery that reduces the amount of self-discharge during storage and improves capacity recovery.

Means for Solving the Problems In order to solve the above problems, the method for manufacturing a sealed lead-acid battery of the present invention provides a method for manufacturing a sealed lead-acid battery at 50° C. after initial charging or after completion of battery cell formation.
After being left in an atmosphere of ~80°C for 10 days or less, supplementary charging is performed at room temperature.

Effect With this configuration, in the method for manufacturing a sealed lead acid battery of the present invention, the temperature of the sealed lead acid battery at 50° C. after initial charging or completion of battery cell formation.
By leaving the battery at ~80°C, unstable lead dioxide in the positive electrode plate is rapidly decomposed and then supplementary charged to convert it into stable lead dioxide.

EXAMPLE Hereinafter, a method for manufacturing a sealed lead-acid battery according to an example of the present invention will be described with reference to the drawings.

In the sealed lead-acid battery used in the test, both the positive and negative electrode plates were chemically formed in the plate state, and then the electrode plate group consisting of one positive electrode plate, one negative electrode plate, and a separator made of glass fiber was placed in a battery case and sealed. After that, by injecting dilute sulfuric acid as an electrolytic solution and charging it for the first time, the voltage reaches 6 V. 2. I created one with OA h.

In the case of this battery, a frame made of polyethylene (PE) surrounds the electrode plate group, both sides of the electrode plate group are held down by current collector plates made of a PE film and a tin plate laminated, and the frame body and the tin plate are held together. Using the PE film surface welded and sealed,
Compared to conventional ABS resin battery cases, it has a structure that is less likely to deform even when used at high temperatures.

Next, the initially charged battery was left at 25°C for a long time, and the battery was left at 40°C, 50°C, 60°C, 70°C or 80°C for 2 to 10 days, then taken out and charged at 0.2A. The batteries were classified into batteries that were supplemented for 5 hours, brought to a fully charged state, and left at 25°C for a long period of time. Batteries that have been charged for a long time at 25℃ will last for 2 weeks or more.
Residual capacity at 0.2A discharge every month and 7.35
The recovery capacity after 6 hours of V constant voltage charging was measured for 6 months, and the
Changes in capacity characteristics were compared when left at a high temperature of 0°C.

In addition, the high temperature storage period is determined by measuring the open circuit voltage during storage and determining the time period during which the open circuit voltage decreases to a constant level, that is, the time required for decomposition α.
-Until Pb02 runs out, set for each temperature,
In order to sufficiently compensate for the self-discharge amount at this time, 5
Recharging time is being carried out.

Figure 1 shows battery A that was left at 25°C for a long period of time without being exposed to high temperatures, battery B that was left at 40°C for 10 days, battery C that was left at 50°C for 6 days, and battery D that was left at 60°C for 4 days.
The remaining capacities of Battery E1 left at 170°C for 3 days and Battery F left at 80°C for 2 days after supplementary charging and left at 25°C for a long period of time are shown.

FIG. 2 shows the recovery capacity characteristics after measuring the remaining capacity shown in FIG. 1 and performing recovery charging.

Battery A, which was left for a long period of time without being left at high temperatures, showed a large decrease in capacity at the initial stage of storage, large variations in capacity during long-term storage, and a large decrease in recovery capacity. Even after charging, coarse lead sulfate crystals remained on the surface of the positive electrode plate of this battery.

However, batteries B-F that were left at a high temperature and then supplementally charged and left at 25℃ for a long period of time had less capacity loss and variation during storage, and less loss of recovery capacity, but batteries with a high temperature storage temperature of 40℃ In B, the effect is small, and the capacity variation and the recovery capacity are large when left for a long time, so the high temperature for high-temperature storage is preferably 50° C. or higher. As described above, the higher the high-temperature storage temperature, the less the capacity decrease during long-term storage, the better the capacity recovery, and the sufficient effect can be obtained in a short high-temperature discharge period.

However, in a battery case using ABS resin, the temperature is 60°C to 70°C.
is the limit for deformation of the battery case, and in battery cases made of composite PE resin and metal materials, it is possible to heat up to 80℃ to 90℃, but if the temperature exceeds 80℃, self-discharge of the negative electrode plate will occur rapidly. The practical limit for leaving it at high temperatures is 70℃ to 80℃.
It is.

Although this test only describes batteries using chemically formed plates, similar effects can be obtained with batteries formed using chemically formed containers, and cycle life characteristics have also been confirmed.

In addition, if a remaining capacity test is performed after leaving the device at a high temperature, it is possible to detect abnormalities such as a decrease in capacity due to poor airtightness or internal short circuits.

Effects of the Invention As is clear from the explanation of the embodiments above, the battery manufactured by the method for manufacturing a sealed lead-acid battery of the present invention shows little capacity loss and variation even when left for a long period of time, and has good capacity recovery. Are better.

The following may be the reason for this.

Lead dioxide, the positive electrode active material produced after initial charging or battery cell formation, contains a lot of α-PbO2, which is unstable and does not easily decompose. When this α-Pb02 gradually decomposes at room temperature, coarse lead sulfate crystals are formed, and charging However, since it is difficult to return to the active PbO2 state, a decrease in capacity and a decrease in recovery capacity occur after long-term storage. Therefore, before leaving it for a long time, it is necessary to leave it at a high temperature to avoid unstable α-
By decomposing Pb02 in a short time and converting it into fine lead sulfate that is easy to charge, and converting it to stable α-PbO2, the amount of self-discharge during long-term storage is reduced, and coarse lead sulfate that is difficult to charge is reduced. It is thought that the recovery capacity will also be improved since no is generated.

As mentioned above, the battery manufactured by the method for manufacturing a sealed lead-acid battery of the present invention has high reliability in capacity recovery even if left for a long period of time by being left at high temperature for a short period of time after charging. The value is extremely large.

[Brief Description of the Drawings] Figure 1 shows a battery manufactured by a method for manufacturing a sealed lead-acid battery according to an embodiment of the present invention after being left at various temperatures within the temperature range of 40°C to 80°C and then being refilled. A graph showing a comparison of the remaining capacity rate of the battery after long-term storage and after long-term storage at 25°C without high temperature storage. Figure 2 shows the recovered capacity rate when recovery charging is performed after measuring the remaining capacity in Figure 1. This is the graph voice that shows. Name of agent: Patent attorney Shigetaka Awano and 1 other person 4@1
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Claims (2)

[Claims] (1) A sealed lead-acid battery in which the positive electrode plate, negative electrode plate, and separator hold electrolyte, and the amount of electrolyte is limited to such an extent that there is no free liquid, and after initial charging or completion of battery cell formation,
A method for manufacturing a sealed lead-acid battery, in which the battery is left in an atmosphere of 0°C to 80°C and then supplementally charged at room temperature. (2) The period of leaving in an atmosphere of 50℃ to 80℃ is 10
2. The method for manufacturing a sealed lead acid battery according to claim 1, wherein the battery life is less than 1 day.