JPS6264058A - Manufacture of sealed lead-acid battery - Google Patents

Abstract

PURPOSE:To reduce the scattering of the amount of electrolyte and the concentration of electrolyte after completion of formation by pouring electrolyte into a plurality of cells each of which is formed by covering a plate group with an outer jacket, and connecting in series each cell with its thickness constant, then charging the sells for formation. CONSTITUTION:A plate group comprising a positive plate welded to a post, a negative plate, and a separator is covered with an outer jacket made of thermoplastic film or sheet to form a cell, then a plurality of cells are formed. After pouring electrolyte into each cell, the posts are connected in series with the thickness of each cell constant, and the cells are charged for formation. This formation makes the shrinkage ratio of separator in each cell constant, and this makes the amount of electrolyte contained in the separator constant. Therefore, the scattering of the amount of electrolyte and the concentration of electrolyte is reduce and the electrochemical performance of a battery is stabilized.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for manufacturing a sealed lead-acid battery used as a power source for portable equipment.

Conventional technology Sealed lead-acid batteries have a separator, such as a glass mat, that holds the electrolyte and prevents it from flowing, so the electrolyte does not leak out during charging, and has become widely used as a convenient and portable power source. ing.

In conventional sealed lead-acid batteries, a group of electrode plates consisting of a positive electrode plate, a negative electrode plate, and a separator is inserted into a box-shaped cell made of ABS resin, etc., and the valve is opened at a predetermined pressure to prevent high pressure inside the battery. It has a sealed structure with a lid that is glued or welded and equipped with a safety valve. In such a structure, since the separator has elasticity, a predetermined pressure is applied so that a sufficient volume can be extracted.

However, because of this structure, there are many steps in the manufacturing process that are difficult to mechanize, such as inserting the electrode plate group, gluing the lid, etc., and fitting the safety valve, which makes mass production difficult and leads to increased manufacturing costs. was.

As a countermeasure for this, as shown in Japanese Patent Application Laid-Open No. 58-83108, a film or sheet-like synthetic resin such as polyethylene is used as the electrolytic material to wrap the electrode plate group and seal it by heat welding. In addition, a method has been proposed in which a safety valve is also formed at the same time.

3. Problems to be Solved by the Heno Invention The method for manufacturing the above-mentioned battery, especially the method for chemically forming the electrode plates, involves forming an electrode group consisting of an unformed positive electrode plate and a negative electrode plate in the form of a film or sheet of polyethylene or the like. After encasing it in a synthetic resin body and injecting an electrolyte into the electrode plate, the pole columns were connected in series with each cell having a constant thickness, and chemical charging was performed. However, the chemical charging method had the following problems. That is, since there are variations in the thickness of the positive electrode plate, negative electrode plate, and separator in the cell, if the cell is formed with a constant cell thickness, the shrinkage rate of the separator is also changed with variation. In chemical charging,
Moisture in the electrolyte that is not contained in the separator and electrode plates is electrolyzed or evaporated. Therefore, when the shrinkage rate of the separator is high, the amount of water contained in the separator is small, and the amount of water reduced is large at the end of chemical charging. On the other hand, if the shrinkage rate of the separator is low, the amount of moisture loss will be small. Since the amount of electrolyte injected into the electrode group before chemical charging is regulated, the amount of electrolyte and the concentration of electrolyte at the end of chemical charging will vary greatly depending on the amount of water loss during chemical charging. Become. This variation greatly affects the characteristics of the battery itself, especially the storage characteristics and cycle life characteristics. Such problems occur when chemical charging is performed with each cell having a constant thickness.

The present invention is aimed at performing chemical charging to solve these problems.

Means for Solving the Problems In order to solve the above-mentioned conventional problems, the present invention has provided an electrode group consisting of a positive electrode plate, a negative electrode plate, and a separator, each welded to a pole pole, using a thermoplastic film. Alternatively, prepare multiple cells surrounded by an outer covering made of sheets, inject electrolyte into each cell, connect the poles in series with each cell with a constant thickness, and perform chemical charging. The present invention provides a method for manufacturing a sealed lead-acid battery characterized by the following.

Function: In this chemical charging method, the shrinkage rate of the cellopagerator during chemical charging is constant for each cell. Therefore, the amount of electrolyte contained in the separator is constant for each cell, and the amount of water loss during chemical charging varies only due to variations in the amount of electrolyte contained in the electrode plates.

Generally, in a sealed lead-acid battery, 60% or more of the total amount of electrolyte contained in the electrode plate group is contained in the separator. The variation in the amount of water loss during chemical charging is less than half that of the conventional chemical charging method. That is, in the chemical charging method of the present invention, by making the variation in the amount of water loss during chemical charging smaller than in the conventional method, the variation in the amount of electrolyte and the electrolyte concentration at the end of chemical charging is reduced, and the battery The electrochemical properties of can also be stabilized.

Example The present invention will be explained in detail below.

6 Prepare 10 cells by storing the electrode plates to be assembled in a polyethylene film, inject a certain amount (8 ml) of electrolyte into each cell, and connect the 10 cell poles in series. Charged chemically. In the chemical charging method of the present invention, the bag was fixed to a pressure jig so that a pressure of 20 Kq/am'' was always applied to the electrode plate group of each cell during chemical charging.For comparison, the conventional Chemical charging was also carried out by the method of
The bag was fixed to a jig so that a pressure of 5 Kq/dm was applied to the electrode plate group at the start of chemical formation, the cell thickness was kept constant, and chemical charging was performed. Conventional chemical charging method (i=) B method.To method,
Yotte to B method, each 6 o Seno v, 2 V, 1. An oAh battery was created.

FIG. 1A shows the distribution of the amount of water loss during chemical charging in Method A and Method B. Comparing the two methods, it can be seen that the average value of the amount of water loss is almost the same, but the variation is much smaller in the method. -! However, it is clear that the variation in the electrolyte concentration and amount of electrolyte in each cell is smaller in the cells charged by the 7-cycle method.

Next, the results of examining the storage characteristics of cells charged by method B and method B are shown in Figure 2, Figure 2, A9. To evaluate storage characteristics, after checking the initial capacity at a 5-hour rate, each cell was incubated at 60°C.
A method was employed in which the battery was left in an atmosphere for 2 weeks, and the subsequent 6-hour rate capacity was checked, and this was determined as the total capacity remaining rate relative to the initial capacity, and the magnitude of self-discharge was determined. From the results in Figure 2,
It is clear that the variation in the remaining capacity rate of cells charged by method B is much smaller than that of cells charged by method B.

Effects of the Invention As described above, the electrochemical characteristics of the battery manufactured by the chemical charging method of the present invention have very small variations, stable quality, and reliability compared to batteries manufactured by the conventional method. It's expensive. As described above, the present invention provides a manufacturing method of great industrial value.

Figure 1 (a) 9 is a characteristic diagram showing the decrease in water content during chemical conversion charging according to the present invention and the conventional method, and Figure 2 (a) is a characteristic diagram showing the decrease in water content during chemical charging of the present invention and the conventional method.

The figure above is a diagram showing the storage characteristics of the same battery.

Name of agent: Patent attorney Toshio Nakao (1st person)
Figure Iha Direction Figure 2 I/) Pig 5 and B1 Power Bga

Claims (1)

[Claims] (1) Prepare a plurality of cells in which a group of electrode plates, each consisting of a positive electrode plate, a negative electrode plate, and a separator, each welded to a pole pole, is surrounded by an outer cover made of a thermoplastic synthetic resin film or sheet, and each cell After injecting an electrolyte into the cell, the pole columns are connected in series while applying a constant pressure in the thickness direction of each cell, and chemical charging is performed while the applied pressure does not change over time. Manufacturing method for lead-acid batteries.