JPH0479107B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an improvement in the manufacturing method of paste-type electrode plates for lead-acid batteries, and its purpose is to pass the electrode plate filled with paste between a pair of rotating rollers with different upper and lower rotational speeds. This improves the active material retention performance of the electrode plate and battery performance. In conventional electrode plates manufactured using a pair of rotating rollers that drive only the lower part, if the filling machine is single-sided coating, the grating is often exposed on one side of the electrode plate. In such an electrode plate, since the contact area between the grid and the active material is reduced, the grid cannot sufficiently perform its original role of holding the active material and functioning as a current collector. Therefore, batteries manufactured using such electrode plates have problems such as a short life due to shedding of the active material and a decrease in discharge capacity and charging efficiency due to a decrease in the reaction area between the lattice and the active material. The electrode plate manufactured by the manufacturing method according to the present invention has a completely covered grid and solves the above-mentioned problems. In addition, in the past, in order to deal with the above-mentioned problems, the amount of sulfuric acid used during paste preparation was reduced to soften the paste before filling, but as a result, the amount of active material filled increased. It will no longer be suitable for the production of lightweight batteries that are being promoted. The manufacturing method according to the present invention is very effective and applicable to manufacturing lightweight electrode plates. The present invention will be explained below using the drawings. Figure 1 is an example of a conventional manufacturing method, and shows a schematic cross section when an electrode plate filled with paste is passed between a pair of rotating rollers, where 1 is an active material, 2 is a lattice, 3, 3' indicates a rotating roller. Further, arrows inside the rotating rollers 3, 3' indicate the rotation direction of the rotating rollers 3, 3'. Of the pair of rotating rollers 3, 3', only the lower rotating roller 3' has a driving device, and the upper rotating roller 3 rotates naturally. In this case, the exposed portion of the grid 2 caused by being compressed perpendicularly to the electrode plate and filled with a single-sided filling machine remains as it is. FIG. 2 shows an embodiment of the manufacturing method according to the present invention.
This is a schematic cross-sectional view of the electrode plate filled with paste and passed between a pair of rotating rollers. In the figure, the same reference numerals as in FIG. 1 indicate the same operating members. Note that in the conventional case, only the lower rotating roller 3' has a drive device, and the upper rotating roller 3 has a driving device.
In contrast, in this embodiment of the present invention, rotation is also transmitted to the upper rotating roller 3 through gear connection, and furthermore, due to the difference in gear ratio, the rotational speed of the lower rotating roller 3' is higher than that of the upper rotating roller. It is designed to be slower than roller 3. Specifically, rollers with a diameter of 210 mmφ for both the upper and lower rollers were used, and the rotation speed of the upper roller was 42 r.pm/min, and the rotation speed of the lower roller was 38 r.pm/min. In this case, the difference in circumferential speed of the upper and lower rotating rollers is approximately 4.4
cm/sec. In the case of this embodiment of the present invention, as shown in FIG. 2, the swollen portion 4 of the active material 1 on the back side of the electrode plate (encircled by a broken line) caused by single-sided filling is the rotating roller 3. , 3', the lower rotating roller 3' has a slow rotation speed.
By being rubbed by the surface, the active material 1 is displaced, pushed backwards and compressed, and the area 5 surrounded by diagonal lines is
The exposed portion of the grating 2 is completely covered with the active material 1, and the electrode plate has a flat surface. In order to obtain an electrode plate that is well filled with active material to the back side of the electrode plate, has a uniform thickness, and has a tight paste, an appropriate roll press pressure (1.5~
2.0Kgf/cm ² ) and a slight slip between the lower roller and the electrode plate (approximately 1 to 5 kgf/cm 2 due to speed difference).
cm/sec). There is a limit to the range in which slipping can occur under pressure, and if it is too large, problems such as deformation of the electrode plates will occur, so the speed difference should be set within an appropriate range. Next, the electrode plate manufactured by the method according to the present invention is subjected to acceleration.
10 under the conditions of 5g, 2mm amplitude, and 2000 vibrations per minute.
Table 1 shows the results of examining the state of the active material falling off the electrode plate after being vibrated for a minute, in comparison with the case of a conventional product.

[Table] From the results, it was found that the product of the present invention had almost no shedding of the active material and had excellent vibration resistance. Next, a battery with a nominal capacity of 28 Ah was prepared using both positive and negative electrode plates manufactured by the method according to the present invention, and an initial capacity test and a life test based on JIS regulations were conducted. The test results are shown in Table 2 in comparison with conventional products.

[Table] From the results, it was found that the battery manufactured by the manufacturing method of the present invention was superior in both initial performance and life cycle. In the above embodiment, the difference in circumferential speed between the upper and lower rollers in contact with the electrode plate surface was set by changing the rotational speed of the rollers, but it is also possible to adjust both the rotational speed and the roller diameter by changing the roller diameter or at the same time. It can also be set by As described above, the electrode plate manufactured according to the present invention has almost no shedding of the active material and has excellent battery performance, so the method for manufacturing the electrode plate according to the present invention is extremely useful.

[Brief explanation of the drawing]

FIG. 1 is a schematic sectional view of an electrode plate passing between rotating rollers, showing an example of a conventional electrode plate manufacturing method, and FIG. 2 is a schematic cross-sectional view of an electrode plate passing between rotating rollers, showing an example of an electrode plate manufacturing method according to the present invention. FIG. 3 is a schematic cross-sectional view when passing between 1... Active material, 2... Grid, 3, 3'... Rotating roller.

Claims (1)

[Claims] 1. In a method for manufacturing a paste-type electrode plate for a lead-acid battery, in which an electrode plate filled with active material paste from one side of a grid is passed between a pair of rotating rollers, the electrode plate on the side opposite to the side filled with active material paste is A method for manufacturing a paste-type electrode plate for a lead-acid battery, characterized in that the circumferential speed of the rotating roller is set to be slower than the circumferential speed of the rotating roller on the electrode plate surface on the active material paste filling side. .