JPH0322857Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an improvement in a bag-like separator that wraps around an electrode plate in a lead-acid battery.

Until now, we have developed a cast grid electrode plate in which a cast grid is filled with a paste-like active material, and in particular, a bag-shaped separator that wraps the anode plate to isolate it from the cathode plate and prevent the depositing of fallen active material on the bottom of the battery case. Measures have been taken to extend the lifespan.

On the other hand, recently, electrode plates using expanded grids have been developed, which have far superior productivity and work continuity compared to cast grids. A predetermined portion of a strip-shaped lead alloy sheet is cut and expanded to form a polygonal, for example, diamond-shaped lattice grid (active substance holding cell).
When an expanded lattice is continuously formed and cut into a predetermined size, both left and right ends remain open. Therefore, unlike a cast lattice, there are no left and right frame ribs, so it is necessary to protect the lattice even more reliably by encasing it in a bag-like separator.

Until now, a microporous synthetic resin sheet has been used as a bag-like separator to protect the expanded grid electrode plate, and after folding this in half into a U-shape,
The left and right open ends were fixed by heat welding or ultrasonic welding. However, if the open end portions are completely heat welded into a band shape, the shape of the separator may be distorted due to melting and deformation of the resin, or the molten resin may drip from the end portions. Since it is necessary to prevent these problems, it has been common practice to use separators that are considerably larger in size than the electrode plates. Further, when the resin sheet is thick, the bonding strength becomes weak, and there is a problem in that management such as controlling the bonding temperature using a thermal welding method becomes complicated. On the other hand, in the case of ultrasonic welding, it is possible to control the heat generation in the seal part due to ultrasonic welding to the desired area, and the separator dimensions are not made larger than the electrode plates, but when welding, an ultrasonic welding machine is used. The drawback is that it is necessary and expensive.

The present invention is a bag-shaped separator made by folding such a microporous synthetic resin sheet into a U-shape.
Excluding the part where the electrode plate is inserted among the open parts in three directions 2
By fixing both ends of the open part in a band shape with alternating small concave and convex parts that are interlocked, it is possible to create an expanded lattice pole with both left and right ends open. Even if it is a board, it can be wrapped around it to ensure protection.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In FIG. 1, 1 is a bag-shaped separator according to an embodiment of the present invention. As mentioned above, this bag-like separator suitable for wrapping the expanded grid electrode plate is made of a thermoplastic resin sheet having microporosity and appropriate rigidity, such as the microporous polyethylene sheet 1a shown in FIG.
It is formed of. And one side of it, namely U
When folded in half in a letter shape, the filled active material is partially pressurized on the inner surface facing the electrode plate, and a small gap is secured between the separator and the electrode plate surface to promote the circulation and diffusion of the electrolyte. It is preferable to form short ribs extending in the longitudinal direction at predetermined intervals.

The separator shown in FIG. 2 is folded in half in a U-shape at the center in the longitudinal direction, and is placed on both left and right ends 2, 2' of the separator kept in the state shown in FIG.
This part is a pair of meshing gears 3 shown in FIG.
50 ~ while passing between the pressure jig 4 consisting of 3'
Under the pressure of 100Kg/ ^cm2 , a concave part and a convex part are formed with a width and depth according to the gear tooth dimensions.The concave part is located at the bottom of the upper convex part, and the convex part of the gear By passing a separator through the part and the recess so that they fit well, they are pressed together and physically fixed.

Note that fixation by forming this pressurized and crimped portion is achieved by the combination of the meshing effect and the pressurized bonding force, as fine concave portions and convex portions are alternately positioned and engaged with each other. That is, due to the meshing effects of the upper concave and lower convex portions of the pair of meshing gears A and the upper convex portion and lower concave portion of B, the superimposed microporous sheets are stretched greatly, with the upper sheet in A and the lower sheet being stretched significantly. , the reaction forces a strong force to push them back inward, forming a bonded shape.

Furthermore, it is thought that the pressure bonding force is strong in the portion corresponding to the gear tooth corner, and a portion of the surface is welded due to localized heat generation.

Therefore, unlike thermal welding, there is no need for a separator that is considerably larger in size than the electrode plates, and unlike ultrasonic welding, no expensive equipment is required; A bag-like separator can be formed easily and inexpensively by simply passing the bag-like separator through the pressurizing jigs. Moreover, the separator according to the present invention does not require any heat source for pressurizing and crimping, and the crimping and fixing strength at both left and right ends maintains 70 to 80% of the strength of fixing by ultrasonic welding. The interlocking portion of the bag-shaped separator had sufficient tensile strength to accommodate.

[Brief explanation of drawings]

FIG. 1 is a perspective view of a bag-shaped separator according to an embodiment of the present invention, FIG. 2 is a plan view of a microporous sheet constituting the separator, and FIG. 3 is a perspective view of the sheet folded in two into a U-shape. FIG. 4 is a side view showing a state in which both left and right ends of a sheet folded in half are pressed together with a pressing jig consisting of a pair of gears. DESCRIPTION OF SYMBOLS 1... Bag-shaped separator, 1a... Microporous sheet, 2, 2'... Left and right ends of the sheet, 5... Band-shaped crimped portion in which concave portions and convex portions are alternately located.

Claims (1)

[Scope of utility model registration request] A single microporous synthetic resin sheet is folded in two in a U-shape, and the left and right open ends are crimped into a band shape with fine concave and convex portions positioned alternately and interlocked. A bag-shaped separator for lead-acid batteries.