JPS5816836A - Manufacture of storage battery casing - Google Patents

Abstract

PURPOSE:To attain storage battery casings having enough rigidity for large type or superlarge type by a method wherein resin with electrolyte resistance performance is injected into a mold through first gates in communication with through holes of a core material and second gates other than those first ones. CONSTITUTION:Resin 12 residing in a runner 7 is injected from first and second gates 10, 11 through first and second spurs 8, 9. At this time, the resin 12 injected from the first gates 10 is quickly pushed into an inner cavity 19 via through holes 14 to fill the same. Meanwhile, the resin 12 injected from the second gates 11 is quickly pushed into an outer cavity 20 to fill the same. The resin spreads over the entire cavity between a male mold 4 and a female mold 5 including both inner and outer cavities 19, 20. After curing of the resin 12, the male mold 4 is removed from the female mold 5 and then the molding product is taken out to obtain a storage battery.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a storage battery case, and more particularly to an efficient method for manufacturing a storage battery case having a rigidity suitable for large to extra-large sizes.

Large to extra-large storage batteries are generally used for stationary use as backup or independent power sources.

In particular, what has been attracting attention recently is the charging of late-night electricity.
It is a storage battery that aims to improve the efficiency of power consumption, and such storage batteries are required to be large or extremely large.
Depending on the size, the container will be large or super dog-shaped.

On the other hand, recently, synthetic resins have been increasingly used as materials for storage battery containers. Polypropylene, in particular, has excellent electrolyte resistance such as chemical resistance and heat resistance. However, when a large or extra-large battery case as described above is made of a synthetic resin such as polypropylene, the material is not satisfied because its rigidity is relatively low. It was extremely difficult to obtain a strong battery case.Currently, 20
There are examples of battery cases constructed with a wall thickness of ~25111 mm, but as the wall thickness increases, curing time is extremely long, and there are also quality problems such as "sink marks" and bubbles, and molding problems. There are also many technical problems. Furthermore, as the molding machine becomes larger, the molded products handled also become larger, making it difficult to carry out efficient molding, and thus increasing product costs.

Therefore, the main object of the present invention is to provide a method for manufacturing a storage battery case that can advantageously overcome the above-mentioned problems.

Simply put, this invention involves placing a core material made of a rigid material in a mold in advance, injecting an electrolyte-resistant resin into the mold, and then covering the core material with the resin. In this manufacturing method, the core material has an annular sprue protrusion that protrudes at a predetermined height on one side of a portion corresponding to the bottom wall and has a through hole in the center. A part of the gate of the mold is formed in advance and aligned with the through hole of this sprue projection, so that the injected resin quickly spreads to both sides of the core material placed in the mold. It is characterized by the following.

Other objects and features of the present invention will become more apparent from the detailed description given below with reference to the drawings.

FIG. 1 is a perspective view showing an example of a large or extra-large battery case to which the present invention is advantageously applied.

The storage battery case 1 shown here has an overall shape including a bottom wall and a side wall 2 extending upward from the bottom wall. Note that the bottom wall is hidden by the side wall 2 and is therefore not shown in this drawing. A stepped portion 8 is formed on the side wall 2, and this stepped portion 8 is for receiving and suspending an electrode plate (not shown) disposed inside the battery case 1. This ), b storage battery case 1 can be manufactured according to the present invention as follows.

FIG. 2 is a schematic cross-sectional view showing the injection process of an embodiment of the present invention. FIG. 3 is a plan view of the storage battery case obtained by the injection process shown in FIG. 2.

Referring to FIG. 2, in carrying out an embodiment of the present invention, a male mold 4 and a female mold 5 as molding molds, and a core material 6 having an overall shape that roughly follows the shape of a storage battery container are used. It will be prepared.

The male mold 4 and the female mold 5 define a cavity corresponding to the outer shape of the storage battery case 1 shown in FIG. A runner 7 is formed in one of the molds, for example, the female mold 5, and from this runner 7 the first and second sprues 8, 9.
The resin 12 is injected into the first and second goo (10.11) through the process.

One side of the bottom wall equivalent portion 18 of the core material 6, for example, the lower surface side (
An annular sprue protrusion 15 that protrudes at a predetermined height and has a through hole 14 at its center is provided at the top (in FIG. 2). The through hole 14 of this sprue projection 15 is selected so as to correspond in position to the first game 10 described above. A side wall equivalent portion 16 of the core member 6 is formed with a lateral protrusion 17 that projects at a predetermined height. A height direction projection 18 is formed on the upper end surface (lower side in FIG. 2) of this side wall equivalent portion 16. As is clear from Fig. 3, the lateral protrusion 1
7 are provided on each surface of the side wall equivalent portion 16, and one height direction protrusion 18 is provided on each hexagonal portion of the side wall equivalent portion 16.

Such a core material 6 is placed in a cavity defined by a male mold 4 and a female mold 5, as shown in FIG. At this time, the first gate IO is connected to the through hole 14 of the sprue protrusion 15.
becomes connected. Further, the core material 6 includes a sprue protrusion 15,
It is positioned relative to the male mold 4 and female mold 5 by the lateral projections 17 and the height projections 18 . As a result, an inner cavity 19 and an outer cavity 20 are formed on both sides of the core material 6, respectively.

The resin 12 in the runner 7 is connected to the first and second sprues 8, 9.
through the first and second goose) 10, 11. At this time, the resin 12 injected from the first gate lO
is quickly pushed into the inner cavity 19 through the through hole 14 and fills it. Further, the resin 12 injected from the second goo 11 is quickly pushed into the outer cavity 20 and fills it. In this way, the core material 6
By simultaneously injecting the resin from the inside and outside of the core material 6, the pressure applied to the inside and outside of the core material 6 is approximately the same, and a portion of the core material 6 is pressed against the male mold 4 or the female mold 5 to form a molded product. The core material 6 is not exposed on the inner or outer surface of the core material.

As a result of the molding process, the tree [12] spans all cavities between the male mold 4 and the female mold 5, including the inner cavity 19 and the outer cavity 20. After waiting for the resin 12 to harden, the male mold 4 and the female mold 5 are separated and the molded product is taken out, thereby obtaining a storage battery case 1 as shown in FIGS. 1 and 8.

In this storage battery case 1, the resin 1B is in a state in which the core material 6 is covered.

The core material 6 described above is made of a rigid material. For example, it is constructed from a composite material of polypropylene containing mica or polypropylene containing mica and glass fibers. For polypropylene containing mica, 1.
For example, about 80% mica is contained. In volippyrene containing mica and glass fibers, mica gos
and about 16% glass fiber. The core material 6 made of a composite material can be easily formed by molding. As the resin 12 formed to cover the core material 6, an electrolyte-resistant resin is used. A typical example thereof is polypropylene, and when such polypropylene is used as the electrolyte-resistant resin 12, it has extremely good compatibility with the core material 6, which also contains polypropylene. Note that any other arbitrary materials can be used for these elements as long as the core material 6 is a rigid material and the resin 12 is an electrolyte-resistant material.

In addition, in the above-mentioned embodiment, the lateral protrusion 17 and the height protrusion 18 provided as a means for positioning the core material 6 with respect to the male die 4 and separation 5 are not limited to these shapes and positions. , other variations are also possible. For example, a portion corresponding to the lateral protrusion 17 may be formed inside the side wall portion 16 of the core member 6 . Further, although the sprue protrusion 15 is provided so as to protrude outward from the bottom wall corresponding portion 18, it may be located inside by changing the path of the resin 12. However, as shown in the drawing, if the sprue protrusion 15 and the lateral protrusion 17 are provided so as to protrude to the outside of the core material 6, the inner surface of the battery case l is completely covered with the electrolyte-resistant resin 12. Therefore, it can be said that the embodiment as shown is more advantageous.

As described above, according to the present invention, molding can be divided into molding of the core material and molding of the resin covering it, so that molding can be performed even if the injection capacity of the molding machine is small. In addition, the cooling time (9), which is an important factor that determines the time required for molding, is significantly reduced. In other words, even if the cooling time for molding the core material and the cooling time for molding the resin covering it are combined, the cooling time when the core material and the resin covering it are molded together is It is shortened in comparison. In addition, the injection cavity of the electrolyte-resistant resin is narrowed due to the presence of the core material, so the density of the injection resin can be increased and a product with high quality can be obtained.

In addition, since the core material is ultimately covered with a resin that is resistant to electrolyte, the molding of the core material does not require much precision. It may be an inexpensive one. Furthermore, since the storage battery case obtained according to the present invention has an increased degree of rigidity due to the core material, it can be particularly advantageously applied to large to extra large size battery cases. In addition, during molding of electrolyte-resistant resin, resin can be injected from the inside and outside of the core material at the same time, so the pressure applied to the inside and outside of the core material is almost the same, and only a portion of the core material can be injected. The core material is not exposed to the inner surface of the molded product or the outer surface of the molded product because it is pressed against the male or female mold.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing an example of a large or extra-large storage battery case to which the present invention is advantageously applied. FIG. 8 is a diagrammatic representation 1 showing the injection process of an embodiment of the present invention.
FIG. FIG. 8 is a plan view of the storage battery case obtained by the injection process shown in FIG. 2. In the figure, l is the storage battery case, 2 is the side wall, 4 is the male type, and 5
is the female type, 6 is the core material, IO is the first gate, ti is the second goo), 1g is an electrolyte-resistant resin, 18 is a portion corresponding to the bottom wall, 1
4a is a through hole, 15 is an annular sprue projection, 16 is a portion corresponding to a side wall, 17 is a lateral projection, 18 is a height direction projection, 19 is an inner cavity, and 20 is an outer cavity. Ryo 1 Hi

Claims (3)

[Claims] (1) It has an overall shape that roughly follows the shape of a storage battery case that includes a bottom wall and a side wall extending upward from the bottom wall, and is made of a rigid material, with a predetermined wall on one side of the part corresponding to the bottom wall. A core material having an annular sprue protrusion that protrudes at a height and has a through hole in the center is prepared, and a mold is provided that has a first gate communicating with the through hole of the core material and a second gate other than the first gate. and positioning the core material in the mold, thereby making the first dart and the through hole communicate with each other, and forming cavities on both sides of the core material in the mold. , a storage battery container comprising the steps of injecting an electrolyte-resistant resin into the mold through the first and eighth gates, thereby obtaining a storage battery container in which the core material is covered with the resin. manufacturing method. (2) The core material is provided with positioning protrusions on a portion corresponding to its side wall and a portion corresponding to the upper end surface of the side wall, and these positioning protrusions and the sprue protrusion allow the core material to be positioned within the mold. A method for manufacturing a storage battery case according to claim (1), wherein the storage battery case is positioned. (3) The method for manufacturing a storage battery case according to claim (1) or (2), wherein the core material is made of a composite material containing polypropylene, and the electrolyte-resistant resin is polypropylene. .