JPH0414847Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] This invention relates to a storage battery case obtained by injection molding, and is particularly aimed at improving the strength of a storage battery case of a large or extra-large single-cell storage battery. This is related to improvements to achieve this goal.

[Prior art] For example, the length, width, and height dimensions are each approximately 50
The containers for large storage batteries, such as 45 cm, 45 cm, and 90 cm, are most commonly made of ebonite, but in recent years advances in molding technology have led to the use of materials such as acrylonitrile styrene (AS) resin, acrylonitrile styrene (AS) resin, etc. Butadiene styrene (ABS)
It has come to be formed from resin by injection molding.

[Problems to be Solved by the Invention] However, when trying to obtain the above-mentioned large-sized battery case by injection molding, the following problems were encountered.

First, when the resin injection is finished and the product is released from the mold, negative pressure is created especially between the male mold and the inner surface of the molded product.
Each side wall of the molded product, ie, the battery case, is deformed so as to curve inward. Usually, a mold is formed with a scent to facilitate mold release, and due to the presence of such a scent, for example, during the process of pulling out the male mold, the male mold and the inner surface of the molded product inevitably come into contact with each other. There will be a gap in between. Therefore, the negative pressure generated between the male mold and the inner surface of the molded product will eventually be released, but in the case of large battery containers, especially those with a large height dimension, the side wall of the molded battery container However, it was found that the mold remained in close contact with the male mold for a relatively long period of time during the drawing process of the male mold, and the negative pressure mentioned above was not released very quickly. Therefore, in large-sized battery containers, the inward curvature of the side walls was particularly noticeable after molding.

In addition, even after the battery is completed, in addition to the weight of the electrolyte and electrode plates, during initial charging, the side walls of the battery case tend to curve outward due to the heat generated and the internal pressure of the hydrogen gas generated. It sometimes deformed into

The above-mentioned side wall curvature may be solved to some extent by, for example, increasing the side wall thickness, but in this case, the injection capacity of the molding machine must be increased, which requires an enormous amount of investment in the molding equipment. have to incur significant costs. In addition, it takes a long time for the injected resin to solidify, lowering productivity, and causing so-called "sink marks" as a defect in molding to appear prominently. Other problems also arise, such as increased material costs and increased weight of the battery case.

As another means for preventing the above-mentioned curvature of the side wall, it is conceivable to form ribs integral with the side wall formed by injection molding, as described in, for example, Japanese Utility Model Publication No. 38-9328. just,
The storage battery disclosed in the utility model publication is not large. This is because, at that time, large battery cases were always made of ebonite. When forming ribs as in this conventional technique is applied to large battery containers, the smooth flow of the injected resin is obstructed, air bubbles, weld lines, flow marks, etc. appear prominently, and molding This will reduce the quality of the product, that is, the battery case.

In addition, in cases where the battery case has a plurality of partition walls, the partition walls are molded integrally with the battery case, so such partition walls can prevent the side walls from curving as described above to some extent. However, the case of a stationary storage battery having the above-mentioned dimensions is usually of a single-cell structure. Therefore, in a single large battery case, the curvature of the side wall becomes particularly noticeable.

Therefore, this invention aims to provide a storage battery case that can solve the above-mentioned problems in injection molding and charging of a completed storage battery.

[Means for solving the problem] This invention is obtained by injection molding, has a rectangular cross section with four side walls, and has a pole located at a relatively upper position on the inner surface of a pair of opposing side walls. The technical problem described above is solved as follows in a single tank storage battery case in which a stepped portion for receiving a group of plates is formed.

That is, the portions of the four side walls above the step portion form a flat surface, and the portions below the step portion have approximately the same substantial thickness in the vertical direction. extending, convex part,
A shape in which the connecting step, the recess, and the connecting step are sequentially connected is continuously provided.

[Operation and effect of the invention] According to this invention, on each side wall of the battery case, a series of protrusions, connecting steps, recesses, connecting steps, etc.
Increase the apparent thickness of the side wall and increase the rigidity of the side wall. Therefore, the tendency of the side walls to be deformed to curve inwardly due to the negative pressure created by the withdrawal of the male mold in injection molding as described above is reduced. Incidentally, an increase in the rigidity of the side wall means that it can withstand the above-mentioned negative pressure, but this does not mean only that. That is, if the rigidity of the side wall is increased, the close contact between the side wall and the male mold can be released more quickly during the process of pulling out the male mold, and the period during which negative pressure is generated can be further shortened. Therefore, the forces that cause the side walls to curve inward can be removed more quickly, and curves are less likely to occur.

The increased stiffness of the sidewalls also prevents the tendency of the sidewalls to deform outwardly during charging of the completed battery.

Moreover, according to this invention, the rigidity of the side wall can be increased without increasing the actual wall thickness so much. Therefore, "sink", which is a problem in injection molding, is less likely to occur, and since it does not take much time to solidify the injected resin, it is possible to prevent a decrease in productivity. Of course, it is also possible to prevent an increase in material costs and an increase in the weight of the battery case.

In addition, according to this invention, since the actual wall thickness of each side wall is approximately equal, the flow of the injected resin within the mold is smooth and approximately uniform at each location, so it is possible to prevent molding problems such as weld lines and flow marks. The occurrence of defects can be suppressed.

In addition, according to this invention, the portion of each side wall above the step portion forms a flat surface, which is suitable for printing the storage battery manufacturer, type code, etc. can give an aspect.

[Example] As shown in FIG. 1 as a front view and as shown in FIG. 2 as a left side view, a storage battery case 1 as an example of this invention is obtained by injection molding.
side walls 2 to 5 and a bottom wall 6. The battery case 1 has a rectangular cross section in plan view.

Extending from the upper end of the pair of side walls 4 and 5 of the battery case 1,
A pair of hanging handles 7 are provided protruding from the upper end surface of the battery case 1. Each hanging handle 7 has two
Hanging holes 8 are formed side by side. Pins provided for hanging tools (not shown) are inserted into these hanging holes 8. This kind of storage battery equipped with a large battery case 1 has a weight of, for example, about 450 kg, so when transporting it, a lifting device such as a crane is used, and the storage battery is lifted via a hanging device. be lifted up.

A lid step 9 is formed on the inner surface of the upper end of the battery case 1 . This stepped portion 9 is for holding and positioning a lid (not shown) for closing the top opening of the battery case 1.

A step portion 10 for receiving a group of electrode plates housed in the battery case 1 is formed at a relatively upper position on the inner surfaces of the pair of opposing side walls 2 and 3. Such a configuration is generally employed in large-sized storage batteries. Furthermore, a saddle 11 for supporting the above-mentioned electrode plate group is provided on the upper surface of the bottom wall 6 so as to protrude upward.

Furthermore, a spacer 12 separate from the battery case 1 is fitted into the lower surface of the bottom wall 6. These spacers 1
2 functions as a leg portion of the battery case 1.

Each side wall 2 to 5 shown in FIG. 1 and FIG.
If you pay attention to the area below the step 10, you will notice that some unevenness appears there. In addition, the first
Enlarged cross-sectional views taken along the figures lines - and -, respectively, are shown in FIGS. 3 and 4.

As can be seen from these drawings, for example, in the case of the side walls 2 and 3, a convex portion 13, a connecting step 14, a recess 15, and a connecting step 16 extend in the vertical direction from one side to the other side. , convex portion 17,
The connecting step 18, the recess 19, the connecting step 20, and the convex portion 21 are successively connected. Note that in this specification, "convex portions" and "concave portions" respectively correspond to concavities and convexities when viewed from the outer surface of the battery case 1. These convex parts 13, 17, 21, connection step 1
4, 16, 18, 20, and recesses 15, 19
As shown in Figures 3 and 4,
They are formed with substantially equal wall thickness.

In addition, the other two side walls 4 and 5 have substantially the same substantial thickness below the step portion 10,
Convex portion 22 and connecting step 2, each extending in the vertical direction
3. Concave portion 24, connection step 25, convex portion 26, connection step 27, recess 28, connection step 29, and convex portion 30
A shape in which these are connected in sequence is given in succession.

The above-described uneven shape provided on each of the side walls 2 to 5 increases the apparent thickness of the side walls 2 to 5, and accordingly increases the rigidity. Further, the location where such an uneven shape is provided is selected below the position of the stepped portion 10, but this is because, as mentioned above, it is necessary to prevent curvature during the injection molding process.
A portion below the step portion 10, which is susceptible to the negative pressure generated at the initial stage of drawing out the male die;
That is, this is because it is a relatively lower part of the battery case 1.

In addition, in the illustrated embodiment, as can be seen from FIGS. 3 and 4, each connecting step 23, 25, 2 formed on one pair of opposing side walls 4, 5
7 and 29 are the other pair of opposing side walls 2 and 3;
Each connection step 14, 16, 18, 20 formed in
The dimensions are chosen to create a larger step difference between the associated protrusions and recesses compared to the above. This is because the side walls 4 and 5 will receive a greater pressure load from the electrode plates (not shown) housed in the battery case 1, so they can withstand it. It is.

Further, in the recesses 24 and 28 formed in the pair of opposing side walls 4 and 5, slightly protruding ribs 3 are provided, as clearly shown in FIGS. 2 and 3.
1 is formed. These ribs 31 are for positioning the electrode plate group, but they also contribute to improving the strength of the side walls 4 and 5, albeit slightly. However, such improvement in strength by the ribs 31 is not essential to this invention.

This invention has been described above in connection with the illustrated embodiment, but the convex portion formed on one side wall,
The number of connecting steps, recesses, and series of connecting steps can be changed arbitrarily depending on the size of the battery case or design issues.

Also, as in the illustrated embodiment, each side wall 2 to 5
By forming a flat surface above the step 10, it is possible to provide a surface suitable for printing the storage battery manufacturer, type code, etc.

[Brief explanation of drawings]

FIG. 1 is a front view showing a battery case 1 according to an embodiment of this invention, and the left half thereof is shown in a sectional view. FIG. 2 is a left side view of the battery case 1 shown in FIG. 1, and the right half thereof is shown in a sectional view. FIG. 3 is an enlarged sectional view taken along line - in FIG. 1.
FIG. 4 is an enlarged sectional view taken along line - in FIG. 1. In the figure, 1 is a battery case, 2 to 5 are side walls, 10 is a stepped portion, 13, 17, 21, 22, 26, 30 are convex portions, 14, 16, 18, 20, 23, 25, 2
7 and 29 are connecting step portions, and 15, 19, 24, and 28 are recessed portions.

Claims (1)

[Claims for Utility Model Registration] (1) Obtained by injection molding, having a rectangular cross section with four side walls, and receiving a group of electrode plates at a relatively upper position on the inner surface of a pair of opposing side walls. In a single-tank storage battery case in which a step is formed for the storage, the portions of the four side walls above the step may form a flat surface, and the portions below the step may form a flat surface. A storage battery case characterized in that a convex portion, a connecting step, a concave portion, and a connecting step are sequentially connected to each other and have substantially the same substantial wall thickness and each extend in the vertical direction. . (2) Of the four side walls, each of the connecting steps formed on a pair of opposing side walls that receive a larger pressure load caused by the electrode plate is different from the other one.
The storage battery according to claim 1, wherein dimensions are selected to create a larger step difference between the protrusion and the recess than each of the connection steps formed on the paired side walls. Electric tank.