JP3336602B2 - Battery case - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a battery case made of an integrally molded thermoplastic resin.

[0002]

2. Description of the Related Art As described in, for example, JP-A-5-154876, a case of a lead storage battery used in an automobile is generally formed of an integrally molded article of a thermoplastic resin such as polypropylene. . FIG. 7 shows an example of this type of battery case 1. The battery case 1 has side walls 3 and 4 rising from four sides of a rectangular bottom wall 2, and has a substantially rectangular parallelepiped shape, and has an opening 5 on the upper surface.
The inside of the battery case 1 is substantially parallel to the smaller side walls 4 and the larger side walls 3 and the bottom wall 2.
Are partitioned into a plurality of compartments 7 by a plurality of partition walls 6 connected to. In addition, a lid receiving flange 8 is formed over the entire outer periphery of the side walls 3 and 4. Further, a single convex portion 9 is formed on an outer surface of a corner portion between the adjacent side wall portions 3 and 4, and is formed thicker than other portions of the side wall portions 3 and 4. In order to enhance the releasability at the time of molding, the side walls 3 and 4 are inclined in a direction in which the gaps are increased toward the opening 5, and each partition 6
Is gradually thinner toward the opening 5.

[0003]

Generally, injection molding of a thermoplastic resin is performed by repeating an injection step, a pressure-holding step, a cooling step, a mold opening step, a removal step, and a mold closing step. In the injection step, molten resin is injected from the injection molding machine into the closed mold, and in the pressure-holding step, the resin is injected from the injection molding machine A predetermined pressure is applied to the resin. Then, after the molded article is sufficiently cooled and solidified through the cooling step, the mold is opened,
The molding is removed. Thereafter, the mold is closed again and the molding is repeated.

[0004] In order to improve the productivity, it is necessary to shorten the above molding cycle, but the cooling step takes a relatively long time, which hinders the shortening of the molding cycle. However, if the molded product is taken out in a state where it has not been sufficiently cooled, the molded product may be deformed and the accuracy may be reduced due to cooling in an unconstrained state. There is a need. In order to shorten the cooling time, it is conceivable to lower the cooling temperature of the cooling water passed through the mold, but this has a limit depending on the shape of the molded product.

Another means of reducing the cooling time is to reduce the amount of resin by making the molded article thinner. On the other hand, making the molded product thinner has a problem of a decrease in strength. Therefore,
In the battery case 1 shown in FIG. 7, in order to prevent the strength from being reduced as much as possible while reducing the thickness of the side walls 3 and 4, a convex portion 9 is formed on the outer surface of the corner between the adjacent side walls 3 and 4. Thus, this corner is formed thick. However, the corners between the side walls 3 and 4 which are thickened over a relatively wide range still cause a delay in cooling, and further improvement is desired. The time required for cooling is different between the thin portion and the thick portion. In the part 4, there is also a problem that the central part is easily deformed inwardly.

An object of the present invention is to solve such a problem, and an object of the present invention is to provide a battery case capable of shortening a molding cycle and improving dimensional accuracy without reducing strength. is there. It is a further object of the present invention to increase the internal capacity and improve the agitation of the internal solution in this battery case.

[0007]

SUMMARY OF THE INVENTION The present invention is to achieve the above object, and the invention of claim 1 comprises an integrally molded article of a thermoplastic resin, and comprises a bottom wall portion and a bottom wall portion. and a plurality of side wall portions rising from respective sides, in a battery case is open upper surface, forming a plurality of protrusions on the outer surface of the corner between the side wall portions adjacent the recesses between these protruding portions Formed and the inner surface of the side wall corresponds to the protrusion of the outer surface
A concave portion is formed at a position where the light beam is to be formed .

[0008] Even when the side wall is made thin, the strength is ensured by the protrusions at the corners between the adjacent side walls. In addition, the convex portion is divided into a plurality of portions, and a concave portion is formed between these convex portions, thereby increasing the number of thin portions while preventing a decrease in strength.
Thus, the amount of resin as a material is also reduced, and the time required for cooling when molding the battery case is reduced. Further, since the cooling of the entire side wall portion progresses more uniformly due to the concave portion between the convex portions, deformation due to uneven cooling is prevented. And the convex part and concave part are
On the outer surface, the release resistance increases more than on the inner surface.
Can be suppressed. Furthermore, in addition to the recesses on the outer surface,
By forming recesses on the surface, even thinner
It is trying to make it. The recess on the inner surface of the side wall is
Extremely thin part is provided at the position corresponding to the convex part
And prevent a decrease in strength, and have a uniform thickness
In this way, the progress of cooling during molding is made uniform.
In addition, the internal capacity is increased by providing a concave portion on the inner surface.
In addition, the effect of stirring the content liquid can be obtained.

According to a second aspect of the present invention, there is provided a battery case having a bottom wall, a plurality of side walls rising from each side of the bottom wall, and an open top surface. forming a convex portion on the inner surface <br/> plurality of corners between adjacent side wall portions, a recess between these protrusions, in a planar shape over the whole outer surface of the side wall portions It is formed .

As described above, when the side wall portion is made thin,
The strength is also ensured by the protrusions at the corners between adjacent side walls.
Is preserved. Moreover, the convex portion is divided into a plurality of
A recess is formed between the parts to prevent the strength from decreasing
Have many. As a result, the amount of resin,
To cool down when molding the battery case.
Time is shorter. In addition, the concave portion between the convex portions
Does the cooling of the entire wall proceed more uniformly?
Moreover, deformation due to uneven cooling is prevented. When a plurality of convex portions and concave portions between them are formed on the inner surface of the side wall portion, an effect of stirring the content liquid can be obtained. In addition, since the battery case has a standard for the external dimensions, if the outer surface of the side wall portion is made to be entirely flat, the inner capacity is increased by reducing the thickness of the side wall portion in portions other than the convex portion.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a battery case according to the present invention will be described.
A reference example will be described with reference to FIGS. 11 is a battery case made of a thermoplastic resin integrally molded product, 12 is its bottom wall, 13 and 14 are side walls, 15 is an opening, 16 is a partition, 17 is a compartment, and 18 is a lid receiving flange. Yes,
Since these basic configurations are the same as those of the conventional battery case 1 shown in FIG. 7 described above, the description thereof is omitted. In the battery case 11 of this reference example, the corners of the adjacent side wall portions 13 and 14, raised portion 20 is formed on the outer surface, which is slightly thicker than the rest of the side wall portions 13 and 14. In addition, the battery case 11
A plurality of protrusions 21 formed of protrusions along the height direction are formed, and a groove-like recess 22 is formed between these protrusions 21. The convex portion 21 is also at a ridge between the adjacent side walls 13 and 14. The battery case 11 has a standard for its outer dimensions (width W and length L), and the width W and length L are
This is applied to the projection 21.

Reference numeral 26 denotes an opening 15 of the battery case 11.
The lid 26 has a side wall 27 that fits on the outside of the side walls 13 and 14 of the battery case 11 and is placed on the lid receiving flange 18.

[0013] In the battery case 11 of the present reference embodiment, even when the side wall portions 13 and 14 in thin, there is a protrusion 21 at each corner between the side wall portions 13 and 14 adjacent the most on securing strength effective Therefore, a decrease in strength can be suppressed. In addition, since the convex portion 21 is divided into a plurality of portions and the concave portion 22 is formed between these convex portions 21, a thin portion can be increased while preventing a decrease in strength. This can reduce the amount of thermoplastic resin in the material,
Since the material can be saved, and the cooling is performed promptly during the molding, the molding cycle can be shortened and the productivity is improved. At the same time, the accuracy of the molded battery case 11 improves due to the improvement of the cooling effect. Further, there is a concave portion 22 between the convex portions 21, and the side wall portions 13, 14
By making the thickness more uniform, the cooling of each part of the side wall parts 13 and 14 progresses more uniformly, deformation due to uneven cooling can be prevented, and the accuracy of the battery case 11 is further improved. .

The presence of the convex portion 21 and the concave portion 22 increases the contact area between the battery case 11 having the contact area and the mold, and is a factor that increases the release resistance of the battery case 11 during molding. Becomes However, in general, the shrinkage due to cooling, the molded products, since the mold release resistance against mold for forming the inner surface is greater than the mold release resistance against mold for forming the outer surface, the reference actual <br / As shown in the embodiment, if the convex portion 21 and the concave portion 22 are provided on the outer surface of the battery case 11, an increase in the release resistance can be suppressed as compared with the case where the convex portion and the concave portion are provided on the inner surface.
11 can be released smoothly. And the battery case
The mold that forms the outer surfaces of the side walls 13 and 14 of the 11 can be made of a slide core, for example, to make it easier to release the battery case 11 from the mold.

Next, the first case of the battery case of the present invention will be described.
An embodiment will be described with reference to FIGS. 31 is a battery case made of an integrally molded thermoplastic resin, 32 is its bottom wall, 33 and 34 are side walls, 35 is an opening, 36 is a partition, 37 is a compartment, 38 is a lid receiving flange, Reference numeral 40 denotes a raised portion. The basic configuration of these components is the same as that of the battery case 11 of the reference embodiment, and a description thereof will be omitted. Also, in the battery case 31 of the first embodiment, the outer surfaces of the corners of the adjacent side walls 33 and 34 are also provided on the outer surfaces of the corners.
A convex portion 41 and a concave portion 42 similar to those of the reference example are formed. Further, in the first embodiment, groove-shaped concave portions 43 are formed on the inner surfaces of the side wall portions 33 and 34 at positions corresponding to the respective convex portions 42 on the outer surface.

A cover 46 and a side wall 47 are the same as the cover 26 and the side wall 27 of the reference embodiment.

According to the battery case 31 of the first embodiment, in addition to the concave portions 42 on the outer surfaces of the side walls 33, 34, the side walls 33, 34 are provided.
Since the recess 42 is also formed on the inner surface of the side wall 34, these side walls 33,
34 can be made even thinner. Moreover, the concave portion 42 on the inner surface
Are provided at positions corresponding to the convex portions 41 on the outer surface, and the side wall portions 33 and 34 are provided.
Since the corners between them are formed in a corrugated cross section, extremely thin portions are not formed on the side walls 33 and 34, and a decrease in strength can be prevented. At the same time, the thickness of the side walls 33 and 34 becomes more uniform,
The progress of cooling at the time of molding also becomes more uniform at each of the side wall portions 33 and 34. Therefore, the accuracy of the molded battery case 31 can be further improved.

A concave portion 42 is formed on the inner surface of the battery case 31.
Is formed, the capacity of the battery case 31 increases,
In addition, the effect of improving the agitation property of the content liquid can be obtained by the concave portion 42 on the inner surface in contact with the content liquid.

Next, the second case of the battery case of the present invention will be described.
An embodiment will be described with reference to FIGS. 51 is a battery case made of an integrally molded thermoplastic resin, 52 is its bottom wall, 53 and 54 are side walls, 55 is an opening, 56 is a partition, and 57 is a compartment. Is the same as the battery case 11 of the reference embodiment and the first embodiment, and the description thereof will be omitted. In the battery case 51 of the second embodiment, an upwardly facing lid receiving stepped portion 58 is formed on the upper portion of the inner surface of the side wall portions 53 and 54. In addition, a plurality of protrusions 61 formed of protrusions along the height direction of the battery case 51 are formed on the inner surface of each corner of the adjacent side walls 53 and 54, and a groove is formed between the protrusions 61. Recess 62 is formed. The concave portion 62 is also at a valley between the adjacent side wall portions 53 and 54. Further, the outer surfaces of the side walls 53 and 54 are formed in a planar shape over the whole.

Reference numeral 66 denotes an opening 55 of the battery case 51.
The lid 66 has a side wall 67 that fits inside the side walls 53 and 54 of the battery case 51 and is placed on the lid receiving step 58, and the side walls 53 and 54. A flange 68 placed on the upper end of 54 is provided outside the base of the side wall 67.

In the second embodiment as well, similar to the reference embodiment and the like, a plurality of convex portions 61 and concave portions 62 are provided at each corner between the adjacent side walls 53 and 54, so that the strength is reduced. While suppressing the amount of the resin material, the molding cycle can be shortened and the effect of improving the accuracy can be obtained. In addition, in the second embodiment, the convex portions 61 are provided on the inner surfaces of the side wall portions 53 and 54, and the outer surfaces of the side wall portions 53 and 54 are formed to be entirely flat. If the external dimensions (width W and length L) are the same, the battery case is reduced by the thickness of the side walls 53 and 54 at portions other than the protrusion 61 than when the protrusion is provided on the outer surface.
11 contents increase. Therefore, the performance as a battery is also improved. Further, by the convex portion 61 and the concave portion 62,
Since the stirring property of the content liquid is improved, the performance as a battery is further improved. Further, since the outer surfaces of the side walls 53 and 54 are entirely flat, printing can be performed on the entire outer surfaces of the side walls 53 and 54 when printing is performed.

By the way, as described above, the formation of the protrusions 61 and the recesses 62 on the inner surface of the battery case 51 is a factor that impairs the releasability of the battery case 51 during molding. Therefore, as shown in the figure, it is desirable that the convex portion 61 and the concave portion 62 on the inner surface are formed into a smooth curved surface such as a cylindrical surface, and the protrusion amount t of the convex portion 61 is as small as possible. The same applies to the concave portion 43 on the inner surface of the battery case 31 of the first embodiment.

It should be noted that the present invention is not limited to the above embodiment, and various modifications can be made. For example,
The shapes of the convex portions and the concave portions are not limited to those illustrated, and the convex portions and the concave portions on the outer surface may be curved. In the above embodiment,
Although the convex portions and the concave portions are formed only at the corners of the adjacent side wall portions, the convex portions and the concave portions may be formed over the entire side wall portion including the corner portions. In this case, in order to reduce the wall thickness, it is preferable to make the inner and outer surfaces of the side wall portions uneven as in the first embodiment.

[0024]

Effects of the Invention According to the battery case of the invention of claim 1, to form a plurality of protrusions on the outer surface of the corner portion between the adjacent side wall portion, since the recesses between these protruding portions, A wide range of the side wall portion can be formed to be thin while minimizing a decrease in strength. Therefore, during the molding, the cooling is performed quickly, so that the molding cycle can be shortened, the productivity is improved, and the accuracy of the molded battery case is also improved by improving the cooling effect and making the cooling uniform. In addition, since the amount of resin as a material is reduced, material can be saved. In addition, at the time of molding, the molded battery case
Increase in mold release resistance,
The base can be released smoothly. Also, make the convex part outside the side wall part.
On the outer surface of the side wall, forming a recess between the protrusions on the outer surface.
And the inner surface of the side wall corresponds to the protrusion on the outer surface.
Since a recess is formed in the
The thickness can be further reduced, and the cooling at the corners between the side walls
Rejection proceeds more evenly, so more accuracy
Can be improved. In addition, the inner concave part increases the internal capacity
And the effect of improving the agitation of the content liquid is also obtained.
You.

According to the battery case of the invention of claim 2, a plurality of protrusions on the inner surface of the corner between the adjacent side wall portion formed
As a result, concave portions were formed between these convex portions, resulting in a decrease in strength.
While the suppressing electrode force, can form a wide range of side wall portions thinner
You. Therefore, during molding, cooling is performed promptly.
Molding cycle can be shortened, and productivity can be improved.
As well as improving the cooling effect and making the cooling uniform.
As a result, the accuracy of the molded battery case is also improved. Ma
In addition, the amount of resin used in the material is reduced, which saves material.
You. Further, the convex portion is formed on the inner surface of the side wall portion, and the outer portion of the side wall portion is formed.
Because the surface was formed flat over the entire surface,
If the case is the same, the content will be better than if a convex part is provided on the outer surface.
The volume can be increased, and the inner surface convex and concave portions
The stirring property of the solution is improved. Furthermore, the outer surface of the side wall is
That the entire outer surface of the side wall is
There is also the effect of enabling printing on the body.

[Brief description of the drawings]

FIG. 1 is a horizontal sectional view showing a reference example of a battery case of the present invention.

FIG. 2 is a sectional view taken along line II-II of FIG.

FIG. 3 is a horizontal sectional view showing a first embodiment of the battery case of the present invention.

FIG. 4 is a sectional view taken along line IV-IV of FIG. 3;

FIG. 5 is a horizontal sectional view showing a second embodiment of the battery case of the present invention.

6 is a sectional view taken along line VI-VI of FIG.

FIG. 7 is a perspective view showing an example of a conventional battery case.

[Explanation of symbols]

 31, 51 Battery case 32, 52 Bottom wall 33, 53 Side wall 34, 54 Side wall 35, 55 Opening 41, 61 Convex 42, 62 Concave 43 Concave

Claims (2)

(57) [Claims] 1. A battery case comprising an integral molded article of a thermoplastic resin, comprising a bottom wall, a plurality of side walls rising from each side of the bottom wall, and an open top.
Forming a plurality of protrusions on the outer surface of the corner between the adjacent side wall portions, a recess is formed between these projecting portions, of the side wall portions
A battery case , wherein a concave portion is formed at a position corresponding to the convex portion on the outer surface . 2. A battery case comprising an integral molded article of a thermoplastic resin, comprising a bottom wall, a plurality of side walls rising from each side of the bottom wall, and having an open top.
Forming a plurality of protrusions on the inner surface of the corners between adjacent side wall portions, a recess between these protrusions, the outer of said side wall portion
A battery case characterized in that the surface is formed in a flat shape over the whole .