JP2005190796A - Battery case for storage battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a battery case for a storage battery which can be formed simply and strength of whose side can be improved. <P>SOLUTION: The inside of the battery case for the storage battery which is made of a rectangular box shape having a short side, a long side, and a bottom with the upper side of the bottomed box opened and made by forming synthetic resin is demarcated in six cell chambers by barrier ribs, and a recessed section extending in the height direction of the battery case is formed at the short side by bending the short side. The recessed section may be one piece or a plurality of pieces may be formed. Furthermore, ribs extending in the height direction of the battery case same as the recessed section are formed in the recessed section. These ribs may be one piece or plural pieces. By forming such kind of recessed section by bending, the battery case having a strength stronger than the one forming many ribs only in the height direction on the short side or the one forming the ribs only in the width direction, or the one forming the ribs in lattice form, can be obtained. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a battery case for a storage battery in which the lateral strength of the battery case is improved.

  A battery case for a storage battery is manufactured by molding a synthetic resin such as propylene, and contains an electrode plate group and an electrolytic solution from the opened upper surface, and is used as a storage battery with a lid. The battery case side tends to bulge during use. This phenomenon is seen on the short side surface, which is relatively wide, for example, in a monoblock type battery case in which one cell case is partitioned into a large number of cell chambers. There is a method of improving the strength of the. In order to improve the strength of the side surface, in addition to the method of increasing the thickness of the side surface of the battery case, longitudinal ribs are formed on the side surface and ribs are formed in a lattice shape in the longitudinal and lateral directions (Patent Document 1) and a reinforcing plate (Patent document 2) etc. are performed.

Patent Document 1 Japanese Patent Laid-Open No. 9-306437 Patent Document 2 Japanese Patent Laid-Open No. 8-273638

  The strength of the side surface of the battery case can be improved by the conventional method. However, each has advantages and disadvantages, and increasing the thickness of the side surface can improve the strength in any way depending on the thickness, but there is a problem that the outer shape of the battery case becomes large and the amount of resin used increases. The method of forming only the ribs in the vertical direction can improve the strength as such, but its bulge-inhibiting power is somewhat insufficient, and as in recent years, many active materials are filled into the electrode plate to increase the capacity. This is stored in the battery case, and further improvement in strength is desired. The formation of grid-like ribs can improve the strength higher than that of vertical ribs alone, but it is not possible to use a molding die called a die that can be molded relatively easily in the molding of battery cases. There are problems such as being expensive. In addition, the provision of the reinforcing plate has a problem that a separate part is required and the mounting operation is troublesome.

  The present invention has been made to solve these problems, in which the side wall of the battery case is bent to form a concave portion, and further, a vertical rib is formed in the concave portion.

  Accordingly, a punching die can be used as the molding die, and the strength of the side surface can be improved as compared with the case where only the vertical rib is formed.

  According to the present invention, the battery case for the storage battery can be easily formed, and at the same time, the effect of improving the strength of the side surface can be achieved.

FIG. 1 is a partial perspective view of a storage battery battery case showing an embodiment, and FIG. 2 is a partial sectional view thereof.
As shown in the figure, the battery case 1 is formed of a rectangular box-like body having a bottomed upper surface consisting of a short side surface 1a, a long side surface 1b, and a bottom surface, and the side wall is bent to the short side surface 1a and projects outward. A concave portion 2 was formed. In the illustrated example, two concave portions 2 are formed. The concave portion 2 was formed in the vertical direction of the battery case 1.

  Two ribs 3 were formed in the concave portion 2 in the vertical direction. These concave portions 2 and ribs 3 are integrally formed when the battery case 1 is formed, but since there are no protrusions on the side surfaces in the left-right direction, the protrusions 1c on the top of the battery case 1 are used as a boundary in the vertical direction as in the conventional case. It can be easily formed by a punching die.

  A battery case having the above size was used as a battery case for a storage battery, and a battery case in which the inside was divided into six cell chambers 4 by partition walls 1d was molded from polypropylene resin. The size of the battery case was about 204 mm in height, 173 mm in width, and 260 mm in length. The thickness of the short side surface 1 a and the long side surface 1 d was 4 mm on the short side surface and 3 mm on the long side surface.

  The partition wall 1d has a thickness of 1.4 mm. Reference numeral 1e denotes a small protrusion provided on the inner surface of the short side surface 1a or the partition wall 1d.

  In the height direction of the short side surface 1 a of the battery case 1, the side surface was bent 90 degrees in a U-shaped manner, and two concave portions 2 were provided at positions almost equally dividing the short side surface in the width direction. The short side surface 1a is formed in such a manner that the cell width of the upper surface of the cell chamber 4a at the end is increased so that the short side surface protrudes into the cell chamber 4 and is bent into the inner surface of the upper short side wall. The inner surface of part 2 was made to be the same surface.

  The concave part 2 is formed from the lower part of the protruding part 1c formed on the entire outer periphery of the upper part of the battery case to reach the lower end of the battery case, the width is 22 mm, the concave part depth is 3 mm, and two ribs 3 are formed therein. did. The thickness of the rib 3 is 2 mm.

  A battery case similar to that of Example 1 was prepared except that one concave portion 2 was formed at the center in the width direction of the short side surface 2 as the battery case.

  The same thing as Example 1 was created except not having formed a rib in the concave part of the short side of a storage battery case.

  The same thing as Example 2 was created except not having formed the rib in the concave part of the short side of the storage battery case.

Comparative example

  16 ribs having a thickness of 2 mm are formed on the outside of the short side of the battery case for the storage battery, and 16 similar ribs are formed on the outside of the short side in the width direction. On the outside, similar ribs were formed in a lattice pattern in both the height and width directions (the thickness of the ribs and the number of ribs are the same as those of the vertical and horizontal ribs).

Conventional example

  As a conventional example, a flat surface that does not form ribs or the like on the short side surface of the battery case was prepared.

A lid was fused and sealed to each of these battery cases, and a pipe was hermetically passed through the lid, and air was fed through the pipes into all cell chambers in the battery case and pressurized at 0.8 kgf / cm2.
Table 1 shows the results of measuring the deformation amount (maximum bulging dimension) of the short side surface by pressurization.

As is apparent from Table 1, those using the battery case of the present invention are those having vertical ribs, horizontal ribs or lattice ribs shown as comparative examples, and flat ones without ribs shown as conventional examples. Thus, a battery case having a smaller deformation amount was obtained, and a battery case having improved strength was obtained.
In the above embodiment, the bending angle is 90 degrees. In this case, when the angle is best reduced to 80 or 70 degrees, the bulge size tends to be large, that is, the strength tends to decrease, and 80 to 90 degrees is preferable. In addition, the number of the concave portions is best in the battery case having the size described in the above embodiment, and when three are formed, the bulging dimension is slightly larger than that in the case of one.

FIG. 1 is a perspective view of an embodiment of the present invention.
2 is a partial cross-sectional view taken along the line AA in FIG.

Explanation of symbols

1 battery case 1a short side surface 2 concave portion 3 rib

Claims (2)

A battery case for a storage battery in which a concave portion is formed by bending the side wall of the battery case. The battery case for a storage battery according to claim 1, wherein a rib is formed in the concave portion.

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