JP2005317391A - Battery pack and manufacturing method of battery pack - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a battery pack in which adhesion strength is stabilized by providing a plurality of projections at the top of adhesion rib, and a manufacturing method of the battery pack. <P>SOLUTION: The battery pack 10 is provided with a first case half body 12 which has a bottom and side walls and adhesion ribs of projection shape formed at the top of the side walls, a second case half body 14 which has a bottom and side walls and an adhesion face to be adhered with the adhesion ribs formed at the top of the side walls, and a battery 10 which is housed in the first case half body 12 and the second case half body 14 adhered with the adhesion ribs and the adhesion face. A plurality of projections are installed in thickness direction at the tops of the adhesion ribs. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention includes a first case half having a protruding welding rib, a second case half having a welding surface to which the welding rib is welded, and a first case half in which the welding rib and the welding surface are welded. The present invention relates to a battery pack comprising a body and a battery housed in a second case half, and a method for manufacturing the battery pack.

  As a driving power source for a small electronic device or a portable electronic device, a battery pack in which a battery to which a protective circuit board is attached is housed in a synthetic resin case is used. FIG. 1 is an exploded perspective view showing an example of a battery pack before welding. The case includes a first case half 12 and a second case half 14 having a bottom and a side wall, and the first case half 12 and the second case half 14 are integrated by ultrasonic welding or the like. The battery 10 is accommodated.

  5 (a) to 5 (c) and FIGS. 6 (a) to 6 (b) are cross-sectional views taken along line AA in FIG. 1 showing a conventional example of welding of the first case half 12 and the second case half 14. FIG. It is sectional drawing. However, the battery 10 is omitted. As shown in FIG. 5A, a protruding welding rib 16 is formed at the front end of the side wall of the first case half 12, and the welding rib 16 is welded to the front end of the side wall of the second case half 14. A welding surface 18 is formed. As shown in FIG. 5 (b), the welding rib 16 is brought into contact with the welding surface 18, and vibration is applied to the first case half 12 from the ultrasonic horn 20, whereby the welding rib 16 and the welding surface 18 are subjected to frictional heat. As shown in FIG. 5 (c), it is welded to the welding surface 18.

However, as shown in FIG. 6A, the position of the welding rib 16 may be shifted due to the pressure or vibration applied to the first case half 12 from the ultrasonic horn 20. For example, the welding rib 16 may fall from the welding surface 18 to the inside of the case and normal welding may not be performed, resulting in a reduction in welding strength. Therefore, in order to prevent the welding rib 16 from falling from the welding surface 18, for example, as shown in FIG. 6B, a drop prevention rib 22 is provided on the inner edge side of the welding surface 18. As another method, a V-shaped projection having a V-shaped cross section (hereinafter referred to as a vertical cross section) perpendicular to the circumferential direction of the first case half 12 is formed at the tip of the welding rib 16 and welded. A V-shaped groove having a V-shaped longitudinal section is formed on the surface 18 (see, for example, Patent Document 1).
JP 2002-245993 A

  In recent years, along with miniaturization of small electronic devices or portable electronic devices, there is a strong demand for smaller and lighter battery packs built into the electronic devices. In order to reduce the size and weight, it is necessary to reduce not only the battery but also the case. As a method for reducing the size and weight of the case, it is conceivable to reduce the thickness of the side wall of the case half, but when the thickness of the side wall of the case half is reduced, the width of the welding surface decreases, Ribbing of the ribs is likely to occur. In addition, when the fall prevention rib is provided at the inner edge of the welding surface, the thickness of the side wall of the case half is increased, which is disadvantageous for making the case smaller and lighter.

  In addition, when forming a V-shaped groove on the welding surface, it becomes more difficult to form the V-shaped groove as the thickness of the side wall is reduced. Therefore, there is a high possibility that the manufacturing cost of the case will increase, or that the defective rate of the case will increase due to the formation failure of the V-shaped groove. In addition, when the formation accuracy of the V-shaped groove is not maintained uniformly, it is necessary to adjust the tip of the welding rib to be positioned in the V-shaped groove, and it is highly likely that it takes time to manufacture the battery pack. .

  The present invention has been made in view of such circumstances, and provides a battery pack and a method of manufacturing the battery pack in which the welding strength is stabilized by providing a plurality of protrusions in the thickness direction of the tip end portion of the welding rib. With the goal.

  Another object of the present invention is to provide a battery pack in which the welding strength is further stabilized by providing three or more protrusions in the thickness direction of the tip portion of the welding rib.

  In addition, the present invention provides a method for manufacturing a battery pack in which the welding strength is further stabilized by making the longitudinal section of the plurality of protrusions (a section in a direction perpendicular to the circumferential direction of the first case half) trapezoidal. To do other purposes.

  Another object of the present invention is to provide a battery pack in which the welding strength is further stabilized by providing a recess having a semicircular or trapezoidal longitudinal section between the plurality of protrusions.

  A battery pack according to a first aspect of the present invention includes a first case half having a bottom and a side wall, and a protruding welding rib formed at a front end of the side wall, a bottom and a side wall, and the front end of the side wall A second case half formed with a welding surface on which the welding rib is welded, and a battery accommodated in the first case half and the second case half welded to the welding rib and the welding surface. In the battery pack, the tip of the welding rib has a plurality of protrusions in the thickness direction.

  The battery pack according to a second aspect of the present invention is characterized in that, in the first aspect, the tip end portion of the welding rib has three or more protrusions in the thickness direction.

  A battery pack according to a third aspect of the present invention is characterized in that, in the first or second aspect, a cross section of the plurality of protrusions in a direction orthogonal to a circumferential direction of the first case half is trapezoidal.

  The battery pack according to a fourth aspect of the present invention is the battery pack according to any one of the first to third aspects, wherein the recess in the direction perpendicular to the circumferential direction of the first case half is semicircular or trapezoidal between the plurality of protrusions. Is provided.

  According to a fifth aspect of the present invention, there is provided a battery pack manufacturing method comprising: a first case half having a bottom and a side wall, wherein a protruding welding rib is formed at a tip of the side wall; and a bottom and a side wall. And a battery housed in the first case half and the second case half in which the welding rib and the welding surface are welded to each other. In the manufacturing method of a battery pack comprising: a first case half body provided with a plurality of protrusions in the thickness direction of the tip end portion of the welding rib.

  In the first and fifth inventions, when a plurality of protrusions are provided in the thickness direction at the tip of the welding rib, the plurality of protrusions provided on the welding rib come into contact with the welding surface. Compared with the case where one tip part contacts the welding surface, the contact is stable, the position of the welding rib is difficult to shift, and the welding rib is difficult to fall down. Therefore, the welding strength is stabilized and it is not necessary to provide a drop prevention rib. Moreover, since it is not necessary to provide a drop-off preventing rib, the case can be thinned. Furthermore, since the welding surface may be a flat surface, the case can be easily manufactured.

  In the second invention, when three or more protrusions are provided in the thickness direction of the tip end portion of the welding rib, the welding rib comes into contact with the welding surface by three or more protrusions, so that it is easy to balance and the position of the welding rib Is more difficult to slip and the welding ribs are more difficult to fall. Therefore, the welding strength is further stabilized.

  In the third aspect of the invention, when the longitudinal section of the plurality of protrusions provided on the welding rib (the section in the direction perpendicular to the circumferential direction of the first case half) is trapezoidal, the longitudinal section is in comparison with the V-shape. Since the contact area increases, the contact with the welding surface becomes stable and the tip is hardly deformed. Therefore, the welding strength is further stabilized.

  In the fourth invention, when a recess having a semicircular or trapezoidal longitudinal cross section is provided between the plurality of projections provided on the welding rib, the stress is one point compared to the case where the vertical cross section between the projections is V-shaped. Therefore, it is difficult to tear between the protrusions. Therefore, poor welding due to tearing between the protrusions is less likely to occur, and the welding strength is further stabilized.

  According to the first and fifth inventions, the position of the welding rib is difficult to shift and the welding rib is difficult to fall down, so that the welding strength is stabilized.

  According to the second aspect of the invention, the position of the welding rib is more difficult to shift, and the welding rib is more difficult to fall down, so that the welding strength is further stabilized.

  According to the third invention, the contact with the welding surface is stable, and the tip is hardly deformed, so that the welding strength is further stabilized.

  According to the fourth invention, it is difficult to tear between the protrusions, so that the welding strength is further stabilized.

Hereinafter, the present invention will be specifically described with reference to the drawings illustrating embodiments thereof.
FIG. 1 is an exploded perspective view showing an example of a battery pack before welding. The battery pack includes a first case half 12 having a square bottom and a side wall formed at the outer edge of the bottom, and a second case half 14 having a square bottom and a side wall formed at the outer edge of the bottom. The battery 10 is housed in a case (a first case half 12 and a second case half 14) having a rectangular parallelepiped battery 10 and having the end portions of the side walls welded together. The first case half 12 and the second case half 14 are made of synthetic resin, and for example, polycarbonate and / or ABS (Acrylonitrile Butadiene Styrene) are used.

  FIG. 2A is a cross-sectional view taken along line AA of FIG. 1 showing an example of welding of the first case half 12 and the second case half 14 according to the present invention. However, the battery 10 is omitted. On the inner edge side of the front end of the side wall of the first case half 12, a protruding welding rib 30 is formed. Further, a welding surface 18 on which the welding rib 30 is welded is formed on the inner edge side of the end portion of the side wall of the second case half body 14, and a plate-like protrusion is formed on the outer edge side. The welding ribs 30 are formed on the entire circumference of the side wall of the first case half 12 or are formed at predetermined intervals.

  FIG. 2B is an enlarged cross-sectional view of the weld rib 30 and the welded surface 18 portion of FIG. However, the battery 10 is omitted. A plurality of protrusions are provided in the thickness direction at the tip of the welding rib 30. In the example of FIG. 2A, two protrusions having a V-shaped cross section (hereinafter referred to as a vertical cross section) in a direction orthogonal to the circumferential direction of the first case half 12 are provided at the tip of the welding rib 30. ing. Further, there is almost no space between the two protrusions, and the longitudinal section between the protrusions is an inverted V shape.

  Here, the thickness a of the bottom of the first case half 12 is 0.3 mm, and the thickness b of the bottom of the second case half 14 is 0.3 mm. The thickness c of the welding rib 30 is 0.4 mm, and the height d of the protrusion provided at the tip of the welding rib 30 is 0.35 mm. Further, the width f of the plate-like protrusion formed on the outer edge side of the side wall tip of the second case half 14 is 0.35 mm, the height g is 0.4 mm, and the width e of the welding surface is 0.45 mm. And the thickness (e + f) of the side wall is 0.8 mm. However, the values a to f are not limited to the above values. For example, the thicknesses a and b of the bottom are set to arbitrary values of 0.25 to 0.5 mm, and the thickness c of the welding rib is set to 0.3. It can be set to an arbitrary value of ~ 0.5 mm, the height d of the protrusion can be set to an arbitrary value of 0.3 to 0.4 mm, the width e of the welding surface can be set to 0.35 to 0.55 mm, and the plate shape The width f of the protrusion is 0.2 to 0.5 mm, the thickness (e + f) of the side wall is an arbitrary value of 0.7 to 0.9 mm, and the height g of the plate-like protrusion is 0.3 to 0. It is possible to set it to an arbitrary value of 6 mm.

  Next, ultrasonic welding between the welding rib 30 and the welding surface 18 will be described. As shown in FIG. 1, the battery 10 is housed in a second case half 14 with the bottom facing downward, covered with the first case half 12 with the bottom facing upward, and the side wall tip of the second case half 14. The welding rib 30 at the front end of the side wall of the first case half 12 is brought into contact with the welding surface 18 of the part. Then, by placing the ultrasonic horn at a required position of the first case half 12 and applying a required high frequency, vibration is applied to the first case half 12 and the welding rib 30 and the welding surface 18 vibrate. The welding rib 30 is melted by being heated by the frictional heat generated by. When the application of the high frequency is finished, the temperature of the melted portion gradually decreases, and the welding rib 30 of the first case half 12 and the welding surface 18 of the second case half 14 are welded and integrated.

  In the process of welding, the welding rib 30 has two protrusions, so that the pressure applied from the ultrasonic horn is distributed to each of the two protrusions, so that the welding rib 30 is unlikely to fall down and hardly fall off the welding surface 18. . Therefore, the welding strength is stable, and the conventional drop-off preventing rib is not necessary. By eliminating the drop-off prevention rib, the thickness of the side wall of the case can be reduced.

  In the above-described embodiment, two protrusions are provided at the tip of the welding rib 30, but three or more protrusions may be provided. FIG. 3A is an enlarged cross-sectional view of the main part showing an example of the welding rib 32 provided with three protrusions at the tip. However, the battery 10 is omitted. The tip of the welding rib 32 is provided with three protrusions in the thickness direction, and it is easier to balance than the case where two protrusions are provided, and it is more difficult to fall down during ultrasonic welding.

  Further, the vertical cross section of the protrusion provided on the welding rib is not limited to the V shape, and may be trapezoidal. FIG. 3B is an enlarged cross-sectional view of a main part showing an example of a welding rib 34 in which a protrusion having a trapezoidal longitudinal section is provided at the tip. However, the battery 10 is omitted. When the vertical cross section of the protrusion is trapezoidal, the contact area with the welding surface 18 is increased as compared with the case of the V shape, so that it is easy to balance and the tip is not easily deformed. Therefore, stable welding can be performed.

  Further, the longitudinal section between the plurality of protrusions of the welding rib is not limited to the V shape, and it is possible to provide a concave portion having a circular or trapezoidal longitudinal section. 4A and 4B are main part enlarged sectional views showing examples of the welding ribs 36 and 38 in which concave portions having a circular or trapezoidal longitudinal section are provided between the plurality of protrusions of the welding rib. It is. However, the battery 10 is omitted. When a concave portion having a circular or trapezoidal longitudinal cross section is provided between the plurality of protrusions, stress is not concentrated on one point as compared with the case of a V-shape, so that the protrusions are hardly torn during welding. Since it is difficult to tear between the protrusions, stable welding can be performed.

  It is also possible to combine the embodiments described above. For example, as shown in FIG. 3B, the longitudinal section of the plurality of protrusions provided on the welding rib is trapezoidal, and the longitudinal section is circular between the plurality of protrusions as shown in FIG. It is possible to provide a shaped recess.

It is a disassembled perspective view which shows the example of the battery pack before welding. (A) is the AA line cutting | disconnection principal part sectional drawing of FIG. 1 which shows the example of welding of the 1st case half body and 2nd case half body which concern on this invention, (b) is (a). It is an expanded sectional view of a welding rib and a welding surface part. (A) is a principal part expanded sectional view which shows the example of the welding rib provided with three processus | protrusions, (b) is a principal part expanded cross section in which the longitudinal cross-section of the said processus | protrusion shows the example of a trapezoid shape. FIG. It is a principal part expanded sectional view which shows the example of the welding rib in which the longitudinal cross-section provided the circular shape or the trapezoid-shaped recessed part between the some protrusion provided in the welding rib. It is an AA line cutting important section sectional view of Drawing 1 showing the conventional example of welding of the 1st case half and the 2nd case half. It is an AA line cutting important section sectional view of Drawing 1 showing the conventional example of welding of the 1st case half and the 2nd case half.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Battery 12 1st case half 14 Second case half 18 Welding surface 20 Ultrasonic horn 30, 32, 34, 36, 38 Welding rib

Claims (5)

A first case half having a bottom and a side wall, wherein a protruding welding rib is formed at the tip of the side wall, and a welding having a bottom and a side wall, wherein the welding rib is welded to the tip of the side wall In a battery pack comprising a second case half formed with a surface, a battery accommodated in the first case half and the second case half welded to the welding rib and the welding surface,
The battery pack according to claim 1, wherein a tip end portion of the welding rib has a plurality of protrusions in a thickness direction.   The battery pack according to claim 1, wherein a tip end portion of the welding rib has three or more protrusions in a thickness direction.   The battery pack according to claim 1 or 2, wherein a cross section of the plurality of protrusions in a direction orthogonal to a circumferential direction of the first case half is trapezoidal.   4. A recess having a semicircular or trapezoidal cross section in a direction perpendicular to the circumferential direction of the first case half is provided between the plurality of protrusions. Battery pack. A first case half having a bottom and a side wall, wherein a protruding welding rib is formed at the tip of the side wall, and a welding having a bottom and a side wall, wherein the welding rib is welded to the tip of the side wall In a method of manufacturing a battery pack, comprising: a second case half formed with a surface; a battery accommodated in the first case half and the second case half welded to the weld rib and the weld surface;
A method for manufacturing a battery pack, comprising: using a first case half provided with a plurality of protrusions in a thickness direction of a tip portion of the welding rib.

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