JP3129668B2 - Welding part structure of outer case of electric double layer capacitor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a structure for welded section of external container of capacitor which can eliminate the need of any deburring process by forming a pool for burrs protruded from the friction welding joint surface between the main body and lid body of the external container of a capacitor without increasing the external size of the main body of the enclosure. SOLUTION: The quantity of burrs of a molten resin protruded from a joint surface is suppressed by reducing the occurring quantity of the molten resin itself as much as possible by forming the end face 26 of the front end section 24 of the main body 22 of a resin-made external container in an inclined surface 26 tapered within the range of a welding margin. When the end face 26 is formed in the inclined surface 26, a pool having a sufficiently large volume can be formed without making the main body 22 of the container unnecessarily thicker by reducing the volume of a recessed section 28 as pool for burrs formed along the outer peripheral edge of the front end section 24.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an outer casing of an electric double layer capacitor, and more particularly to an electric double layer capacitor in which an opening of a resin outer casing body and a lid are welded and integrated by frictional heat. The present invention relates to improvement of a welded part structure of an outer container.

[0002]

2. Description of the Related Art In general, an outer container of an electric double layer capacitor is often made of a resin having a bottomed outer container body and a lid. 3 (a) to 3 (e) show the resin-made outer container body and the lid body which are conventionally used, and FIG. 3 (a) is a plan view of the opening side of the outer container body 4, 4B is a front view thereof, FIG. 4C is an enlarged sectional view of a portion A shown in FIG. 4B, and FIGS. 4D and 4E are resin cover 6 described above. (D) is a plan view, and (e) is a front view.

As shown in FIGS. 3 (a) to 3 (c), the outer container body 4 is formed in a bottomed cylindrical shape having an almost rectangular parallelepiped appearance and an open top, and has a wall thickness of 2.5 mm. It is formed in a uniform degree. In addition, the end portion 4a of the annular main body 4 of the outer container main body 4 which defines the substantially rectangular opening 8 is formed as a flat flat surface.

On the other hand, as shown in FIGS. 3 (d) and 3 (e), the lid 6 has a plate-like portion having an outer shape coinciding with an outer peripheral edge of a front end defining an opening 8 of the outer container body 4. 6a, and two metal terminal rods 10 penetrating through the plate-shaped portion 6a. The terminal rod 10 has an outer peripheral edge extending vertically along the outer peripheral edge thereof for holding a terminal rod having a circular cross section. The boss portion 6b is integrally formed by extending from the plate portion, and is integrated by inserting the terminal rod 10 into a molding die and performing injection molding.

[0005] The outer container body 4 and the lid 6 are usually integrally joined by welding. This is because when an adhesive is used, the adhesive is easily deteriorated with time due to the electrolyte solution sealed therein, and it is difficult to ensure durability. The welding method includes a high-frequency welding method in which ultrasonic bonding is applied in a vertical direction while the outer container body 4 and the lid 6 are pressed against each other to heat and weld the joint surface. Body 6
The low frequency welding method of welding by frictional heat by pressing while making a circular motion with a radius of about 0.5 mm in a low frequency cycle of several hundred Hz, but damages the contents of the outer container and the terminal rod Therefore, a low-frequency welding method is often employed. In this case, the welding margin for melting is set to about 0.3 mm as shown in FIG.

[0006]

By the way, FIG. 4 (a)
(D) shows the welding step by the low frequency welding method in order, but according to the low frequency welding method, the frictional welding involves a step from the joining surface between the end face 4a of the front end of the main body and the lid 6. It is difficult to prevent the molten resin from protruding, and the molten resin becomes burrs 12 and protrudes along the joint surface (see FIG. (C)). If such burrs 12 are left protruding, the external dimensions of the electric double-layer capacitor as components are increased. The burr 12 is scraped by a grinder 14 in a later step.

However, in the deburring by the grinder 14, it is difficult to scrape off only the burr 12, and it is easy to damage even the outer container body 4 and the lid 6, thereby only deteriorating the appearance. However, there is a problem that the strength of the joint may be reduced.

Therefore, in order to eliminate the need for this deburring operation, as shown in FIG.
May be provided in a groove shape. However, in order to secure the sealing performance between the outer container 4 and the lid 6 and the pressure resistance against the increase in the internal pressure of the outer container 2, the thickness of the joint surface of the outer container body cannot be made too thin. , At least about 2.0 mm is required. Also, since the melting margin of about 0.3 mm is required in the crimping direction,
An unexpectedly large amount of molten resin protrudes from the joint surface.

Therefore, if the groove-shaped burr pool 16 is provided with a sufficient volume so that the molten resin does not protrude to the outer side surface, and the width in the height direction is about 1.0 mm, the container of the burr pool 16 is provided. The depth in the body thickness direction is also 1.
A thickness of about 0 mm is required, and as a result, the thickness of the container body 4 below the burr pool 16 to be formed must be as thick as about 3.0 mm.

However, the formation of the flash pool 16 in this manner results in the outer container body 4 being formed much thicker than necessary as a whole, which not only leads to an increase in external dimensions, but also increases the external dimensions. There is a possibility that the cost of the resin material increases and the cost increases, and that there is a possibility that the resin molding may be hindered.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to minimize the amount of molten resin protruding from between bonding surfaces and forming burrs, An outer container welding portion of an electric double layer capacitor capable of forming a burr pool having a sufficient capacity for accommodating burrs protruding from the joint surface without increasing the outer dimensions of the container body, thereby eliminating the deburring process. It is to provide a structure.

[0012]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides an annular main body end portion 24 defining an opening 8 of a resin outer container body 22 and a lower portion for sealing the opening 8.
In the outer container welding portion structure of the electric double layer capacitor in which the lid 6 having a flat surface is welded by friction heat to be integrated, the main body front end portion 24 is formed in a tapered shape in which the inner peripheral side of the end surface 26 protrudes. Along with the outer peripheral edge of the main body front end portion 24, a joining surface between the main body front end portion 24 and the lid body 6.
With the circular motion of the cycle in the low frequency region in the horizontal direction.
At the time of friction welding in which welding is performed by generating frictional heat,
A concave portion 28 is formed for storing the molten resin protruding from between the joining surfaces of the cover 6 and the cover 6.

By forming the tip of the main body in a tapered shape within the range of the welding margin, the amount of generated molten resin itself is reduced as much as possible, and the amount of flash of the molten resin protruding from the joint surface is suppressed. . Thereby, the volume of the concave portion formed as a burr pool along the outer peripheral edge of the main body front end portion can be reduced,
It is possible to form a burr pool having a sufficient volume without increasing the thickness of the container body more than necessary. Therefore, a deburring operation in a later step may be unnecessary.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, an embodiment of an outer container welding portion structure of an electric double layer capacitor according to the present invention will be described.
This will be described in detail with reference to FIGS.

FIG. 1 shows an outer container body made of a resin having a welded portion structure according to the present invention. FIG. 1 (a) is a plan view showing an opening side, FIG. 1 (b) is a front view, and FIG. (C) is the previous figure (b)
It is an expanded sectional view of the A section shown in the inside. 2A and 2B show a completed electric double-layer capacitor after the lid is welded. FIG. 2A is a front view, and FIG. 2B is an enlarged sectional view of a portion A in FIG. .

As shown in FIGS. 1 (a) to 1 (c), the outer container body 22 is formed in a rectangular bottomed cylindrical shape, and its overall basic shape is the same as the conventional example described in FIG. And the wall thickness is the same as 2.5 mm.

FIG. 2 shows the outer container body 22.
As shown in the figure, the lid 6 exactly the same as the conventional example is also friction-welded with a welding margin of 0.3 mm by the low frequency welding method and integrally joined, but the structure of the welding portion for joining the lid 6 Is configured as follows.

That is, as shown in FIG. 1C, an annular main body tip 2 defining an opening 8 of the outer container main body 22 is formed.
Reference numeral 4 denotes an end surface 26 serving as a joining surface having a tapered inclined surface 2.
6a, the inclination direction of which is such that the inner peripheral side protrudes upward and the outer peripheral side falls downward substantially by the welding allowance.

The outer peripheral edge of the main body tip 24 is extended along the entire periphery along the entire periphery thereof during friction welding.
A concave portion 28 is formed for storing the molten resin protruding from between the joining surfaces of the cover and the lid 6.

More specifically, in this embodiment, FIG.
As shown in (c), the depth of the concave portion 28 in the thickness direction is 0.5 mm, and the thickness of the main body distal end portion 24 in the portion where the concave portion 28 is formed is 2.0 mm. . The end surface 26 to be welded and joined has a flat surface 26b having a width of 0.3 mm on its inner peripheral edge, and the outer surface thereof has a tapered width of 1.
It is formed on the inclined surface 26a over 7 mm. Here, the inclined surface 26a has a welding allowance of 0.3 mm as described above.
The outer peripheral edge side is inclined downward by a distance, and the degree of inclination is 0.3 / 1.7.

As shown in FIG. 2B, the height of the recess 28 after welding of the lid 6 is 1.0 mm.

Therefore, in the welded portion structure thus configured, the amount of the molten resin generated itself can be reduced as much as possible by forming the end face of the main body distal end portion 24 into a tapered shape within the range of the welding allowance. Accordingly, the amount of burrs of the molten resin protruding from the joint surface can be suppressed.

As a result, the volume of the concave portion 28 formed as a burr pool along the outer peripheral edge of the main body front end portion 24 can be reduced, so that the container main body 22 can have a sufficient volume without increasing the wall thickness more than necessary. It becomes possible to form burrs. Therefore, it is possible to eliminate the need for a deburring operation in a later step. For this reason, the appearance of the electric double layer capacitor is not impaired, and there is no possibility that the strength of the joint portion of the outer container is reduced.

Further, since the end face 26 is formed in a tapered shape, the contact area immediately after the start of the friction welding is small, so that the driving force for the friction welding can be reduced as much as possible.

[0025]

As described in detail in the above embodiments, according to the outer container welding portion structure of the electric double layer capacitor according to the present invention, the shape of the end surface of the front end portion of the main body of the resin container is set within the range of the welding allowance. It is formed in a tapered shape and the tip of this body
Low in the horizontal direction relative to the joint surface with the lid with a flat bottom
Welding by generating frictional heat by the circular motion of the frequency domain cycle
By doing so, the amount of generated molten resin itself can be reduced as much as possible, and the amount of burrs of the molten resin protruding from the joint surface can be suppressed. The volume can be reduced, and a burr pool having a sufficient volume can be formed without increasing the thickness of the container body more than necessary. Therefore, the deburring work in the post-process can be made unnecessary, and there is no danger that the appearance is impaired or the strength of the welded joint is reduced.

[Brief description of the drawings]

1A and 1B show a resin outer container main body provided with a welded portion structure of the present invention, wherein FIG. 1A is a plan view of an opening side of the outer container main body, and FIG. 1B is a front view thereof. FIG. 2C is an enlarged sectional view of a portion c shown in FIG. 1B.

FIGS. 2A and 2B show a completed electric double-layer capacitor after lid welding, in which FIG. 2A is a front view, and FIG. 2B is an enlarged sectional view of a portion A in FIG.

3A and 3B show a conventional resin exterior container body and a lid body, wherein FIG. 3A is a plan view of the opening side of the exterior container body, FIG. 3B is a front view of the container body, FIG. 1C is an enlarged sectional view of a portion c shown in FIG. 1B, FIG. 2D is a plan view of a lid commonly used in the present invention, and FIG.
Is a front view of the lid.

FIG. 4 is an explanatory view showing a welding step by a low frequency welding method in order.

FIGS. 5A and 5B show a conventional outer container having a burr pool formed therein, wherein FIG. 5A is a front view and FIG. 5B is an enlarged sectional view of a portion D in FIG.

[Explanation of symbols]

 8 Opening 22 Outer container main body 24 Main body tip 26 End face 28 Recess

Continuation of the front page (56) References JP-A-2-266508 (JP, A) JP-A 55-108732 (JP, U) JP-A 3-74930 (JP, U) JP-A 5-66955 (JP) , U) (58) Field surveyed (Int.Cl. ⁷ , DB name) H01G 9/155 H01G 9/10

Claims (1)

(57) [Claims] An annular main body tip portion defining an opening portion of a resin outer container main body and a lower portion for sealing the opening portion.
In the outer container welding portion structure of the electric double layer capacitor in which the lid 6 having a flat surface is welded by friction heat to be integrated, the main body front end portion 24 is formed in a tapered shape in which the inner peripheral side of the end surface 26 protrudes. Along with the outer peripheral edge of the main body front end portion 24, a joining surface between the main body front end portion 24 and the lid body 6.
With the circular motion of the cycle in the low frequency region in the horizontal direction.
At the time of friction welding in which welding is performed by generating frictional heat,
A welded portion structure for an electric double layer capacitor, wherein a concave portion 28 is formed for storing a molten resin protruding from a joint surface between the cover and the lid 6.