JP2002324523A - Method for sealing opening of sealed cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for sealing the opening of a cell casing, which controls variations in the sealing and prevents cutting of an insulation resin gasket due to over-pressing by uniformly pressing and caulking around the brim of the opening. SOLUTION: In the cylindrical cell casing 1 with a bottom, shaped in an oblong circle cross-section with semicircular shorter sides and straight longer sides, there is encased electricity generating elements 5. On a supporting loop portion 9 inwardly projected by forming a loop groove 6 on the outer periphery of the casing upper part, there is supported a plate 4 to close the opening with the insulation resin gasket 2 therebetween. The gasket 2 is then press-deformed by caulking the opening 1a having the straight longer sides B and the semiconductor shorter sides A using a metal mold 8 to close the opening in R-shape with the arc angle θ larger than 90 deg. on its straight longer sides B and the arc angle θsmaller than that arc angle θ on its semicircular shorter sides A, whereby the opening 1a is closed with the closing plate 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for sealing a sealed battery such as a non-aqueous electrolyte secondary battery, and more particularly to a method for sealing a battery having a substantially elliptical cross section in which a short side is semicircular and a long side is straight. The present invention relates to a method for sealing a battery.

[0002]

2. Description of the Related Art In recent years, portable cordless devices such as AV devices, mobile phones, and notebook personal computers have been rapidly spreading. As these driving power supplies, non-aqueous electrolyte secondary batteries represented by high-capacity alkaline storage batteries and lithium secondary batteries are suitable, and these non-aqueous electrolyte secondary batteries are further reduced in size and increased in capacity. It is desired to make it.

The structure of a conventional sealed battery will be described with reference to FIG. In FIG. 1, 1 is a battery case also serving as a terminal plate, 2 is an insulating resin gasket having a substantially L-shaped cross section, 3 is a metal reinforcing plate for preventing deformation such as dents and swelling of the battery case 1, and 4 is a built-in explosion-proof mechanism. The assembled sealing plates 5 are power generating elements housed in the battery case 1.

[0004] Next, a sealing method of this sealed battery is shown in FIG.
Description will be made with reference to (a) and (b). After the power generation element 5 is stored in the battery case 1, the metal reinforcing plate 3 is arranged at a predetermined position from the opening end 1a of the battery case 1 and fixed by laser welding or the like. Next, the battery case 1 is gradually drawn inward on the outer peripheral surface on the side of the opening end 1a from the place where the metal reinforcing plate 3 is fixed by using a drawing die having a predetermined shape to form an annular groove 6. After applying a sealing agent such as bron asphalt to the inner peripheral surface of the battery case 1 extending from the annular groove 6 to the opening end 1a, the insulating member 9 is insulated to the annular support portion 9 bulged inward by forming the annular groove 6. The assembled sealing plate 4 is supported via the resin gasket 2. Next, as shown in FIG. 4 (b), the opening end 1a of the battery case 1 is caulked with the upper sealing die 8 while the annular groove 6 is held by the lower sealing die 7, so that the insulating resin gasket 2 is formed. Is compressed and deformed, and the opening end 1a is sealed by the assembly sealing plate 4.

The battery case 1 of this sealed battery is shown in FIG.
As shown in the figure, it is a bottomed cylindrical shape having a substantially elliptical cross section having a semicircular short side and a linear long side, and thus a semicircular short side A and a straight line As shown in FIG. 6A, the conventional method of caulking and closing the opening end 1a of a battery case having a long side B in a circular shape has an arc angle θ of 90 ° (1 °).
A method of flattening and crimping the upper surface of the open end 1a of the battery case 1 using an R-shaped sealing upper die 8 of (/ 4 arc) and an arc angle θ of 90 ° as shown in FIG. There is a method in which the upper surface of the opening end 1a of the battery case 1 is rounded and caulked using a larger (1/4 arc or more) round upper sealing die 8.

[0006]

However, in the above-mentioned conventional sealing method, the arc angle θ shown in FIG.
Using a round upper sealing die 8 of 90 °
In the method of flattening and crimping the upper surface of a, the following problem occurs. In particular, FIG. 7 shows the closed state of the linear long side B of the battery case 1 having a flat side surface.
As shown in FIG. 7A, at the moment when the battery is present in the mold (upper mold) 8 at the time of sealing, the open end 1a of the battery case 1 is formed along the mold. As shown in (2), at the moment the battery comes out of the mold after the sealing is completed, buckling occurs and the insulating resin gasket 2 cannot be sufficiently compressed, and the closed state of the opening end 1a by the assembled sealing plate 4 cannot be secured. Problems arise. This phenomenon appears more remarkably as the thickness of the battery case 1 increases.

The arc angle θ shown in FIG.
Opening end 1a using a larger rounded upper sealing die 8
In the method of rounding and caulking the upper surface of the device, the following problem occurs. That is, at the short side A of the semicircular shape of the battery case 1 having the curved side surface, as shown in FIG. 8A showing the closed state, the battery case 1 is swaged along the mold,
As shown in FIG. 8 (b), the long side portion B having a flat side surface shape is crimped in a state of being bent at the tip. For this reason, there is a local difference in the sealing shape, and FIG.
As shown in the figure, a long side B in a straight line and a short side A in a semicircular shape
At the joining point C, the insulating resin gasket 2 is excessively compressed by winding the opening end 1a and the insulating resin gasket 2 is cut.

Therefore, the present invention solves such a problem,
An object of the present invention is to provide a method of sealing a sealed battery in which the entire circumference of an open end of a battery case is uniformly compressed and caulked, thereby preventing variations in a sealing state and disconnection due to excessive compression of an insulating resin gasket. .

[0009]

In order to achieve the above object, a method for sealing a sealed battery according to the present invention comprises an approximately elliptical cross section having a semicircular short side and a linear long side. After accommodating the power generating element in the bottomed cylindrical battery case having a shape, an insulating resin gasket is provided on the annular support portion which is bulged inward by forming an annular groove in the upper outer peripheral surface of the battery case. In addition to supporting the sealing plate through the arc, the arc angle is greater than 90 ° in the straight long side portion, and the arc angle in the short side portion of the semicircular shape is larger than the arc angle in the long side portion. Using a small rounded sealing mold, the insulating resin gasket is compressed and deformed by caulking the open end of the long side or the short side, and the open end is sealed by the sealing plate. .

According to this method for sealing a sealed battery, a sealing mold having a round shape having a long side in a cross-sectional shape and a round shape having an arc angle larger than 90 ° at a long side in a plane is used, In the short side of the curved surface, which forms the short side of the surface shape, by using a sealing mold having a round shape smaller than the arc angle of the long side, an appropriate sealing corresponding to the side shape of the battery case. It can be carried out. Therefore, as in the conventional sealing method, the problem of insufficient compression due to buckling at the long side of the battery case can be improved,
In addition to reducing the variation in the sealing state at the open end of the battery case, there is no local difference in the sealing shape at the junction between the long side and the short side, and excessive compression molding of the insulating resin gasket is prevented. Since it is not performed, local excessive compression on the insulating resin gasket can be improved to prevent the local resin from being cut, and a stable and appropriate sealing can be reliably performed.

In the above invention, it is preferable that the sealing mold has a round shape in which the arc angle at the long side is larger than 90 ° and the round shape in which the arc angle at the short side is approximately 90 °.

In the above invention, the short side portion of the battery case is swaged by using an R-shaped sealing mold having a larger radius of curvature than the long side portion of the battery case. It can be further reduced.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a method for sealing a sealed battery according to the present invention will be described below with reference to FIGS. . Since the structure of the sealed battery is substantially the same as that described in the conventional example, the description is referred to.
The sealed battery used in this example has a length of 30 m.
m, a width of 6 mm, and a height of 48 mm.

(Embodiment) In FIG. 1, reference numeral 1 denotes a battery case also serving as a terminal plate, 2 denotes an insulating resin gasket having a substantially L-shaped cross section, and 3 denotes a metal reinforcing plate for preventing the battery case 1 from being deformed such as dents or bulges. Reference numeral 4 denotes an assembled sealing plate in which an explosion-proof mechanism is incorporated, and reference numeral 5 denotes a power generation element housed in the battery case 1.

Next, a method of sealing the sealed battery will be described with reference to FIGS. 4A and 4B showing a conventional example. After the power generation element 5 is stored in the battery case 1, the metal reinforcing plate 3 is arranged at a predetermined position from the opening end 1a of the battery case 1 and fixed by laser welding or the like. Next, the battery case 1 is gradually drawn inward on the outer peripheral surface on the side of the opening end 1a from the place where the metal reinforcing plate 3 is fixed by using a drawing die having a predetermined shape to form an annular groove 6. Open end 1a from the annular groove 6
A sealing agent such as bron asphalt is applied to the inner peripheral surface of the battery case 1, and the annular support portion 9 swelled inward by the formation of the annular groove 6 is assembled and sealed via the insulating resin gasket 2. The plate 4 is supported. At this time, the thickness of the battery case 1 was 0.22 mm, the thickness of the metal reinforcing plate 3 was 1.0 mm,
The side thickness of the insulating resin gasket 2 is 0.35 mm, and the bottom thickness is 0.45 mm.

Next, as shown in FIG. 4B, while the annular groove 6 is held by the lower sealing die 7, the open end 1 a of the battery case 1 is caulked using the upper sealing die 8 to provide insulation. The resin gasket 2 is compressed and deformed, and the opening end 1 a is sealed by the assembly sealing plate 4.

The battery case 1 of this sealed battery is shown in FIG.
As shown in the figure, the opening end 1a of the battery case having a bottomed cylindrical shape having the semicircular short side portion A and the linear long side portion B, and having such an oblong cross section. In the present embodiment, the following method is adopted as a method of closing and closing. still,
The arc angle θ of the round shape of the upper sealing die 8 and the shape thereof are the same as those in FIGS. 6A and 6B shown in the conventional example.

In this embodiment, as shown in FIG. 4A, a semicircular short side A has a radius R of curvature of 0.8 mm and an arc angle θ of 90 ° (1/4 arc). Using a method in which the upper surface of the opening end 1a is flattened and crushed by using the upper sealing die 8, as shown in FIG. 4 (b), the linear long side B has a radius of curvature R of 0.8 mm and a circular arc. Angle θ is 100 °
Then, a method is employed in which the upper surface of the opening end 1a is rounded and caulked by using a radius of a 1/4 or more arc having a protrusion amount of 0.3 mm.

When the opening end 1a of the battery case 1 is swaged to a predetermined state using a mold having the above-described shape (the upper sealing die 8), the compression amount of the opening end 1a is 50 to 60 over the entire circumference.
%, And it becomes possible to uniformly seal within the range of 10%. By the way, when the same battery is sealed by the conventional method, the mold having a 1/4 arc around the circumference shown in FIG.
The compression amount becomes about 60%, and the whole circumference 1/1 shown in FIG.
In the case of a mold having four or more arcs, the compression amount is 50 to 80%, and each compressed state has a variation of about 30%.

In the above embodiment, the short side A of the semicircular shape is used.
In the above example, the radius R of curvature of the linear long side B is the same as that of the linear long side B. However, the semicircular short side A is larger than the linear long side B for the purpose of reducing entrainment. A greater effect can be obtained by sealing with a round shape having a radius of curvature.

[0021]

According to the method for sealing a sealed battery of the present invention, in a battery having an oval cross section in which the compression state of the insulating resin gasket of the sealing plate is likely to vary, as described above, the half of the battery case is formed. By providing a difference in the sealing shape corresponding to the side shape of each of the circular short side and the linear long side, the problem of insufficient compression due to buckling of the battery case is improved and the opening of the battery case is improved. It is possible to reduce the variation in the state of sealing of the end, to prevent local overcompression of the insulating resin gasket and to prevent it from being cut off, and to reliably perform stable and appropriate sealing.

[Brief description of the drawings]

FIG. 1 is a vertical sectional side view of a sealed battery.

FIG. 2 is a cross-sectional plan view schematically showing a battery case used in the embodiment of the present invention.

FIGS. 3A and 3B show a sealing method in the same embodiment together with a mold (upper mold); FIG. 3A is a cross-sectional view showing a method of sealing a short side of a battery case; FIG. Sectional drawing which shows the sealing method.

FIGS. 4A and 4B are cross-sectional views showing a conventional sealing method in order of FIGS.

FIG. 5 is a cross-sectional plan view schematically showing a battery case used in a conventional example.

6A and 6B show a round shape of a mold (upper sealing mold) used in a conventional example, where FIG. 6A is a schematic view of a mold having an arc angle of 90 °, and FIG.
Is a schematic view of a mold having an arc angle larger than 90 °.

7A and 7B show a state of sealing a portion B of a battery case using the mold of FIG. 6A in a conventional example, and FIG.
(B) shows the state after the sealing is completed.

8 (a) to 8 (c) are schematic views showing the sealed state of each part of the battery cases A to C using the mold of FIG. 6 (b) in the conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Battery case 1a Open end 2 Insulating resin gasket 4 Assembly sealing plate (sealing plate) 5 Power generation element 6 Annular groove 7 Lower sealing mold (sealing mold) 8 Upper sealing mold (sealing mold) 9 Annular support A semi-circular shape The short side of B The long side of the straight line

 ──────────────────────────────────────────────────続 き Continued from the front page (72) Inventor Hiroki Inoue 1006 Kazuma Kadoma, Kadoma City, Osaka Prefecture F-term (reference) 5H011 AA09 AA17 CC06 DD15 DD26 FF03 GG02 HH02 KK03 5H029 AJ11 AJ14 AJ15 BJ02 CJ03 CJ28 CJ30 DJ02 DJ03 DJ12 EJ01 EJ12 HJ00 HJ12

Claims (3)

[Claims] 1. A power generating element is housed in a bottomed cylindrical battery case having a substantially elliptical cross section including a semicircular short side portion and a linear long side portion, and then an upper portion of the battery case is provided. An annular groove is formed on the outer peripheral surface to support the sealing plate via an insulating resin gasket on the annular support portion bulged inward, and the linear long side portion has an arc angle of 90 °.
The opening end of the long side or the short side is formed by using a sealing die having a round shape larger than ° and an arc angle at the short side portion of the semicircular shape smaller than the arc angle at the long side portion. By compressing and deforming the insulating resin gasket, and sealing the opening end with the sealing plate. 2. The sealing die according to claim 1, wherein the arc shape has an arc angle greater than 90 ° at a long side of the straight line, and the arc shape has an arc angle of approximately 90 ° at a short side of the semicircle. The method for sealing a sealed battery according to the above. 3. The semicircular short side portion of the battery case is swaged using a round die having a radius of curvature larger than that of the linear long side portion of the battery case. Sealing method for sealed batteries.