JPH11219688A - Armoring vessel for quadrangular electrochemical element and manufacture of element using armoring vessel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a lid from dropping into an armoring vessel and enhance the producibility at manufacturing a lithium ion secondary battery of quadrangular form. SOLUTION: Projections 2c are formed facing inward at the four inside corners of an opening in a quadrangular armoring vessel 2, and a bunch of windings 5 is inserted into the vessel 2 and an electrolytic solution is poured in. A lid 3 is placed on the projections 2c, fitted tight, and fastened to the vessel 2 by laser welding sealedly. Thereby the lid 3 fitted to the vessel 2 is supported certainly by the four projections 2c, to prevent the lid 3 from dropping into the vessel 2. As the projections 2c do not hinder insertion of the bunch of windings 5, its 5 insertion into the vessel 2 can be performed smoothly, and becuase the laser welding spot is positioned at the open end of the vessel 2, it is possible to avoid complication of laser welding device. Also good economy is ensured owing to low-cost form preparing operations for the projections 2c.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an outer container used for a square electrochemical element such as a square lithium ion secondary battery or a square electric double layer capacitor, and a method for manufacturing a square electrochemical element using the outer container. Things.

[0002]

2. Description of the Related Art FIG. 4 is a perspective view showing an example of an outer container and a lid of a conventional rectangular lithium ion secondary battery, and FIG. 5 is another example of an outer container and a lid of a conventional rectangular lithium ion secondary battery. FIG. 6 is a perspective view showing another example of the outer container and the lid of the conventional prismatic lithium ion secondary battery.

Conventionally, when a prismatic lithium ion secondary battery 1 is manufactured, as shown in FIG. 4, a winding group (not shown) is inserted into a prismatic outer container 2 and an electrolytic solution is injected. Then, the lid 3 is fitted to the open end of the outer container 2, and the lid 3 is fixed to the outer container 2 by laser welding and sealed. At this time, when the lid 3 is fitted to the outer container 2, the lid 3 is only supported by the fitting tolerance between the two, and there is a possibility that the lid 3 may fall into the outer container 2, Therefore, the productivity of the prismatic lithium ion secondary battery 1 is reduced.

In order to avoid such a situation, it is necessary to take measures to prevent the lid 3 from falling. As shown in FIG. 4, a step 2a is formed at the open end of the outer container 2 over the entire circumference thereof. And a method of fitting the lid 3 on the stepped portion 2a and mounting the lid 3 on the outer container 2 (for example, see Japanese Unexamined Patent Application Publication No.
-293487). As a second method, as shown in FIG. 5, a locking piece 3 a is protruded around the lid 3, and the locking piece 3 a is fitted so as to cover the entire open end of the outer container 2. Alternatively, as a third method, as shown in FIG. 6, four embosses 2b are protruded toward the inside of the outer container 2 by performing embossing near the opening end of the outer container 2, and Place the lid 3 on the outer container 2
It is also conceivable to use a method of fitting it to.

[0005]

However, in the first method, since the outer container 2 having the stepped portion 2a is required, the unit cost is increased and the cost becomes uneconomical.

On the other hand, in the second method, the laser welding point is located all around the side surface of the outer container 2, and the laser beam must be irradiated from the periphery of the outer container 2 while maintaining a uniform focal length. The welding equipment must be complicated.

In the third method, since the four embosses 2b protrude toward the inside of the outer container 2, these embosses 2b become a hindrance factor when inserting the winding group into the outer container 2. .

[0008] Such a situation is not limited to the prismatic lithium ion secondary battery 1 but also applies to other prismatic electrochemical elements (for example, prismatic electric double layer capacitors).

In view of the above circumstances, the present invention not only prevents the lid from falling into the outer container, but is also economical, can avoid the complexity of the laser welding apparatus, and can be wound around the outer container. An object of the present invention is to provide an outer container for a square electrochemical element that allows a group to be inserted smoothly, and a method for manufacturing a square electrochemical element using the outer container.

[0010]

That is, the outer container for a rectangular electrochemical element according to the present invention is a container body having a bottomed rectangular cylindrical shape in the outer container (2) used for the square electrochemical element (1). (2d), and at least two diagonal corners of the opening corners of the container main body have protrusions (2
c) is formed so as to face inward.

The outer container for a square electrochemical element according to the present invention is the outer container (2) used for the square electrochemical element (1), and has a bottomed square cylindrical container body (2d). The projection (2c) is formed at all four corners of the opening of the container body with the inside facing inward.

Here, the material of the outer container (2) is not particularly limited, and for example, an iron-based, aluminum-based, iron-nickel steel plate such as SPCE or SUS can be adopted.

On the other hand, the method for manufacturing a rectangular electrochemical element according to the present invention is applicable to the case where the rectangular electrochemical element (1) is manufactured using the above-described outer container (2) for a rectangular electrochemical element. After the winding group (5) is inserted and the electrolytic solution is injected, a lid (3) is placed and fitted on the projection of the outer container, and the lid is fixed to the outer container by laser welding. It is configured to be sealed.

It should be noted that the numbers in parentheses are for convenience showing the corresponding elements in the drawings, and therefore, the present invention is not limited to the description in the drawings. The same applies to the column of “Claims”.

[0015]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is an exploded perspective view showing an embodiment of a prismatic lithium ion secondary battery using a package for a rectangular electrochemical element according to the present invention. FIG. FIG. 3 is a plan view showing a state in which
It is an expanded sectional view by a line.

As shown in FIG. 1, an outer container 2 for a rectangular electrochemical element according to the present invention has a bottomed square cylindrical container body 2d.
In each of four corners of the opening of the container body 2d, a projection 2c is formed inward. The projections 2c can be formed at a low cost by, for example, a protrusion process or a boss process.

When the prismatic lithium ion secondary battery 1 is manufactured using the outer container 2, the following procedure is performed.

First, a winding group 5 serving as a power generating element is manufactured. To this end, a positive electrode sheet and a negative electrode sheet are laminated with a separator interposed therebetween, which is spirally wound and further crushed into an oval cross section. Then, the winding group 5 having an oval cross section is completed.

Next, the winding group 5 is inserted into the outer container 2. At this time, as shown in FIG.
Since c is formed at the opening corner of the container body 2d,
These projections 2c do not hinder insertion of the winding group 5, and smooth insertion becomes possible. Further, an electrolytic solution is injected into the outer container 2.

Thereafter, as shown in FIG. 3, the lid 3 is placed and fitted on the projection 2c of the outer container 2. Then, since the lid 3 is reliably supported by the four projections 2c, there is no danger that the lid 3 will fall into the exterior container 2.

In this state, the lid 3 is fixed to the outer container 2 by laser welding. At this time, since the laser welding point is located at the opening end of the outer container 2, the laser beam can be irradiated from above the outer container 2 by using a general-purpose laser welding apparatus to perform welding.

When the laser welding is completed in this way, the outer container 2 is sealed with the lid 3, and the prismatic lithium ion secondary battery 1 is completed.

In the above-described embodiment, the case where the protrusions 2c are provided at all four corners of the outer container 2 has been described. However, the protrusions 2c need not necessarily be provided at all the corners of the opening. And at least two diagonals of the outer container 2 (that is, only two diagonals,
2c at the corners of the opening only at all or four)
Is provided, the lid 3 can be reliably supported so as not to fall into the outer container 2.

In the above-described embodiment, the rectangular lithium ion secondary battery 1 has been described. However, the present invention applies to a rectangular electrochemical element (for example, a rectangular electric double layer capacitor) other than the rectangular lithium ion secondary battery 1. It is also possible to apply to.

[0026]

As described above, according to the invention of the outer container for a square electrochemical element of the present invention, the outer container 2 used for the square electrochemical element such as the square lithium ion secondary battery 1 includes: The container body 2d has a bottomed rectangular cylindrical shape, and the protrusion 2c is formed inward at at least two diagonal corners of the opening corners of the container body 2d. When manufacturing a rectangular electrochemical element,
Since the lid 3 can be reliably supported on the outer container 2 by the plurality of protrusions 2 c, in addition to preventing the lid 3 from falling into the outer container 2, the protrusion 2 c prevents the winding group 5 from being inserted. Since it does not hinder, the winding group 5 can be smoothly inserted into the outer container 2. In addition, since the laser welding point is located at the open end of the outer container 2, the laser welding device can be prevented from being complicated, and the operation for forming the projection 2c can be performed at low cost, which is excellent in economical efficiency.

Further, according to the invention of the outer container for a square electrochemical element of the present invention, the outer container 2 used for the square electrochemical element such as the square lithium ion secondary battery 1 has a bottomed square cylindrical shape. A container body 2d;
Since the projections 2c are formed so as to face inward at all four corners of the opening d, the lid 3 is securely placed on the outer container 2 by the four projections 2c when manufacturing the rectangular electrochemical element. The projection 2c does not hinder the insertion of the winding group 5 because the lid 3 can be prevented from falling into the outer container 2 because it can be supported, so that the winding group 5 is smoothly inserted into the outer container 2. It is possible to do. In addition, since the laser welding point is located at the open end of the outer container 2, the laser welding device can be prevented from being complicated, and the operation for forming the projection 2c can be performed at low cost, which is excellent in economical efficiency.

On the other hand, according to the invention of the method for manufacturing a square electrochemical element of the present invention, the square electrochemical element such as the square lithium ion secondary battery 1 is manufactured by using the outer container 2 for the square electrochemical element described above. At the time of manufacturing, after inserting the winding group 5 into the outer container 2 and injecting the electrolytic solution, the lid 3 is placed and fitted on the projection 2 c of the outer container 2, and the lid 3 is Since the lid 3 is fixed to the outer container 2 by welding and sealed, the lid 3 fitted to the outer container 2 is securely supported by the projection 2c. In addition to being able to prevent falling,
Since the projection 2c does not hinder the insertion of the winding group 5, the winding group 5 can be smoothly inserted into the outer container 2.
In addition, since the laser welding point is located at the open end of the outer container 2, the laser welding device can be prevented from being complicated, and the operation for forming the projection 2c can be performed at low cost, which is excellent in economical efficiency.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view showing an embodiment of a prismatic lithium ion secondary battery using an outer container for a prismatic electrochemical device according to the present invention.

FIG. 2 is a plan view showing a state where a winding group is inserted into the outer container shown in FIG.

FIG. 3 is an enlarged sectional view taken along line AA of FIG. 2;

FIG. 4 is a perspective view showing an example of an outer container and a lid of a conventional prismatic lithium ion secondary battery.

FIG. 5 is a perspective view showing another example of an outer container and a lid of a conventional prismatic lithium ion secondary battery.

FIG. 6 is a perspective view showing still another example of an outer container and a lid of a conventional prismatic lithium ion secondary battery.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Square electrochemical element (square lithium ion secondary battery) 2 ... Outer container 2c ... Protrusion 2d ... Container body 3 ... Lid 5 ... Wound group

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Yukiyoshi Oya 5-36-11 Shimbashi, Minato-ku, Tokyo Inside Fuji Electric Chemical Co., Ltd. (72) Yasuhiro Yuasa 250-4 Uda, Tomioka, Gunma 4 Corporation Inside Yuasa Factory

Claims (3)

[Claims] 1. An outer container (2) used for a rectangular electrochemical element (1), comprising a container body (2d) having a bottomed rectangular tube shape, and at least a diagonal corner of an opening corner of the container body. An outer container for a rectangular electrochemical element, wherein projections (2c) are formed at two corners of an opening so as to face inward. 2. An outer container (2) used for a rectangular electrochemical element (1), comprising a bottomed rectangular cylindrical container main body (2d), wherein the container main body has two open corners. Protrusions (2
An outer container for a rectangular electrochemical element, wherein c) is formed facing inward. 3. When a rectangular electrochemical element (1) is manufactured using the outer container (2) for a square electrochemical element according to claim 1 or 2, a winding group ( 5) After inserting the electrolyte and injecting the electrolyte, a lid (3) is placed and fitted on the projection of the outer container, and the lid is fixed to the outer container by laser welding and sealed. A method for producing a rectangular electrochemical element.