KR20010048098A - Prismatic type secondary battery - Google Patents

Abstract

PURPOSE: A square-shaped secondary battery is provided which ensures perfect sealing by improving a sealing process of a cap assembly and reduces defective proportion by decreasing a number of parts. CONSTITUTION: The square-shaped secondary battery comprises: (i) a square-shaped can(4) which receives an electrode group winding an anode, a cathode and a separator; (ii) a cap plate(30) which is welded to the top opening part of the square-shaped can; (iii) holes(32a, 34a) penetrating the cap plate; (iv) electrode taps(32, 34) which are connected to one electrode of the electrode group and are drawn outside by penetrating the holes; (v) an insulating case(36) which covers the electrode tap; (vi) an anode pin(38) which is bonded to the end part of the electrode tap; (vii) an epoxy molding(40) which is coated on the upper side of the cap plate, wherein the other electrode of the electrode group is welded to either the cap plate or the square-shaped can and the anode pin is fixed by the epoxy molding and the holes are sealed by the epoxy molding.

Description

Rectangular type secondary battery {Prismatic type secondary battery}

The present invention relates to a rectangular secondary battery, and more particularly, a rectangular secondary battery which ensures perfect sealing of a cap plate that seals an upper opening of a rectangular secondary battery, and simplifies the process to realize an increase in productivity and a reduction in a defective rate. It relates to a battery.

Secondary batteries are rechargeable batteries, which can be miniaturized and large-capacity, and currently, nickel hydrogen batteries, lithium batteries, and lithium ion batteries are used. The main purpose of the secondary battery is used as a power source for mobile phones, camcorders, notebook computers, etc. The shape is divided into cylindrical and square.

A lithium ion secondary battery uses lithium metal oxide as a positive electrode active material, uses carbon or a carbon composite material as a negative electrode active material, impregnates an electrolyte in which lithium salt is dissolved in an organic solvent, and moves lithium ions between the positive electrode and the negative electrode. Allow discharge to occur.

The structure of a conventionally well-known square lithium ion secondary battery is shown in FIG.

As shown in the drawing, in the structure of a conventional rectangular secondary battery, an electrode group 2 wound around a positive electrode, a negative electrode, and a separator is housed inside a can of the square 4, and the negative electrode and the can 4 are stored in a can ( A negative electrode tab (not shown) drawn from the negative electrode on the inner side of 4) is in contact with the can 4 to be electrically connected. A cap assembly 6 connected to the positive electrode is installed on an upper portion of the can 4, and a liquid electrolyte is injected through an injection hole 8 formed at one side of the cap assembly 6, and then sealed. Lose. The electrode group 2 is insulated from the cap assembly 6 and the can 4 via the insulating plates 10a and 10b on the upper and lower surfaces, respectively.

Looking at the structure of the cap assembly 6 in the upper part of the figure, there is a cap plate 12 which is laser welded to the upper opening of the can 4, the positive plate through the insulator 14 in the center of the cap plate 12 16 is installed and assembled into one body using the rivet 18 penetrating the center of the cap plate 12 and the positive electrode plate 16. The rivet 18 is connected to the positive electrode tab 20 of the electrode group 2 and insulated from the cap plate 12 via the gasket 22. In addition, the break plate 24 is provided in the cap plate 12 as an explosion-proof means for increasing the internal pressure of the battery.

As a method of sealing in the cap assembly 6 of the rectangular secondary battery as described above, methods such as riveting, punching, and coking are used. Riveting is used as illustrated.

However, in the prior art, the number of parts constituting the cap assembly is complicated and the process is complicated. When riveting the parts at once, the parts may be deformed, and the amount of parts in close contact with the shrinkage of the insulator contracted by the riveting. There is a limit in securing a perfect seal by the degree of not constant, and due to the complexity of the process and the difficulty of sealing, there is a problem that the frequency of defective products is very high.

The present invention has been made to solve the above-mentioned conventional problems, to improve the sealing process of the cap assembly to ensure a perfect sealing, and also to reduce the number of parts to simplify the process and increase the production and reduce the defective rate The object is to provide a rectangular secondary battery.

In the present invention devised for this purpose, a rectangular can for accommodating the electrode group wound around the positive electrode, the negative electrode and the separator and a rectangular secondary battery for sealing the upper opening of the rectangular can with a cap plate, the hole formed through the cap plate An electrode tab connected to one electrode of the electrode group and drawn out through the hole, an insulating case surrounding the electrode tab, a positive electrode pin coupled to an end of the electrode tab drawn through the hole; Epoxy molding applied to the upper surface of the cap plate, the other electrode of the electrode group is welded to one of the cap plate and the square can, the positive electrode pin is fixed by epoxy molding, the hole is sealed by epoxy molding Consists of the configuration.

The cap plate has a box shape in which a sidewall of a predetermined height is erected on the rim, and the upper side is opened, and the insulating case is formed of an insulator capable of blocking electrical connection between the conductive cap plate and the electrode tab, and the material is not limited thereto. Nonetheless, polypropylene is preferred.

The positive electrode pin has a hemispherical head and wings are formed at both ends of the body so as to surround the positive electrode tab and the insulating case.

According to the present invention as described above, the process is simplified by reducing the number of parts used in the sealing of the rectangular secondary battery, it is possible to reduce the occurrence of the defective rate significantly because the perfect sealing that can suppress the minute movement by molding with epoxy do.

1 is a cross-sectional view showing a rectangular secondary battery according to the present invention.

Figure 2 is an exploded perspective view of the square secondary battery according to the present invention.

3 is a top view of a rectangular secondary battery according to the present invention.

4 is a cross-sectional view showing a conventionally known square secondary battery.

Explanation of symbols on the main parts of the drawings

2: electrode group 4: can

30: cap plate 32: negative electrode tab

32a: negative electrode tab insertion hole 34: positive electrode tab

34a: positive electrode tab insertion hole 36: insulated case

38: positive electrode pin 38a: positive electrode pin wing portion

40: epoxy

Preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. For reference, in describing the configuration of the present invention, the same reference numerals will be given to the same parts as the drawings described in the related art in order to avoid duplication of description.

1 is a cross-sectional view showing an embodiment of a rectangular secondary battery according to the present invention.

As shown in the drawing, the rectangular secondary battery of the present invention is configured to compress the electrode group 2 formed by winding the positive electrode, the negative electrode, and the separator together, to be housed in the can 4, and to seal the upper opening of the can 4. In this case, the upper opening of the can 4 is weld-sealed with a cap plate 30, and two holes 32a and 34a and an electrolyte injection hole 8 are formed in the cap plate 30, and the hole ( The negative electrode tab 32 and the positive electrode tab 34 drawn from the electrode group 2 are inserted through 32a and 34a, and the negative electrode tab 32 is attached on the surface of the cap plate 30, and the positive electrode tab 34 is formed in the insulating case 36 and connected to the positive electrode pin 38 on the cap plate 30, and is formed by applying epoxy 40 to the upper surface of the cap plate 30 and molding it. .

The schematic configuration described above will be described in more detail with reference to an exploded perspective view of an embodiment according to the present invention shown in FIG. 2.

The cap plate 30 which seals the upper opening of the rectangular can 4 has a box shape in which a vertical side is opened upright around a square, and the upper side is opened, and two holes 32a and 34a are formed at both sides. The electrolyte injection hole 8 is formed at the right end. The left side hole 32a of the two holes 32a and 34a has a negative electrode tab insertion hole 32a through which the negative electrode tab 32 drawn from the negative electrode of the electrode group 2 is inserted and passed through the cap plate 30. The right hole 34a is a positive electrode tab insertion hole 34a through which the positive electrode tab 34 drawn from the positive electrode of the electrode group 2 is inserted and passed through the cap plate 30.

The electrolyte injection hole 8 formed at the right end of the cap plate 30 is an injection hole for injecting a liquid electrolyte before sealing, and the cap plate 30 is welded to the rectangular can 4 to form an inside of the can. Seal it.

The negative electrode tab 32 is inserted into the negative electrode tab insertion hole 32a and then attached to the surface of the cap plate 30, whereby the cap plate 30 is welded to the cap plate 30. Electrically connected to the negative electrode together with (4), the method of attaching the negative electrode tab 32 is not particularly limited, but is preferably by welding.

When the positive electrode tab 34 passes through the positive electrode tab insertion hole 34a, the positive electrode tab 34 is embedded in the insulating case 36 to protrude above the cap plate 30, and the insulating case 36 is a negatively conductive cap plate. A function of preventing a short between the 30 and the positive electrode tab 34 is performed.

The insulating case 36 may be made of a material having the property of an insulator that cuts off electrical connections. In the present invention, polypropylene having excellent heat resistance may be adopted.

The positive electrode tab 34, which is in the polypropylene insulating case 36 and passes through the positive electrode tab insertion hole 34a, is electrically connected to the positive electrode pin 38, and the positive electrode pin 38 is the positive electrode tab 34. ) And the polypropylene insulation case 36 are wrapped at the same time. The positive electrode pin 38 has a hemispherical head 38a, and wings 38b are formed on both sides of the body to surround the positive electrode tab 34 and the polypropylene insulating case 36. The positive electrode pin 38 simultaneously wrapping the positive electrode tab 34 and the polypropylene insulating case 36 is fixed on the cap plate 30.

As described above, after the negative electrode tab 32 is attached and the electrolyte is injected into the electrolyte injection hole 8 formed at the right end of the cap plate 30 on which the positive electrode pin 38 is fixed and weld-sealed, the cap plate ( 30) The epoxy 40 is poured into the mold.

3 is a top view of the rectangular secondary battery of the present invention from above.

As shown in the drawing, the negative electrode tab 32 drawn out from the negative electrode of the electrode group 2 protrudes through the negative electrode tab insertion hole 32a formed on the left side of the cap plate 30, and is attached to the surface of the cap plate 30. On the right side, the polypropylene insulating case 36 and the positive electrode tab 34 embedded therein protrude through the positive electrode tab insertion hole 34a, and the protruding positive electrode tab 34 and the polypropylene insulating case 36 are positive electrodes. The positive electrode pin 38 formed at the same time by the wing portion 38b of the pin 38 is erected. In addition, the electrolyte injection hole 8 for injecting the electrolyte is sealed at the right end after the electrolyte is injected, and the cap plate 30 structure as described above is formed and then molded into the epoxy 40.

In the exemplary embodiment, the positions of the positive electrode tab insertion hole 34a and the negative electrode tab insertion hole 32a may be changed depending on the purpose of implementation, and the positive electrode pin 38 may serve as the negative electrode pin.

The electrode tab attached to the cap plate 30 among the electrode tabs having the above-described configuration may be welded to the cap plate 30 or the square can 4 by the purpose of implementation and the ease of the process.

The rectangular secondary battery according to the present invention described above can reduce the parts required for sealing, simplify the process, and secure perfect sealing by molding the epoxy 40 in the cap plate 30.

Through the configuration of the present invention described above can solve the problems of the prior art.

Epoxy molding on the top of the cap plate ensures perfect sealing, eliminating the risk of component removal, thereby reducing the incidence of defective rates, and simplifying the manufacturing process by reducing the number of parts required for sealing. Can increase and economical.

Claims (4)

A rectangular secondary battery comprising a rectangular can for accommodating an electrode group wound around a positive electrode, a negative electrode, and a separator, and a cap plate welded to an upper opening of the rectangular can, A hole formed through the cap plate, an electrode tab connected to one of the electrode groups and drawn out through the hole, an insulating case surrounding the electrode tab, and an electrode drawn out through the hole A positive electrode pin coupled to the end of the tab, an epoxy molding applied to an upper surface of the cap plate, and the remaining electrode of the electrode group is welded to one of the cap plate and the square can, and the positive electrode pin is fixed by epoxy molding. , The hole is a rectangular secondary battery, characterized in that it comprises a configuration sealed by epoxy molding. The rectangular rechargeable battery of claim 1, wherein the cap plate includes a recess formed by forming a vertical sidewall at an edge thereof. The prismatic rechargeable battery of claim 1, wherein the insulating case is formed of a polymer material. The prismatic secondary battery of claim 1, wherein the positive electrode pin includes a hemispherical head and a body, and the body is coupled to surround an outer circumference of the positive electrode tab.