KR20150039381A - Secondary battery and method for manufacturing the same - Google Patents

Abstract

In the present invention, disclosed are a secondary battery and a manufacturing method thereof, capable of improving a method for bonding an electrode tab to a battery can of a can type battery. As the can type secondary battery, the secondary battery according to the present invention includes an electrode assembly; the battery can which receives the electrode assembly; and the electrode tab which is attached to the electrode assembly, is outputted to the outside of the electrode assembly, is received in the bottom side of the battery can, and is electrically combined with the battery can. A convex part is formed on the bottom side of the battery can. An insertion hole is formed on the electrode tab to insert the convex part. The convex part is inserted into the insertion hole of the electrode tab.

Description

[0001] The present invention relates to a secondary battery and a manufacturing method thereof,

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a secondary battery, and more particularly, to a secondary battery improved in a method of combining a battery can of an can type battery and an electrode tab, and a method of manufacturing the same.

2. Description of the Related Art Generally, a secondary battery is a battery capable of being charged and discharged unlike a primary battery which can not be charged, and is widely used in electronic devices such as mobile phones, notebook computers, camcorders, and electric vehicles. In particular, lithium secondary batteries have a higher capacity and a higher energy density per unit weight than nickel-cadmium batteries or nickel-hydrogen batteries, which are widely used as power sources for electronic equipment.

These lithium secondary batteries mainly use a lithium-based oxide and a carbonaceous material as a cathode active material and an anode active material, respectively. The lithium secondary battery includes an electrode assembly in which a positive electrode plate and a negative electrode plate each coated with such a positive electrode active material and a negative electrode active material are disposed with a separator interposed therebetween, and an outer casing, that is, a battery case, for sealingly storing the electrode assembly together with the electrolyte solution.

Meanwhile, the lithium secondary battery can be classified into a can type secondary battery in which an electrode assembly is embedded in a metal can, and a pouch type secondary battery in which an electrode assembly is embedded in a pouch of an aluminum laminate sheet, depending on the shape of the battery case. The can-type secondary battery can be classified into a cylindrical battery and a prismatic battery depending on the shape of the metal can. The casing of such a rectangular or cylindrical secondary battery has a cap assembly which is hermetically sealed to the case having an open end, that is, the battery can and the open end of the battery can.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional view partially showing a state in which a rewindable electrode assembly is housed in a battery can according to the prior art; FIG. 1, an electrode assembly 30 to which a negative electrode tab 20 is attached is housed in a battery can 10, and a negative electrode tab 20 is welded to the battery can 10. In FIG. 1, the welded portion is indicated by "e". The negative electrode tab 20 is connected to the bottom cap 11 of the battery can 10 through a current blocking member or the like of a cap assembly (not shown) So that electricity is supplied.

According to the prior art, this negative electrode tab 20 is joined to the bottom 11 of the battery can 10 by welding. Such bonding by the welding method has a problem that the electrical characteristics may vary depending on the welding quality. That is, when the negative electrode tab 20 is not properly welded to the battery can 10, the electrical resistance between the battery can increases, so that the performance of the battery may not be exhibited properly or a safety problem may occur due to heat generation. In this case, there is a problem that the weld joint between the battery can 10 and the negative electrode tab 20 is easily released due to external impact or vibration. On the other hand, when the negative electrode tab is overused to the battery can, there is a risk that the splatter particles will resolidify and adhere to the surface of the battery can.

In addition, since the welding by the welding method depends on the technique of the welding operator, it takes a lot of time and cost, and there is a problem that there is inconvenience that the resistance welding machine used for welding needs to be maintained.

It is an object of the present invention to provide a method of manufacturing a secondary battery improved in a method of combining a battery can and an electrode tab of a can type battery and a secondary battery manufactured by the method .

Other objects and advantages of the present invention will become apparent from the following description, and it will be understood by those skilled in the art that the present invention is not limited thereto. It is also to be understood that the objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations thereof.

According to one aspect of the present invention, there is provided a can type secondary battery comprising: an electrode assembly; A battery can containing the electrode assembly; And an electrode tab which is attached to the electrode assembly and is drawn out to the outside of the electrode assembly and is seated on the bottom of the battery can to electrically connect with the battery can, Wherein the electrode tab is formed with an insertion hole into which the convex portion can be inserted, and the convex portion is inserted into the insertion hole of the electrode tab.

Preferably, the insertion hole has a shape corresponding to the convex portion.

Preferably, the upper end of the convex portion protrudes to the upper portion of the electrode tab, and the protruded portion has a size larger than that of the insertion hole.

Preferably, the electrode tab and the convex portion are welded to each other.

Preferably, the electrode tab is a negative electrode tab.

Preferably, the convex portion is located in the center of the bottom of the battery can.

Preferably, the convex portion includes at least one column having a predetermined height.

More preferably, the height is greater than the thickness of the electrode tab.

Preferably, the column is a prism.

According to an aspect of the present invention, there is provided a battery pack including the secondary battery.

According to an aspect of the present invention, there is provided a method of manufacturing a rechargeable battery, comprising the steps of: preparing a battery can having a convex portion at a bottom of the rechargeable battery; Preparing an electrode assembly to which an electrode tab having an insertion hole for inserting the convex portion is attached; And inserting the convex portion into the insertion hole of the electrode tab.

Preferably, the method further comprises compressing the electrode tab and the convex portion by pressing the battery can in the up and down direction from the inside and the outside of the battery can around the bottom of the battery can.

According to the present invention, the battery can and the electrode tab are coupled by the pressing method, so that the coupling force between the battery can and the electrode tab can be stably secured.

In addition, according to one aspect of the present invention, there is an advantage that, when the battery can and the electrode tab are combined, welding is not required, or even if welding is performed, only a little welding can be performed compared with the conventional case. Therefore, according to the present invention, there is no problem caused by conventional beauty welding, weak welding, over-welding, etc., and the cost and time for maintenance and repair of the resistance welder are greatly reduced.

According to an aspect of the present invention, the protrusions of the battery can and the shapes of the insertion holes of the electrode tabs to be engaged with the protrusions of the battery can correspond to each other. By forming the insertion holes of the electrode tabs into a square shape, It is possible to reduce the flow of the electrode tab in the process of joining the electrode tabs. Therefore, the battery can and the electrode tab can be stably combined.

In addition, the present invention can have various other effects, and other effects of the present invention can be understood by the following description, and can be more clearly understood by the embodiments of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate preferred embodiments of the invention and, together with the description of the invention given below, serve to further the understanding of the technical idea of the invention. And should not be construed as limiting.
BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional view partially showing a state in which a rewindable electrode assembly is housed in a battery can according to the prior art; FIG.
2 is an exploded perspective view of a secondary battery according to an embodiment of the present invention.
3 is an assembled perspective view of Fig.
Fig. 4 is an assembled sectional view of Fig. 2. Fig.
FIG. 5 is a schematic view illustrating a process of pressing and bonding a battery can and an electrode tab according to an embodiment of the present invention. Referring to FIG.
6 is an assembled cross-sectional view of a secondary battery according to another embodiment of the present invention.
7 is an exploded perspective view of a secondary battery according to another embodiment of the present invention.
8 is an exploded perspective view of a secondary battery according to another embodiment of the present invention.
9 is an assembled perspective view of Fig.
10 is a flowchart schematically illustrating a method of manufacturing a secondary battery according to an embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Prior to this, terms and words used in the present specification and claims should not be construed as limited to ordinary or dictionary terms, and the inventor should appropriately interpret the concepts of the terms appropriately It should be construed as meaning and concept consistent with the technical idea of the present invention based on the principle that it can be defined.

Therefore, the embodiments described in this specification and the configurations shown in the drawings are merely the most preferred embodiments of the present invention and do not represent all the technical ideas of the present invention. Therefore, It is to be understood that equivalents and modifications are possible.

In the following description, well-known functions or constructions are not described in detail since they would obscure the invention in unnecessary detail.

The embodiments of the present invention are provided to explain the present invention more fully to the ordinary artisan, so that the shape and size of the components in the drawings may be exaggerated, omitted or schematically shown for clarity. Thus, the size or ratio of each component does not entirely reflect the actual size or ratio.

FIG. 2 is an exploded perspective view of a secondary battery according to an embodiment of the present invention, FIG. 3 is an assembled perspective view of FIG. 2, and FIG. 4 is an assembled sectional view of FIG.

2 to 4, the secondary battery according to the present invention includes an electrode assembly 300, a battery can 100, and an electrode tab 200. 2 to 4 illustrate a part of the battery can 100. The secondary battery according to the present invention may further include a cap assembly 100 having a cap assembly coupled to an upper portion of the battery can 100. [ On the other hand, in order not to obscure the gist of the present invention, the electrode assembly is not shown in FIGS. 2 and 3, and the electrode assembly 300 is shown in broken lines in FIG.

In the electrode assembly 300, a positive electrode plate and a negative electrode plate are disposed with the separator interposed therebetween and housed in the battery can 100. At this time, the electrode assembly 300 may be wound and disposed in the form of a jelly-roll. In this case, the electrode assembly 300 may also be referred to as a jelly-roll.

The electrode plates of the electrode assembly 300 are formed as a structure in which a current collector is coated with an active material slurry. The slurry may be formed by stirring a granular active material, an auxiliary conductor, a binder, a plasticizer, . The electrode plate may have an uncoated portion where the slurry is not applied to the starting end and the end of the current collector in the direction in which the electrode plates are wound, and the electrode tab 200 corresponding to each electrode plate may be attached to the uncoated portion.

The cathode tab may be attached to the upper end of the electrode assembly 300 to be connected to a cap assembly (not shown) that forms a cathode terminal. The cathode tab may be attached to the lower end of the electrode assembly 300, To the bottom of the battery can 100 which forms the battery can 100.

The cap assembly is coupled to the open end of the battery can 100 to seal the battery can 100. Such cap assemblies may include components such as a top cap, a safety element, a safety vent, an insulating member, a current blocking member, and a gasket.

The present invention may be embodied in many other forms without departing from the spirit or essential characteristics thereof. For example, it should be understood that the present invention is not limited thereto. Detailed description is omitted in the specification.

The electrode assembly 300 is housed in the battery can 100. In this battery can 100, a space for accommodating the electrode assembly 300 is formed. The battery can 100 can be filled with the electrolyte solution as well as the electrode assembly 300. The battery can 100 is made of a lightweight conductive metal material such as aluminum, stainless steel, or an alloy thereof, and has an open top portion and an open bottom portion 110 opposed thereto And may have a cylindrical or prismatic structure.

Particularly, in the battery can 100 according to the present invention, the protrusion 111 may be provided in the bottom 110 of the battery can 100. The convex portion 111 may be formed by protruding at least a part of the bottom portion 110 inside the battery can 100 and the convex portion 111 may be formed in the insertion hole 210 of the electrode tab 200 As shown in Fig.

The electrode tab 200 may be attached to the electrode assembly 300 and drawn out of the electrode assembly 300. The electrode tab 200 is seated on the bottom 110 of the battery can 100 and can be stably coupled to the battery can 100.

In particular, the electrode tab 200 according to the present invention is formed with an insertion hole 210 through which the convex portion 111 of the battery can 100 can be inserted. 3 and 4, the convex portion 111 of the battery can 100 is inserted into the insertion hole 210 of the electrode tab 200 so that the battery can 100 and the electrode tab 200 are inserted into the insertion hole 210 of the electrode tab 200, Can be electrically coupled.

Preferably, the insertion hole 210 may have a shape corresponding to the convex portion 111. In other words, the convex portion 111 has a shape corresponding to the shape of the insertion hole 210, so that the convex portion 111 can be firmly coupled when inserted into the insertion hole 210 of the electrode tab 200. For example, as shown in FIGS. 2 to 4, the inside of the insertion hole 210 may be formed in a circular shape, and the convex portion 111 may be formed in a cylindrical shape to be inserted into the insertion hole 210.

The upper end of the convex portion 111 protrudes to the upper portion of the electrode tab 200 and the size of the protruded portion may be larger than the size of the insertion hole 210 of the electrode tab 200. As described above, the protruded portion of the protruded portion may be formed to have a size larger than the size of the insertion hole of the electrode tab, by a process of pressing the protruded portion of the protruded portion. This will be described in more detail with reference to Fig.

FIG. 5 is a schematic view illustrating a process of pressing and bonding a battery can and an electrode tab according to an embodiment of the present invention. Referring to FIG.

Fig. 5 (a) is a view showing a state where the convex portion of the battery can according to the embodiment of the present invention is inserted into the electrode tab, 1 is a perspective view illustrating a battery can according to an embodiment of the present invention.

5A, the convex portion 111 of the battery can 100 is inserted into the insertion hole 210 of the electrode tab 200, and the convex portion 111 of the battery can 100 is connected to the outside of the bottom portion 110 of the battery can 100 A compression jig (z) is located inside the bottom part (110) of the battery can (100). 5 (a), the upper pressing jig z presses the convex portion 111 of the battery can 100 from the upper portion to the lower portion and the lower pressing jig z presses the convex portion 111 of the battery can 100 from the lower portion to the upper portion And presses the bottom portion 110 of the battery can 100. The upper end of the convex portion 111 protruding to the upper portion of the electrode tab 200 is subjected to upward and downward pressure.

As a result, the convex portion 111 protruding to the upper portion of the electrode tab 200 is compressed as shown in FIG. 5 (b), so that the battery can 100 and the electrode tab 200 are tightly coupled. The size of the upper end of the convex portion 111 protruding to the upper portion of the electrode tab 200 may be larger than the size of the insertion hole 210 through the compression of the compression jig z. In other words, the diameter d1 of the upper end of the convex portion 111 can be larger than the diameter d2 of the insertion hole 210 (d1> d2).

If the battery can 100 and the electrode tab 200 are coupled by the press-fitting, no problem due to the beauty contact, the weak welding, or the over-welding due to the welding method is prevented. Since the size of the upper end of the convex portion 111 protruding to the upper portion of the electrode tab 200 is larger than that of the insertion hole 210, The engaging of the engaging portion 200 is not easily released.

Also, preferably, the electrode tab 200 and the convex portion 111 can be welded together. In other words, not only the convex portion 111 is inserted into the insertion hole 210 of the electrode tab 200 but also the electrode tab 200 and the convex portion 111 can be welded.

When the welding connection method is added to the insertion coupling method described above, the problem of the welding connection method can be compensated for, so that the coupling force between the electrode tab 200 and the insertion hole 210 is further increased, Thereby improving the electrical conductivity of the substrate 100.

6 is a cross-sectional view of a secondary battery according to another embodiment of the present invention. 6A and 6B, not only the convex portion 111 is inserted into the insertion hole 210 of the electrode tab 200, but also the battery can 100 and the electrode tab 200, Is welded. At this time, as shown in FIG. 6 (a), the inner circumferential surface of the insertion hole 210 may be welded, and the bottom 110 of the battery can 100 may be welded as shown in FIG. 6 (b). More preferably, the electrode tab 200 and the battery can 100 are press-coupled to each other and welded along the outer circumference of the upper end of the convex portion 111, as shown in FIG. 6 (c). However, such a welding portion (e) is an example, and the present invention is not limited to such a welding position or a welding portion.

Preferably, the convex portion 111 is located in the center of the bottom portion 110 of the battery can 100. In the case of the wound type electrode assembly 300 housed in the battery can 100, a void space o exists in the winding center portion. 2 to 6, when the convex portion 111 of the battery can 100 is positioned at the center of the bottom of the battery can 100, the convex portion 111 of the battery can 100 contacts the electrode assembly 300 (O) at the winding center portion of the winding core (1). This makes it possible to increase the efficiency of utilization of space in the battery can 100. When the compression jig z shown in Fig. 5 is used, the upper compression jig z is wound around the winding center of the electrode assembly 300 So that the secondary battery can be conveniently manufactured.

Also preferably, the electrode tab 200 may be a negative electrode tab. Since the negative electrode tab is often electrically coupled to the bottom portion 110 of the battery can 100, the electrode tab 200 described above is preferably a negative electrode tab.

Also, preferably, the convex portion 111 may include at least one column having a predetermined height.

7 is an exploded perspective view of a secondary battery according to another embodiment of the present invention. Referring to Fig. 7, the convex portion 111 includes three cylindrical columns having a predetermined height. Three circular insertion holes 210 are formed in the electrode tab 200 corresponding to the convex portion 111 so that three cylindrical columns can be inserted into the electrode tab 200.

More preferably, the height of the column is larger than the thickness of the electrode tab 200. 2 to 7, it is preferable that the height h of the column included in the convex portion 111 is larger than the thickness w of the electrode tab 200 (h1> w1, h2> w2 , h3 > w3).

Preferably, the column is a prism.

FIG. 8 is an exploded perspective view of a secondary battery according to another embodiment of the present invention, and FIG. 9 is an assembled perspective view of FIG.

8 and 9, the column included in the convex portion 111 has a rectangular column shape. Correspondingly, the electrode tab 200 has a rectangular insertion hole 210 formed therein. According to this embodiment, the electrode tab 200 does not rotate around the convex portion 111 as shown by an arrow in FIG. 9 due to the corners formed in the convex portion and the insertion hole. Therefore, the battery can 100 can be firmly coupled to the insertion hole 210 and the flow of the electrode assembly 200 with the electrode tab 200 and the electrode tab 200, Can be minimized. It is a matter of course that other rectangular prisms such as a triangular prism or a pentagonal prism can be employed as the quadrangular prism as an example.

The secondary battery according to the present invention can be applied to a battery pack. That is, the battery pack according to the present invention includes the above-described secondary battery. In this case, the battery pack may further include a battery pack management device for measuring and managing the voltage, current, and / or temperature of the battery, and the like.

Hereinafter, a method of manufacturing a secondary battery according to the present invention will be described.

10 is a flowchart schematically illustrating a method of manufacturing a secondary battery according to an embodiment of the present invention.

Referring to FIG. 10, in order to manufacture a secondary battery according to the present invention, a battery can 100 is prepared (S110). The battery can 100 prepared here may have a convex portion 111 at the bottom 110 of the battery can 100.

Preferably, the convex portion 111 may include at least one column having a predetermined height. More preferably, the height is larger than the thickness of the electrode tab 200, and the column is preferably a prism. Preferably, the convex portion 111 is located in the center of the bottom portion 110 of the battery can 100.

Next, the electrode assembly 300 to which the electrode tab 200 is attached is prepared. The electrode assembly 300 may be provided with an insertion hole 210 through which the convex portion 111 can be inserted. According to the method of manufacturing a secondary battery according to an embodiment of the present invention, the insertion hole 210 is formed in the electrode tab 200 at step S120, the electrode tab 200 is attached to the electrode assembly 300 The electrode assembly 200 having the electrode tab 200 formed with the insertion hole 210 may be prepared by bending the electrode tab 200 as shown in FIGS. However, the above S120 to S140 are examples, and the present invention is not necessarily limited to such a method or order.

Preferably, the electrode tab 200 may be a negative electrode tab, and preferably, the insertion hole 210 may have a shape corresponding to the convex portion 111.

Next, the prepared electrode assembly 300 is received (S150). At this time, the convex portion 111 is inserted into the insertion hole 210 of the electrode tab 200 (S160). The protrusion 111 is inserted into the insertion hole 210 of the electrode tab 200 and inserted into the battery can 100 from the inner and outer portions of the battery can 100 around the bottom portion 110 of the battery can 100 The electrode tab 200 and the convex portion 111 can be press-coupled to each other (S170).

Next, the secondary battery according to the present invention can be manufactured by injecting an electrolyte solution into the battery can 100 (S180), sealing the cap assembly to the upper part of the battery can 100 and sealing it (S190).

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not to be limited to the details thereof and that various changes and modifications will be apparent to those skilled in the art. And various modifications and variations are possible within the scope of the appended claims.

In the foregoing description or drawings, the use of terms such as upper, lower, inner, and outer is used to distinguish one element from another, and is merely an instrumental concept for improving the efficiency of explanation , Physical location, posterior relations, etc., should not be construed as being used to distinguish by absolute criteria.

The features described in the individual embodiments herein may be combined and implemented in a single embodiment. Conversely, various features described herein in a single embodiment may be implemented in various embodiments individually or in a suitable subcombination.

100: battery can 200: electrode tab 300: electrode assembly
110: bottom part 111: convex part
210: insertion hole

Claims (12)

In the can type secondary battery,
An electrode assembly;
A battery can containing the electrode assembly; And
And an electrode tab attached to the electrode assembly and drawn out to the outside of the electrode assembly and seated on the bottom of the battery can to electrically connect with the battery can,
Wherein a convex portion is provided in a bottom portion of the battery can,
Wherein the electrode tab is formed with an insertion hole into which the convex portion can be inserted,
And the convex portion is inserted into the insertion hole of the electrode tab. The method according to claim 1,
Wherein the insertion hole has a shape corresponding to the convex portion. The method according to claim 1,
Wherein an upper end of the convex portion protrudes to an upper portion of the electrode tab, and a size of the protruded portion is larger than a size of the insertion hole. The method according to claim 1,
And the electrode tab and the convex portion are welded together. The method according to claim 1,
Wherein the electrode tab is a negative electrode tab. The method according to claim 1,
And the convex portion is located in the center of the bottom of the battery can. The method according to claim 1,
Wherein the convex portion includes at least one column having a predetermined height. 8. The method of claim 7,
Wherein the height is greater than the thickness of the electrode tab. 8. The method of claim 7,
Wherein the column is a prismatic column. A battery pack comprising a secondary battery according to any one of claims 1 to 9. In the can type secondary battery manufacturing method,
Preparing a battery can having a convex portion at the bottom of the battery;
Preparing an electrode assembly to which an electrode tab having an insertion hole for inserting the convex portion is attached; And
Inserting the convex portion into the insertion hole of the electrode tab;
The method comprising the steps of: 12. The method of claim 11,
Further comprising the step of compressing and bonding the electrode tab and the convex portion by pressing the battery can in the vertical direction from the inside and the outside of the battery can around the bottom of the battery can.

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