KR20210138400A - The Apparatus And The Method For Welding Electrode Tabs - Google Patents

Abstract

The present invention relates to an electrode tab welding apparatus and a method thereof. The electrode tab welding apparatus according to an embodiment of the present invention for solving an above problem comprises: a first laser generating unit for cutting a plurality of electrode tabs by irradiating a first laser to the plurality of electrode tabs protruding from an electrode assembly manufactured by stacking the electrode and a separator, and forming a welding unit by primary welding end units of the plurality of electrode tabs; and a first fixing jig for fixing the plurality of electrode tabs to each other. When the end units of the plurality of electrode tabs are firstly welded, the first laser generating unit irradiates a second laser to the centers of the plurality of electrode tabs to perform secondary welding of the centers of the plurality of electrode tabs. An objective of the present invention is to provide the electrode tap welding apparatus for improving output by preventing an increase in resistance, and the method thereof.

Description

The Apparatus And The Method For Welding Electrode Tabs

The present invention relates to an electrode tab welding apparatus and method, and more particularly, the electrode tabs are not firmly in close contact with each other, thereby reducing the strength and preventing disconnection and disconnection from adjacent electrode tabs, and preventing an increase in resistance to output It relates to an electrode tap welding apparatus and method for improving the

In general, types of secondary batteries include a nickel cadmium battery, a nickel hydrogen battery, a lithium ion battery, and a lithium ion polymer battery. These secondary batteries are not only small products such as digital cameras, P-DVDs, MP3Ps, mobile phones, PDAs, Portable Game Devices, Power Tools and E-bikes, but also large products requiring high output such as electric and hybrid vehicles and surplus power generation. It is also applied and used in power storage devices that store power or renewable energy and power storage devices for backup.

In order to manufacture such a secondary battery, first, a positive electrode active material slurry is applied to a positive electrode current collector, and a negative electrode active material slurry is applied to a negative electrode current collector to prepare a positive electrode and a negative electrode, respectively, and the amount of the separator By laminating on the side, an electrode assembly having a predetermined shape is formed. Then, the electrode assembly is accommodated in the battery case, and the electrolyte is injected and then sealed.

Such secondary batteries are classified into pouch type and can type according to the material of the battery case for accommodating the electrode assembly. The pouch type accommodates the electrode assembly in a pouch made of a flexible polymer material having an irregular shape. And, in the can type, the electrode assembly is accommodated in a case made of a material such as metal or plastic having a constant shape.

The pouch-type battery case is manufactured by forming a cup portion by performing drawing molding on a pouch film having flexibility. This drawing molding is performed by inserting a pouch film into a press and applying pressure to the pouch film with a punch to stretch the pouch film. When the cup portion is formed, the electrode assembly is accommodated in the accommodating space of the cup portion, the battery case is folded, and the sealing portion is sealed to manufacture a secondary battery.

On the other hand, a plurality of electrodes are stacked in one electrode assembly, and in order to easily supply electricity generated from these electrodes to the outside, an electrode tab is formed for each electrode. Then, the electrode tabs are connected by welding the positive electrode tabs to the positive electrode tabs and the negative electrode tab to the negative electrode tabs. Then, it is connected to one positive lead and one negative lead, respectively.

Conventionally, ultrasonic welding was performed when connecting electrode tabs. Specifically, using a horn and anvil in which a plurality of protrusions were formed to protrude, pressure was applied from both sides of the electrode tab and ultrasonic waves were applied. Then, the vibration energy of the horn and anvil was converted into thermal energy by friction, and welding was performed. However, when such ultrasonic welding is performed, the welding quality is excellent in the portion in which the projections are embedded in the electrode tab, but the welding quality in the portion in which the projections are not embedded in the electrode tab is deteriorated. Accordingly, there is a problem in that the non-welded portion of the electrode tab is sporadically distributed, and the output is lowered by increasing the resistance. Further, among the plurality of electrode tabs, some of the electrode tabs did not firmly adhere to the neighboring electrode tabs, so that the strength was lowered, and there was also a problem of disconnection and disconnection from the neighboring electrode tabs.

Japanese Publication No. 2016-030280

The problem to be solved by the present invention is an electrode tab welding apparatus for improving output by preventing the electrode tabs from tightly adhering to the lowering strength and detaching and disconnecting from the neighboring electrode tabs, and preventing an increase in resistance, and to provide a way

The problems of the present invention are not limited to the problems mentioned above, and other problems not mentioned will be clearly understood by those skilled in the art from the following description.

In an electrode tab welding apparatus according to an embodiment of the present invention for solving the above problems, a first laser is irradiated to a plurality of electrode tabs protruding from an electrode assembly manufactured by stacking an electrode and a separator to cut the plurality of electrode tabs a first laser generator for forming a welding part by first welding the ends of the plurality of electrode tabs; and a first fixing jig for fixing the plurality of electrode tabs to each other, wherein the first laser generating unit applies a second laser to the center of the plurality of electrode tabs when the ends of the plurality of electrode tabs are first welded. By irradiating, the central portions of the plurality of electrode tabs are secondarily welded.

In addition, the first fixing jig may include: a first upper jig for fixing the electrode tabs from above; and a first lower jig for fixing the electrode tabs from below.

Also, the first upper jig may have a first through hole penetrating therethrough.

In addition, the first laser generator may irradiate a second laser toward the first through hole to perform secondary welding of the plurality of electrode tabs.

In addition, the first laser generating unit may perform primary welding by irradiating a first laser to the outside of the first fixing jig.

Also, the first laser and the second laser may have different outputs.

In addition, when the electrode leads are seated on one surface of the plurality of electrode tabs, a third laser is irradiated to the electrode tabs and the electrode leads, and a second laser generator for tertiary welding the electrode tabs and the electrode leads is further included. can do.

In addition, when the electrode leads are seated on one surface of the plurality of electrode tabs, a second fixing jig for fixing the electrode tabs and the electrode leads to each other may be further included.

In addition, the second fixing jig, a second upper jig for fixing the electrode tab and the electrode lead from above; and a second lower jig for fixing the electrode tab and the electrode lead from below.

In addition, the second upper jig may have a second through hole penetrating therethrough.

In addition, the second laser generator may irradiate a third laser toward the second through hole to weld the electrode tab and the electrode lead.

In addition, the first fixing jig may include a suction unit for sucking dust generated by primary welding or secondary welding and discharging to the outside.

In addition, the first fixing jig may include a spraying unit for spraying an inert gas toward the electrode tab.

An electrode tab welding method according to an embodiment of the present invention for solving the above problems comprises the steps of: manufacturing an electrode assembly by stacking an electrode and a separator; forming a weld by first welding ends of the plurality of electrode tabs while cutting the plurality of electrode tabs by irradiating a first laser to the plurality of electrode tabs protruding from the electrode assembly; and irradiating, by the first laser generator, a second laser to the plurality of electrode tabs, and secondary welding the central portions of the plurality of electrode tabs.

The method may further include fixing the plurality of electrode tabs by a first fixing jig after the manufacturing of the electrode assembly and before the primary welding.

In addition, after the second welding step, the step of seating the electrode leads on one surface of the plurality of electrode tabs; and irradiating a third laser to the electrode tab and the electrode lead by a second laser generating unit, and thirdly welding the electrode tab and the electrode lead.

In addition, after the step of seating the electrode lead and before the third welding step, the method may further include a second fixing jig fixing the electrode tab and the electrode lead to each other.

In addition, the second welding may be performed by moving the first laser generator while the electrode assembly is fixed.

Other specific details of the invention are included in the detailed description and drawings.

According to the embodiments of the present invention, there are at least the following effects.

Since the electrode tabs are welded by laser welding rather than ultrasonic welding, it is possible to prevent the electrode tabs from being tightly adhered or disconnected, and accordingly, the overall resistance of the electrode tabs is not reduced, so that the output of the secondary battery can be improved. .

The effect according to the present invention is not limited by the contents exemplified above, and more various effects are included in the present specification.

1 is an assembly view of a secondary battery according to an embodiment of the present invention.
2 is a perspective view of a secondary battery according to an embodiment of the present invention.
3 is a schematic diagram illustrating a state in which a plurality of conventional electrode tabs are welded to each other.
4 is a schematic diagram illustrating a state in which ends of a plurality of electrode tabs are cut in the related art.
5 is a schematic diagram illustrating a state in which an electrode lead is connected to a conventional electrode tab.
6 is a flowchart illustrating an electrode tab welding method according to an embodiment of the present invention.
7 is a schematic diagram illustrating a state in which a plurality of electrode tabs are in contact with each other according to an embodiment of the present invention.
8 is a schematic diagram illustrating a state in which the first laser generating unit cuts the end of the electrode tab according to an embodiment of the present invention.
9 is a schematic diagram illustrating a state in which the first laser generator welds the center of the electrode tab according to an embodiment of the present invention.
10 is a schematic diagram illustrating a state in which a second laser generating unit welds an electrode tab and an electrode lead to each other according to an embodiment of the present invention.

Advantages and features of the present invention and methods of achieving them will become apparent with reference to the embodiments described below in detail in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but may be implemented in various different forms, and only these embodiments allow the disclosure of the present invention to be complete, and common knowledge in the art to which the present invention pertains It is provided to fully inform those who have the scope of the invention, and the present invention is only defined by the scope of the claims. Like reference numerals refer to like elements throughout.

Unless otherwise defined, all terms (including technical and scientific terms) used herein may be used with the meaning commonly understood by those of ordinary skill in the art to which the present invention belongs. In addition, terms defined in a commonly used dictionary are not to be interpreted ideally or excessively unless clearly defined in particular.

The terminology used herein is for the purpose of describing the embodiments and is not intended to limit the present invention. As used herein, the singular also includes the plural unless specifically stated otherwise in the phrase. As used herein, “comprises” and/or “comprising” does not exclude the presence or addition of one or more other components in addition to the stated components.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is an assembly view of a secondary battery 1 according to an embodiment of the present invention, and FIG. 2 is a perspective view of the secondary battery 1 according to an embodiment of the present invention.

As shown in FIG. 1 , the pouch-type secondary battery 1 according to an embodiment of the present invention includes an electrode assembly 10 and the electrode assembly ( 10) includes a pouch-type battery case 13 for accommodating it therein.

In order to manufacture the pouch-type secondary battery 1, first, a slurry in which an electrode active material, a binder, and a plasticizer are mixed is applied to a positive electrode current collector and a negative electrode current collector to prepare electrodes such as a positive electrode and a negative electrode. The electrode assembly 10 of a predetermined shape is formed by stacking this on both sides of a separator, and then, the electrode assembly 10 is inserted into the battery case 13, and the electrolyte is injected and then sealed.

Specifically, the electrode assembly (Electrode Assembly, 10) is a laminate structure having two types of electrodes, a positive electrode and a negative electrode, and a separator interposed between the electrodes or disposed on the left or right side of any one electrode to insulate the electrodes from each other. can be The laminated structure may have various shapes without limitation, such as a positive electrode and a negative electrode having a predetermined standard may be stacked with a separator interposed therebetween, and may be wound in the form of a jelly roll. Two types of electrodes, that is, a positive electrode and a negative electrode, have a structure in which an active material slurry is applied to an electrode current collector in the form of a metal foil or metal mesh including aluminum and copper, respectively. In general, the slurry may be formed by stirring a granular active material, an auxiliary conductor, a binder, and a plasticizer in a state in which a solvent is added. The solvent is removed in a subsequent process.

As shown in FIG. 1 , the electrode assembly 10 includes an electrode tab 11 . The electrode tab 11 is respectively connected to the positive electrode and the negative electrode of the electrode assembly 10 , and protrudes to the outside of the electrode assembly 10 , and serves as a path through which electrons can move between the inside and the outside of the electrode assembly 10 . . The electrode current collector of the electrode assembly 10 includes a portion to which the electrode active material is applied and a distal portion to which the electrode active material is not applied, that is, an uncoated portion. In addition, the electrode tab 11 may be formed by cutting the uncoated area or may be formed by connecting a separate conductive member to the uncoated area by ultrasonic welding or the like. As shown in FIG. 1 , the electrode tabs 11 may protrude side by side from one side of the electrode assembly 10 in the same direction, but are not limited thereto and may protrude in different directions.

An electrode lead 12 for supplying electricity to the outside of the secondary battery 1 is connected to the electrode tab 11 of the electrode assembly 10 . A part of the electrode lead 12 is surrounded by the insulating portion 14 . The insulating part 14 is located limited to the sealing part 134 to which the upper case 131 and the lower case 132 of the battery case 13 are thermally fused, and the electrode lead 12 is attached to the battery case 13 . glue it together In addition, electricity generated from the electrode assembly 10 is prevented from flowing to the battery case 13 through the electrode lead 12 , and the sealing of the battery case 13 is maintained. Accordingly, the insulating portion 14 is made of a non-conductive material that does not conduct electricity well. In general, as the insulating portion 14, an insulating tape that is easy to attach to the electrode lead 12 and has a relatively thin thickness is used a lot, but it is not limited thereto and various members can be used as long as it can insulate the electrode lead 12. have.

The electrode lead 12 has one end connected to the positive electrode tab 111 , one end connected to the positive electrode lead 121 and the negative electrode tab 112 extending in the protruding direction of the positive electrode tab 111 , and the negative electrode tab 112 . ) includes a negative lead 122 extending in the protruding direction. On the other hand, as shown in FIG. 1 , the positive lead 121 and the negative lead 122 both have the other end protruding to the outside of the battery case 13 . Accordingly, electricity generated inside the electrode assembly 10 may be supplied to the outside. In addition, since the positive electrode tab 111 and the negative electrode tab 112 are formed to protrude in various directions, respectively, the positive electrode lead 121 and the negative electrode lead 122 may also extend in various directions.

The material of the positive lead 121 and the negative lead 122 may be different from each other. That is, the positive electrode lead 121 may be made of the same aluminum (Al) material as the positive electrode current collector, and the negative electrode lead 122 may be made of the same copper (Cu) material as the negative electrode current collector or nickel (Ni) coated copper. And a portion of the electrode lead 12 protruding to the outside of the battery case 13 becomes a terminal part, and is electrically connected to the external terminal.

The battery case 13 is a pouch made of a flexible material to accommodate the electrode assembly 10 therein. Hereinafter, the battery case 13 will be described as a pouch. When the pouch film 135 having flexibility is formed by drawing using a punch or the like, a portion is elongated to form the cup portion 133 including the pocket-shaped accommodation space 1331 , thereby forming the battery case 13 . manufactured. The battery case 13 accommodates and seals the electrode assembly 10 so that a portion of the electrode lead 12, that is, the terminal portion is exposed. As shown in FIG. 1 , the battery case 13 includes an upper case 131 and a lower case 132 . A cup part 133 is formed in the lower case 132 to provide an accommodating space 1331 accommodating the electrode assembly 10 , and the upper case 131 has the electrode assembly 10 in the battery case 13 . The accommodating space 1331 is covered from the upper part so as not to be separated to the outside of the . And the sealing part 134 is sealed to seal the accommodation space 1331 . In this case, the cup portion 133 having the accommodation space 1331 is also formed in the upper case 131 to accommodate the electrode assembly 10 from the upper portion. The upper case 131 and the lower case 132 may be manufactured by connecting one side to each other as shown in FIG.

When the electrode lead 12 is connected to the electrode tab 11 of the electrode assembly 10 and the insulating part 14 is formed on a portion of the electrode lead 12 , the cup part 133 of the lower case 132 is provided. The electrode assembly 10 is accommodated in the accommodation space 1331 , and the upper case 131 covers the space from the top. Then, the electrolyte is injected therein, and as shown in FIG. 2 , the sealing part 134 extending outwardly from the edges of the upper case 131 and the lower case 132 is sealed. The electrolyte is to move lithium ions generated by the electrochemical reaction of the electrode during charging and discharging of the secondary battery 1, and a polymer using a non-aqueous organic electrolyte or a polymer electrolyte, which is a mixture of lithium salt and high-purity organic solvents. may include. Through this method, as shown in FIG. 2 , the pouch-type secondary battery 1 may be manufactured.

3 is a schematic diagram illustrating a state in which a plurality of conventional electrode tabs 11 are welded to each other.

When ultrasonic welding of a plurality of electrode tabs 11 according to the related art, first, a plurality of electrode tabs 11 to be welded are seated on a welding surface of an anvil 32 , and then, as shown in FIG. 3 , the horn A pressure was applied to the electrode tabs 11 with the welding surface of (Horn, 31). At this time, on the welding surface of the horn 31, a plurality of protrusions were continuously arranged in a fixed order and formed. As the plurality of projections are driven into the plurality of electrode tabs 11 , patterns recessed in a shape corresponding to the projections are formed on the outermost surface of the electrode tab 11 . Then, when ultrasonic waves having a high frequency of about 20 kHz were applied, vibration energy of the horn 31 and the anvil 32 was converted into thermal energy by friction and welding was performed.

4 is a schematic diagram illustrating a state in which ends of a plurality of electrode tabs 11 are cut in the related art.

As shown in FIG. 4 , the cutter 33 moved from the top to the bottom on the plurality of electrode tabs 11 welded to each other, and the end of the electrode tab 11 was cut along the cutting line C. . Thereby, the length of the electrode tab 11 was appropriately adjusted, and the ends of the electrode tab 11 were made uniform.

5 is a schematic view showing a state in which the electrode lead 12 is connected to the conventional electrode tab 11 .

After ultrasonic welding of the plurality of electrode tabs 11 was completed, one end of the electrode lead 12 was connected to the electrode tab 11 . To this end, as shown in FIG. 5 , laser welding was performed on the electrode tab 11 and the electrode lead 12 using the laser generator 34 . Accordingly, the electrode tab 11 and the electrode lead 12 could be connected to each other.

As described above, according to the conventional electrode tab welding method, ultrasonic welding was performed between the electrode tabs 11 . That is, it was pressed from both sides of the electrode tab 11 using the horn 31 and the anvil 32 in which a plurality of protrusions were formed to protrude. However, the portion in which the projections are embedded in the electrode tab 11 had excellent welding quality, but the portion in which the projections were not embedded in the electrode tab 11 had poor welding quality. Therefore, there is a problem in that the non-welded portion of the electrode tab 11 is sporadically distributed, and the output is lowered due to an increase in resistance. Further, among the plurality of electrode tabs 11 , some of the electrode tabs 11 did not firmly adhere to the neighboring electrode tabs 11 , so the strength was lowered, and there was also a problem of disconnection and disconnection from the neighboring electrode tabs 11 . .

6 is a flowchart illustrating an electrode tab welding method according to an embodiment of the present invention.

According to an embodiment of the present invention, since the electrode tabs 11 are welded by laser welding rather than ultrasonic welding, it is possible to prevent the electrode tabs 11 from being tightly adhered or disconnected, and accordingly, the electrode tabs 11 ) do not decrease, so the output of the secondary battery 1 may be improved.

To this end, an electrode tab welding method according to an embodiment of the present invention includes manufacturing an electrode assembly 10 by stacking an electrode and a separator; A first laser generator 24 irradiates a first laser 241 to the plurality of electrode tabs 11 protruding from the electrode assembly 10 to cut the plurality of electrode tabs 11 , forming a welding part 113 by first welding an end of the electrode tab 11; and irradiating, by the first laser generator 24, a second laser 242 to the plurality of electrode tabs 11 to perform secondary welding of central portions of the plurality of electrode tabs 11 . In addition, after the second welding step, the step of seating the electrode leads 12 on one surface of the plurality of the electrode tabs 11; and a second laser generator 26 irradiates a third laser 261 to the electrode tab 11 and the electrode lead 12 , thereby tertiarily irradiating the electrode tab 11 and the electrode lead 12 . It may include welding.

Hereinafter, the contents of each step of the flowchart shown in FIG. 6 will be described together with FIGS. 7 to 10 .

7 is a schematic diagram illustrating a state in which a plurality of electrode tabs 11 are in contact with each other according to an embodiment of the present invention.

As described above, the electrode assembly 10 is manufactured by alternately stacking an electrode including a plurality of positive and negative electrodes and a separator ( S601 ). In order to easily supply electricity generated from the electrodes to the outside, an electrode tab 11 is formed for each electrode. The electrode tab 11 is formed to protrude from one side of the electrode assembly 10 to the outside, and includes a positive electrode tab 111 protruding from the positive electrode and a negative electrode tab 112 protruding from the negative electrode.

Since a plurality of positive and negative electrodes stacked on the electrode assembly 10 are formed, the electrode tab 11 is also formed in plurality. In order to perform the electrode tab welding method according to an embodiment of the present invention, first, the plurality of electrode tabs 11 are brought into contact with each other ( S602 ). In this case, the positive electrode tab 111 is connected to the positive electrode tab 111 , and the negative electrode tab 112 is connected to the negative electrode tab 112 by contacting each other. In order to bring the electrode tabs 11 into contact with each other, as shown in FIG. 7 , the electrode tab press 22 presses the remaining electrode tabs 11 from the top to the bottom toward the electrode tab 11 located at the lowermost end and bends it. By doing so, they can be brought into contact with each other. However, the present invention is not limited thereto, and toward the uppermost electrode tab 11 , the electrode tab press 22 may press and bend the remaining electrode tabs 11 from the bottom to the top to make contact with each other.

In order to prevent other components of the electrode assembly 10 from moving when the electrode tabs 11 are bent, the electrode assembly fixing part 21 may press and fix the electrode assembly 10 . Furthermore, the electrode assembly fixing part 21 continues to the electrode assembly 10 even if the steps of welding the plurality of electrode tabs 11 and welding the electrode tabs 11 and the electrode leads 12 to each other are performed later. It can also be fixed by pressing.

8 is a schematic diagram illustrating a state in which the first laser generating unit 24 cuts the end of the electrode tab 11 according to an embodiment of the present invention.

As shown in FIG. 8 , an electrode tab welding apparatus according to an embodiment of the present invention includes a first laser ( a first laser generating unit 24 for forming a welding portion 113 by first welding the ends of the plurality of electrode tabs 11 while cutting the plurality of electrode tabs 11 by irradiating 241; and a first fixing jig 23 for fixing the plurality of electrode tabs 11 to each other, wherein the first laser generating unit 24 is formed when the ends of the plurality of electrode tabs 11 are first welded. , by irradiating a second laser 242 to the central portions of the plurality of electrode tabs 11 , the central portions of the plurality of electrode tabs 11 are secondarily welded.

When the plurality of electrode tabs 11 are in contact with each other, the first laser generating unit 24 irradiates a first laser 241 as shown in FIG. 8 to irradiate the plurality of electrode tabs along the cutting line C ( 11) is cut. At the same time, the first laser 241 first welds the ends of the plurality of electrode tabs 11 to form a welding portion 113 at the ends of the electrode tabs 11 ( S603 ).

As described above, conventionally, the cutter 33 is used to cut the electrode tab 11 , but in this case, the end of the electrode tab 11 cannot be directly welded. On the other hand, according to an embodiment of the present invention, since the electrode tab 11 is cut using the first laser 241 , the ends of the plurality of electrode tabs 11 are simultaneously cut while cutting the electrode tab 11 . First welding is possible. As a result, a portion that is not in close contact between the plurality of electrode tabs 11 may be minimized, thereby reducing the resistance of the electrode tabs 11 .

At this time, as shown in FIG. 8 , the first fixing jig 23 is provided to prevent the plurality of electrode tabs 11 from moving before the first welding while cutting the ends of the plurality of electrode tabs 11 . The plurality of electrode tabs 11 may be fixed on both sides. The first fixing jig 23 includes a first upper jig 231 for fixing the electrode tabs 11 from above; and a first lower jig 232 for fixing the electrode tabs 11 from below. In addition, the first laser generating unit 24 may perform primary welding by irradiating the first laser 241 to the outside of the first fixing jig 23 .

9 is a schematic diagram illustrating a state in which the first laser generating unit 24 welds the center of the electrode tab 11 according to an embodiment of the present invention.

When the ends of the plurality of electrode tabs 11 are first welded, the first laser generating unit 24 irradiates a second laser 242 to the center of the plurality of electrode tabs 11 , and the plurality of electrode tabs 11 . ) are secondarily welded to the center (S604). Then, a space between the plurality of electrode tabs 11 is temporarily melted, and the melted portion is solidified again and welded. As a result, the plurality of electrode tabs 11 may be firmly connected to each other. The secondary welding may be performed while the first laser generating unit 24 moves from the end of the electrode tab 11 toward the center of the electrode tab 11 while the electrode assembly 10 is fixed.

Not only when the ends of the plurality of electrode tabs 11 are cut, but also when the central portions of the plurality of electrode tabs 11 are welded, the plurality of electrode tabs 11 are still fixed with the first fixing jig 23 . desirable. However, when the entire first fixing jig 23 has a closed shape, the second laser 242 cannot weld the central portion of the electrode tab 11 . Therefore, according to another embodiment of the present invention, the first upper jig 231 of the first fixing jig 23 may have a first through hole 2311 penetrating therethrough. And, by irradiating the second laser 242 toward the first through hole 2311 of the first upper jig 231 by the first laser generating unit 24, the second laser 242 is formed through the first through hole ( 2311), the plurality of electrode tabs 11 may be secondarily welded. On the other hand, if such a through hole is formed in the first lower jig 232 , since the plurality of electrode tabs 11 cannot be firmly fixed, there is a problem in that the electrode tabs 11 move. Therefore, it is preferable that the first through hole 2311 is formed only in the first upper jig 231 .

In order for the central portions of the plurality of electrode tabs 11 to be uniformly connected to each other, the first laser generator 24 moves the central portions of the plurality of electrode tabs 11 at a constant speed while maintaining the second laser 242 at a constant speed. can be thoroughly investigated. Since the second laser 242 may be irradiated through the first through-hole 2311 of the first upper jig 231 , the first laser generating unit 24 is disposed in the first through-hole 2311 . It is preferable to move only within the corresponding area.

As the area in which the first laser generator 24 moves is increased, the area to which the plurality of electrode tabs 11 are in close contact is also increased. Accordingly, in order to increase the area in which the first laser generating unit 24 moves, it is preferable to increase the area of the first through hole 2311 of the first upper jig 231 . However, if the area of the first through-hole 2311 is excessively wide, the first fixing jig 23 cannot firmly fix the plurality of electrode tabs 11, so there is a problem in that the electrode tabs 11 move. . On the other hand, if the area of the first through hole 2311 is excessively narrow, the area of the central portion of the electrode tab 11 that the first laser generating unit 24 can weld with the second laser 242 is also narrowed. , the resistance may not decrease. Therefore, the area of the first through-hole 2311 should be large enough to allow the electrode tabs 11 to be firmly attached and the first fixing jig 23 to firmly fix the plurality of electrode tabs 11 at the same time. desirable.

Meanwhile, the first laser 241 and the second laser 242 are both emitted from the first laser generator 24 , but may have different outputs. In particular, since the first laser 241 is used to cut the ends of the electrode tabs 11 , it can have a relatively high output, while the second laser 242 cuts the center of the electrode tabs 11 from each other. Since it is used for welding, it can have a relatively low output.

LASER is stimulated emission, that is, when light with a specific wavelength is incident on electrons in an excited state (excited state) and induces conversion to a ground state (ground state), the emitted light is amplified. . Since these lasers are amplified lights having the same wavelength, they have a monochromatic color, go straight in a specific direction, and have high energy.

Since a laser is also a kind of light, if the frequency of the laser changes, the wavelength changes and the color of the laser may also change. The laser according to an embodiment of the present invention includes various types of lasers, such as an IR laser having a wavelength in the infrared region of 800 nm or more, and a blue laser having a wavelength in the blue light region of 400 to 500 nm. Recently, a laser having a pulse width of nanoseconds (ns) and even picoseconds (ps) has been developed by significantly increasing the frequency of the laser. In this case, the wavelength of the laser is quite short, and the laser may not be visually visible.

In general, the factors that determine the output of a laser are frequency and pulse energy. Even if the frequency is constant, if the amplification amount of the laser increases, the pulse energy may also increase to increase the output. may increase. As described above, since the first laser 241 has a relatively higher output than the second laser 242, if the frequencies of the first laser 241 and the second laser 242 are the same, the The pulse energy of the first laser 241 may be higher than the pulse energy of the second laser 242 . On the other hand, if the pulse energy of the first laser 241 and the second laser 242 are the same, the frequency of the first laser 241 may be higher than that of the second laser 242 . However, it is easy to adjust the output by adjusting the amount of amplification because the adjustment range is limited in controlling the output by adjusting the frequency with a general laser equipment. That is, the first laser 241 and the second laser 242 may be emitted by controlling the output by adjusting the amplification amount of the first laser generating unit 24 .

On the other hand, when the first laser 241 or the second laser 242 is irradiated to the electrode tab 11 , a wavelength of high heat and high energy is applied to the electrode tab 11 , so that a lot of dust such as spatters or fumes is generated. may occur and scatter. Therefore, it is preferable to provide a dust collector for collecting dust. Although the dust collector may be separately installed around the electrode tab 11, according to an embodiment of the present invention, the first fixing jig 23 includes a suction unit (not shown) for sucking such dust, and Dust may be discharged to the outside by the suction unit. In particular, the suction unit may be installed on the first upper jig 231 in the first fixing jig 23 , and when installed on the outer surface of the first upper jig 231 , the first laser 241 is first welded. It is possible to suck the dust generated during the secondary welding by the second laser 242 when it is installed on the inner surface of the first upper jig 231 .

Also, when the first laser 241 or the second laser 242 is irradiated to the electrode tab 11 , the electrode tab 11 may be oxidized by reacting with surrounding oxygen. Accordingly, according to an embodiment of the present invention, the first fixing jig 23 may include a spraying unit (not shown) for spraying an inert gas toward the electrode tab 11 . In particular, the injection unit may be installed in the first upper jig 231 in the first fixing jig 23 , and when installed on the outer surface of the first upper jig 231 , the first laser 241 is inactive when the first welding is performed. Gas can be sprayed, and when installed on the inner surface of the first upper jig 231 , the inert gas can be sprayed when the second laser 242 performs secondary welding. This inert gas is preferably not reacting with the electrode tab 11 because of its low reactivity while blocking the surrounding oxygen, in particular nitrogen (N ₂ ), helium (He) or argon (Ar). have.

10 is a schematic diagram illustrating a state in which the second laser generator 26 welds the electrode tab 11 and the electrode lead 12 to each other according to an embodiment of the present invention.

In the electrode tab welding apparatus according to an embodiment of the present invention, as shown in FIG. 10 , when an electrode lead 12 is seated on one surface of the plurality of electrode tabs 11 , the electrode tab 11 and the electrode A second laser generator 26 , which irradiates the lead 12 with a third laser 261 to thirdly weld the electrode tab 11 and the electrode lead 12 , may be further included.

When the welding of the plurality of electrode tabs 11 is completed, as shown in FIG. 10 , the electrode lead 12 is seated on one surface of the plurality of electrode tabs 11 . In addition, the second laser generator 26 irradiates a third laser 261 to the electrode tab 11 and the electrode lead 12 , thereby tertiarily irradiating the electrode tab 11 and the electrode lead 12 . Welding (S605). Then, the gap between the electrode tab 11 and the electrode lead 12 is temporarily melted, and the melted portion is solidified again and welded. In particular, when all of the positive electrode tabs 111 are connected to each other, one end of the positive electrode lead 121 is thirdly welded to one surface of the positive electrode tab 111 with a third laser 261, and when the negative electrode tabs 112 are connected to each other, One end of the negative electrode lead 122 is thirdly welded to one surface of the negative electrode tab 112 by a third laser 261 . Accordingly, the electrode tab 11 and the electrode lead 12 may be firmly connected to each other.

At this time, as shown in FIG. 10 , when the electrode lead 12 is seated on one surface of the electrode tab 11 before the third welding of the electrode tab 11 and the electrode lead 12 , the electrode tab ( 11) and the second fixing jig 25 may fix the electrode tab 11 and the electrode lead 12 to each other in order to prevent the electrode lead 12 from moving. The second fixing jig 25 includes a second upper jig 251 for fixing the electrode tab 11 and the electrode lead 12 from above; and a second lower jig 252 for fixing the electrode tab 11 and the electrode lead 12 from below.

When the entire second fixing jig 25 has a closed shape, the third laser 261 cannot weld the electrode tab 11 and the electrode lead 12 together. Therefore, according to another embodiment of the present invention, the second upper jig 251 of the second fixing jig 25 may have a second through hole 2511 penetrating therethrough. And, by irradiating the third laser 261 toward the second through hole 2511 of the second upper jig 251 by the second laser generating unit 26, the third laser 261 is formed through the second through hole ( 2511), the electrode tab 11 and the electrode lead 12 may be thirdly welded.

The process of connecting the plurality of electrode tabs 11 to each other and the process of connecting the electrode tabs 11 and the electrode lead 12 to each other may be performed in different process lines. In this case, the first laser generating unit 24 and the second laser generating unit 26 may have different configurations, and the first fixing jig 23 and the second fixing jig 25 may also have different configurations. However, the process of connecting the plurality of electrode tabs 11 to each other and the process of connecting the electrode tabs 11 and the electrode leads 12 to each other may be performed on the same process line. In this case, the first laser generating unit 24 and the second laser generating unit 26 may have the same configuration, and the first fixing jig 23 and the second fixing jig 25 may also have the same configuration. Therefore, after the plurality of electrode tabs 11 are connected by secondary welding, when the first fixing jig 23 is removed and the electrode lead 12 is seated on one surface of the electrode tab 11, the first fixing jig ( 23 , the electrode tab 11 and the electrode lead 12 may be fixed again. In addition, the first laser generator 24 may irradiate the third laser 261 to perform third welding.

The first, second, and third lasers 241 , 242 , and 261 may have different frequencies or outputs. For example, the first and second lasers 241 and 242 may be blue lasers having a short wavelength, and the third laser 261 may be an IR laser having a long wavelength. In addition, the second laser 242 should perform secondary welding of all the plurality of electrode tabs 11 , but the third laser 261 is one surface of the electrode tab 11 located at the outermost side among the plurality of electrode tabs 11 . Since only the electrode lead 12 needs to be welded thirdly, it can have a relatively low output.

Those of ordinary skill in the art to which the present invention pertains will understand that the present invention may be embodied in other specific forms without changing the technical spirit or essential features thereof. Therefore, it should be understood that the embodiments described above are illustrative in all respects and not restrictive. The scope of the present invention is indicated by the following claims rather than the above detailed description, and various embodiments derived from the meaning and scope of the claims and their equivalent concepts should be construed as being included in the scope of the present invention.

1: secondary battery 10: electrode assembly
11: electrode tab 12: electrode lead
13: battery case 14: insulation part
21: electrode assembly fixing part 22: electrode tap press
23: first fixing jig 24: first laser generating unit
25: second fixing jig 26: second laser generating unit
31: horn 32: anvil
33: cutter 34: laser generating unit
111: positive tab 112: negative tab
113: weld 121: positive lead
122: negative lead 131: upper case
132: lower case 133: cup portion
134: sealing part 135: pouch film
231: first upper jig 232: first lower jig
241: first laser 242: second laser
251: second upper jig 252: second lower jig
261: third laser 1331: receiving space
2311: first through hole 2511: second through hole

Claims (18)

A first laser is irradiated to a plurality of electrode tabs protruding from an electrode assembly manufactured by laminating an electrode and a separator to cut the plurality of electrode tabs, and the ends of the plurality of electrode tabs are first welded to form a welded portion a first laser generator; and
Comprising a first fixing jig for fixing the plurality of electrode tabs to each other,
The first laser generating unit,
When the ends of the plurality of electrode tabs are firstly welded, an electrode tab welding apparatus for irradiating a second laser to the centers of the plurality of electrode tabs to secondarily weld the centers of the plurality of electrode tabs. According to claim 1,
The first fixing jig,
a first upper jig for fixing the electrode tabs from above; and
Electrode tab welding apparatus including a first lower jig for fixing the electrode tabs from below. 3. The method of claim 2,
The first upper jig,
An electrode tap welding apparatus in which a first through-hole penetrating through the interior is formed. 4. The method of claim 3,
The first laser generating unit,
An electrode tab welding apparatus for secondary welding a plurality of the electrode tabs by irradiating a second laser toward the first through hole. According to claim 1,
The first laser generating unit,
An electrode tap welding apparatus for primary welding by irradiating a first laser to the outside of the first fixing jig. According to claim 1,
The first laser and the second laser,
Electrode tap welding devices with different outputs. According to claim 1,
When the electrode leads are seated on one surface of the plurality of electrode tabs, by irradiating a third laser to the electrode tabs and the electrode leads, the electrode further comprising a second laser generator for tertiary welding the electrode tabs and the electrode leads tap welding device. 8. The method of claim 7,
When the electrode leads are seated on one surface of the plurality of electrode tabs, the electrode tab welding apparatus further comprising a second fixing jig for fixing the electrode tabs and the electrode leads to each other. 9. The method of claim 8,
The second fixing jig,
a second upper jig for fixing the electrode tab and the electrode lead from above; and
Electrode tab welding apparatus comprising a second lower jig for fixing the electrode tab and the electrode lead from below. 10. The method of claim 9,
The second upper jig,
An electrode tap welding apparatus in which a second through-hole penetrating the inside is formed. 11. The method of claim 10,
The second laser generating unit,
An electrode tab welding apparatus for welding the electrode tab and the electrode lead by irradiating a third laser toward the second through hole. According to claim 1,
The first fixing jig,
An electrode tap welding device including a suction unit for sucking dust generated by primary welding or secondary welding and discharging to the outside. According to claim 1,
The first fixing jig,
Electrode tab welding apparatus including a spraying unit for spraying an inert gas toward the electrode tab. manufacturing an electrode assembly by stacking an electrode and a separator;
forming a weld by first welding ends of the plurality of electrode tabs while cutting the plurality of electrode tabs by irradiating a first laser to the plurality of electrode tabs protruding from the electrode assembly; and
The electrode tab welding method comprising the step of irradiating a second laser to the first laser generator to the plurality of electrode tabs, and secondary welding the central portion of the plurality of electrode tabs. 15. The method of claim 14,
After manufacturing the electrode assembly and before the first welding step,
The electrode tab welding method further comprising the step of fixing the plurality of electrode tabs by a first fixing jig. 15. The method of claim 14,
After the second welding step,
seating the electrode leads on one surface of the plurality of electrode tabs; and
and irradiating a third laser to the electrode tab and the electrode lead by a second laser generator, and thirdly welding the electrode tab and the electrode lead. 17. The method of claim 16,
After the step of seating the electrode lead and before the third welding step,
The electrode tab welding method further comprising the step of fixing the electrode tab and the electrode lead to each other by a second fixing jig. 15. The method of claim 14,
The second welding step is
An electrode tab welding method in which the first laser generator moves while the electrode assembly is fixed.

Images