One]Cross Citation with Related Applications
[2]This application claims the benefit of priority based on Korean Patent Application No. 10-2019-0149920 dated November 20, 2019, and all contents disclosed in the documents of the Korean patent application are incorporated as a part of this specification.
[3]
technical field
[4]
The present invention relates to a method for manufacturing an electrode lead and a pouch-type secondary battery, and more particularly, by forming two-stage electrode leads to discharge the gas generated inside the battery case to the outside to ensure safety, It relates to a method of manufacturing an electrode lead for reducing the amount of heat generated by reducing the resistance between the electrode leads of the electrode lead, and to a pouch-type secondary battery including the same.
background
[5]
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 used in small products such as digital cameras, P-DVDs, MP3Ps, mobile phones, PDAs, Portable Game Devices, Power Tools, and E-bikes, but also in 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.
[6]
In order to manufacture the electrode assembly, a cathode, a separator, and a cathode are manufactured, and these are laminated. Specifically, 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. And when a separator is interposed between the manufactured positive electrode and the negative electrode and stacked, unit cells are formed, and the unit cells are stacked on each other, thereby forming an electrode assembly. And when the electrode assembly is accommodated in a specific case and an electrolyte is injected, a secondary battery is manufactured.
[7]
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.
[8]
The pouch-type battery case is manufactured by forming a cup portion by performing drawing molding on a pouch film having flexibility. 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.
[9]
Meanwhile, in the secondary battery, gas may be generated inside due to an internal short circuit, overcharging, overdischarging, or the like. This gas increases the internal pressure of the secondary battery, thereby causing problems such as weakening of bonding force between parts, damage to the case of the secondary battery, early operation of the protection circuit, deformation of the electrode, internal short circuit, and explosion. In the case of a can-type secondary battery, a protective member such as a CID filter and a safety vent is provided to physically block electrical connection when the pressure inside the case increases. However, in the case of a conventional pouch type secondary battery, such a protection member is not sufficiently provided.
DETAILED DESCRIPTION OF THE INVENTION
technical challenge
[10]
The problem to be solved by the present invention is that safety can be secured by discharging gas generated inside the battery case to the outside by forming two-stage electrode leads, and the amount of heat generated by reducing the resistance between the two-stage electrode leads An object of the present invention is to provide a method for manufacturing an electrode lead that lowers the temperature and to provide a pouch-type secondary battery including the same.
[11]
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.
means of solving the problem
[12]
An electrode lead manufacturing method according to an embodiment of the present invention for solving the above problems comprises: manufacturing a first electrode lead and a second electrode lead, respectively; and bonding the first electrode lead and the second electrode lead to each other to form a connection part, wherein the manufacturing of the first electrode lead comprises unwinding a first metal plate from a first metal reel. ; masking by attaching a first tape to a first connection area where the connection part is to be formed in the first metal plate; performing plating and surface treatment processes on the first metal plate; and removing the first tape, wherein the manufacturing of the second electrode lead includes: unwinding a second metal plate from a second metal reel; masking by attaching a second tape to a second connection area where the connection part is to be formed in the second metal plate; performing plating and surface treatment processes on the second metal plate; and removing the second tape.
[13]
In addition, one end of the first electrode lead may be connected to the electrode tab, and the first connection region may be formed at the other end of the first electrode lead.
[14]
In addition, the second connection region may be formed at one end of the second electrode lead.
[15]
In addition, the step of manufacturing the first electrode lead, after removing the first tape, further comprising cutting the first metal plate at regular intervals, manufacturing the second electrode lead may further include, after removing the second tape, cutting the second metal plate at regular intervals.
[16]
In addition, the manufacturing of the first electrode lead further includes the step of cutting the first metal plate at regular intervals before attaching and masking the first tape, and manufacturing the second electrode lead The performing may further include cutting the second metal plate at regular intervals before the masking by attaching the second tape.
[17]
In addition, when performing the plating and surface treatment process, a first film may be formed on the outer surface of the first metal plate, and a second film may be formed on the outer surface of the second metal plate.
[18]
In performing the plating and surface treatment process, the surface treatment may include at least one of chromate treatment, zirconia treatment, and titanium treatment.
[19]
According to an embodiment of the present invention for solving the above problems, a pouch-type secondary battery includes an electrode assembly including an electrode including a positive electrode and a negative electrode, and an electrode assembly in which a separator is stacked; a pouch-shaped battery case accommodating the electrode assembly; an electrode tab connected to the electrode and protruding from one side of the electrode assembly; a first electrode lead having one end connected to the electrode tab; a second electrode lead having one end connected to the other end of the first electrode lead and the other end protruding to the outside of the battery case; and a connection part connecting the first electrode lead and the second electrode lead by bonding them to each other, wherein the first electrode lead has a first film formed on an outer surface thereof, and the first connection part is formed in the first connection area where the connection part is formed. The first film is not formed, the second film is formed on the outer surface of the second electrode lead, and the second film is not formed in the second connection region where the connection part is formed.
[20]
In addition, the first film or the second film may be at least one of a chromate film, a zirconia film, and a titanium film.
[21]
In addition, an insulating part surrounding a portion of the first and second electrode leads and bonding the first and second electrode leads to the battery case may be further included.
[22]
In addition, an adhesive force between the first and second electrode leads and the connection part may be weaker than an adhesive force between the first and second electrode leads and the insulating part.
[23]
Also, the insulating part may surround a portion in which the first and second electrode leads are connected through the connection part.
[24]
In addition, the insulating part may be formed of at least one of a thermoplastic, thermosetting, and photocurable resin having electrical insulation properties.
[25]
In addition, the connection part may include a conductive material and a conductive polymer.
[26]
In addition, the connecting portion may have a thickness of 1 to 500 μm.
[27]
Other specific details of the invention are included in the detailed description and drawings.
Effects of the Invention
[28]
According to the embodiments of the present invention, there are at least the following effects.
[29]
By providing a plurality of electrode leads to form two-stage electrode leads, even when gas is generated inside the battery case and internal pressure increases, the gas can be discharged to the outside to ensure safety.
[30]
In addition, even when plating and surface treatment are performed on the first electrode lead and the second electrode lead, a coating film is not formed on the first and second connection regions that are connected to each other through the connection part, so that resistance can be reduced.
[31]
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.
Brief description of the drawing
[32]
1 is an assembly view of a secondary battery according to an embodiment of the present invention.
[33]
2 is a perspective view of a secondary battery according to an embodiment of the present invention.
[34]
3 is a perspective view illustrating an expanded volume of a pouch-type secondary battery according to an embodiment of the present invention.
[35]
4 is a portion of a cross-sectional view taken along line AA′ of FIG. 2 of a pouch-type secondary battery according to an embodiment of the present invention.
[36]
5 is a portion of a cross-sectional view taken along line AA′ of FIG. 2 in which the volume of a pouch-type secondary battery according to an embodiment of the present invention is expanded.
[37]
6 is a flowchart of a method for manufacturing a first electrode lead or a second electrode lead according to an embodiment of the present invention.
[38]
7 is a schematic diagram illustrating a state of attaching a tape to a metal plate unwound from a metal reel according to an embodiment of the present invention.
[39]
8 is a schematic view showing a state in which the tape is peeled from the metal plate unwound from the metal reel according to an embodiment of the present invention.
[40]
9 is a schematic diagram illustrating a state in which a first electrode lead and a second electrode lead are adhered according to an embodiment of the present invention.
[41]
10 is a schematic view showing a state in which the first electrode lead and the second electrode lead are adhered according to an embodiment of the present invention to complete the manufacture of the two-stage electrode lead.
[42]
11 is a flowchart of a method of manufacturing a first electrode lead or a second electrode lead according to another embodiment of the present invention.
Modes for carrying out the invention
[43]
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 can 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.
[44]
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 specifically defined.
[45]
The terminology used herein is for the purpose of describing the embodiments and is not intended to limit the present invention. In this specification, 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.
[46]
Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.
[47]
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.
[48]
As shown in FIG. 1 , the pouch-type secondary battery 1 according to an embodiment of the present invention includes an electrode assembly 10 formed by stacking electrodes such as a positive electrode and a negative electrode and a separator, and the electrode assembly 10 . Includes a pouch-type battery case 13 for accommodating therein.
[49]
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.
[50]
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 forms 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, a plasticizer, and the like in a state in which a solvent is added. The solvent is removed in a subsequent process.
[51]
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.
[52]
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 by spot welding or the like. A plurality of electrode leads 12 according to an embodiment of the present invention are provided to form two-stage electrode leads 12 . And, among the two-stage electrode leads 12 , the first electrode lead 123 (shown in FIG. 4 ) is connected to the electrode tab 11 of the electrode assembly 10 , and the second electrode lead 124 ( FIG. 4 ). shown in ) protrudes to the outside of the battery case (Battery Case, 13). A detailed description of the two-stage electrode lead 12 will be described later.
[53]
A part of the electrode lead 12 is surrounded by an insulating portion 14 . The insulating part 14 is located limitedly in the sealing part 134 to which the upper case 131 and the lower case 132 of the battery case 13 are thermally fused, so that 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 part 14, an insulating tape that is easy to attach to the electrode lead 12 and has a relatively thin thickness is often used. have.
[54]
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.
[55]
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 portion, and is electrically connected to the external terminal.
[56]
The battery case 13 is a pouch made of a soft material for accommodating 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 stretched 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 portion 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 accommodation space 1331 is covered from the top so as not to be separated to the outside of the . And the sealing part 134 is sealed to seal the accommodation space 1331 . At this time, 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 with one side connected to each other as shown in FIG.
[57]
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 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.
[58]
3 is a perspective view illustrating an expanded volume of the pouch-type secondary battery 1 according to an embodiment of the present invention.
[59]
In general, the pouch-type secondary battery 1 may generate an abnormally large amount of gas due to internal short circuit due to external impact of the electrode assembly 10, heat due to overcharging, overdischarging, etc., and electrolyte decomposition and thermal runaway phenomenon. Alternatively, when stored or stored at a high temperature, the high temperature may rapidly promote the electrochemical reaction of the electrolyte and the electrode active material to generate gas.
[60]
Meanwhile, in order to manufacture the pouch-type battery case 13 , the pouch film 135 having flexibility is drawn and molded using a punch or the like, and the cup part 133 is recessed in the lower case 132 . This drawing molding is performed by inserting the pouch film 135 into a press and applying pressure to the pouch film 135 with a punch to stretch the pouch film 135 . By stretching the pouch film 135 to form the cup portion 133 as described above, the battery case 13 is manufactured. The pouch film 135 is a surface protection layer mainly made of a polymer such as nylon resin or polyethylene terephthalate (PET), and a gas barrier layer mainly made of an aluminum thin film (Al Foil) (Gas). It is formed by laminating a barrier layer) and a sealant layer mainly made of a polymer such as polypropylene (PP) or polyethylene (PE).
[61]
If gas is generated inside the battery case 13 , since all layers of the battery case 13 have flexibility, the generated gas increases the internal pressure of the secondary battery 1 , as shown in FIG. 3 . Similarly, the volume of the secondary battery 1 expands. In addition, problems such as weakening of the bonding force between parts, damage to the case of the secondary battery 1, early operation of the protection circuit, deformation of the electrode, internal short circuit, and explosion occur.
[62]
4 is a part of a cross-sectional view taken along line AA′ of FIG. 2 of the pouch-type secondary battery 1 according to an embodiment of the present invention.
[63]
When gas is generated inside the battery case 13, the internal pressure of the secondary battery 1 rises, weakening the bonding force between parts, damage to the case of the secondary battery 1, early operation of the protection circuit, deformation of the electrode, internal short circuit, It causes problems such as explosions.
[64]
To solve this problem, in the pouch-type secondary battery 1 according to an embodiment of the present invention, as shown in FIG. 4 , the electrode leads 12 are formed in two stages. That is, the electrode lead 12 includes a first electrode lead 123 connected to the electrode tab 11 of the electrode assembly 10 and a second electrode lead 124 protruding to the outside of the battery case 13 . . In addition, the other end of the first electrode lead 1230 and one end of the second electrode lead 1240 are connected to each other by bonding one surface to each other through the connecting portion 15 .
[65]
When the battery case 13 is normal, the first and second electrode leads 123 and 124 should be stably connected to each other, and when the battery case 13 is expanded, the first and second electrode leads 123 and 124 are connected to each other. It should be easily detached. Therefore, it is preferable that the first and second electrode leads 123 and 124 are positioned on different planes and have upper and lower surfaces connected to each other rather than being positioned on the same plane and connected to each other.
[66]
The connecting portion 15 for bonding the first electrode lead 123 and the second electrode lead 124 to each other is preferably very thin with a thickness of 1 to 500 μm. Therefore, even if the first electrode lead 123 and the second electrode lead 124 form a step, the step size may not be excessively large.
[67]
Meanwhile, as described above, a part of the electrode lead 12 is surrounded by the insulating portion 14 . And through the insulating portion 14, the electrode lead is adhered to the battery case. In the process of sealing the upper case 131 and the lower case 132 , the portion in contact with the electrode lead 12 has a relatively high pressure, so that the sealant layer of the battery case 13 is highly likely to be damaged. As described above, the sealant layer has insulation properties because it is in direct contact with the electrode assembly 10 . However, if the sealant layer is broken, electricity may flow to the battery case 13 through the electrode lead 12 . In particular, since the gas barrier layer of the battery case 13 is made of a metal such as aluminum, if the sealant layer is even a little damaged and the gas barrier layer is exposed, electricity can easily flow through contact with the electrode lead 12 .
[68]
Accordingly, the insulating portion 14 is made of a non-conductive material that does not conduct electricity well. In addition, the insulating portion 14 has high mechanical strength and heat resistance. Accordingly, the insulating part 14 may include, for example, a polyolefin-based resin such as polypropylene (PP) or polyethylene (PE). In particular, polypropylene (PP) has excellent mechanical properties such as tensile strength, rigidity, surface hardness, abrasion resistance, heat resistance, and chemical properties such as corrosion resistance, and is mainly used for manufacturing the insulating part 14 . Further, in order to improve the adhesive force of the insulating portion 14, acid-treated polypropylene may be included. For example, acid-treated polypropylene and normal polypropylene may be mixed, polyethylene may be further mixed, and only acid-treated polypropylene may be included. Here, the acid-treated polypropylene may be MAH PP (maleic anhydride polypropylene).
[69]
Therefore, when the upper case 131 and the lower case 132 are thermally fused, the insulating portion 14 maintains its shape, so that even if the sealant layer is partially damaged and the gas barrier layer is exposed, the electrode lead 12 and the gas barrier layer cut off contact As a result, electricity generated from the electrode assembly 10 is prevented from flowing to the battery case 13 through the electrode lead 12 . And the insulating part 14 has high adhesiveness. Accordingly, the upper case 131 and the lower case 132 of the battery case 13 are limitedly positioned in the sealing portion to be thermally fused, and the electrode lead 12 is adhered to the battery case 13 . The insulating part 14 is a polymer resin, and may be made of at least one of a thermoplastic, thermosetting, and photocurable resin having electrical insulation properties. In general, as the insulating part 14, an insulating tape that is easy to attach to the electrode lead 12 and has a relatively thin thickness is often used. have.
[70]
As shown in FIG. 4 , the insulating part 14 surrounds all of the first electrode lead 123 , the connection part 15 , and the second electrode lead 124 . If the first electrode lead 123 or the connection part 15 is not surrounded, even if the battery case 13 expands, a repulsive force cannot be applied to the first electrode lead 123 and the second electrode lead 124 . to be. A detailed description of the repulsive force will be described later.
[71]
FIG. 5 is a portion of a cross-sectional view taken along line AA′ of FIG. 2 showing an expanded volume of the pouch-type secondary battery 1 according to an embodiment of the present invention.
[72]
As described above, if the pressure inside the pouch-type battery case 13 increases, the volume of the pouch-type secondary battery 1 expands. Accordingly, as shown in FIG. 5 , the outer wall of the battery case 13 moves toward the outside. At this time, the upper wall and the lower wall of the outer wall of the battery case 13 have a large area and are not sealed, so that the ductility is higher. Accordingly, the upper wall of the battery case 13 moves upward, and the lower wall moves downward. Meanwhile, while the outer wall of the battery case 13 moves toward the outside, a repulsive force is applied to the first electrode lead 123 and the second electrode lead 124 connected through the insulating part 14 . Therefore, as the internal pressure of the battery case 13 gradually increases, the force to move the outer wall of the battery case 13 increases, and the magnitude of the repulsive force applied to the first electrode lead 123 and the second electrode lead 124 . also increases further.
[73]
When the magnitude of the repulsive force is greater than the adhesive force between the first electrode lead 123 and the second electrode lead 124 , the first electrode lead 123 and the second electrode lead 124 as shown in FIG. 9 . is eventually desorbed. Therefore, the electrical connection is physically cut off, so that electricity can no longer flow. Here, desorption means that the adsorbed or adhered thing falls off. However, in this case, the adhesive force between the first electrode lead 123 and the second electrode lead 124 and the connection part 15 is increased between the first electrode lead 123 and the second electrode lead 124 and the insulating part 14 . weaker than adhesion. Therefore, when a repulsive force is applied to the first electrode lead 123 and the second electrode lead 124 , the adhesive force between the first electrode lead 123 and the second electrode lead 124 and the insulating part 14 is maintained, The sealing of the battery case 13 is maintained, and the first electrode lead 123 and the second electrode lead 124 are detached from each other.
[74]
On the other hand, when manufacturing such an electrode lead 12, plating and surface treatment are performed on a metal plate so that the insulating part 14 is easily attached to the electrode lead 12 later to form a film on the outer surface. . However, if plating and surface treatment are performed before bonding the first electrode lead 123 and the second electrode lead 124 to each other, after bonding the first electrode lead 123 and the second electrode lead 124 to each other, the coatings formed on the outer surface are bonded to each other, so the resistance increases on the bonding surface. may occur. Conversely, if plating and surface treatment are performed after the first electrode lead 123 and the second electrode lead 124 are adhered to each other, the first electrode lead 123 and the second electrode lead 124 are separated from each other. There may be a problem in that the connecting part 15 is damaged.
[75]
6 is a flowchart of a method of manufacturing the first electrode lead 123 or the second electrode lead 124 according to an embodiment of the present invention.
[76]
According to an embodiment of the present invention, even when plating and surface treatment are performed on the first electrode lead 123 and the second electrode lead 124 , the first and second connection regions are connected to each other through the connection part 15 . A film is not formed on (1231, 1241), so that resistance can be reduced.
[77]
To this end, the electrode lead 12 manufacturing method according to an embodiment of the present invention comprises the steps of manufacturing the first electrode lead 123 and the second electrode lead 124, respectively; and bonding the first electrode lead 123 and the second electrode lead 124 to each other to form a connection part, wherein the manufacturing of the first electrode lead 123 includes: a first metal reel ( unwinding the first metal plate 211 in 21); masking by attaching a first tape 31 to the first connection area 1231 where the connection part is to be formed in the first metal plate 211; performing plating and surface treatment processes on the first metal plate 211; and removing the first tape 31 , wherein the manufacturing of the second electrode lead 124 includes unwinding the second metal plate 221 from the second metal reel 22 . ; masking by attaching a second tape (32) to the second connection region (1241) where the connection portion is to be formed in the second metal plate (221); performing plating and surface treatment processes on the second metal plate 221; and removing the second tape (32).
[78]
In addition, the pouch-type secondary battery 1 according to an embodiment of the present invention including the electrode lead 12 manufactured by this method includes an electrode including a positive electrode and a negative electrode, and an electrode assembly 10 in which a separator is laminated; a pouch-shaped battery case accommodating the electrode assembly 10; an electrode tab 11 connected to the electrode and protruding from one side of the electrode assembly 10; a first electrode lead 123 having one end connected to the electrode tab 11; a second electrode lead 124 having one end connected to the other end of the first electrode lead 123 and the other end protruding to the outside of the battery case; and a connection part connecting the first electrode lead 123 and the second electrode lead 124 by bonding them to each other, wherein the first electrode lead 123 has a first film 1232 formed on an outer surface thereof, , the first film 1232 is not formed in the first connection region 1231 where the connection part is formed, and the second electrode lead 124 has a second film 1242 formed on an outer surface thereof, and the connection part The second film 1242 is not formed in the second connection region 1241 in which is formed.
[79]
Hereinafter, each step shown in the flowchart of FIG. 6 will be described in detail with reference to FIGS. 7 to 10 .
[80]
7 is a schematic diagram illustrating a state in which the tapes 31 and 32 are attached to the metal plates 211 and 221 unwound from the metal reels 21 and 22 according to an embodiment of the present invention.
[81]
In order to manufacture the two-stage electrode lead 12 , first, the first electrode lead 123 and the second electrode lead 124 are separately manufactured. Then, the first electrode lead 123 and the second electrode lead 124 are adhered to each other to form a connection portion.
[82]
In order to manufacture the first electrode lead 123 , first, the first metal plate 211 is unwound from the first metal reel 21 ( S601 ). The first metal reel 21 is a reel on which the first metal plate 211 is wound, and the first metal plate is unwound from the first metal reel 21 at a constant speed. And this first metal plate 211 becomes a raw material of the first electrode lead 123 .
[83]
When the first metal plate 211 is unwound, the masking is performed by attaching the first tape 31 to the first connection area 1231 ( S602 ). As described above, one end of the first electrode lead 123 is connected to the electrode tab 11 , and the other end is connected to one end of the second electrode lead 124 . Accordingly, the first connection region 1231 is formed at the other end of the first electrode lead 123 to be connected to the second electrode lead 124 later. And, as shown in FIG. 7 , in the first metal plate 211 , the first connection region 1231 is preferably formed to be elongated in the longitudinal direction along one edge of the first metal plate 211 . Thereby, one first tape 31 can be attached to the first connection area 1231 at a time, without the need to cut the first tape 31 into several pieces and attach them multiple times.
[84]
When the masking process of the first tape 31 is completed, surface treatment such as plating, oxidation, and film treatment is performed on the first metal plate 211 ( S603 ). If the electrode lead 12 is the positive electrode lead 121 , as described above, the metal plates 211 and 221 may be made of the same aluminum (Al) material as the positive electrode current collector. And if the electrode lead 12 is the negative lead 122 , the metal plates 211 and 221 may be made of the same copper (Cu) material as the negative electrode current collector. A plating process is performed on the metal plates 211 and 221 with a metal such as nickel (Ni). The plating process is not limited to electroplating, electroless plating, etc., and may be performed in various ways.
[85]
When the plating process is completed, surface treatment is performed to prevent oxidation of the metal plates 211 and 221 and improve adhesion to the insulating part 14 . The surface treatment may be a chromate treatment using chromium. Chromate treatment is a type of chemical conversion coating treatment, in which an insoluble chromate (chromate) film containing a chromium component is formed thinly on the surface of a metal. To this end, the metal plates 211 and 221 are immersed in an aqueous solution containing chromium ions. Then, the chromium ions are oxidized to form insoluble chromium oxide on the outer surfaces of the metal plates 211 and 221 to form a chromate film. Here, the chromium ion is not limited to, such as a hexavalent ion or a trivalent ion, and may be various types of ions. In addition, the aqueous solution containing chromium ions is not limited, and various substances such as chromic anhydride, chromium nitrate, chromium sulfate, chromium acetate and chromium chloride may be used.
[86]
Meanwhile, the surface treatment may be a non-chromate treatment using a material other than chromium. Here, the material other than chromium may be, for example, zirconium. If the zirconia treatment using zirconium is performed, the metal plates 211 and 221 are immersed in an aqueous solution containing zirconium ions. Then, the zirconium ions are oxidized to form zirconium oxide on the outer surfaces of the metal plates 211 and 221 to form a zirconia film. The non-chromate treatment is not limited thereto, and may include titanium treatment using titanium. That is, the surface treatment of the metal plates 211 and 221 is not limited and various methods may be used.
[87]
8 is a schematic diagram illustrating a state in which the tapes 31 and 32 are peeled from the metal plates 211 and 221 unwound from the metal reels 21 and 22 according to an embodiment of the present invention.
[88]
When the surface treatment of the first metal plate 211 is completed, as shown in FIG. 8 , the masked first tape 31 is peeled and removed ( S604 ). As described above, when the surface treatment of the first metal plate 211 is completed, the first film 1232 is formed on the outer surface of the first metal plate 211 , but the first film 1232 is masked with the first tape 31 . The first film 1232 is not formed on the outer surface of only the first connection region 1231 . On the other hand, the first tape 31 should not be corroded or deformed during surface treatment. Therefore, it is preferable to be made of a material having excellent corrosion resistance and abrasion resistance.
[89]
Thereafter, the first metal plate 211 is cut at regular intervals (S605). Thereby, the manufacturing of the first electrode lead 123 may be completed.
[90]
Meanwhile, in order to manufacture the second electrode lead 124 , the same method as the method for manufacturing the first electrode lead 123 is performed. Hereinafter, the content overlapping with the above-described content is omitted, but this is for convenience of description and is not intended to limit the scope of rights.
[91]
Specifically, first, the second metal plate 221 is unwound from the second metal reel 22 ( S601 ). Then, when the second metal plate 221 is unwound, a second tape 32 is attached to the second connection area 1241 to perform masking (S602). As described above, one end of the second electrode lead 124 is connected to the other end of the first electrode lead 123 , and the other end protrudes to the outside of the battery case. Accordingly, the second connection region 1241 is formed at one end of the second electrode lead 124 to be connected to the first electrode lead 123 later. And, as shown in FIG. 7 , in the second metal plate 221 , the second connection region 1241 is preferably formed to be elongated in the longitudinal direction along one edge of the second metal plate 221 .
[92]
When the masking process of the second tape 32 is completed, surface treatment such as plating, oxidation, and film treatment is performed on the second metal plate 221 ( S603 ). When the surface treatment of the second metal plate 221 is completed, as shown in FIG. 8 , the masked second tape 32 is peeled and removed ( S604 ). As described above, when the surface treatment of the second metal plate 221 is completed, the second film 1242 is formed on the outer surface of the second metal plate 221 , but the second film 1242 is masked with the second tape 32 . The second film 1242 is not formed on the outer surface only in the second connection region 1241 . On the other hand, the second tape 32 should not be corroded or deformed during surface treatment. Therefore, it is preferable to be made of a material having excellent corrosion resistance and abrasion resistance.
[93]
Thereafter, the second metal plate 221 is cut at regular intervals (S605). Thereby, the manufacture of the second electrode lead 124 may be completed.
[94]
It is preferable that both the first electrode lead 123 and the second electrode lead 124 have a rectangular shape. And in order to be easily adhered to each other later, it is preferable that the widths are equal to each other. Accordingly, a predetermined interval for cutting the first metal plate 211 may be the same as a predetermined interval for cutting the second metal plate 221 .
[95]
When cutting the metal plates 211 and 221, a press apparatus may be used and a laser may be used. That is, in order to manufacture the first electrode lead 123 and the second electrode lead 124 , the metal plates 211 and 221 may be cut in various ways without being limited thereto.
[96]
9 is a schematic diagram illustrating a state in which the first electrode lead 123 and the second electrode lead 124 are adhered according to an embodiment of the present invention, and FIG. 10 is a first electrode lead according to an embodiment of the present invention. Reference numeral 123 and the second electrode lead 124 are adhered to each other to show a state in which the production of the two-stage electrode lead 12 is completed.
[97]
In at least one of the first connection area 1231 of one end of the manufactured first electrode lead 123 and the second connection area 1241 of the other end of the second electrode lead 124, as shown in FIG. 9 . An adhesive 151 is applied. Then, the first connection region 1231 and the second connection region 1241 are adhered to each other to form a lead laminate.
[98]
The adhesive 151 includes a conductive material. Thereby, electricity generated from the electrode assembly 10 can be easily discharged to the outside. To this end, the adhesive 151 is preferably formed by mixing a conductive material and a polymer.
[99]
The conductive material may include graphite such as natural or artificial; carbon black, such as carbon black, acetylene black, Ketjen black, channel black, furnace black, lamp black, and summer black; conductive fibers such as carbon fibers or metal fibers; metal powders such as carbon fluoride, aluminum, nickel, gold, silver, and copper powder; Powder having a core/shell structure coated with a different type of metal on one type of metal; conductive whiskers such as zinc oxide and potassium titanate; conductive metal oxides such as titanium oxide; and at least one of a conductive material such as a polyphenylene derivative, particularly preferably silver. The amount of the conductive material included in the adhesive 151 is preferably 70 to 80 wt%.
[100]
Polymer is a thermosetting polymer resin, such as epoxy resin, acrylic resin, EPDM (Ethylene Propylene Diene Monomer) resin, CPE (Chlorinated Polyethylene) resin, silicone, polyurethane, urea resin, melamine resin, phenolic resin and unsaturated ester resin, polypropylene (Polypropylene). ), polyethylene (Polyethylene), polyimide (Polyimide), and includes at least one of polyamide (Polyamide), in particular, it is most preferable to include an epoxy or an acrylic resin. The amount of the polymer included in the adhesive 151 is preferably 20 to 30 wt%.
[101]
After the adhesive 151 is applied, when heat is applied to the lead laminate, the adhesive 151 is dried and cured to form a connection portion 15, and the connection portion 15 includes a conductive material and a conductive polymer. . Therefore, as shown in FIG. 10 , the manufacturing of the two-stage electrode lead 12 in which the first electrode lead 123 and the second electrode lead 124 are connected to each other is completed.
[102]
11 is a flowchart of a method of manufacturing the first electrode lead 123 or the second electrode lead 124 according to another embodiment of the present invention.
[103]
According to an embodiment of the present invention, in order to manufacture the first electrode lead 123 or the second electrode lead 124, the step of cutting the first metal plate 211 or the second metal plate 221 is, This was performed after the first tape 31 or the second tape 32 was peeled off and removed. Thereby, since the metal plates 211 and 221 are not cut into several pieces but are continuously formed into one, there is no need to cut the tapes 31 and 32 into several pieces and attach them several times, but one tape 31, 32 ) may be attached to the first and second connection regions 1231 and 1241 at once.
[104]
According to another embodiment of the present invention, in order to manufacture the first electrode lead 123 or the second electrode lead 124, the step of cutting the first metal plate 211 or the second metal plate 221 is, It is performed before the step of attaching and masking the first tape 31 or the second tape 32 . That is, when the first metal plate 211 or the second metal plate 221 is unwound from the first metal reel 21 or the second metal reel 22 , the first metal plate 211 or the second metal plate ( 221) is cut into several pieces. Specifically, first, the metal plates 211 and 221 are unwound from the metal reels 21 and 22 ( S1101 ). When the metal plates 211 and 221 are unwound, the metal plates 211 and 221 are cut at regular intervals (S1102). Thereafter, masking is performed by attaching the first or second tapes 31 and 32 to the first or second connection regions 1231 and 1241 ( S1103 ). When the masking process of the tapes 31 and 32 is completed, surface treatment such as plating, oxidation, and film treatment is performed on the metal plates 211 and 221 ( S1104 ). When the surface treatment of the metal plates 211 and 221 is completed, the masked tapes 31 and 32 are peeled and removed (S1105). Thereby, manufacturing of the first electrode lead 123 or the second electrode lead 124 may be completed.
[105]
When the above method is performed, since the first tape 31 or the second tape 32 is cut into several pieces, the size of the first tape 31 or the second tape 32 is reduced. Accordingly, it can be accurately attached to the first connection area 1231 or the second connection area 1241 to be attached. In addition, since the masking process can be performed even after the metal plates 211 and 221 have already been cut, the process sequence can be flexibly changed.
[106]
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.

WE CLAIMS

manufacturing a first electrode lead and a second electrode lead, respectively; and bonding the first electrode lead and the second electrode lead to each other to form a connection part, wherein the manufacturing of the first electrode lead comprises unwinding a first metal plate from a first metal reel. ; masking by attaching a first tape to a first connection area where the connection part is to be formed in the first metal plate; performing plating and surface treatment processes on the first metal plate; and removing the first tape, wherein the manufacturing of the second electrode lead includes: unwinding a second metal plate from a second metal reel; masking by attaching a second tape to a second connection area where the connection part is to be formed in the second metal plate; performing plating and surface treatment processes on the second metal plate; and removing the second tape.
[Claim 2]
The method of claim 1 , wherein one end of the first electrode lead is connected to the electrode tab, and the first connection region is formed at the other end of the first electrode lead.
[Claim 3]
The method of claim 2 , wherein the second connection region is formed at one end of the second electrode lead.
[Claim 4]
According to claim 1, wherein the manufacturing of the first electrode lead, after removing the first tape, further comprising the step of cutting the first metal plate at regular intervals, the second electrode lead The manufacturing method further includes, after removing the second tape, cutting the second metal plate at regular intervals.
[Claim 5]
The method of claim 1 , wherein the manufacturing of the first electrode lead further comprises: cutting the first metal plate at regular intervals before the masking by attaching the first tape; The manufacturing of the electrode lead may further include cutting the second metal plate at regular intervals before the masking by attaching the second tape.
[Claim 6]
According to claim 1, When performing the step of performing the plating and surface treatment process, a first film is formed on the outer surface of the first metal plate, and the second film is formed on the outer surface of the second metal plate electrode lead manufacturing Way.
[Claim 7]
The method of claim 1 , wherein in the performing of the plating and surface treatment processes, the surface treatment comprises at least one of chromate treatment, zirconia treatment, and titanium treatment.
[Claim 8]
an electrode assembly including an anode and a cathode, and a separator stacked thereon; a pouch-shaped battery case accommodating the electrode assembly; an electrode tab connected to the electrode and protruding from one side of the electrode assembly; a first electrode lead having one end connected to the electrode tab; a second electrode lead having one end connected to the other end of the first electrode lead and the other end protruding to the outside of the battery case; and a connection part connecting the first electrode lead and the second electrode lead by bonding them to each other, wherein the first electrode lead has a first film formed on an outer surface thereof, and the first connection part is formed in the first connection area where the connection part is formed. A pouch-type secondary battery in which a first film is not formed, a second film is formed on an outer surface of the second electrode lead, and the second film is not formed in a second connection region where the connection part is formed.
[Claim 9]
The pouch-type secondary battery of claim 8 , wherein the first or second film is at least one of a chromate film, a zirconia film, and a titanium film.
[Claim 10]
The pouch-type secondary battery of claim 8 , further comprising an insulating part surrounding a portion of the first and second electrode leads and bonding the first and second electrode leads to the battery case.
[Claim 11]
The pouch-type secondary battery of claim 10 , wherein an adhesive force between the first and second electrode leads and the connection part is weaker than an adhesive force between the first and second electrode leads and the insulating part.
[Claim 12]
The pouch-type secondary battery of claim 10 , wherein the insulating part surrounds a portion where the first and second electrode leads are connected through the connection part.
[Claim 13]
The pouch type secondary battery of claim 10 , wherein the insulating part is formed of at least one of a thermoplastic, thermosetting, and photocurable resin having electrical insulation properties.
[Claim 14]
The pouch-type secondary battery of claim 8 , wherein the connection part includes a conductive material and a conductive polymer.
[Claim 15]
The pouch-type secondary battery according to claim 8, wherein the connecting portion has a thickness of 1 to 500 μm.