Specification
Title of the invention: electrode assembly and manufacturing method of the electrode assembly
Technical field
[One]
This application claims the benefit of priority based on Korean Patent Application No. 10-2018-0094484 filed on August 13, 2018, and all contents disclosed in the documents of the Korean patent application are included as part of this specification.
[2]
The present invention relates to an electrode assembly and a method of manufacturing the electrode assembly, and more particularly, to an electrode assembly capable of improving current density variation inside a cell, and a method of manufacturing the electrode assembly.
Background
[3]
Batteries that generate electrical energy through physical reactions or chemical reactions of substances to supply power to the outside cannot obtain AC power supplied to buildings, depending on the living environment surrounded by various electric and electronic devices. It is used when a DC power supply is required.
[4]
Among such batteries, a primary battery and a secondary battery, which are chemical batteries using a chemical reaction, are commonly used, and the primary batteries are commonly referred to as dry cells and are consumable batteries. In addition, a secondary battery is a rechargeable battery manufactured using a material in which the oxidation-reduction process between the current and the material can be repeated many times. When a reduction reaction is performed on the material by the current, the power is charged and the oxidation reaction on the material is performed. When performed, the power is discharged, and electricity is generated as such charge-discharge is repeatedly performed.
[5]
Meanwhile, among secondary batteries, lithium-ion batteries are coated with an active material to a predetermined thickness on the positive conductive foil and the negative conductive foil, respectively, and a separator is interposed between the two conductive foils to form a jelly roll or a cylinder several times. The electrode assembly manufactured by winding is stored in a cylindrical or rectangular can, pouch, etc. and is manufactured by sealing it.
[6]
As such lithium-ion batteries are commercialized and widely used, applications such as automobiles, electronic devices, and power tools are also diversifying.
[7]
Accordingly, the output of secondary batteries is also emerging as an important spec.
[8]
Currently, polymer cells are connected to the tab by stacking the anode/separator/cathode/separator sequentially to connect the cathode to the cathode and the anode to the anode.
[9]
Korean Patent Application Publication No. 10-2008-0038465 discloses a battery cell having excellent structural safety and insulation resistance.
[10]
Conventional pouch batteries use positive/negative terminals for one terminal in both unidirectional and both directions.
[11]
However, such a conventional pouch battery has a problem in that the size of the tab, which is an electron entrance, is formed smaller than the electrode area that gradually increases.
[12]
Therefore, there is a problem in that there are few paths through which the current moves, so that the current density inside the electrode is different, so that there may be a variation in the current density inside the cell.
Detailed description of the invention
Technical challenge
[13]
Accordingly, the present invention has been devised to solve the above problems, and an object of the present invention is to provide an electrode assembly and a method of manufacturing an electrode assembly capable of securing an electron movement path inside the electrode assembly.
Means of solving the task
[14]
In the electrode assembly according to an embodiment of the present invention, in a single electrode assembly in which a plurality of cathodes and anodes are repeatedly stacked to cross each other, and a separator is stacked between a plurality of cathodes and anodes, a plurality of the electrode assemblies A negative electrode tab formed extending from the negative electrode, a positive electrode busbar that is spaced apart from the negative electrode tab part at one end of the electrode assembly and electrically connects the plurality of positive electrodes to each other, And a cathode busbar extending from an anode and spaced apart from the anode tab at the other end of the electrode assembly, and electrically connecting the plurality of cathodes to each other.
[15]
The positive busbar and the negative busbar may be formed at positions symmetrical to each other around a central portion of the electrode assembly.
[16]
Each of the anode busbar and the cathode busbar may be formed in plural.
[17]
The positive busbar may be formed of an electrode current collector extending from the positive electrode, and the negative busbar may be formed of an electrode current collector extending from the negative electrode.
[18]
It is installed between the positive busbar and the negative electrode to insulate between the positive busbar and the negative electrode of the electrode assembly, or installed between the negative busbar and the positive electrode to insulate between the negative busbar and the positive electrode of the electrode assembly. It may include an insulating member.
[19]
In the method of manufacturing an electrode assembly according to an embodiment of the present invention, a single electrode stack is formed by alternately stacking electrodes and a separator, and at one end, a cathode including a cathode extension portion, which is a longer portion than the anode and the separator, and the other A lamination step of forming an electrode stack by using an anode including an anode extension portion having a length longer than that of the cathode and the separator at the side end, and a cathode welding step of welding the plurality of cathode extension portions included in the plurality of cathodes to each other And an anode welding step of welding the plurality of anode extensions included in the plurality of anodes to each other.
[20]
In the laminating step, an anode having an anode tab portion formed at one end, a separator, and a cathode including a cathode extension portion at one end may be sequentially stacked.
[21]
When the cathode extension portions are welded to each other in the cathode welding step, portions of the cathode extension portions spaced apart from the anode tab portion may be welded.
[22]
In the laminating step, a cathode having a cathode tab portion formed at the other end, a separator, and an anode including an anode extension portion at the other end may be sequentially stacked.
[23]
In the anode welding step, when the anode extension portions are welded to each other, a portion of the anode extension portions spaced apart from the cathode tab portion may be welded.
[24]
In the cathode welding step and the anode welding step, the cathode extension part and the anode extension part may be welded by ultrasonic welding or thermal welding, respectively.
[25]
The cathode cutting step of cutting portions of the cathode extension portions that are not welded to each other may be further included.
[26]
The cathode extensions welded to each other that are not cut in the cathode cutting step may form a cathode busbar.
[27]
A first insulating member installation step of installing an insulating member to insulate between the negative electrode busbar and the positive electrode of the electrode stack may be further included.
[28]
The anode cutting step of cutting portions of the anode extensions that are not welded to each other may be further included.
[29]
The anode extensions welded to each other not cut in the anode cutting step may form an anode busbar.
[30]
A second insulating member installation step of installing an insulating member to insulate between the positive busbar and the negative electrode of the electrode stack may be further included.
[31]
In the secondary battery according to an embodiment of the present invention, in a secondary battery comprising a single electrode assembly in which a plurality of negative electrodes and positive electrodes are repeatedly stacked to cross each other, and a separator is laminated between the plurality of negative electrodes and positive electrodes, the electrode assembly A cathode tab portion formed at one end extending from the plurality of cathodes, an anode busbar spaced apart from the cathode tab portion at one end of the electrode assembly and electrically connecting the plurality of anodes to each other, and located on the opposite side of the end of the electrode assembly And a cathode busbar at the other end extending from the plurality of anodes and spaced apart from the anode tab at the other end of the electrode assembly, and electrically connecting the plurality of cathodes to each other.
Effects of the Invention
[32]
According to the present invention, there is an effect of minimizing variations in current density by securing an electron movement path inside the electrode assembly.
[33]
According to the present invention, there is an effect of improving output by securing an electron movement path inside the electrode assembly.
Brief description of the drawing
[34]
1 is a perspective view showing an electrode assembly according to an embodiment of the present invention.
[35]
2 is a side cross-sectional view showing a main part by cutting the electrode assembly along line AA of FIG. 1.
[36]
3 is a flowchart sequentially showing a method of manufacturing an electrode assembly according to an embodiment of the present invention.
[37]
4 is a side view schematically showing a lamination step in a method of manufacturing an electrode assembly according to an embodiment of the present invention.
[38]
5 is a side view schematically illustrating a welding step of a cathode and an anode in a method of manufacturing an electrode assembly according to an embodiment of the present invention.
[39]
6 is a side view schematically showing a cutting step in a method of manufacturing an electrode assembly according to another embodiment of the present invention.
[40]
7 is a perspective view showing a secondary battery according to an embodiment of the present invention.
Mode for carrying out the invention
[41]
Hereinafter, an electrode assembly according to a preferred embodiment of the present invention and a method of manufacturing the electrode assembly will be described in detail with reference to the accompanying drawings.
[42]
The terms or words used in the present specification and claims should not be construed as being limited to their usual or dictionary meanings, and the inventor may appropriately define the concept of terms in order to describe his own invention in the best way. It should be interpreted as a meaning and concept consistent with the technical idea of ​​the present invention based on the principle that there is. Accordingly, the embodiments described in the present specification and the configurations shown in the drawings are only the most preferred embodiment of the present invention and do not represent all the technical ideas of the present invention, and thus various It should be understood that there may be equivalents.
[43]
In the drawings, the size of each component or a specific part constituting the component is exaggerated, omitted, or schematically illustrated for convenience and clarity of description. Therefore, the size of each component does not entirely reflect the actual size. If it is determined that a detailed description of related known functions or configurations may unnecessarily obscure the subject matter of the present invention, such description will be omitted.
[44]
[45]
1 is a perspective view showing an electrode assembly according to an embodiment of the present invention, and FIG. 2 is a side cross-sectional view showing a main part by cutting the electrode assembly along line AA of FIG. 1.
[46]
1 and 2, in the electrode assembly according to an embodiment of the present invention, a plurality of cathodes 11 and anodes 13 are repeatedly stacked to cross each other, and a plurality of cathodes 11 and anodes 13 In the single electrode assembly 10 in which the separator 15 is stacked therebetween, a cathode tab portion 20 formed to extend from the plurality of cathodes 11 at one end of the electrode assembly 10, and the electrode assembly 10 A positive busbar 40 spaced apart from the negative electrode tab 20 at one end of the electrode and electrically connecting the plurality of positive electrodes 13 to each other, and a plurality of electrodes at the other end located on the opposite side of the one end of the electrode assembly 10 An anode tab portion 30 formed extending from the anode 13 and a cathode bus bar spaced apart from the anode tab portion 30 at the other end of the electrode assembly 10 and electrically connecting the plurality of cathodes 11 to each other Includes 50.
[47]
The positive electrode 13 may be an aluminum electrode current collector, and may include a positive electrode holding portion coated with a positive electrode active material and a positive electrode uncoated portion not coated with the positive electrode active material.
[48]
The positive electrode active material may be a lithium-containing transition metal oxide or a lithium chalcogenide compound such as LiCoO 2 , LiNiO 2 , LiMnO 2 , and LiMnO 4 .
[49]
The positive electrode holding unit may be formed by coating a positive electrode active material on at least one surface of the aluminum electrode current collector, and the remainder of the aluminum electrode current collector to which the positive electrode active material is not applied may be the positive electrode uncoated part.
[50]
The anode tab portion 30 may be electrically connected to the anode uncoated portion to extend from the anode 13.
[51]
The negative electrode 11 may be a copper electrode current collector, and may include a negative electrode holding part coated with a negative electrode active material and a negative electrode uncoated part not coated with the negative active material.
[52]
The negative electrode active material may be a crystalline carbon, amorphous carbon, a carbon composite material, a carbon material such as carbon fiber, a lithium metal or a lithium alloy.
[53]
The negative electrode holding unit may be formed by coating a negative electrode active material on at least one surface of the copper electrode current collector, and the remaining part of the copper electrode current collector to which the negative electrode active material is not applied may be the negative electrode uncoated part.
[54]
The negative electrode tab portion 20 may be electrically connected to the negative electrode uncoated portion to extend from the negative electrode.
[55]
The separator is, for example, any one substrate selected from the group consisting of polyethylene (PE), polystyrene (PS), polypropylene (PP), and a copolymer of polyethylene (PE) and polypropylene (PP). It can be prepared by coating a polyvinylidene fluoride-hexafluoropropylene copolymer (PVDF-HFP co-polymer).
[56]
The positive electrode bus bar 40 is formed of an electrode current collector extending from the positive electrode 13 of the electrode assembly 10 so as to be spaced apart from the negative electrode tab 20 at the end of the electrode assembly 10 where the negative electrode tab 20 is formed. I can. The positive busbar 40 may be spaced apart from the negative electrode tab part 20 to prevent a short circuit with the negative electrode tab part 20, and electrically connect the plurality of positive electrodes 13 to allow current to flow.
[57]
The anode busbar 40 may be made of aluminum.
[58]
The negative busbar 50 may be formed of an electrode current collector extending from the negative electrode 11 of the electrode assembly 10 so as to be spaced apart from the positive electrode tab part 30 at the end of the electrode assembly 10 where the positive electrode tab part 30 is formed. have. The cathode bus bar 50 may be spaced apart from the anode tab portion 30 to prevent a short circuit with the anode tab portion 30, and electrically connect the plurality of cathodes 11 to allow current to flow.
[59]
The cathode busbar 40 may be made of copper.
[60]
In a secondary battery of medium to large size or larger, temperature accumulates inside the battery due to an increase in thickness, and the accumulated temperature may cause the temperature of the secondary battery to rise.
[61]
The positive busbar 40 and the negative busbar 50 may be formed at positions diagonally symmetrical to each other with respect to the central portion C of the single electrode assembly 10. That is, the positive busbar 40 and the negative busbar 50 can maximize the separation distance between each other to dissipate heat dissipation due to the movement of current to the entire electrode assembly 10 to prevent the temperature increase of the secondary battery. And it may have an effect of increasing stability.
[62]
The anode busbar 40 and the cathode busbar 50 are each formed in plural to secure an electron transfer path evenly throughout the single electrode assembly, thereby preventing variations in current density and improving stability and output through heat distribution. You can get the effect.
[63]
Referring to FIG. 2, an insulating member 60 such as rubber or plastic may be installed between the anode bus bar 40 and the cathode 11 of the electrode assembly 10 according to another embodiment of the present invention.
[64]
The insulating member 60 is installed between the positive bus bar 40 and the negative electrode 11 to insulate between the positive bus bar 40 and the negative electrode 11 of the electrode assembly 10, and the positive bus bar 40 ) And the cathode 11 can be prevented from shorting.
[65]
In addition, the insulating member 60 is installed between the negative busbar 50 and the positive electrode 13 so as to insulate the negative busbar 50 and the positive electrode 13 of the electrode assembly 10 to insulate the negative busbar 50 A short circuit between) and the anode can be prevented.
[66]
Hereinafter, a method of manufacturing an electrode assembly according to an embodiment of the present invention will be described in detail with reference to the drawings.
[67]
3 is a flowchart sequentially showing a method of manufacturing an electrode assembly according to an embodiment of the present invention.
[68]
As shown in FIG. 3, a method of manufacturing an electrode assembly according to an embodiment of the present invention may include a lamination step (S1), a cathode welding step (S2), and a anode welding step (S3).
[69]
4 is a side view schematically showing a lamination step in a method of manufacturing an electrode assembly according to an embodiment of the present invention.
[70]
As shown in FIG. 4, in the stacking step S1, a single electrode stack may be formed by alternately stacking electrodes and separators. At this time, the cathode 11 may include the anode 13 and the cathode extension portion 50a, which is a portion having a length longer than that of the separator 15 at one end. In addition, the anode 13 may include an anode extension portion 40a at the other end thereof that is longer than the cathode 11 and the separator 15.
[71]
And in the lamination step (S1), the anode 13, the separator 15 having the anode tab 30 formed at one end, and the cathode 11 including the cathode extension 50a at one end are sequentially stacked. I can.
[72]
In addition, in the lamination step (S1), a cathode 11 having a cathode tab portion 20 formed at the other end, a separator 15, and an anode 13 including an anode extension portion 40a at the other end are sequentially stacked. I can make it.
[73]
As a result, in the lamination step,
[74]
An anode tab part 30 is formed at one end and an anode 13 including an anode extension 40a at the other end / a separator 15 includes a cathode extension 50a at one end and a cathode at the other end It may mean sequentially stacking the cathodes 11 on which the tabs 20 are formed.
[75]
[76]
5 is a side view schematically illustrating a welding step of a cathode and an anode in a method of manufacturing an electrode assembly according to an embodiment of the present invention.
[77]
As shown in FIG. 5, in the cathode welding step S2, a plurality of cathode extensions 50a included in the plurality of cathodes 11 may be welded to each other. Meanwhile, when the cathode extension portions 50a are welded to each other, portions of the cathode extension portions 50a that are spaced apart from the anode tab portion 30 may be welded.
[78]
In the anode welding step S3, a plurality of anode extensions 40a included in the plurality of anodes 13 may be welded to each other. Meanwhile, when the positive electrode extension portions 40a are welded to each other, portions of the positive electrode extension portions 40a that are spaced apart from the negative electrode tab portion 20 may be welded.
[79]
In this way, after welding the portion spaced apart from the anode tab portion 30 in the cathode extension portions 50a and welding the portion spaced apart from the cathode tab portion 20 in the anode extension portions 40a, the unwelded portion will be described later. Cutting in the cathode cutting step and the anode cutting step can prevent the risk of short circuit. That is, since the welded portions of the cathode extension portions 50a and the anode extension portions 40a remaining after cutting in the cathode cutting step and the anode cutting step are separated from the anode tab portion 30 and the cathode tab portion 20 and do not contact each other. The risk of short circuit can be eliminated.
[80]
In the cathode welding step (S2) and the anode welding step (S3), welding of the cathode extension part 50a and the anode extension part 40a may be welded by ultrasonic welding or thermal welding, respectively.
[81]
6 is a side view schematically showing a cutting step in a method of manufacturing an electrode assembly according to another embodiment of the present invention.
[82]
As shown in FIG. 6, the method of manufacturing an electrode assembly according to another embodiment of the present invention may further include a step of cutting the cathode of cutting portions of the cathode extensions 50a that are not welded to each other. In addition, an anode cutting step of cutting portions of the anode extension portions 40a that are not welded to each other may be further included. As the non-welded cathode extensions 50a and anode extensions 40a are cut, a short circuit between the cathode extensions 50a and the anode tabs 30 and the anode extensions 40a and the cathode tabs 20 ) And the possibility of a short circuit can be eliminated.
[83]
As a non-welded part, the cut-out part may be the ends of the electrode extensions 40a and 50a based on the direction parallel to the electrode tabs 20 and 30, or the electrode based on the direction toward the electrode tabs 20 and 30. They may be ends of the extensions 40a and 50a.
[84]
The anode extensions 40a welded to each other not cut in the anode cutting step may form the anode busbar 40. In addition, the cathode extension portions 50a welded to each other that are not cut in the cathode cutting step may form the cathode busbar 50.
[85]
Meanwhile, referring to FIG. 6, a first insulating member installation step of preventing short circuit by installing an insulating member 60 between the negative busbar 50 and the positive electrode 13 of the electrode stack may be further included. .
[86]
In addition, a second insulating member installation step of preventing a short circuit by installing an insulating member 60 between the positive busbar 40 and the negative electrode 11 of the electrode stack may be further included.
[87]
7 is a perspective view showing a secondary battery according to an embodiment of the present invention.
[88]
1, 2, and 7, in the secondary battery according to an embodiment of the present invention, a plurality of negative electrodes 11 and positive electrodes 13 are repeatedly stacked to each other, and a plurality of negative electrodes 11 and positive electrodes (13) In a secondary battery comprising a single electrode assembly (10) in which a separator (15) is stacked, a negative electrode tab portion (20) extending from the plurality of negative electrodes (11) at one end of the electrode assembly (10) ), a positive electrode bus bar 40 spaced apart from the negative electrode tab 20 at one end of the electrode assembly 10 and electrically connecting the plurality of positive electrodes 13 to each other, and the one end of the electrode assembly 10 The anode tab portion 30 formed by extending from the plurality of anodes 13 at the other end located on the opposite side of the electrode assembly 10 and the anode tab portion 30 at the other end of the electrode assembly 10 are spaced apart from the anode tab portion 30, It includes a cathode bus bar 50 electrically connected to each other.
[89]
The electrode assembly 10 may be accommodated in a case 3 such as a can member or a pouch together with an electrolyte.
[90]
[91]
As described above, according to the present invention, there is an effect of minimizing variation in current density by securing an electron movement path inside the electrode assembly.
[92]
According to the present invention, there is an effect of improving output by securing an electron movement path inside the electrode assembly.
[93]
[94]
As described above, the electrode assembly according to the present invention and a method of manufacturing the electrode assembly have been described with reference to the illustrated drawings, but the present invention is not limited by the embodiments and drawings described above, and the present invention is within the scope of the claims Various implementations are possible by those of ordinary skill in the art to which this belongs.
Claims
[Claim 1]
In the single electrode assembly (10) in which a plurality of cathodes 11 and anodes 13 are repeatedly stacked to be crossed and a separator 15 is stacked between the plurality of cathodes 11 and anodes 13, the electrode A negative electrode tab portion 20 extending from the plurality of negative electrodes 11 at one end of the assembly 10; A positive electrode bus bar 40 spaced apart from the negative electrode tab 20 at one end of the electrode assembly 10 and electrically connecting the plurality of positive electrodes 13 to each other; An anode tab portion 30 formed by extending from the plurality of anodes 13 at the other end of the electrode assembly 10 located on the opposite side of the one end; And a cathode bus bar 50 at the other end of the electrode assembly 10 and spaced apart from the anode tab 30 and electrically connecting the plurality of cathodes 11 to each other. Electrode assembly comprising a.
[Claim 2]
The electrode assembly according to claim 1, wherein the anode bus bar (40) and the cathode bus bar (50) are formed at positions symmetrical to each other around a central portion (C) of the electrode assembly (10).
[Claim 3]
The electrode assembly according to claim 1, wherein the anode busbar (40) and the cathode busbar (50) are formed in plural, respectively.
[Claim 4]
The method according to claim 1, wherein the positive busbar 40 is formed of an electrode current collector extending from the positive electrode 13, and the negative busbar 50 is formed of an electrode current collector extending from the negative electrode 11. Electrode assembly, characterized in that.
[Claim 5]
The method according to claim 1 or 4, installed between the anode bus bar 40 and the cathode 11 to insulate between the anode bus bar 40 and the cathode 11 of the electrode assembly 10, or Or an insulating member 60 installed between the cathode bus bar 50 and the anode 13 to insulate between the cathode bus bar 50 and the anode 13 of the electrode assembly 10 Electrode assembly, characterized in that.
[Claim 6]
Electrodes and separators are alternately stacked to form an electrode stack, but at one end, a cathode 11 including a cathode extension portion 50a that is longer than the anode 13 and the separator 15, and the other end A lamination step (S1) of forming an electrode stack using the anode 13 including the cathode 11 and the anode extension 40a, which is a portion having a length longer than that of the cathode 11 and the separator 15; A cathode welding step (S2) of welding the plurality of cathode extensions 50a included in the plurality of cathodes 11 to each other; And an anode welding step (S3) of welding the plurality of anode extensions 40a included in the plurality of anodes 13 to each other. Electrode assembly manufacturing method comprising a.
[Claim 7]
The method according to claim 6, wherein the lamination step (S1) comprises an anode 13 having an anode tab 30 formed at one end, a separator 15, and a cathode extension 50a at one end. ) Sequentially stacking the electrode assembly manufacturing method, characterized in that.
[Claim 8]
The method of claim 7, wherein when welding the cathode extensions 50a to each other in the cathode welding step (S2), the cathode extensions 50a are welded to a portion spaced apart from the anode tab 30 The electrode assembly manufacturing method.
[Claim 9]
The method according to claim 6, wherein the lamination step (S1) comprises a cathode 11 having a cathode tab 20 formed at the other end, a separator 15, and an anode 13 including an anode extension 50a at the other end. ), the electrode assembly manufacturing method, characterized in that sequentially stacked.
[Claim 10]
The method according to claim 9, wherein when welding the positive electrode extension portions 40a to each other in the positive electrode welding step (S3), a portion spaced apart from the negative electrode tab portion 20 in the positive electrode extension portions 40a is welded. The electrode assembly manufacturing method.
[Claim 11]
The method according to claim 6, wherein in the cathode welding step (S2) and the anode welding step (S3), welding of the cathode extension part 50a and the anode extension part 40a is performed by ultrasonic welding or thermal welding, respectively. Electrode assembly manufacturing method characterized in that.
[Claim 12]
The method of claim 6, further comprising a cathode cutting step of cutting portions of the cathode extensions 50a that are not welded to each other.
[Claim 13]
The method of claim 12, wherein the cathode extensions (50a) welded to each other that are not cut in the cathode cutting step form a cathode bus bar (50).
[Claim 14]
The electrode according to claim 13, further comprising a first insulating member installation step of installing an insulating member 60 to insulate between the negative electrode busbar 50 and the positive electrode 13 of the electrode stack. Assembly manufacturing method.
[Claim 15]
The method according to claim 6, further comprising: cutting the anode extension portions (40a) that are not welded to each other.
[Claim 16]
The method of claim 15, wherein the anode extensions (40a) welded to each other that are not cut in the anode cutting step form an anode busbar (40).
[Claim 17]
The electrode according to claim 16, further comprising a second insulating member installation step of installing an insulating member 60 to insulate between the positive busbar 40 and the negative electrode 11 of the electrode stack. Assembly manufacturing method.
[Claim 18]
A secondary battery including a single electrode assembly 10 in which a plurality of cathodes 11 and anodes 13 are repeatedly stacked to be crossed, and a separator 15 is stacked between the plurality of cathodes 11 and anodes 13 The method of (1), further comprising: a cathode tab portion 20 formed at one end of the electrode assembly 10 extending from the plurality of cathodes 11; A positive electrode bus bar 40 spaced apart from the negative electrode tab 20 at one end of the electrode assembly 10 and electrically connecting the plurality of positive electrodes 13 to each other; An anode tab portion 30 formed by extending from the plurality of anodes 13 at the other end of the electrode assembly 10 located on the opposite side of the one end; And a cathode bus bar 50 at the other end of the electrode assembly 10 and spaced apart from the anode tab 30 and electrically connecting the plurality of cathodes 11 to each other. A secondary battery comprising a.