The present invention relates to a secondary battery.
background
[5]
Secondary batteries, unlike primary batteries, are rechargeable, and have been widely researched and developed in recent years due to their small size and large capacity. As technology development and demand for mobile devices increase, the demand for secondary batteries as an energy source is rapidly increasing.
[6]
Secondary batteries are classified into coin cells, cylindrical cells, prismatic cells, and pouch cells according to the shape of the battery case. In a secondary battery, an electrode assembly mounted inside a battery case is a charging/discharging power generating element having a stacked structure of an electrode and a separator.
[7]
The electrode assembly is a jelly-roll type in which a separator is interposed between a positive electrode and a negative electrode of a sheet-type sheet coated with an active material, and a stack type in which a plurality of positive and negative electrodes are sequentially stacked with a separator interposed therebetween. , and stacked unit cells can be roughly classified into a stack/folding type in which a long-length separation film is wound. The double jelly roll type electrode assembly is widely used because it is easy to manufacture and has the advantage of high energy density per weight.
DETAILED DESCRIPTION OF THE INVENTION
technical challenge
[8]
One aspect of the present invention is to provide a secondary battery in which resistance is minimized and heat dissipation characteristics are improved.
[9]
In addition, another aspect of the present invention is to provide a secondary battery that is not limited by the meandering of the wound electrode when welding the can and the electrode.
[10]
In addition, another aspect of the present invention is to provide a secondary battery capable of improving electrode resistance and thermal deviation.
means of solving the problem
[11]
A secondary battery according to an embodiment of the present invention includes an electrode assembly in which a first electrode, a separator, and a second electrode are alternately stacked, and a can accommodating the electrode assembly, wherein the first electrode is not coated with the electrode active material. The first electrode uncoated portion is located at an end in one direction so as to protrude more than the separator with respect to the winding central axis direction of the electrode assembly, and the second electrode includes a second electrode uncoated portion on which the electrode active material is not coated, The electrode assembly is positioned at the other end of the electrode assembly to protrude further than the separator, and the can includes a first can and a second can, and the first electrode uncoated part is a portion of the first can. The first connection part is in contact with one end, the second electrode uncoated part is in contact with the second connection part located at the other end of the second can, and at least one of the first connection part and the second connection part is in an electrode assembly direction. It may include a protruding connection part of a protruding form.
Effects of the Invention
[12]
According to the present invention, since the electrode of the wound electrode assembly can be directly connected to the can and without a connecting member, resistance can be minimized and heat dissipation characteristics can be improved.
[13]
In addition, according to the present invention, a protruding connection portion protruding in the direction of the electrode assembly is formed on the can, so that when welding between the can and the electrode uncoated portion of the wound electrode assembly, the meandering of the wound electrode may not be affected.
[14]
In addition, according to the present invention, the welding position and the welding pattern between the can and the electrode uncoated region are uniformly formed, thereby improving electrode resistance and thermal deviation.
Brief description of the drawing
[15]
1 is a perspective view showing a secondary battery according to an embodiment of the present invention.
[16]
2 is a cross-sectional view illustrating a secondary battery according to an embodiment of the present invention.
[17]
3 is an exploded perspective view illustrating a secondary battery according to an embodiment of the present invention.
[18]
4 is a perspective view illustrating a concept of an electrode assembly in a secondary battery according to an embodiment of the present invention.
[19]
5 is a perspective view showing a portion of a first can cut away in a secondary battery according to an embodiment of the present invention.
[20]
6 is an enlarged perspective view of a part of a secondary battery cut out according to an embodiment of the present invention.
[21]
7 is a perspective view illustrating a secondary battery according to another embodiment of the present invention.
[22]
8 is a cross-sectional view illustrating a secondary battery according to another embodiment of the present invention.
[23]
9 is a front view illustrating an unfolded state before winding a first electrode in a secondary battery according to another embodiment of the present invention.
[24]
10 is an enlarged and enlarged perspective view of a part of a secondary battery according to another embodiment of the present invention.
[25]
11 is a plan view illustrating a secondary battery according to another embodiment of the present invention.
[26]
12 is a plan view illustrating a part of a first case in a secondary battery according to another embodiment of the present invention.
[27]
13 is a view exemplarily illustrating the concept of a welding pattern in a secondary battery according to another embodiment of the present invention.
Modes for carrying out the invention
[28]
The objects, specific advantages and novel features of the present invention will become more apparent from the following detailed description taken in conjunction with the accompanying drawings and preferred embodiments. In the present specification, in adding reference numbers to the components of each drawing, it should be noted that only the same components are given the same number as possible even though they are indicated on different drawings. In addition, the present invention may be embodied in several different forms and is not limited to the embodiments described herein. And, in describing the present invention, detailed descriptions of related known technologies that may unnecessarily obscure the gist of the present invention will be omitted.
[29]
[30]
1 is a perspective view illustrating a secondary battery according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view illustrating a secondary battery according to an embodiment of the present invention.
[31]
1 and 2 , a secondary battery 100 according to an embodiment of the present invention includes an electrode assembly 110 , a first can 121 and a second can accommodating the electrode assembly 110 therein. A can 120 including 122 , and an insulator 123 insulating an overlapping portion between the first can 121 and the second can 122 .
[32]
[33]
3 is an exploded perspective view illustrating a secondary battery according to an embodiment of the present invention, and FIG. 4 is a perspective view illustrating a concept of an electrode assembly in the secondary battery according to an embodiment of the present invention.
[34]
Hereinafter, a secondary battery according to an embodiment of the present invention will be described in more detail with reference to FIGS. 1 to 7 .
[35]
2 to 4 , the electrode assembly 110 is a power generating element capable of charging and discharging, and the electrode 113 and the separator 114 are assembled to form a structure in which they are alternately stacked. Here, the electrode assembly 110 may have a wound shape.
[36]
The electrode 113 may include a first electrode 111 and a second electrode 112 . The separator 114 separates and electrically insulates the first electrode 111 and the second electrode 112 . Here, the first electrode 111 and the second electrode 112 may be formed in a sheet shape, wound together with the separator 114 , and formed in a jelly roll shape. In this case, the electrode assembly 110 may be wound in a cylindrical shape, for example.
[37]
On the other hand, the first electrode 111 is made of an anode, and the second electrode 112 can be made of a cathode, but the present invention is not necessarily limited thereto, and the first electrode 111 is made of a cathode, Of course, the second electrode 112 may be formed of an anode.
[38]
The first electrode 111 may include a first electrode current collector 111a and a first electrode active material 111b applied to the first electrode current collector 111a. In addition, the first electrode 111 may include the first electrode uncoated region 111c on which the first electrode active material 111b is not coated. Here, the first electrode uncoated region 111c may be positioned at an end of the electrode assembly 110 in the one direction S1 so as to protrude more than the separator 114 with respect to the winding central axis S of the electrode assembly 110 .
[39]
In addition, the first electrode 111 is made of, for example, a negative electrode, and includes a negative electrode current collector (not shown) and a negative electrode active material (not shown) coated on the negative electrode current collector, and a negative electrode uncoated region on which the negative electrode active material is not coated is formed. can be
[40]
The negative electrode current collector may be made of, for example, a foil made of a copper (Cu) or nickel (Ni) material. The anode active material may be made of, for example, artificial graphite, lithium metal, lithium alloy, carbon, petroleum coke, activated carbon, graphite, a silicon compound, a tin compound, a titanium compound, or an alloy thereof. In this case, the negative active material may further include, for example, non-graphite-based SiO (silica, silica) or SiC (silicon carbide, silicon carbide).
[41]
The second electrode 112 may include a second electrode current collector 112a and a second electrode active material 112b applied to the second electrode current collector 112a. In addition, the second electrode 112 may include the second electrode uncoated region 112c on which the second electrode active material 112b is not coated. Here, the second electrode uncoated region 112c may be positioned at the end of the second electrode assembly 110 in the other direction S2 to protrude more than the separator 114 with respect to the winding central axis S of the electrode assembly 110 .
[42]
Here, the second electrode 112 is made of, for example, a positive electrode, and includes a positive electrode current collector (not shown) and a positive electrode active material (not shown) applied to the positive electrode current collector, and a positive electrode uncoated region on which the positive electrode active material is not coated is formed. can be
[43]
The positive electrode current collector may be made of, for example, aluminum foil, and the positive electrode active material may include, for example, lithium manganese oxide, lithium cobalt oxide, lithium nickel oxide, lithium iron phosphate, or at least one of these. It may consist of compounds and mixtures, and the like.
[44]
The separator 114 is made of an insulating material and is alternately stacked with the first electrode 111 and the second electrode 112 . Here, the separator 114 may be positioned between the first electrode 111 and the second electrode 112 and on the outer surface of the first electrode 111 and the second electrode 112 . In this case, the separator 114 may be positioned at the outermost side in the width direction when the electrode assembly 110 is wound.
[45]
In addition, the separator 114 may be made of a flexible material. In this case, the separator 114 may be formed of, for example, a polyolefin-based resin film such as polyethylene or polypropylene having microporosity.
[46]
[47]
The can 120 may include a first can 121 and a second can 122 in which an accommodating part for accommodating the electrode assembly 110 is formed therein, and formed in a cylindrical shape opened in a direction opposite to each other.
[48]
In addition, the can 120 may be formed of a conductive material. Here, the can 120 may include metal. Here, as an example, the first can 121 may be made of aluminum and the second can 122 may be made of steel. Meanwhile, as another example, the first can 121 may be made of steel and the second can 122 may be made of aluminum. In this case, for example, a can made of aluminum may be connected to the anode, and a can made of steel may be connected to the cathode.
[49]
Also, the first can 121 may be electrically connected to the first electrode 111 , and the second can 122 may be electrically connected to the second electrode 112 . In this case, the first can 121 is in direct contact with the end of the first electrode 111 to form a first electrode terminal, and the second can 122 is in direct contact with the end of the second electrode 112 to form a second electrode terminal. An electrode terminal can be formed.
[50]
To describe one case, when the first electrode 111 is a positive electrode, the first can 121 in contact with the end of the first electrode 111 forms a positive terminal, and in this case, the first can 121 is It may be made of aluminum. And in this case, the second electrode 112 becomes the negative electrode, and the second can 122 to which the end of the second electrode 112 is in contact forms a negative terminal, and in this case, the second can 122 is made of steel. can
[51]
In addition, the first can 121 and the second can 122 may be formed to correspond to each other.
[52]
In addition, the first can 121 and the second can 122 are formed in a cylindrical shape opened in a direction facing each other, and the inner circumferential surface of the first can 121 is larger than the outer circumferential surface of the second can 122, The second can 122 may be inserted into the first can 121 .
[53]
The first can 121 has a first opening 121d that is opened in the other direction S2 at the other end thereof, and the second can 122 has a second opening 121d that is opened in one direction S1 at one end of the first can 121 . not shown) may be formed. At this time, the second connection part 122a positioned in the other direction S2 of the second can 122 is located outside the first can 121 even after the second can 122 is inserted into the first can 121 . can be located.
[54]
In addition, one end of the first electrode 111 may be connected to the first connection part 121a , and the other end of the second electrode 112 may be connected to the second connection part 122a . Here, for example, the first electrode uncoated region 111c of the first electrode 111 is in direct contact with the first connection portion 121a, and the second electrode uncoated region 112c of the second electrode 112 is connected to the second It may be in direct contact with the connection part 122a.
[55]
[56]
5 is a perspective view showing a part of a first can cut out from a secondary battery according to an embodiment of the present invention, and FIG. 6 is an enlarged perspective view showing a part of a secondary battery according to an embodiment of the present invention, which is cut out.
[57]
Referring to FIGS. 2, 5 and 6 , the protruding connection part may be formed to protrude in the electrode assembly 110 direction, for example, on at least one of the first connection part 121a and the second connection part 122a. there is.
[58]
In more detail, a first protruding connection part 121b protruding toward the electrode assembly 110 is formed on the first connection part 121a of the first can 121 , and the first electrode uncoated part is formed on the first protrusion connection part 121b. 111c can be connected. In addition, a second protruding connecting portion (not shown) protruding toward the electrode assembly 110 may be formed on the second connecting portion 122a, and the second electrode uncoated portion 112c may be connected to the second protruding connecting portion. Here, the second protrusion connection part may be formed in a shape corresponding to the first protrusion connection part 121b.
[59]
In addition, the first protruding connecting portion 121b and the second protruding connecting portion are bent in the direction of the electrode assembly 110 to form a concave portion on the outer surface of the first can 121 , and the first can A convex portion may be formed on the inner surface of (121).
[60]
In addition, the first electrode uncoated region 111c may be welded to the first protruding connection portion 121b and fixed, and the second electrode uncoated region 112c may be welded to and fixed to the second protruding connection portion.
[61]
In addition, the first protruding connection part 121b is formed in the shape of a plurality of circles having different diameters in a plan view on the first connection part 121a, and the first protrusion part 121b-1 is formed from the outer shell of the first connection part 121a toward the center. ), the second protrusion 121b-2 and the third protrusion 121b-3 may be sequentially formed.
[62]
On the other hand, also in the second connection part 122a of the second can 122 , a second protrusion connection part (not shown) corresponding to the first protrusion connection part 121b formed in the first connection part 121a of the first can 121 . ) can be formed. In this case, the second electrode uncoated portion 112c of the second electrode 112 may be welded to the second protruding connection portion formed in the second connection portion 122a.
[63]
[64]
Referring to FIG. 2 , the insulator 123 may include an insulating material to insulate an overlapping portion between the first can 121 and the second can 122 .
[65]
In addition, the insulator 123 may include an insulating polymer. In this case, the insulating polymer may be, for example, a polymer.
[66]
[67]
2 and 6 , in the secondary battery 100 according to an embodiment of the present invention configured as described above, the first electrode 111 and the second electrode 112 of the wound electrode assembly 110 are Since it can be directly connected to the first can 121 and the second can 122 without a connecting member, resistance can be minimized and heat dissipation characteristics can be improved. In addition, a protruding connection part protruding in the electrode assembly 110 direction is formed on the can 120 , so that the first electrode uncoated region 111c and the second electrode uncoated region 112c and the first uncoated region 111c of the wound electrode assembly 110 are formed. When welding between the can 121 and the second can 122 , it may not be limited by the meandering of the wound first electrode 111 and the second electrode 112 (the meandering is not evenly rolled during winding, but obliquely rolled during winding). meaning). That is, when winding the electrode, meandering may normally occur to some extent. When the meandering occurs, a portion that cannot be contacted during welding occurs between the electrode uncoated region and the can. According to the present invention, by forming the protruding connection part on the can, the electrode uncoated part and the can can be in good contact with each other even when a meandering part occurs during winding of the electrode. Accordingly, sufficient welding is possible. 6 illustrates a state in which the uncoated region of the first electrode is in good contact with the inner surface of the can by bending where the protruding connection portion is present.
[68]
[69]
Hereinafter, a secondary battery according to another embodiment will be described.
[70]
7 is a perspective view illustrating a secondary battery according to another embodiment of the present invention, and FIG. 8 is a cross-sectional view illustrating a secondary battery according to another embodiment of the present invention.
[71]
7 and 8 , the secondary battery 200 according to another embodiment of the present invention includes an electrode assembly 210 , and a first can 221 and a second can accommodating the electrode assembly 210 therein. A can 220 including 222 , and an insulator 223 insulating an overlapping portion between the first can 221 and the second can 222 .
[72]
The secondary battery 200 according to another embodiment of the present invention further includes a configuration of a welding pattern for welding the can 220 and the electrode 213 when compared to the secondary battery according to the above-described embodiment. There is a difference. Accordingly, in this embodiment, content overlapping with the embodiment will be briefly described, and differences will be mainly described.
[73]
[74]
9 is a front view illustrating an unfolded state before winding a first electrode in a secondary battery according to another embodiment of the present invention.
[75]
More specifically, referring to FIGS. 8 and 9 , in the secondary battery 200 according to another embodiment of the present invention, the electrode assembly 210 has a structure in which electrodes 213 and separators 214 are assembled and stacked alternately. to form Here, the electrode assembly 210 may have a wound shape.
[76]
The electrode 213 may include a first electrode 211 and a second electrode 212 .
[77]
The first electrode 211 may include a first electrode current collector 211a and a first electrode active material 211b applied to the first electrode current collector 211a. In addition, the first electrode 211 may include the first electrode uncoated region 211c on which the first electrode active material 211b is not coated.
[78]
The second electrode 212 may include a second electrode current collector 212a and a second electrode active material 212b applied to the second electrode current collector 212a. In addition, the second electrode 212 may include the second electrode uncoated region 212c on which the second electrode active material 212b is not coated.
[79]
[80]
10 is an enlarged perspective view showing a part of a secondary battery according to another embodiment of the present invention, in which a cut-away part is shown, and FIG. 11 is a plan view showing a secondary battery according to another embodiment of the present invention. 12 is a plan view exemplarily showing a part of a first case in a secondary battery according to another embodiment of the present invention, and FIG. 13 is an exemplary view illustrating the concept of a welding pattern in a secondary battery according to another embodiment of the present invention. It is a drawing shown as
[81]
Referring to FIGS. 8 and 10 , the can 220 includes a first can 221 and a second can that are formed in a tubular shape having a receiving portion accommodating the electrode assembly 210 therein, and open in opposite directions. (222).
[82]
Here, the first can 221 may be electrically connected to the first electrode 211 , and the second can 222 may be electrically connected to the second electrode 212 .
[83]
A first protruding connecting portion 121b protruding toward the electrode assembly 210 is formed in the first connecting portion 221a of the first can 221 , and the first electrode uncoated portion 211c is formed in the first protruding connecting portion 221b. can be connected. In addition, a second protruding connecting portion (not shown) protruding toward the electrode assembly 210 may be formed on the second connecting portion 222a, and the second electrode uncoated portion 212c may be connected to the second protruding connecting portion.
[84]
The first protruding connecting portion 221b and the second protruding connecting portion are bent in the direction of the electrode assembly 210 to form a concave portion on the outer surface of the first can 221 and a convex portion on the inner surface of the can. can
[85]
The first electrode uncoated portion 211c may be welded to the first protruding connection portion 221b and fixed, and the second electrode uncoated portion 212c may be welded to and fixed to the second protruding connection portion.
[86]
9 to 11 , the first protruding connection part 221b is formed in the shape of a plurality of circles having different diameters in a plan view on the first connection part 221a, and at the outer shell O of the first connection part 221a A first protrusion 221b-1, a second protrusion 221b-2, and a third protrusion 221b-3 may be sequentially formed in the winding center S direction.
[87]
In addition, a gap between the first protrusion 221b - 1 and the second protrusion 221b - 2 may be formed to be smaller than a distance between the second protrusion 221b - 2 and the third protrusion 221b - 3 .
[88]
Here, in the first electrode uncoated region 211c, three portions of the first electrode connection portions 211d spaced apart from each other in the longitudinal direction L of the first electrode 211 include a first protrusion 221b-1, It may be connected to the second protrusion 221b - 2 and the third protrusion 221b - 3 . Specifically, the first electrode connection portion 211d includes three portions of the first welding portion 211d-1, the second welding portion 211d-2, and the third welding portion 211d-3 spaced apart from each other in the longitudinal direction L. The first welding part 211d-1, the second welding part 211d-2, and the third welding part 211d-3 may each include a first protrusion 221b-1 and a second protrusion 221b-, respectively. 2) and the third protrusion 221b-3.
[89]
In addition, when winding along the longitudinal direction L of the first electrode 211, the first welding portion 211d-1 and the second A second welding part 211d-2 and a third welding part 211d-3 are sequentially provided, respectively, to the first protrusion 221b-1, the second protrusion 221b-2, and the third protrusion 221b-3, respectively. It can be welded and fixed.
[90]
In addition, a movement path P of electric charge and heat of the first electrode 211 may be directed toward the first welding part 211d-1, the second welding part 211d-2, and the third welding part 211d-3. . Here, the length of the first electrode 211 in the longitudinal direction L may be, for example, 3780 mm. In this case, for example, the welding portion of the first welding portion 211d-1 and the first protrusion 221b-1 is located at a distance of 10.3 mm from the winding center S in a plan view of the wound electrode assembly 110 at a distance. and the welding portion of the second welding portion 211d-2 and the second protrusion 221b-2 is located at a distance of 16.7 mm from the winding center S in a plan view of the wound electrode assembly 110, The welding portions of the third welding portion 211d - 3 and the third protruding portion 221b - 3 may be located at a distance of 21.3 mm from the winding center S in a plan view of the wound electrode assembly 110 .
[91]
In addition, the first electrode 211 includes a first region S1 and a second region S2 in which the first electrode 211 is equally divided into thirds along the longitudinal direction L of the first electrode 211 . , and a third region S3 , wherein the first welding part 211d-1, the second welding part 211d-2, and the third welding part 211d-3 are the first region S1 and the second region ( S2) and the third region S3 may be located at each central portion. Here, for example, the first region S1 , the second region S2 , and the third region S3 may each have the same length of 1260 mm.
[92]
And, referring to FIG. 9 showing the unfolded state before the winding of the first electrode 211, the gap d1 between the first welding part 211d-1 and the second welding part 211d-2 is the second welding part ( The distance d2 between the 211d-2 and the third welding part 211d-3 may be the same. At this time, the welding length w1 of the first welding part 211d-1, the welding length w2 of the second welding part 211d-2, and the welding length w3 of the third welding part 211d-3 are equal to each other. can do. Here, for example, the welding length w1 of the first welding part 211d-1, the welding length w2 of the second welding part 211d-2, and the welding length w3 of the third welding part 211d-3 are used. may be equally formed to be 200 to 300 mm, respectively.
[93]
When uniformly formed in this way, a balanced and smooth transfer of charges or a balanced and smooth movement of heat may be possible.
[94]
9 to 13 , the welding pattern A of the first welding part 211d-1 and the first protrusion 221b-1 is formed in a straight shape, and the second welding part 211d-2 and the second welding part 211d-2 are formed in a straight line. The welding pattern (B) of the protrusion (221b-2) is formed in a zigzag (ZigZag) shape, and the welding pattern (C) of the third welding part (211d-3) and the third protrusion (221b-3) is the second welding part ( 211d-2) and the second protrusion 221b-2 may be formed in a zigzag shape having a width wider than that of the zigzag welding pattern B. For reference, when referring to partially enlarged FIGS. 12 and 13, welding patterns A, B, and C are shown in straight and zigzag shapes, but when referring to FIG. 11 showing the whole in a plan view, welding pattern A ,B,C can form a circle as a whole. That is, the welding pattern A may form a circle in a straight shape, and the welding pattern B and the welding pattern C may form a circle in a zigzag shape.
[95]
As a result, the first welding part 211d-1, the second welding part 211d-2, and the third welding part 211d-3 of the first electrode connection part 211d form the first protrusion part 221b of the first protruding connection part 221b. -1), the second protrusion 221b-2, and the third protrusion 221b-3 each have a uniform welding area and may be fixed. Accordingly, it is possible to prevent the occurrence of electrode resistance and thermal deviation by having a uniform contact area.
[96]
In more detail, the welding pattern A of the first welding part 211d-1 and the first protrusion 221b-1 shown in the plan view of the first connection part 221a is located at the outer shell O to form the largest circle. and the welding pattern (B) of the second welding part (211d-2) and the second protrusion part (221b-2) is on the welding pattern (A) of the first welding part (211d-1) and the first projection part (221b-1). A smaller circle is formed, and the welding pattern C of the third welding part 211d-3 and the third protrusion 221b-3 is located at the winding center S in a plan view to form the smallest circle. . Accordingly, the lengths of the respective welding patterns are different, and in order to prevent a problem that may cause non-uniform welding area and cause electrode resistance and thermal deviation, the width of each welding pattern is changed to correspond to the uniformity. It can be made to have a welding area.
[97]
For reference, in the first electrode 211 , the welding length w1 of the first welding part 211d-1, the welding length w2 of the second welding part 211d-2, and the third welding part 211d-3 are Although the welding lengths w3 are equal to each other, when the first electrode 211 is wound, the first welding part 211d-1 is located at the outermost side and, for example, if it is wound once, the second welding part 211d-2 is It may be wound twice, and the third welding part 211d-3 may be wound three times. At this time, if the second welding part 211d-2 and the third welding part 211d-3 are welded by the width of one ply of the first welding part 211d-1, the welding area becomes non-uniform. Therefore, when welding the second welding portion 211d-2, the width of the welding pattern B must be wider than the width of the welding pattern A when welding the first welding portion 211d-1. -1) and the area in which the second welding part 211d-2 is actually welded becomes the same. To this effect, the width of the welding pattern (C) for welding the third welding portion (211d-3) is formed wider than the welding pattern (B) for welding the second welding portion (211d-2) to have a uniform welding area. It may be possible to prevent the occurrence of electrode resistance and thermal variations.
[98]
For example, the welding pattern C of the third welding part 211d-3 and the third protruding part 221b-3 is a welding pattern B of the second welding part 211d-2 and the second protruding part 221b-2. It can be formed in a zigzag shape having a width twice or more than that.
[99]
Here, for example, the zigzag welding pattern B of the second welding portion 211d-2 and the second protruding portion 221b-2 has a zigzag bending angle α of 120° to 140°, and the third welding portion 211d -3) and the zigzag welding pattern C of the third protrusion 221b-3 may have a zigzag bending angle ß of 80° to 100°. When the numerical limiting condition of the above welding pattern is satisfied, the first welding part 211d-1, the second welding part 211d-2, and the third welding part 211d-3 are formed with the first protrusion ( 221b-1), the second protrusion 221b-2, and the third protrusion 221b-3 may each have a uniform welding area.
[100]
Meanwhile, in the second connection part 222a of the second can 222 , a second protrusion connection part (not shown) corresponding to the first protrusion connection part 221b formed in the first connection part 221a of the first can 221 . ) can be formed. In this case, the second electrode uncoated part 212c of the second electrode 212 is connected to the first protruding connection part 221b in the second protruding connection part formed in the second connection part 222a, and the first electrode uncoated part of the first electrode 211 is connected to the first protruding connection part 221b. The portion 211c may have the same welding pattern as that of the welded portion, and may be connected to each other by welding.
[101]
8, 10, and 12 , the secondary battery 200 according to another embodiment of the present invention configured as described above includes the first can 221 and the second can 222 and the first electrode uncoated region. By uniformly forming a welding position and a welding pattern between the 211c and the second electrode uncoated region 212c, electrode resistance and thermal deviation may be improved.
[102]
[103]
Although the present invention has been described in detail through specific examples, it is intended to describe the present invention in detail, and the secondary battery according to the present invention is not limited thereto. It will be said that various implementations are possible by those of ordinary skill in the art within the technical spirit of the present invention.
[104]
In addition, the specific protection scope of the invention will be made clear by the appended claims.

Claims
[Claim 1]
an electrode assembly in which a first electrode, a separator, and a second electrode are alternately stacked; and a can accommodating the electrode assembly, wherein the first electrode has a first electrode uncoated portion on which the electrode active material is not coated, in one direction such that the first electrode uncoated portion protrudes more than the separator with respect to a winding central axis direction of the electrode assembly. It is located at the end, and the second electrode is located at the other end so that the second electrode uncoated portion, on which the electrode active material is not coated, protrudes more than the separator with respect to the central axis of winding of the electrode assembly, and the can silver includes a first can and a second can, wherein the first electrode uncoated portion is in contact with a first connection portion positioned at one end of the first can, and the second electrode uncoated portion is positioned at the other end of the second can. A secondary battery in contact with a second connection part, wherein at least one of the first connection part and the second connection part includes a protruding connection part protruding toward an electrode assembly.
[Claim 2]
The method according to claim 1, wherein the first connecting portion is formed with a first protruding connecting portion protruding in the electrode assembly direction, the first electrode uncoated portion is connected to the first protruding connecting portion, and the second connecting portion in the electrode assembly direction A secondary battery in which a protruding second protruding connection part is formed, and the second electrode uncoated part is connected to the second protruding connection part.
[Claim 3]
The secondary according to claim 2, wherein the first protruding connecting portion and the second protruding connecting portion are formed to be bent in the direction of the electrode assembly to form a concave portion on an outer surface of the can and a convex portion on an inner surface of the can battery.
[Claim 4]
The secondary battery of claim 3 , wherein the first electrode uncoated portion is welded to the first protruding connecting portion and fixed to the first protruding connecting portion, and the second electrode uncoated portion is welded to and fixed to the second protruding connecting portion.
[Claim 5]
The method according to claim 4, wherein the first protruding connection portion is formed in the form of a plurality of circles having different diameters in a plan view of the first connection portion, a first projection, a second projection and a A secondary battery in which 3 protrusions are sequentially formed.
[Claim 6]
The method according to claim 5, wherein in the first electrode uncoated region, three first electrode connection portions spaced apart from each other by a predetermined interval in the longitudinal direction of the first electrode are respectively connected to the first protrusion, the second protrusion and the third protrusion. secondary battery.
[Claim 7]
The method according to claim 6, The first electrode connection portion, when winding along the longitudinal direction of the first electrode, a first welding portion, a second welding portion, and a third welding portion are provided sequentially from a portion located at the outer shell toward the center, The secondary battery is welded and fixed to each of the first protrusion, the second protrusion, and the third protrusion.
[Claim 8]
The method according to claim 7, wherein the welding pattern of the first welding portion and the first protrusion is formed in a straight line shape, the welding pattern of the second welding portion and the second protrusion is formed in a zigzag shape, and the third welding portion and the first protrusion are formed in a zigzag shape. 3 The welding pattern of the protrusion is formed in a zigzag shape having a width wider than that of the second welding part and the zigzag welding pattern of the second protrusion.
[Claim 9]
The rechargeable battery of claim 8 , wherein the welding pattern of the third welding part and the third protrusion is formed in a zigzag shape having a width that is at least twice that of the welding pattern of the second welding part and the second protrusion.
[Claim 10]
The method according to claim 8, The zigzag welding pattern of the second welding portion and the second protrusion has a zigzag bending angle of 120° to 140°, and the zigzag welding pattern of the third welding portion and the third protrusion has a zigzag bending angle of 80°. ~100° secondary battery.
[Claim 11]
The rechargeable battery of claim 7 , wherein a distance between the first protrusion and the second protrusion is smaller than a distance between the second protrusion and the third protrusion.
[Claim 12]
The method according to claim 7, wherein the first electrode includes a first region, a second region, and a third region that are regions in which the first electrode is equally divided into thirds along the longitudinal direction of the first electrode, the first welding portion; The second welding part and the third welding part are located in the center of each of the first region, the second region, and the third region.
[Claim 13]
The method according to claim 1, wherein the first can and the second can are formed in a cylindrical shape opened in a mutually facing direction, the outer peripheral surface of the first can is formed to be larger than the inner peripheral surface of the second can, the second can is A secondary battery inserted into the first can.
[Claim 14]
The secondary battery of claim 13 , wherein the first can has a first opening opened in the other direction at the other end thereof, and the second can has a second opening that is opened in one direction at one end of the second can.
[Claim 15]
The secondary battery of claim 14 , wherein the second connection part is positioned outside the first can even after the second can is inserted into the first can.