KR100601515B1 - Secondary battery - Google Patents

Abstract

The present invention relates to a secondary battery, the technical problem to be solved by removing the positive electrode tab, using a flexible wiring film instead of the negative electrode tab, by increasing the number of winding and height (area) of the electrode assembly to increase the battery capacity, By directly welding a predetermined region of the electrode assembly to the can, the electrode assembly and the can are directly connected to each other, and a positive temperature element is provided therein to improve the safety of the battery.

Summary of the Invention To achieve the object of the present invention, a can of a substantially hexahedral shape having an opening on one side, and a first electrode plate, a separator, and a second electrode plate are stacked and wound a plurality of times inside the can. The first electrode plate is directly connected to the inner surface of the can, and the electrode assembly is connected to the second electrode plate and is connected to a flexible wiring film having a positive temperature element extending a predetermined length to the outside, and a cap plate coupled to an opening of the can. The cap plate includes a cap assembly coupled with an electrode terminal to which the flexible wiring film is connected.

Secondary battery, can, electrode assembly, pole plate, flexible wiring film, positive temperature element

Description

Secondary battery

1 is a perspective view illustrating a rechargeable battery according to the present invention.

2 is an exploded perspective view illustrating a rechargeable battery according to the present invention.

FIG. 3 is an enlarged perspective view of region 1 of FIG. 2.

4 is a cross-sectional view taken along the line 2-2 of FIG.

5 is a cross-sectional view taken along line 3-3 of FIG.

FIG. 6 is an enlarged cross-sectional view of four areas of FIG. 5.

FIG. 7 is an enlarged cross-sectional view of five regions of FIG. 5.

8 is a cross-sectional view taken along line 6-6 of FIG.

9 is an enlarged cross-sectional view of area 7 of FIG. 8.

10 is a cross-sectional view taken along line 8-8 of FIG. 1.

<Description of Symbols for Main Parts of Drawings>

300; Secondary battery according to the present invention

310; Can 311; Long side

312; Short side 313; Bottom

314; Opening 315; Welding area

320; Electrode assembly 321; Long side

322; Short side 323; First electrode plate

324; Separator 325; 2nd electrode plate

326 '; Flexible wiring film 326a; Conductive wiring

326b; Insulating flexible film 326c; Positive temperature element

327a, 327b, 327c; 1, 2, 3 insulation tape

328; Conductive member 329; Welding area

330; Cap assembly 331; Insulated case

331a; Through 331b; Electrolyte inlet

332; Terminal plate 332a; Through

333; Insulation plate 333a; Through

334; Cap plate 334a; Through

334b; Electrolyte injection hole 334c; Safety vent

335; Insulating gasket 336 '; Electrode terminals

337; ball

The present invention relates to a secondary battery, and more particularly, to increase the battery capacity by directly connecting the electrode assembly to the can instead of removing the positive electrode tab, to prevent the flow and noise of the electrode assembly inside the can, and also positive A secondary battery improves safety by installing a temperature element inside a can.

Generally, secondary batteries (for example, lithium ion batteries) are classified into rectangular batteries, cylindrical batteries, and pouch batteries according to their form. Among them, the prismatic battery includes a can of a hexahedral shape having one side open, an electrode assembly inserted into the can and charged and discharged at a predetermined voltage, an electrolyte injected into the can to allow ion movement in the electrode assembly, an electrode assembly and an electrolyte solution. It consists of a cap assembly that closes the top of the can so that it does not spill out. Here, the cap assembly includes a cap plate coupled to an open area of the can and having a negative terminal coupled to the center through an insulating gasket.

In addition, the electrode assembly has a shape in which the cathode plate, the separator, and the cathode plate are stacked in the form of a jelly roll in a plurality of times. In addition, a positive electrode tab is connected to the positive electrode plate, and the positive electrode tab is welded to a cap plate of the cap assembly.

 In addition, a negative electrode tab is connected to the negative electrode plate, and the negative electrode tab is connected to a negative electrode terminal of the cap assembly. Accordingly, the cap plate and the can, except for the negative terminal formed on the cap assembly, have an overall positive property.

However, such a conventional secondary battery has a problem in that the positive electrode tab and the negative electrode tab having a relatively large thickness are connected to the electrode assembly, thereby limiting the number of turns of the electrode assembly. That is, since the positive electrode tab and the negative electrode tab itself have a predetermined thickness, the number of windings of the electrode assembly accommodated in the can is reduced, thereby reducing the capacity of the secondary battery. Of course, since the insulating tape is attached to the surfaces of the positive electrode tab and the negative electrode tab to prevent electrical shorts with the negative electrode plates or the positive electrode plates having different polarities, the number of windings of the electrode assembly is further reduced, and thus the battery capacity is further increased. Will be reduced.

Furthermore, the conventional secondary battery has a disadvantage in that the height of the electrode assembly must be made much smaller than the height of the can in order to easily connect the positive electrode tab and the negative electrode tab to the cap plate or the negative electrode terminal and prevent unnecessary short phenomenon. Of course, if the height of the electrode assembly is small, it is natural that the battery capacity is reduced by that much.

In addition, in the conventional secondary battery manufacturing process, not only the positive electrode tab and the negative electrode tab should be connected to the positive electrode plate and the negative electrode plate of the electrode assembly individually, but also each should be connected to the cap plate and the negative electrode terminal of the cap assembly again, The process is complicated, and thus there is a problem that the production yield is also lowered.

In addition, the electrode assembly accommodated in the can is assembled in such a way that the volume is approximately similar to the internal volume of the can, so that the electrode assembly flows inside the can even if the volume of the electrode assembly is only slightly smaller than the internal volume of the can. When the electrode assembly flows as described above, the positive electrode plate formed on the outermost surface of the electrode assembly intermittently contacts the can, and thus the output voltage or current of the secondary battery is not constant, and in severe cases, the positive electrode tab and the negative electrode tab are connected to the electrode assembly or cap. There is also the problem of separation from the assembly. Of course, the electrode assembly may also cause noise as it flows inside the can.

On the other hand, such a secondary battery also has a problem in that the manufacturing process is complicated by electrically connecting the positive temperature element to the outside of the can when the battery pack is manufactured as a battery pack, and then connecting the positive temperature element to the protection circuit board. Furthermore, since the positive temperature element is located outside of the can, the efficiency of breaking the current by rapidly reacting to the temperature of the can is not only low but also poorly connected to the surface of the can. There is also a problem that needs to be done.

The present invention is to overcome the above-mentioned conventional problems, an object of the present invention is to remove the positive electrode tab, the secondary that can increase the capacity by increasing the number of winding (area) of the electrode assembly by the volume occupied by the positive electrode tab It is to provide a battery.

Another object of the present invention is to provide a secondary battery capable of greatly increasing the height (area) of the electrode assembly by forming a negative electrode tab on a short side of the electrode assembly and bending the upper portion and connecting the electrode tab with the conductive member. have.

Another object of the present invention is to directly weld one electrode plate of the electrode assembly to the can, thereby providing a secondary battery capable of preventing the electrode assembly and the can directly electrically conducting, as well as the flow and noise of the electrode assembly in the can. It is.

Another object of the present invention is to pre-install a positive temperature element inside the can, thereby reacting sensitively to temperature and simplifying the manufacturing process of the secondary battery pack.

In order to achieve the above object, a secondary battery according to the present invention may be wound and received a plurality of times while a can in the form of a substantially hexahedron having an opening on one side, and a first electrode plate, a separator, and a second electrode plate laminated therein. The first electrode plate is directly connected to the inner surface of the can, and the electrode assembly is connected to the second electrode plate and is connected to a flexible wiring film having a positive temperature element extending a predetermined length to the outside, and a cap plate coupled to an opening of the can. The cap plate includes a cap assembly coupled with an electrode terminal to which the flexible wiring film is connected.

Here, the can has a pair of long side portions having a relatively large area and spaced apart from each other by a distance, a short side portion formed integrally with the long side portion with a relatively small area around both sides of the long side portion, and the long side portion as an opposite direction of the opening portion. And a bottom formed integrally with the short side.

In addition, a welding region may be further formed between the long side portion of the can and the first electrode plate of the electrode assembly to electrically and mechanically connect the electrode assembly to the can.

In addition, the flexible wiring film may include a positive temperature element for reducing a current by increasing a resistance value at a predetermined temperature or more, and a conductive wire having a predetermined length electrically connected to both ends of the positive temperature element to electrically connect the second electrode plate and the electrode terminal; , An insulating film surrounding the conductive wiring may be included.

In addition, one end of the flexible wiring film may be connected to a second electrode plate corresponding to the short side of the electrode assembly having a long side and a short side.

As described above, in the secondary battery according to the present invention, since the first electrode plate of the electrode assembly is directly and electrically welded to the can, there is no need for the positive electrode tab as in the prior art, and the electrode assembly flow and noise inside the can can be effectively prevented. You can do it.

In addition, in the secondary battery according to the present invention, since the positive electrode tab is removed, the process of connecting the positive electrode tab to the electrode assembly, the process of connecting the positive electrode tab to the cap plate, and the like can be omitted, thereby improving the productivity of the secondary battery.

In addition, the secondary battery according to the present invention is bent a predetermined angle while one end of the flexible wiring film is connected to the second electrode plate corresponding to the short side of the electrode assembly, and then the other end is connected to the electrode terminal, thereby connecting between the cap plate and the electrode assembly. The height can be greatly reduced. Conversely, it is possible to combine an electrode assembly with a higher height than conventionally in a can with the same height, thus further increasing the capacity.

In addition, in the secondary battery according to the present invention, the first and second insulating tapes are attached to the circumferences of the upper and lower ends of the electrode assembly, respectively, and the third insulating tape is also attached to the center of the upper end of the electrode assembly, thereby releasing and swelling the electrode assembly. The swelling can be suppressed efficiently.

In addition, in the secondary battery according to the present invention, since the positive temperature element is mounted on the flexible wiring film itself, it is not necessary to connect the positive temperature element separately during the battery pack manufacturing process, and the positive temperature element is positioned inside the can, It is sensitive to the temperature of the can to further improve the safety of the battery.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings such that those skilled in the art may easily implement the present invention.

1 is a perspective view of a rechargeable battery 300 according to the present invention.

As shown, the secondary battery 300 according to the present invention includes a can 310 having a substantially hexahedron shape, and a cap assembly 330 covering an upper portion of the can 310. Of course, the electrode assembly and the electrolyte is contained in the can 310, which will be described in detail below.

The can 310 includes a pair of long sides 311 having a relatively large area and spaced apart from each other by a predetermined distance. In addition, both sides of the long side portion 311 includes a short side portion 312 having a relatively small area and integrally formed with the long side portion 311. Further, a bottom portion 313 is integrally formed around the other side of the long side portion 311 and the short side portion 312.

In addition, the short side portion 312 may be formed with a predetermined curvature so as to be similar to the winding shape of the electrode assembly to be described below so that there is almost no empty space inside the can 310. Of course, the short side portion 312 may be formed at a right angle with respect to the long side portion 311, in the present invention is not limited to the shape of the short side portion 312.

The can 310 may be formed by any one selected from aluminum (Al), steel (Fe), stainless steel (SUS), copper (Cu), copper alloy (Cu alloy), or equivalents thereof. It does not limit the material.

The can 310 is mechanically and electrically connected and fixed to the electrode assembly to which the long side portion 311 is to be described. In addition, although the welding region 315 may be formed in an area where the diagonal lines intersect with each other of the long side portion 311, the can 310 is not limited to the position where the welding region 315 is formed. That is, the welding region 315 can be formed at any position of the long side portion 311. In addition, although the welding region 315 is formed in a substantially rectangular shape in the drawing, the present invention is not limited to this shape. That is, in the present invention, the welding region 315 may be formed in various shapes such as a circle, a triangle, and a plurality of point shapes in addition to the quadrangle. In addition, the welding region 315 may be formed by ultrasonic welding, laser welding, resistance welding, or an equivalent method, and the present invention does not limit the welding method.

On the other hand, the cap assembly 330 is coupled to the upper portion of the can 310 to prevent the electrode assembly and the electrolyte to be separated from the outside. That is, the cap plate 334 having a shape similar to the bottom portion 313 is coupled to a direction opposite to the bottom portion 313 of the can 310. The electrode terminal 336 is coupled to the center of the cap plate 334 with an insulating gasket 335 interposed to prevent a short. In addition, one side of the electrode terminal 336 is bonded and fixed to the ball 337 to prevent leakage of the electrolyte after the injection of the electrolyte, the other side has a relatively thin thickness to rupture when the internal pressure of the can 310 rises A safety vent 334c is formed to ensure safety. Of course, the safety vent 334c may be formed in a predetermined shape at a predetermined position among the long side portion 311, the short side portion 312, or the bottom portion 313 of the can 310 as well as the cap plate 334. In the present invention, the position and shape of the safety vent 334c are not limited.

2 is an exploded perspective view illustrating a rechargeable battery 300 according to the present invention.

As shown, a can 310 having a long side portion 311, a short side portion 312, and a bottom portion 313 having a welding area 315 at the center thereof is disposed in an electrode assembly opposite to the bottom portion 313. An opening 314 is formed so that the 320 can be easily inserted and coupled.

In addition, the electrode assembly 320 coupled to the inside of the can 310 through the opening 314 is slightly smaller than the height of the can 310 to secure an assembly space of the cap assembly 330. It is wound up in the form of a jelly roll having a long side 321 and a short side 322. In addition, the flexible wiring film 326 is formed by extending a predetermined distance from the short side 322 of the electrode assembly 320 upwardly and bending at a predetermined angle. The flexible wiring film 326 includes a conductive wiring 326a, an insulating film 326b surrounding the conductive wiring 326a, and a positive temperature element 326c formed between the conductive wiring 326a. Thus, since the flexible wiring film 326 is made of a thin conductive wiring 326a and an insulating film 326b, the flexible wiring film 326 can be easily bent in any direction. In addition, since the surface is insulating, it is not necessary to perform a separate insulating treatment. In addition, the flexible wiring film 326 is further formed with a positive temperature element 326c which also increases the resistance value when the temperature increases, thereby blocking the flow of current when the internal temperature of the can 310 abnormally increases. Battery safety is improved.

As described above, according to the present invention, only one flexible wiring film 326 is connected to the electrode assembly 320, thereby increasing the number of windings of the electrode assembly 320, that is, the area. Furthermore, since the flexible wiring film 326 can be easily bent in any direction without unnecessary electrical short with other components, the height (area) of the electrode assembly 320 can be greatly increased as compared with the related art. It becomes possible. Therefore, according to the present invention, it is possible to obtain the secondary battery 300 having the same size as the conventional can 310 and having an increased capacity.

In addition, the first and second insulating tapes 127a and 127b are formed on the upper and lower ends of the electrode assembly 320 to be integrally bonded to the long side 321 and the short side 322, respectively. In addition, since the flexible wiring film 326 is positioned on the short side 322, the third insulating tape 127c may be adhered to the long sides 321 of the electrode assembly 320 from the top of the center. Accordingly, the electrode assembly 320 is not easily released during the bonding process to the can 310, and also effectively suppresses the swelling during charging and discharging. Of course, the first, second, and third insulating tapes 127a, 127c, and 127c may have an empty space between the can 310 and the electrode assembly 320 when the electrode assembly 320 is coupled to the can 310. By almost eliminating this, the flow of the electrode assembly 320 and the noise caused by the inside of the can 310 can be effectively suppressed.

Here, the predetermined region of the electrode assembly 320 to which the flexible wiring film 326 is connected is shown in a partially cut state.

Subsequently, a welding region 329 electrically and mechanically connected to the can 310 is also formed at the long side 321 of the electrode assembly 320 corresponding to the long side portion 311 of the can 310.

On the other hand, the cap assembly 330 is generally located above the electrode assembly 320. That is, the electrode terminal 336 coupled with the insulating case 331, the terminal plate 332, the insulating plate 333, the cap plate 334, and the insulating gasket 335 is sequentially formed from the bottom. In addition, the insulating case 331 is formed with a cutout groove 331a having a predetermined size in an area corresponding to the short side portion 312 of the can 310, so that the flexible wiring film 326 can easily pass. In addition, an electrolyte injection hole 331b is also formed at one side so that the electrolyte can be easily injected.

In addition, through holes 332a, 333a, and 334a are formed in the terminal plate 332, the insulating plate 333, and the cap plate 334 so that the electrode terminals 336 are easily coupled to each other. Of course, the cap plate 334 is formed with an electrolyte injection hole 334b for electrolyte injection, and a ball 337 is welded to the electrolyte injection hole 334b. In addition, as described above, a safety vent 334c having a predetermined shape is formed to rupture when the internal voltage of the battery increases to ensure safety.

FIG. 3 is an enlarged perspective view illustrating a region of FIG. 2.

As shown in the drawing, the electrode assembly 320 is wound a plurality of times with the first electrode plate 323, the separator 324, and the second electrode plate 325 stacked in an outward direction. Of course, the flexible wiring film 326 is connected to the second electrode plate 325 of the short side 322 of the electrode assembly 320. That is, one end of the conductive wiring 326a is electrically connected to the second electrode plate 325.

In addition, the electrode assembly 320 is exposed to the first electrode plate 323 is located at the outermost. Accordingly, the first electrode plate 323 may be electrically and mechanically connected directly to the can 310. Although not shown, the height of the separator 324 is slightly larger than the height of the first electrode plate 323 and the second electrode plate 325. Therefore, the electrical short phenomenon that may occur at the upper end or the lower end of the first electrode plate 323 and the second electrode plate 325 is effectively prevented by the separator 324.

Here, the first electrode plate 323 may be a conventional aluminum foil, the positive electrode active material (for example, lithium cobalt (LiCoO ₂ ), lithium nickel (LiNiO ₂ ), lithium manganate (LiMn _{2) on the surface} O ₄ ) or equivalent thereof) may be coated. In addition, the separator 324 may be polyethylene (PE) or polypropylene (PP). In addition, the second electrode plate 325 may be a copper foil, and a negative electrode active material (eg, graphite or an equivalent thereof) may be coated on a surface thereof. Accordingly, the first electrode plate 323 generally has a positive electrode property, and the second electrode plate 325 has a generally negative electrode property. However, the metal type and the active material type of the first electrode plate 323 and the second electrode plate 325 are not limited thereto. That is, the first electrode plate 323 may be a cathode generally, and the second electrode plate 325 may be an anode generally.

Further, the cathode active material is not formed in the outermost region of the first electrode plate 323 in contact with the inside of the can 310 for easy welding with the can 310. Of course, the outermost region of the first electrode plate 323 is a region that does not chemically react with the second electrode plate 325, and thus it is not necessary to form a cathode active material.

4 is a cross-sectional view taken along the line 2-2 of FIG.

As shown, the flexible wiring film 326 includes a positive temperature element 326c that blocks the current by increasing the resistance value with increasing temperature. Of course, conductive wires 326a are connected to both ends of the positive temperature element 326c, respectively, but one end of the positive temperature element 326c is connected to the second electrode plate 325 of the electrode assembly 320, and the other end of the electrode It is connected to the terminal 336. Accordingly, the positive temperature element 326c can efficiently control the current flowing from the second electrode plate 325 to the electrode terminal 336 or from the electrode terminal 336 to the second electrode plate 325.

That is, in the case of the secondary battery, the internal temperature generally rises rapidly when the overcharge or overdischarge current flows. Of course, due to such a rapid rise in the internal temperature, the active material or the electrolyte is decomposed to generate gas, and the swelling (can swelling phenomenon) is caused by the gas. In addition, if the internal pressure of the can 310 continues to increase, the safety vent 334c formed at the cap plate 334 or other positions may be ruptured, thereby preventing the risk of a large explosion or fire of the secondary battery. However, such a safety vent 334c, once operated, it is difficult to normally use the secondary battery again and should usually be discarded.

Therefore, when the positive temperature element 326c is installed in the path of the charging or discharging current as described above, the charge / discharge current is lowered or blocked at the time of overcharge or overdischarge (that is, when the temperature inside the battery increases). It will suppress the temperature increase. Of course, when the temperature increase stops, the internal pressure usually decreases again, and the swelling phenomenon also stops.

In addition, since the positive temperature element 326c operates reversibly, when the internal temperature of the can 310 returns to normal, the current passing through the positive temperature element 326c also becomes normal. In other words, the resistance value of the positive temperature element 326c becomes smaller again.

Referring to FIG. 5, a cross-sectional view taken along line 3-3 of FIG. 1 is shown.

As illustrated, a first insulating tape 327a is adhered to an upper end of the can 310 of the can 310 as a short side 322 of the electrode assembly 320 corresponding to the short side 312. Of course, the first insulating tape 327a is integrally bonded to the long side 321 of the electrode assembly 320. Accordingly, the short side 322 and the long side 321 of the electrode assembly 320 are tightly adhered to the short side 312 and the long side 311 of the can 310 and do not flow. In addition, the flexible wiring film 326 is connected to the short side 322 of the electrode assembly 320 and is bent toward the electrode terminal 336 while passing through the cut groove 331a of the insulating case 331. . Of course, the flexible wiring film 326 is electrically connected to the electrode terminal 336. This electrical connection may be made of a conductive member 338, such as a solder or anisotropic conductive film. Of course, electrical connection by conventional resistance welding, laser welding or ultrasonic welding is also possible, and the present invention does not limit the form of electrical connection between the flexible wiring film 336 and the electrode terminal 336. In this case, the positive temperature element 326c formed in the flexible wiring film 326 is approximately positioned on the top surface of the insulating case 331. Therefore, even if the thickness of the positive temperature element 326c is relatively thick, the volume of the electrode assembly 320 is not increased.

Meanwhile, an electrode terminal 336 is coupled to the cap plate 334 of the cap assembly 330 through an insulating gasket 335, and the electrode terminal 336 is connected to the flexible wiring film 326.

Of course, the electrode terminal 336 is coupled with the insulating plate 333 and the terminal plate 332 penetrating through the lower portion of the cap plate 334, so that the electrode terminal 336 is not separated from the cap plate 334. It is supposed to be.

FIG. 6 is an enlarged cross-sectional view of four areas of FIG. 5.

As illustrated, the flexible wiring film 326 is connected to the short side 322 of the electrode assembly 320 and the second electrode plate 325 of the corresponding region. More specifically, the conductive wiring 326a of the flexible wiring film 326 is welded to the second electrode plate 325. In addition, since the insulating film 326b is formed on the surface of the conductive wiring 326a, unnecessary short with the first electrode plate 323 is prevented. Of course, since the separator 324 is interposed between the first electrode plate 323 and the second electrode plate 325, the above-described short does not occur even if the insulating film 326b is not present. As described above, the negative electrode active material is not formed on the second electrode plate 325 to which the conductive wiring 326a of the flexible wiring film 326 is welded.

 Meanwhile, in the drawing, the flexible wiring film 326 is connected to the first electrode plate 323 and the second electrode plate 325 positioned inside the separator 324 at the outermost part of the electrode assembly 320. However, the present invention is not limited to this structure. That is, the flexible wiring film 326 may be connected to the second electrode plate 325 located further inward.

FIG. 7 is an enlarged cross-sectional view of five regions of FIG. 5.

As illustrated, the flexible wiring film 326 is positioned between the lower surface of the electrode terminal 336 and the upper surface of the insulating case 331. More specifically, the conductive wiring 326a of the flexible wiring film 326 is positioned between the electrode terminal 336 and the insulating case 331. In addition, the conductive wire 326a is electrically connected to the electrode terminal 336 by a conductive member 338. As described above, the conductive member 338 may be a solder, an anisotropic conductive film, or an equivalent thereof, but the material is not limited thereto. Of course, the conductive wire 326a may be directly connected to the electrode terminal 336 by resistance welding, laser welding, ultrasonic welding, or an equivalent member without the conductive member.

By the above structure, the electrode terminal 336 has the same polarity as the second electrode plate 325. For example, if the second electrode plate 325 is a cathode, the flexible wiring film 326 is also a cathode, and thus the electrode terminal 336 connected thereto is also a cathode. On the contrary, if the second electrode plate 325 is an anode, the electrode terminal 336 is also an anode.

On the other hand, a positive temperature element 326c is formed on the flexible wiring film 326 positioned on the upper surface of the insulating case 331 as shown. Therefore, even if the thickness of the positive temperature element 326c is larger than the thickness of the flexible wiring film 326, the thickness of the positive temperature element 326c is smaller than the height of the space between the cap plate 334 and the insulating case 331, which is not a big problem. That is, the battery capacity is not reduced without reducing the height or area of the electrode assembly.

8 is a cross-sectional view taken along line 6-6 of FIG.

As shown in the drawing, the welding regions 329 may be formed in the long sides 311 formed in the mutually opposite directions of the can 310. Accordingly, the electrode assembly 320 is electrically and mechanically fixed to both the long sides 311 positioned at both sides, thereby taking a stable fixing structure and effectively preventing flow and noise phenomena. In addition, the welding region 329 may be formed at approximately the center of the corresponding long side portions 311, so that the electrode assembly 320 may be stably fixed to the can 310 in opposite directions. However, the welding region 329 is not limited to this form, and in some cases, the welding region 329 may be formed in an asymmetrical form. That is, the welding region 329 formed between the long side portion 311 and the electrode assembly 320 on one side and the welding region 329 formed between the long side portion 311 and the electrode assembly 320 on the other side are asymmetric with each other. And asymmetrical shapes.

The welding region 329 may be formed by further interposing a separate member instead of forming the long side portion 311 and the electrode assembly 320 of the can 310 by mutual melting. For example, the solder paste may be interposed between the can 310 and the electrode assembly 320 and then reflowed at a predetermined temperature (about 150 to 250 ° C.), thereby providing the solder paste. While melting is possible, a structure for mechanically and electrically connecting the can 310 and the electrode assembly 320 is possible, and this method is not excluded from the present invention.

9 is an enlarged cross-sectional view of area 7 of FIG. 8.

As illustrated, the first electrode plate 323 of the electrode assembly 320 is directly welded to the long side portion 311 of the can 310. That is, a welding region 329 is formed between the first electrode plate 323 and the long side portion 311 of the can 310. Of course, a separator 324 is interposed inside the first electrode plate 323, and a second electrode plate 325 to which a flexible wiring film (not shown) is connected is formed inside the first electrode plate 323. There is no fear that the first electrode plate 323 and the second electrode plate 325 are shorted to each other. In addition, when the welding using the ultrasonic method, the melting depth is small, it is possible to further reduce the short probability. That is, in the state where the electrode assembly 320 is inserted into the inside of the can 310, the long side portion 311 is applied to the predetermined position among the long side portions 311 of the can 310 so that the long side portion 311 makes the electrode assembly. The first electrode plate 323 of the 320 may be welded. However, the present invention does not limit welding in such an ultrasonic manner, and conventional laser welding, resistance welding, or an equivalent method thereof may be used.

In addition, since the first electrode plate 323 is directly welded to the can 310, the can 310 and the cap plate 334 have the same polarity as the first electrode plate 323. For example, if the first electrode plate 323 is a positive electrode, the can 310 and the cap plate 334 may also be an anode. If the first electrode plate 323 is a cathode, the can 310 and the cap plate 334 also become cathodes.

10 is a cross-sectional view taken along line 8-8 of FIG. 1.

As shown, the can 310 includes a long side portion 311 spaced a predetermined distance from each other, and a short side portion 312 formed around the can. Here, the short side portion 312 may be formed having a predetermined curvature. Accordingly, since the short side 322 of the electrode assembly 320 is also wound with a predetermined curvature, there is almost a gap between the short side 312 of the can 310 and the short side 322 of the electrode assembly 320. You will not. Further, although not shown in the drawing, the short sides 322 of the electrode assembly 320 are further bonded to the first and second insulating tapes 327a and 227b (see FIG. 2), and thus, the short sides of the can 310. Since there is almost no gap between the 312 and the short side 322 of the electrode assembly 320, it is possible to efficiently prevent the flow and noise phenomenon of the electrode assembly 320 inside the can 310.

In addition, the long side 321 of the electrode assembly 320 is welded to the long side 311 of the can 310. In other words, a welding region 329 is formed between the long side 321 of the first electrode plate 323 and the long side portion 311 of the can 310 of the electrode assembly 320. The welding region 329 serves to fix the electrode assembly 320 to the can 310 electrically as well as mechanically. Therefore, the voltage and current by the first electrode plate 323 of the electrode assembly 320 are transferred to the can 310 as it is, and the electrode assembly 320 does not flow inside the can 310.

As described above, in the secondary battery according to the present invention, since the first electrode plate of the electrode assembly is directly and electrically welded to the can, there is no need for the positive electrode tab as in the prior art, and the flow and noise of the electrode assembly inside the can can be efficiently It can be prevented.

In addition, in the secondary battery according to the present invention, since the positive electrode tab is removed, the process of connecting the positive electrode tab to the electrode assembly, the process of connecting the positive electrode tab to the cap plate, and the like can be omitted, thereby improving the productivity of the secondary battery.

In addition, the secondary battery according to the present invention is bent a predetermined angle while one end of the flexible wiring film is connected to the second electrode plate corresponding to the short side of the electrode assembly, and then the other end is connected to the electrode terminal, thereby connecting between the cap plate and the electrode assembly. The height can be greatly reduced. Conversely, it is possible to combine an electrode assembly with a higher height than conventionally in a can with the same height, thus further increasing the capacity.

In addition, in the secondary battery according to the present invention, the first and second insulating tapes are attached to the circumferences of the upper and lower ends of the electrode assembly, respectively, and the third insulating tape is also attached to the center of the upper end of the electrode assembly, thereby releasing and swelling the electrode assembly. The swelling can be suppressed efficiently.

In addition, in the secondary battery according to the present invention, since the positive temperature element is mounted on the flexible wiring film itself, it is not necessary to connect the positive temperature element separately during the battery pack manufacturing process, and the positive temperature element is positioned inside the can, It is sensitive to the temperature of the can to further improve the safety of the battery.

What has been described above is only one embodiment for carrying out the secondary battery according to the present invention, and the present invention is not limited to the above-described embodiment, and the present invention deviates from the gist of the present invention. Without this, anyone skilled in the art to which the present invention pertains will have the technical spirit of the present invention to the extent that various modifications can be made.

Claims (19)

A can of a hexahedron shape having an opening on one side; The first electrode plate, the separator, and the second electrode plate are stacked and wound a plurality of times inside the can, and the first electrode plate is directly connected to the inner surface of the can, and the second electrode plate extends outside. An electrode assembly to which a flexible wiring film having a positive temperature element is connected; And, The cap plate is coupled to the opening of the can, the cap plate comprises a cap assembly comprising an electrode terminal to which the flexible wiring film is connected. The method of claim 1, wherein the can has a relatively large area and a pair of long sides spaced apart from each other, a short side portion formed integrally with the long side portion having a relatively small area around both sides of the long side portion, A secondary battery comprising a bottom portion integrally formed with the long side portion and the short side portion in the opposite direction of the opening portion. The secondary battery of claim 2, wherein the short side portion is formed to have a curvature. The secondary battery of claim 2, wherein the short side portion is formed at a right angle with respect to the long side portion. The secondary battery of claim 2, wherein the long side portion of the can is directly connected to the first electrode plate of the electrode assembly. The secondary battery of claim 2, further comprising a welding region between the long side of the can and the first electrode plate of the electrode assembly to electrically and mechanically connect the electrode assembly to the can. The secondary battery of claim 2, wherein the long side portion of the can is connected to the first electrode plate of the electrode assembly in a region where the diagonal crosses. The secondary battery of claim 1, wherein the can is formed of any one selected from aluminum, steel, stainless steel, copper, or a copper alloy. The flexible wiring film of claim 1, wherein the flexible wiring film has a positive temperature element that increases resistance and decreases current when the temperature increases, and is connected to both ends of the positive temperature element so as to electrically conduct the second electrode plate and the electrode terminal. A secondary battery comprising a conductive wiring having a length and an insulating film surrounding the conductive wiring. The secondary battery of claim 1, wherein the electrode assembly is wound in a jelly roll having a long side and a short side, and one end of the flexible wiring film is connected to a region corresponding to a short side of the second electrode plate. 11. The method of claim 10, wherein the first and second insulating tapes covering the long side and the short side at the same time is bonded to the upper and lower ends of the electrode assembly, and the third insulating tape is adhered from one long side to the other long side as the upper end of the electrode assembly. Secondary battery, characterized in that. The secondary battery of claim 10, wherein the flexible wiring film extends to a lower end of the electrode terminal while being bent at a right angle at an upper end of a short side of the electrode assembly. The secondary battery according to claim 1, wherein a conductive member is interposed between the flexible wiring film and the electrode terminal. The secondary battery of claim 1, wherein the electrode terminal is coupled to the cap plate with an insulating gasket interposed therebetween. The secondary battery of claim 10, wherein the cap assembly further includes an insulating case between the cap plate and the electrode assembly. The method of claim 15, wherein the insulating case has a cutout groove having a predetermined size so that the flexible wiring film can pass through a region corresponding to the short side of the electrode assembly, and the positive temperature element formed in the flexible wiring film is insulated from the insulating case. A secondary battery, characterized in that located on the upper surface of the case. The secondary battery of claim 1, wherein the first electrode plate of the electrode assembly is coated with a positive electrode active material, and the second electrode plate is coated with a negative electrode active material. The secondary battery of claim 1, wherein an electrolyte inlet for injecting an electrolyte is formed in a cap plate of the cap assembly, and a ball is inserted into and welded to the electrolyte inlet. The secondary battery of claim 1, wherein the cap plate of the cap assembly has a safety vent formed at a relatively thin thickness and ruptured when the internal pressure increases.

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