Title of invention: secondary battery
Technical field
[One]
Mutual citation with related applications
[2]
This application claims the benefit of priority based on Korean Patent Application No. 10-2018-0118865 filed on October 05, 2018, and all contents disclosed in the documents of the Korean patent application are included as part of this specification.
[3]
Technical field
[4]
The present invention relates to a secondary battery.
Background
[5]
Unlike primary batteries, secondary batteries can be recharged, and due to their small size and high capacity, many research and developments have been made in recent years. 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 power plant capable of charging and discharging having a stacked structure of electrodes and separators.
[7]
The electrode assembly is a jelly-roll type in which a separator is interposed between the positive electrode and the negative electrode in a sheet type 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 may be roughly classified into a stack/folding type wound with a long-length separation film. The double jelly roll type electrode assembly is widely used because it is easy to manufacture and has a 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 capable of reducing resistance and temperature variation for each position of an electrode in a wound electrode assembly.
[9]
Another aspect of the present invention is to provide a secondary battery having excellent meandering alignment when winding an electrode assembly.
Means of solving the task
[10]
A secondary battery according to an embodiment of the present invention includes an electrode assembly in which a positive electrode, a separator, and a negative electrode are alternately stacked, and a can accommodating the electrode assembly, wherein the negative electrode includes a negative electrode uncoated portion not coated with a negative electrode active material, and the electrode Based on the winding central axis direction of the assembly, it is located at one end portion so as to protrude more than the separator, and the positive electrode has a positive electrode uncoated portion not coated with a positive electrode active material, based on the winding central axis direction of the electrode assembly, the separator It is located at the other end of the can so as to protrude further, the can includes a first can and a second can, the negative electrode uncoated portion directly contacts the inner surface of the first can, and the anode uncoated portion is an inner surface of the second can Can be in direct contact with.
Effects of the Invention
[11]
According to the present invention, since all the electrodes of the wound electrode assembly can be connected directly to the can in succession, resistance and temperature variation of each electrode can be reduced.
[12]
In addition, according to the present invention, when the electrode current collector is compressed to increase the welding area when the electrode is connected to the bottom surface of the can, the center pin provides a reference surface, so that welding quality and resistance deviation can be secured to a certain level.
[13]
In addition, according to the present invention, since the center pin is provided in the core portion of the electrode assembly in the secondary battery, it is possible to prevent the occurrence of cracking of the electrode positioned in the core portion of the electrode assembly as the charge/discharge cycle progresses.
[14]
Further, according to the present invention, as the electrode assembly is wound around the center pin, the meandering alignment of the electrode and the separator may be excellent.
[15]
In addition, according to the present invention, the cylindrical center pin may provide an electrolyte storage space before the electrode assembly is impregnated with the electrolyte, and a space for collecting internal gas according to the progress of the charge/discharge cycle may be provided.
Brief description of the drawing
[16]
1 is a cross-sectional view schematically showing a secondary battery according to a first embodiment of the present invention.
[17]
2 is a cross-sectional view illustrating another example of a can in the secondary battery according to the first embodiment of the present invention.
[18]
3 is a perspective view showing an electrode assembly in the secondary battery according to the first embodiment of the present invention.
[19]
4 is a cross-sectional view showing an electrode assembly in a secondary battery according to a first embodiment of the present invention.
[20]
5 is an exploded perspective view showing an unfolded state before winding an electrode assembly in the secondary battery according to the first embodiment of the present invention.
[21]
6 is a plan view showing an unfolded state before winding an electrode assembly in the secondary battery according to the first embodiment of the present invention.
[22]
7 is a cross-sectional view illustrating a secondary battery according to a second embodiment of the present invention.
[23]
8 is a perspective view showing an electrode assembly in a secondary battery according to a second embodiment of the present invention.
[24]
9 is a cross-sectional view showing an electrode assembly in a secondary battery according to a second embodiment of the present invention.
[25]
10 is an exploded perspective view showing an unfolded state before winding an electrode assembly in a secondary battery according to a second embodiment of the present invention.
[26]
11 is a plan view showing an unfolded state before winding an electrode assembly in a secondary battery according to a second embodiment of the present invention.
[27]
12 is a cross-sectional view showing a secondary battery according to a third embodiment of the present invention.
[28]
13 is a perspective view showing an electrode assembly in a secondary battery according to a third embodiment of the present invention.
[29]
14 is a cross-sectional view showing a secondary battery according to a fourth embodiment of the present invention.
[30]
15 is a perspective view showing an electrode assembly in a secondary battery according to a fourth embodiment of the present invention.
[31]
16 is a cross-sectional view showing a secondary battery according to a fifth embodiment of the present invention.
[32]
17 is a perspective view showing an electrode assembly in a secondary battery according to a fifth embodiment of the present invention.
[33]
18 is a cross-sectional view showing a secondary battery according to a sixth embodiment of the present invention.
Mode for carrying out the invention
[34]
Objects, specific advantages and novel features of the present invention will become more apparent from the following detailed description and preferred embodiments associated with the accompanying drawings. In the present specification, in adding reference numerals to elements of each drawing, it should be noted that only the same elements have the same number as possible, even if they are indicated on different drawings. In addition, the present invention may be implemented in various different forms and is not limited to the embodiments described herein. In addition, in describing the present invention, detailed descriptions of related known technologies that may unnecessarily obscure the subject matter of the present invention will be omitted.
[35]
[36]
1 is a cross-sectional view schematically showing a secondary battery according to a first embodiment of the present invention.
[37]
Referring to FIG. 1, the secondary battery 100 according to the first embodiment of the present invention includes an electrode assembly 110 in which a positive electrode 112, a separator 114, and a negative electrode 111 are alternately stacked, and a first can ( It is composed of a can 120 that accommodates the electrode assembly 110 including the 121 and the second can 122, the negative electrode uncoated portion 111c contacts the first can 121, and the anode uncoated portion 112c ) Contacts the inner surface of the second can 122.
[38]
[39]
Hereinafter, a secondary battery according to a first embodiment of the present invention will be described in more detail with reference to FIGS. 1 to 6.
[40]
Referring to FIG. 1, the secondary battery 100 includes an electrode assembly 110 and a can 120 accommodating the electrode assembly 110. Here, the secondary battery 100 may further include an electrolyte solution accommodated in the can 120 together with the electrode assembly 110.
[41]
[42]
2 is a cross-sectional view illustrating another example of a can in the secondary battery according to the first embodiment of the present invention.
[43]
The can 120 may include the first can 121 and the second can 122 to accommodate the electrode assembly 110 therein.
[44]
In addition, the end of the cathode 111 may be connected to the first can 121 and the end of the anode 112 may be connected to the end of the second can 122, but the present invention is not necessarily limited thereto. , For example, the end of the anode 112 may be connected to the first can 121 and the end of the cathode 111 may be connected to the second can 122. In this case, the first can 121 may have a negative potential by connecting the cathode 111, and the second can 122 may have a positive potential by connecting the anode 112. Here, the first can 121 may be made of, for example, steel, and the second can 122 may be made of, for example, aluminum (Al).
[45]
[46]
In FIG. 1, the first can 121 and the second can 122 are shown to be positioned only on the upper and lower portions of the electrode assembly 110, but this is an exemplary example of the can 120 in the secondary battery 100. 2, as another example of the can 120 ′ in the secondary battery 100 ′, as shown in FIG. 2, the first can 121 ′ and the second can 122 ′ face each other. It may be formed in an open cylindrical shape. In this case, the can 120 ′ may further include an insulator 123 ′ that insulates an overlapping portion between the first can 121 ′ and the second can 122 ′.
[47]
[48]
3 is a perspective view showing an electrode assembly in a secondary battery according to a first embodiment of the present invention, and FIG. 4 is a cross-sectional view showing an electrode assembly in a secondary battery according to the first embodiment of the present invention.
[49]
In addition, FIG. 5 is an exploded perspective view showing an unfolded state before winding an electrode assembly in the secondary battery according to the first embodiment of the present invention, and FIG. 6 is a winding electrode assembly in the secondary battery according to the first embodiment of the present invention. It is a plan view showing the unfolded state before doing so.
[50]
3 and 4, the electrode assembly 110 is a power generating device capable of charging and discharging, and the electrode 113 and the separator 114 are assembled to form a structure in which the electrode 113 and the separator 114 are alternately stacked. Here, the electrode assembly 110 may have a wound shape.
[51]
3 to 6, the electrode 113 may include an anode 112 and a cathode 111. In addition, the separator 114 separates and electrically insulates the anode 112 and the cathode 111. Here, the positive electrode 112 and the negative electrode 111 may be formed in a sheet shape, wound together with the separator 114, and formed in a jelly roll type. In this case, the electrode assembly 110 may be wound in a cylindrical shape, for example. In addition, the anode 112, the separator 114, and the cathode 111 are each of a plurality of layers in the thickness direction of the electrode assembly 110 perpendicular to the winding central axis C of the electrode assembly 110. Can be formed.
[52]
4 and 5, the negative electrode 111 may include a negative electrode current collector 111a and a negative electrode active material 111b applied to the negative electrode current collector 111a.
[53]
In addition, the negative electrode 111 may have a negative electrode uncoated portion 111c, which is a region in which the negative electrode active material 111b is not applied to the negative electrode current collector 111a.
[54]
The negative electrode uncoated portion 111c may be positioned at an end portion in the direction of one side (C1) so as to protrude more than the separator 114 with respect to, for example, the direction of the winding central axis C of the electrode assembly 110.
[55]
In addition, the negative electrode uncoated portion 111c may be formed on the entire end of one side of the negative electrode 111 along the winding direction.
[56]
In addition, the negative electrode uncoated portion 111c may be formed to extend from the winding central axis C of the electrode assembly 110 in the direction of one side (C1) than the end portion of the positive electrode 112. That is, for example, when referring to the matters shown in FIG. 1, the end of the negative electrode current collector 111a in the negative electrode uncoated portion 111c may be formed to protrude more toward the top of the electrode assembly 110 than the positive electrode 112 I can. Accordingly, the first can 121 may form a negative terminal by being in direct contact with the inner upper surface of the first can 121 positioned on the upper side. Accordingly, compared to that the end of the cathode 111 is in direct contact with the first can 121 and is connected through a separate connection line, the resistance is significantly reduced. By lowering the value, deterioration of cell performance due to deterioration can be prevented.
[57]
The negative electrode current collector 111a may be made of a foil made of, for example, copper (Cu) or nickel (Ni). The negative active material 111b may be made of, for example, artificial graphite, lithium metal, lithium alloy, carbon, petroleum coke, activated carbon, graphite, silicon compound, tin compound, titanium compound, or alloys thereof. In this case, the negative active material 111b may further include, for example, non-graphitic silicon (SiO) or silicon carbide (SiC).
[58]
[59]
4 and 5, the positive electrode 112 may include a positive electrode current collector 112a and a positive electrode active material 112b applied to the positive electrode current collector 112a.
[60]
In addition, the positive electrode 112 may have a positive electrode blank 112c, which is a region in which the positive electrode active material 112b is not applied, on the positive electrode current collector 112a.
[61]
The anode blank 112c may be positioned at an end portion in the other side (C2) direction so as to protrude more than the separator 114 based on the winding central axis (C) direction of the electrode assembly 110.
[62]
In addition, the anode uncoated portion 112c may be formed on the entire other end of the anode 112 along the winding direction.
[63]
In addition, the anode uncoated portion 112c may be formed to extend from the winding central axis C of the electrode assembly 110 in the direction of one side (C1) than the end of the cathode 111. That is, when referring to the matter shown in FIG. 1, for example, the end of the positive electrode current collector 112a in the positive electrode uncoated portion 112c region is formed to protrude further toward the lower side of the electrode assembly 110 than the negative electrode 111. I can. Thus, for example, the second can 122 may form a positive terminal by directly contacting the inner lower surface of the second can 122 positioned below. Accordingly, compared to that the end of the anode 112 is in direct contact with the second can 122 and is connected through a separate connection line, resistance is significantly reduced. By lowering the value, deterioration of cell performance due to deterioration can be prevented.
[64]
As described above, in the secondary battery according to the first embodiment of the present invention, all the electrodes 113 of the electrode assembly 110 can be connected directly to the can 120 continuously, thereby reducing the resistance and temperature deviation of the electrode 113 by position. I can.
[65]
The positive electrode current collector 112a may be made of, for example, an aluminum foil, and the positive electrode active material is, for example, lithium manganese oxide, lithium cobalt oxide, lithium nickel oxide, lithium iron phosphate, or at least one of these It may be made of a compound and a mixture containing this.
[66]
[67]
3 and 4, the separator 114 is made of an insulating material and is alternately stacked with the anode 112 and the cathode 111. Here, the separator 114 may be positioned between the anode 112 and the cathode 111 and on the outer surfaces of the anode 112 and the cathode 111. In this case, the separator 114 may be positioned at the outermost side in the width direction when the electrode assembly 110 is wound.
[68]
In addition, the separation membrane 114 may be made of a flexible material. At this time, the separator 114 may be formed of a polyolefin-based resin film such as polyethylene or polypropylene having microporous properties.
[69]
[70]
Hereinafter, a secondary battery according to a second embodiment will be described.
[71]
7 is a cross-sectional view illustrating a secondary battery according to a second embodiment of the present invention.
[72]
Referring to FIG. 7, the secondary battery 200 according to the second embodiment of the present invention includes an electrode assembly 210 in which an anode 212, a separator 214, and a cathode 211 are alternately stacked, and a first can. It includes a can 220 that accommodates the electrode assembly 210 including the 221 and the second can 222 and a center pin 230 positioned at the center of the winding of the electrode assembly 210, and a negative electrode uncoated portion ( 211c) contacts the first can 221, and the anode uncoated portion 212c contacts the inner surface of the second can 222.
[73]
The secondary battery 200 according to the second embodiment of the present invention has a difference in that it further includes a center pin 230 as compared to the secondary battery according to the first embodiment described above. Accordingly, in the present embodiment, contents overlapping with the first embodiment will be briefly described, and the differences will be mainly described.
[74]
[75]
8 is a perspective view illustrating an electrode assembly in a secondary battery according to a second embodiment of the present invention, and FIG. 9 is a cross-sectional view illustrating an electrode assembly in a secondary battery according to a second embodiment of the present invention.
[76]
In addition, FIG. 10 is an exploded perspective view showing an unfolded state before winding an electrode assembly in a secondary battery according to a second embodiment of the present invention, and FIG. 11 is a winding electrode assembly in the secondary battery according to the second embodiment of the present invention. It is a plan view showing the unfolded state before doing so.
[77]
8 to 11, in the secondary battery 200 according to the second embodiment of the present invention, the center pin 230 is located at the center of the winding of the electrode assembly 210, and the reference when the electrode assembly 210 is wound. An axis or reference plane can be provided. Here, the electrode assembly 210 may surround the center pin 230 and may be wound around the center pin 230. Accordingly, when the anode 212, the separator 214, and the cathode 211 are wound, the meandering alignment of the anode 212, the separator 214, and the cathode 211 is captured through the center pin 230. (For reference, meandering refers to the phenomenon of curling obliquely rather than evenly during winding).
[78]
In addition, the center pin 230 is provided in the core portion, which is the center of the electrode assembly 210, to prevent the occurrence of cracking of the electrode 113 located in the core portion of the electrode assembly 210 as the charge/discharge cycle progresses. Can be prevented.
[79]
In addition, the anode 212, the separator 214, and the cathode 211 are wound around the outer circumferential surface of the center pin 230, and the electrode assembly 210 perpendicular to the winding central axis C of the electrode assembly 210 It is possible to form a plurality of layers, respectively, in the thickness direction of.
[80]
In addition, the electrode assembly 210 may be wound while being fixed to the center pin 230 with a tape 240 (see FIG. 11 ). If the tape fixing method is used, the meandering alignment during winding can be improved.
[81]
In addition, the center pin 230 may be formed of an insulating material.
[82]
In addition, the center pin 230 may be provided in a cylindrical shape in which the center side is empty with respect to the central axis.
[83]
In addition, the center pin 230 may have a thickness of, for example, 0.1 to 1 mm. Here, the center pin 230 may have a specific thickness of, for example, 0.2 to 0.5 mm.
[84]
In addition, the outer diameter d1 of the center pin 230 may be formed to be 5 to 30% of the outer diameter d2 of the electrode assembly 210. In this case, the outer diameter d1 of the center pin 230 may be specifically formed to be 10 to 20% of the outer diameter d2 of the electrode assembly 210, for example.
[85]
In addition, the length of the center pin 230 is to be formed shorter than the length from one end of the cathode uncoated portion 211c to the other end of the anode uncoated portion 212c in the direction of the winding central axis (C) of the electrode assembly 210. I can. Here, the cathode uncoated portion 211c is formed to extend longer in the direction of one side (C1) than the center pin 230 with respect to the winding central axis (C), and the anode uncoated portion 212c extends along the winding central axis (C). As a reference, it may be formed to extend longer in the direction of the other side (C2) than the center pin 230. In this case, the length of the separator 214 in the direction of the central axis C of winding of the electrode assembly 210 may be formed equal to the length of the center pin 230.
[86]
In addition, one side of the center pin 230 may be in surface contact with the inner surface of the first can 221, and the other side of the center pin 230 may be in surface contact with the inner surface of the second can 222.
[87]
In the secondary battery 200 according to the second embodiment of the present invention, configured as described above, the negative electrode uncoated portion 211c is more than the separator 214 based on the winding central axis C direction of the electrode assembly 210. The center pin 230 is located at the end in one direction so as to protrude, is located at the end in the other side (C2) direction so that the anode uncoated part 212c protrudes more than the separator 214, and is located at the center of the winding of the electrode assembly 210 The length of is formed to be shorter than the length from one end of the negative uncoated portion 211c to the other end of the positive uncoated portion 212c.
[88]
Therefore, in a form in which the negative electrode uncoated portion 211c is in contact with the first can 221 and the positive uncoated portion 212c is in contact with the inner surface of the second can 222, the negative electrode current collector 111b is ) And the positive electrode current collector 112a, the center pin 230 provides a reference surface, so that welding quality and resistance deviation can be secured to a certain level. That is, when the first can 221 and the second can 222 are pressed in a direction facing each other, when the center pin 230 is pressed to the location, the positive electrode is more protruded than the center pin 230. The protruding portions of the portion 212c and the negative electrode uncoated portion 211c are bent (see FIG. 7 ), so that the inner surfaces of the first can 221 and the second can 222 are evenly in direct contact. Accordingly, when welding the ends of the anode 212 and the cathode 211 on the inner surface of the can 220, welding quality is improved, and resistance deviation can be secured to a certain level.
[89]
[90]
Hereinafter, a secondary battery according to a third embodiment will be described.
[91]
12 is a cross-sectional view showing a secondary battery according to a third embodiment of the present invention.
[92]
12 and 13, the secondary battery 300 according to the third embodiment of the present invention includes an electrode assembly 310 in which an anode 312, a separator 314, and a cathode 311 are alternately stacked, Including the can 320 accommodating the electrode assembly 310 including the first can 321 and the second can 322 and a center pin 330 positioned at the center of the winding of the electrode assembly 310, the cathode The uncoated portion 311c contacts the first can 321, and the anode uncoated portion 312c contacts the inner surface of the second can 322.
[93]
The secondary battery 300 according to the third embodiment of the present invention has a difference in length between the center pin 330 and the electrode assembly 310 as compared to the secondary batteries according to the first and second embodiments described above. have. Accordingly, in the present embodiment, the overlapping contents of the first and second embodiments will be briefly described, and the differences will be mainly described.
[94]
[95]
13 is a perspective view showing an electrode assembly in a secondary battery according to a third embodiment of the present invention.
[96]
12 and 13, in the secondary battery 300 according to the third embodiment of the present invention, the center pin 330 is located at the center of the winding of the electrode assembly 310, and the reference when the electrode assembly 310 is wound. An axis or reference plane can be provided. Here, the electrode assembly 310 may surround the center pin 330 and may be wound around the center pin 330. At this time, the anode 312, the separator 314, and the cathode 311 are wound around the outer circumferential surface of the center pin 330, and the electrode assembly 310 perpendicular to the winding central axis C of the electrode assembly 310 It is possible to form a plurality of layers, respectively, in the thickness direction of.
[97]
In addition, the center pin 330 may be formed of an insulating material.
[98]
In addition, the center pin 330 may be provided in a cylindrical shape in which the center side is empty with respect to the central axis.
[99]
In addition, the length of the center pin 330 is formed equal to the length from one end of the cathode uncoated portion 311c to the other end of the anode uncoated portion 312c in the direction of the central axis C of winding of the electrode assembly 310 Can be. In this case, the length of the separator 314 in the direction of the winding central axis C of the electrode assembly 310 may be shorter than the length of the center pin 330.
[100]
In addition, one side of the center pin 330 may be in surface contact with the inner surface of the first can 321, and the other side of the center pin 330 may be in surface contact with the inner surface of the second can 322.
[101]
[102]
Hereinafter, a secondary battery according to a fourth embodiment will be described.
[103]
14 is a cross-sectional view showing a secondary battery according to a fourth embodiment of the present invention, and FIG. 15 is a perspective view showing an electrode assembly in the secondary battery according to the fourth embodiment of the present invention.
[104]
14 and 15, the secondary battery 400 according to the fourth embodiment of the present invention includes an electrode assembly 410 in which a positive electrode 412, a separator 414, and a negative electrode 411 are alternately stacked, It includes a can 420 that accommodates the electrode assembly 410 including the first can 421 and the second can 422 and a center pin 430 positioned at the center of the winding of the electrode assembly 410, and the cathode The uncoated portion 411c contacts the first can 421, and the anode uncoated portion 412c contacts the inner surface of the second can 422.
[105]
The secondary battery 400 according to the fourth embodiment of the present invention has a difference in length between the center pin 430 and the electrode assembly 410 as compared with the secondary batteries according to the first to third embodiments described above. have. Accordingly, in the present embodiment, content overlapping with the above-described embodiments will be briefly described, and the differences will be mainly described.
[106]
In the secondary battery 400 according to the fourth embodiment of the present invention, the center pin 430 may be positioned at the center of the winding of the electrode assembly 410 to provide a reference axis or a reference plane when the electrode assembly 410 is wound. Here, the electrode assembly 410 may surround the center pin 430 and may be wound around the center pin 430. At this time, the anode 412, the separator 414, and the cathode 411 are wound around the outer circumferential surface of the center pin 430, and the electrode assembly 410 perpendicular to the winding central axis C of the electrode assembly 410 It is possible to form a plurality of layers, respectively, in the thickness direction of.
[107]
In addition, the center pin 430 may be formed of an insulating material.
[108]
In addition, the center pin 430 may be provided in a cylindrical shape in which the center side is empty with respect to the central axis.
[109]
In addition, the length of the center pin 430 is to be formed shorter than the length from one end of the cathode uncoated portion 411c to the other end of the anode uncoated portion 412c in the direction of the winding central axis (C) of the electrode assembly 410. I can. Here, the cathode uncoated portion 411c is formed to extend longer in the direction of one side (C1) than the center pin 430 based on the winding central axis (C), and the anode uncoated portion 412c extends along the winding central axis (C) As a reference, it may be formed to extend longer in the direction of the other side (C2) than the center pin 430.
[110]
At this time, the length of the separator 414 in the direction of the winding central axis (C) of the electrode assembly 410 is formed longer than the length of the center pin 430, and at one end of the anode uncoated portion 411c, the anode uncoated portion ( It may be formed shorter than the length to the other end of 412c).
[111]
Meanwhile, one side of the center pin 430 may be positioned to be spaced apart from the inner surface of the first can 421, and the other side of the center pin 430 may be positioned to be spaced apart from the inner surface of the second can 422.
[112]
The length of the center pin 430 in the secondary battery 400 according to the fourth embodiment of the present invention configured as described above is one side of the negative electrode uncoated portion 411c in the direction of the winding central axis C of the electrode assembly 410 The length from the end to the other end of the anode uncoated part 412c is formed shorter than the separation membrane, and both sides of the center pin 430 are positioned to be spaced apart more from the first can 421 and the second can 422, The electrolyte collection space and the gas collection space can be increased.
[113]
[114]
Hereinafter, a secondary battery according to a fifth embodiment will be described.
[115]
16 is a cross-sectional view showing a secondary battery according to a fifth embodiment of the present invention, and FIG. 17 is a perspective view showing an electrode assembly in the secondary battery according to the fifth embodiment of the present invention.
[116]
16 and 17, the secondary battery 500 according to the fifth embodiment of the present invention includes an electrode assembly 510 in which a positive electrode 512, a separator 514, and a negative electrode 511 are alternately stacked, A can 520 containing the electrode assembly 510 including the first can 521 and the second can 522, and a center pin 530 positioned at the center of the winding of the electrode assembly 510, and a cathode The uncoated portion 511c contacts the first can 521, and the anode uncoated portion 512c contacts the inner surface of the second can 522.
[117]
The secondary battery 500 according to the fifth embodiment of the present invention has a difference in length of the center pin 530 and the electrode assembly 510 as compared to the secondary batteries according to the first to fourth embodiments described above. have. Accordingly, in the present embodiment, content overlapping with the above-described embodiments will be briefly described, and the differences will be mainly described.
[118]
In the secondary battery 500 according to the fifth embodiment of the present invention, the center pin 530 may be positioned at the center of the winding of the electrode assembly 510 to provide a reference axis or a reference plane when the electrode assembly 510 is wound. . Here, the electrode assembly 510 may surround the center pin 530 and may be wound around the center pin 530. At this time, the anode 512, the separator 514, and the cathode 511 are wound around the outer circumferential surface of the center pin 530, and the electrode assembly 510 perpendicular to the winding central axis C of the electrode assembly 510 It is possible to form a plurality of layers, respectively, in the thickness direction of.
[119]
In addition, the center pin 530 may be formed of an insulating material.
[120]
In addition, the center pin 530 may be provided in a cylindrical shape in which the center side is empty with respect to the central axis.
[121]
And, the length of the center pin 530 is to be formed longer than the length from one end of the negative uncoated portion 511c to the other end of the positive uncoated portion 512c in the direction of the central axis C of winding of the electrode assembly 510. I can. At this time, the length of the separator 514 in the direction of the winding central axis (C) of the electrode assembly 510 is to be formed shorter than the length from one end of the negative uncoated portion 511c to the other end of the positive uncoated portion 512c. I can.
[122]
In addition, one side of the center pin 530 may be in surface contact with the inner surface of the first can 521, and the other side of the center pin 530 may be in surface contact with the inner surface of the second can 522.
[123]
[124]
Hereinafter, a secondary battery according to a sixth embodiment will be described.
[125]
18 is a cross-sectional view showing a secondary battery according to a sixth embodiment of the present invention.
[126]
Referring to FIG. 18, the secondary battery 600 according to the sixth embodiment of the present invention includes an electrode assembly 610 in which a positive electrode 612, a separator 614, and a negative electrode 611 are alternately stacked, and a first can. It includes a can 620 for accommodating the electrode assembly 610 including the 621 and the second can 622 and a center pin 630 positioned at the center of the winding of the electrode assembly 610, and a negative electrode uncoated portion ( 611c contacts the first can 621, and the anode uncoated portion 612c contacts the inner surface of the second can 622.
[127]
The secondary battery 600 according to the sixth embodiment of the present invention differs in that the center pin 630 functions as a terminal as compared with the secondary batteries according to the first to fifth embodiments described above. Accordingly, in the present embodiment, content overlapping with the above-described embodiments will be briefly described, and the differences will be mainly described.
[128]
In the secondary battery 600 according to the sixth embodiment of the present invention, the center pin 630 may be positioned at the center of the winding of the electrode assembly 610 to provide a reference axis or a reference plane when the electrode assembly 610 is wound. Here, the electrode assembly 610 may surround the center pin 630 and be wound around the center pin 630. At this time, the anode 612, the separator 614, and the cathode 611 are wound around the outer circumferential surface of the center pin 630, and the electrode assembly 610 perpendicular to the winding central axis C of the electrode assembly 610 It is possible to form a plurality of layers, respectively, in the thickness direction of.
[129]
In addition, the center pin 630 may be formed of an insulating material.
[130]
In addition, the center pin 630 may be provided in a cylindrical shape in which the center side is empty with respect to the central axis.
[131]
And, the length of the center pin 630 is to be formed longer than the length from one end of the anode uncoated portion 611c to the other end of the anode uncoated portion 612c in the direction of the winding central axis (C) of the electrode assembly 610. I can. At this time, the length of the separator 614 in the direction of the winding central axis (C) of the electrode assembly 610 is to be formed shorter than the length from one end of the negative uncoated portion 611c to the other end of the positive uncoated portion 612c. I can.
[132]
Meanwhile, the center pin 630 may protrude outside the first can 621 and the second can 622. In this case, the center side of the first can 621 and the second can 622 may be fixed to the center pin 630.
[133]
Here, the center pin 630 is formed of an insulating material, and conductive materials 633 and 634 may be coated on one side and the other side of the center pin 630 in the direction of the winding central axis C of the electrode assembly 610. have.
[134]
At this time, one side of the first can 621 and the center pin 630 are electrically connected to one side of the center pin 630 to form the negative terminal 631, and the second can 622 and the center pin 630 The other side of the is electrically connected so that the other side of the center pin 630 may form the positive terminal 632.
[135]
In the secondary battery 600 according to the sixth embodiment of the present invention configured as described above, the center pin 630 protrudes to the outside of the first can 621 and the second can 622, and the center pin 630 As one side of the negative terminal 631 forms the negative terminal 631 and the other side forms the positive terminal 632, the center pin 630 may be used as an external terminal terminal when manufactured as a battery pack.
[136]
[137]
Although the present invention has been described in detail through specific examples, this is for explaining 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 idea of ​​the present invention.
[138]
In addition, the specific scope of protection of the invention will be made clear by the appended claims.
Claims
[Claim 1]
An electrode assembly in which an anode, a separator, and a cathode are alternately stacked; And a can accommodating the electrode assembly, wherein the negative electrode is located at an end portion in one direction so that a negative electrode uncoated portion, to which a negative electrode active material is not coated, protrudes more than the separator based on a winding central axis direction of the electrode assembly, The positive electrode is positioned at the other end of the positive electrode uncoated portion, to which the positive electrode active material is not coated, to protrude more than the separator based on the winding central axis direction of the electrode assembly, and the can includes a first can and a second can And the negative electrode uncoated portion directly contacts the inner surface of the first can, and the positive electrode uncoated portion directly contacts the inner surface of the second can.
[Claim 2]
The secondary battery according to claim 1, wherein the negative electrode uncoated portion is formed on the entire end of one side of the negative electrode along the winding direction, and the positive electrode uncoated portion is formed on the entire other end of the positive electrode along the winding direction.
[Claim 3]
The secondary battery according to claim 1, further comprising a center pin positioned at a center of the winding of the electrode assembly, wherein the electrode assembly is wound around the center pin.
[Claim 4]
The secondary battery according to claim 3, wherein the electrode assembly is wound while being fixed to the center pin with a tape.
[Claim 5]
The method according to claim 3, wherein the anode, the separator, and the cathode are wound around the outer circumferential surface of the center pin to form a plurality of layers, respectively, in the thickness direction of the electrode assembly perpendicular to the winding central axis of the electrode assembly. Secondary battery.
[Claim 6]
The secondary battery according to claim 3, wherein the center pin includes an insulating material.
[Claim 7]
The secondary battery according to claim 3, wherein the center pin is provided in a cylindrical shape.
[Claim 8]
The secondary battery according to claim 3, wherein a length of the center pin in the direction of a central axis of winding of the electrode assembly is shorter than a length of the other end of the anode uncoated portion at one end of the anode uncoated portion.
[Claim 9]
The secondary battery of claim 8, wherein a length of the separator in a direction of a central axis of winding of the electrode assembly is formed equal to a length of the center pin.
[Claim 10]
The secondary battery according to claim 8, wherein a length of the separator in a direction of a central axis of winding of the electrode assembly is longer than a length of the center pin, and is formed shorter than a length of the other end of the anode uncoated portion at one end of the anode uncoated portion.
[Claim 11]
The secondary battery according to claim 10, wherein one side of the center pin is positioned to be spaced apart from the inner surface of the first can, and the other side of the center pin is positioned to be spaced apart from the inner surface of the second can.
[Claim 12]
The secondary battery according to claim 3, wherein a length of the center pin in the direction of a central axis of winding of the electrode assembly is formed equal to a length of the other end of the anode uncoated portion from one end of the anode uncoated portion.
[Claim 13]
The secondary battery according to claim 9 and 12, wherein one side of the center pin makes surface contact with the inner surface of the first can, and the other side of the center pin makes surface contact with the inner surface of the second can.
[Claim 14]
The secondary battery according to claim 3, wherein a length of the center pin in the direction of a central axis of winding of the electrode assembly is longer than a length of the other end of the anode uncoated portion at one end of the anode uncoated portion.
[Claim 15]
The secondary battery of claim 14, wherein the center pin protrudes outward from the first can and the second can.
[Claim 16]
The method according to claim 15, wherein the center pin is formed of an insulating material, a conductive material is coated on one side and the other side of the center pin in the direction of the winding central axis of the electrode assembly, and the first can and the center pin A secondary battery in which one side of the center pin is electrically connected to form a positive terminal, and the second can and the other end of the center pin are electrically connected to form a negative terminal.
[Claim 17]
The secondary battery according to claim 15, wherein a center side of the first can and the second can is fixed to the center pin.