KR102666014B1 - Method of manufacturing cylindricality can for secondary battery and secondary battery comprising the same - Google Patents

Abstract

The present invention relates to a method of manufacturing a cylindrical can for a secondary battery and a secondary battery including the same. The technical problem to be solved is to maintain the rigidity of the case and reduce the resistance occurring in the current path through a case made of different metals.
For this purpose, the present invention includes a cylindrical can having a top opening, an electrode assembly accommodated in the cylindrical can, and a cap assembly that seals the top opening of the cylindrical can, and the cylindrical can has a circular plate shape and is disposed parallel to the cap assembly. It includes a first region portion and a second region portion bent from the outer periphery of the first region portion and extending in the direction of the cap assembly, wherein the first region portion and the second region portion are made of different metals, and the first region portion is formed in the second region. A secondary battery made of a metal with lower resistance compared to the secondary battery is disclosed.

Description

Method for manufacturing cylindrical cans for secondary batteries and secondary batteries including the same {METHOD OF MANUFACTURING CYLINDRICALITY CAN FOR SECONDARY BATTERY AND SECONDARY BATTERY COMPRISING THE SAME}

The present invention relates to a method of manufacturing a cylindrical can for a secondary battery and a secondary battery including the same.

A secondary battery is a power storage system that provides excellent energy density by converting electrical energy into chemical energy and storing it. Compared to primary batteries, which cannot be recharged, secondary batteries can be recharged and are widely used in IT devices such as smartphones, cellular phones, laptops, and tablet PCs. Recently, interest in electric vehicles has increased to prevent environmental pollution, and accordingly, high-capacity secondary batteries are being adopted for electric vehicles. These secondary batteries are required to have characteristics such as high density, high output, and stability.

The above-described information disclosed in the background technology of this invention is only for improving understanding of the background of the present invention, and therefore may include information that does not constitute prior art.

The present invention provides a method of manufacturing a cylindrical can for a secondary battery that can maintain the rigidity of the case and reduce the resistance occurring in the current path through a case made of different metals, and a secondary battery including the same.

A method of manufacturing a cylindrical can for a secondary battery according to the present invention and a secondary battery including the same include a cylindrical can having a top opening, an electrode assembly accommodated in the cylindrical can, and a cap assembly sealing the top opening of the cylindrical can, The cylindrical can includes a first region portion arranged parallel to the cap assembly in a circular plate shape, and a second region portion bent from an outer periphery of the first region portion and extending in the direction of the cap assembly, the first region portion The portion and the second region may be made of different metals, and the first region may be made of a metal with lower resistance than the second region.

The first area is the bottom surface of the cylindrical can, is made of copper, and can be electrically connected to the cathode of the electrode assembly.

The second area portion is a side wall of the cylindrical can and may be made of steel or a steel alloy.

The cylindrical can may have a joining area where the first area and the second area partially overlap and are pressed together.

The coupling area may be located on the bottom of the cylindrical can.

The coupling area may be located on a side wall of the cylindrical can.

A conductive adhesive may be interposed between the first region and the second region in the coupling region.

A welding area may be provided in the joining area where the first area and the second area overlap.

In addition, the method of manufacturing a cylindrical can for a secondary battery according to the present invention and the secondary battery including the same include the steps of preparing a second region in the shape of a circular ring plate with a circular opening in the center, and forming the circular opening on the upper surface of the second region. Preparing a circular plate consisting of the second region and the first region by seating the first region in the shape of a circular plate so as to cover it, and pressing the circular plate with a punch at the top of the first region, so that the upper portion is Forming an open cylindrical can, wherein the first region and the second region are made of different metals, and the first region may be made of a metal with lower resistance than the second region. there is.

In addition, the method of manufacturing a cylindrical can for a secondary battery according to the present invention and the secondary battery including the same include the steps of preparing a second region in the shape of a circular ring plate with a circular opening in the center, and punching at the upper part of the center of the second region. A first drawing processing step of pressurizing and processing into a cylindrical shape with the top and bottom open, and seating a first region in the shape of a circular plate on the top of the bottom surface of the second region to cover the circular opening, thereby forming the first region. Preparing a cylindrical member consisting of a second region portion and the first region portion, and pressing the upper portion of the first region portion of the cylindrical member with a punch to form a cylindrical can with an open top. The first area and the second area may be made of different metals, and the first area may be made of a metal with lower resistance than the second area.

In the circular plate or the cylindrical member, an outer area of the first area may overlap with the second area.

The method of manufacturing a cylindrical can for a secondary battery according to the present invention and the secondary battery including the same can maintain the rigidity of the case and reduce the resistance occurring in the current path through a case made of different metals.

1A, 1B, and 1C are a perspective view, an exploded perspective view, and a longitudinal cross-sectional view showing a secondary battery according to an embodiment of the present invention.
FIGS. 2A to 2D are examples sequentially showing the manufacturing process of the case shown in FIGS. 1A to 1C.
FIG. 3 is an enlarged cross-sectional view of three parts of FIG. 2D.
Figures 4A to 4F are another example sequentially showing the manufacturing process of the case shown in Figures 1A to 1C.
Figure 5 is an enlarged cross-sectional view of part 5 of Figure 4f.
Figure 6 is a longitudinal cross-sectional view showing a secondary battery according to another embodiment of the present invention.
FIGS. 7A and 7B are enlarged views of portions 7A and 7B of FIG. 7.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings.

The embodiments of the present invention are provided to more completely explain the present invention to those skilled in the art, and the following examples may be modified into various other forms, and the scope of the present invention is as follows. It is not limited to the examples. Rather, these embodiments are provided to make the disclosure more faithful and complete, and to fully convey the spirit of the invention to those skilled in the art.

In addition, in the drawings below, the thickness and size of each layer are exaggerated for convenience and clarity of explanation, and the same symbols refer to the same elements in the drawings. As used herein, the term “and/or” includes any one and all combinations of one or more of the listed items. In addition, the meaning of "connected" in this specification refers not only to the case where member A and member B are directly connected, but also to the case where member C is interposed between member A and member B to indirectly connect member A and member B. do.

The terms used herein are used to describe specific embodiments and are not intended to limit the invention. As used herein, the singular forms include the plural forms unless the context clearly indicates otherwise. Additionally, when used herein, “comprise” and/or “comprising” means specifying the presence of stated features, numbers, steps, operations, members, elements and/or groups thereof. and does not exclude the presence or addition of one or more other shapes, numbers, operations, members, elements and/or groups.

Although the terms first, second, etc. are used herein to describe various members, parts, regions, layers and/or parts, these members, parts, regions, layers and/or parts are limited by these terms. It is obvious that this cannot be done. These terms are used only to distinguish one member, component, region, layer or section from another region, layer or section. Accordingly, a first member, component, region, layer or portion described below may refer to a second member, component, region, layer or portion without departing from the teachings of the present invention.

Space-related terms such as “beneath,” “below,” “lower,” “above,” and “upper” are used to refer to an element or feature shown in a drawing. It is used for easy understanding of other elements or features. These space-related terms are for easy understanding of the present invention according to various process states or usage states of the present invention, and are not intended to limit the present invention. For example, if an element or feature in a drawing is flipped over, an element described as “bottom” or “below” becomes “top” or “above.” Therefore, “below” is a concept encompassing “top” or “below.”

FIG. 1A is a perspective view showing a secondary battery 100 according to various embodiments of the present invention, FIG. 1B is an exploded perspective view of the secondary battery 100 shown in FIG. 1A, and FIG. 1C. A longitudinal cross-sectional view of the secondary battery 100 shown in 1a is shown. Here, the longitudinal cross section is a cross section of the secondary battery 100 cut in the longitudinal direction.

As shown in FIGS. 1A, 1B, and 1C, the secondary battery 100 according to the present invention includes a cylindrical can 110, an electrode assembly 120 stored inside the cylindrical can 110, and a cylindrical can 110. ) includes a cap assembly 130 that seals the top opening.

The cylindrical can 110 includes a first region 111 in the shape of a circular plate, and a second region 112 bent from the outer periphery of the first region 111 and extending upward for a certain length. . The top of this cylindrical can 110 is opened during the manufacturing process of the secondary battery 100.

Here, the first area 111 may be located on the bottom of the cylindrical can 110, and the second area 112 may be located on a side wall extending vertically from the bottom of the cylindrical can 110. You can.

The first region 111 and the second region 112 of the cylindrical can 110 may be made of different metals. Preferably, the first region 111 of the cylindrical can 110 may be made of a metal with lower resistance than the second region 112. Additionally, the second region 112 of the cylindrical can 110 may be made of a metal with higher strength than the first region 111.

For example, the second area 112 may be made of steel or a steel alloy with high rigidity, and the first area 111 may be made of copper, which has lower resistance than steel or a steel alloy. The first area 111 of the cylindrical can 110 may be a negative terminal. That is, the first region 111 is a negative terminal that is directly connected to the external electronic device or charger when the secondary battery 110 is connected to the external electronic device or charger for discharging or charging.

The cylindrical can 110 has a second region 112 made of steel or a steel alloy to have rigidity, and a first region 111 to be electrically connected to the electrode assembly 120 is a second region 112. ), the resistance occurring in the current path can be reduced by making it made of a metal with lower resistance than that of the metal.

The cylindrical can 110 may be formed through drawing work to facilitate coupling between the first region 111 and the second region 112 made of different metals. Additionally, a conductive adhesive may be interposed between the first area 111 and the second area 112 for connection and fixation, or they may be joined by laser welding or ultrasonic welding. The manufacturing process of such a cylindrical can 110 will be described in detail below.

Referring to FIGS. 2A to 2D , an example sequentially showing the manufacturing process of the cylindrical can 110 shown in FIGS. 1A to 1C is shown.

First, as shown in FIG. 2A, a circular opening 112a is formed penetrating between the upper and lower surfaces of the center of the circular plate-shaped second region 112 to form a circular ring-shaped second region 112. prepare. The second area portion 112 may be a steel or steel alloy plate.

As shown in FIG. 2B, the first region 111 in the shape of a circular plate is seated on the upper surface of the second region 112 in the shape of a circular ring plate. At this time, the first area 111 may be seated on the upper surface of the second area 112 so as to cover the circular opening 112a of the second area 112 .

The first area 111 may have a larger planar size than the planar size of the circular opening 112a formed in the second area 112 . That is, the outer area of the first area 111 may overlap with the second area 112. The overlapping area of the first area 111 and the second area 112 may be bonded and fixed by laser welding, ultrasonic welding, or conductive adhesive. The first area 111 may be made of a different metal than the second area 112, and is preferably made of copper. Hereinafter, the second area 112 on which the first area 111 is seated and fixed will be referred to as a circular plate 115.

As shown in FIG. 2C, a circular plate 115 is placed on the upper part of the die 12 in which a circular hole (not shown) penetrating between the upper and lower surfaces is formed at the center. At this time, the punch 11 may be located on the upper part of the circular plate 115. That is, the circular plate 115 may be interposed between the die 12 and the punch 11.

In addition, the punch 11 presses the circular plate 115 from the top toward the center where the first region 111 is located, forming a cylindrical can 110 with an open top as shown in FIG. 2D. . That is, the cylindrical can 110 may be formed through drawing work. The cylindrical can 110 formed through this manufacturing process may have a side wall where the second region 112 is located and a bottom surface where the first region 111 is located made of different metals.

Additionally, referring to FIG. 3, an enlarged cross-sectional view of three parts of the cylindrical can 110 shown in FIG. 2D is shown. As shown in FIG. 3, the lower end of the second region 112 of the cylindrical can 110 is bent so as to partially cover the outer end of the first region 111, It may extend in the direction of the first area 111. Preferably, the cylindrical can 110 may be provided with a coupling region 110a on the bottom surface in which the outer end of the first region 111 partially overlaps and joins the lower end of the second region 112. That is, in the cylindrical can 110 manufactured by drawing the circular plate 115, the joining area 110a may be located on the bottom of the cylindrical can 110. Additionally, the joining area 110a may be provided with a conductive adhesive interposed between the first area 111 and the second area 112 or a welding area welded by laser welding or ultrasonic welding.

Referring to FIGS. 4A to 4F , another example sequentially showing the manufacturing process of the cylindrical can 110 shown in FIGS. 1A to 1C is shown.

First, as shown in FIG. 4A, a circular opening 112a is formed penetrating between the upper and lower surfaces of the center of the circular plate-shaped second region 112 to form a circular ring-shaped second region 112. prepare. The second area portion 112 may be a steel or steel alloy plate.

As shown in FIG. 4B, the second area portion 112 in the shape of a circular plate is placed on the upper part of the die 12 in which a circular hole (not shown) penetrating between the upper and lower surfaces is formed at the center. At this time, the punch 11 may be located at the top of the second area 112. That is, the second area portion 112 may be interposed between the die 12 and the punch 11.

In addition, the punch 11 presses from the top of the second area 112 toward the center where the circular opening 112a is located, forming a cylindrical second area 112 with the top and bottom open as shown in FIG. 4C. ) to form. That is, the second region 112 may be formed into a cylindrical shape with the top and bottom open through primary drawing processing. Additionally, the second area portion 112 may include an extension portion 112b whose lower end is bent inward through drawing processing. Accordingly, the size of the upper opening of the second area 112 may be larger than the size of the lower opening. Additionally, the lower opening of the second area 112 is formed by a circular opening 112a.

As shown in FIG. 4D, the first region 111 in the shape of a circular plate is seated on the top of the bottom surface of the second region 112. At this time, the first area 111 may be seated on the upper part of the bottom surface of the second area 112 so as to cover the circular opening 112a of the second area 112 . Additionally, in the second area 112, the first area 111 may be seated on the upper part of the extension part 112b. The first area 111 may have a larger planar size than the planar size of the circular opening 112a formed in the second area 112 . That is, the outer area of the first area 111 may overlap the extension 112b of the second area 112. The overlapping area of the first area 111 and the second area 112 may be bonded and fixed by laser welding, ultrasonic welding, or conductive adhesive. The first area 111 may be made of a different metal than the second area 112, and is preferably made of copper. Hereinafter, the second area 112 on which the first area 111 is seated and fixed will be referred to as a cylindrical member 116.

As shown in FIG. 4E, a cylindrical member 116 is placed on the upper part of the die 14 with a circular hole penetrating between the upper and lower surfaces at the center. At this time, the punch 13 may be located on the top of the cylindrical member 116. That is, the cylindrical member 116 may be interposed between the die 14 and the punch 13.

In addition, the punch 13 presses from the top of the cylindrical member 116 toward the center where the first region 111 is located, forming a cylindrical can 110 with an open top as shown in FIG. 4F. . That is, the cylindrical can 110 forms a cylindrical second region 112 with open top and bottom through a primary drawing process, and a first region portion ( 111) can be formed through a secondary drawing process. The cylindrical can 110 formed through this manufacturing process may have a side wall where the second region 112 is located and a bottom surface where the first region 111 is located made of different metals.

Additionally, referring to FIG. 5, an enlarged cross-sectional view of five portions of the cylindrical can 110 shown in FIG. 4F is shown. As shown in FIG. 5 , the cylindrical can 110 may be partially extended by bending the outer periphery of the first area 111 upward. That is, the outer end of the first area 111 may be bent and extended upward and overlap the lower end of the second area 112. At this time, the lower end of the second area 112 may partially cover the outer end of the first area 111. Preferably, the cylindrical can 110 may be provided with a coupling region 110a on the side wall where the outer end of the first region 111 partially overlaps and is coupled to the lower end of the second region 112. That is, in the cylindrical can 110 manufactured by drawing the cylindrical member 116, the joining area 110a may be located on the side wall of the cylindrical can 110. Additionally, the joining area 110a may be provided with a conductive adhesive interposed between the first area 111 and the second area 112 or a welding area welded by laser welding or ultrasonic welding.

The top of the cylindrical can 110 is opened during the manufacturing process of the secondary battery 100. Therefore, during the assembly process of the secondary battery, the electrode assembly 120 may be inserted into the interior of the cylindrical can 110 through the top opening along with the electrolyte solution. The cylindrical can 110 with the electrode assembly 120 inserted therein has a beading part (113) recessed in the lower portion centered on the cap assembly 130 to prevent the electrode assembly 120 from being released to the outside. ) is formed, and an inwardly bent crimping part 114 may be formed on its upper part.

The electrode assembly 120 is accommodated inside the cylindrical can 110 together with the electrolyte solution. Here, the electrolyte is an organic liquid containing a salt that is injected to allow lithium ions to move between the positive and negative electrode plates constituting the electrode assembly 120, and includes lithium salts such as LiPF6, LiBF4, and LiClO4 and a high-purity organic solvent. It may include a non-aqueous organic electrolyte solution that is a mixture of the following, but this is not limited to the present invention.

The electrode assembly 120 includes a negative electrode plate 121 coated with a negative electrode active material, a positive electrode plate 122 coated with a positive electrode active material, and the negative electrode plate 121 and the positive electrode plate 122 interposed between the negative electrode plate 121 and the positive electrode plate 122. ) and includes a separator 123 that prevents short circuits and only allows movement of lithium ions. After the electrode assembly 120 is stacked with the negative electrode plate 121, the positive plate 122, and the separator 123, the electrode assembly 120 is wound from the tip of the electrode assembly and wound into a substantially cylindrical shape. Here, the negative plate 121 may be copper (Cu) or nickel (Ni) foil, the positive plate 122 may be aluminum (Al) foil, and the separator 123 may be polyethylene (PE) or polypropylene (PP), but the present invention does not limit the above materials. In addition, a negative electrode tab 124 that protrudes and extends a certain length downward may be attached to the negative electrode plate 121, and a positive electrode tab 125 that protrudes upward a certain length may be attached to the positive electrode plate 122. In addition, the negative electrode tab 124 may be made of copper or nickel, and the positive electrode tab 125 may be made of aluminum, but the above materials are not limited to the present invention. Additionally, the electrode assembly 120 may be a high output cell,

In addition, the first insulating plate 126, which is coupled to the cylindrical can 110 and has a first hole 126a in the center and a second hole 126b outside it, is connected to the electrode assembly 120 and the cylindrical can 110. It may be interposed between the first area portions 111. This first insulating plate 126 serves to prevent the electrode assembly 120 from electrically contacting the first area 111, which is the bottom of the cylindrical can 110. In particular, the first insulating plate 126 serves to prevent the positive plate 122 of the electrode assembly 120 from electrically contacting the first area 111, which is the bottom of the cylindrical can 110. Here, the first hole 126a serves to allow the gas to quickly move upward through the center of the electrode assembly 120 when a large amount of gas is generated due to an abnormality in the secondary battery, and the second hole 126b It serves to allow the silver cathode tab 124 to penetrate and be welded to the first region 111 made of copper.

In addition, the second insulating plate 127 is coupled to the cylindrical can 110 and has a first hole 127a in the center and a plurality of second holes 127b outside the electrode assembly 120 and the cap assembly 130. ) may be interposed between. This second insulating plate 127 serves to prevent the electrode assembly 120 from electrically contacting the cap assembly 130. In particular, the second insulating plate 127 serves to prevent the negative electrode plate 121 of the electrode assembly 120 from electrically contacting the cap assembly 130. Here, the first hole (127a) serves to quickly move the gas to the cap assembly 130 when a large amount of gas is generated due to an abnormality in the secondary battery, and the second hole (127b) serves to allow the gas to quickly move to the cap assembly 130. ) serves to penetrate through and be welded to the cap assembly 130. Additionally, the remaining second hole 127b serves to allow the electrolyte to quickly flow into the electrode assembly 120 during the electrolyte injection process.

The cap assembly 130 includes a cap-up 131 having a plurality of through holes 131d, a safety plate 133 installed on the lower part of the cap-up 131, and a lower portion of the safety plate 133. An installed connecting ring 135, a cap-down 136 coupled to the connecting ring 135 and having first and second through holes 136a, 136b, and fixed to the lower part of the cap-down 136 to form an anode. The sub plate 137 welded and electrically connected to the tab 125, the cap up 131, the safety plate 133, the connecting ring 135, and the cap down 136 are placed in the second part of the cylindrical can 110. It includes an insulating gasket 138 that insulates from the area 112. This configuration of the cap assembly 130 is an example, and the configuration of the cap assembly 130 is not limited to this configuration.

Here, the sub plate 137 may be electrically connected to the cap up 131 through the safety plate 133. Additionally, the cap up 131 is a positive terminal that is directly connected to the external electronic device or charger when the secondary battery 110 is connected to the external electronic device or charger for discharging or charging.

Here, the insulating gasket 138 is substantially pressed between the beading portion 113 and the crimping portion 114 formed in the second region 112 of the cylindrical can 110. In addition, the through hole 131d formed in the cap up 131 and the through hole 136b formed in the cap down 136 are used to discharge internal gas to the outside when abnormal internal pressure occurs inside the cylindrical can 110. It plays a role. Of course, due to this internal pressure, the safety plate 133 is first flipped upward and electrically separated from the sub-plate 137, and then the safety plate 133 is torn and the gas inside is released to the outside.

The secondary battery 100 including the cylindrical can 110 made of such a different metal can improve durability because the second region 112 is made of steel or a steel alloy, and the negative electrode tab of the electrode assembly 120 ( By making the first area 111 electrically connected to 124 made of copper, resistance occurring in the current path can be reduced.

Referring to FIG. 6, it is a cross-sectional view showing a secondary battery 200 according to another embodiment of the present invention.

As shown in FIG. 6, the secondary battery 200 according to another embodiment of the present invention includes a cylindrical can 110, an electrode assembly 220 stored inside the cylindrical can 110, and an upper end of the cylindrical can 110. It includes a cap assembly 130 that seals the opening. The configuration of the cylindrical can 110 and cap assembly 130 of the secondary battery 200 is the same as that of the secondary battery 100 shown in FIG. 1 . Therefore, the description will focus on the configuration of the electrode assembly 220 in the secondary battery 200, which is different from the secondary battery 100.

The electrode assembly 220 is accommodated inside the cylindrical can 110 together with the electrolyte solution. Here, the electrolyte is an organic liquid containing a salt that is injected to allow lithium ions to move between the positive and negative electrode plates constituting the electrode assembly 220, and includes lithium salts such as LiPF6, LiBF4, and LiClO4 and a high-purity organic solvent. It may include a non-aqueous organic electrolyte solution that is a mixture of the following, but this is not limited to the present invention.

The electrode assembly 220 includes a negative electrode plate 221 coated with a negative electrode active material, a positive electrode plate 222 coated with a positive electrode active material, and is interposed between the negative electrode plate 221 and the positive electrode plate 222 to form the negative electrode plate 221 and the positive electrode plate 222. ) and includes a separator 223 that prevents short circuits and only allows movement of lithium ions. After the negative electrode plate 221, the positive plate 222, and the separator 223 are stacked, the electrode assembly 220 is wound from the tip of the electrode assembly and wound into a substantially cylindrical shape.

First, the negative electrode plate 221 of the electrode assembly 220 is a negative electrode current collector plate 221a, which is a plate-shaped metal foil made of copper (Cu) or nickel (Ni). A negative electrode coating layer 221b, which is a silicon-based negative electrode active material, is coated on both sides. . The negative electrode current collector plate 221a is further provided with a negative electrode uncoated region 221c on both sides of the lower end in the longitudinal direction of the electrode assembly 220, where the negative electrode coating layer 221b is not formed. Additionally, the negative electrode uncoated region 221c may protrude further toward the bottom of the electrode assembly 220 than the positive electrode plate 222 and the separator 223. That is, the electrode assembly 220 may have a negative electrode uncoated region 221c located on the lower surface. Additionally, compared to the positive electrode plate 222, the separator 223 of the electrode assembly 220 extends and protrudes further downward in the longitudinal direction, thereby maintaining electrical insulation between the negative electrode plate 221 and the positive plate 222. Additionally, the separator 223 may serve to prevent the positive plate 222 of the electrode assembly 220 from electrically contacting the negative current collection tab 224.

Additionally, the negative electrode current collection tab 224 may be welded to the negative electrode uncoated region 221c located on the lower surface of the electrode assembly 220. The negative electrode current collection tab 224 has a substantially circular plate shape and can be electrically connected to the electrode assembly 220 by laser welding while in close contact with the lower surface of the electrode assembly 220. That is, the negative electrode current collection tab 224 may be respectively welded to a plurality of negative electrode uncoated portions 221c protruding from the lower surface of the electrode assembly 220 to serve as a negative electrode current collector. The planar size of the negative electrode current collection tab 224 may be smaller than the size of the bottom surface of the electrode assembly 220. Additionally, the negative electrode current collection tab 224 may have the same central axis as the lower surface of the electrode assembly 220. This negative electrode current collection tab 224 can electrically connect the electrode assembly 220 to the first area 111 on the bottom of the cylindrical can 110, and is in contact with the second area 112. can be prevented.

The negative electrode current collection tab 224 is each welded to a plurality of negative electrode uncoated portions 221c, thereby facilitating the flow of current, thereby reducing resistance due to current concentration in the high-capacity and high-output secondary battery 200. The negative electrode current collection tab 224 may be made of copper or nickel, but this is not limited to the present invention. Additionally, the negative electrode current collection tab 224 may be interposed between the lower surface of the electrode assembly 220 and the first area 111 of the cylindrical can 110. Additionally, the negative electrode current collection tab 224 may be resistance welded to the first region 111 of the cylindrical can 110, but the welding method is not limited to the present invention. Additionally, the first area 111 of the cylindrical can 110 may operate as a cathode.

The positive electrode plate 222 has a positive electrode current collector plate 222a, which is a plate-shaped metal foil made of aluminum (Al), coated with a positive electrode coating layer 222b, which is an active material made of a transition metal oxide, on both sides. In addition, the positive electrode current collector plate 222a is further provided with a positive electrode uncoated region 222c on both sides of the longitudinal upper portion of the electrode assembly 220, where the positive electrode coating layer 222b is not formed. Additionally, the anode uncoated region 222c may protrude further toward the top of the electrode assembly 220 than the cathode plate 221 and the separator 223. That is, the electrode assembly 220 may have an anode uncoated region 222c located on its upper surface. Additionally, in the electrode assembly 220, the separator 223 extends and protrudes further upward in the longitudinal direction compared to the negative electrode plate 221, thereby maintaining electrical insulation between the negative electrode plate 221 and the positive plate 222.

Additionally, the positive electrode current collection tab 225 may be welded to the positive electrode uncoated region 222c located on the upper surface of the electrode assembly 220. The positive electrode current collection tab 225 has a substantially circular plate shape and can be electrically connected to the electrode assembly 220 by laser welding while in close contact with the upper surface of the electrode assembly 220. That is, the positive electrode current collection tab 225 may be respectively welded to a plurality of positive electrode uncoated portions 222c protruding from the upper surface of the electrode assembly 220 to function as a positive electrode current collector. The planar size of the positive electrode current collection tab 225 may be smaller than the top surface size of the electrode assembly 220. Additionally, the positive electrode current collection tab 225 may have the same central axis as the upper surface of the electrode assembly 220. This positive electrode current collection tab 225 can prevent electrical connection by contacting the inner surface of the cylindrical can 110.

Such positive electrode current collection tabs 225 are each welded to a plurality of positive electrode uncoated portions 222c to facilitate the flow of current, thereby reducing resistance due to current concentration in the high-capacity and high-output secondary battery 200. The positive electrode current collection tab 225 may be made of aluminum, but this is not limited to the present invention. Additionally, the positive electrode current collection tab 225 may be interposed between the upper surface of the electrode assembly 220 and the cap assembly 130. Additionally, the positive current collection tab 225 may be electrically connected to the cap assembly 130 through the positive lead tab 226. At this time, the cap assembly 130 may operate as an anode.

What has been described above is only an example of the method for manufacturing a cylindrical can for a secondary battery according to the present invention and a secondary battery including the same, and the present invention is not limited to the above-described embodiment, but is scoped in the following patent claims. As claimed, it will be said that the technical spirit of the present invention extends to the extent that anyone skilled in the art can make various changes without departing from the gist of the present invention.

100, 200: secondary battery 110; cylindrical can
111; Area 1 112; Area 2
120, 220; electrode assembly 130; cap assembly

Claims (12)

A cylindrical can with a top opening;
an electrode assembly accommodated in the cylindrical can and having a positive electrode tab protruding upward and a negative electrode tab protruding downward; and
Comprising a cap assembly that seals the top opening of the cylindrical can,
The cylindrical can has a circular plate shape and is disposed parallel to the cap assembly, a first region welded to the negative electrode tab, and a second region bent from the outer periphery of the first region and extending in the direction of the cap assembly. includes wealth,
A secondary battery, wherein the first region and the second region are made of different metals, and the first region is made of a metal with lower resistance than the second region. In claim 1,
The first region is a bottom surface of the cylindrical can, is made of copper, and is electrically connected to the cathode of the electrode assembly. In claim 1,
The second region is a side wall of the cylindrical can, and is made of steel or a steel alloy. In claim 1,
The cylindrical can is a secondary battery characterized in that the first region portion and the second region portion partially overlap and have a coupling region in which the first region portion and the second region portion are combined by pressure. In claim 4,
The secondary battery is characterized in that the bonding area is located on the bottom of the cylindrical can. In claim 4,
The secondary battery is characterized in that the coupling area is located on the side wall of the cylindrical can. In claim 4,
A secondary battery, characterized in that a conductive adhesive is interposed between the first region and the second region in the coupling region. In claim 4,
A secondary battery, characterized in that a welding area is provided in the joining area where the first area part and the second area part overlap. Preparing a second region in the shape of a circular ring plate with a circular opening in the center;
preparing a circular plate consisting of the second region and the first region by seating a circular plate-shaped first region on the upper surface of the second region to cover the circular opening; and
Forming a cylindrical can with an open top by pressing the circular plate at the top of the first area with a punch,
A method of manufacturing a cylindrical can for a secondary battery, wherein the first region and the second region are made of different metals, and the first region is made of a metal with lower resistance than the second region. Preparing a second region in the shape of a circular ring plate with a circular opening in the center;
A first drawing process step of pressing the upper part of the center of the second area with a punch and processing it into a cylindrical shape with open upper and lower parts;
preparing a cylindrical member composed of the second region and the first region by seating a circular plate-shaped first region on an upper part of the bottom surface of the second region to cover the circular opening; and
A secondary drawing process step of forming a cylindrical can with an open top by pressing the upper portion of the first region of the cylindrical member with a punch,
A method of manufacturing a cylindrical can for a secondary battery, wherein the first region and the second region are made of different metals, and the first region is made of a metal with lower resistance than the second region. In claim 9,
In the circular plate
A method of manufacturing a cylindrical can, wherein an outer area of the first area overlaps with the second area. In claim 10,
In the cylindrical member
A method of manufacturing a cylindrical can, wherein an outer area of the first area overlaps with the second area.

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