Title of the invention: Electric resistance welding device and battery manufacturing method using the same
Technical field
[One]
This application claims the benefit of priority based on Korean Patent Application No. 10-2018-0148841 filed on November 27, 2018, and all contents disclosed in the documents of the Korean patent application are included as part of this specification.
[2]
The present invention relates to an electric resistance welding apparatus and a battery manufacturing method using the same.
Background
[3]
Recently, interest in energy source prices and environmental pollution have increased due to depletion of fossil fuels, and the demand for eco-friendly alternative energy sources has become an indispensable factor for future life. Accordingly, research on various power generation technologies such as nuclear power, solar power, wind power, and tidal power is continuing, and a power storage device for more efficient use of the energy produced in this way is also receiving great interest.
[4]
Moreover, as technology development and demand for mobile devices and battery vehicles increase, the demand for batteries as an energy source is rapidly increasing, and accordingly, many studies on batteries that can meet various demands are being conducted. In particular, in terms of materials, there is a high demand for lithium secondary batteries such as lithium ion batteries and lithium ion polymer batteries having advantages such as high energy density, discharge voltage, and output stability.
[5]
Secondary batteries are classified according to the structure of an electrode assembly in which a positive electrode, a negative electrode, and a separator interposed between the positive electrode and the negative electrode are stacked. Typically, a jelly-roll type (wound type) electrode assembly in which a long sheet-shaped anode and cathode are wound with a separator interposed therebetween, a plurality of anodes and cathodes cut in units of a predetermined size with a separator interposed therebetween. Stacked (stacked) electrode assemblies that are sequentially stacked. Recently, in order to solve the problems of the jelly-roll type electrode assembly and the stack type electrode assembly, the jelly-roll type and the stack type are mixed. As an electrode assembly having an advanced structure, a stack/folding type electrode assembly having a structure in which unit cells in which a predetermined unit of anodes and cathodes are stacked with a separator interposed therebetween are sequentially wound on a separation film has been developed.
[6]
According to the purpose of use, such electrode assemblies are accommodated in a pouch case, a cylindrical can, and a square case to manufacture a battery.
[7]
Among them, cylindrical batteries are easy to manufacture and have high energy density per weight, so they are used as energy sources for various devices ranging from portable computers to battery vehicles.
[8]
1 is a schematic diagram showing welding of a negative electrode tab of a cylindrical battery to a metal can using a conventional electric resistance welding apparatus.
[9]
Referring to FIG. 1, the cylindrical battery 20 has a structure in which a jelly-roll type electrode assembly 24 is accommodated in a metal can 22. For convenience of description, only a portion of the electrode assembly 24 and the metal can 22 are illustrated. The battery resistance welding apparatus 10 has a structure in which the welding rod 12 is connected to the welding holder 11 and a current is applied to the welding rod 12 through the welding holder 11.
[10]
In order to weld the negative electrode tab 21 of the electrode assembly 24 to the metal can 22, the welding rod 12 of the electric resistance welding apparatus 10 passes between the separators 23 and one side of the welding rod 12 The end may contact the cathode tab 21. In this state, a current is applied to the welding rod to weld the negative electrode tab 21 to the metal can 22. At this time, a lot of thermal energy is generated in the welding rod 12 through which electric current flows, and this has a problem of lowering the welding strength between the cathode tab 21 and the metal can 22.
[11]
In addition, since the welding rod 12 is located in a narrow space between the separation membranes 23, there is a problem that the separation membrane 23 adheres to the welding rod 12 and melts during welding.
Detailed description of the invention
Technical challenge
[12]
An object of the present invention is to solve the problems of the prior art and technical problems that have been requested from the past.
[13]
After repeated in-depth research and various experiments, the inventors of the present application form an air outlet in the welding rod to discharge compressed air, as described later, to cool the thermal energy generated from the welding rod and remove the separator It confirmed that it can be separated, and came to complete the present invention.
Means of solving the task
[14]
The electric resistance welding apparatus according to the present invention for achieving this object includes a compressor, a welding holder, and a welding rod, and the air compressed by the compressor is introduced into the welding rod through the welding holder and formed on the welding rod. It can be discharged through air outlets.
[15]
The welding rod may include an air passage in the center.
[16]
The air passage may be in fluid communication with the air outlets.
[17]
The welding holder may include an air inlet and an air outlet.
[18]
Part of the air introduced through the air inlet may be introduced into the air flow path.
[19]
The remaining air not introduced into the air flow path may be discharged through the air discharge unit.
[20]
The air outlets may be formed at different frequencies depending on the length of the welding rod.
[21]
The air outlets may be formed in a slit shape.
[22]
The welding holder may include a valve that adjusts the amount of air introduced into the air flow path of the welding rod.
[23]
A method of manufacturing a battery using an electric resistance welding apparatus according to the present invention includes the steps of storing a jelly-roll type electrode assembly in a metal can; Injecting the welding rod into the center of the electrode assembly; Discharging the compressed air through the air outlet to push the separation membrane; And welding the negative electrode tab of the electrode assembly to the metal can by applying a current to the welding rod.
Brief description of the drawing
[24]
1 is a schematic diagram showing welding of a negative electrode tab of a cylindrical battery to a metal can using a conventional electric resistance welding apparatus.
[25]
2 is a schematic diagram of a battery resistance welding apparatus according to an embodiment of the present invention.
[26]
3 is a cross-sectional view taken along the dotted line A of FIG.
[27]
4 to 6 are schematic diagrams showing battery resistance welding devices according to another embodiment of the present invention.
[28]
7 and 8 are schematic diagrams showing a method of manufacturing a cylindrical battery using an electric resistance welding apparatus according to another embodiment of the present invention.
Mode for carrying out the invention
[29]
Hereinafter, various embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those of ordinary skill in the art may easily implement the present invention. The present invention may be implemented in various different forms and is not limited to the embodiments described herein.
[30]
In addition, throughout the specification, when a certain part "includes" a certain component, it means that other components may be further included rather than excluding other components unless otherwise stated.
[31]
In addition, throughout the specification, when referred to as "cross-sectional view", it means when the cross-section of the target portion is cut vertically viewed from the side.
[32]
2 is a schematic diagram of a battery resistance welding apparatus according to an embodiment of the present invention. 3 is a cross-sectional view taken along the dotted line A of FIG.
[33]
2 and 3, the battery resistance welding apparatus 100 may include a compressor 101, a welding holder 102, and a welding rod 103. Air compressed by the compressor 101 may be introduced into the welding rod 103 through the welding holder 102 and discharged through the air outlet 104.
[34]
The shape of the welding rod 103 is not particularly limited, but since the center of the jelly-roll type electrode assembly has a shape close to a circular shape, it may be formed in a cylindrical shape having a length compared to the diameter. One side of the welding rod 103 may be connected to the welding holder 102. An air passage 105 may be formed in the center C of the welding rod 103, and the air passage 105 may be in fluid communication with the welding holder 102.
[35]
A plurality of air outlets 104 may be formed on the side surface 109 of the welding rod 103, and the air outlets 104 may be in communication with the air flow path 105. The plurality of air outlets 104 may be formed along the side surface 109 to be formed in a radial direction from the center C of the welding rod 103.
[36]
The welding holder 102 may include an air inlet 106 and an air outlet 107. Air compressed by the compressor 101 is introduced into the welding holder 102 through the air inlet 106, and a part of the introduced air is introduced into the air flow path 105 of the welding rod 103. The remaining air that has not flowed into the air flow path 105 of the welding rod 103 may be discharged through the air discharge unit 107.
[37]
Through this structure, since the compressed air discharged from the air outlets 104 during welding can have a predetermined pressure, a separator (not shown) is welded so that the separator (not shown) does not adhere to the welding rod 103 It can be separated from the rod 103.
[38]
In addition, the air introduced into the air flow path 105 of the welding rod 103 may be discharged from the air outlets 104 to cool thermal energy generated from the welding rod 103 during welding.
[39]
4 is a schematic diagram showing an electric resistance welding apparatus according to another embodiment of the present invention.
[40]
Referring to FIG. 4, air outlets 104 in the welding rod 103 of the electric resistance welding apparatus 200 may be formed at different frequencies depending on the distance from the welding holder 102. The battery resistance welding apparatus 200 of FIG. 4 may include the same configurations as the battery resistance welding apparatus 100 of FIG. 2 except that the air outlets 104 are formed at different frequencies.
[41]
As described above, the welding rod 103 may be formed in a shape having a long length compared to the diameter. At this time, when the air outlets 104 are formed at the same frequency according to the length of the welding rod 103, the air discharged from the air outlets 104 formed close to the welding holder 102 and the welding holder 102 The amount of air discharged from the air outlets 104 formed at a distance may be different. Therefore, in the portion B where the welding rod 103 is in contact with the electrode tab (not shown), the amount of air discharged decreases to separate the separator (not shown) from the welding rod 103 and the welding rod 103 Cooling can be difficult. Accordingly, air outlets 104 are formed in the welding rod 103 of the electric resistance welding device 200 at different frequencies depending on the distance from the welding holder 102 so that a sufficient amount of air can be discharged from the part B. You can solve the problem. In the welding rod 103 of FIG. 4, more air outlets 104 than the air outlets 104 formed in a portion close to the welding holder 102 are formed in the B portion.
[42]
5 is a schematic diagram showing an electric resistance welding apparatus according to another embodiment of the present invention.
[43]
Referring to FIG. 5, the air outlet 104 formed in the welding rod 103 of the electric resistance welding apparatus 300 may be formed in various shapes. For example, the air outlet 104 may be formed in a slit shape. The slit-shaped air outlet 104 may be formed in the longitudinal direction of the welding rod 103. Through this structure, the amount of air discharged through the air outlet 104 at each position along the length of the welding rod 103 can be kept constant. The battery resistance welding apparatus 300 of FIG. 5 may include the same configurations as the battery resistance welding apparatus 100 of FIG. 2 except that the air outlet 104 is formed in a slit shape.
[44]
6 is a schematic diagram showing a battery resistance welding apparatus according to another embodiment of the present invention.
[45]
Referring to FIG. 6, the electric resistance welding apparatus 400 may include a valve 108 in the welding holder 102 to adjust the amount of air introduced into the air flow path 105 of the welding rod 103. The battery resistance welding apparatus 400 of FIG. 6 may include the same configurations as the battery resistance welding apparatus 100 of FIG. 2 except that the valve 108 is formed on the welding holder 102.
[46]
As another embodiment of the present invention, the valve 108 of FIG. 6 may also be applied to the embodiments of FIGS.
[47]
7 and 8 are schematic diagrams showing a method of manufacturing a cylindrical battery (hereinafter referred to as a “manufacturing method”) using the electric resistance welding apparatus according to the present invention.
[48]
2, 7 and 8, in the battery manufacturing method according to the present embodiment, the welding rod 103 of the electric resistance welding apparatus 100 is located in the center of the jelly-roll type electrode assembly 24, and welding It may include the step of contacting the end of the rod 103 to the negative electrode tab (21).
[49]
In this embodiment, compressed air by operating the compressor 101 is introduced into the air flow path 105 of the welding rod 103 through the welding holder 102, and the introduced air is discharged through the air outlet 104 It may include the step of. In FIG. 8, the air discharged through the air outlets 104 is indicated by an arrow. Air discharged through the air outlet 104 may separate the separation membrane 23 from the welding rod 103.
[50]
In this embodiment, it may include the step of welding the cathode tab 21 and the metal can 22 by applying a current to the welding rod 103. Air discharged through the air outlets 104 during welding may allow the separation membrane 23 to continue to be spaced apart from the welding rod 103. In addition, air discharged through the air outlets 104 during welding may cool the welding rod 103.
[51]
Those of ordinary skill in the field to which the present invention belongs will be able to make various applications and modifications within the scope of the present invention based on the above contents.
Industrial availability
[52]
As described above, the battery resistance welding apparatus according to an embodiment of the present invention can cool the heat energy generated from the welding rod during welding by forming an air outlet in the welding rod and prevent the separator from contacting the welding rod.
Claims
[Claim 1]
An electric resistance welding apparatus comprising a compressor, a welding holder, and a welding rod, wherein air compressed by the compressor is introduced into the welding rod through the welding holder and discharged through air outlets formed in the welding rod.
[Claim 2]
The electric resistance welding apparatus according to claim 1, wherein the welding rod includes an air flow path in a central portion.
[Claim 3]
The electric resistance welding apparatus according to claim 2, wherein the air flow path is in fluid communication with the air outlets.
[Claim 4]
The battery resistance welding apparatus according to claim 2, wherein the welding holder includes an air inlet and an air outlet.
[Claim 5]
The electric resistance welding apparatus according to claim 4, wherein a part of the air introduced through the air inlet is introduced into the air flow path.
[Claim 6]
The electric resistance welding apparatus according to claim 5, wherein the remaining air not introduced into the air passage is discharged through the air discharge unit.
[Claim 7]
The electric resistance welding apparatus according to claim 1, wherein the air outlets are formed at different frequencies depending on the length of the welding rod.
[Claim 8]
The electric resistance welding apparatus according to claim 1, wherein the air outlets are formed in a slit shape.
[Claim 9]
The electric resistance welding apparatus according to claim 1, wherein the welding holder comprises a valve that adjusts the amount of air introduced into the air flow path of the welding rod.
[Claim 10]
A method of manufacturing a battery using the electric resistance welding apparatus according to any one of claims 1 to 9, comprising: storing a jelly-roll type electrode assembly in a metal can; Injecting the welding rod into the center of the electrode assembly; Discharging the compressed air through the air outlet to push the separation membrane; And welding the negative electrode tab of the electrode assembly to the metal can by applying a current to the welding rod. Battery manufacturing method comprising a.