Electrode surface treatment apparatus and electrode coating system including the same

Abstract

An electrode surface treatment apparatus according to an embodiment of the present invention includes a guide roll configured to support an electrode foil by contacting the electrode foil that moves in the machine direction and guide the movement of the electrode foil, and a plasma unit configured to perform surface treatment on the electrode foil by injecting plasma onto the electrode foil while the electrode foil is moving.

Description

Technical Field

[0001] This application claims priority based on Korean Patent Application No. 10-2022-0178976 filed on December 20, 2022, and Korean Patent Application No. 10-2023-0028739 filed on March 3, 2023, and all of the content disclosed in the specifications and drawings of the said applications is incorporated into this application.

[0002] The present invention relates to an electrode surface treatment apparatus and an electrode coating system including the same, and more particularly, to an electrode surface treatment apparatus for performing surface treatment on an electrode foil to which a coating material containing an electrode active material is applied, and an electrode coating system including the same.

Background Art

[0003] Generally, a secondary battery refers to a battery that can be repeatedly charged and discharged, such as a lithium-ion battery, a lithium polymer battery, a nickel cadmium battery, a nickel metal hydride battery, a nickel zinc battery, etc. Such a secondary battery can be manufactured by a method of accommodating an electrode assembly including a positive electrode and a negative electrode laminated with each other with a separator interposed therebetween and an electrolyte material in cases of various shapes and sealing the cases.

[0004] Electrodes such as the positive electrode and the negative electrode of such a secondary battery can be roughly classified into wet electrodes and dry electrodes according to their manufacturing methods. A wet electrode is manufactured through a process of applying a slurry-like electrode mixture containing a solvent to the surface of an electrode foil corresponding to a current collector to form a coating layer and drying the coating layer. On the other hand, a dry electrode is manufactured through a process of pressing a solid-phase electrode mixture not containing a solvent onto the surface of an electrode foil to form a coating layer.

[0005] Recently, due to problems such as harmful gases being generated by the solvent contained in the electrode binder of the wet electrode during the drying process, and wrinkles, pinholes, cracks, etc. occurring in the coating layer of the wet electrode after the solvent is dried, research and development efforts have been actively carried out on manufacturing technologies for dry electrodes that can replace wet electrodes.

[0006] However, there is a problem that it is difficult to adhere the electrode binder because foreign substances such as rolling oil exist on the surface of the electrode foil corresponding to the current collector of the electrode. Such problems are more serious in dry electrodes to which a solid-state electrode binder adheres than in wet electrodes to which a slurry-state electrode binder adheres.

[0007] In addition, existing technologies have a problem that it takes a great deal of time and cost to manufacture the electrode foil because, in order to increase the adhesion of the electrode foil, after washing the electrode foil, the surface of the electrode foil is entirely or partially coated with a primer containing a conductive substance and a binder.

Summary of the Invention

Problems to be Solved by the Invention

[0008] The technical problem to be solved by the present invention is to provide an electrode surface treatment apparatus and an electrode coating system including the same that can enhance the adhesion between the electrode foil and the electrode binder and improve the quality of the electrode.

[0009] Another technical problem to be solved by the present invention is to provide an electrode surface treatment apparatus and an electrode coating system including the same that can shorten the manufacturing time of the electrode and reduce the manufacturing cost while increasing the capacitance and energy density of the electrode.

Means for Solving the Problems

[0010] An electrode surface treatment apparatus according to one aspect of the present invention includes a guide roll configured to support an electrode foil in contact therewith and guide the movement of the electrode foil as the electrode foil moves in the longitudinal direction (Machine Direction), and a plasma unit configured to perform surface treatment on the electrode foil by injecting plasma onto the electrode foil while the electrode foil is moving.

[0011] In one embodiment, the plasma unit may be configured to inject plasma onto a portion of the electrode foil that is in contact with and supported by the guide roll.

[0012] In one embodiment, the electrode surface treatment apparatus may include a plurality of the plasma units, and the plurality of plasma units may be arranged in the transverse direction and each configured to inject plasma onto the electrode foil.

[0013] In one embodiment, the electrode surface treatment apparatus may include a plurality of the guide rolls, and the plurality of guide rolls may include a first guide roll that contacts and supports the electrode foil on the bottom surface of the electrode foil and a second guide roll that contacts and supports the electrode foil on the upper surface of the electrode foil.

[0014] In one embodiment, the electrode surface treatment apparatus may include a plurality of the plasma units, and the plurality of plasma units may include at least one first plasma unit configured to inject plasma onto a first portion of the electrode foil that is in contact with and supported by the first guide roll and at least one second plasma unit configured to inject plasma onto a second portion of the electrode foil that is in contact with and supported by the second guide roll.

[0015] In one embodiment, the guide roll may have a hollow interior, and the plasma unit may be disposed in the hollow of the guide roll.

[0016] In one embodiment, the guide roll includes a through hole provided on an outer surface of the guide roll and communicating with the hollow, and the plasma unit may be configured to inject plasma onto a surface of the electrode foil through the through hole.

[0017] In one embodiment, the through hole may have a constant width and may have a shape of a long hole or a slit extending in a transverse direction.

[0018] In one embodiment, an extending length of the through hole extending in the transverse direction may be configured to be shorter than a width of the electrode foil.

[0019] In one embodiment, the electrode surface treatment apparatus includes a plurality of the guide rolls and a plurality of the plasma units, and at least one first plasma unit among the plurality of plasma units is disposed in a hollow of a first guide roll among the plurality of guide rolls, and at least one second plasma unit among the plurality of plasma units may be disposed in a hollow of a second guide roll among the plurality of guide rolls.

[0020] In one embodiment, the electrode surface treatment apparatus further includes an unwinder configured to unwind the electrode foil wound in a roll shape and move it in the longitudinal direction, and the guide roll may be configured to guide the electrode foil moved by the unwinder.

[0021] In one embodiment, the electrode foil may be formed of a material containing aluminum. An electrode coating system according to another aspect of the present invention includes an electrode surface treatment apparatus according to any one of the above-described embodiments and a coating apparatus configured to form a coating layer on a surface of the electrode foil surface-treated by the electrode surface treatment apparatus.

Advantages of the Invention

[0022] According to the present invention, by performing surface treatment on the electrode foil using plasma to increase the surface energy of the electrode foil, the adhesion between the electrode foil and the electrode mixture can be strengthened, and as a result, the quality of the electrode can be improved.

[0023] In addition, among the electrode active material and the binder contained in the electrode mixture, it is possible to reduce the amount of the binder added for adhesion to the electrode foil and increase the amount of the electrode active material in proportion to the reduced amount of the binder, thereby increasing the capacitance and energy density of the electrode.

[0024] Furthermore, in order to increase the adhesion of the electrode foil, it becomes unnecessary to use an expensive primer foil, so that the manufacturing time of the electrode can be shortened and the manufacturing cost can be reduced.

[0025] Moreover, since surface treatment using plasma is performed during the conveyance of the electrode foil, it is not necessary to separately provide a plasma treatment space, ensuring the continuity of the dry manufacturing process and further shortening the manufacturing time.

[0026] Moreover, by injecting plasma onto a part of the electrode foil that is in contact with and supported by the guide roll, it is possible to prevent deformation and damage such as wrinkles and sags of the electrode foil due to the injection pressure of the plasma, and improve the yield of good products.

[0027] In addition to these, since the electrode surface treatment apparatus according to the present invention performs surface treatment of the electrode foil before the coating process of the electrode foil, it is applicable regardless of the coating method of the electrode, and can be applied to the manufacturing process of wet electrodes as well as the manufacturing process of dry electrodes to improve the quality of the electrodes.

[0028] Furthermore, it should be clearly understood from the following description that those having ordinary knowledge in the technical field to which the present invention pertains can solve various technical problems not mentioned above in various embodiments according to the present invention.

Brief Description of the Drawings

[0029]

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Figure 10

Embodiments for Carrying Out the Invention

[0030] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings in order to clarify the solution corresponding to the technical problem of the present invention. However, when explaining the present invention, if it is recognized that the explanation of the known technology related to the present invention may rather obscure the gist of the present invention, the explanation thereof may be omitted. In addition, the terms used in this specification are terms defined in consideration of the functions in the present invention, and these may possibly differ depending on the intentions or conventions of designers, manufacturers, etc. Therefore, it can be said that it is reasonable to define the definitions of the terms described later based on the content throughout this specification.

[0031] FIG. 1 shows an electrode surface treatment apparatus 100 according to an embodiment of the present invention. As shown in FIG. 1, the electrode surface treatment apparatus 100 according to an embodiment of the present invention may include an unwinder 110, a guide roll 120, and a plasma unit 130.

[0032] The unwinder 110 is configured to unwind the electrode foil E wound in a roll shape and move it in the longitudinal direction (Machine Direction) which is the longitudinal direction of the electrode foil E. The electrode foil E corresponds to the current collector of the electrode, and the material constituting the electrode foil E is not particularly limited as long as it has high conductivity without causing chemical changes in the secondary battery.

[0033] For example, as the material of the electrode foil E, stainless steel, aluminum, nickel, titanium, fired carbon, copper, or a material obtained by surface treatment of the surface of aluminum or stainless steel with carbon, nickel, titanium, silver, etc. can be used.

[0034] In particular, when the electrode foil E corresponds to the current collector of the positive electrode, the electrode foil E can be made of a material containing aluminum. Such an electrode foil E can have a thickness corresponding to the range of 8 μm to 20 μm.

[0035] The guide roll 120 is configured to support the electrode foil E in contact with the electrode foil E moving in the longitudinal direction and guide the movement of the electrode foil E.

[0036] In one embodiment, a plurality of the guide rolls 120 may be provided. For example, the guide roll 120 may include a first guide roll 120A that supports the electrode foil E in contact with the bottom surface of the electrode foil E and a second guide roll 120B that supports the electrode foil E in contact with the upper surface of the electrode foil E.

[0037] The plasma unit 130 is configured to perform surface treatment on the electrode foil E by injecting plasma onto the surface of the electrode foil E while the electrode foil E is moving. For this purpose, the plasma unit 130 may include electrodes that generate a high-voltage arc to generate plasma, a gas inlet that provides gas between these electrodes, a nozzle that injects plasma, and the like. Such a plasma unit 130 may be supported by a support structure 132.

[0038] The plasma injected by the plasma unit 130 is an aggregate of particles including electrons having a negative charge and ions having a positive charge. Such plasma has a fairly high charge separation degree, but since the number of negative and positive charges is the same as a whole, it shows electrical neutrality.

[0039] In one embodiment, the electrode surface treatment apparatus 100 may include a plurality of the plasma units 130. In this case, the plurality of plasma units may be arranged in the longitudinal direction (Machine Direction) that is the longitudinal direction of the electrode foil E, the transverse direction (Transverse Direction) that is the width direction of the electrode foil E, or both the longitudinal and transverse directions to inject plasma onto the surface of the electrode foil E, respectively.

[0040] Generally, foreign substances such as rolling oil remain on the surface of the electrode foil E manufactured by the rolling process. Therefore, the electrode surface treatment apparatus according to the present invention can remove foreign substances remaining on the surface of the electrode foil E, such as rolling oil, and increase the surface energy of the electrode foil E by performing surface treatment on the electrode foil E using plasma.

[0041] Although it will be described again below, the surface-treated electrode foil E' can be conveyed to a coating apparatus (not shown) configured to form a coating layer containing an electrode active material on the surface of the electrode foil E'.

[0042] FIG. 2 shows an electrode surface treatment apparatus 100A according to a modified embodiment of the present invention.

[0043] As shown in FIG. 2, the electrode surface treatment apparatus 100A according to a modified embodiment of the present invention may include an unwinder 110, guide rolls 120, and a plasma unit 130, similar to the electrode surface treatment apparatus 100 shown in FIG. 1. Compared with the electrode surface treatment apparatus 100 shown in FIG. 1, the electrode surface treatment apparatus 100A has differences in terms of the arrangement of the plasma unit 130 and the plasma injection method.

[0044] That is, as described with reference to FIG. 1, the unwinder 110 is configured to unwind the electrode foil E wound in a roll shape and move it in the longitudinal direction (Machine Direction) of the electrode foil E.

[0045] The guide roll 120 is configured to contact the electrode foil E moving in the longitudinal direction, support the electrode foil E, and guide the movement of the electrode foil E.

[0046] The plasma unit 130 is configured to continuously inject plasma onto the surface of the electrode foil E while the electrode foil E is moving to perform surface treatment. Such a plasma unit 130 can be supported by a support structure 132.

[0047] In particular, different from the electrode surface treatment apparatus 100 of FIG. 1, the plasma unit 130 of the electrode surface treatment apparatus 100A may be configured to perform surface treatment by injecting plasma onto a portion of the electrode foil E that is in contact with and supported by the guide roll 120.

[0048] As a result, the tension of the electrode foil E can be maintained even while the plasma is being injected, preventing deformation and damage of the electrode foil such as wrinkles and sags caused by the injection pressure of the plasma, and improving the yield of good products.

[0049] In one embodiment, the electrode surface treatment apparatus 100A may include a plurality of the plasma units 130. In this case, the plurality of plasma units may be arranged in the transverse direction, which is the width direction of the electrode foil E, and configured to inject plasma over the entire width of the electrode foil E.

[0050] Also, in one embodiment, the electrode surface treatment apparatus 100A may include a plurality of the guide rolls 120. In this case, the plurality of guide rolls may include a first guide roll 120A that contacts and supports the electrode foil E on the bottom surface of the electrode foil E, and a second guide roll 120B that contacts and supports the electrode foil E on the upper surface of the electrode foil E.

[0051] In this case, the plurality of plasma units may include at least one first plasma unit 130A that injects plasma onto a first portion of the electrode foil E that is in contact with and supported by the first guide roll 120A, and at least one second plasma unit 130B that injects plasma onto a second portion of the electrode foil E that is in contact with and supported by the second guide roll 120B.

[0052] FIG. 3 shows an electrode surface treatment apparatus 100B according to another modified embodiment of the present invention.

[0053] As shown in FIG. 3, the electrode surface treatment apparatus 100B according to another modified embodiment of the present invention may include a pay - out machine 110, a guide roll 120', and a plasma unit 130, similar to the electrode surface treatment apparatus 100 shown in FIG. 1. Compared with the electrode surface treatment apparatus 100 shown in FIG. 1, the electrode surface treatment apparatus 100B has differences in terms of the structure of the guide roll 120', and the arrangement and plasma injection method of the plasma unit 130.

[0054] That is, as described with reference to FIG. 1, the pay - out machine 110 is configured to pay out the electrode foil E wound in a roll shape and move it in the longitudinal direction (Machine Direction) which is the longitudinal direction of the electrode foil E.

[0055] The guide roll 120' is configured to contact the electrode foil E moving in the longitudinal direction, support the electrode foil E, and guide the movement of the electrode foil E.

[0056] In particular, different from the electrode surface treatment apparatus 100 of FIG. 1, the guide roll 120' of the electrode surface treatment apparatus 100B is configured to have a hollow 122 inside. Further, the guide roll 120' may be provided with a through - hole 124 on its outer surface that communicates with the hollow 122.

[0057] In this case, the through - hole 124 has a certain width W, extends in the transverse direction (Transverse Direction) which is the width direction of the electrode foil E, and may have the shape of a long hole, a slit, or a notch. Thus, the extension length L of the through - hole 124 extending in the transverse direction may be shorter than the width of the electrode foil E to be surface - treated.

[0058] The plasma unit 130 is configured to continuously inject plasma onto the surface of the electrode foil E to perform surface treatment while the electrode foil E is moving.

[0059] In particular, different from the electrode surface treatment apparatus 100 of FIG. 1, the plasma unit 130 of the electrode surface treatment apparatus 100B may be configured to perform surface treatment by injecting plasma onto a part of the electrode foil E that is in contact with and supported by the guide roll 120.

[0060] Further, the plasma unit 130 may be disposed in the hollow of the guide roll 120' and configured to be supported by the guide roll 120'. In this case, the plasma unit 130 may inject plasma onto the surface of the electrode foil E through the through-hole 124 of the guide roll 120'. For this purpose, the guide roll 120' is fixed in a certain posture, different from a normal roll that rotates about a rotation axis. The electrode foil E may be moved in a manner of sliding while contacting the outer surface of the guide roll 120' in which the through-hole 124 is formed.

[0061] Thus, according to the present invention, even while the plasma is being injected, the tension of the electrode foil E is maintained, preventing deformation and damage of the electrode foil such as wrinkles and creases due to the injection pressure of the plasma, and improving the yield of good products. Also, the space required for the arrangement of the plasma unit can be narrowed, and the support structure for supporting the plasma unit can be omitted.

[0062] In one embodiment, the electrode surface treatment apparatus 100B may include a plurality of the plasma units 130. In this case, the plurality of plasma units may be arranged in the transverse direction, which is the width direction of the electrode foil E, and configured to inject plasma over the entire width of the electrode foil E.

[0063] Also, in one embodiment, the electrode surface treatment apparatus 100B may include a plurality of the guide rolls 120'. In this case, the plurality of guide rolls may include a first guide roll 120'A that contacts and supports the electrode foil E on the bottom surface of the electrode foil E, and a second guide roll 120'B that contacts and supports the electrode foil E on the upper surface of the electrode foil E.

[0064] In this case, the plurality of plasma units may include at least one first plasma unit 130A disposed in the hollow of the first guide roll 120’A and at least one second plasma unit 130B disposed in the hollow of the second guide roll 120’B.

[0065] The at least one first plasma unit 130A may inject plasma onto a first portion of the electrode foil E supported in contact with the first guide roll 120’A. Also, the at least one second plasma unit 130B may inject plasma onto a second portion of the electrode foil E supported in contact with the second guide roll 120’B.

[0066] FIG. 4 shows the guide roll 120’ of the electrode surface treatment apparatus 100B shown in FIG. 3.

[0067] As shown in FIG. 4, the guide roll 120’ is configured to support the electrode foil E in contact with the electrode foil E moving in the longitudinal direction and guide the movement of the electrode foil E. In particular, the guide roll 120’ may have a hollow 122 inside and through holes 124 provided on the outer surface.

[0068] The through hole 124 has a constant width W and extends in the transverse direction (X-axis direction) which is the width direction of the electrode foil E, and may be formed in the shape of a long hole, a slit, or a notch. In this case, the extension length L of the through hole 124 may be shorter than the width of the electrode foil E to be surface-treated.

[0069] FIG. 5 shows a cross-sectional view of the guide roll 120’ shown in FIG. 4 taken along the line S1 - S1’.

[0070] As shown in FIG. 5, a plurality of plasma units 130 can be arranged in the hollow 122 of the guide roll 120'. In this case, the plurality of plasma units 130 can be arranged side by side in the lateral direction (X-axis direction). Further, the plasma injection ports of the respective plasma units 130 can be aligned with the through holes 124 of the guide roll 120'.

[0071] In this way, the plasma unit 130 arranged in the hollow 122 of the guide roll 120' can inject plasma onto the surface of the electrode foil E through the through hole 124 formed in the guide roll 120'.

[0072] On the other hand, since the length of the through hole 124 is configured to be shorter than the width of the electrode foil E, the opening at the upper end of the through hole 124 is completely covered by the electrode foil E. As a result, the internal space of the through hole 124 is filled with air excited by plasma.

[0073] For example, a through hole 124 having a depth of about 4 mm to 8 mm and a length shorter than the width of the electrode foil E can be formed on the outer surface of the guide roll 120' to provide a space for connecting the plasma unit 130 and the electrode foil E. The space between the plasma unit 130 and the electrode foil E provided in this way serves as a kind of chamber for accommodating the plasma gas. As a result, uniform plasma treatment can be performed over the entire surface of the electrode foil E facing the opening at the upper end of the through hole 124.

[0074] On the other hand, for surface treatment using plasma, since low-temperature plasma is injected at high pressure, the injection pressure of the plasma pushes up the electrode foil E supported by the outer surface of the guide roll 120' from below, causing tension in the electrode foil E. Therefore, it is possible to prevent deformation and damage such as wrinkles and creases in the electrode foil due to plasma pressure, and improve the yield of good products.

[0075] Although it will be described again below, as described above, the electrode foil E' surface-treated with plasma can be conveyed to a coating apparatus that performs a coating process. Figures 6 and 7 show the surface treatment effect according to the present invention.

[0076] As shown in Figures 6 and 7, in order to analyze the surface treatment effect according to the present invention, a surface energy measurement test using Dyne Ink was conducted. In this test, aluminum electrode foils of the same thickness were used.

[0077] First, as shown in Figure 6, when Dyne Ink of 30 [dyn] or 32 [dyn] is applied to the surface of the aluminum electrode foil before surface treatment, the wettability is relatively good. However, it can be seen that when Dyne Ink of 34 [dyn] or more is applied, the wettability deteriorates significantly.

[0078] On the other hand, as shown in Figure 7, when Dyne Ink is applied to the surface of the aluminum electrode foil surface-treated with plasma according to the present invention, good wettability is shown up to Dyne Ink of 56 [dyn]. That is, it can be seen that the surface energy of the aluminum electrode foil increases significantly through the surface treatment according to the present invention.

[0079] In this way, by increasing the surface energy of the aluminum electrode foil, the adhesion between the electrode foil and the electrode mixture is strengthened, and as a result, the quality of the electrode can be improved. Also, among the electrode active material and the binder contained in the electrode mixture, it becomes possible to reduce the amount of the binder added to increase the adhesion, and increase the amount of the electrode active material in proportion to the reduced amount of the binder, thereby increasing the capacitance and energy density of the electrode. Further, since it becomes unnecessary to use an expensive primer foil to increase the adhesion of the electrode foil, the manufacturing time of the electrode can be shortened and the manufacturing cost can be reduced.

[0080] Figure 8 shows, as a block diagram, an electrode coating system 2 according to an embodiment of the present invention.

[0081] As shown in Figure 8, an electrode coating system 2 according to an embodiment of the present invention may include an electrode surface treatment apparatus 10 corresponding to any one of the above-described electrode surface treatment apparatuses 100, 100A, and 100B, and a coating apparatus 20.

[0082] As described above, the electrode surface treatment apparatus 10 can perform surface treatment on the electrode foil E by plasma and deliver the surface-treated electrode foil E' to the coating apparatus 20.

[0083] The coating apparatus 20 may be configured to form a coating layer by applying coating processes in various ways to the surface of the surface-treated electrode foil E'. For example, the coating apparatus 20 may apply a dry coating process or a wet coating process to form a coating layer on the surface of the electrode foil E'.

[0084] Figure 9 shows an electrode coating system 2A according to an embodiment of the present invention. As shown in Figure 9, an electrode coating system 2A according to an embodiment of the present invention may include an electrode surface treatment apparatus 10 corresponding to any one of the above-described electrode surface treatment apparatuses 100, 100A, and 100B, and a coating apparatus 20A.

[0085] As described above, the electrode surface treatment apparatus 10 can perform surface treatment on the electrode foil E by plasma and deliver the surface-treated electrode foil E' to the coating apparatus 20A.

[0086] The coating device 20A may be configured to form a coating layer by applying a dry coating process to the surface of the surface-treated electrode foil E'. For this purpose, the coating device 20A may include a transport roller 22 for transporting the electrode foil E', a feeder 24 for supplying a powdery electrode mixture containing an electrode active material to the surface of the electrode foil E', a rolling roller 26 for crimping the electrode mixture to the surface of the electrode foil E', and a rewinder 28 for winding the coated electrode CE in a roll shape, etc.

[0087] On the other hand, the electrode mixture used in the production of the dry electrode may contain an electrode active material and a polymer binder, and may further contain a conductive material, a filler, etc. according to the embodiment.

[0088] The electrode active material may be composed of a positive electrode active material or a negative electrode active material according to the polarity of the dry electrode to be manufactured.

[0089] The positive electrode active material may include a lithium transition metal oxide; an oxide of lithium metal iron; a lithium nickel-manganese-cobalt oxide; an oxide in which a part of the lithium nickel-manganese-cobalt oxide is substituted with another transition metal; or two or more of these, but is not limited thereto. For example, the positive electrode active material may be, for example, a layered compound such as lithium cobalt oxide (LiCoO2), lithium nickel oxide (LiNiO2), or a compound substituted with one or more transition metals; the chemical formula Li 1+x Mn 2-x O4 (where x is 0 to 0.33), lithium manganese oxides such as LiMnO3, LiMn2O3, LiMnO2; lithium copper oxide (Li2CuO2); vanadium oxides such as LiV3O8, LiV3O4, V2O5, Cu2V2O7; the chemical formula LiNi 1-x M x O2 (where M = Co, Mn, Al, Cu, Fe, Mg, B or Ga, and x = 0.01 to 0.3) represented by Ni-site type lithium nickel oxide; the chemical formula LiMn 2-x M xLithium manganese composite oxides represented by O2 (where M = Co, Ni, Fe, Cr, Zn or Ta, and x = 0.01 to 0.1) or Li2Mn3MO8 (where M = Fe, Co, Ni, Cu or Zn); Oxides LiMPO4 of lithium metal (where M = Fe, CO, Ni, or Mn); Lithium nickel-manganese-cobalt oxide Li 1+x (Ni a Co b Mn c ) 1-x O2 (x = 0 to 0.03, a = 0.3 to 0.95, b = 0.01 to 0.35, c = 0.01 to 0.5, a + b + c = 1); Oxides in which part of the lithium nickel-manganese-cobalt oxide is substituted with aluminum Li a [Ni b Co c Mn d Al e 1-f M1 f O2 (M1 is any one or more selected from the group consisting of Zr, B, W, Mg, Ce, Hf, Ta, La, Ti, Sr, Ba, F, P and S, 0.8 ≦ a ≦ 1.2, 0.5 ≦ b ≦ 0.99, 0 < c < 0.5, 0 < d < 0.5, 0.01 ≦ e ≦ 0.1, 0 ≦ f ≦ 0.1); Oxides in which part of the lithium nickel-manganese-cobalt oxide is substituted with other transition metals Li 1+x (Ni a Co b Mn c M d ) 1-x O2 (x = 0 to 0.03, a = 0.3 to 0.95, b = 0.01 to 0.35, c = 0.01 to 0.5, d = 0.001 to 0.03, a + b + c + d = 1, M is any one selected from the group consisting of Fe, V, Cr, Ti, W, Ta, Mg and Mo), disulfide compounds; Examples include Fe2(MoO4)3, etc., but the present invention is not limited thereto at all.

[0090] The negative electrode active material is, for example, carbon such as graphitizable carbon and graphite-based carbon; Li x Fe2O3 (0 ≦ x ≦ 1), Li x WO2 (0 ≦ x ≦ 1), Sn​x Me 1-x Me’ y O z (Me: Mn, Fe, Pb, Ge; Me’: Al, B, P, Si, Group 1, 2, 3 elements of the periodic table, halogen; 0 ≦ x ≦ 1; 1 ≦ y ≦ 3; 1 ≦ z ≦ 8) and other metal composite oxides; lithium metal; lithium alloy; silicon-based alloy; tin-based alloy; silicon-based oxides such as SiO, SiO / C, SiO2; metal oxides such as SnO, SnO2, PbO, PbO2, Pb2O3, Pb3O4, Sb2O3, Sb2O4, Sb2O5, GeO, GeO2, Bi2O3, Bi2O4 and Bi2O5; conductive polymers such as polyacetylene; Li-Co-Ni-based materials; or may include two or more of these, but the present invention is not limited thereto in any way.

[0091] The polymer binder may include polytetrafluoroethylene (PTFE: Polytetrafluoroethylene), polyolefin, or a mixture thereof. For example, the binder polymer may contain 60% by weight or more of the PTFE based on the total weight. At this time, the binder polymer may further contain any one or more of polyethylene oxide (PEO: polyethylene oxide), vinylidene fluoride (PVdF: polyvinylidene fluoride), vinylidene fluoride - hexafluoropropylene copolymer (PVdF-HFP: Polyvinylidene fluoride-co-hexafluoropropylene), and polyolefin-based polymers.

[0092] The conductive material may include a substance having conductivity without causing a chemical change in the secondary battery. For example, the conductive material may be graphite such as natural graphite or artificial graphite; carbon black such as carbon black, acetylene black, ketjen black, channel black, furnace black, lamp black, thermal black; conductive fibers such as carbon fibers and metal fibers; metal powders such as carbon fluoride, aluminum, and nickel powder; conductive whiskers such as zinc oxide and potassium titanate; conductive metal oxides such as titanium oxide; conductive materials such as polyphenylene derivatives; or any two or more of these. The conductive material may include any one or more selected from the group consisting of activated carbon, graphite, carbon black, and carbon nanotubes for uniform mixing and improvement of conductivity. On the other hand, considering the manufacturing process of the electrode binder for the electrode, since it is difficult to achieve a high degree of dispersion for linear conductive materials such as carbon fibers, it may be contained in the powder to a minimum extent or may not be contained at all.

[0093] The filler is a component that suppresses the expansion of the electrode and may include a fibrous material that does not cause a chemical change in the secondary battery. For example, the filler may include olefin polymers such as polyethylene and polypropylene; fibrous substances such as glass fibers and carbon fibers; or two or more of these.

[0094] FIG. 10 shows an electrode coating system 2B according to another embodiment of the present invention.

[0095] As shown in FIG. 10, the electrode coating system 2B according to another embodiment of the present invention may include an electrode surface treatment device 10 corresponding to any one of the above-described electrode surface treatment devices 100, 100A, and 100B, and a coating device 20B.

[0096] As described above, the electrode surface treatment device 10 can perform surface treatment on the electrode foil E by plasma and deliver the surface-treated electrode foil E' to the coating device 20B.

[0097] The coating device 20B can be configured to form a coating layer by applying a dry coating process to the surface of the surface-treated electrode foil E'.

[0098] For this purpose, the coating device 20B may include a transport roller 22B for transporting the electrode foil E', an extruder 24B for generating an electrode film C for coating by pressing or extruding a powdery electrode mixture containing an electrode active material, a laminating roller 26B for pressing the electrode film onto the surface of the electrode foil E', and a rewinder 28B for winding the coated electrode CE into a roll.

[0099] On the other hand, FIG. 10 shows as an example the generation of an electrode film through the extruder 24B. However, such an electrode film can also be generated by a method of pressing a powdery electrode mixture with a plurality of calendering rollers.

[0100] As described above, according to the present invention, by performing surface treatment on the electrode foil using plasma to increase the surface energy of the electrode foil, the adhesion between the electrode foil and the electrode mixture can be strengthened, and as a result, the quality of the electrode can be improved.

[0101] In addition, among the electrode active material and the binder contained in the electrode mixture, it becomes possible to reduce the amount of the binder added for adhesion to the electrode foil and increase the amount of the electrode active material in proportion to the reduced amount of the binder, thereby increasing the capacity and energy density of the electrode.

[0102] Furthermore, in order to increase the adhesion of the electrode foil, it is not necessary to use an expensive primer foil, so that the manufacturing time of the electrode can be shortened and the manufacturing cost can be reduced.

[0103] Furthermore, by performing surface treatment using plasma during the conveyance of the electrode foil, it is not necessary to separately provide a plasma treatment space, ensuring the continuity of the dry manufacturing process and further shortening the manufacturing time.

[0104] Furthermore, by injecting plasma onto a part of the electrode foil that is in contact with and supported by the guide roll, it is possible to prevent deformation and damage such as wrinkles and kinks in the electrode foil due to the plasma injection pressure, and improve the yield of good products.

[0105] In addition to these, since the electrode surface treatment apparatus according to the present invention performs surface treatment of the electrode foil before the coating process of the electrode foil, it can be applied regardless of the coating method of the electrode, and can be applied not only to the manufacturing process of dry electrodes but also to the manufacturing process of wet electrodes to improve the quality of the electrodes.

[0106] Furthermore, it goes without saying that the embodiments according to the present invention can solve various other technical problems in the technical fields related to the present invention as well as the present technical field, excluding the content mentioned in this specification.

[0107] So far, the present invention has been described with reference to specific embodiments. However, it should be clearly understood by those skilled in the art that various modified embodiments can be realized within the technical scope of the present invention. Therefore, the embodiments disclosed above should be considered from an explanatory perspective rather than a limiting perspective. That is, the true technical idea scope of the present invention is shown in the claims, and all differences within the equivalent scope thereof should be construed as being included in the present invention.

Explanation of Reference Numerals

[0108] 2A, 2B Electrode Coating System 10 Electrode Surface Treatment Apparatus 20, 20A, 20B Coating Apparatus 22, 22B Conveying Roller 24 Feeders 24B Extruder 26 Calendering Rollers 26B Laminating Rollers 28, 28B Rewinders 100, 100A, 100B Electrode Surface Treatment Devices 110 Unwinder 120, 120A, 120B Guide Rollers 122 Hollow 124 Through-Hole 130, 130A, 130B Plasma Units 132 Support Structure

Claims

1. A guide roll configured to support an electrode foil by contacting the electrode foil that moves in the longitudinal direction (Machine Direction) and to guide the movement of the electrode foil, A plasma unit configured to perform surface treatment on the electrode foil by injecting plasma onto the electrode foil while the electrode foil is moving, An electrode surface treatment apparatus comprising the above.

2. The electrode surface treatment apparatus according to claim 1, wherein the plasma unit is configured to inject plasma onto a part of the electrode foil that is in contact with and supported by the guide roll.

3. The electrode surface treatment apparatus according to claim 1, comprising a plurality of the plasma units, wherein the plurality of plasma units are arranged in the transverse direction (Transverse Direction) and are each configured to inject plasma onto the electrode foil.

4. Comprising a plurality of the guide rolls, The plurality of guide rolls include A first guide roll that contacts and supports the electrode foil on the bottom surface of the electrode foil, A second guide roll that contacts and supports the electrode foil on the upper surface of the electrode foil, The electrode surface treatment apparatus according to claim 1.

5. Comprising a plurality of the plasma units, The plurality of plasma units include At least one first plasma unit configured to inject plasma onto a first part of the electrode foil that is in contact with and supported by the first guide roll, At least one second plasma unit configured to inject plasma onto a second part of the electrode foil that is in contact with and supported by the second guide roll, The electrode surface treatment apparatus according to claim 4.

6. The guide roll has a hollow inside, The electrode surface treatment apparatus according to claim 1, wherein the plasma unit is disposed in the hollow of the guide roll.

7. The guide roll is provided with a through hole on an outer surface of the guide roll that communicates with the hollow, The electrode surface treatment apparatus according to claim 6, wherein the plasma unit is configured to inject plasma onto the surface of the electrode foil through the through hole.

8. The electrode surface treatment apparatus according to claim 7, wherein the through hole has a constant width and has a shape of a long hole or a slit that extends in the transverse direction (Transverse Direction).

9. The electrode surface treatment apparatus according to claim 8, wherein the length of the through hole extending in the lateral direction is shorter than the width of the electrode foil.

10. Including a plurality of the guide rolls and a plurality of the plasma units respectively, At least one first plasma unit among the plurality of plasma units is disposed in the hollow of a first guide roll among the plurality of guide rolls, The electrode surface treatment apparatus according to claim 6, wherein at least one second plasma unit among the plurality of plasma units is disposed in the hollow of a second guide roll among the plurality of guide rolls.

11. Further including an unwinder configured to unwind the electrode foil wound in a roll shape and move it in the longitudinal direction, The electrode surface treatment apparatus according to claim 1, wherein the guide roll is configured to guide the electrode foil moved by the unwinder.

12. The electrode surface treatment apparatus according to claim 1, wherein the electrode foil is formed of a material containing aluminum.

13. An electrode surface treatment apparatus according to any one of claims 1 to 12, A coating device configured to form a coating layer on the surface of the electrode foil surface-treated by the electrode surface treatment apparatus, An electrode coating system including the above.

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