Plasma processing apparatus and secondary battery laminating system including the same

Abstract

The plasma processing apparatus for a unit cell of a secondary battery according to an embodiment of the present invention includes a discharge roller that transfers a separator of the unit cell of the secondary battery and houses a metal member, and a plasma processing member that generates plasma by mutual reaction with the metal member and irradiates the surface of the separator, and a pattern portion is formed on the outer surface of the discharge roller so as to have a predetermined step.

Description

Technical Field

[0001] The present invention relates to a plasma processing apparatus and a laminate system for a secondary battery including the same, and more particularly, to a plasma processing apparatus for improving wettability by adjusting the adhesive force between a separator and an electrode, and a laminate system for a secondary battery including the same.

[0002] This application claims priority based on Korean Patent Application No. 10-2022-0111700 filed on September 2, 2022, and all of the content disclosed in the specification and drawings of the application is incorporated into this application.

Background Art

[0003] Generally, a secondary battery, unlike a primary battery that cannot be charged, refers to a battery that can be charged and discharged, and such secondary batteries are widely used in the field of advanced electronic devices such as mobile phones, notebook PCs, and camcorders.

[0004] And secondary batteries are divided into cylindrical secondary batteries in which an electrode assembly is built into a metal can, pouch-type secondary batteries in which an electrode assembly is built into a pouch, or prismatic secondary batteries, etc. The pouch-type secondary battery includes an electrode assembly, an electrolytic solution, and a pouch for accommodating the electrode assembly and the electrolytic solution. And, in the electrode assembly, a positive electrode and a negative electrode are arranged with a separator interposed therebetween, electrode tabs are respectively attached to the positive electrode and the negative electrode, and electrode leads are respectively coupled to the electrode tabs.

[0005] On the other hand, the pouch-type secondary battery performs a lamination process to enhance the adhesiveness of an electrode assembly in which an electrode and a separator are laminated.

[0006] However, in the manufacturing process of conventional polymer cells, due to processability, bicells are laminated at a constant temperature / pressure, so there is a problem that the wettability at the interface between the electrode and the separator decreases.

[0007] That is, when the adhesive force at the interface between the electrode and the separator is constant and the electrode and the separator are uniformly and completely adhered as a whole, it is difficult for the electrolyte to penetrate between the electrode and the separator, so it is difficult to fully exhibit the performance of the secondary battery.

[0008] In particular, in the case of the same process conditions, there is a problem that the adhesive force at the interface between the positive electrode and the separator is stronger and the decrease in wettability becomes more significant, and the resulting performance degradation of the secondary battery also becomes prominent.

[0009] Also, when the adhesive force between the electrode and the separator interfaces is generally uniformly high in this way, there is also a problem that it becomes difficult to smoothly discharge the gas generated in the formation process during the manufacturing process of the secondary battery. If the gas is not smoothly discharged accordingly, there is a problem that the lithium plating phenomenon occurs.

Summary of the Invention

Problems to be Solved by the Invention

[0010] The present invention has been made in view of the above problems, and by partially weakening the adhesive force between the electrode and the separator of the unit cell used in the manufacture of the secondary battery or providing a non-adhered region, a plasma processing apparatus that improves the wettability of the electrolyte and a laminate system for a secondary battery including the same are provided.

[0011] Another object of the present invention is to provide a plasma processing apparatus that can minimize the lithium plating phenomenon by guiding the smooth discharge of the gas in the unit cell and a laminate system for a secondary battery including the same.

[0012] However, the technical problems to be solved by the present invention are not limited to the above problems, and other problems not mentioned will be clearly understood by those skilled in the art from the following description of the invention.

Means for Solving the Problems

[0013] To achieve the above object, the present invention provides a plasma processing apparatus for a unit cell of a secondary battery, including a discharge roller that transfers a separation membrane of the unit cell of the secondary battery and incorporates a metal member, and a plasma processing member that generates plasma by mutual reaction with the metal member and irradiates the surface of the separation membrane. A pattern portion may be formed on the outer surface of the discharge roller so as to have a predetermined step.

[0014] Desirably, the pattern portion may include a contact portion that is in close contact with the separation membrane during transfer of the separation membrane, and a non-contact portion that has a step of a predetermined depth from the contact portion and is separated from the separation membrane by a predetermined distance.

[0015] Desirably, when the plasma of the plasma processing member is irradiated, an adhesion region is formed on the surface of the separation membrane disposed on the contact portion side, and an unadhered region is formed on the surface of the separation membrane disposed on the non-contact portion side.

[0016] Desirably, the pattern portion may include a connecting portion that connects the contact portion and the non-contact portion.

[0017] Desirably, the contact portion and the non-contact portion may be alternately arranged on the outer surface of the discharge roller.

[0018] Desirably, the contact portion and the non-contact portion may be provided in at least one of the longitudinal direction and the width direction of the discharge roller.

[0019] Desirably, the non-contact portion may be formed to be recessed by a predetermined depth from the outer surface of the discharge roller.

[0020] Desirably, the depth of the recess of the non-contact portion may be 2 mm.

[0021] Desirably, the pattern portion may include a plurality of patterns having different lengths or widths.

[0022] Desirably, the plurality of patterns may have different recess depths.

[0023] Desirably, the pattern portion may be provided in a mosaic shape.

[0024] The present invention further includes a laminate system for a secondary battery, characterized by including the plasma processing apparatus according to the above-described embodiment.

Advantages of the Invention

[0025] According to various embodiments of the present invention as described above, by making the adhesion force between the electrode and the separator of the unit cell used in the production of the secondary battery partially weak or by providing a non-adhesive region, a plasma processing apparatus in which the wettability of the electrolytic solution is improved and a laminate system for a secondary battery including the same can be provided.

[0026] Also, according to various embodiments of the present invention as described above, a plasma processing apparatus capable of minimizing the lithium plating phenomenon by guiding the smooth discharge of gas in the unit cell and a laminate system for a secondary battery including the same can be provided.

[0027] In addition, according to various embodiments of the present invention, other additional effects can be achieved. Such various effects of the present invention will be described in detail in each embodiment, and the description of effects that can be easily understood by those skilled in the art will be omitted.

[0028] The following drawings attached to this specification illustrate preferred embodiments of the present invention and serve to further understand the technical idea of the present invention together with the detailed description of the invention. Therefore, the present invention should not be construed as being limited only to the matters described in the drawings.

Brief Description of the Drawings

[0029]

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Mode for Carrying Out the Invention

[0030] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Prior to this, the terms and words used in this specification and the claims should not be construed as being limited to their ordinary or dictionary meanings. The inventor himself must interpret them in accordance with the meaning and concept corresponding to the technical idea of the present invention in accordance with the principle that he can appropriately define the concept of the terms in order to explain the invention in the best way.

[0031] Therefore, it should be understood that the embodiments described in this specification and the configurations shown in the drawings are only one of the most preferred embodiments of the present invention and do not represent all of the technical ideas of the present invention. At the time of this application, there may be various equivalents and modifications that can replace them.

[0032] FIG. 1 and FIG. 2 are diagrams showing a unit cell for a secondary battery according to an embodiment of the present invention, and FIG. 3 and FIG. 4 are diagrams showing a positive electrode and a negative electrode applied to the unit cell for a secondary battery according to an embodiment of the present invention.

[0033] Referring to FIGS. 1 to 4, a unit cell for a secondary battery according to an embodiment of the present invention includes a central electrode having a first polarity, a pair of separator films 3 laminated on both sides of the central electrode respectively, and an upper electrode and a lower electrode of a second polarity laminated on the pair of separator films respectively and opposite to the first polarity.

[0034] A unit cell configured such that the electrodes located on the outermost periphery have the same polarity as each other is usually called a bicell.

[0035] Such a bicell-type unit cell can be divided into a positive electrode type bicell in which the upper electrode and the lower electrode are the positive electrode 1 and the central electrode is the negative electrode 2 as shown in FIG. 1, and a negative electrode type bicell in which the upper electrode and the lower electrode are the negative electrode 2 and the central electrode is the positive electrode 1 as shown in FIG. 2.

[0036] A secondary battery configured using such bicells may have a form in which the positive electrode bicells and the negative electrode bicells are alternately stacked with a separator interposed therebetween. As such a stacking method of the bicells, a simple stacking method, a stacking / folding method, etc. may be applied.

[0037] The positive electrode 1 applied to the unit cell for a secondary battery according to an embodiment of the present invention is configured to include a positive electrode current collector 1a and a positive electrode active material 1b laminated on the surface thereof, as shown in FIG. 3.

[0038] As the positive electrode current collector 1a, a foil made of aluminum, nickel, or a combination of these substances may be used.

[0039] As the positive electrode active material 1b, a normal positive electrode active material used for the positive electrode of a secondary battery in the art can be used. Non-limiting examples thereof include LiCoO2, LiNiO2, LiMnO2, LiMn2O4, Li(Ni a Co b Mn c )O2 (0 < a < 1, 0 < b < 1, a + b + c = 1), LiNi 1-Y Co Y O2, LiCo 1-y Mn y O2, LiNi 1-y Mn y O2 (0 ≤ y < 1), Li(Ni a Co b Mn c )O4 (0 < a < 2, 0 < b < 2, a + b + c = 2), LiMn 2-z Ni z O4, LiMn 2-Z Co Z O4 (where 0 < Z < 2), LiCoPO4, LiFePO4, and mixtures thereof.

[0040] Also, the negative electrode 2 applied to the unit cell for a secondary battery according to an embodiment of the present invention is configured to include a negative electrode current collector 2a and a negative electrode active material 2b laminated on the surface thereof, as shown in FIG. 4.

[0041] As the negative electrode current collector 2a, a foil made of stainless steel, nickel, copper, titanium, or an alloy thereof can be used.

[0042] As the negative electrode active material 2b, ordinary negative electrode active materials used for the negative electrode of a secondary battery in the art can be used. Non-limiting examples thereof include carbon such as graphitizable carbon and graphite 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, Group 2, Group 3 elements of the periodic table, halogen; 0 < x ≦ 1; 1 ≦ y ≦ 3; 1 ≦ z ≦ 8), etc. metal composite oxides; lithium metal; lithium alloy; silicon-based alloy; tin-based alloy; 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, etc. can be used.

[0043] On the other hand, the separator 3 interposed between the positive electrode 1 and the negative electrode 2 can be embodied to include a porous coating layer formed on one or both surfaces of a porous polymer substrate.

[0044] The porous polymer substrate used for the separator 3 is not particularly limited as long as it is a planar porous polymer substrate usually applied to a secondary battery. The porous polymer substrate can be in the form of a film or a non-woven fabric.

[0045] The porous coating layer is formed on one or both sides of a porous polymer substrate. Inorganic particles are connected and fixed by a binder polymer for the porous coating layer, and micro-scale pores are formed by the interstitial volume between the inorganic particles. The binder polymer for the porous coating layer is not particularly limited as long as it has excellent binding force with inorganic particles and is hardly dissolved by an electrolytic solution.

[0046] On the other hand, in a unit cell for a secondary battery according to an embodiment of the present invention, the adhesive force is not uniformly formed at the interface between the positive electrode 1 and the separator 3 and / or at the interface between the negative electrode 2 and the separator 3, and has a patterned adhesive force. That is, the interfaces of the electrodes 1 and 2 with the separator 3 have different adhesive forces for different regions, so that the degree of adhesion between the electrodes 1 and 2 and the separator 3 is different for different regions. A method for forming such a patterned adhesive force will be described in more detail with reference to the following drawings.

[0047] FIG. 5 is a diagram schematically showing a laminate system for a secondary battery for manufacturing a unit cell according to the present invention.

[0048] Referring to FIG. 5, the laminate system 10 for a secondary battery may include a central electrode supply roller 100, a plasma treatment device 200, an upper electrode supply roller 320, a lower electrode supply roller 330, a heater unit 400, a laminate roller 500, and cutter units 610, 620, 630, and 640.

[0049] The central electrode supply roller 100 may supply a central electrode E1 for manufacturing a unit cell. For this purpose, a long fabric-shaped central electrode E1 that can supply the central electrode E1 is wound around the central electrode supply roller 100.

[0050] The plasma processing apparatus 200 is for enhancing the adhesiveness, electrolyte impregnation property, and gas exhaust property of unit cells which are basic units. By supplying separation membranes S1 and S2 onto both surfaces of the central electrode E1 and subjecting the surfaces of the supplied separation membranes S1 and S2 to plasma processing, the adhesion force with the electrodes E1, E2, and E3 can be enhanced by surface modification of the separation membranes S1 and S2.

[0051] Hereinafter, the plasma processing apparatus 200 of the laminate system 10 for the secondary battery will be described more specifically.

[0052] FIG. 6 is a diagram showing the plasma processing apparatus of the laminate system for the secondary battery in FIG. 5, FIG. 7 is a schematic perspective view of the plasma processing apparatus in FIG. 6, FIG. 8 is a schematic perspective view showing the passing state of the separation membrane in the plasma processing apparatus in FIG. 6, and FIG. 9 is a cross-sectional view of the main part of the plasma processing apparatus in FIG. 8.

[0053] Referring to FIGS. 6 to 9, the plasma processing apparatus 200 may include discharge rollers 220 and 230 that transfer the separation membranes S1 and S2 of the unit cell for the secondary battery and in which a metal member 240 is incorporated, and a plasma processing member 260 that generates plasma by mutual reaction with the metal member 240 and irradiates the surfaces of the separation membranes S1 and S2. Here, a pattern portion 250 (see FIGS. 7 to 9) may be formed on the outer surfaces of the discharge rollers 220 and 230 so as to have a predetermined step.

[0054] In the case of the plasma processing apparatus 200 according to the present embodiment, by the pattern portion 250 provided so as to have a predetermined step formed on the outer surfaces of the discharge rollers 220 and 230, patterned plasma processing can be performed such that plasma processing is performed on a partial region of the surfaces of the separation membranes S1 and S2 and the plasma processing is not performed on the remaining regions. That is, the plasma processing apparatus 200 can activate a uniform and patterned adhesion force on the surfaces of the separation membranes S1 and S2 so that the electrodes E1, E2, and E3 and the separation membranes S1 and S2 are pattern-bonded.

[0055] The discharge rollers 220 and 230 may include a first discharge roller 220 and a second discharge roller 230.

[0056] The first discharge roller 220 is for transporting one separation membrane S1 and may be provided with the metal member 240 inside. The second discharge roller 230 is for transporting another separation membrane S2 and may be provided with the metal member 240 inside.

[0057] The plasma treatment member 260 is provided so as to be separated from the separation membranes S1 and S2, and can generate plasma P by mutual reaction with the metal member 240 and irradiate the surfaces of the separation membranes S1 and S2.

[0058] Such a plasma treatment member 260 may include a treatment member main body 261, an electrode piece 264, and a switch 265.

[0059] The treatment member main body 261 is provided so as to be separated from each of the separation membranes S1 and S2 and may be provided in the width direction of the separation membranes S1 and S2. Such a treatment member main body 261 may be made of a non-metallic material, thereby preventing the generation of resistance between the metal member 240 and the electrode piece 264. As a result, plasma P can be stably generated between the metal member 240 and the treatment member main body 261.

[0060] The treatment member main body 261 may be provided as a ceramic among non-metallic materials. The ceramic is a non-metallic inorganic material obtained through a heat treatment process, has heat resistance, high strength, and corrosion resistance, and in particular, can improve the efficiency of use because it is light.

[0061] The electrode piece 264 may be a corona discharge electrode, and the corona discharge electrode can stably generate plasma P between the metal member 240 and the treatment member main body 261.

[0062] The electrode sheet 264 may be formed from a plurality of unit electrode sheets. The plurality of unit electrode sheets may be connected along the width direction of the separation membranes S1 and S2 on the processing member body 261 to form one electrode sheet 264, whereby it can be used compatibly with separation membranes having various widths.

[0063] On the other hand, the plurality of unit electrode sheets may be provided separately along the width direction of the separation membranes S1 and S2 on the body 261 of the processing member. Due to such a feature, plasma P can be partially generated between the metal member 240 and the processing member body 261. As a result, it is possible to implement a patterned adhesive force on the surfaces of the separation membranes S1 and S2.

[0064] The plurality of unit electrode sheets may be provided with the same length, width, and thickness as each other, or one or more of the length, width, and thickness may be different. As a result, it is possible to implement adhesive forces with various patterns on the surfaces of the separation membranes S1 and S2.

[0065] On the other hand, the processing member body 261 forms an insertion groove 263 that is long in the width direction of the separation membranes S1 and S2. The electrode sheet 264 can be inserted and fixed in the insertion groove 263, whereby damage to the electrode sheet 264 from external objects can be prevented. As a result, plasma P can be stably generated.

[0066] The switch 265 can apply power to the electrode sheet 264. The switch 265 can easily adjust the use or non-use of the electrode sheet 264 by controlling the power supplied to the electrode sheet 264. As a result, wasteful power consumption can be prevented.

[0067] In the plasma processing member 260 having such a configuration, plasma P is generated while the metal member 240 and the electrode sheet 264 correspond to each other, and the plasma P is irradiated onto the surfaces of the separation membranes S1 and S2 between the metal member 240 and the electrode sheet 264 to implement an adhesive force on the separation membranes S1 and S2.

[0068] Hereinafter, a specific configuration for realizing the adhesive force patterned by the plasma processing apparatus 200 according to the present embodiment and the mechanism related thereto will be described in more detail.

[0069] The pattern portion 250 is formed on the surface 221 of the discharge roller 220 and can be provided in a mosaic shape. Although not shown, the pattern portion 250 is also formed on the surface of the second discharge roller 230 that transfers the other separation film S2, of course. On the other hand, in the following description, for the sake of convenience of explanation, the description will be centered on the pattern portion 250 provided on the first discharge roller 220 corresponding to the one separation film S1.

[0070] Such a pattern portion 250 may include a contact portion 252 and a non-contact portion 254.

[0071] The contact portion 252 is provided on the surface of the discharge roller 220 and can be in close contact with the separation film S1 when the separation film S1 is transferred. The non-contact portion 254 has a step of a predetermined depth h from the contact portion 252 and can be separated from the separation film S1 by a predetermined distance.

[0072] For this purpose, the non-contact portion 254 can be formed to be recessed from the outer surface 221 of the discharge roller 220 by a predetermined depth h. For example, the depth of the recess of the non-contact portion 254 can be approximately 2 mm.

[0073] The contact portion 252 and the non-contact portion 254 are alternately arranged on the outer surface of the discharge roller 220, specifically, the first discharge roller 220, and a predetermined pattern can be formed on the surface of the discharge roller 220. The predetermined pattern can be provided in various ways according to design conditions preset according to the form and size of the separation film S1 and the like.

[0074] For example, the contact portion 252 and the non-contact portion 254 may be provided in at least one of the longitudinal direction and the width direction of the discharge roller 220. Also, a plurality of the contact portions 252 and the non-contact portions 254 may be provided. The plurality of contact portions 252 may be spaced apart from each other by a predetermined distance and may have a preset separation distance. The plurality of non-contact portions 254 are formed by etching from the outer surface 221 of the discharge roller 220 and may have a preset etching length, etching width, and etching depth. At least a part of the plurality of non-contact portions 254 may have different etching lengths and etching widths.

[0075] Depending on various arrangements and shapes of the contact portion 252 and the non-contact portion 254 as described above, various patterns can be embodied on the surface 221 of the discharge roller 220, and it is also applicable to separation membranes S1 of various sizes, and various adhesive forces of patterns can be embodied according to required designs and the like.

[0076] The pattern portion 250 may include a connecting portion 256 that connects the contact portion 252 and the non-contact portion 254. The connecting portion 256 may guide while connecting the contact portion 252 and the non-contact portion 254 to form a pattern in a concavo-convex form on the pattern portion 250.

[0077] Therefore, in this embodiment, the pattern portion 250 formed on the surface 221 of the first discharge roller 220 can divide the separation membrane S1 transferred on the first discharge roller 220 into a region that adheres to the pattern portion 250 and a region that is separated from the pattern portion 250. In the separation membrane S1, the region that adheres to the pattern portion 250 is the region disposed on the contact portion 252, and the region that is separated from the pattern portion 250 may be the region disposed on the non-contact portion 254.

[0078] Here, since the region of the separation film S1 disposed on the contact portion 252 is in closer contact with the first discharge roller 220 than the region of the separation film S1 disposed on the non-contact portion 254, when the plasma P is irradiated, a smoother interaction with the metal member 240 can be realized, and thus an adhesion region having a high adhesion force region can be formed. On the other hand, since the region of the separation film S1 disposed on the non-contact portion 254 is separated from the surface of the first discharge roller 220, when the plasma P is irradiated, the interaction with the metal member 240 becomes weak, and a non-adhesion region having a low adhesion force region is realized.

[0079] In this way, through the pattern portion 250, when the plasma of the plasma processing member 260 is irradiated, an adhesion region A1 is formed on the surface of the separation film S1 disposed on the contact portion 252 side, and a non-adhesion region A2 may be formed on the surface of the separation film disposed on the non-contact portion 254 side.

[0080] The adhesion region A1 and the non-adhesion region A2 are alternately arranged, and thereby, a patterned adhesion force having a mosaic shape in which the adhesion region A1 and the non-adhesion region A2 are alternately formed may be obtained.

[0081] Accordingly, the plasma processing apparatus 200 according to the present embodiment can form a mask having a patterned adhesion force by forming an adhesion region A1 and a non-adhesion region A2 on the surfaces of the separation films S1 and S2 by the pattern portion 250 formed on the surfaces of the discharge rollers 220 and 230.

[0082] Adhesion between substances can be divided into chemical adhesion and mechanical interlocking. The improvement of adhesion force by plasma treatment as in the present application is a phenomenon that occurs due to the strengthening of chemical adhesion force among them. Types of chemical adhesion include electrostatic attraction, chemical absorption, chemical bonding, etc. When a part of the surface of the separation membrane S1 is treated with plasma P as in the present invention, in the region A1 treated with plasma P, for example, bonding structures such as C-H, C=C, C-C are changed to bonding structures such as C-O, C=O, O-C-O, O-C=O, etc. through surface modification, so that such electrostatic attraction, chemical absorption, chemical bonding, etc. are strengthened. On the other hand, in the region A2 not treated with such plasma P, the adhesion force is relatively inferior, and the impregnation property of the electrolytic solution is improved in this region.

[0083] FIG. 10 is a diagram for explaining a plasma treatment apparatus according to another embodiment of the present invention.

[0084] Since the plasma treatment apparatus 205 according to the present embodiment is similar to the plasma treatment apparatus 200 of the foregoing embodiment, duplicate descriptions of substantially the same or similar configurations as those of the foregoing embodiment are omitted. Hereinafter, the description will be centered on the differences from the foregoing embodiment.

[0085] Referring to FIG. 10, as described above, the plasma treatment apparatus 205 can form the pattern portion 290 to have different lengths, widths, separation distances, and etching depths according to the design of the preset unit cell.

[0086] Specifically, the pattern portion 290 may include a plurality of patterns having different lengths and widths. Here, the plurality of patterns may be formed to have different recess depths.

[0087] As described above, the plasma processing apparatus 200 according to an embodiment of the present invention forms a constant step in a mosaic shape on the surfaces of the discharge rollers 220 and 230, and performs plasma processing with a uniform distribution over the entire longitudinal and width directions of the separation membranes S1 and S2, thereby realizing corona processing of a uniform mosaic pattern and significantly enhancing the adhesiveness, electrolyte impregnation property, and gas exhaust property of a unit cell which is a basic unit.

[0088] In addition, since the plasma processing apparatus 200 according to an embodiment of the present invention can significantly improve the gas exhaust property as described above, it can effectively prevent the lithium plating phenomenon.

[0089] Referring to FIG. 5, the upper electrode supply roller 320 is for supplying the upper electrode E2 in the form of a long fabric, and can supply the upper electrode E2 onto the separation membranes S1 and S2 on which the plasma processing has been performed.

[0090] The lower electrode supply roller 330 is for supplying the lower electrode E3 in the form of a long fabric, is disposed opposite to the upper electrode supply roller 320, and can supply the lower electrode E3 onto the separation membranes S1 and S2 on which the plasma processing has been performed.

[0091] The heater unit 400 is for guiding the adhesion between the separation membranes S1 and S2, the upper electrode E2, and the lower electrode E3, and can apply heat to and heat the upper electrode E2 and the lower electrode E3 placed on the separation membranes S1 and S2.

[0092] The laminating roller 500 can apply pressure onto the upper electrode E2 and the lower electrode E3 adhered to the separation membranes S1 and S2 heated by the heater unit 400 to crimp each electrode and the separation membrane.

[0093] The cutter units 610, 620, 630, and 640 can perform predetermined cutting on each of the supplied central electrode E1, upper electrode E2, lower electrode E3, and separation membranes S1, S2 in the form of a fabric.

[0094] Such cutter units 610, 620, 630, and 640 may include a first cutter 610, a second cutter 620, a third cutter 630, and a fourth cutter 640.

[0095] The first cutter 610 can cut the central electrode E1 into a predetermined size. The second cutter 620 can cut at least one of the upper electrode E2 and the separation membrane S1, and the third cutter 630 can cut at least one of the lower electrode E3 and the separation membrane S2. And the fourth cutter 640 can cut the electrodes E1, E2, E3 and the separation membranes S1, S2 respectively so as to manufacture a unit cell for a secondary battery which is a basic unit.

[0096] Also, although not shown, the manufacturing process of the unit cell for the secondary battery may further include a step of inspecting and discharging the completed unit cell for the secondary battery after the lamination is completed.

[0097] Here, the inspection of the unit cell means an inspection for the presence or absence of foreign matter between the electrode and the separation membrane, whether the unit cell is made in an accurate size, etc. in the lamination process for manufacturing the unit cell.

[0098] As described above, the unit cell for the secondary battery manufactured by the plasma processing apparatuses 200, 205 according to the present embodiment may have an adhesive force that is not uniformly formed and is patterned at the interface between the positive electrode 1 and the separation membrane 3 and / or at the interface between the negative electrode 2 and the separation membrane 3. That is, the interfaces between the electrodes 1, 2 and the separation membrane 3 may have different adhesive forces for different regions, so that the degree of adhesion between the electrodes 1, 2 and the separation membrane 3 may be provided differently for different regions.

[0099] Hereinafter, with reference to the following drawings, the results of the adhesion force measurement test by the plasma processing apparatus according to an embodiment of the present invention will be described.

[0100] FIG. 11 is a diagram for explaining the adhesion force measurement test by the plasma processing apparatus according to an embodiment of the present invention, and FIGS. 12 to 15 are diagrams for explaining the results of the adhesion force measurement test in FIG. 11.

[0101] Referring to FIGS. 11 to 15, first, Reference (indicated as Ref. in FIGS. 12 and 15) is corona treatment of the entire area, and Test #2 and Test #3 mean mosaic corona treatment. FIG. 11 shows the measurement of the facing adhesion force of the folding negative electrode with respect to the products of Test #2 and Test #3. The measurement positions of the adhesion force are positions 1 to 5 in the drawing, the tab part side is position 1, the central part is positions 2 to 4, and the lower end part side is position 5. Also, in FIG. 11, the corona treatment area, that is, the mosaic corona treatment area, is shown in the form of a rectangular box. The bi-cell numbers 2, 3, 6, 7, 10, 11 shown in FIG. 15 are numbers for different positions in the cell due to bi-cell lamination.

[0102] In FIG. 11, in the case of Test #2, mosaic corona treatment was performed in a total of 2 areas on the tab part side (position 1) and the lower end part side (position 5). In the case of Test #3, mosaic corona treatment was performed in a total of 6 areas on the tab part side (position 1), the lower end part side (position 5), the central part (positions 2 and 4), between the central part (position 2) and the tab part side (position 1), and between the central part (position 4) and the lower end part side (position 5).

[0103] As shown in FIGS. 12 to 15, it can be seen that the adhesion force of the folding separation film to the negative electrode in the non-mosaic corona treatment area of the products of Test #2 and Test #3 is low at about 5 gf level. It can be seen that the adhesion force improves in Test #3 when there is a mosaic corona treatment area at positions 2 and 4, that is, in the central part (positions 2 and 4). It can be seen that the adhesion force improves from about 5 gf to 16 gf.

[0104] From the various embodiments of the present invention as described above, by making the adhesive force between the electrodes and the separator of the unit cell used in the production of the secondary battery partially weak or by providing areas where they are not adhered, it is possible to provide plasma treatment apparatuses 200 and 205 that can improve the wettability of the electrolytic solution, and a laminate system 10 for a secondary battery including the same.

[0105] Also, from the various embodiments of the present invention as described above, by guiding the smooth discharge of gas from the unit cell, it is possible to provide plasma treatment apparatuses 200 and 205 that can minimize the lithium plating phenomenon, and a laminate system 10 for a secondary battery including the same.

[0106] As described above, the present invention has been described with reference to limited embodiments and drawings. However, the present invention is not limited thereto, and it goes without saying that various modifications and variations are possible within the equivalent scope of the technical idea and claims of the present invention by those having ordinary knowledge in the technical field to which the present invention pertains.

[0107] In addition, in this specification, terms indicating directions such as up, down, left, right, front, and back are used, but such terms are for convenience of explanation only, and it is obvious to those skilled in the art that they can change depending on the position of the object and the position of the observer, etc.

Explanation of Reference Numerals

[0108] 1 Positive electrode, electrode 1a Positive electrode current collector 1b Positive electrode active material 2 Negative electrode, electrode 2a Negative electrode current collector 2b Negative electrode active material 3 Separator 10 Laminate system for secondary battery 100 Central electrode supply roller 200 Plasma treatment apparatus 205 Plasma treatment apparatus 220 First discharge roller 221 Surface 230 Second discharge roller 240 Metal component 250 Pattern part 252 Contact part 254 Non-contact part 256 Connection part 260 Plasma processing member 261 Processing member main body 263 Insertion groove 264 Electrode piece 265 Switch 290 Pattern part 320 Upper electrode supply roller 330 Lower electrode supply roller 400 Heater unit 500 Laminating roller 610 First cutter 620 Second cutter 630 Third cutter 640 Fourth cutter

Claims

1. A plasma processing apparatus for a unit cell of a secondary battery, comprising: a discharge roller that transfers a separator of the unit cell of the secondary battery and houses a metal member; a plasma processing member that generates plasma by mutual reaction with the metal member and irradiates the surface of the separator; The plasma processing apparatus, wherein a pattern portion is formed on an outer surface of the discharge roller so as to have a predetermined step.

2. The pattern portion includes: a contact portion that is in close contact with the separator when the separator is transferred; The plasma processing apparatus according to claim 1, further comprising: a non-contact portion having a step of a predetermined depth from the contact portion and being separated from the separator by a predetermined distance.

3. When the plasma of the plasma processing member is irradiated, an adhesion region is formed on a surface of the separator disposed on the contact portion side, and a non-adhesion region is formed on a surface of the separator disposed on the non-contact portion side. The plasma processing apparatus according to claim 2.

4. The plasma processing apparatus according to claim 2, wherein the pattern portion includes a connecting portion that connects the contact portion and the non-contact portion.

5. The plasma processing apparatus according to claim 2, wherein the contact portion and the non-contact portion are alternately arranged on an outer surface of the discharge roller.

6. The plasma processing apparatus according to claim 2, wherein the contact portion and the non-contact portion are provided in at least one of a longitudinal direction and a width direction of the discharge roller.

7. The plasma processing apparatus according to claim 2, wherein the non-contact portion is formed to be recessed from an outer surface of the discharge roller by a predetermined depth.

8. The plasma processing apparatus according to claim 7, wherein a depth of a recess of the non-contact portion is 2 mm.

9. The plasma processing apparatus according to any one of claims 1 to 8, wherein the pattern portion includes a plurality of patterns having different lengths or widths.

10. The plasma processing apparatus according to claim 9, wherein the plurality of patterns have different recess depths.

11. The plasma processing apparatus according to claim 1, wherein the pattern portion is provided in a mosaic shape.

12. A laminate system for a secondary battery, comprising the plasma processing apparatus according to claim 1.

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