Separation membrane cutting device

Abstract

The disclosed invention relates to a separation membrane cutting device in a lamination process for stacking electrode assemblies, the separation membrane cutting device including a fixing part for temporarily fixing the electrode assembly being transferred, a cutter support part disposed above the fixing part, a cutter part disposed below the cutter support part for cutting a separation membrane in the electrode assembly temporarily fixed to the fixing part, and a spring part for elastically connecting the cutter support part and the cutter part to each other and returning the cutter part to its initial position after cutting the separation membrane. The spring part includes a spring bush connected to a support shaft provided on the cutter support part and the cutter part, respectively, a spring holder integrally connected to the spring bush, and a spring having both ends connected to the spring holder and expanding and contracting in response to the elevation and lowering of the cutter part, the spring holder and the spring bush being made of non-metallic material.

Description

[Technical field]

[0001] This application claims the benefit of priority based on Korean Patent Application No. 10-2021-0153806 dated November 10, 2021, and all contents disclosed in the documents of that Korean patent application are incorporated herein by reference.

[0002] The present invention relates to a separation membrane cutting device.

[0003] More particularly, the present invention relates to a separation film cutting device that can reduce friction with surrounding metals by improving the structure of a spring part that elastically returns a cutter that has cut a separation film in a lamination process.

[0004] The present invention also relates to a separation membrane cutting device in which the spring part is improved to be made of a non-metallic material, thereby preventing the generation of foreign matter due to friction with surrounding metals. [Background technology]

[0005] 2. Description of the Related Art In recent years, secondary batteries that are capable of being charged and discharged have come to be widely used as energy sources for wireless mobile devices.

[0006] In addition, secondary batteries are attracting attention not only for portable devices such as mobile phones, notebook computers, and camcorders, but also as energy sources for electric vehicles and hybrid electric vehicles, which have been proposed as a solution to air pollution caused by existing gasoline-powered and diesel-powered vehicles that use fossil fuels.

[0007] Therefore, the types of applications using secondary batteries are becoming increasingly diverse due to the advantages of secondary batteries, and it is expected that secondary batteries will be applied to more fields and products in the future.

[0008] Such secondary batteries are classified into lithium ion batteries, lithium ion polymer batteries, lithium polymer batteries, etc. depending on the configuration of the electrodes and electrolyte. The use of lithium ion polymer batteries, which are less likely to leak electrolyte and are easy to manufacture, is increasing.

[0009] Generally, secondary batteries are classified according to the shape of the battery case into cylindrical batteries and prismatic batteries in which the electrode assembly is housed in a cylindrical or prismatic metal can, and pouch batteries in which the electrode assembly is housed in a pouch-type case made of an aluminum lamination sheet.

[0010] The electrode assembly built into the battery case is a power generating element capable of charging and discharging, which is composed of a positive electrode, a negative electrode, and a separator interposed between the positive and negative electrodes. It is classified into a jelly roll type in which a separator is interposed between long sheet-like positive and negative electrodes coated with an active material and then wound up, and a stack type in which a number of positive and negative electrodes formed to a predetermined size are stacked in sequence with a separator interposed between them.

[0011] Here, electric vehicles and the like require a large number of battery modules since they use high-output electric energy, and such battery modules have a large number of battery cells connected in series or parallel inside.

[0012] Such a battery cell is manufactured through a notching process of notching the electrodes, a lamination process of laminating the notched electrodes, a separator cutting process of cutting a separator from the laminated electrode assembly, a stacking process, a crimping process, a packaging process, and a degassing process.

[0013] As shown in FIG. 1, the positive electrode and the negative electrode are supplied via a positive electrode supply roll 201 and a negative electrode supply roll 203, and at this time, the positive electrode and the negative electrode are supplied while being separated via respective cutting devices 201a and 203a.

[0014] A separator supplied through a separator supply roll 205 is interposed between the positive electrode and the negative electrode, and the positive electrode, the negative electrode and the separator are laminated through a lamination device 200. The separator is cut from the laminated electrode assembly 101 through a separator cutting device 100 provided at the rear end of the lamination device 200.

[0015] The separation membrane cutting device 100, as shown in FIG. 2, includes a fixing part (not shown) to which an electrode assembly is fixed, a cutter support part 103, a cutter part 105 that cuts the separation membrane, and a spring part 107 that returns the cutter part after cutting the separation membrane to its initial position.

[0016] Here, the spring part 107 is structured such that both ends are connected to the cutter support part 103 and the cutter part 105, and the cutter part 105, which has cut the separation film on the fixed part, is returned to its original position by the elasticity of the spring part 107.

[0017] As described above, after the spring part cuts the separation film on the fixed part, vibration is generated when the cutter part returns to the initial position, and friction occurs when the spring part comes into contact with the metal structure including the frame.

[0018] In this case, since the spring part is made of SUS material, it can be crushed or sharpened when it comes into contact with metal structures including the frame, causing problems such as foreign matter flowing into the electrode assembly and causing short circuits and low voltage failures.

[0019] Therefore, there is a need for an improved spring structure that can minimize the generation of foreign matter through a spring that returns the cutter to its initial position after cutting the separation membrane on the fixed part, thereby improving product quality. [Prior art documents] [Patent documents]

[0020] [Patent Document 1] Korean Patent No. 10-1791297 Summary of the Invention [Problem to be solved by the invention]

[0021] The present invention has been made to solve the above-mentioned problems, and aims to provide a separation membrane cutting device that can reduce friction with surrounding metals by improving the structure of a spring part that elastically returns a cutter that cuts a separation membrane during a lamination process.

[0022] Another object of the present invention is to provide a separation membrane cutting device that can prevent the generation of foreign matter due to friction with surrounding metals by improving the spring part to a non-metallic material. [Means for solving the problem]

[0023] In order to achieve the above object, the present invention provides a separation membrane cutting device in a lamination process for stacking electrode assemblies, the device including: a fixing part for temporarily fixing the electrode assembly being transferred; a cutter support part disposed above the fixing part; a cutter part disposed below the cutter support part for cutting a separation membrane in the electrode assembly temporarily fixed to the fixing part; and a spring part for elastically connecting the cutter support part and the cutter part to each other and returning the cutter part to its initial position after cutting the separation membrane, the spring part including a spring bushing connected to a support shaft provided on the cutter support part and the cutter part, respectively; a spring holder integrally connected to the spring bushing; and a spring having both ends attached to the spring holder and expanding and contracting in response to the elevation and lowering of the cutter part, the spring holder and the spring bushing being made of a non-metallic material.

[0024] In one example, the spring holder and the spring bushing are integrally formed.

[0025] As another example, the spring holder and spring bushing are an engineering plastic.

[0026] As a specific example, the spring holder and spring bushing comprise polyetheretherketone (PEEK).

[0027] In one example, the spring holder is a helical holder of the helical coil type.

[0028] In a specific example, both ends of the spring are threaded directly into a helical holder of the helical type.

[0029] As another example, the spring holder is a hollow cylindrical member that is integrally formed and connected with the spring bush, and the end of the spring is closely fixed to the inner surface of the hollow cylindrical spring holder.

[0030] In one embodiment, the spring holder is hollow and cylindrical, and has an inner surface formed with threads that correspond to the spirals of the spring.

[0031] In another embodiment, the ends of the springs are threaded directly onto the threads.

[0032] As another example, the spring holder is a hollow cylindrical member integrally connected to the spring bushing, and a cylindrical protrusion is provided at the center of the hollow cylindrical spring holder. The end of the spring is inserted into an annular coupling groove formed in the internal space of the hollow cylindrical spring holder by the protrusion, and is fixed under pressure.

[0033] As a specific example, the annular coupling groove has two opposing inner surfaces each formed with a screw thread corresponding to the spiral of the spring.

[0034] Another embodiment is a double threaded connection of the ends of the spring directly onto the threads. Effect of the Invention

[0035] According to the present invention, the structure of the spring part of the separation membrane cutting device is improved to suppress friction with surrounding metals, and the spring part is made of a non-metallic material to prevent the generation of foreign matter due to friction with surrounding metals.

[0036] Therefore, the present invention can prevent short circuit defects and low voltage defects caused by foreign substances entering the electrode assembly, and can improve product quality by minimizing the generation of foreign substances through the spring portion. [Brief description of the drawings]

[0037] [Figure 1] 4 is a process diagram illustrating a lamination process and a separator cutting process in a battery cell manufacturing process. FIG. [Diagram 2] 1 is a schematic view of a spring part of a separation membrane cutting device according to the prior art. [Diagram 3] 1 is a schematic view of a separation membrane cutting device according to the present invention. [Figure 4] 2 is a perspective view showing a spring part according to an embodiment of the separation membrane cutting device according to the present invention; FIG. [Diagram 5] FIG. 4 is an exploded front view of the spring portion according to the embodiment. [Figure 6] 1 is a schematic view illustrating a state in which a spring unit according to an embodiment of the present invention is applied to a separation membrane cutting device. [Figure 7] FIG. 11 is an exploded front view showing a spring part according to another embodiment of the separation membrane cutting device according to the present invention. [Figure 8] 4 is a front cross-sectional view that shows a schematic view of a spring bush and a spring holder of the spring portion according to the present embodiment. FIG. [Figure 9] 4 is a front cross-sectional view illustrating a state in which a spring is coupled to a spring holder of a spring portion according to the present embodiment; FIG. [Figure 10] 1 is a schematic view illustrating a state in which a spring unit according to an embodiment of the present invention is applied to a separation membrane cutting device. [Figure 11] 11 is a front cross-sectional view illustrating a spring bush and a spring holder of a spring part according to another embodiment of a separation membrane cutting device according to the present invention. FIG. [Figure 12] 4 is a front cross-sectional view illustrating a state in which a spring is coupled to a spring holder of a spring portion according to the present embodiment; FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0038] The present invention provides a separation membrane cutting device used in a lamination process for stacking electrode assemblies, the separation membrane cutting device comprising: a fixing part for temporarily fixing the electrode assembly being transported; a cutter support part disposed above the fixing part; a cutter part disposed below the cutter support part for cutting a separation membrane in the electrode assembly temporarily fixed to the fixing part; and a spring part for elastically connecting the cutter support part and the cutter part to each other and returning the cutter part to its initial position after cutting the separation membrane, the spring part comprising: a spring bushing connected to a support shaft provided on the cutter support part and the cutter part, respectively; a spring holder integrally connected to the spring bushing; and a spring whose both ends are bound to the spring holder and which expands and contracts in response to the elevation and lowering of the cutter part, the spring holder and the spring bushing being made of a non-metallic material.

[0039] The present invention will be described in detail below. Before that, the terms and words used in the specification and claims should not be interpreted as being limited to their ordinary or dictionary meanings, but should be interpreted as meanings and concepts that correspond to the technical ideas of the present invention based on the principle that the inventor can appropriately define the concepts of terms in order to best describe his own invention.

[0040] As used throughout the present specification, terms such as "comprise" and "have" are intended to specify the presence of any feature, numeral, step, operation, component, part, or combination thereof described in the specification, but should be understood as not precluding the presence or additional possibility of one or more other features, numerals, steps, operations, components, parts, or combinations thereof.

[0041] Furthermore, when a layer, film, region, plate, or other part is described as being "on" another part, this includes not only the case where it is "directly on" the other part, but also the case where there is another part in between. Conversely, when a layer, film, region, plate, or other part is described as being "under" another part, this includes not only the case where it is "directly under" the other part, but also the case where there is another part in between. Furthermore, in the specification of the present invention, being disposed "on" can include not only the case where it is disposed on the upper side, but also the case where it is disposed on the lower side.

[0042] (First embodiment) Fig. 3 is a schematic diagram of a separation membrane cutting device according to the present invention. Fig. 4 is a schematic perspective view of a spring unit according to an embodiment of the separation membrane cutting device according to the present invention. Fig. 5 is an exploded front view of the spring unit according to the present embodiment. Fig. 6 is a schematic diagram of the spring unit according to the present embodiment applied to a separation membrane cutting device.

[0043] As shown in FIG. 3, the separation membrane cutting device 1 according to the present invention includes a fixed part 10 to which an electrode assembly 3 is transported, a cutter support part 20 arranged above the fixed part 10, a cutter part 30 arranged below the cutter support part 20 to cut the separation membrane 3b, and a spring part 40 to return the cutter part 30 having cut the separation membrane 3b to its initial position.

[0044] The fixing unit 10 is for temporarily fixing the electrode assembly 3 being transported, and is a section where the separator 3b is cut from the electrode assembly 3 in which the positive electrode 3a, the negative electrode 3c, and the separator 3b are stacked.

[0045] The cutter support part 20 is disposed above the fixed part 10 and supports a cutter part 30 which cuts the separation membrane 3b.

[0046] The cutter unit 30 is disposed below the cutter support unit 20 and is vertically movable to cut the separator 3b in the electrode assembly 3 transferred to the upper surface of the fixing unit 10.

[0047] The spring portion 40 elastically connects the upper cutter support portion 20 and the cutter portion 30 to each other, and returns the cutter portion 30 to its initial position after cutting the separation membrane 3b.

[0048] To this end, the cutter support part 20 and the cutter part 30 are provided with support shafts 21 and 31, respectively, and both ends of a spring 48 are coupled to the support shafts 21 and 31 to return the cutter part 30 to its initial position after cutting the separation membrane 3b.

[0049] Meanwhile, as shown in FIG. 4 and FIG. 5, the spring part 40 includes a spring bush 41 connected to the support shafts 21, 31 provided in the cutter support part 20 and the cutter part 30, respectively, a spring holder 43 connected integrally to the spring bush 41, and a coil-shaped spring 48 whose both ends are bound to the spring holder 43 and which expands and contracts according to the elevation and lowering of the cutter part 30.

[0050] The spring bush 41 is in the form of a bar, and has a connecting hole 41a formed therethrough so as to be connected to the support shafts 21 and 31 provided on the cutter support part 20 and the cutter part 30, respectively.

[0051] The spring holder 43 is coupled to an end of the spring bush 41 and is a heli-coil type spiral holder.

[0052] The spring 48 is connected at both ends to the spring holder 43, and is extended when the cutter unit 30 cuts the separation membrane 3b on the fixed unit 10, and is elastically contracted after the separation membrane 3b is cut, thereby returning the cutter unit 30 to its initial position.

[0053] As described above, both ends of the spring 48 are connected to the spring holders 43, and the spring holders 43 are attached to the support shafts 21, 31 of the cutter support part 20 and the cutter part 30 by the spring bushings 41, thereby minimizing vibration of the cutter part 30 returning to its initial position after cutting the separation film 3b and minimizing friction caused by contact between the springs 48 and the peripheral metal structures provided around the cutter part 30.

[0054] Meanwhile, both ends of the spring 48 are directly screwed to the helicoil type spring holder 43. That is, the spirally twisted spring wire forming the spring 48 is screwed while rotating along the continuous spiral space of the helicoil type spring holder 43.

[0055] For this, the spiral direction of the spring 48 and the spiral direction of the spring holder 43 are formed to be the same, and the spring wires at both ends of the spring 48 are screwed into the spiral space of the spring holder 48 and fixed on both sides.

[0056] Here, the spring holder 43 and the spring bush 41 are made of a non-metallic material. Since the spring holder 43 and the spring bush 41 are made of a non-metallic material, it is possible to prevent the generation of metallic foreign matter when the cutter part 30 comes into contact with a metallic structure provided around the cutter part 30.

[0057] At this time, it is preferable that the spring holder 43 and the spring bush 41 are integrally formed, but the spring holder 43 and the spring bush 41 may be separable, or may be modified in various other ways.

[0058] On the other hand, the spring holder 43 and the spring bush 41 are made of engineering plastic.

[0059] Preferably, the spring holder 43 and the spring bush 41 are made of polyetheretherketone (PEEK).

[0060] In one embodiment of the present invention, the spring holder 43 and the spring bush 41 are made of engineering plastic material or polyetheretherketone (PEEK), but the present invention is not limited thereto and may be modified in various other ways.

[0061] Hereinafter, a process for installing a spring unit in a separation membrane cutting device according to an embodiment of the present invention will be briefly described with reference to FIGS.

[0062] First, the spring holders 43 formed integrally with the spring bush 41 are provided on both ends of the spring 48 .

[0063] At this time, the spring 48 rotates along the continuous spiral space inside the helical spring holder 43, and the spirally twisted spring wire is connected to the spring 48, so that the two are screwed together.

[0064] In this manner, after the spring holders 43 are screwed to both ends of the spring 48, the spring bushes 41 integrally connected to the spring holders 43 are fastened to the support shafts 21, 31 formed on the cutter support part 20 and the cutter part 30, respectively.

[0065] Here, when fastening the spring bush 41 to each support shaft 21, 31 formed on the cutter support part 20 and the cutter part 30, the support shaft 21, 31 is inserted into the connection hole 41a of the spring bush 41, and then the support shaft 21, 31 is fixed by fastening a fastening member (not shown) such as a nut.

[0066] Hereinafter, an operation process of the separation membrane cutting device according to an embodiment of the present invention will be briefly described with reference to FIG.

[0067] First, the electrode assembly 3 laminated through the lamination device is transferred to the upper surface of the fixing part 10 of the separator cutting device 1 .

[0068] The separation membrane cutting device 1 cuts the separation membrane 3b from the electrode assembly 3 in which a positive electrode 3a, a separation membrane 3b, and a negative electrode 3c are stacked.

[0069] That is, when the electrode assembly 3 is transferred onto the fixed part 10, the cutter unit 30 provided on the lower side of the cutter support unit 20 descends toward the upper side of the fixed part 10 by a hydraulic or electrical signal, and the cutting knife 33 of the cutter unit 30 comes into contact with the upper side of the fixed part 10 to cut the separation membrane 3b of the electrode assembly 3.

[0070] Here, a spring 48, both ends of which are bound within a spring holder 43 integrally connected to the spring bushing 41, is stretched, causing the cutter unit 30 to descend toward the upper surface of the fixed unit 10, and after cutting the separation membrane 3b, the spring 48 is contracted, returning the cutter unit 30 to its initial position.

[0071] At this time, both ends of the spring 48 screwed into the spring holder 43 are not expanded or contracted when the cutter unit 30 is driven, and the remaining part of the spring 48 disposed outside the spring holder 43 is expanded or contracted when the cutter unit 30 is driven.

[0072] Therefore, by screwing both ends of the spring 48 into the spring holder 43, the elastic range of the spring 48 can be limited due to repeated driving and vibration of the cutter unit 30, and contact between the spring 48 and surrounding metal structures can be minimized.

[0073] In addition, since both ends of the spring 48 made of a metallic material are screwed into each spring holder 43 made of a non-metallic material, the spring 48 does not come into direct contact with the surrounding metallic structures due to the spring holder 43 coming into contact with the surrounding metallic structures due to repeated driving and vibration of the cutter part 30, and therefore the generation of metallic foreign matter due to friction between metals can be eliminated.

[0074] Second embodiment Fig. 7 is an exploded front view of a spring unit according to another embodiment of a separation membrane cutting device according to the present invention. Fig. 8 is a front sectional view showing a spring bush and a spring holder of the spring unit according to the present embodiment. Fig. 9 is a front sectional view showing a state in which a spring is coupled to a spring holder of the spring unit according to the present embodiment. Fig. 10 is a view showing a state in which the spring unit according to the present embodiment is applied to a separation membrane cutting device.

[0075] As shown in Figures 7 to 10, the spring part 40' according to this embodiment is a hollow cylindrical member in which a spring holder 43' is integrally connected with a spring bush 41, and the end of the spring is tightly fixed to the inner surface of the hollow cylindrical spring holder 43'.

[0076] That is, the spring holder 43' of the spring part 40' according to this embodiment is formed integrally with the spring bush 41 and is a cylindrical member having a hollow inside, and the end of the spring 48 is inserted into the hollow inner surface of the spring holder 43' and fixed in close contact therewith.

[0077] For this purpose, a screw thread 44a corresponding to the spiral of the spring 48 is formed on the inner surface of the hollow cylindrical spring holder 43', and the spiral direction of the spring 48 and the screw direction formed on the spring holder 43' are formed to be the same.

[0078] With the above-mentioned configuration, when both ends of the spring 48 are connected to the hollow of the spring holder 43', both ends of the spring 48 are directly screwed and fixed to the screw threads 44a formed on the inner surface of the hollow of the spring holder 43'.

[0079] Third embodiment Fig. 11 is a front cross-sectional view showing a spring bush and a spring holder of a spring part according to another embodiment of a separation membrane cutting device according to the present invention, and Fig. 12 is a front cross-sectional view showing a state in which a spring is coupled to a spring holder of the spring part according to the present embodiment.

[0080] As shown in FIG. 11, the spring part 40″ according to the present embodiment is a hollow cylindrical member in which a spring holder 43″ is integrally connected with the spring bush 41, and a cylindrical protrusion 45 is provided at the center of the hollow cylindrical spring holder 43″. An end of the spring 48 is inserted into an annular coupling groove 46 formed in the internal space of the cylindrical spring holder 43″ by the protrusion 45, and is fixed under pressure.

[0081] That is, the spring holder 43'' according to this embodiment is a cylindrical member having a hollow inside, and is integrally formed and connected with the spring bush 41, and a cylindrical protrusion 45 is protruded from the center of the hollow of the spring holder 43''.

[0082] The protrusion 45 forms an annular coupling groove 46 in the internal space between the peripheral surface of the protrusion 45 and the hollow inner surface facing the peripheral surface, and an end of a spring 48 is inserted into the annular coupling groove 46 and fixed therein by application of pressure.

[0083] Meanwhile, two opposing inner surfaces formed by the annular coupling groove 46 are formed with threads 44b corresponding to the spiral of the spring 48. That is, the threads 44b are formed on the circumferential surface of the protruding portion 45 of the spring holder 43'', and the threads 44b are formed on the hollow inner surface of the spring holder 43'' opposing the circumferential surface of the protruding portion 45.

[0084] In this case, the helical direction of the threads 44b formed in the annular coupling groove 46 formed in the spring holder 43'' and the helical direction of the spring 48 are formed to be the same.

[0085] With the above-described construction, the ends of the spring 48 are directly and double-threadedly coupled to the threads 44b formed in the annular coupling groove 46, as shown in FIG.

[0086] As a modified example, a screw thread 44b corresponding to the spiral of the spring 48 may be formed on the circumferential surface of the protrusion 45 among two mutually opposing inner surfaces forming the annular coupling groove 46 of the spring holder 43'', and an end of the spring 48 may be screwed into the coupling groove 46.

[0087] As another modified example, a screw thread 44b corresponding to the spiral of the spring 48 may be formed on a hollow inner surface of two mutually opposing inner surfaces forming the annular coupling groove 46 of the spring holder 43'', and an end of the spring 48 may be screwed into the coupling groove 46.

[0088] While the present invention has been illustrated and described with reference to specific embodiments, it will be readily apparent to anyone skilled in the art that various modifications and variations can be made therein without departing from the spirit and scope of the invention as set forth in the appended claims. [Explanation of symbols]

[0089] 1: Separation membrane cutting device 3: Electrode assembly 3a: Positive electrode 3b: Separation membrane 3c: negative electrode 10: Fixed part 20: Cutter support part 21: Support shaft 30: Cutter section 31: Support shaft 33: Cutting knife 40, 40', 40": Spring section 41: Spring bush 41a: Bonding hole 43, 43', 43”: Spring holder 44a, 44b: Thread 45:Protrusion 46:Join groove 48: Spring

Claims

1. A separator cutting device in a lamination process for stacking electrode assemblies, a fixing part for temporarily fixing the electrode assembly on an upper surface of the electrode assembly to be transferred; A cutter support portion disposed above the fixed portion; a cutter unit disposed under the cutter support unit and configured to cut a separator in the electrode assembly temporarily fixed to the fixing unit; a spring portion that elastically connects the cutter support portion and the cutter portion to each other and returns the cutter portion to its initial position after cutting the separation film, the spring portion includes a spring bushing coupled to a support shaft provided on the cutter support portion and the cutter portion, respectively, a spring holder integrally coupled to the spring bushing, and a spring having both ends bound within the spring holder and expanding and contracting in response to elevation and lowering of the cutter portion, the spring holder and the spring bushing comprise a non-metallic material; the ends of the spring in the spring holder are threadedly connected; the cutter portion and the cutter support portion are located on the upper surface of the fixed portion, the spring is expanded, and the cutter portion moves down toward the upper surface of the fixing portion to come into contact with the upper surface of the fixing portion and cut the separator of the electrode assembly.

2. The separation membrane cutting device according to claim 1 , wherein the spring holder and the spring bush are integrally formed.

3. The separation membrane cutting device according to claim 1 , wherein the spring holder and the spring bush are made of engineering plastic.

4. The separation membrane cutting device according to claim 3 , wherein the spring holder and the spring bushing comprise polyetheretherketone (PEEK).

5. The separation membrane cutting device according to claim 1 , wherein the spring holder is a coil-type spiral holder.

6. The separation membrane cutting device according to claim 5 , wherein both ends of the spring are directly screwed to the coil-type spiral holder.

7. The separation membrane cutting device according to any one of claims 1 to 6, wherein the spring holder is a hollow cylindrical member integrally formed and connected with the spring bush, and an end of the spring is closely attached and fixed to an inner surface of the hollow cylindrical spring holder.

8. The separation membrane cutting device according to claim 7, wherein the hollow cylindrical spring holder has an inner surface formed with a screw thread corresponding to the spiral of the spring.

9. The separation membrane cutting device according to claim 8 , wherein an end of the spring is directly screw-coupled to the screw thread.

10. The spring holder is a hollow cylindrical member integrally formed and connected with the spring bush, and a cylindrical protrusion is provided at the center of the hollow cylindrical spring holder, 7. The separation membrane cutting device according to claim 1, wherein an end of the spring is inserted into an annular coupling groove formed in an internal space of the hollow cylindrical spring holder by the protrusion and is pressurized and fixed.

11. The separation membrane cutting device according to claim 10, wherein the annular coupling groove has two opposing inner surfaces each having a thread corresponding to a spiral of the spring.

12. A separation membrane cutting device as described in claim 11, wherein the ends of the spring are threadedly engaged with two adjacent threads.

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