Separator winding roll, method for manufacturing separator winding roll, device for manufacturing electrode assembly, and method for manufacturing electrode assembly

Abstract

An electrode assembly manufacturing apparatus includes: a separator winding roll in which two or more layers of separators are stacked and wound; a diaphragm supply unit for individually separating and supplying the two or more layers of diaphragms from the diaphragm winding roll; a first electrode supply unit for supplying a first electrode; a second electrode supply unit for supplying a second electrode; and a winding unit for stacking and winding individually separated separators between the first electrode and the second electrode and on one outer side of the first electrode or the second electrode.

Description

[0001] Cross-references to related applications

[0002] This application is based on and claims priority to Korean Patent Application No. 10-2023-0193317, filed with the Korean Intellectual Property Office on December 27, 2023, the disclosure of which is incorporated herein by reference in its entirety. Technical Field

[0003] This disclosure relates to a wound diaphragm, a method for manufacturing a wound diaphragm, an apparatus for manufacturing an electrode assembly, and a method for manufacturing an electrode assembly. Background Technology

[0004] With the development and increasing demand for mobile device technology, the demand for secondary batteries as an energy source is rapidly increasing. For example, secondary batteries are attracting attention not only as an energy source for mobile devices such as mobile phones, digital cameras, laptops, and wearable devices, but also as an energy source for power devices such as electric bicycles, electric vehicles (EVs), and hybrid electric vehicles (HEVs).

[0005] Based on the shape of the battery casing, secondary batteries are classified as follows: cylindrical batteries, in which the electrode assembly is built into a cylindrical metal can; prismatic batteries, in which the electrode assembly is built into a square metal can; and pouch batteries, in which the electrode assembly is built into a pouch-shaped casing made of aluminum laminate. Among these secondary batteries, cylindrical batteries have the advantages of relatively large capacity and structural stability compared to other types of batteries. Summary of the Invention

[0006] Technical issues

[0007] This disclosure provides a novel diaphragm in which two or more diaphragms are stacked and wound together.

[0008] This disclosure provides a method for manufacturing a diaphragm in which two or more diaphragm layers are stacked and wound together.

[0009] This disclosure provides an electrode assembly manufacturing apparatus that includes a diaphragm supply unit by using a novel wound diaphragm (in which two or more diaphragms are stacked and wound), and has a simplified process structure.

[0010] This disclosure provides a method for manufacturing an electrode assembly, which includes a diaphragm supply unit by using a novel wound diaphragm (in which two or more diaphragms are stacked and wound), and has a simplified process structure.

[0011] Technical solution

[0012] According to one aspect of this disclosure, a winding diaphragm, an electrode assembly manufacturing apparatus, and an electrode assembly manufacturing method are provided according to the following embodiments.

[0013] According to the first embodiment, the wound diaphragm comprises two or more layers of diaphragms stacked and wound together.

[0014] According to the second embodiment, in the first embodiment, the two or more diaphragms may include a first diaphragm and a second diaphragm, and the winding length of the second diaphragm may be longer than the winding length of the first diaphragm.

[0015] According to the third embodiment, in the first or second embodiment, the two or more diaphragms may include a first diaphragm and a second diaphragm, and one end of the winding end of the first diaphragm and the second diaphragm may be wound in such a way that it wraps around the remaining end, such that the one end is unwound before the remaining end during unwinding.

[0016] According to the fourth embodiment, in any one of the first to third embodiments, the two or more diaphragms may include a first diaphragm and a second diaphragm. The first diaphragm may include a first porous polymer substrate and a first inorganic heat-resistant layer on at least one surface of the first porous polymer substrate. The first inorganic heat-resistant layer includes first inorganic particles and a first adhesive polymer. The second diaphragm may include a second porous polymer substrate and a second inorganic heat-resistant layer on at least one surface of the second porous polymer substrate. The second inorganic heat-resistant layer includes second inorganic particles and a second adhesive polymer.

[0017] According to the fifth embodiment, in the fourth embodiment, the wound diaphragm may further include an intermediate layer film on at least one of the first inorganic heat-resistant layer and the second inorganic heat-resistant layer.

[0018] According to a sixth embodiment, a method for manufacturing a wound diaphragm is provided, comprising: introducing a first mixture comprising a first diluent and a first polymer resin into an extruder, subsequently extruding and cooling to obtain a first unstretched sheet; introducing a second mixture comprising a second diluent and a second polymer resin into an extruder, subsequently extruding and cooling to obtain a second unstretched sheet; stacking the first unstretched sheet and the second unstretched sheet to obtain an unstretched stacked sheet; performing a first stretch on the unstretched stacked sheet in a first direction to obtain a first stretched stacked sheet; performing a second stretch on the first stretched stacked sheet in a second direction to obtain a second stretched stacked sheet; extracting the first diluent and the second diluent from the second stretched stacked sheet to obtain a stacked diaphragm wherein the first diaphragm and the second diaphragm are stacked; and winding the stacked diaphragm obtained in the extraction.

[0019] According to the seventh embodiment, in the sixth embodiment, the method may further include thermally fixing the stacked diaphragms.

[0020] According to the eighth embodiment, in the sixth or seventh embodiment, the first mixture may further include a first initiator and a first crosslinking agent, the second mixture may further include a second initiator and a second crosslinking agent, and the method may further include crosslinking the stacked membrane obtained by extracting the first diluent and the second diluent.

[0021] According to a ninth embodiment, a method for manufacturing a wound separator is provided, comprising: introducing a third mixture comprising a third diluent and a third polymer resin into an extruder, subsequently extruding and cooling to obtain a third unstretched sheet; introducing a fourth mixture comprising a fourth diluent and a fourth polymer resin into an extruder, subsequently extruding and cooling to obtain a fourth unstretched sheet; subjecting the third unstretched sheet and the fourth unstretched sheet to a first stretch in a first direction to obtain a first-stretched third sheet and a first-stretched fourth sheet; subjecting the first-stretched third sheet and the first-stretched fourth sheet to a second stretch in a second direction to obtain a second-stretched third sheet and a second-stretched fourth sheet; and subjecting the second-stretched third sheet and the fourth unstretched sheet to a second stretch in a second direction to obtain a second-stretched third sheet and a second-stretched fourth sheet; and subjecting the second-stretched third sheet and the fourth unstretched sheet to a second stretch in a second direction to a second stretch in a second direction to obtain a second-stretched third sheet and a second-stretched fourth sheet; and subjecting the second-stretched third sheet and the fourth unstretched fourth sheet to a second stretch in a second direction to a second stretch in a second direction to a second stretch in a second stretch in a second stretch in a third stretch in a second stretch in a fourth stretch in a second stretch in a third ... The third diluent and the fourth diluent are extracted from the fourth sheet after the second stretching to obtain a third porous polymer substrate and a fourth porous polymer substrate; a slurry for forming a third inorganic heat-resistant layer, comprising third inorganic particles and a third binder polymer, is applied to at least one surface of the third porous polymer substrate and dried to form a third inorganic heat-resistant layer; a slurry for forming a fourth inorganic heat-resistant layer, comprising fourth inorganic particles and a fourth binder polymer, is applied to at least one surface of the fourth porous polymer substrate and dried to form a fourth inorganic heat-resistant layer; and the third porous polymer substrate on which the third inorganic heat-resistant layer is formed and the fourth porous polymer substrate on which the fourth inorganic heat-resistant layer is formed are stacked and wound together.

[0022] According to the tenth embodiment, in the ninth embodiment, the method may further include heat-fixing the third porous polymer substrate and the fourth porous polymer substrate obtained by extracting the third diluent and the fourth diluent, respectively.

[0023] According to the eleventh embodiment, in the ninth or tenth embodiment, the third mixture may further include a third initiator and a third crosslinking agent, the fourth mixture may further include a fourth initiator and a fourth crosslinking agent, and the method may further include crosslinking the third porous polymer substrate and the fourth porous polymer substrate obtained by extracting the third diluent and the fourth diluent, respectively.

[0024] According to the twelfth embodiment, in any of the ninth to eleventh embodiments, the stacking and winding may include further stacking an intermediate layer film on at least one of the third inorganic heat-resistant layer and the fourth inorganic heat-resistant layer, followed by winding.

[0025] According to a thirteenth embodiment, an electrode assembly manufacturing apparatus includes: a winding diaphragm, wherein two or more diaphragms are stacked and wound; a diaphragm supply unit that individually separates and supplies the two or more diaphragms from the wound diaphragm; a first electrode supply unit that supplies a first electrode; a second electrode supply unit that supplies a second electrode; and a winding unit that individually stacks and winds the diaphragms separated and supplied by the diaphragm supply unit between the first electrode and the second electrode and on the outside of the first electrode or the second electrode.

[0026] According to the fourteenth embodiment, in the thirteenth embodiment, the two or more layers of diaphragms stacked in the wound diaphragm may include a first diaphragm and a second diaphragm, and the winding length of the second diaphragm may be longer than the winding length of the first diaphragm.

[0027] According to the fifteenth embodiment, in the thirteenth or fourteenth embodiment, the two or more layers of diaphragms stacked in the wound diaphragm may include a first diaphragm and a second diaphragm, and one end of the wound end of the first diaphragm and the second diaphragm may be wound in such a way that it wraps around the remaining end, such that the one end is unwound before the remaining end during unwinding.

[0028] According to the sixteenth embodiment, in any of the thirteenth to fifteenth embodiments, the two or more diaphragms stacked in the wound diaphragm may include a first diaphragm and a second diaphragm, and the winding unit may sequentially stack and wind the first electrode, the first diaphragm, the second electrode and the second diaphragm.

[0029] According to the seventeenth embodiment, in the sixteenth embodiment, the electrode assembly manufacturing apparatus may further include: at least one first guide roller that supplies the first diaphragm supplied by unwinding the wound diaphragm to the gap between the first electrode and the second electrode; and at least one second guide roller that supplies the second diaphragm supplied by unwinding the wound diaphragm in a direction opposite to one surface of the first electrode and the second electrode.

[0030] According to the eighteenth embodiment, in the seventeenth embodiment, the at least one second guide roller may be arranged such that a second diaphragm supply path extending from the diaphragm supply unit to the winding unit bypasses the first electrode supply unit or the second electrode supply unit.

[0031] According to the nineteenth embodiment, in any one of the sixteenth to eighteenth embodiments, the winding length of the second diaphragm may be longer than the winding length of the first diaphragm.

[0032] According to the twentieth embodiment, in any one of the sixteenth to nineteenth embodiments, the winding length of the second diaphragm may be longer than the winding length of the first diaphragm, and the difference between the winding length of the second diaphragm and the winding length of the first diaphragm is equal to or longer than the difference between the length of the second diaphragm supply path extending from the diaphragm supply unit to the winding unit and the length of the first diaphragm supply path extending from the diaphragm supply unit to the winding unit.

[0033] According to the twenty-first embodiment, a method for manufacturing an electrode assembly is provided, comprising: separating two or more diaphragms individually from a wound diaphragm in which two or more diaphragms are stacked and wound; supplying the diaphragms individually separated in the separation; supplying a first electrode; supplying a second electrode; and stacking and winding the diaphragms individually separated in the separation between the first electrode and the second electrode and on the outside of the first electrode or the second electrode.

[0034] According to the twenty-second embodiment, in the twenty-first embodiment, supplying the diaphragm, supplying the first electrode, supplying the second electrode, and stacking and winding the diaphragm can be performed simultaneously after separating the two or more layers of diaphragm.

[0035] According to the twenty-third embodiment, in the twenty-first or twenty-second embodiment, the two or more layers of diaphragms may include a first diaphragm and a second diaphragm, and in stacking and winding the diaphragms, the first electrode, the first diaphragm, the second electrode and the second diaphragm may be stacked and wound in sequence.

[0036] According to the twenty-fourth embodiment, in the twenty-third embodiment, the winding length of the second diaphragm can be longer than the winding length of the first diaphragm.

[0037] According to the twenty-fifth embodiment, in the twenty-third or twenty-fourth embodiment, the separation of the two or more diaphragms can be performed using a diaphragm supply unit, and the stacking and winding of the diaphragms can be performed using a winding unit. The winding length of the second diaphragm can be longer than the winding length of the first diaphragm, and the difference between the winding length of the second diaphragm and the winding length of the first diaphragm can be equal to or longer than the difference between the length of the second diaphragm supply path extending from the diaphragm supply unit to the winding unit and the length of the first diaphragm supply path extending from the diaphragm supply unit to the winding unit.

[0038] According to the twenty-sixth embodiment, a method for manufacturing an electrode assembly is provided, comprising: while supplying a first electrode, a first diaphragm, a second electrode, and a second diaphragm in a roll-to-roll manner, sequentially stacking and winding the first electrode, the first diaphragm, the second electrode, and the second diaphragm in one direction, wherein the first diaphragm and the second diaphragm are wound in an overlapping manner in a roll, and then unwinding and supplying them in a single sheet form.

[0039] Beneficial effects

[0040] Since the wound diaphragm of this disclosure is wound by stacking two or more diaphragms, each diaphragm can be provided as a single piece to different paths of the electrode assembly manufacturing apparatus.

[0041] In the winding diaphragm manufacturing method of this disclosure, unstretched sheets are prepared using a diluent and a polymer resin, and multiple unstretched sheets are stacked and stretched simultaneously. Therefore, a winding diaphragm manufacturing method with a simplified process can be provided.

[0042] Since the electrode assembly manufacturing apparatus of this disclosure uses a diaphragm supply unit, the wound diaphragm only needs to be replaced once when it is depleted, which facilitates the maintenance of the electrode assembly manufacturing apparatus.

[0043] Furthermore, since the electrode assembly manufacturing apparatus of this disclosure includes only one diaphragm supply unit, the process structure of the electrode assembly manufacturing apparatus can be simplified. For example, compared with the conventional case, the supply paths of the negative electrode, positive electrode, and diaphragm in the electrode assembly manufacturing apparatus of this disclosure are simplified.

[0044] The electrode assembly manufacturing method of this disclosure utilizes a wound diaphragm in which two or more diaphragms are stacked and wound, which simplifies the process. Furthermore, the electrode assembly manufacturing method of this disclosure enables a continuous process by replacing the wound diaphragm only once when the diaphragm is depleted. Attached Figure Description

[0045] The following figures illustrate embodiments of this disclosure and, together with the foregoing disclosure, serve to further understand the technical essence of this disclosure. Therefore, this disclosure should not be construed as limited to the content shown in the figures.

[0046] Figure 1 The structure of a wound diaphragm according to one embodiment of the present disclosure is illustrated schematically.

[0047] Figure 2 The structure of a wound diaphragm according to another embodiment of the present disclosure is shown schematically.

[0048] Figure 3The structure of an electrode assembly manufacturing apparatus according to one embodiment of the present disclosure is shown schematically.

[0049] Figure 4 The structure of an electrode assembly manufacturing apparatus according to another embodiment of the present disclosure is shown schematically.

[0050] Figure 5 The structure of an electrode assembly manufacturing apparatus according to yet another embodiment of the present disclosure is shown schematically.

[0051] Figure 6 This is a flowchart of an electrode assembly manufacturing method according to one embodiment of the present disclosure.

[0052] In the overall view of the accompanying drawings, corresponding reference numerals denote corresponding constituent elements. The drawings presented are for simplification and clarity only and are not necessarily drawn to scale. For example, the dimensions of some elements in the drawings may be enlarged relative to other elements to aid in a better understanding of the various embodiments. Furthermore, to make the views of the various embodiments clearer, common but well-known elements that are useful or necessary in commercially viable embodiments are generally omitted. Detailed Implementation

[0053] The words and terms used in the detailed description and claims herein should not be construed as limited to their ordinary or dictionary meanings, but should be interpreted as having meanings and concepts corresponding to the technical intent of this disclosure, in accordance with the principle that the inventors may appropriately define terms and concepts for the purpose of best describing this disclosure.

[0054] The terminology used herein is for describing exemplary embodiments only and is not intended to limit the scope of this disclosure. Unless the context clearly indicates otherwise, singular expressions include plural expressions.

[0055] <Definition>

[0056] Throughout this specification, when a part is referred to as "containing" a certain element, this does not exclude other elements, but rather includes them, unless otherwise expressly stated.

[0057] Throughout this specification, when referring to a layer being located on "a surface" or "one side" of another layer, this includes not only cases where the layer is in contact with a surface of another layer, but also cases where another layer exists between the two layers.

[0058] In the following detailed description, with reference to the accompanying drawings, embodiments of the present disclosure are provided to enable those skilled in the art to readily implement the present disclosure. However, the present disclosure can be implemented in many different forms and is not limited to the embodiments described herein. Furthermore, for clarity in the accompanying drawings, parts irrelevant to the description have been omitted, and similar parts are indicated by similar reference numerals throughout the specification.

[0059] An electrode assembly built into a battery casing is a rechargeable power generation device made of a stacked structure of a positive electrode, a separator, and a negative electrode, and is classified into jelly roll type, stacked type, and stacked / folded type. The jelly roll type involves inserting a separator between long, sheet-like positive and negative electrodes coated with active material and then rolling them up. The stacked type involves sequentially stacking multiple positive and negative electrodes of predetermined dimensions with a separator inserted between them. The stacked / folded type is a composite structure of the jelly roll and stacked types. Among these, the jelly roll type electrode assembly has the advantages of ease of manufacturing and high energy density per unit weight.

[0060] On the other hand, jelly roll-type electrode assemblies are formed by stacking a negative electrode, a separator on the negative electrode, a positive electrode on the separator, and a separator on the positive electrode. For this purpose, a winding device is typically required, comprising one negative electrode supply unit, one positive electrode supply unit, and two separator supply units. Each supply unit of the winding device is equipped with winding rolls on which the negative electrode, the positive electrode, and the separator are wound in sheet form. When material from any of the four winding rolls is exhausted or a process problem occurs, the winding process of the electrode assembly must be stopped. This is particularly problematic for the separator, as the presence of two winding rolls necessitates the replacement of the winding rolls twice. Furthermore, since the winding device must include one negative electrode supply unit, one positive electrode supply unit, and two separator supply units, the paths of the negative electrode, the positive electrode, and the separator, as well as the structure of the winding device itself, are complex and difficult to maintain.

[0061] In view of the above circumstances, this disclosure employs a single diaphragm supply unit, thereby providing a more maintenance-friendly jelly roll electrode assembly manufacturing apparatus and a simplified electrode assembly manufacturing method.

[0062] <Rolled diaphragm>

[0063] According to one embodiment, this disclosure provides a wound diaphragm (hereinafter also referred to as a "diaphragm wound roll"). The terms "diaphragm wound roll" and "wound diaphragm" are used interchangeably throughout the specification.

[0064] According to one aspect of this disclosure, a diaphragm winding in which two or more diaphragm layers are stacked and wound is provided. The number of diaphragm layers in the diaphragm winding of this disclosure is only required to be two or more, and there is no particular limitation on the number of diaphragm layers.

[0065] Figure 1 The structure of a diaphragm winding roll according to one embodiment of the present disclosure is illustrated schematically. Figure 2 The structure of a diaphragm winding roll according to another embodiment of the present disclosure is shown schematically.

[0066] In one embodiment of this disclosure, the diaphragm winding 10 may include a first diaphragm 11 and a second diaphragm 12, such as... Figure 1 As shown, two diaphragms 11 and 12 are stacked and wound into a single roll. In this case, the first diaphragm 11 may refer to the diaphragm closer to the center of the diaphragm roll 10 than the second diaphragm 12. The diaphragm roll 10 may have two stacked diaphragms 11 and 12 therein, such that one diaphragm roll 10 can be used to provide each of the diaphragms 11 and 12 in monolithic form for different paths in the electrode assembly manufacturing apparatus 100.

[0067] In one embodiment of this disclosure, the winding length of the first diaphragm 11 and the winding length of the second diaphragm 12 may be the same as each other. Alternatively, the winding length of the second diaphragm 12 may be longer than the winding length of the first diaphragm 11. In this case, "winding length" refers to the total length of the diaphragm wound in the diaphragm winding roll 10 in the longitudinal direction.

[0068] In one embodiment of this disclosure, when the winding length of the first diaphragm 11 and the winding length of the second diaphragm 12 are the same, the first diaphragm 11 or the second diaphragm 12 may be exhausted first, but there is an advantage that the diaphragm winding roll 10 is easy to store.

[0069] In one embodiment of this disclosure, when the winding length of the second diaphragm 12 is longer than the winding length of the first diaphragm 11, the first diaphragm 11 and the second diaphragm 12 can separate naturally without the aid of any additional device. The difference between the winding length of the second diaphragm 12 and the winding length of the first diaphragm 11 can be adjusted to suit the desired purpose using the electrode assembly manufacturing apparatus 100 in which the diaphragm winding roll 10 is used.

[0070] In one embodiment of this disclosure, when unwinding the diaphragm winding 10, the first diaphragm 11 and the second diaphragm 12 can be unwound simultaneously, or one of the first diaphragm 11 and the second diaphragm 12 can be unwound before the other.

[0071] In one embodiment of this disclosure, the wound ends of the first diaphragm 11 and the second diaphragm 12 may overlap at the same location. As another example, one of the wound ends of the first diaphragm 11 and the second diaphragm 12 may be wound in a manner that wraps around the other.

[0072] like Figure 1 As shown, the second diaphragm 12 can be wound in a manner that wraps around the first diaphragm 11, such that during unwinding, the second diaphragm 12 unwinds before the first diaphragm 11. Using the method described above, the two or more diaphragms 11 and 12 can naturally separate into the first diaphragm 11 and the second diaphragm 12 without the need for additional devices.

[0073] On the other hand, the diaphragm winding 10 of this disclosure may include a first diaphragm 11, a second diaphragm 12, and a third diaphragm 13, such as Figure 2 As shown, these three diaphragms 11, 12, and 13 can be stacked and wound into a single roll. In this case, the first diaphragm 11 can refer to the diaphragm closer to the center of the diaphragm winding roll 10 than the second diaphragm 12 and the third diaphragm 13. Furthermore, the second diaphragm 12 can refer to the diaphragm closer to the center of the diaphragm winding roll 10 than the third diaphragm 13. Figure 2 As shown, this disclosure is a diaphragm winding roll 10 in which multiple diaphragms are stacked and wound, and although Figure 2 The stacked three-layer diaphragms 11, 12, and 13 are shown only by way of example, but the number of stacked diaphragms can be increased without limitation. On the other hand, as used herein, diaphragms in which two or more layers of diaphragms are stacked are also referred to as “overlapping wound diaphragms”.

[0074] In one embodiment of this disclosure, the winding length of the diaphragm can be about 100 m to 10,000 m, 1,000 m to 7,000 m, or 2,000 m to 5,000 m.

[0075] In one embodiment of this disclosure, the diaphragm winding may have two or more diaphragms wound on a spool, but the diaphragm winding may not include the spool.

[0076] In one embodiment of this disclosure, two or more diaphragms wound in the diaphragm winding may each comprise a porous polymer substrate.

[0077] In this specification, when the diaphragm comprises only a porous polymer substrate, the diaphragm and the porous polymer substrate can be used as the same material. On the other hand, when the diaphragm comprises an inorganic heat-resistant layer on the porous polymer substrate, the diaphragm can comprise both a porous polymer substrate and an inorganic heat-resistant layer.

[0078] In one embodiment of this disclosure, the porous polymer substrate refers to a substrate having multiple pores that act as a porous ion-conducting barrier, blocking electrical contact between the negative and positive electrodes while allowing ions to pass through. The pores are interconnected, allowing gas or liquid to pass from one side of the substrate to the other.

[0079] In one embodiment of this disclosure, the porous polymer substrate may be, for example, a porous polymer membrane substrate or a porous polymer nonwoven fabric substrate.

[0080] The material constituting the porous polymer substrate can be any organic or inorganic material with electrical insulating properties. From the viewpoint of imparting a closed-cell function to the porous polymer substrate, thermoplastic resin can be used as a constituent material of the porous polymer substrate. The closed-cell function refers to the function that, when the battery temperature rises, the thermoplastic resin melts and closes the pores of the porous substrate, thereby blocking ion movement and suppressing thermal runaway of the battery.

[0081] The porous polymer substrate may be a porous polymer substrate made of polyolefins such as polyethylene or polypropylene, and the polyolefin porous polymer substrate exhibits closed-cell function at temperatures, for example, 80°C to 130°C.

[0082] The polyolefin porous polymer substrate can be formed into a polymer by using polyethylene such as high-density polyethylene, linear low-density polyethylene, low-density polyethylene or ultra-high molecular weight polyethylene, polypropylene, polybutene or polypentene alone or in mixtures of two or more thereof.

[0083] In addition to polyolefins, the porous polymer substrate can also be prepared by molding various polymers such as polyesters into a film. Furthermore, the porous polymer substrate can be formed into a structure in which two or more porous polymer substrates are stacked, and each layer can be formed by polymers such as the aforementioned polyolefins, polyesters, or other polymers alone or by a mixture of two or more thereof.

[0084] In addition to the aforementioned polyolefin materials, the porous polymer substrate may also be formed from polyethylene terephthalate, polybutylene terephthalate, polyester, polyacetal, polyamide, polycarbonate, polyimide, polyetheretherketone, polyethersulfone, polyphenylene ether, polyphenylene sulfide, polyethylene naphthalate alone or in mixtures thereof.

[0085] There is no particular limitation on the thickness of the porous polymer substrate, but it can be from about 1 μm to 100 μm or from about 5 μm to 50 μm. Furthermore, there is no particular limitation on the pore size and pore content present in the porous polymer substrate, but they can be from about 0.01 μm to 50 μm and from about 10% to 95%, respectively.

[0086] As used in this article, the terms “about,” “approximately,” and “basically” are intended to refer to the range or vicinity of inherent manufacturing and material tolerances in terms of value or degree.

[0087] In one embodiment of this disclosure, the weight-average molecular weight of the polyolefin can be from 100,000 to 5,000,000. When the weight-average molecular weight is less than 100,000, it may be difficult to ensure sufficient mechanical properties. Furthermore, when the weight-average molecular weight exceeds 5,000,000, closed-cell properties may deteriorate or molding may become difficult. Additionally, from the viewpoint of improving manufacturing yield, the puncture strength of the porous polymer substrate can be 300 gf or higher. The puncture strength of the porous substrate refers to the maximum puncture load (gf) measured using a Kato tech KES-G5 handheld compression tester under conditions of a needle tip curvature radius of 0.5 mm and a puncture speed of 4 mm / s.

[0088] In one embodiment of this disclosure, when the separator comprises only the porous polymer substrate, even when two or more separators are stacked and wound, the separators do not adhere to each other, allowing them to separate naturally when separated into individual sheets without additional force or means. Therefore, when separators with two or more layers are overlapped and wound, no intermediate layer film, such as release paper, is needed to separate the two or more separators, thus providing a process advantage.

[0089] On the other hand, in one embodiment of this disclosure, the diaphragm may optionally include an inorganic heat-resistant layer on at least one surface of the porous polymer substrate, i.e., the diaphragm. The inorganic heat-resistant layer may comprise inorganic particles and a binder polymer.

[0090] For example, the two or more diaphragms may include a first diaphragm and a second diaphragm. The first diaphragm may include a first porous polymer substrate and a first inorganic heat-resistant layer on at least one surface of the first porous polymer substrate. The first inorganic heat-resistant layer includes first inorganic particles and a first adhesive polymer. The second diaphragm may include a second porous polymer substrate and a second inorganic heat-resistant layer on at least one surface of the second porous polymer substrate. The second inorganic heat-resistant layer includes second inorganic particles and a second adhesive polymer.

[0091] In one embodiment of this disclosure, the first adhesive polymer and the second adhesive polymer (hereinafter also referred to as adhesive polymers) can serve to connect and fix inorganic particles within the inorganic heat-resistant layer.

[0092] In one embodiment of this disclosure, the adhesive polymer may comprise a particulate adhesive polymer or a non-particulate adhesive polymer. A “particulate” adhesive polymer may refer to an adhesive polymer that is added to the dispersion medium in particulate form and retains the shape of the added particles after coating and drying. A “non-particulate” adhesive polymer may refer to an adhesive polymer that is coated and dried in a solvent-dissolved form when forming an inorganic heat-resistant layer, or that is added to the dispersion medium in particulate form but does not retain the particulate form upon coating and drying.

[0093] In one embodiment of this disclosure, non-limiting examples of the adhesive polymer include, but are not limited to, polyvinylidene fluoride, polyvinylidene fluoride-co-hexafluoropropylene, polyvinylidene fluoride-co-trichloroethylene, polymethyl methacrylate, polybutyl acrylate, polyacrylonitrile, polyvinylpyrrolidone, polyvinyl acetate, polyvinyl co-vinyl acetate, polyethylene oxide, polyarylates, cellulose acetate, cellulose acetate butyrate, cellulose acetate propionate, cyanoethyl pullulan, cyanoethyl polyvinyl alcohol, cyanoethyl cellulose, cyanoethyl sucrose, pullulan, polyacrylic acid, and carboxymethyl cellulose.

[0094] In one embodiment of this disclosure, the first adhesive polymer and the second adhesive polymer may be the same or different. For example, since the first adhesive polymer and the second adhesive polymer are of different types depending on the electrode they are facing, the negative electrode-separator adhesion and the positive electrode-separator adhesion can be controlled.

[0095] According to one embodiment of this disclosure, the adhesive polymer can be classified into dispersant-type adhesive polymers (also used as dispersants) and non-dispersant-type adhesive polymers. The dispersant-type adhesive polymer is a polymer having at least one dispersant functional group in its main chain or side chain, and the dispersant functional group may be, for example, an OH group or a CN group. Examples of such dispersant-type adhesive polymers include cellulose acetate, cellulose acetate butyrate, cellulose acetate propionate, cyanoethyl pullulan, cyanoethyl polyvinyl alcohol, cyanoethyl cellulose, cyanoethyl sucrose, and pullulan and carboxymethyl cellulose. The non-dispersant-type adhesive polymer may include examples of the adhesive polymers excluding dispersant-type adhesive polymers.

[0096] There is no particular limitation on the inorganic particles as long as they are electrochemically stable. For example, there is no particular limitation on the inorganic particles that can be used herein as long as they do not undergo oxidation and / or reduction reactions within the operating voltage range of the electrochemical device to be applied (e.g., based on Li / Li + is 0 V to 5 V). In particular, using inorganic particles with a high dielectric constant can help improve the dissociation of electrolyte salts such as lithium salts in the liquid electrolyte, thereby increasing the ionic conductivity of the electrolyte.

[0097] Non-limiting examples of the inorganic particles include high dielectric constant inorganic particles with a dielectric constant of about 5 or more or about 10 or more, inorganic particles having lithium ion transport ability, or mixtures thereof.

[0098] Non-limiting examples of the inorganic particles with a dielectric constant of 5 or more include BaTiO3, Pb(Zr,Ti)O3 (PZT), Pb 1-x La x Zr 1-y Ti y O3 (PLZT), Pb(Mg 1 / 3 Nb 2 / 3 )O3-PbTiO3 (PMN-PT), hafnium dioxide (HfO2), SrTiO3, SnO2, CeO2, MgO, NiO, CaO, ZnO, ZrO2, Y2O3, Al2O3, TiO2, SiC, AlO(OH), and Al2O3·H2O, or mixtures thereof.

[0099] The inorganic particles having lithium ion transport ability refer to inorganic particles that contain lithium element and have the ability to transfer lithium ions without storing lithium. Non-limiting examples of the inorganic particles having lithium ion transport ability include lithium phosphate (Li3PO4), lithium titanium phosphate (Li x Ti y (PO4)3, 0 < x < 2, 0 < y < 3), lithium aluminum titanium phosphate (Li x Al y Ti z (PO4)3, 0 < x < 2, 0 < y < 1, 0 < z < 3), (LiAlTiP) x O y series glasses (0 < x < 4, 0 < y < 13) such as 14Li2O-9Al2O3-38TiO2-39P2O5, lithium lanthanum titanate (Li x La y TiO3, 0 < x < 2, 0 < y < 3), lithium germanium thiophosphate (Li x Ge y P z S[[ID=第48行]] w, 0 < x < 4, 0 < y < 1, 0 < z < 1, w < 5), such as Li 3.25 Ge 0.25 P 0.75 S4, lithium nitride (Li x N y , 0 < x < 4, 0 < y < 2), such as Li3N, SiS2 series glass (Li x Si y S z , 0 < x < 3, 0 < y < 2, 0 < z < 4), such as Li3PO4 - Li2S - SiS2, and P2S5 series glass (Li x P y S z , 0 < x < 3, 0 < y < 3, 0 < z < 7), such as LiI - Li2S - P2S5, or a mixture thereof.

[0100] There is no particular limitation on the thickness of the inorganic heat - resistant layer, but it can be about 1 μm to 10 μm or about 1.5 μm to 6 μm, and there is also no particular limitation on the porosity of the above - mentioned inorganic heat - resistant layer, but it can be about 35% to 65%.

[0101] In one embodiment of the present disclosure, based on 100% by weight of the inorganic heat - resistant layer, the content of the inorganic particles can be about 80% to 95% by weight, 85% to 93% by weight, or 90% to 92% by weight. When the content of the inorganic particles satisfies the above range, the inorganic heat - resistant layer can have a high density, and the porosity and resistance characteristics of the separator can be excellent.

[0102] In one embodiment of the present disclosure, based on 100% by weight of the inorganic heat - resistant layer, the content of the binder polymer can be about 5% to 20% by weight or 10% to 15% by weight. When the content of the binder polymer satisfies the above range, the heat resistance of the separator can be excellent without causing the detachment of the inorganic particles in the inorganic heat - resistant layer.

[0103] On the other hand, when the inorganic heat - resistant layer is formed on the separator, an intermediate layer film can be further included on at least one of the first inorganic heat - resistant layer and the second inorganic heat - resistant layer. For example, the intermediate layer film can be included between the first inorganic heat - resistant layer and the second inorganic heat - resistant layer, the intermediate layer film can be included between the first inorganic heat - resistant layer and the second porous polymer substrate, and the intermediate layer film can be included between the second inorganic heat - resistant layer and the first porous polymer substrate.

[0104] In one embodiment of this disclosure, depending on the content of the binder polymer in the inorganic heat-resistant layer, the binder polymer may be present inside the inorganic heat-resistant layer to bind the inorganic particles, while the binder may also be present on the surface of the inorganic heat-resistant layer. In this case, it may be difficult to supply the first membrane and the second membrane separately. Therefore, in this case, at least one of the first inorganic heat-resistant layer and the second inorganic heat-resistant layer may further include an intermediate layer membrane to facilitate the separation of the first membrane and the second membrane.

[0105] In one embodiment of this disclosure, the interlayer film is also referred to as a release film, and the type of the interlayer film is not limited, but may be, for example, a PET film.

[0106] <Manufacturing method of diaphragm winding>

[0107] According to one embodiment, this disclosure provides a method for manufacturing a diaphragm winding roll.

[0108] According to one aspect of this disclosure, a method for manufacturing a diaphragm winding is provided, comprising: introducing a first mixture comprising a first diluent and a first polymer resin into an extruder, subsequently extruding and cooling to obtain a first unstretched sheet; introducing a second mixture comprising a second diluent and a second polymer resin into an extruder, subsequently extruding and cooling to obtain a second unstretched sheet; stacking the first unstretched sheet and the second unstretched sheet to obtain an unstretched stacked sheet; performing a first stretch on the unstretched stacked sheet in a first direction to obtain a first stretched stacked sheet; performing a second stretch on the first stretched stacked sheet in a second direction to obtain a second stretched stacked sheet; extracting the first diluent and the second diluent from the second stretched stacked sheet to obtain a stacked diaphragm wherein the first diaphragm and the second diaphragm are stacked; and winding the stacked diaphragm obtained in the extraction.

[0109] The method for manufacturing the diaphragm winding is described in detail below.

[0110] First, a first mixture of a first diluent and a first polymer resin is introduced into an extruder, then extruded and cooled to obtain a first unstretched sheet. Then, a second mixture of a second diluent and a second polymer resin is introduced into the extruder, then extruded and cooled to obtain a second unstretched sheet.

[0111] In one embodiment of this disclosure, the materials of the first polymer resin and the second polymer resin may include polyethylene (such as high-density polyethylene, linear low-density polyethylene, low-density polyethylene, and ultra-high molecular weight polyethylene), polypropylene, polybutene, polypentene, polyester, polyethylene terephthalate, polybutylene terephthalate, polyester, polyacetal, polyamide, polycarbonate, polyimide, polyetheretherketone, polyethersulfone, polyphenylene ether, polyphenylene sulfide, polyethylene naphthalate, or mixtures of two or more thereof. The first polymer resin and the second polymer resin may each contain polyethylene (such as high-density polyethylene, linear low-density polyethylene, low-density polyethylene, and ultra-high molecular weight polyethylene), polypropylene, polybutene, polypentene, or mixtures thereof.

[0112] In one embodiment of this disclosure, the first and second diluents may each be diluents commonly used in the manufacture of wet diaphragms, and examples include: liquid or solid paraffin oil, wax, soybean oil; phthalates such as dibutyl phthalate, dihexyl phthalate, and dioctyl phthalate; aromatic ethers such as diphenyl ether and benzyl ether; fatty acids having 10 to 20 carbon atoms such as palmitic acid, stearic acid, oleic acid, linoleic acid, and linolenic acid; and fatty acids having 10 to 20 carbon atoms. Fatty alcohols with carbon atoms, such as palmitol, stearyl alcohol, and oleyl alcohol; wherein fatty acid esters formed by ester bonding of a saturated or unsaturated fatty acid having 4 to 26 carbon atoms in its fatty acid group, or a fatty acid in which one or more double bonds of an unsaturated fatty acid are replaced by an epoxy group, to an alcohol having 1 to 8 hydroxyl groups and 1 to 10 carbon atoms, such as palmitic acid monoester, diester, or triester; stearic acid monoester, diester, or triester; oleic acid monoester, diester, or triester; and linoleic acid monoester, diester, or triester; but not limited thereto. The diluent may be used alone or as a mixture containing at least two of the above-mentioned components.

[0113] In one embodiment of this disclosure, the content of the first diluent or the second diluent may be added at a conventional addition level, and based on 100 parts by weight of the first mixture or the second mixture, it may be 100 to 350 parts by weight, or 125 to 300 parts by weight, or 150 to 250 parts by weight, but is not limited thereto.

[0114] In one embodiment of this disclosure, the first mixture and the second mixture may contain other conventional additives in addition to diluents to improve specific functions, such as antioxidants, initiators, crosslinking agents, crosslinking catalysts, surfactants, UV stabilizers, antistatic agents, and nucleating agents.

[0115] In one embodiment of this disclosure, the extruder may be a single-screw extruder or a twin-screw extruder, and is equipped with a T-die as the discharge section. When using a T-die as the discharge section, a diaphragm with excellent thickness uniformity can be obtained. After the first mixture and the second mixture are each introduced into the extruder, a melt composition can be obtained by mixing them while melting the polymer resin at a high temperature.

[0116] Subsequently, the molten first and second mixtures can be extruded through an extruder equipped with a T-die, and then subjected to conventional casting or calendering using water cooling or air cooling to obtain sheet-like first and second unstretched sheets, respectively.

[0117] On the other hand, as the extrudate is cooled by the cooling process, the polymer resin and the diluent may undergo phase separation.

[0118] Subsequently, the first unstretched sheet and the second unstretched sheet are stacked to obtain an unstretched stacked sheet. The first unstretched sheet and the second unstretched sheet can be physically recombine and stacked.

[0119] In one embodiment of this disclosure, the dimensions of the first unstretched sheet and the second unstretched sheet may be the same as or different from each other.

[0120] Then, the unstretched stacked sheet is first stretched in a first direction, and the first stretched stacked sheet is second stretched in a second direction.

[0121] In one embodiment of this disclosure, the first stretching and the second stretching may be performed simultaneously or sequentially, for example, by rollers or by a tenter frame.

[0122] In one embodiment of this disclosure, the first direction and the second direction may be the same as or different from each other.

[0123] Furthermore, in one embodiment of this disclosure, the first direction and the second direction may each be independently a direction parallel to the machine direction (MD) or the transverse direction (TD).

[0124] As used herein, "machine orientation" refers to the process in the manufacture of the diaphragm (extrusion). Forming The direction parallel to the direction of travel of the stretching…. The machine direction can be determined by the fiber orientation direction of the polymer in the diaphragm substrate, and the direction parallel to the fiber orientation direction is the machine direction.

[0125] Accordingly, "lateral" refers to a direction orthogonal to the machine direction. The lateral direction can also be defined as a direction orthogonal to the fiber orientation direction of the polymer in the diaphragm substrate.

[0126] In one embodiment of this disclosure, the first direction may typically be a direction parallel to the MD, and the second direction may be a direction parallel to the TD, but this disclosure is not limited thereto.

[0127] In one embodiment of this disclosure, the first direction may be a direction parallel to the TD, and the second direction may be a direction parallel to the MD.

[0128] In one embodiment of this disclosure, the stretching ratio of the first stretching and the second stretching can be, for example, more than 3 times or 5 to 12 times in the machine direction or the transverse direction, and the total stretching ratio can be 20 to 120 times. When the stretching ratio meets the above-mentioned numerical range, there may be advantageous effects in terms of the thickness uniformity of the manufactured diaphragm substrate and the balance of physical properties between the longitudinal and transverse directions, but this disclosure is not limited thereto.

[0129] In one embodiment of this disclosure, the stretching temperature may vary depending on the melting point of the polymer resin used and the concentration and type of the diluent, but this disclosure is not limited thereto.

[0130] Next, the diluent is extracted from the second stretched stacked sheet to obtain a stacked diaphragm in which the first diaphragm and the second diaphragm are stacked.

[0131] In one embodiment of this disclosure, the diluent can be extracted using an organic solvent. There are no particular limitations on the organic solvent, as long as it can extract the diluent; however, methyl ethyl ketone, dichloromethane, hexane, or mixtures of two or more thereof, which have high extraction efficiency and fast drying, may be suitable.

[0132] In one embodiment of this disclosure, the extraction method can be any conventional solvent extraction method, such as impregnation, solvent spraying, and ultrasonication, which can be used alone or in combination. The residual diluent content after the extraction treatment can be less than 1% by weight based on 100% by weight of the resulting stacked diaphragm. When the residual diluent content exceeds 1% by weight, the physical properties deteriorate, and the permeability of the diaphragm decreases. The residual diluent content may be affected by the extraction temperature and extraction time. To improve the solubility of the diluent and the organic solvent, a high extraction temperature is desirable; however, considering safety concerns due to the boiling of the organic solvent, the extraction temperature can be below 40°C. When the extraction temperature is below the freezing point of the diluent, the extraction efficiency decreases significantly. Therefore, the extraction temperature must be above the freezing point of the diluent.

[0133] In one embodiment of this disclosure, a step of heat-fixing the stacked diaphragms may also be included. Heat-fixing may refer to applying heat to the diaphragms, thereby fixing the diaphragms and forcibly holding the porous membrane as it is to be shrunk, thereby removing residual stress.

[0134] In one embodiment of this disclosure, the heat-setting temperature can be, for example, about 120°C to 140°C or 125°C to 135°C. When the heat-setting temperature exceeds the upper limit, the porous polymer substrate fractures; when the heat-setting temperature is below the lower limit, the stress release of the porous polymer substrate may be insufficient.

[0135] The resulting stacked diaphragms are then wound to obtain a diaphragm winding roll.

[0136] In one embodiment of this disclosure, the first mixture may further include a first initiator and a first crosslinking agent, the second mixture may further include a second initiator and a second crosslinking agent, and the method may further include crosslinking the stacked membrane obtained by extracting the diluent.

[0137] In one embodiment of this disclosure, when both the first polymer resin and the second polymer resin are polyolefins, the crosslinking agent can be any crosslinking agent commonly used in the manufacture of polyolefin crosslinked membranes. For example, the first crosslinking agent and the second crosslinking agent can each be, for example, an alkoxysilane compound containing a carbon-carbon double bond group that induces a silane crosslinking reaction. For instance, the alkoxysilane compound containing a carbon-carbon double bond group is grafted onto the polyolefin via the carbon-carbon double bond group and crosslinked via the alkoxy group, thereby crosslinking the polyolefin. This can increase the melting temperature of the membrane.

[0138] The carbon-carbon double bond group is a reactive group that can be grafted onto polyolefins as described above, and is a substituent having a double bond between two carbon atoms. Examples include vinyl, acryloyloxy, or methacryloyloxy.

[0139] In one embodiment of this disclosure, the alkoxysilane compound containing a carbon-carbon double bond group may include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltriacetoxysilane, (3-methacryloyloxypropyl)trimethoxysilane, (3-methacryloyloxypropyl)triethoxysilane, vinylmethyldimethoxysilane, vinyl-tris(2-methoxyethoxy)silane, vinylmethyldiethoxysilane, or a mixture of at least two or more thereof.

[0140] In one embodiment of this disclosure, based on 100% by weight of the first mixture, the content of the first crosslinking agent may be from about 0.1% by weight to 3.0% by weight, or from 0.15% by weight to 2.0% by weight, or from 0.2% by weight to 1.5% by weight.

[0141] In one embodiment of this disclosure, based on 100% by weight of the second mixture, the content of the second crosslinking agent may be from about 0.1% by weight to 3.0% by weight, or from 0.15% by weight to 2.0% by weight, or from 0.2% by weight to 1.5% by weight.

[0142] In one embodiment of this disclosure, the first initiator and the second initiator may be, but are not limited to, any initiator capable of generating free radicals. The first initiator and the second initiator may be, for example, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane (DHBP), benzoyl peroxide, acetyl peroxide, dilauryl peroxide, di-tert-butyl peroxide, dicumyl peroxide, cumyl peroxide, hydrogen peroxide, potassium persulfate, or combinations thereof.

[0143] In one embodiment of this disclosure, based on 100% by weight of the first crosslinking agent, the content of the first initiator may be from about 0.1% by weight to 20% by weight, or from 0.5% by weight to 10% by weight, or from 1% by weight to 5% by weight.

[0144] In one embodiment of this disclosure, based on 100% by weight of the second crosslinking agent, the content of the second initiator may be from about 0.1% by weight to 20% by weight, or from 0.5% by weight to 10% by weight, or from 1% by weight to 5% by weight.

[0145] In one embodiment of this disclosure, when the first mixture further comprises the first initiator and the first crosslinking agent, and the second mixture further comprises the second initiator and the second crosslinking agent, the stacked membrane obtained by extracting the diluent can be crosslinked after heat fixation.

[0146] In one embodiment of this disclosure, the crosslinking can be water crosslinking, and the water crosslinking can be carried out at 60°C to 100°C, or 65°C to 95°C, or 70°C to 90°C. In a specific embodiment of this disclosure, the water crosslinking can be carried out at 60% to 95% humidity for 6 to 50 hours.

[0147] According to another aspect of this disclosure, a method for manufacturing a diaphragm winding is provided, comprising: introducing a third mixture comprising a third diluent and a third polymer resin into an extruder, subsequently extruding and cooling to obtain a third unstretched sheet; introducing a fourth mixture comprising a fourth diluent and a fourth polymer resin into an extruder, subsequently extruding and cooling to obtain a fourth unstretched sheet; subjecting the third unstretched sheet and the fourth unstretched sheet to a first stretch in a first direction to obtain a first-stretched third sheet and a first-stretched fourth sheet; subjecting the first-stretched third sheet and the first-stretched fourth sheet to a second stretch in a second direction to obtain a second-stretched third sheet and a second-stretched fourth sheet; and from the second-stretched third sheet... The third diluent and the fourth diluent are extracted from the three sheets and the fourth sheet after the second stretching, respectively, to obtain a third porous polymer substrate and a fourth porous polymer substrate; a slurry for forming a third inorganic heat-resistant layer, comprising third inorganic particles and a third binder polymer, is applied to at least one surface of the third porous polymer substrate and dried to form a third inorganic heat-resistant layer; a slurry for forming a fourth inorganic heat-resistant layer, comprising fourth inorganic particles and a fourth binder polymer, is applied to at least one surface of the fourth porous polymer substrate and dried to form a fourth inorganic heat-resistant layer; and the third porous polymer substrate on which the third inorganic heat-resistant layer is formed and the fourth porous polymer substrate on which the fourth inorganic heat-resistant layer is formed are stacked and wound together.

[0148] The method for manufacturing the diaphragm winding is described in detail below.

[0149] First, a third mixture of a third diluent and a third polymer resin is introduced into an extruder, then extruded and cooled to obtain a third unstretched sheet. Then, a fourth mixture of a fourth diluent and a fourth polymer resin is introduced into an extruder, then extruded and cooled to obtain a fourth unstretched sheet.

[0150] The third and fourth diluents are the same as the first and second diluents, respectively, and are used in place of the aforementioned diluents.

[0151] Furthermore, the third polymer resin and the fourth polymer resin are the same as the first polymer resin and the second polymer resin, respectively, and are used in place of the aforementioned polymer resin.

[0152] Then, the third unstretched sheet and the fourth unstretched sheet are stretched in the first direction, and the third and fourth sheets after the first stretching are stretched in the second direction.

[0153] The stretching step can be the same as described above.

[0154] On the other hand, the stretching step can be performed by stacking the third unstretched sheet and the fourth unstretched sheet to obtain an unstretched stacked sheet, and then stretching the stacked sheet.

[0155] Subsequently, the third and fourth diluents are extracted from the second stretched sheet to obtain the third and fourth porous polymer substrates, respectively. The third and fourth diluents are the same as the first and second diluents, respectively, and are used in place of the aforementioned diluents.

[0156] According to one embodiment of this disclosure, the method may further include the step of heat-fixing the third porous polymer substrate and the fourth porous polymer substrate obtained by extracting the third diluent and the fourth diluent, respectively. The heat-fixing step is as described above.

[0157] Subsequently, a slurry for forming a third inorganic heat-resistant layer, comprising third inorganic particles and a third binder polymer, is applied to at least one surface of the obtained third porous polymer substrate and dried to form a third inorganic heat-resistant layer; and a slurry for forming a fourth inorganic heat-resistant layer, comprising fourth inorganic particles and a fourth binder polymer, is applied to at least one surface of the obtained fourth porous polymer substrate and dried to form a fourth inorganic heat-resistant layer.

[0158] The aforementioned can be replaced by the third inorganic particles, the fourth inorganic particles, the third adhesive polymer, and the fourth adhesive polymer.

[0159] In one embodiment of this disclosure, the third inorganic heat-resistant layer forming slurry and the fourth inorganic heat-resistant layer forming slurry (hereinafter also referred to as inorganic heat-resistant layer forming slurry) each contain inorganic particles and binder polymer in the dispersion medium.

[0160] In one embodiment of this disclosure, the dispersion medium is an aqueous dispersion medium. The aqueous dispersion medium can be water or an aqueous dispersion medium containing water. Furthermore, when there are limitations on drying speed and temperature, methanol, ethanol, isopropanol, etc., having 1 to 5 carbon atoms and a boiling point lower than water, can be used. In the manufacturing method, by using an aqueous dispersion medium, the particulate binder polymer is dispersed in the dispersion medium while remaining in a particulate form without dissolving.

[0161] On the other hand, in one embodiment of this disclosure, the aqueous inorganic heat-resistant layer forming slurry and the aqueous adhesive layer forming slurry can be controlled such that the concentration of solids (or the content of solids) after excluding the dispersion medium is in the range of 20% by weight to 50% by weight.

[0162] In one embodiment of this disclosure, there is no limitation on the method of applying the aqueous inorganic heat-resistant layer forming slurry to at least one surface of the porous polymer substrate. For example, various methods can be used as the application method, such as dip coating, die coating, roll coating, comma coating, microgravure coating, doctor blade coating, reverse roll coating, Mayer bar coating, direct metering coating, or combinations thereof.

[0163] In one embodiment of this disclosure, the drying method for the slurry used to form the aqueous inorganic heat-resistant layer is not limited to a specific method. For example, one or more of the following methods can be used: convection drying, hot air drying, blowing drying, and natural drying. The drying method can be hot air drying.

[0164] In one embodiment of this disclosure, the drying step can be performed at a temperature of 55°C to 68°C. When the temperature of the drying step meets the above range, the defined inorganic particles can be arranged in the inorganic heat-resistant layer, thereby achieving better durability and mechanical strength.

[0165] In one embodiment of this disclosure, the drying step may be performed for 10 to 120 seconds within the aforementioned temperature range.

[0166] Then, the third porous polymer substrate on which the third inorganic heat-resistant layer is formed and the fourth porous polymer substrate on which the fourth inorganic heat-resistant layer is formed are stacked and wound together.

[0167] In one embodiment of this disclosure, the winding step may include further stacking an interlayer film on at least one of the third inorganic heat-resistant layer and the fourth inorganic heat-resistant layer, followed by winding. The third and fourth interlayer films are identical to the first and second interlayer films described above, respectively, and are used in place of the aforementioned interlayer films.

[0168] In one embodiment of this disclosure, the third mixture may further include a third initiator and a third crosslinking agent, the fourth mixture may further include a fourth initiator and a fourth crosslinking agent, and the method may further include the step of crosslinking the third porous polymer substrate and the fourth porous polymer substrate obtained by extracting the third diluent and the fourth diluent, respectively.

[0169] The third and fourth initiators are the same as the first and second initiators, respectively, and are used in place of the aforementioned initiators.

[0170] The third and fourth crosslinking agents are the same as the first and second crosslinking agents, respectively, and are used in place of the aforementioned crosslinking agents.

[0171] <Electrode Assembly Manufacturing Equipment>

[0172] This disclosure provides an electrode assembly manufacturing apparatus comprising the aforementioned diaphragm winding.

[0173] An electrode assembly manufacturing apparatus 100 according to one embodiment of this disclosure can be configured to sequentially stack and wind the first electrode 14, the first diaphragm 11, the second electrode 15, and the second diaphragm 12 in one direction while supplying them in a roll-to-roll manner. The first diaphragm 11 and the second diaphragm 12 are wound in an overlapping manner in a single roll, and then unwound and supplied as individual sheets. For example, the electrode assembly manufacturing apparatus 100 is configured to manufacture an electrode assembly using the aforementioned overlapping and wound diaphragms.

[0174] Figure 3 The structure of an electrode assembly manufacturing apparatus 100 according to one embodiment of the present disclosure is shown schematically. Figure 4 The structure of an electrode assembly manufacturing apparatus 100 according to another embodiment of the present disclosure is shown schematically. Figure 5 The structure of an electrode assembly manufacturing apparatus 100 according to yet another embodiment of the present disclosure is shown schematically.

[0175] First, refer to Figure 3 The electrode assembly manufacturing apparatus 100 includes a diaphragm supply unit 110 that supplies two or more diaphragms individually separated from a diaphragm winding roll 10 in which two or more diaphragms are stacked and wound; a first electrode supply unit 120 that supplies a first electrode 14; a second electrode supply unit 130 that supplies a second electrode 15; and a winding unit 140 that stacks and winds the individually separated diaphragms between the first electrode 14 and the second electrode 15 and on the outside of the first electrode 14 or the second electrode 15.

[0176] The diaphragm supply unit 110, the first electrode supply unit 120, and the second electrode supply unit 130 can be configured to unwind and continuously supply the first diaphragm 11, the second diaphragm 12, the first electrode 14, and the second electrode 15 wound into rolls. The winding unit 140 can be configured to stack the first electrode 14, the first diaphragm 11, the second electrode 15, and the second diaphragm 12 sequentially and wind them in one direction to form a roll. Therefore, the apparatus can be configured in a roll-to-roll manner, thereby enabling continuous processing. In this case, since the electrode assembly manufacturing apparatus 100 of this disclosure uses only one diaphragm supply unit 110, the diaphragm winding roll 10 only needs to be replaced once when the diaphragm is depleted, which is beneficial for maintenance. Since only one diaphragm supply unit 110 can be included, the process structure of the electrode assembly manufacturing apparatus 100 can be simplified. Furthermore, compared with the conventional case, the paths of the negative electrode, the positive electrode, and the diaphragm in the electrode assembly manufacturing apparatus 100 can be simplified.

[0177] In one embodiment of this disclosure, the winding unit 140 is an apparatus for winding the first electrode 14, the second electrode 15, and the first and second diaphragms 11 and 12, and is also referred to as a mandrel. The winding unit 140 may include a core and a motor for rotating the core. After the first electrode 14, the first and second diaphragms 11 and 12, and the second electrode 15 are supplied, the winding unit 140 rotates, and the first electrode 14, the second electrode 15, and the diaphragms 11 and 12 are pulled by the rotational force of the winding unit 140, making it possible to manufacture an electrode assembly.

[0178] In one embodiment of this disclosure, the first electrode 14 may be a negative electrode, and the second electrode 15 may be a positive electrode. Alternatively, the first electrode 14 may be a positive electrode, and the second electrode 15 may be a negative electrode.

[0179] The first electrode supply unit 120 supplies the first electrode 14 to the winding unit 140. For this purpose, the first electrode supply unit 120 may include a winding roll on which the first electrode 14, cut into sheet shapes, is wound. Furthermore, the first electrode supply unit 120 may include other components such as shafts and rollers necessary for mounting and unwinding the winding roll. The second electrode supply unit 130 supplies the second electrode 15 to the winding unit 140. For this purpose, the second electrode supply unit 130 may include a winding roll on which the second electrode 15, cut into sheet shapes, is wound. Furthermore, the second electrode supply unit 130 may include other components such as shafts and rollers necessary for mounting and unwinding the winding roll.

[0180] The diaphragm supply unit 110 may be configured to individually unwind and supply the first diaphragm 11 and the second diaphragm 12, which are overlapped and wound into a single roll. For this purpose, the diaphragm supply unit 110 may include a diaphragm winding roll 10 as described above according to this disclosure. The diaphragm supply unit 110 may include other components such as shafts and rollers necessary for mounting the diaphragm winding roll 10 and unwinding the diaphragm from the diaphragm winding roll 10. As described above, the diaphragm winding roll 10 includes the first diaphragm 11 and the second diaphragm 12, and the winding unit 140 may sequentially stack and wind the first electrode 14, the first diaphragm 11, the second electrode 15, and the second diaphragm 12. Alternatively, the winding unit 140 may sequentially stack and wind the second diaphragm 12, the first electrode 14, the first diaphragm 11, and the second electrode 15.

[0181] like Figure 3 As shown, in the electrode assembly manufacturing apparatus 100, the first diaphragm 11 may be located between the first electrode 14 and the second electrode 15, and the second diaphragm 12 may be located on the outside of the second electrode 15.

[0182] As another example, Figure 4 As shown, in the electrode assembly manufacturing apparatus 100, the first diaphragm 11 may be located between the first electrode 14 and the second electrode 15, and the second diaphragm 12 may be located on the outside of the first electrode 14. In other words, in Figure 3 In the electrode assembly manufacturing apparatus 100, the second diaphragm 12 is located on the outside of the second electrode 15, while Figure 4 In the electrode assembly manufacturing apparatus 100, the second diaphragm 12 is located on the outside of the first electrode 14.

[0183] In one embodiment of this disclosure, such as Figure 3 As shown in Figure 4, the electrode assembly manufacturing apparatus 100 may further include at least one first guide roller 111, which supplies the first diaphragm 11, supplied by unwinding the diaphragm winding roll 10, between the first electrode 14 and the second electrode 15; and at least one second guide roller 112, which supplies the second diaphragm 12, supplied by unwinding the diaphragm winding roll 10, in a direction opposite to one surface of one of the first electrode 14 and the second electrode 15.

[0184] In one embodiment of this disclosure, the path along which the first diaphragm 11 travels from the diaphragm supply unit 110 to the winding unit 140 is referred to as the first diaphragm supply path. The first diaphragm supply path can refer to the path along which the first diaphragm 11 is unwound from the diaphragm supply unit 110 and moves to the winding unit 140 via the outer periphery of the first guide roller 111. The first guide roller 111 can be positioned such that the first diaphragm 11 located in the first diaphragm supply path has tension.

[0185] In one embodiment of this disclosure, the path along which the second diaphragm 12 travels from the diaphragm supply unit 110 to the winding unit 140 is referred to as the second diaphragm supply path. The second diaphragm supply path can refer to the path along which the second diaphragm 12 is unwound from the diaphragm supply unit 110 and moves to the winding unit 140 via the outer periphery of the second guide roller 112. The second guide roller 112 can be positioned such that the second diaphragm 12 located in the second diaphragm supply path has tension.

[0186] In one embodiment of this disclosure, the at least one second guide roller 112 may be arranged such that the second diaphragm supply path extending from the diaphragm supply unit 110 to the winding unit 140 bypasses the first electrode supply unit 120 or the second electrode supply unit 130.

[0187] For example, such as Figure 3 As shown, the at least one second guide roller 112 may be arranged such that the second diaphragm supply path extending from the diaphragm supply unit 110 to the winding unit 140 bypasses the second electrode supply unit 130.

[0188] In addition, such as Figure 4 As shown, the at least one second guide roller 112 may be arranged such that the second diaphragm supply path extending from the diaphragm supply unit 110 to the winding unit 140 bypasses the first electrode supply unit 120.

[0189] In addition, refer to Figure 3 and 4 The electrode assembly manufacturing apparatus 100 may further include a first electrode guide roller 121, which supplies the first electrode 14 from the first electrode supply unit 120 to the winding unit 140, and may further include a second electrode guide roller 131, which supplies the second electrode 15 from the second electrode supply unit 130 to the winding unit 140. The first electrode guide roller 121 and the second electrode guide roller 131 can apply tension to the wound first electrode 14 and second electrode 15, thereby reducing defects in the jelly roll electrode assembly.

[0190] As previously referenced Figure 1 The winding length of the first diaphragm 11 and the winding length of the second diaphragm 12 can be the same, or the winding length of the second diaphragm 12 can be longer than the winding length of the first diaphragm 11.

[0191] In one embodiment of this disclosure, when the winding length of the second diaphragm 12 is longer than the winding length of the first diaphragm 11, the difference between the winding length of the second diaphragm 12 and the winding length of the first diaphragm 11 can be equal to or longer than the difference between the length of the second diaphragm supply path and the length of the first diaphragm supply path. In this case, the first diaphragm 11 and the second diaphragm 12 can be included in the same amount in the jelly-shaped electrode assembly wound by the winding unit 140, and the manufacturing of the electrode assembly will not be interrupted due to a shortage of the second diaphragm 12.

[0192] On the other hand, in one embodiment of this disclosure, when the diaphragm supply unit 110 is unwound while the electrode assembly manufacturing apparatus 100 is operating, the lengths of the first diaphragm supply path and the second diaphragm supply path may be different, but the lengths of the first diaphragm supply path and the second diaphragm supply path can be defined as follows. For example, the length from the point where the first diaphragm 11 contacts (is perpendicular to) the diaphragm winding roll 10 to the portion where the first diaphragm 11 contacts (is perpendicular to) the electrode assembly manufactured in the winding unit 140 can be the length of the first diaphragm supply path. In this case, the first guide roller 111 must be positioned to contact the first diaphragm 11, each of the diaphragm winding rolls 10, and the electrode assembly. The length of the second diaphragm supply path can also be defined in the same manner.

[0193] In one embodiment of this disclosure, the electrode assembly manufacturing apparatus 100 may further include at least one tension roller 150 to apply tension as the first electrode 14, the second electrode 15, and the diaphragms 11 and 12 are supplied from the respective supply units 110, 120, and 130 to the winding unit 140. When the tension roller 150 is also included, the first electrode 14, the first diaphragm 11, the second electrode 15, and the second diaphragm 12 can be stacked without folding, thereby improving the manufacturing yield of the electrode assembly and reducing the defect rate.

[0194] On the other hand, in one embodiment of this disclosure, the positions of the diaphragm supply unit 110, the first electrode supply unit 120, and the second electrode supply unit 130 in the electrode assembly manufacturing apparatus 100 can be freely modified according to the purpose. For example, as Figure 5As shown, the positions of the first electrode supply unit 120 and the second electrode supply unit 130 can be symmetrical relative to the winding unit 140.

[0195] <Electrode Assembly Manufacturing Method>

[0196] This disclosure provides a method for manufacturing an electrode assembly. The electrode assembly manufactured in this disclosure is a jelly roll type electrode assembly.

[0197] The electrode assembly manufacturing method disclosed herein includes: simultaneously supplying a first electrode, a first diaphragm, a second electrode, and a second diaphragm in a roll-to-roll manner, sequentially stacking and winding the first electrode, the first diaphragm, the second electrode, and the second diaphragm in one direction, wherein the first diaphragm and the second diaphragm are wound in an overlapping manner in a roll, and then unwinding and supplying them as a single sheet. For example, the electrode assembly is manufactured using the overlapping and wound diaphragm.

[0198] The electrode assembly manufacturing method can be used as described above. Figures 3 to 5 The electrode assembly manufacturing apparatus 100 shown and described herein is used for this process.

[0199] Reference Figure 6 An electrode assembly manufacturing method according to one embodiment of the present disclosure includes: (S10) Separate two or more diaphragms individually from a diaphragm winding in which two or more diaphragms are stacked and wound; (S20) Supply the diaphragm that is separated individually in the separation; (S30) Supply to the first electrode; (S40) Supply the second electrode; and (S50) The diaphragms that were separated in the separation are stacked and wound between the first electrode and the second electrode and on the outside of the first electrode or the second electrode.

[0200] This method can also be used as described above. Figures 3 to 5 The electrode assembly manufacturing apparatus 100 shown and described herein is used. The electrode assembly manufacturing method of this disclosure utilizes a diaphragm winding roll 10 in which two or more diaphragms are stacked and wound, which simplifies the process. When the diaphragms are exhausted, continuous processing can be achieved by replacing the diaphragm winding roll 10 once.

[0201] Step S10, which involves separating the two or more layers of diaphragms individually from the diaphragm winding roll 10, can be a step in which a worker manually separates the two or more layers of diaphragms individually. Furthermore, step S20, which involves supplying the individually separated diaphragms, can be a step in which a worker manually attaches the separated diaphragms to the winding unit 140.

[0202] In one embodiment of this disclosure, steps S20 to S50 can be performed simultaneously after step S10. For example, in the electrode assembly manufacturing method of this disclosure, after step S10, which separates the two or more layers of separators individually from the separator winding roll 10, the following steps can be performed simultaneously: step S20, which supplies the individually separated separators; step S30, which supplies the first electrode; step S40, which supplies the second electrode; and step S50, which stacks and winds the individually separated separators between the supplied first electrode 14 and second electrode 15 and on the outside of the first electrode 14 or the second electrode 15.

[0203] In one embodiment of this disclosure, the two or more diaphragms include a first diaphragm 11 and a second diaphragm 12, and step S50 may include stacking and winding the first electrode 14, the first diaphragm 11, the second electrode 15 and the second diaphragm 12 in sequence, or stacking and winding the second diaphragm 12, the first electrode 14, the first diaphragm 11 and the second electrode 15 in sequence.

[0204] As described above, the winding length of the first diaphragm 11 and the winding length of the second diaphragm 12 can be the same, or the winding length of the second diaphragm 12 can be longer than the winding length of the first diaphragm 11. In this case, the first diaphragm 11 and the second diaphragm 12 can be included in the same amount in the jelly-shaped electrode assembly wound by the winding unit 140, and the manufacturing of the electrode assembly will not be interrupted due to a shortage of the second diaphragm 12.

[0205] According to one embodiment, step S10 is performed using the diaphragm supply unit 110, and step S50 is performed using the winding unit 140. By using the diaphragm roll 10, where the winding length of the second diaphragm 12 is longer than the winding length of the first diaphragm 11, the difference between the winding length of the second diaphragm 12 and the winding length of the first diaphragm 11 can be equal to or longer than the difference between the length of the second diaphragm supply path and the length of the first diaphragm supply path. In this case, the first diaphragm 11 and the second diaphragm 12 can be included in the same quantity in the jelly-shaped electrode assembly wound by the winding unit 140, and the manufacturing of the electrode assembly will not be interrupted due to a shortage of the second diaphragm 12.

[0206] The present disclosure is described in more detail below by way of examples. However, the following examples are intended to illustrate the present disclosure, and the scope of the present disclosure is not limited thereto.

[0207] Example

[0208] Liquid paraffin oil (Kukdong Yuhwa, LP 350P, 68 cSt) as the first diluent and polyethylene resin (Daehan Yuhwa, VH 035) with a weight average molecular weight of 600,000 as the first polymer resin were mixed in a 3:7 ratio and introduced into an extruder equipped with a T-die. Conveying, mixing, and extrusion were controlled at a temperature of 210°C, and the extrusion speed was controlled at 0.37 m / min. The composition passing through the extruder was then passed through a cooling casting roll maintained at 45°C to produce a first unstretched sheet.

[0209] Simultaneously, liquid paraffin oil (Kukdong Yuhwa, LP 350P, 68 cSt) as a second diluent and polyethylene resin (Daehan Yuhwa, VH 035) with a weight average molecular weight of 600,000 as a second polymer resin were mixed in a 3:7 ratio and introduced into an extruder equipped with a T-die. Conveying, mixing, and extrusion were controlled at a temperature of 210°C, and the extrusion speed was controlled at 0.37 m / min. The composition passing through the extruder was then passed through a cooling casting roll maintained at 45°C to produce a second unstretched sheet.

[0210] The first unstretched sheet and the second unstretched sheet are stacked to prepare an unstretched stacked sheet.

[0211] The unstretched stacked sheets were biaxially stretched using a tenter frame-type sequential stretching machine, wherein MD stretching (longitudinal stretching) and then TD stretching (transverse stretching) were performed, and the diluent was extracted to prepare the stacked separator. In both cases, the MD stretching ratio was 5 times and the TD stretching ratio was 6 times. The stretching temperature was 113°C for MD and 121°C for TD. The diluent was extracted using a dichloromethane / water mixture at an extraction rate of 2 m / min.

[0212] The stacked diaphragms were heat-fixed at 129°C under conditions of stretching to 140% of their initial width and then gradually reducing to 120%. The heat-fixing speed was 4 m / min, and the thickness of the first and second diaphragms constituting the stacked diaphragms was 10.0 μm, with a winding length of 2,000 m.

[0213] The obtained stacked diaphragms are wound in one direction to create a diaphragm winding roll.

[0214] Experimental Example

[0215] In the diaphragm windings manufactured in the above embodiments, the first diaphragm and the second diaphragm are separated, and the air permeability and resistance characteristics are measured, as shown in Table 1 below.

[0216] [Table 1]

[0217] The first and second diaphragms manufactured according to the embodiments have substantially the same air permeability and electrical resistance characteristics.

[0218] Measurement of air permeability

[0219] The diaphragm in this example was measured using a Gurley permeability meter according to JIS P-8117. The measurement was taken for 100 ml of air passing through a membrane with a diameter of 28.6 mm and an area of ​​645 mm². 2 The time.

[0220] Measurement of resistance characteristics

[0221] The diaphragm manufactured in the examples was immersed in an electrolyte (ethylene carbonate (EC): diethyl carbonate (DEC) = 3:7, LiPF6 1.0 M), and then the AC resistance was measured. The results are shown in Table 1 above. The AC resistance is a value measured using EIS (Ametek) at 1 kHz.

[0222] Although the present disclosure has been described above with reference to limited embodiments and accompanying drawings, the present disclosure is not limited thereto, and those skilled in the art can make various modifications and variations within the technical spirit of the present disclosure and the equivalents of the appended claims.

Claims

1. A wound diaphragm comprising two or more layers of diaphragms stacked and wound.

2. The wound diaphragm according to claim 1, wherein the two or more diaphragms comprise a first diaphragm and a second diaphragm, and The winding length of the second diaphragm is longer than that of the first diaphragm.

3. The wound diaphragm according to claim 1, wherein the two or more diaphragms comprise a first diaphragm and a second diaphragm, and One end of the first diaphragm and the second diaphragm is wound in such a way that it wraps around the remaining end, such that the one end is unwound before the remaining end during unwinding.

4. The wound diaphragm according to claim 1, wherein the two or more diaphragms comprise a first diaphragm and a second diaphragm. The first diaphragm comprises a first porous polymer substrate and a first inorganic heat-resistant layer on at least one surface of the first porous polymer substrate, the first inorganic heat-resistant layer comprising first inorganic particles and a first binder polymer, and The second diaphragm comprises a second porous polymer substrate and a second inorganic heat-resistant layer on at least one surface of the second porous polymer substrate, the second inorganic heat-resistant layer comprising second inorganic particles and a second adhesive polymer.

5. The wound diaphragm according to claim 4 further comprises an intermediate layer film on at least one of the first inorganic heat-resistant layer and the second inorganic heat-resistant layer.

6. A method for manufacturing a wound diaphragm, the method comprising: A first mixture comprising a first diluent and a first polymer resin is introduced into an extruder, then extruded and cooled to obtain a first unstretched sheet; A second mixture comprising a second diluent and a second polymer resin is introduced into an extruder, then extruded and cooled to obtain a second unstretched sheet; The first unstretched sheet and the second unstretched sheet are stacked to obtain an unstretched stacked sheet; The unstretched stacked sheets are first stretched in a first direction to obtain a first stretched stacked sheet; The first stretched stacked sheet is stretched a second time in a second direction to obtain a second stretched stacked sheet; Extract the first diluent and the second diluent from the second stretched stacked sheet to obtain a stacked diaphragm in which the first diaphragm and the second diaphragm are stacked; as well as The stacked diaphragm obtained in the extraction is wound up.

7. The method according to claim 6, further comprising: The stacked diaphragms are thermally fixed.

8. The method of claim 6, wherein the first mixture further comprises a first initiator and a first crosslinking agent. The second mixture further comprises a second initiator and a second crosslinking agent, and The method further includes crosslinking the stacked membrane obtained by extracting the first diluent and the second diluent.

9. A method for manufacturing a wound diaphragm, the method comprising: A third mixture containing a third diluent and a third polymer resin is introduced into an extruder, then extruded and cooled to obtain a third unstretched sheet; A fourth mixture containing a fourth diluent and a fourth polymer resin is introduced into an extruder, then extruded and cooled to obtain a fourth unstretched sheet; The third unstretched sheet and the fourth unstretched sheet are respectively stretched in a first direction to obtain the third sheet and the fourth sheet after the first stretch. The first stretched third piece and the first stretched fourth piece are respectively stretched in the second direction to obtain the second stretched third piece and the second stretched fourth piece. The third diluent and the fourth diluent are extracted from the second stretched third sheet and the second stretched fourth sheet, respectively, to obtain the third porous polymer substrate and the fourth porous polymer substrate; A slurry for forming a third inorganic heat-resistant layer, comprising third inorganic particles and a third binder polymer, is applied to at least one surface of the third porous polymer substrate and dried to form a third inorganic heat-resistant layer. A slurry comprising fourth inorganic particles and a fourth binder polymer, for forming a fourth inorganic heat-resistant layer, is applied to at least one surface of the fourth porous polymer substrate and dried to form a fourth inorganic heat-resistant layer; and The third porous polymer substrate on which the third inorganic heat-resistant layer is formed and the fourth porous polymer substrate on which the fourth inorganic heat-resistant layer is formed are stacked and wound together.

10. The method of claim 9, further comprising: The third porous polymer substrate and the fourth porous polymer substrate obtained by extracting the third and fourth diluents are respectively heat-fixed.

11. The method of claim 9, wherein the third mixture further comprises a third initiator and a third crosslinking agent. The fourth mixture further comprises a fourth initiator and a fourth crosslinking agent, and The method further includes crosslinking the third porous polymer substrate and the fourth porous polymer substrate obtained by extracting the third diluent and the fourth diluent, respectively.

12. The method of claim 9, wherein the stacking and winding comprises further stacking an intermediate layer film on at least one of the third inorganic heat-resistant layer and the fourth inorganic heat-resistant layer, and then winding.

13. An electrode assembly manufacturing apparatus, comprising: A wound diaphragm, wherein two or more diaphragms are stacked and wound together; A diaphragm supply unit is configured to individually separate and supply two or more layers of diaphragms from the wound diaphragm. The first electrode supply unit is configured to supply the first electrode; The second electrode supply unit is configured to supply a second electrode; and The winding unit is configured to individually stack and wind the diaphragms that are separated and supplied by the diaphragm supply unit between the first electrode and the second electrode and on the outside of the first electrode or the second electrode.

14. The electrode assembly manufacturing apparatus of claim 13, wherein the two or more diaphragms stacked in the wound diaphragm comprise a first diaphragm and a second diaphragm, and The winding length of the second diaphragm is longer than that of the first diaphragm.

15. The electrode assembly manufacturing apparatus of claim 13, wherein the two or more diaphragms stacked in the wound diaphragm comprise a first diaphragm and a second diaphragm, and One end of the first diaphragm and the second diaphragm is wound in such a way that it wraps around the remaining end, such that the one end is unwound before the remaining end during unwinding.

16. The electrode assembly manufacturing apparatus of claim 13, wherein the two or more diaphragms stacked in the wound diaphragms comprise a first diaphragm and a second diaphragm, and The winding unit stacks and winds the first electrode, the first diaphragm, the second electrode, and the second diaphragm in sequence.

17. The electrode assembly manufacturing apparatus according to claim 16, further comprising: At least one first guide roller is configured to supply the first diaphragm, supplied by unwinding the wound diaphragm, to the gap between the first electrode and the second electrode; and At least one second guide roller is configured to supply the second diaphragm, supplied by unwinding the wound diaphragm, in a direction opposite to one of the surfaces of the first electrode and the second electrode.

18. The electrode assembly manufacturing apparatus of claim 17, wherein the at least one second guide roller is arranged such that a second diaphragm supply path extending from the diaphragm supply unit to the winding unit bypasses the first electrode supply unit or the second electrode supply unit.

19. The electrode assembly manufacturing apparatus of claim 16, wherein the winding length of the second diaphragm is longer than the winding length of the first diaphragm.

20. The electrode assembly manufacturing apparatus of claim 16, wherein the winding length of the second diaphragm is longer than the winding length of the first diaphragm, and The difference between the winding length of the second diaphragm and the winding length of the first diaphragm is equal to or longer than the difference between the length of the second diaphragm supply path extending from the diaphragm supply unit to the winding unit and the length of the first diaphragm supply path extending from the diaphragm supply unit to the winding unit.

21. A method for manufacturing an electrode assembly, the method comprising: Separate two or more diaphragms individually from a wound diaphragm in which two or more diaphragms are stacked and wound together; The diaphragm, which is individually separated in the separation process, is supplied. Supply to the first electrode; Supply to the second electrode; as well as The diaphragms, which were separated individually during the separation, are stacked and wound between the first electrode and the second electrode, and on the outside of the first electrode or the second electrode.

22. The method of claim 21, wherein supplying the diaphragm, supplying the first electrode, supplying the second electrode, and stacking and winding the diaphragm are performed simultaneously after separating the two or more layers of diaphragm.

23. The method of claim 21, wherein the two or more diaphragms comprise a first diaphragm and a second diaphragm, and In the process of stacking and winding the diaphragm, the first electrode, the first diaphragm, the second electrode, and the second diaphragm are stacked and wound in sequence.

24. The method of claim 23, wherein the winding length of the second diaphragm is longer than the winding length of the first diaphragm.

25. The method of claim 23, wherein separating the two or more diaphragms is performed using a diaphragm supply unit, and stacking and winding the diaphragms is performed using a winding unit. The winding length of the second diaphragm is longer than that of the first diaphragm, and The difference between the winding length of the second diaphragm and the winding length of the first diaphragm is equal to or longer than the difference between the length of the second diaphragm supply path extending from the diaphragm supply unit to the winding unit and the length of the first diaphragm supply path extending from the diaphragm supply unit to the winding unit.

26. A method for manufacturing an electrode assembly, the method comprising: While supplying the first electrode, the first diaphragm, the second electrode, and the second diaphragm in a roll-to-roll manner, the first electrode, the first diaphragm, the second electrode, and the second diaphragm are sequentially stacked and wound in one direction. The first diaphragm and the second diaphragm are wound in an overlapping manner in a roll, and then unwound and supplied as a single sheet.

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